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Revisiting Brucellosis in the Greater Yellowstone Area (2017)

Chapter: 2 Geographic Scope of Populations and Disease and Change in Land Use

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Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
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Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
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Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 21
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 22
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 23
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 24
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 25
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 26
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 27
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 28
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 29
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 30
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 31
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 32
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 33
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 34
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 35
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 36
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 37
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 38
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 39
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 40
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 41
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 42
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 43
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 44
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 45
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 46
Suggested Citation:"2 Geographic Scope of Populations and Disease and Change in Land Use." National Academies of Sciences, Engineering, and Medicine. 2017. Revisiting Brucellosis in the Greater Yellowstone Area. Washington, DC: The National Academies Press. doi: 10.17226/24750.
×
Page 47

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2 Geographic Scope of Populations and Disease and Change in Land Use 1. INTRODUCTION There have been significant changes in the population sizes and distributions of bison and elk in the Greater Yellowstone Area (GYA) since the 1998 National Research Council report. Both bison and elk numbers have increased overall. Bison ranges have expanded and there is increased intermixing among herds. Elk numbers have increased in many areas, while the population size of the well-known Yellow- stone northern range herd has declined. Elk are now recognized as a large reservoir of B. abortus. In addi- tion, wolves were reintroduced to the GYA and grizzly bear numbers have increased. As a result of all these changes, brucellosis transmission dynamics are considerably different than in 1998. The changes in B. abortus reservoir and transmission dynamics in the GYA are also outcomes of processes associated with the ecologies, population dynamics, and spatial distributions of bison and elk. Bison and elk also play critical roles in the functioning of the Greater Yellowstone Ecosystem as a whole. They affect and also respond to vegetation, soils, other wildlife populations, and human activities. This chapter examines the ecological context of brucellosis in the GYA as affected by the abun- dances and spatial distributions of its host species: elk and bison. It draws on best available data to pro- vide a quantitative basis for understanding the abundances and spatial distributions of the two main host species, and it explores factors (such as climate, predators, land use, hunting, changes in management ac- tivities) that cause host abundances and distributions to change. 2. ELK POPULATIONS AND DISTRIBUTIONS One of the most significant changes since 1998 is an increased recognition of the central role that elk play in B. abortus transmission. An increase in elk numbers across the GYA is one factor contributing to a change in the role of elk, with more than 125,000 counted elk distributed among 11 major herds. The ranges and migration pathways of nine of these major herds are shown in Figure 2-1. Dynamics of the northern Yellowstone elk population have been intensively studied for decades (Houston, 1982; Coughenour and Singer, 1996; Singer et al., 1997; Taper and Gogan, 2002; Barmore, 2003; White and Garrott, 2005a,b; Varley and Boyce, 2006; Eberhart et al., 2007). In 1969, a policy of natural regulation ended artificial reductions that enabled the elk population to swell to its highest levels in the 1980s with more than 18,000 counted elk (Coughenour and Singer, 1996) (see Figure 2-2). In the late 1990s, the population steadily declined following wolf reintroduction, with the 2016 population count at less than 5,000 elk. In modeling and predicting elk population equilibrium levels in the GYA pre- wolves, there was general agreement that food limitation would result in an equilibrium number of ap- proximately 15,000-18,000 counted elk on the northern range, which corresponds to approximately 20,000-24,000 actual elk in the absence of wolves (Coughenour and Singer, 1996; Taper and Gogan, 2002; Coughenour, 2005; Varley and Boyce, 2006). Prepublication Copy—Subject to Further Editorial Revision 19

Revisiting Brucellosis in the Greater Yellowstone Area g i r e FIGURE 2-1 Map of mi 2 igration corrido winter ran ors, nges (blue poly ygons) and sum mmer ranges (t polygons) o 9 of tan of 11 major elk herds in the GYA. This map excludes approximately one-third of th southern GY that includ elk e e m a he YA des in the Afto on-Pine, the Pin nedale-South Wind River are and eastern Idaho, west of Grand Teto National Par (see W eas, rn on rk Figure 2-4 and Tables 2-3 2-4). SOUR 3, RCE: National Geographic, 20 G 016. 2.1 Wolv and Hun ves nting The beginning of the decline in northern range elk nu umbers coinci ided with the reintroducti of e ion wolves in 1995 and 1996, suggestin that wolves were, at leas in part resp n ng s st ponsible. How wever, other fa factors are also probably playi a role, inc p ing cluding a high hunting rem moval of elk mmigrating nor of Yellow rth wstone National Park (YNP), and the fact that hunting harvests have been mostly of prime-aged female elk with P t h e y k high reprooductive valu (Eberhart et al., 2007). Wolf predati now exce ue e ion eeds hunter harvest, but it has a smaller efffect on elk population dy p ynamics becau wolves co use oncentrate on calves and o n older females with s less repro oductive value (White et al., 2003; Sm et al., 200 White an Garrott, 20 e a mith 04; nd 005a; Evans et al., 2006; Wright et al., 20006; Eberhart et al., 2007). Early empiri models of the effects o climate, ha ical of arvest, and wolve on this elk population in es ndicated that population re p esponses to w predation were compen wolf nsato- ry, meaning that preda ators mainly removed anim that wou die of oth causes an r mals uld her nyway (Vucet tich et al., 2005). Additionally there were several cons y, secutive years of drought d s during 2000-2006, which could have reduuced forage an consequen affected elk (MacNult 2015). Elk starvation w documen nd ntly e ty, k was nted in 20 Pre epublication Copy—Subje to Further Editorial Rev ect r vision

Geogr raphic Scope of Population and Diseas and Chang in Land Us ns se ge se late winte 2003-2004 which was mild but preceded by several year of low an er 4, p rs nnual precipiitation (Vucetich et al., 2005) Also, grizzl bears—wh h ). ly hich are majo predators o elk, particu or on ularly elk cal lves— doubled to tripled in number between the mid-1980s and m t n mid-2000s (Si 1997; Harris et al., inger et al., 1 2007; Harroldson, 2008 Barber-Mey et al., 200 Schwartz e al., 2009; U 8, yer 08; et USFWS, 2016 6). 2.2 Cause of Change in Elk Spa es es atial Distribu utions Wol lves also shift elk distributions, as wolv reduce the availability of habitat and total forage. As a t ves e d result, a greater numbe of elk are now found at lower eleva g er n t ations outside of YNP whe wolves ar less ere re abundant (White et al. 2012). Elk are less likel to occupy areas with d ., ly deeper snow o other cond or ditions that increase predation risk in the presence of wolves (Mao e al., 2005; W n p w et White et al., 2009, 2013). Thus wolves may have also contributed to the decline in the northe Yellowsto elk herd indirectly, th m t e ern one hrough a contract tion of the elk range and associated for k a rage. The num mbers (see Fig gure 2-3a) an proportion (see nd ns Figure 2-3 of elk her using habitats north of YNP increas markedly during the m and late 1970s 3b) rds f sed y mid- in response to increased population size, chang in the tim n ges ming of elk h hunts, and prrotection of wwinter ranges ou utside of YNP (Coughenou and Singer, 1996). The p P ur , proportion of Yellowstone elk north of YNP f e f in winter increased steadily through 2011 and ha remained h h as high during 22011-2015 (se Figure 2-3) The ee ). increased percentage is due to the decrease in tot population size rather th an increa in number out- s tal n han ase rs side YNP. FIGURE 2-2 Northern Yellowstone elk numbers. SOURCES: Co e S oughenour and Singer, 1996 Taper and G d 6; Gogan, 2002; White and Garrott, 2005a; Cross, 2013. , , Prepublic cation Copy— —Subject to Fu urther Editori Revision ial 21

Revisiting Brucellosis in the Greater Yellowstone Area g i r e FIGURE 2-3 Elk num mbers and per rcentages north of Yellows h stone National Park and o Dome Mou l on untain. SOURCES Coughenour and Singer, 19 S: r 996; Taper and Gogan, 2002; White and Ga d ; arrott, 2005a; C Cross, 2013. Elk grouping beh havior has also changed, as Northern Yellowstone elk have been found in larger groups following wolf reintroductio (Mao et al 2005). Alth f on l., hough there w an increa in large g was ase groups found outtside YNP, thhere was a deccrease in larg groups foun inside YN where the elk populatio has ge und NP on declined (White et al., 2012). ( 22 Pre epublication Copy—Subje to Further Editorial Rev ect r vision

Geographic Scope of Populations and Disease and Change in Land Use The decline in elk numbers on the northern winter range and the increased proportions of the herd wintering outside YNP could also be due in part to increased competition for forage from increasing numbers of bison. Unlike elk, which migrate to higher elevations in summer, bison remain on the low elevation elk winter range during summer, thereby depleting forage for wintering elk. Ecosystem model- ing experiments indicate greater numbers of bison could reduce elk numbers due to dietary and habitat overlaps, but not to the extent to which elk numbers have actually declined (Coughenour, 1994). 2.3 Madison Headwaters Herd The small herd of elk that resides in the Madison River headwaters within YNP is non-migratory. This herd spends both winters and summers within YNP, and is not subjected to human hunting (Garrott et al., 2003, 2009). The population has declined markedly from approximately 600 in 2001 to about 100 in 2009, likely due to wolves and grizzly bears (Hamlin and Cunningham, 2009). Multiple wolf packs became established by 2002 with a total of 30-40 animals. High wolf densities and moderate elk densities resulted in 20% of elk being taken by wolves (Garrott et al., 2005). Grizzly bear numbers increased from about 10 in the mid-1980s to more than 20 by 2004 (Haroldson, 2006, 2007; Hamlin and Cunningham, 2009). The ratio of grizzly bears to elk was higher in the Madison-Firehole and Gallatin Canyon areas than any other areas across the GYA (Hamlin and Cunningham, 2009). 2.4 Elk Herds Wintering North and West of Yellowstone National Park Approximately 30,000 elk in elk management units (EMUs) are located north and west of YNP within the brucellosis designated surveillance area (DSA) (see Table 2-1 and Figure 2-4). Approximately 56% of 22 core winter ranges are privately owned, and 10 of the winter ranges in this area have over 80% private ownership (personal communication, Quentin Kujala, Montana Department of Fish, Wildlife, and Parks, October 30, 2015). Elk numbers in EMUs north and west of YNP in Montana have been increasing since the late 1970s (Cross et al., 2010a), as they have been in many parts of Montana (MDFWP, 2004). In 2008, there were 5-9 times more elk in EMUs in the western Paradise and eastern Madison valleys of Montana than in 1975. Elk numbers have also been increasing in EMUs just to the north and northwest of the DSA (see Figure 2-5). These include the Bridger, Crazy Mountain, Pioneer, Tendy, and Tobacco Root EMUs. Elk group sizes have also been increasing, and group size distributions have been increasing in the eastern Madison and western Paradise valleys (Cross et al., 2010b). From 2003-2009, there were more large groups and larger group sizes in the northern YNP herd wintering outside YNP than from 1987- 1992 (White et al., 2012). In the Madison drainage, elk aggregated in somewhat larger groups in response to wolf predation risk (White et al., 2009). Recently, a pattern was observed of increasing group sizes with increasing density across 27 herd units in this region, and there was no evidence that wolf predation risk affected elk aggregation patterns (Proffitt et al., 2015). Changes in land ownership have also affected elk migration and aggregation patterns in this region, which have in turn affected hunter access. In the Madison-Gallatin EMU, the Montana Department of Fish, Wildlife, and Parks (MDFWP) reported that “There is limited access to public land and adjacent private land in some portions of the EMU due to changes in land ownership. This has resulted from a change in land ownership toward landowners who do not make their primary living from ranching” (MDFWP, 2004). Elk migrating from YNP to winter in portions of this EMU, in combination with non- YNP elk, results in high numbers of elk which makes it difficult to control numbers through late season hunting (MDFWP, 2004). Likewise in the Absaroka EMU, MDFWP further reports “There has been an increasing number of landowners who do not make their primary living from ranching, and these land- owners have less interest than traditional landowners in allowing elk hunting [on their property]” (MDFWP, 2004). This has created elk refugia, reduced elk harvest, and resultant increased elk numbers. Counts in this EMU are far above management objectives (see Table 2-1). Prepublication Copy—Subject to Further Editorial Revision 23

Revisiting Brucellosis in the Greater Yellowstone Area TABLE 2-1 Elk Numbers in Elk Management Units (Hunting Districts) North and Northwest of YNP, But Within the Brucellosis DSA, in 2015 Hunting District Count 2015 Objective Northern Yellowstone 313 3,714 4,000 Absaroka 317 934 900 520 1,922 1,050 560 2,018 700 Total 4,874 2,650 Gallatin/Madison 301, 309 587 500 310 428 1,500 311 2,069 2,500 314 3,381 3,000 360 South 773 1,000 360 North 865 1,200 361 – 150 362 2,500 2,952 Total 10,603 12,802 Gravelly 322-327, 330 10,543 8,000 All Elk Management Units Total 29,734 27,452 SOURCE: MDFWP, 2016. Elk avoidance of hunted areas has resulted in elk groups being unavailable for harvest in the Madi- son Valley, which is winter range for approximately 5,000 elk (Proffitt et al., 2010a). During the hunting season, elk shifted to areas that were closed to hunting, including privately-owned lands and a state Wild- life Management Area (Wall Creek). The probability of finding elk on such designated refuge areas has more than doubled, with Global Positioning System (GPS)-collared elk in the Madison Valley showing preference for areas that were privately owned, facing south, with steeper slopes, lower road densities, and more green forage (Proffitt et al., 2010b). Elk selection for private lands with green forage increases the probability of overlap with cattle and increases the risk of disease transmission. 2.5 Elk Herds Wintering East and South of Yellowstone National Park Boundaries The Clarks Fork Herd East of YNP The Clarks Fork elk herd consists of about 4,500 migratory and non-migratory elk that inhabit the Absaroka Mountains northeast of YNP (Middleton et al., 2013a,b). The winter range of the migratory herd segment includes areas east of YNP, extending to the foothills northwest of Cody. In the spring, the migrants move 40-60 km to high elevation summer ranges inside YNP (Middleton et al., 2013a). The res- ident herd segment spends winters and summers northwest of Cody, overlapping a portion of the migrato- ry winter range. The wintering ranges of both herd segments and the summer range of the resident seg- ment are included in the Clarks Fork Hunt Unit. 24 Prepublication Copy—Subject to Further Editorial Revision

Geogr raphic Scope of Population and Diseas and Chang in Land Us ns se ge se FIGURE 2-4 Elk manag 2 gement units in Montana, elk hunt units in Wyoming, and game management units in Idaho n k d n in relation to the design n nated surveillan area and the YNP boun nce 2014 (red lines Elevations above ndary, as of 2 s). 2,500 m ar shown in gra SOURCE: MDFWP and WGFD data pr re ay. M W rovided to com mmittee. The productivity of the migra herd has declined mark ant d kedly, with calf recruitment decreasing 70% g over 21 years and preggnancy decrea asing 19% in 4 years. The decline may be partly du to increased dry- e y ue d ness in th region, par he rticularly on summer range with short durations of green-up o s es, ter occurring (peerhaps 16 days) since 2002. Also, the mig A grant Clarks Fork elk are e F exposed to fo times as m our many grizzly bears and wolve as resident elk (Middlet et al., 201 es t ton 13a). Along w the Cody herd and the Jackson her the with y e rd, Clarks Fo elk have experienced reduced calf recruitment (4 ork e r r 4-16%) and ppopulation gr rowth rate (2--11%) from 1987 to 2010 (M 7 Middleton et al., 2013c). During this tim some grizzly bears sh a D me, hifted their di to iets less preda ation on trout, and likely more predatio on elk calv This diet shift may ha been a res of m on ves. ave sult the declin in cutthroat trout in and around Yello ne t owstone Lake which in tur is due to th invasion o lake e, rn, he of Prepublic cation Copy— —Subject to Fu urther Editori Revision ial 25

Revisiting Brucellosis in the Greater Yellowstone Area g i r e trout (Midddleton et al., 2013c). The is debate on whether t grizzly be population has increased in- ere the ear n side YNP (Schwartz et al., 2006; Hamlin and Cu t H unningham, 22009), however, the populaation has incr reased in areas outside of YN (Schwartz et al., 2006). The combin o NP nation of mor bears and shifts in bear diets re r could hav acted syner ve ecruitment of migratory el in this herd (Middleton et al., rgistically to reduce calf re r f lk d 2013c). The largest elk gr roups in this area tend to be in open ran land syste a b nge ems. Wolf nummbers are possitive- ated with larg groups in open areas (Brennan et a 2015), wh in foreste areas elk group ly correla ger ( al., hile ed sizes tend to be smalle in the prese d er ence of wolve (Creel and Winnie, 2005). As a resul of wolf pre es lt esence in large op areas in this region, th are a few very large el groups (see Figure 2-6). pen t here lk e . Elk Herds East of YNP s P Herd east of YN (see Figu 2-4) totale 17,425 elk in 2015, with an object ds NP ure ed k tive of 17,065 (see 5 Table 2-2). Numbers in eastern herd units could be markedly higher than n n d numbers coun based on mod- nted el estimat that correc for sightabi tes ct ility (persona communica al ation, B. Scur rlock, Wyomi Game and Fish ing d Departme ent). Herd south and southeast of YNP (see Fig ds gure 2-4) tota aled 37,410 w an object with tive of 35,577 (see 7 Table 2-3). Elk populaation trends in Wyoming herds east, sou n h utheast, and s south of YNP are shown in Fig- P n ures 2-7, 2-8, and 2-9. 2 FIGURE 2-5 Trends in elk numbers in Montana elk management units. These E i k t EMUs are located just beyond the DSA, exce for Gravell The gray ba ept ly. fidence interva on a locally weighted scatt ands represent the 95% conf al terplot smoothing. SOURCE: MDFWP data pr M rovided to com mmittee. 26 Pre epublication Copy—Subje to Further Editorial Rev ect r vision

Geogr raphic Scope of Population and Diseas and Chang in Land Us ns se ge se FIGURE 2-6 Histogram of the elk group size dist m g tribution from the eastern p m portion of the GYA in Wyo oming. Arrows hig ghlight the few but very large elk groups. SOURCES: Cr w, S ross et al., 2013 Brennan et a 2015. 3; al., TABLE 2- Numbers of Elk in Herds East of YNP in Wyoming in 2015 -2 f E n Elk Hunt Area Total Coun nted Population Obj P bjective Posthunt Estimate Clarks For rk 2,390 3,300 4,600 Cody 4,205 4,400 6,000 y Gooseberry 2,090 2,015 2,000 Medicine Lodge L 2,130 3,000 8,216 North Bigh horn 6,610 4,350 6,610 Total 17,425 17,065 27,426 NOTE: “T Total Counted” is the total nu umber counted from the grou or air durin classificatio The “Popu und ng ons. ulation Objective” is set by the WGFD, and “P ” W Posthunt Estim mate” is statistic cally modeled and takes into account sight o tability and survey effort. y SOURCE: Personal comm munication, B. Scurlock, WG . GFD. Elk in Ida Southwes of YNP aho, st Ther are five elk managemen zones in eastern Idaho th provide habitats for GY elk (see F re k nt hat YA Figure 2-4 and Table 2-4). Th T hese units con ntain herds that seasonally migrate over relatively sh distances from r hort s low eleva anges to high elevation summer rang There is s ation winter ra her ges. some movem ment between Idaho and YNP, Grand Teton National Par (GTNP), and the Rocke , n rk a efeller Parkwa areas in W ay Wyoming. In c certain circumstaances, Idaho permits emerg p gency winter feeding of elk to prevent e k excessive mortality in drai inages that would affect herd recovery. Thhere is one el emergency winter feedi area with four feeding sites lk y ing h g near the border with Wyoming (pers b W sonal commu unication, D. C Cureton, Idah Departmen Fish and Ga ho nt ame). Prepublic cation Copy— —Subject to Fu urther Editori Revision ial 27

Revisiting Brucellosis in the Greater Yellowstone Area g i r e TABLE 2- Numbers of Elk in Herds South and Sout -3 f S theast of YNP in Wyoming i 2015 in Elk Hunt Area Total Counted C Population O Objective Posthun Estimate nt Fall Creek 3,813 4,400 4,500 Afton 1,837 2,200 1,837 Upper Green River 2,713 2,500 2,713 Piney 1,736 2,400 3,100 Jackson 11,051 11,000 11,200 Pinedale 2,081 1,900 2,081 West Green River 4,791 3,100 3,225 Hoback 1,104 1,100 1,104 Wiggins Fork 5,663 5,500 5,817 South Win River nd 2,621 2,600 – Targhee 0 200 200 Total 37,410 36,900 35,777 NOTE: “T Total Counted” is the total nu umber counted from the grou or air durin classificatio The “Popu und ng ons. ulation Objective” is set by the WGFD, and “P ” W Posthunt Estim mate” is statistic cally modeled and takes into account sight o tability and survey effort. y SOURCE: Personal comm munication, B. Scurlock, WG . GFD. FIGURE 2-7 Elk popula 2 ation trends in herds east of YNP. The gray bands represe the 95% co Y y ent onfidence inter rval on a locally weighted scatter w rplot smoothin SOURCE: WGFD data pr ng. W rovided to com mmittee. 28 Pre epublication Copy—Subje to Further Editorial Rev ect r vision

Geogr raphic Scope of Population and Diseas and Chang in Land Us ns se ge se FIGURE 2-8 Elk popul lation trends in herds south and southeast east of YNP This area also has the elk feed- n t P. k grounds. The gray band represent th 95% confidence interval on a locally weighted scatterplot smoo T ds he l y othing. SOURCE: WGFD data provided to com p mmittee. FIGURE 2-9 Elk population trends in herds the fur n rthest south of YNP. The gra bands repre f ay esent the 95% confi- dence inter on a locall weighted sca rval ly atterplot smootthing. SOURC WGFD data provided to c CE: a committee. Prepublic cation Copy— —Subject to Fu urther Editori Revision ial 29

Revisiting Brucellosis in the Greater Yellowstone Area TABLE 2-4 Elk Herds in Idaho in the GYA Idaho Elk Management Zone Count Island Park 2,512 Teton 220 Palisades 797 Tex Creek 3,885 Diamond Creek 2,352 Total 9,766 NOTE: Idaho elk management zones are listed from north to south. SOURCE: Cureton and Drew, 2015. 2.6 The Jackson Elk Herds The Jackson Herd Unit comprises most of the areas south and east of GTNP and the National Elk Refuge (NER), with three elk feedgrounds located in this area (see Figure 2-4). The Jackson elk herds winter on low elevation winter ranges, including the NER, the Gros Ventre drainage, and areas near Mo- ran in GTNP. Many of these elk move to higher elevation summer ranges across a broad area to the north, including southern YNP (Boyce, 1989; Smith and Anderson, 2001; Cole et al., 2015). The management objective determined for this area is 11,000 elk, which is based on judgment, past experience, and balance of conflicting objectives of different stakeholders. On average, there were 11,690 elk counted from 2009-2013 and 11,051 were counted in 2015 (WGFD, 2014; see Table 2-4). As many as 19,000 elk were estimated in the mid-1990s but annual harvests have reduced the population (USFWS/NPS, 2007). Herd management goals were to feed 5,000 elk on the NER, 3,500 elk in the upper Gros Ventre feedgrounds and native winter ranges east of Crystal Creek and 2,500 elk on other native winter ranges (WGFD, 2014). The number of elk on native winter ranges has decreased dramatically over the past decade (USFWS/NPS, 2007). On average 1,307 elk were harvested by 3,082 hunters per year from 2009-2013. The NPS and the Wyoming Game and Fish Commission also carry out elk reductions based on yearly recommendations in two areas just outside the east boundary of GTNP. An average of 536 Jackson herd elk have wintered in GTNP from 1989-2003. The objective is to support an average of about 356 elk in GTNP, with numbers ranging between 137 and 857 (USFWS/NPS, 2007). The NPS philosophy for national parks is to contribute to the conservation of spe- cies at larger landscape scales. However, there are no allowances for permitting elk or bison populations to exceed natural densities within GTNP, even when this would contribute to natural population levels for the larger landscape (USFWS/NPS, 2007). An elk reduction program in GTNP was authorized by Congress in 1950. Removals occur in the Fall in two hunt areas east of the Snake River but within the boundaries of GTNP and are coordinated between the NPS and WGFD (personal communication, Sue Consolo-Murphy, National Park Service, February 23, 2016). In the mid-1990s, densities of elk were 2.5-fold higher in GTNP than densities outside of GTNP, likely as a result of the relative lack of hunting inside GTNP compared to outside of GTNP (Smith and Anderson, 1996). Smith and Anderson (1996) also concluded that elk numbers inside GTNP were not being regulated through food limitation and density dependence, because they spend winter and are fed on the NER, and thus argued that hunting removals are warranted. In 2014, there were 129 wolves in 17 packs in the Jackson herd area (packs south and southwest of YNP excluding Wind River Reservation and Prospect packs) (Jimenez and Becker, 2015). As of winter of 2004, the total number of elk killed by wolves each winter in the Gros Ventre portion of the Jackson herd area was estimated to represent less than 1% of the herd (USFWS/NPS, 2007; WGFC, 2007). Wolves preyed incidentally on the NER until 2004/2005; 18 elk were killed in 2004/2005 and 63 were killed in 2005/2006 (USFWS/NPS, 2007). Grizzly bear numbers were positively correlated with calf:cow ratios in this area, more so in unfed than fed elk (Foley et al., 2015). 30 Prepublication Copy—Subject to Further Editorial Revision

Geographic Scope of Populations and Disease and Change in Land Use 2.7 Elk Feedgrounds Currently, 22 elk feedgrounds are maintained in Wyoming by the WGFD, independently of the NER. Feedgrounds are mostly located adjacent to active cattle allotments within Bridger-Teton National Forest (BTNF) and along boundaries between U.S. Forest Service (USFS) lands and private lands. Bienen and Tabor note two reasons for feeding, including “keeping brucellosis infected elk from foraging on cat- tle ranches, and maintaining consistently higher numbers of elk than the available range could support, which satisfies hunters and outfitters and brings revenue to the state” (Bienen and Tabor, 2006). The Wy- oming Game and Fish Department states three reasons for maintaining the feedgrounds: (1) to prevent depredation on stored crops, (2) to prevent elk-livestock comingling, and (3) to reduce winter elk mortali- ty (WGFD, 2011). However, there is some disagreement about the benefits of feedgrounds (Bienen and Tabor, 2006). In the absence of feeding, elk disperse and give birth alone which limits disease transmis- sion. Additionally, there is concern that the mortality from an epidemic of chronic wasting disease that could be facilitated by high elk densities on feedgrounds would exceed any losses resulting from reducing or eliminating feeding. From 1982-1987, the number of elk counted on the feedgrounds, including the NER, increased from 17,770 to 20,145, but since then the number has been relatively stable in the range of 20,000 to 26,000 (Cross et al., 2010a). From 1998-2013, the NER has fed 5,000-8,000 elk (USFWS/NPS, 2007) which means that approximately 15,000-18,000 elk have been fed on the other feedgrounds since 1998. Since 1998, the WGFD tried to reduce large elk aggregations on several feedgrounds by distributing food across a broader area and by stopping feeding earlier in the year (Cross et al., 2013). Targeted elk hunts have been implemented in some areas of southwestern Montana and western Wyoming to disperse large groups, move them away from cattle, and reduce population sizes. In theory, supplemental feeding would reduce negative effects of dry growing seasons and severe winters on forage availability, which would then result in increased elk reproduction and survival (Foley et al., 2015). However, one study found no evidence that feedgrounds affected midwinter calf:cow ratios (Foley et al., 2015). Calf:cow ratios of fed elk were more strongly correlated with environmental factors (snow and summer rainfall), while calf ratios of unfed elk were more strongly correlated with predator densities, particularly bear density. In contrast, an earlier study found that survival of calves supplemen- tally fed in winter exceeded survival of calves not fed (Smith and Anderson, 1998). Population growth is also affected by juvenile and adult survival (Lubow and Smith, 2004). Howev- er, variation in juvenile survival is primarily affected by environmental conditions, particularly snowpack and duration of winter, and is little affected by feeding (Smith and Anderson, 1998). Also, female elk that fed on feedgrounds had negligibly higher survival rates than unfed elk, and any differences in survival due to feeding were due to effects on older animals which have lower reproductive values (Foley et al., 2015). Supplemental feeding can alter the seasonal migrations of elk (Jones et al., 2014). Fed elk migrate shorter distances, arrive on summer ranges later, and depart from summer ranges earlier than unfed elk. Feeding disrupts the migration of fed elk from the timing of spring green-up, and it decreases the time elk spend on summer range by 26 days, thereby reducing access to quality forage (Jones et al., 2014). If sup- plemental feeding were phased out, elk might make greater use of summer ranges to at least partially compensate for the loss of feed. Supplemental feeding of elk also increases dense aggregations which in turn increases stress levels; this has been detected through increases in glucocorticoid, a metabolite asso- ciated with stress that has been hypothesized to reduce immune function and increase disease susceptibil- ity (Forristal et al., 2012). Relocating, reducing, or eliminating feedgrounds are options that have previ- ously been considered but not pursued by WGFD in their Brucellosis Area Management Plans (WGFD, 2011). Reasons cited by WGFD for not pursuing these options include land availability constraints with relocating feedgrounds (including permitted grazing allotments) and lack of support from various constit- uencies (agriculture, land management agencies, sportsmen) for reducing or eliminating feedgrounds. However, as part of a Target Feedground Project, major reductions in the length of the feeding season Prepublication Copy—Subject to Further Editorial Revision 31

Revisiting Brucellosis in the Greater Yellowstone Area have already occurred at certain feedgrounds since 2008, and minor reductions have occurred at other feedgrounds since 2009. 2.8 The National Elk Refuge In 1912, the NER was created as a place for supplemental elk feeding that would mitigate the loss of natural winter range and minimize impacts to livestock operations. Historically, elk moved longer dis- tances to areas, including the upper Gros Ventre Basin, Idaho, the Green River area, and in severe win- ters, the Red Desert (Murie, 1951; Cole, 1969; Boyce, 1989; Cromley, 2000; USFWS/NPS, 2007). Re- cently, human settlement and conversion of winter range to livestock grazing areas has shortened migration routes and caused elk to remain in Jackson Hole (USFWS/NPS, 2007). Supplemental feeding increases the nutritional status1 of 68% to 91% of the Jackson elk herd and reduces winter weight loss, particularly in severe winters (Wisdom and Cook, 2000; USFWS/NPS, 2007). The number of elk fed on the NER has varied from about 5,000-11,000 between 1971-1997, and from 5,000-8,000 between 1998-2013. The Bison and Elk Management Plan calls for a reduction to 5,000 elk on the NER (USFWS/NPS, 2007). The population objective of 5,000 elk for the NER is distinct from the population objective of 11,000 for the entire Jackson Herd Unit set by the WGFD. The herd objective for the NER is set at a level that is in line with USFWS policy for refuges to contribute to natural popula- tion densities and natural levels of variation at larger landscape scales, especially when habitat has been lost in the surrounding landscape or ecosystem (USFWS/NPS, 2007). Given concerns over the negative impacts of supplemental feeding on brucellosis transmission, it is pertinent to determine how many elk could be supported on native ranges if feedgrounds were to be phased out. In modeling the number of elk that could be supported across an area corresponding to the Jackson Herd Unit, Hobbs and colleagues (2003) used a “Forage Accounting Model” to estimate forage production, snow cover, and resulting forage availability for different habitat types. The model indicated that supplemental feeding is necessary to support current numbers of elk in winters with above average snowpack, but supplemental feeding far overcompensates for the loss of winter range in winters that have average or below average snowpack (Hobbs et al., 2003). Without supplemental feeding, about half as many elk could be supported compared to current numbers in winters with average snowpack. However, reductions in forage availability in severe winters are natural occurrences. The model indicated that habi- tat removals due to human settlements and livestock grazing have had negligible effects on forage availa- bility (Hobbs et al., 2003). According to the 2007 elk and bison management plan, a long-term goal is to implement a variety of actions to transition from intensive supplemental winter feeding on the NER to a greater reliance on free- standing forage (USFWS/NPS, 2007). This would need to be carried out with objective criteria and adap- tive management actions that would be developed in collaboration with the WGFD. 3. CHANGES IN LAND USE AND CONSEQUENCES FOR ELK Changes in land ownership in areas outside of YNP have affected elk distributions and the ability of state wildlife authorities to manage elk populations. In three elk hunting districts just north of YNP, there has been a shift in property ownership to more owners who are interested in natural amenities and who exclude hunters in order to support elk for their own enjoyment, which consequently has created refugia for elk (Haggerty and Travis, 2006). In those three hunting districts (HDs 313, 314, and 317), 18% of the winter range is privately owned in one district (HD 313) while 71% and 46% of winter range is privately owned in the other two districts (HD 314 and 317), respectively (Haggerty and Travis, 2006). The MDFWP has been able to utilize a combination of general and late season hunts to achieve population 1 Nutritional status indicates the degree to which an animal’s nutritional requirements are being met through for- age intake. Nutritional status will decrease when requirements are not being met, and it will increase when intake exceeds requirements. 32 Prepublication Copy—Subject to Further Editorial Revision

Geographic Scope of Populations and Disease and Change in Land Use targets in HD 313, but this has proven more difficult in HDs 314 and 317, because the lands are “out of administrative control” (Haggerty and Travis, 2006). Similar and even more pervasive land ownership changes have taken place in the Paradise Valley (north of the Northern Yellowstone Management Unit) and in the Madison Valley (west of the Park). These land use and land ownership conversions could have contributed to a much larger fraction of the northern elk herd now being found outside of YNP in the win- ter and in larger and denser groups than previously found. More people are also settling across the GYA. From 1990-2010, the population of census blocks in and near the GYA increased nearly 50% with much of that growth occurring in rural home development (McIntyre and Ellis, 2011). From 1970-1999, the population in the GYA increased by 58%, with rural areas increasing by 350% due to exurban housing densities, demonstrating that developed land in the GYA is increasing faster than the rate of population growth (Gude et al., 2006). The GYA consists of the 145,635 km2 of land, with 32% privately owned, 32% managed by the USFS, 19% by the Bureau of Land Management (BLM), and 7% managed by the NPS (Gude et al., 2007). Using the current rates of popula- tion growth to predict future land use scenarios and their potential impact on biodiversity, Gude and col- leagues (2007) predicted that 10% of elk winter range and 24% of wildlife migration corridors would be affected in 2020. With many core winter ranges north and northwest of YNP in private ownership, MDFWP has iden- tified a number of management challenges. These challenges arise from a large fraction of the elk popula- tion not being available to hunters due to reduced access to public land and adjacent private land, increas- es in landowners who have less interest in allowing elk hunting, and elk that have shifted onto privately- owned lands during the hunting season (Proffitt et al., 2010b). However, as of the writing of this report, a proposed option in the Montana Fish and Wildlife Commission's Brucellosis 2017 Annual Work Plan would allow for landowners in the Red Lodge area, which is outside the DSA, to request that a very lim- ited number of potentially infected elk (no more than 10) be culled to prevent contact with livestock (French, 2016). Changes in land use can also potentially increase the risk of elk-cattle contact. Across the GYA, scrub/shrub and grasslands are the predominant land cover types on private lands (35% and 26% respec- tively), and are the types most likely to be used for livestock grazing (McIntyre and Ellis, 2011). Winter ranges for large mammals (elk, mule deer, pronghorn antelope) also occur primarily on scrub/shrub (9,804 km2) and grassland/herbaceous (7,001 km2) land cover types. Consequently, increased develop- ment of private lands on land cover types that are used by both livestock and large mammalian wildlife (including elk) could result in an increasing number of wildlife finding refugia from hunting on exurban land holdings (Haggerty and Travis, 2006; Gude et al., 2007; McIntyre and Ellis, 2011). Increased elk- livestock interaction could occur in some areas where elk prefer private lands with livestock over lands where public hunting occurs (Proffitt et al., 2010b). Although exurban development could reduce elk- livestock interactions by reducing livestock numbers, this could be offset by increased elk-elk transmis- sion due to denser concentrations of elk on exurban refugia. 4. BISON POPULATIONS AND DISTRIBUTIONS 4.1 The Yellowstone Bison Herds The Yellowstone bison population consists of two herds: a central herd and a northern herd, with some intermixing between them (Gates et al., 2005; Olexa and Gogan, 2007). The range for the central herd includes the Hayden and Pelican Valleys in the east, across to the Firehole Valley and the Madison River Valley in the west (see Figure 2-10). The range for the northern herd is at lower elevations, and in- cludes the Lamar River Valley in the east and the Gardiner Basin in the west. Under the Interagency Bi- son Management Plan, bison are allowed to use habitats outside the northern and western boundaries of YNP (Zone 2 and Eagle Creek, see Figure 2-10). Prepublication Copy—Subject to Further Editorial Revision 33

Revisiting Brucellosis in the Greater Yellowstone Area g i r e FIGURE 2-10 Bison ran distribution conservation areas, and Zo 2 bison tol 2 nge n n one lerance areas. S SOURCE: Wa allen et al., 2015. In 19 the total bison popula 966, ation was 366 and had been managed th 6 n hrough period herd reduc dic ctions. In 1968, a natural regu ulation policy was adopted for bison and elk, with th hypothesis being that po d d he opula- tions wou naturally achieve a dyn uld a namic equilibr rium with forrage producti without hu ion uman interveention. The bison population grew steadily from 1968-1995 (see Fig n y gure 2-11). T first remo The ovals outside YNP boundarie occurred in 1992, with considerable numbers of bison remov in winters of 1994-199 In es n ved s 98. 2006, the population grew in size to 5,015 animals. Bison hunting was first allowed outside the YNP g d boundarie in 2005-2006, and a sub es bstantial numb of bison w ber were hunted i the followi years. Du pri- in ing ue marily to management removals fro 2005-200 the total p t om 08, population wa reduced to less than 3,0 in as 000 2009. Sin that time, the total biso population has increase to nearly 5,000 in 2014, which incr nce on n ed reases the popula ation average to about 4,00 over the lo e 00 Notably, most of this increa occurred in the onger-term. N t ase northern herd that has more than doubled in siz since 2008 meanwhile, the central herd has rem h d ze 8; mained nearly con nstant in size In 2015, YNP managers recommend removing or hunting a e. Y s ded g approximately 900 y bison per year in the two following winters to achieve a pop t g a pulation targe of 3,500, a recommend in et as ded the Intera agency Bison Management Plan (IBMP (Geremia e al., 2014a). The number of bison tha can t P) et at actually be removed depends on th number tha cross the Y b d he at YNP boundary however, i is realistic to as- y; it sume suff ficient numbe would emi ers igrate given th current siz of the popu he ze ulation. 34 Pre epublication Copy—Subje to Further Editorial Rev ect r vision

Geogr raphic Scope of Population and Diseas and Chang in Land Us ns se ge se FIGURE 2-11 Bison cou and annua removals, northern and cen 2 unts al ntral herds. SOU URCE: Gerem et al., 2014b mia b. Biso migrate sea on asonally alon elevational gradients: m ng l moving from h higher elevati summer r ion ranges to lower elevations du uring autumn through win n nter, and retu urning to summmer ranges in June (Mea agher, 1989; Bjoornlie and Gar rrott, 2001; Bruggeman et al., 2009; Pl B t lumb et al., 2009). Migrati to lower e ion eleva- tions is pr rimarily drive by earlier snowfall and greater snow depths at h en d w higher elevatio in autum and ons mn early winnter. As the bison populati increased more bison began migra b ion d, n ating earlier to lower elev vation winter rannges for bette access to food resources (Meagher, 1989; Brugge er fo s 2009; Plumb et al., eman et al., 2 2009). In the spring, bison progres b ssively migra to higher elevations, f ate following the progressive snow e melt and green-up with increasing elevation. g h e Prepublic cation Copy— —Subject to Fu urther Editori Revision ial 35

Revisiting Brucellosis in the Greater Yellowstone Area Bison movements out of YNP are driven by a combination of density and snow conditions that re- duce forage availability. Density dependent dispersal has been observed in many animal populations (Owen-Smith, 1983; Pulliam, 1988). Since 1998, more than 6,000 bison have been removed from the two dispersal areas outside the northern and western boundaries during their annual winter migrations to lower elevations, and the total population has been kept in the 3,000-5,000 range since 2002. However, the northern range has now become a dispersal area for the central herd, numbers in the northern herd have more than doubled, and animals crossing the northern boundary are coming from the central herd. An analysis of bison removals versus population size showed that there were generally few remov- als when the population was below 3,000. Above the threshold of 3,000, bison removals markedly in- creased and removals were highly correlated with population size when snow water equivalent was above 17 inches. It was also suggested that exceptionally large numbers of bison would leave YNP when the snow pack melts and refreezes to create an ice layer, as occurred in the winter of 1996-1997. A more re- cent analysis using data through 2008 indicated that in average winters, most movements outside YNP would be minimal if population sizes are kept <3,500 in the central herd and <1,200 in the northern herd (Geremia et al., 2009). Migration beyond the northern boundary is affected by herd size, snow water equivalent, and forage biomass while migration beyond the western boundary is less influenced by these variables (Geremia et al., 2011). Kilpatrick and colleagues (2009) predicted that with 7,000 bison and av- erage snowfall, more than 1,000 bison would leave in YNP 74% of the winters; with 3,000 bison and av- erage snow, over 1,000 bison would emigrate in 9% of the winters; and with severe snow, more than 1,000 bison would leave in 25% of the winters. In the past three decades, the increases in bison populations and bison movements outside YNP have been partly attributed to more favorable conditions for bison movement and resultant range expansions. Although road grooming for snowmobiles and coaches could increase population growth and facilitate movements and range expansion (Meagher, 1993), more recent analyses have concluded that road groom- ing has not affected range expansion or population growth (Gates et al., 2005; Bruggeman et al., 2007). Bison have increasingly used road corridors to travel through certain landscape bottlenecks, such as can- yons that connect the central and the northern herd ranges (Gates et al., 2005; Bruggeman et al., 2006, 2007, 2009). The resultant increased connectivity between the central and northern herds has likely con- tributed to increased numbers of animals exiting the northern boundary. Bison population growth rate decreases at higher population densities (Fuller et al., 2007). This is because bison become increasingly resource limited at higher population densities, despite the added re- sources resulting from range expansion as was seen in the 1980s and 1990s. Despite the declining popula- tion growth rate at higher densities and removals at the boundaries, population growth rates have re- mained positive, even at high densities. The use of an ecosystem model to estimate food limited carrying capacity can be useful for predict- ing population dynamics (Coughenour, 2005; Plumb et al., 2009). Coughenour (2005) predicted that a mean bison population size of 6,000 could be sustained at food limited carrying capacity with no remov- als at the boundaries. This is in comparison to the actual population of 5,000 where more bison could the- oretically be supported by the forage base, however bison are intolerant of increased levels of competition and nutritional stress at higher densities and prefer to migrate beyond the designated dispersal areas to maintain adequate nutritional status. Also, elk compete with bison for forage due to overlapping diets and habitat and bison numbers are affected by elk abundance (Coughenour, 2005). The decrease in elk on the northern elk winter range could therefore have contributed to increased numbers of bison. 4.2 The Jackson Bison Herd The Jackson bison herd is jointly managed by the NER, GTNP, WGFD, BTNF. Bison were first in- troduced into GTNP near Moran in 1964 and were allowed to free range in 1969, then establishing well- defined seasonal movement patterns in GTNP. However, since the winter of 1975/76, most of the herd has wintered on the NER. In 1980, bison discovered the NER feedlines and subsequently the herd greatly increased in size. Bison were initially culled or hunted, but since 1990 no reductions have taken place. 36 Prepublication Copy—Subject to Further Editorial Revision

raphic Scope of Population and Diseas and Chang in Land Us Geogr ns se ge se The WGF reinitiated hunting in 1998 outside the NER and GTNP; how FD d 1 d wever, few ha been kille be- ave ed cause most habitats ar inside the NER or GTN In 1990, the Jackson bison popula re NP. ation was appproxi- mately 11 in 1998, it increased to about 43 and in 20 10; 30; 006, it has iincreased fur rther to abou 950 ut (USFWS/ /NPS, 2007). The Bison an Elk Manag nd gement Plan ((USFWS/NPS 2007) calls for a reduct S, s tion to 500 bison and 5,000 el During fee n lk. eding operatio for elk on the NER, th bison are fe in order to min- ons n he fed o imize disrruptions with the elk feed h ding operations. After fee eding is disco ontinued in la winter or early ate spring, th bison herd moves north of the NER to spring ra he d h R anges, then mmoves further north to su r ummer ranges on the east side of GTNP. Ca n alving occurs on both the s spring and summmer ranges. FIGURE 2-12 Bison poopulation grow rates versu population sizes in the pr wth us revious year, n northern and c central herds. SOU URCE: Geremi et al., 2014b ia b. Prepublic cation Copy— —Subject to Fu urther Editori Revision ial 37

Revisiting Brucellosis in the Greater Yellowstone Area 5. LIVESTOCK There are approximately 450,000 cattle and calves in the GYA comprising those in Bonneville, Car- ibou, Franklin, Fremont, and Teton counties in Idaho; Gallatin, Madison, and Park counties in Montana; and Lincoln, Park, Sublette, and Teton counties in Wyoming (NASS, 2011; Schumaker et al., 2012). Ap- proximately 85% of the operations are cow-calf producers with open range grazing in summer and pas- ture supplemented with hay during the winter. Within the DSAs, there are 296 herds in Montana, 242 in Wyoming, and 191 in Idaho (USDA-APHIS, 2014). Since 1998, cattle operations immediately adjacent to YNP have been reduced as part of the IBMP. Private lands just north of YNP have been acquired by the USFS for inclusion into the northern bison management area. In 2006, there were 266 cattle in four herds in winter and 677 in nine herds in spring in the northern bison management area (Kilpatrick et al., 2009). More recently, in the northern bison man- agement area, there were just two small (25 each) cattle operations (USDA-APHIS, 2014). In the IBMP western bison management area, there were no cattle in winter and 686 cattle in nine herds in spring (Kil- patrick et al., 2009). Recently, it was reported that there were 4 seasonal operators (no year-around opera- tions) with approximately 600 cow-calf pairs utilizing the western management area during summer after June 15 (USDA-APHIS, 2014). Due to the reduced numbers of cattle and management operations that maintain temporal and spatial separation from bison, few cattle have any exposure to infected YNP bison (USDA-APHIS, 2014). Originally, GTNP had 29 permittees grazing approximately 4,320 animals on 67,640 acres inside of GTNP. The number of permittees has decreased to two as a result of permits expiring and ranches ceasing to operate (USFS/NPS, 2007). The two remaining permittees graze on three grazing allotments that are inholdings: one with 525 cattle animal unit months (AUMs) permitted (264 cattle present) and the others with only horses. Just outside the GTNP are three ranches with 5514 cow-calf AUMs on two ranches that seasonally move animals from one area to another, and one ranch with 60 breeding stock permitted (55 cattle present) (personal communication, S. Consolo-Murphy, NPS, 2015). In the three counties in Wyoming at the southern end and just beyond the GYA (Lincoln, Sublett, and Sweetwater Counties), there are approximately 105,000 cattle and 500 producers (personal communi- cation, B. Schumaker, University of Wyoming, 2015). These counties contain portions of 17 WGFD elk herd units and 15 of the 22 feedgrounds not including the NER. In conducting a cost-benefit analysis of various brucellosis management options, a risk map was produced of elk-cattle interactions for this tri- county area (Kauffman et al., 2013), which is a somewhat preliminary approach, but one that has consid- erable potential for use in the future. While there are many legally designated grazing allotments throughout the GYA (see Figure 2-13), many of them are not active. The committee was unable to locate maps of all active versus non-active allotments throughout the GYA. However, the Bridger-Teton National Forest (BTNF) provided the com- mittee with information showing permitted livestock numbers, turn-on and turn-off dates, head-months and animal unit months (AUMs) for each allotment (personal communication, T. O’Conner, USFS, 2016). In BTNF, there are 63 active grazing allotments with approximately 99,000 permitted cattle (see Figure 2-14). A total of 34,337 livestock, 110,892 head-months, and 135,603 AUMs are permitted. The permits included mature cows with a nursing calf, yearlings, and bulls. Turn-on dates varied from June 1 to July 15 and turn-off dates generally varied from September 15 to October 15. In Idaho, there are cur- rently 163 resident cattle herds within the DSA with approximately 15,000 head; there are also 80 season- al herds that use USFS, BLM, and private lands with approximately 16,000 head (personal communica- tion, B. Barton and D. Lawrence, Idaho Department of Agriculture, 2015). Although livestock numbers have been reduced or closely managed immediately adjacent to the na- tional parks, there are large areas of private lands and grazing allotments that have considerable overlap with elk throughout the GYA. 38 Prepublication Copy—Subject to Further Editorial Revision

raphic Scope of Population and Diseas and Chang in Land Us Geogr ns se ge se FIGURE 2-13 Grazing allotments thro 2 a oughout the GY Each of the drawn polygo is an allotm YA. e ons ment, and the c current use of man allotments across the entire region were not easily acce ny a e n essible. SOURC CES: Bureau o Land Manag of gement (2014) and U.S. Forest Service (2008, 2009, 2015). d 2 6. IMP PLICATION OF CHAN NS NGING CLIM MATE FOR ELK AND B BISON Clim change in the GYA has implicatio for elk an bison numb mate h ons nd mbers and disttributions, and thus d brucellosi in the GYA A recent an is A. nalysis of his storic climate data conclud that over the past 100 years ded minimum temperatures have increa m s ased 2.9oF and maximum t d temperatures have increase 1.2oF (Nor ed rthern Rockies Adaptation Pa A artnership, 20 014). Using cl limate model outputs from the Coupled Model Inter l m d rcom- parison Pr roject, maxim mum temperat ture in the GY is expect to rise 5-1 oF and min YA ted 10 nimum temperature is projecte to rise 7-12oF, with win maximum temperature predicted to rise above 32oF in mid-ce ed 2 nter m e o 2 entury Prepublic cation Copy— —Subject to Fu urther Editori Revision ial 39

Revisiting Brucellosis in the Greater Yellowstone Area g i r e and summ temperatu mer ures predicted to rise by nearly 5oF by mid-century and nearly 1 oF by the e of d n y y 10 end edictions for precipitation are uncertain but there co the centur (Littell et al., 2011). Pre ry a n, ould be a slig in- ght crease. Warming temp W peratures in th northern Rocky Mount he R tains is assoc ciated with ea arlier spring ssnow- melt, war rmer summer and longer growing se rs, easons (Romm and Turn 2015). Sp me ner, pring and suummer temperatu will rise 8-10oF by mi ures id-century, with increased frequency of hot, dry sum w d mmers (West terling et al., 2011). Snowpac in the GY have con cks YA nsistently decclined due to increased te o emperatures, and a long-term forecast in th GYA calls for less snow (Tercek et al., 2015). Th conclusion is based on anal- m he s w his n n yses showwing that temp eases are the primary caus of decrease snowpack, and that tem perature incre se ed , mpera- tures are continuing to trend upward Another projection cal for a 32% reduction in snowpack in areas c ds. p lls ions and a 56% reduction a higher elev typical of elk habitats at mid elevati f a at vations (Lapp et al., 2005; Creel p and Creel, 2009). FIGURE 2-14 Active U.S. Forest Ser U rvice grazing allotments in Bridger-Teton National For n rest. SOURCE: Data provided by U.S. Forest Service Bridge b S er-Teton Nation Forest. nal 40 Pre epublication Copy—Subje to Further Editorial Rev ect r vision

Geographic Scope of Populations and Disease and Change in Land Use Reduced winter snowpack will affect elk and bison by increasing winter forage intake and by caus- ing spring snowmelt and green-up to occur earlier. Reduced snowpack may also reduce the energetic costs of foraging and traveling in winter. As a result of greater forage intake and reduced stress, popula- tion growth rates are likely to increase. An empirical elk population model predicted that warmer winters could raise equilibrium population size in Rocky Mountain National Park elk by 50-100% depending on whether summers are drier or wetter (Wang et al., 2002). Using an empirical population model driven by climate model outputs, it is predicted that Montana elk populations will increase substantially due to re- duced snowpack (Creel and Creel, 2009). Similarly, the annual population growth rate of bison in the central YNP herd was negatively corre- lated with snowpack, but not so for the northern herd likely due to deeper snow at higher elevations in central YNP than northern YNP (Fuller et al., 2007). As previously discussed in this chapter, bison movements in winter to lower elevations (including areas outside YNP) are driven by a combination of increased animal density and increased snowpack. Thus, it is likely that reduced snowpack will reduce bison outmigration from YNP, but this could be offset by increased population size unless the population is managed. Increased population growth rate could also lead to increased numbers being removed out- side the YNP boundary by management actions. Conversely, reduced snowpack will likely cause earlier migrations upslope in the spring due to earlier green-up, resulting in a shorter duration of bison at low elevations outside YNP. Temperature and precipitation interactively affect plant growth and thus forage availability. In- creased spring temperatures will result in earlier green-up and growth, but increased summer temperatures in water-limited environments can lead to increased evapotranspiration, reduced soil moisture, reduced growth, earlier curing of forage, and thus reduced forage quality. During the dry period of 1989-2009 in the GYA, spring-summer temperatures were warmer and there was reduced spring precipitation, leading to an increased rate and shorter duration of green-up (Westerling et al., 2006; Middleton et al., 2013a). The dry conditions resulted in less green forage and lower pregnancy rate, and a mismatch between time of green forage availability and the period of lactation could also lower recruitment rate, presumably through reduced calf survival (Post and Forchhammer, 2008; Middleton et al., 2013a). Overall, the positive effects of reduced snowpack and the negative effects of warmer temperatures and increased dryness could counteract one another. The net outcome can most likely be predicted with process-based models. Models of plant growth and snowpack that represent the effects of water, tempera- ture, and snowpack on plant productivity, time of green-up, and time of senescence could be employed to predict future patterns of forage availability seasonally and across the landscape. Such models can be linked to models of animal distributions in response to changing distributions of snow, forage, and land use, and process-based population dynamics models that consider the effects of forage availability on an- imal nutritional status and consequent rates of reproduction and survival (e.g., Coughenour, 2005). The implications for brucellosis arise from changes in predicted elk numbers and distributions in relationship to livestock numbers and potential elk management actions. 7. SUMMARY With elk now known to be a primary source of B. abortus transmission in the GYA, the scope and dynamic complexity of brucellosis in the GYA has expanded. Whereas bison are primarily confined to YNP or just outside its immediate borders, many tens of thousands of elk are spread across a very large and heterogeneous area. Elk are likely a reservoir of brucellosis independent of bison. Elk populations in the GYA have increased for the most part, and elk now occur in larger aggregations than in the past. The change in elk numbers and distributions is in part due to land use changes, including land acquisitions by owners who discourage or prohibit access by hunters, which then creates refugia from hunting offtake and leads to elk aggregations. Also, large numbers of elk continue to be artificially fed in winter in the south- ern GYA. Despite recognition by management agencies that feeding contributes to B. abortus transmis- sion and that it would be desirable to phase out feeding, this goal remains elusive due to extensive habitat overlap with livestock operations and questionable assertions that feeding is necessary to maintain abun- Prepublication Copy—Subject to Further Editorial Revision 41

Revisiting Brucellosis in the Greater Yellowstone Area dant elk populations. These major factors have contributed to the sustainability of elk populations as a reservoir for brucellosis. The bison population has also increased, which has also shifted the distribution of bison across the landscape. Bison are moving from central YNP to northern YNP, and consequently, the northern herd segment has increased in size. Most of the bison exiting YNP do so at the northern boundary, with more exiting when snow is deeper and the population is larger, and there are efforts to manage the bison popu- lation through opportunistic removals at the YNP boundary. Northern YNP has shifted from being elk- dominated to bison-dominated. Under the Interagency Bison Management Plan, bison have been success- fully contained in designated dispersal areas just outside the YNP boundary. The dispersal area has been enlarged, and bison have also been kept separated from livestock. REFERENCES Barber-Meyer, S.M., L.D. Mech, and P.J. White. 2008. Elk Calf Survival and Mortality Following Wolf Restoration to Yellowstone National Park. Wildlife Monographs 169. The Wildlife Society. Barmore, W.J., Jr. 2003. Ecology of Ungulates and Their Winter Range in Northern Yellowstone National Park: Research and Synthesis 1962-1970. Yellowstone Center for Resources. Yellowstone National Park, WY. Bienen, L., and G. Tabor. 2006. Applying an ecosystem approach to brucellosis control: Can an old conflict between wildlife and agriculture be successfully managed? Frontiers in Ecology and the Environment 4:319-327. Bjornlie, D.D., and R.A. Garrott. 2001. Effects of winter road grooming on bison in Yellowstone National Park. Journal of Wildlife Management 65:560-572. Boyce, M.S. 1989. The Jackson Elk Herd: Intensive Wildlife Management in North America. Cambridge, UK: Cambridge University. Brennan, A., P.C. Cross, S. Creel, and P. Stephens. 2015. Managing more than the mean: Using quantile regression to identify factors related to large elk groups. Journal of Applied Ecology 52:1656-1664. Bruggeman, J.E., R.A. Garrott, D.D. Bjornlie, P.J. White, G.R. Watson, and J. Borkowski. 2006. Temporal variabil- ity in winter travel patterns of Yellowstone bison: The effects of road grooming. Ecological Applications 16:1539-1554. Bruggeman, J.E., R.A. Garrott, P.J. White, F.G.R. Watson, and R. Wallen. 2007. Covariates affecting spatial varia- bility in bison travel behavior in Yellowstone National Park. Ecological Applications 17:1411-1423. Bruggeman, J.E., P.J. White, R.A. Garrott, and F.G.R. Watson. 2009. Partial migration in central Yellowstone bison. Pp. 217-235 in The Ecology of Large Mammals in Central Yellowstone: Sixteen Years of Integrated Field Studies, R.A. Garrott, P.J.K. White, and F.G.R. Watson, eds. San Diego, CA: Elsevier. BLM (Bureau of Land Management). 2014. Grazing Allotment Boundaries. Available online at https://catalog.data. gov/dataset/grazing-allotment-boundaries (accessed May 18, 2017). Cole, E.K., A.M. Foley, J.M. Warren, B.L. Smith, S.R. Dewey, D.B. Brimeyer, W.S. Fairbanks, H. Sawer, and P.C. Cross. 2015. Changing migratory patterns in the Jackson elk herd. Journal of Wildlife Management 79:877- 886. Cole, G.F. 1969. The Elk of Grand Teton and Southern Yellowstone National Parks. Research Report GRTE-N- 1.Washington, DC: National Park Service. Coughenour, M.B. 1994. Elk carrying capacity on Yellowstone’s northern elk winter range: Preliminary modeling to integrate climate, landscape, and elk nutritional requirements. Pp. 97-112 in Plants and Their Environments: Pro- ceedings of the First Biennial Scientific Conference on the Greater Yellowstone Ecosystem, September 16-17, 1991, Mammoth Hot Springs, D. Despain, ed. Technical Report NPS/NRYELL.NRTR-93/XX. USDI/NPS. Denver, CO: U.S. National Park Service, Natural Resources Publication Office. Coughenour, M.B. 2005. Spatial-dynamic Modeling of Bison Carrying Capacity in the Greater Yellowstone Ecosys- tem: A Synthesis of Bison Movements, Population Dynamics, and Interactions with Vegetation. Natural Re- source Ecology Laboratory, Colorado State University, Fort Collins, CO. Coughenour, M.B., and F.J. Singer. 1996. Yellowstone elk population responses to fire: A comparison of landscape carrying capacity and spatial-dynamic ecosystem modeling approaches. Pp. 169-180 in The Ecological Impli- cations of Fire in Greater Yellowstone, J. Greenlee, ed. Fairfield, WA: International Association of Wildland Fire. Creel, S., and M. Creel. 2009. Density dependence and climate effects in Rocky Mountain elk: An application for regression with instrumental variables for population time series with sampling error. Journal of Animal Ecol- ogy 78:1291-1297. 42 Prepublication Copy—Subject to Further Editorial Revision

Geographic Scope of Populations and Disease and Change in Land Use Creel, S., and J.A. Winnie. 2005. Responses of elk herd size to fine-scale spatial and temporal variation in the risk of predation by wolves. Animal Behaviour 69:1181-1189. Cromley, C. 2000. Historical elk migrations around Jackson Hole, Wyoming. Pp. 53-65 in Developing Sustainable Management Policy for the National Elk Refuge, Wyoming, T. W. Clark, D. Casey, and A. Halverson, eds. Yale School of Forestry and Environmental Studies Bulletin 104. New Haven: Yale University. Cross, P. 2013. Northern Yellowstone Cooperative Wildlife Working Group 2012 Annual Report (October 1, 2012- September 30, 2012). Available online at http://www.fedgycc.org/wp-content/uploads/2015/06/2012NYCWW GFnlRpt.pdf (accessed January 4, 2017). Cross, P.C., D.M. Heisey, B.M. Scurlock, W.H. Edwards, M.R. Ebinger, and A. Brennan. 2010a. Mapping brucello- sis increases relative to elk density using hierarchical Bayesian models. PLoS One 5:e10322. Cross, P.C., E.K. Cole, A.P. Dobson, W.H. Edwards, K.L. Hamlin, G. Luikart, A.D. Middletown, B.M. Scurlock, and P.J. White. 2010b. Probable causes of increasing brucellosis in free-ranging elk of the greater Yellowstone ecosystem. Ecological Applications 20:278-288. Cross, P.C., E.J. Maichak, A. Brennan, B.M. Scurlock, J. Henningsen, and G. Luikart. 2013. An ecological perspec- tive on Brucella abortus in the western United States. Revue Scientifique et Technique Office International des Epizooties 32:79-87. Cureton, D., and M. Drew. 2015. Brucellosis and Elk in Idaho. Presentation at the Second Committee Meeting on Revisiting Brucellosis in the Greater Yellowstone Area, September 15, 2015, Moran, MT. Eberhart, L.L., P.J. White, R.A. Garrott, and D.B. Houston. 2007. A seventy-year history of trends in Yellowstone’s northern elk herd. Journal of Wildlife Management 71:594-602. Evans, S.B., L.D. Mech, P.J. White, and G.A. Sargeant. 2006. Survival of adult female elk in Yellowstone following wolf recovery. Journal of Wildlife Management 70:1372-1378. Foley, A.M., P.C. Cross, D.A. Christianson, B.M. Scurlock, and S. Creel. 2015. Influences of supplemental feeding on winter elk calf:cow ratios in southern Greater Yellowstone Ecosystem. Journal of Wildlife Management 79:887-897. Forristal, V.E., S. Creel, M.L. Taper, B.M. Scurlock, and P.C. Cross. 2012. Effects of supplemental feeding and aggregation on fecal glucocorticoid metabolite concentrations in elk. Journal of Wildlife Management 76:694- 702. French, B. 2016. Landowners southeast of Red Lodge will get help keeping elk away. Billings Gazette, October 14, 2016. Fuller, J.A., R.A. Garrott, and P.J. White. 2007. Emigration and density dependence in Yellowstone bison. Journal of Wildlife Management 71:1924-1933. Garrott, R.A., L.L. Eberhardt, P.J. White, and J. Rotella. 2003. Climate-induced variation in vital rates of an unhar- vested large-herbivore population. Canadian Journal of Zoology 81:33-45. Garrott, R.A., J.A. Gude, E.J. Bergman, C. Gower, P.J. White, and K.L. Hamlin. 2005. Generaling wolf effects across the Greater Yellowstone Area: A cautionary note. Wildlife Society Bulletin 33:1245-1255. Garrott, R.A., P.J. White, and J. Rotella. 2009. The Madison headwaters elk herd: Stability in an inherently variable environment. Pp. 191-216 in The Ecology of Large Mammals in Central Yellowstone: Sixteen Years of Inte- grated Field Studies, R.A. Garrott, P.J. White, and F.G.R. Watson,eds. San Diego, CA: Elsavier. Gates, C.C., B. Stelfox, T. Muhly, T. Chowns, and R.J. Hudson. 2005. The Ecology of Bison Movements and Dis- tribution in and Beyond Yellowstone National Park. Calgary, Alberta, Canada: University of Calgary. Geremia, C., P.J. White, R.A. Garrott, R. Wallen, K.E. Aune, J. Treanor, and J.A. Fuller. 2009. Demography of cen- tral Yellowstone bison: Effects of climate, density, and disease. Pp. 255-279 in The Ecology of Large Mam- mals in Central Yellowstone: Sixteen Years of Integrated Field Studies, R.A. Garrott, P.J. White, and F.G.R. Watson, eds. San Diego, CA: Elsevier. Geremia, C., P.J. White, R.L. Wallen, F.G.R. Watson, J.J.J. Treanor, J. Borkowski, C.S. Potter, and R.L. Crabtree. 2011. Predicting bison migration out of Yellowstone National Park using Bayesian models. PLoS One 6(2):e16848. Geremia, C., R. Wallen, and P. J. White. 2014a. Spatial Distribution of Yellowstone Bison-Winter 2015. National Park Service, Yellowstone National Park, Mammoth, WY. September 2014. Available online at http:// www.ibmp.info/Library/OpsPlans/BisonPopulationDiseaseModel_Final_Winter2015.pdf (accessed May 25, 2017). Geremia, C., R. Wallen, and P. J. White. 2014b. Population Dynamics and Adaptive Management of Yellowstone Bison, August 5, 2014. National Park Service, Yellowstone National Park, Mammoth, Wyoming. Available online at http://www.ibmp.info/Library/OpsPlans/2016_BisonRemovalRecommendations_NPS.pdf (accessed May 25, 2017). Prepublication Copy—Subject to Further Editorial Revision 43

Revisiting Brucellosis in the Greater Yellowstone Area Gude, P.H., A.J. Hansen, R. Rasker, and B. Maxwell. 2006. Rates and drivers of rural residential development in the Greater Yellowstone. Landscape and Urban Planning 77:131-151. Gude, P.H., A.J. Hansen, and D.A. Jones. 2007. Biodiversity consequences of alternative future land use scenarios in Greater Yellowstone. Ecological Applications 17:1004-1018. Haggerty, J.H., and W.R. Travis. 2006. Out of administrative control: Absentee owners, resident elk and the shifting nature of wildlife management in southwestern Montana. Geoforum 37:816-830. Hamlin, K.L. and J.A. Cunningham. 2009. Monitoring and Assessment of Wolf-ungulate Interactions and Popula- tion Trends within the Greater Yellowstone Area, Southwestern Montana, and Montana Statewide. Final Re- port. Montana Department of Fish, Wildlife, and Parks, Wildlife Division, Helena, MT. Haroldson, M.A. 2006. Unduplicated females. Pp. 11-16 in Yellowstone Grizzly Bear Investigations: Annual Report of the Interagency Grizzly Bear Study Team, 2005, C.C. Schwartz, M.A. Haroldson, and K. West, eds. Bo- zeman. MT: U.S. Geological Survey. Available online at http://www.arlis.org/docs/vol1/B/4845264/484 5264-2005.pdf (accessed January 4, 2017). Haroldson, M.A. 2007. Unduplicated females. Pp. 8-11 in Yellowstone Grizzly Bear Investigations: Annual Report of the Interagency Grizzly Bear Study Team, 2006, C.C. Schwartz, M.A. Haroldson, and K. West, eds. Bo- zeman, MT: U.S. Geological Survey, Bozeman, Montana, USA. Available online at http://www.arlis.org/ docs/vol1/B/4845264/4845264-2006.pdf (accessed January 4, 2017). Haroldson, M.A. 2008. Assessing trend and estimating population size from count of unduplicated female. Pp. 9-14 in Yellowstone Grizzly Bear Investigations: Annual Report of the Interagency Grizzly Bear Study Team, 2007, C.C. Schwartz, M.A. Haroldson, and K. West, eds. Bozeman, MT: U.S. Geological Survey. Harris, R.B., G.C. White, C.C. Schwartz, M.A. Haroldson. 2007. Population growth of Yellowstone grizzly bears: Uncertainty and future monitoring. Ursus 18:168-178. Hobbs, N.T., G. Wockner, F.J. Singer, G. Wang, L. Zeigenfuss, P. Farnes, and M. Coughenour. 2003. Assessing Management Alternatives for Ungulates in the Greater Teton Ecosystem Using Simulation Modeling. Final Report to U.S. Geological Survey, Fort Collins, by Natural Resource Ecology Laboratory, Colorado State University. Houston, D.B. 1982. The Northern Yellowstone Elk Herd. New York: Macmillan. Jimenez, M.D., and S.A. Becker, eds. 2015. Northern Rocky Mountain Wolf Recovery Program 2014 Interagency Annual Report. U.S. Fish and Wildlife Service, Idaho Department of Fish and Game, Montana Fish, Wildlife & Parks, Wyoming Game and Fish Department, Nez Perce Tribe, National Park Service, Blackfeet Nation, Confederated Salish and Kootenai Tribes, Wind River Tribes, Confederated Colville Tribes, Spokane Tribe of Indians, Washington Department of Fish and Wildlife, Oregon Department of Fish and Wildlife, Utah De- partment of Natural Resources, and USDA Wildlife Services. Helena, MT: USFWS, Ecological Services. Jones, J.D., M.J. Kauffman, K.L. Monteith, B.M. Scurlock, S.E. Albeke, and P.C. Cross. 2014. Supplemental feed- ing alters migration of a temperate ungulate. Ecological Applications 24:1769-1779. Kauffman, M., K. Boroff, D. Peck, B. Scurlock, W. Cook, J. Logan, T. Robinson, and B. Schumaker. 2013. Cost- benefit Analysis of a Reduction in Elk Brucellosis Seroprevalence in the Southern Greater Yellowstone Area. University of Wyoming, Laramie, WY. Kilpatrick, A.M., C.M. Gillin, and P. Daszak. 2009. Wildlife-livestock conflict: The risk of pathogen transmission from bison to cattle outside Yellowstone National Park. Journal of Applied Ecology 46:476-485. Lapp, S., J. Byrne, I. Townshend, and S. Kienzle. 2005. Climate warming impacts on snowpack accumulation in an alpine watershed. International Journal of Climatology 25:521-536. Littell, J.S., M.M. Elsner, G.S. Mauger, E. Lutz, A.F. Hamlet, and E. Salathé. 2011. Regional Climate and Hydrologic Change in the Northern US Rockies and Pacific Northwest: Internally Consistent Projections of Future Climate for Resource Management. Project report: April 17, 2011. Available online at http://cses.washington.edu/ picea/USFS/pub/Littell_etal_2010/Littell_etal._2011_Regional_Climatic_And_Hydrologic_Change_USFS_USF WS_JVA_17Apr11.pdf (accessed January 5, 2017). Lubow, B., and B. Smith. 2004. Population dynamics of the Jackson elk herd. Journal of Wildlife Management 68:810-829. MacNulty, D. 2015. Presentation at the First Committee Meeting on Revisiting Brucellosis in the Greater Yellow- stone Area, July 1-2, 2015, Bozeman, MT. Mao, J.S., M.S. Boyce, D.W. Smith, F.J. Singer, D.J. Vales, J.M. Vore, and E.H. Merrill. 2005. Habitat selection by elk before and after wolf reintroduction in Yellowstone National Park. Journal of Wildlife Management 69:1691-1707. McIntyre, C., and C. Ellis. 2011. Landscape Dynamics in the Greater Yellowstone Area. Natural Resource Tech- nical Report NPS/GRYN/NRTR-2011/506. Fort Collins, CO: National Park Service. 44 Prepublication Copy—Subject to Further Editorial Revision

Geographic Scope of Populations and Disease and Change in Land Use MDFWP (Montana Department of Fish, Wildlife, and Parks). 2004. Montana Statewide Elk Management Plan. Hel- ena, MT: Montana Department of Fish, Wildlife, and Parks. MDFWP. 2016. Montana Statewide Elk Management. Available at http://fwp.mt.gov/fishAndWildlife/management/ elk (accessed April 19, 2016). Meagher, M. 1989. Range expansion by bison of Yellowstone National Park. Journal of Mammalogy 70:670-675. Meagher, M.M. 1993. Winter Recreation-induced Changes in Bison Numbers and Distributions in Yellowstone Na- tional Park. Yellowstone National Park, WY. Middleton, A.D., M.J. Kauffman, D.E. McWhirter, J.G. Cook, R.C. Cook, A.A. Nelson, M.D. Jimenez, and R.W. Klaver. 2013a. Animal migration amid shifting patterns of phenology and predation: Lessons from a Yellow- stone elk herd. Ecology 94:1245-1256. Middleton, A,.D., M.J. Kauffman, D.E. McWhirter, M.D. Jimenez, R.C. Cook, J.G. Cook, S.E. Albeke, H. Sawyer, and P.J. White. 2013b. Linking anti-predator behavior and prey demography reveals limited risk effects of an actively hunting large carnivore. Ecological Letters 16:1023-1030. Middleton, A.D., T.A. Morrison, J.K. Fortin, C.T. Robbins, K.M. Proffitt, P.J. White, D.E. McWhirter, T.M. Koel, D.G. Brimeyer, W.S. Fairbanks, and M.J. Kauffman. 2013c. Grizzly bear predation links the loss of native trout to the demography of migratory elk in Yellowstone. Proceedings of the Royal Society B 280:20130870. Murie, O.J. 1951. The Elk of North America, 1st Ed. Harrisburg, PA: The Stackpole Co. NASS (National Agricultural Statistics Service). 2011. Wyoming Agricultural Statistics 2010. Available online at http://www.nass.usda.gov/Statistics_by_State/Wyoming/Publications/Annual_Statistical_Bulletin/bulletin201 0.pdf. National Geographic. 2016. Special Poster: Yellowstone Elk Migrations, Supervolcano. 229(5). Available online at http://www.nationalgeographic.com/magazine/2016/05/yellowstone-national-parks-elk-migration-map (accessed May 22, 2017). Northern Rockies Adaptation Partnership. 2014. Northern Rockies Adaptation Partnership: Climate Projections. Available online at http://adaptationpartners.org/nrap/docs/NRAP_climate_projections.pdf (accessed January 5, 2017). Olexa, E.M., and P.J.P. Gogan. 2007. Spatial Population structure of Yellowstone bison. Journal of Wildlife Man- agement 71(5):1531-1538. Owen-Smith, R.N., ed. 1983. Management of Large Mammals in African Conservation Areas. Pretoria, South Afri- ca: HAUM Educational. Plumb, G.E., P.J. White, M.B. Coughenour, and R.L. Wallen. 2009. Carrying capacity, migration, and dispersal in Yellowstone bison. Biological Conservation 142:2377-2387. Post, E., and M.C. Forchhammer. 2008. Climate change reduces reproductive success of an Arctic herbivore through trophic mismatch. Philosophical Transactions of the Royal Society B 363:2367-2373. Proffitt, K.M., J.A. Gude, K.L. Hamlin, R.A. Garrott, J.A. Cunningham, and J.L. Grigg. 2010a. Elk distribution and spatial overlap with livestock during the brucellosis transmission risk period. Journal of Applied Ecology 48:471-478. Proffitt, K.M., J.L. Grigg, R.A. Garrott, K.L. Hamlin, J. Cunningham, J.A. Gude, and C. Jourdonnais. 2010b. Changes in elk resource selection and distributions associated with a late-season elk hunt. Journal of Wildlife Management 74:210-218. Proffitt, K.M., N. Anderson, P. Lukacs, M.M. Riordan, J.A. Gude, and J. Shamhart. 2015. Effects of elk density on elk aggregation patterns and exposure to brucellosis. Journal of Wildlife Management 79:373-383. Pulliam, H.R. 1988. Sources, sinks, and population regulation. American Naturalist 132:652-661. Romme, W.H., and M.G. Turner. 2015. Ecological implications of climate change in Yellowstone: Moving into uncharted territory? Yellowstone Science 23:6-13. Schumaker, B.A., D.E. Peck, and M.E. Kauffman. 2012. Brucellosis in the Greater Yellowstone area: Disease man- agement at the wildlife-livestock interface. Human-Wildlife Interactions 6:48-63. Schwartz, C.C., M.A. Haroldson, G.C. White, R.B. Harris, S. Cherry, K.A. Keating, D. Moody, and C. Servheen. 2006. Temporal, spatial, and environmental influences on the demographics of grizzly bears in the Greater Yellowstone Ecosystem. Wildlife Monographs 161:1-68. Schwartz, C.C., M.A. Haroldson, and K. West, eds. 2009. Yellowstone Grizzly Bear Investigations: Annual Report of the Interagency Grizzly Bear Study Team, 2008. Bozeman, MT: U.S. Geological Survey. Singer, F.J., A. Harting, K.K. Symonds, and M.B. Coughenour. 1997. Density dependence, compensation, and envi- ronmental effects on elk calf mortality in Yellowstone National Park. Journal of Wildlife Management 61:12- 25. Prepublication Copy—Subject to Further Editorial Revision 45

Revisiting Brucellosis in the Greater Yellowstone Area Smith, B.L., and S.H. Anderson. 1996. Patterns of neonatal mortality of elk in northwest Wyoming. Canadian Jour- nal of Zoology 74:1229-1237. Smith, B.L., and S.H. Anderson. 1998. Juvenile survival and population regulation of the Jackson elk herd. Journal of Wildlife Management 62:1036-1045. Smith, B.L., and S.H. Anderson. 2001. Does dispersal help regulate the Jackson herd? Wildlife Society Bulletin 29:331-342. Smith, D.W., T.D. Drummer, K.M. Murphy, D.S. Guernsey, and S.B. Evans. 2004a. Winter prey selection and esti- mation of wolf kill rates in Yellowstone National Park, 1995-2000. Journal of Wildlife Management 68:153- 166. Taper, M.L., M. Meagher, and C.L. Jerde. 2000. The Phenology of Space: Spatial Aspects of Bison Density De- pendence in Yellowstone National Park. Bozeman, MT: U.S. Geological Service. Taper, M.L., and P.J.P. Gogan. 2002. The northern Yellowstone elk: Density dependence and climatic conditions. Journal of Wildlife Management 66:106-122. Tercek, M., A. Rodman, and D. Thoma. 2015. Trends in Yellowstone’s snowpack. Yellowstone Science 23:20-27. USDA-APHIS (U.S. Department of Agriculture Animal and Plant Health Inspection Service). 2014. Brucellosis Regionalization Risk Assessment Model: An Epidemiologic Model to Evaluate the Risk of B. abortus Infected Undetected Breeding Cattle Moving out of the Designated Surveillance Areas in Idaho, Montana, and Wyo- ming. Fort Collins, CO: Center for Epidemiology and Animal Health. December 2014. 54 pp. USFS (U.S. Forest Service). 2008. Rocky Mountain Region GIS Data Library - Region Wide Datasets. Available online at https://www.fs.usda.gov/detail/r2/landmanagement/gis/?cid=stelprdb5165938 (accessed May 18, 2017). USFS. 2009. Range Allotment Boundaries for the Northern Region. Available online at https://www.fs.usda.gov/ detailfull/r1/landmanagement/gis/?cid=fsp5_031000&width=full (accessed May 18, 2017). USFS. 2015. Intermountain Region GIS Data Library. Available online at https://www.fs.usda.gov/main/r4/ landmanagement/gis (accessed May 18, 2017). USFWS (U.S. Fish and Wildlife Service). 2016. Draft 2016 Conservation Strategy for the Grizzly Bear in the Great Yellowstone Ecosystem. Available online at https://www.fws.gov/mountain-prairie/es/grizzlyBear.php (accessed January 5, 2017). USFWS/NPS (U.S. Fish and Wildlife Service and National Park Service). 2007. Bison and Elk Management Plan for the National Elk Refuge and Grand Teton National Park. Available online at https://www.fws.gov/ bisonandelkplan (accessed January 5, 2017). Varley, N., and M.S. Boyce. 2006. Adaptive management for reintroductions: updating a wolf recover model for Yellowstone National Park. Ecological Modelling 193:315-339. Vucetich, J.A., D.W. Smith and D.R. Stahler. 2005. Influence of harvest, climate and wolf predation on Yellowstone elk, 1961-2004. Oikos 111:259-270. Wallen, R.L., P.J. White, and C. Geremia. 2015. Historical perspective – from near eradication to livestock to wild- life. Chapter 3 in: P.J. White, R.L. Wallen, and D.E. Hallac. Yellowstone Bison: Conserving an American Icon in Modern Society. Yellowstone Association: Yellowstone National Park. Wang, G., N.T. Hobbs, F.J. Singer, D. S. Ojima, and B.C. Lubow. 2002. Impacts of climate changes on elk popula- tion dynamics in Rocky Mountain National Park, Colorado, U.S.A. Climatic Change 54:205-223. Westerling, A.L., H.G. Hidalgo, D.R. Cayan, and T.W. Swetnam. 2006. Warming and earlier spring increase west- ern U.S. forest wildfire activity. Science 313:940-943. Westerling A.L., M.G. Turner, E.A.H. Smithwick, W.H. Romme, and M.G. Ryan. 2011. Continued warming could transform Greater Yellowstone fire regimes by mid-21st century. Proceedings of the National Academy of Sciences 108(32):13165-13170. WGFC (Wyoming Game and Fish Commission). 2007. Final Wyoming Gray Wolf Management Plan. Available online at https://www.fws.gov/mountain-prairie/species/mammals/wolf/WolfFinal2007WyomingGrayWolfMa nagementPlan.pdf (accessed January 5, 2017). WGFD (Wyoming Game and Fish Department). 2011. Brucellosis Management Action Plan Updates. Available online at https://wgfd.wyo.gov/Wildlife-in-Wyoming/More-Wildlife/Wildlife-Disease/Brucellosis/Brucellosis- Reports (accessed January 5, 2017). WGFD. 2014. 2014 Big Game Job Completion Reports. Available online at https://wgfd.wyo.gov/Hunting/Job- Completion-Reports (accessed May 25, 2017). White, P.J., and R.A. Garrott. 2005a. Northern Yellowstone elk after wolf restoration. Wildlife Society Bulletin 33:942-955. White, P.J., and R.A. Garrott. 2005b. Yellowstone’s ungulates after wolves-expectations, realizations, and predic- tions. Biological Conservation 125:141-152. 46 Prepublication Copy—Subject to Further Editorial Revision

Geographic Scope of Populations and Disease and Change in Land Use White, P.J., R.A. Garrott, and L L. Eberhardt. 2003. Evaluating the consequences of wolf recovery on Northern Yellowstone Elk. National Park Service, Yellowstone Center for Resources, Yellowstone National Park, Wyoming, YCR-NR-2004-02. White, P.J., R.A. Garrott, S. Cherry, F.G.R. Watson, C.N. Gower, M.S. Becker, and E. Meridith. 2009. Changes in elk resource selection and distribution with the reestablishment of wolf predation risk. Pp. 451-476 in The Ecology of Large Mammals in Central Yellowstone: Sixteen Years of Integrated Field Studies, R.A. Garrott, P. J. White, and F.G.R. Watson, eds. San Diego, CA: Elsavier. White, P.J., K.M. Proffitt, and T.O. Lemke. 2012. Changes in elk distribution and group sizes after wolf restoration. American Midland Naturalist 167:174-187. White, P.J., R.A. Garrott, and G.E. Plumb. 2013. Ecological process management. Pp. 3-9 in Yellowstone’s Wildlife in Transition, P.J. White, R.A. Garrott, and G.E. Plumb, eds. Cambridge, MA: Harvard University Press. Wisdom, M.J., and J.G. Cook. 2000. North American elk. Pp. 694-735 in Ecology and Management of Large Mammals in North America, S. Demerais, and P.R. Krausman, eds. Upper Saddle River, NJ: Prentis-Hall, Inc. Wright, G.J., R.O. Peterson, D.W. Smith, and T.O. Lemke. 2006. Selection of northern Yellowstone elk by gray wolves and hunters. Journal of Wildlife Management 70:1070-1078. Prepublication Copy—Subject to Further Editorial Revision 47

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Brucellosis is a nationally and internationally regulated disease of livestock with significant consequences for animal health, public health, and international trade. In cattle, the primary cause of brucellosis is Brucella abortus, a zoonotic bacterial pathogen that also affects wildlife, including bison and elk. As a result of the Brucellosis Eradication Program that began in 1934, most of the country is now free of bovine brucellosis. The Greater Yellowstone Area (GYA), where brucellosis is endemic in bison and elk, is the last known B. abortus reservoir in the United States. The GYA is home to more than 5,500 bison that are the genetic descendants of the original free-ranging bison herds that survived in the early 1900s, and home to more than 125,000 elk whose habitats are managed through interagency efforts, including the National Elk Refuge and 22 supplemental winter feedgrounds maintained in Wyoming.

In 1998 the National Research Council (NRC) issued a report, Brucellosis in the Greater Yellowstone Area, that reviewed the scientific knowledge regarding B. abortus transmission among wildlife—particularly bison and elk—and cattle in the GYA. Since the release of the 1998 report, brucellosis has re-emerged in domestic cattle and bison herds in that area. Given the scientific and technological advances in two decades since that first report, Revisiting Brucellosis in the Greater Yellowstone Area explores the factors associated with the increased transmission of brucellosis from wildlife to livestock, the recent apparent expansion of brucellosis in non-feedground elk, and the desire to have science inform the course of any future actions in addressing brucellosis in the GYA.

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