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OCR for page 32
7
Evaluation of Final Reports
of Individual Studies
INTRODUCTION
THE STRUCTURE OF THE ecological monitoring program was segmented,
rather than integrated, in that the research teams worked independently of each
other. The purpose of ]:TTRI's solicitation in March 1982 was to attract sub-
contracting researchers to develop and conduct separate ecological monitoring
studies that would determine whether low-level, long-term electric and mag-
netic fields (EMFs) and gradients produced by the ELF communications sys-
tem would affect vegetation or wildlife in and near the system area or other-
wise result in changes in individual organisms or their communities. Eventu-
ally physiologic, developmental, behavioral, and ecological aspects of predom-
inant organisms in upland, riverine, and wetland habitats near the Navy's ELF
transmitting facilities were monitored for possible effects of EMFs produced
by the Navy's antennas. The organisms and ecological relationships selected
for monitoring were chosen because they were judged to be important to their
ecosystems and to be of interest to local residents (Zapotosky and Gauger
1993~.
The monitoring program studies were designed to compare data collected
at control sites with data collected at treatment sites. As discussed in Chapter
2, the paired sites were intended to have matched environmental factors but
to be dissimilar in the magnitude of their exposure to the 76-Hz EMFs gener
32
OCR for page 33
EVALUATION OF FINAL REPORTS
33
ated by the communications system antennas. Sites exposed to those 76-Hz
EMFs were established by locating treatment sites near or within the rights-of-
way for the antennas; control sites had to be far enough from the communica-
tions system that EMF intensities resulting from antennas would be substan-
tially lower than those at treatment sites. However, control sites had to be
close enough to have environmental factors similar to those of their matched
treatment sites. Siting criteria called for intensities of the 76-Hz EMFs at
treatment sites to be at least 10 times those at control sites, for intensities of
the 76-Hz EMFs at treatment sites to be at least 10 times those of the 60-Hz
EMFs at treatment sites and control sites, and for intensities of the 60-Hz
EMFs at treatment sites to be within 10 times those at control sites (Haradem
et al. 19941.
This chapter presents evaluations of the ~ ~ final ecological reports on the
following topics: wetlands, slime mold, Wisconsin birds, Michigan birds,
small vertebrates, litter decomposition and microflora, upland flora, aquatic
ecosystems, pollinating insects, soil arthropods and earthworms, and soil
amebas. The committee combined its discussion of Wisconsin and Michigan
birds in this chapter. The committee used the following criteria to evaluate
the reports: adherence to the original project proposal, adequacy of selection
of species and response variables, adequacy of experiment design and imple-
mentation (including biologic and ecological sampling techniques, physical
measurements, and statistical power), responsiveness to reviewers' comments
while studies were being conducted, presentation of results (including consid-
eration of alternative analyses or hypotheses and interpretation), and appropri-
ateness of conclusions (including validity and uncertainties). The committee
found that the various criteria did not warrant the same amount of discussion
for each study.
WETLANDS
PROJECT PROPOSAE
The authors of the wetlands final report (Guntenspergen et al. 1989)
pointed out that wetlands in the upper Midwest are sensitive ecosystems and
are common near the ELF communications system sites, especially the Wis-
consin location. They pointed out that past studies on effects of ELF EMFs
indicated that plant membranes might be affected by electromagnetic radiation.
OCR for page 34
34 EVALUATION OF ELF ECOLOGICAL MONITORING PROGRAM
Therefore, they proposed to look for changes in plant competitive ability
through measurement of plant or ecosystem functions that were related to
membrane functions. Possible changes included leaf diffusion resistance, foliar
nutrient content, changes in functions related to transport of water and nutri-
ents across membranes, and decomposition by microorganisms, all of which
depend heavily on secretion and adsorption through membranes. The basic null
hypothesis of the wetland-monitoring project was that ELF EMFs resulting
from the operation of the Navy antenna have no effect on selected ecosystem
variables.
SYSTEM, SITE, AND SPECIES SELECTION
Much of the initial, pilot-study year of this project was spent in establish-
ing study sites and testing methods. Stearns et al (1982) described five north-
ern wetland vegetation types in Wisconsin: northern conifer swamp, shrub
wetland, emergent marsh, northern sedge meadow, and open bog. Because
the northern conifer swamp was common near the ELF location in Wisconsin
and offered all life forms-including trees, shrubs, herbs and nonvascular
plants it was chosen as the ecosystem type for monitoring.
The authors of the proposal recognized the heterogeneity of the region
near the ELF antenna, as well as the heterogeneity among stands of the same
type of wetland. That created a problem in site selection but was addressed
through identification of sites with close similarities in vegetational composi-
tion and environmental characteristics. The former was determined through
use of contingency tables and similarity indexes (such as Sorensen's Index),
and the latter through measurement of soil-water temperature and pH, cation
concentrations, and redox potential. in general, it was thought that sites with
similar vegetation would have similar, but certainly not identical, environ-
ments. More than 200 potential sites were selected from aerial photographs;
these were reduced to SO sites for priority-setting, and then 15 sites were
selected for measurement of 60- and 76-Hz EMFs in potential study plots, one
per site. Eleven sites were eventually chosen for initial summer (1983) stud-
~es.
Location of "similar" sites was based on relative EMF intensity.
Electric-field strength measured by lITR] was used to establish intensity gradi-
ents; these were called background, intermediate, antenna, and ground to
correspond to location of sites relative to ELF facilities. No true control could
be established, because the ELF communications system was already function
OCR for page 35
EVALUATION OF FINAL REPORTS
35
ing, so the background sites were considered as control sites. In most cases,
three sites were used for each exposure scenario, but only two ground sites
were used within one large peatiand. Although the selection of study sites
satisfied the criteria established by IITR} and a gradient of exposure from
treatment sites to control sites existed, the three treatment sites varied among
themselves in terms of EMF intensity. For example, 1987 field measurements
showed that the plots within the antenna treatment sites ranged from 0.053 to
0.196 V/m in electric-field intensity and from 6.! to 19.S mG in magnetic-
f~eld intensity.
Selection of the northern conifer forest wetland allowed use of tree,
shrub, and herb species, when appropriate, for determination of response
variables associated with plants. Final experimental species were not selected
until 1985. Labrador tea (Ledum groeniandicum) was selected as the primary
species for measuring stomata! resistance after other species were tried; for
instance, the leaf anatomy of black spruce (Picea mariana) made stomata!
measurement difficult. Labrador tea is a common shrub throughout the conifer
wetlands of Wisconsin. Labrador tea leaves replaced pure cellulose sheets in
the decomposition studies for testing of "natural plant materials" and to im-
prove within-site measurement consistency. Black spruce, Labrador tea, the
shrub leather leaf (Chamaedaphne calyculata), and the herb false solomon's
seal (Smilacina trifolia) were used for foliar nutrient content; this permitted
comparisons across life forms. Nitrogen fixation studies, initially on alder and
then on moss and peat, were dropped during the study period.
RESPONSE VARIABLES
Response variables chosen for the wetland studies and used throughout
the study period all were related to membrane-associated functions. The choice
was based on a National Research Council (NRC 1977) report and other stud-
ies on effects of EMFs that indicated that biologic and ecological responses to
EMFs were most likely in functions associated with membranes. Stomatal
resistance was chosen as a response variable because it is associated with water
transport across membranes and all vascular plants could potentially be influ-
enced through this leaf function. Nutrient content of leaves was examined
because it is closely related to nutrient transport across membranes in root
cells. Decomposition was examined because it is associated with across-mem-
brane secretion of enzymes by microorganisms and adsorption of decomposed
cellulose and other organic compounds. Other processes could have been
OCR for page 36
36 EVALUATION OF ELF ECOLOGICAL MONITORING PROGRAM
examined, such as growth rates or species composition changes, but they were
not, because they were considered likely to result in too much variability
within sites and were considered to be long-term response variables. Nitrogen
fixation was examined for a couple of years, but that effort was eventually
dropped from the program because the method was not reliable.
EXPERIMENT DESIGN
The wetland monitoring study was conducted from 1983 through 1987.
The first year was used for selecting sites, developing and evaluating protocol,
and beginning preliminary sampling. After experimentation with a rectangular
plot design in the first year in which all the experimental measurements were
made in a regular array throughout the plot, the study team settled on a 70 x
15-m rectangular plot for all experiments, oriented with the long axis parallel
to the closest antenna. Six square subplots were designated in the rectangular
plot with centers (where shallow groundwater wells were placed) 10 m apart.
All measurements of response variables were taken within these subplots; all
selected species were within each subplot.
Environmental data were collected monthly from May to September (the
frostfree period). ELF EMFs were measured once a year and assumed to be
constant over the year. The antennas were capable of operating at full strength
from 1985 through 1987, when most of the established protocols were in
place; however, the antennas were not on full-time during this period, and it
is not certain to what extent the off periods were taken into account in the
study. That might be important for response variables that respond instanta-
neously or in a short term.
Biologic Sampling
The final report presented three biologic measurements used to determine
possible effects of ELF EMFs on wetland ecosystems in the vicinity of the
Wisconsin transmitter facility (Guntenspergen et al. 1989~: stomata! resistance,
foliar nutrients, and decomposition.
Stomatal Resistance The primary results of stoma/al-resistance tests were
based on responses of Labrador tea, a common species in every study bog.
Other species were tested both because of ease of measurement and because
OCR for page 37
EVALUATION OF FINAL REPORTS
37
of response to different light levels. Spruce and smilacina were dropped be-
cause of measurement difficulties. The equipment used for measurement of
stomata! resistance was a null-balance diffusive-resistance porometer, which
measures the rate of water-vapor diffusion through the stomata. It is standard
equipment for such measurement, and the method is easily replicated if need-
ed.
Stomatal resistance was measured in leather leaf and Labrador tea under
different light intensities. Labrador tea, least responsive to differences in light
especially at low intensities, was selected as the species for testing the re-
sponse of plant stomata! resistance to ELF EMFs. That choice essentially
eliminated light as one of the independent environmental variables that might
have to be considered a covariate in later statistical analyses. Selection of only
one species, however, implied the assumption that all other species would
respond to ELF EMFs in a similar fashion. if different species had different
stoma/al-resistance responses to light levels, might this indicate different re-
sponses to other external variables? That is partially addressed by the results,
which include data on leather leaf, which was dropped as a consequence of
tests on light intensities.
Measurements were made during four periods at all I! study sites in
August and September 1986 and 1987. Measurements were made over several
days in each sample period, and there was an attempt to stratify measurements
to cover all environmental variables, especially light intensity and cloud cover,
for the background, intermediate, antenna, and ground sites. The number of
samples taken was doubled between 1986 and 1987 to allow for resolving 20%
differences in means at p = 0.05 with an 80% probability. The increase in
samples increased variability in the measurements of external environmental
conditions. That situation is commonly found in field sampling. An increase
in sampling frequency might reduce the statistical significance of the results
because it increases variability in sample measurements.
Foliar Nutrients Changes in foliar nutrient concentrations in plants grow-
ing in a relatively nutrient-poor environment were considered a possible indi-
cator of the condition of various plant biochemical pathways. The initial spe-
cies for foliar-nutrient sampling were a shrub (leather leaf), an herb (smilaci-
na), two sedges, and a tree (black spruce). Labrador tea was substituted for
the sedges because destructive harvesting of these sedge species might have
damaged their limited populations. Sampling periods were based on phenol-
ogy; thus, herbs were sampled earlier in the season than shrubs. Sample size
was increased several times over the early years of the study to improve the
OCR for page 38
38 EVALUATION OF ELF ECOLOGICAL MONITORING PROGRAM
power of the statistical analysis, eventually reaching 396 (6 x 6 x ~ i) sam-
ples per species per sample date. Only current-year foliar tissue was collected.
Standard methods were used for preparation and analysis for calcium, magne-
sium, and potassium. Samples from 1987 were also analyzed for manganese
and phosphorus. For quality control, National Bureau of Standards (NBS)
standards were analyzed with field samples, and spikes of known-cation stan-
dard solutions were added to field and NBS samples.
Decomposition Two approaches were used for decomposition studies.
The first used pure cellulose as a substrate, and the second used Labrador tea
leaves. The use of pure cellulose was intended to provide a uniform substrate
for decomposition. If preweighed samples of cellulose were placed in a f~ber-
glass bag and inserted vertically into the peat, less variation was expected
among all samples. However, the cellulose became soft, adhered to the bag,
and could not be retrieved fully for posttreatment weighing. Labrador tea
leaves were used instead of cellulose. Bags with about the same amount of
leaf material were mixed and randomly selected for placement in the bogs.
The use of Labrador tea leaves resulted in less within-group variance.
The decomposition bags were allowed several months for incubation in
situ. The bags were retrieved, and the cellulose or leaf samples were removed,
cleaned of foreign material, dried, and weighed. Weight loss indicated decom-
position. The duration of incubation varied from 4 to 12 months.
Environmental Characteristics
The primary environmental characteristics measured during the study,
excluding ELF-EMF exposure levels, were those of the interstitial water with-
in each wetland site. The characteristics of the bog water were considered to
influence decomposition rates and root activity. Shallow groundwater wells
were placed in the center of each of the six subplots in the study plot at each
site. Water-quality measures were depth to water table, depth to anaerobic
zone, reduction-oxidation potential, specific conductance, temperature, pH,
and calcium, magnesium, and potassium contents. Dissolved organic carbon
was measured in 1984 only. Water samples were prepared with standard
methods.
No data in the wetlands report indicate regular measurement of ambient
temperature, rainfall, or other external climatologic conditions. Measurements
OCR for page 39
EVALUATION OF FINAL REPORTS
39
of water quality, light intensity and leaf temperature made during various
sampling periods appear to have been considered sufficient for evaluating the
influence of the external conditions.
Statistical Methods
Statistical methods were chosen to test the null hypothesis that ELF
EMFs resulting from the operation of the Navy antenna have no effect on
selected ecosystem variables. Researchers primarily used nested analysis-of-
variance (ANOVA) models to examine treatment and control groups.
Stepwise-multiple-regression models were used to explain the variance in the
dependent biologic variables (stomata! resistance, foliar nutrients, and decom-
position rates) on the basis of environmental variables (such as water-quality
data) and ELF-EMF data. Significance levels (p=0.05) of the two models
were compared. In a few instances, the models did not agree, and lack of
significance within one mode! was selected as the appropriate test of the re-
sponse variable (i.e., it was not significantly influenced by ELF EMFs).
Reviewers of the project over the period of the study sometimes questioned the
use of stepwise multiple regression because of the interdependence of the
variables, even those considered independent. In ANOVA, the variables were
usually considered covariates; in multiple regression, they were treated as
independent. Treating variables in this manner is a common practice in eco-
logical studies, the understanding being that no variables in an ecosystem are
truly independent. The use of stepwise regression attempts to alleviate this
concern.
To show the relationship of environmental variables to decomposition
rates, all environmental data collected during the incubation period were sub-
jected to principal-components analysis (PCA), an approach that reduces the
number of independent variables to a few "composite" variables. The princi-
pal components representing environmental data were then regressed (in step-
wise fashion) against decomposition rates.
Several times during the study period, the number of samples was in-
creased to increase the power of the statistical analysis. That was done mostly
for the foliar nutrient analysis. Other levels of sampling were considered
sufficient, after preliminary studies, to achieve the established level of confi-
dence at a 0.05 significance level.
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40 EVALUATION OF ELF ECOLOGICAL MONITORING PROGRAM
Quality Assurance and Quality Control
Quality assurance and quality control, especially as related to chemical
analysis, were addressed in the methodology discussion of the final report.
Methods selected for stomata! resistance were standard and repeatable.
Decomposition-rate methods were straightforward. The research design estab-
lished for this study helped to avoid pseudoreplication and allowed sound
ANOVA of data from study sites.
Exposure Assessment
UTR} provided ELF-EMF exposure data at the background, intermediate,
antenna, and ground sites. ITTR] measured ELF EMFs annually at each sam-
ple plot at the study locations. The 1987 annual report (Guntenspergen et al.
1988) made it obvious that the investigators took into account the spatial EMF
gradient resulting from antenna operation and used it in regression analyses.
The ELF communications system was not operated continuously; study
sites were therefore not consistently exposed to ELF EMFs. Different por-
tions of the antennas were turned on and off several times each day, with
varying modulations, frequencies, current intensities, and phase angles. The
Navy provided ITTR} and researchers with detailed logs of antenna activity.
The final wetlands report does not indicate whether the antennas were on or
off during field measurements or whether information on the antenna operation
was used in data analyses.
Response variables would likely have varied in their sensitivity to antenna
operations. For example, annual decomposition rates could be related to the
annual EMF measurements, but stomata! resistance might have an immediate
cellular response to external factors, such as light, temperature, and ELF
EMFs. Use of short-term response variables, such as stomata! resistance,
could have created analytic difficulties. Field measurements of these very
short-term response variables would have had to be timed in coordination with
antenna operations to ensure measurement of possible EMF influences that
might not be observable when the antenna is off.
In 1987, stomata! resistance was measured in August, the same month
that I]:TRI measured exposure levels at each study plot. There is some evi-
dence in the 1987 annual report (p. 17) that the researchers examined the on-
off status of the Wisconsin transmitting facility relative to their field sampling.
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EVALUATION OF FINAL REPORTS
41
If these measurements occurred at the same time, the exposure assessment of
this study took into account the need to measure short-term responses while
the antenna was actually on. The final report does not address the coordination
of field measurements with antenna activity. If the measurements were not
coordinated, the use of a short-term response variable, such as stomata! resis-
tance, is questionable.
RESPONSE TO REVIEW
The researchers received comments from reviewers starting with the 1983
annual report (Stearns et al. 1984~. Common comments were related to site
characterization, use of specific response variables and timing of measure-
ments, and level of sampling for adequate statistical analysis. The study design
was modified to accommodate some of the critics' comments; others were
addressed through explanations of why changes were not made.
For example, a criticism of site selection was lack of extensive soil data.
The researchers characterized similar sites as those with similar peat sub-
strates, but then emphasized measurement of interstitial water at each site as
more appropriate for studying substrate composition.
The use of stomata! conductance as a response variable was acceptable
to the reviewers, but they were concerned that because this variable is so
closely influenced by light and temperature, it needed to be measured at the
same time of day under similar conditions of light and temperature to yield
useful comparisons. The researchers selected the species with the least re-
sponse to light variation because it was impossible to make all measurements
at the same time of day or even on the same day.
The use of foliar composition was questioned because it is not considered
appropriate for determining soil nutrient availability in agricultural systems.
The researchers pointed out, however, that foliar composition is commonly
used in natural ecosystems as an indicator of plant condition and therefore was
appropriate for this study. Although the final statistical approaches did not
fulfill all the requirements of the reviewers, the study design was altered in
some cases to increase sample size. Inappropriate uses of statistical terms,
pointed out by reviewers, also were corrected in the final report.
In most cases, the investigators did respond to reviewers' comments, thus
producing an improved final document.
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42 EVALUATION OF ELF ECOLOGICAL MONITORING PROGRAM
PRESENTATION OF RESULTS
Alternative Hypotheses
Results were presented in different forms: graphical presentations with
bar graphs (often showing standard errors), tables with nested ANOVA analy-
ses, and tables with stepwise-multiple-regression analyses. The initial proposal
suggested that ANOVA would be the appropriate statistical approach to test
the null hypothesis of no difference between or within treatment and control
sites. Development of data sets also demonstrated to the researchers that there
was a need to attempt to explain the variances of the biologic responses be-
tween and within treatments, in addition to assessing them. Although no alter-
native hypotheses were presented, use of stepwise multiple regression to assess
the significance of independent environmental variables indicates possible
consideration of an additional hypothesis that variances in dependent biologic
responses are explained no more by natural external environmental factors than
by ELF EMFs.
Interpretation
Interpretation of results was based primarily on comparison of the two
statistical approaches to the empirical data. If the ANOVA models indicated
that there was no greater difference between study sites than within study sites
at the 0.05 significance level, the researchers interpreted that as conclusive.
They checked their interpretation by applying the multiple-regression models
that used environmental characteristics (sometimes considering biologic vari-
ables as independent, such as leaf nutrients for stoma/al-resistance compari-
sons) and ELF-EMF characteristics (in most cases in a PCA form). In many
cases, neither environmental nor ELF-EMF principal components accounted
for much of the variance of the response variable. in a few cases, a signifi-
cant correlation for a response variable was found using the regression mode!
that was not found using the ANOVA model. The researchers interpreted the
mode! showing no significant correlation to be correct. That raises the question
of the level of confidence selected to demonstrate statistical significance of the
ANOVA and multiple-regression models. For this study, a significance level
of 0.05 was chosen. Considering the variability of the ecosystems being stud-
ied, this is probably appropriate, although many statisticians might consider
it no more than an indication that the variance of the results depends on
chance.
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~ 00 EVALUATION OF ELF ECOLOGICAL MONITORING PROGRAM
only the first three foraging trips were measured. Observer identity was used
as a variable in the ANOVA mode! to test for bias. Because sex ratios can
vary with nest diameters and depths, data not standardized for these variables
were excluded from the analysis.
Exposure Assessment
L
Measurements of actual ELF-EMF exposures are reported for the treat-
ment and control sites, with maximums and minimums given for one of the
two treatment sites for June through August. The 76-Hz magnetic-flux densi-
ties at the treatment site were 330 times stronger than at the control site.
Exposure varied substantially between treatment sites, within treatment
sites, and among years. The two treatment sites differed, in cumulative gauss-
hours, by a factor of 2 (Strickler and Scriber 1994, Fig. 13~. Nest hutches
differed within a treatment site by up to a factor of 100. Pretreatment years
included low to 50% power (1983-19881. Mobile adult bees are subject to
different exposures, but developing progeny are stationary and should have a
consistent exposure, although this obviously varied between nests, sites, and
years.
The researchers argue that this variation in ELF EMFs is unlikely to be
Important because the bees will show a threshold response to the large expo-
sure differences between treatment and control sites. However, if the re-
sponses are dose-dependent, this variation could confound the results. If there
is a humped response curve (maximum at some intermediate level), ELF-EMF
effects would be missed in the analysis.
RESPONSE TO REVIEW
Reviewers' suggestions to focus the initial study were heeded and con-
tributed greatly to the success of this research. Other suggestions about meth-
ods, such as shielding overwintering progeny from electric fields indoors and
including observer bias as a variable, were also followed.
Two major suggestions were not followed, for reasons that are not en-
tirely clear. One was to use a BACT analysis with covariates. The other was
to increase replication by placing fewer trap nests at many sites. The original
design had four sites (with no replicates), but two of these were dropped.
Given that ELF EMFs become ambient at 1.6 km, one reviewer suggested that
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EVALUATION OFFINALREPORTS
lO]
control and treatment sites could be closer than 48 km apart, which could
reduce some of the other environmental differences between sites. increased
replicates and reduced variation could have allowed for stronger conclusions
about the results.
PRESENTATION OF RESULTS
The authors are forthright about problems, such as unreliable data, which
were eliminated from the analysis, and other confounding variables. A
strength of this report is the clarity of discussion about problems and alterna-
tives.
Alternative hypotheses were often used to dismiss results that indicated
potential ELF-EMF effects. The researchers' arguments are reasonable and
soundly based on the data, but opposing arguments could be made for real
ELF-EMF effects in most cases. Of eight parameters analyzed for one or both
species, five showed statistically significant ELF-EMF effects for one or the
other species, but only one, overwintering mortality, is interpreted as a possi-
ble real ELF-EMF effect and this effect is regarded as ambiguous.
Statistically significant effects on three parameters (cell length, leaf num-
ber, and nest orientation) are interpreted as being caused by factors other than
ELF EMFS. Cell lengths became more similar after full antenna operation for
one species. The authors argue that ELF EMFS were not likely to have pre-
vented the reduction in cell length (0.2 mm of ~ ~ . ~ mm) at the treatment site.
Leaf number also became more similar after the antenna began operating at
full power for one species; that is the opposite of what is expected if ELF
EMFS are detrimental. The authors also argue that this difference (0.5 leaf/
cell) is trivial and unlikely to affect fitness or population growth. Nest orien-
tation was argued as reflecting differences in local flower availability or shad-
ing, rather than ELF-EMF exposure.
Effects on nest thickness were not statistically significant, but the authors
neted that the effect would have had to be very large to be detected with their
test (hence, they dismissed this as a strong conclusion). They also cautioned
against accepting the null hypothesis for trip duration and sex ratios, because
of low power; that is commendable. In contrast, they accept the null hypothe-
sis of no effects on offspring weight because statistical power was good.
The ELF-EMF effect on overwintering mortality was statistically signifi-
cant for one species. Mortality was lower at the treatment site at low antenna
power but increased to the level of the control site after full antenna operation.
OCR for page 102
~ 02 EVALUATION OF ELF ECOLOGICAL MONITORING PROGRAM
The authors dismiss this as an ELF-EMF effect because mortality became
increasingly similar and because of protocol changes, parasitism, and small
sample sizes. However, mortality did increase after full antenna operation.
Overwintering mortality was also found to differ significantly with ELF-
EMF exposure in a nest-transplant experiment. Nests occupied at a treatment
site but moved and overwintered at control site showed lower mortality than
nests occupied and overwintered at the treatment site. In addition, the mortal-
ity of transplanted nests was similar to that of the nests occupied and left at the
control site. Although that is strong evidence for ELF-EMF effects, the au-
thors argue that the effect is unlikely to be caused by ELF-EMF exposure.
The sources of mortality were not emphasized in the researchers' report,
because the sources were difficult to determine. For example, the researchers
could not separate prepupal mortality in winter from that in summer, fall, or
spring. They speculate that weather probably was important for much of the
prepupal mortality. Because prepupal mortality varied greatly between years
and sites, they decided to test the potential effects of ELF-EMFs on mortality
after a bee had survived to the prepupal stage. That would reduce the varia-
tion caused by site and weather differences. For this study, a major parasite
was the cuckoo bee, Coelioxys, which is also a megachilid and could not be
distinguished from the host in the prepupal stage. Therefore, both parasites
and hosts are included in the mortality data. They argue that hosts and para-
sites would probably have been similarly affected by ELF EMFs so this should
not distort the results or interpretations.
Overall, the authors conclude that ELF-EMF impacts are absent or at
most minimal.
CONCLUSIONS
Validity
Two major problems in the design seriously reduce the ability to detect
statistically significant ELF-EMF effects: low replication (pseudoreplication)
and confounding variables. The treatment and control sites initially differed
in many factors, including flower resources, which also probably varied inde-
pendently over time.
Otherwise, the details of the study were well designed and well executed.
Great care was taken in standardizing variables and in maintaining data qual-
ity. A more appropriate statistical analysis could have been used, but it is
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EVALUATION OF FINAL REPORTS
103
doubtful that different conclusions would be reached. Problems are discussed
at length.
Uncertainties
The authors' conclusion that ELF-EMF effects are absent or minimal is
uncertain because of the weak ability to detect effects. That results in a great-
er likelihood of accepting a false null hypothesis (type II error) than of reject-
ing a true null hypothesis (type T error or false positive). A type Il error
would also be likely if the response curves were dose-dependent and either
monotonic or hump-shaped. Therefore, the fact that the authors did find
statistically significant effects requires careful consideration. The finding of
increased overwintering mortality in two independent experiments makes an
especially strong case for the existence of statistically significant ELF-EMF
effects.
The researchers' conclusion that ELF-EMF effects are absent or minimal
might reflect the low power of the tests rather than the reality of no effects.
Real effects would likely have been difficult to detect because of the small
sample sizes and high variation in many factors. Therefore, the conclusion of
"no effects" might, in fact, be based on the acceptance of a false null hypothe-
sis (type TT error). A type lI error would also be likely if the response were
dose~ependent and showed a monotonic or hump-shaped relationship to dose.
To their credit, they discuss their reasons at length, but good reasons
could be advanced for rejecting the null hypothesis in most cases. They also
argue that the few statistically significant effects are small and would have
little impact on populations. That is an erroneous argument because small
differences over a long time can produce large changes in population sizes.
Summary
The authors' final conclusion that ELF-EMF effects are absent or mini-
mal is questionable. The authors' explanations are inadequate for discounting
potential ELF-EMF effects and for accepting the null hypothesis of no effect.
Given the weak ability of the experiment design to detect ELF-EMF effects,
any significant effects should be given careful consideration. Similar argu-
ments were made by one reviewer of the final report who strongly feels that
ELF-EMF effects were clearly demonstrated in this study. More independent
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1 04 EVALUATION OF ELF ECOLOGICAL MONITORING PROGRAM
replicates would help to determine whether the statistically significant effects
are caused by ELF EMFs or by some other factor.
SOIL ARTHROPODS AND EARTHWORMS
PROJECT PROPOSAL
Soil macrofauna, such as arthropods and earthworms, control many of
the decomposition processes critical to ecosystem function. It makes sense to
examine the abundances, activity, and demographics of dominant soil animals.
This study has six parts: soil and litter arthropod censuses, analyses of
surface-active arthropod activity via pitfall traps, analyses of earthworm popu-
lations sampled by square cores, analyses of growth and reproduction rates of
earthworms incubated in soil bags, analyses of litter inputs sampled by litter
traps, and analyses of litter-decomposition rates measured in litterbags.
SPECIES AND SYSTEM SELECTION
Soil and Litter Arthropods
The species chosen for analysis were essentially the numerically dominant
mites and collembolans (springtails) found in soil cores and litter samples.
With no reason to choose a particular species, it is sensible to use the domi-
nant species, because their frequency of occurrence makes them conducive to
statistical analysis, compared with organisms that occur in only a few samples.
Surface-Active Arthropods
The researchers selected species on the basis of their abundance and
commonness, which is reasonable. it would also have been desirable to pick
species on the basis of relative uniformity in distribution over the areas of
interest, so as to diminish the statistical problems of place-to-place and time-
to-time variations. in addition, arthropods that actively forage on the soil
surface could exhibit sublethal effects because of environmental perturbations
(through altered behavior), and their activity patterns are potentially good
indicators of ELF-EMF effects.
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EVALUATION OF FINAL REPORTS
Earthworm Field Populations
105
The researchers examined all nine earthworm species found at the treat-
ment or control sites. Because they looked at all species, there was nothing
arbitrary in the analysis, and the thoroughness is commendable.
Earthworm Growth and
Reproduction in Incubation Bags
In addition to counting animals, it is a good idea to look for per capita
differences in reproductive rates or growth. Using such demographic charac-
teristics can yield far more sensitive indicators of ELF-EMF effects than
waiting for population densities to reflect differences due to the activation of
the antenna.
Litter Inputs
One can imagine ELF-EMFs influencing tree phenology, leaf production,
and leaf abscission in a way that could alter litter inputs into forest soils. The
measurement of litter inputs represents a sound research decision.
Litter Decomposition
Litter decay is certainly an appropriate system process to examine, espe-
cially in the context of concordant measures of earthworm and other macro-
fauna associated with decomposition.
SEEECTION OF RESPONSE VARIABEES
Most of the response variables involved counts or densities of individuals
by species, an unassailable focus for analysis. Measures of community struc-
ture, such as diversity and evenness indexes, were also examined; these aggre-
gate indexes are difficult to interpret, and any changes in them would be
impossible to understand without also analyzing effects species by species.
However, these community indexes play a minor role in the analyses and are
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distracting only in that they add length to an already confusingly long docu-
ment.
A few response variables deserve comment. For the earthworm compo-
nent, the vertical distribution of worms was examined as a possible indicator
of changes in behavior or habits. The age distribution of worms and the size
and cocoon production of earthworms were examined as functions of year
(preoperational versus operational antenna years). in the earthwo~n~-incuba-
tion experiments, the growth and reproductive status of "enclosed" earthworms
were followed as a function of antenna operation and previous exposure.
Because earthworms can live several years and might require 3 or more years
to reach maturity, the attention to growth and reproductive rates in the earth-
worm component of the study is commendable; these demographic rates
should be more sensitive than absolute population numbers (which could re-
flect long time lags and history). Leaf litter inputs were assessed by lumping
grams of dry weight per square meter for basswood, maple, and all other
species. Litter decomposition was assessed on the basis of the percentage of
initial mass remaining. Mass loss is a crude measure of decomposition, and
it would have been far better if a more-direct measurement of nutrient release
had been obtained.
EXPERIMENT DESIGN
Biologic and Ecological Sampling Techniques
The field design involved a single control site and a single treatment site
for all components of the research. Replication is therefore impossible, and
the only appropriate statistical analysis uses a before-and-after, control-and-
impact (BACT) approach. Although the absence of replication might be un-
avoidable, some aspects of the rationale are dubious. First, the two sites were
not comparable: they had strikingly different earthworm and arthropod fauna.
Second, for the earthworm-incubation experiments, the experiment design
involved moving earthworms to a control site at which they did not occur
naturally in any abundance (compared with either the treatment site or the sites
from which they were taken). Thus, the experiment could be interpreted as
an investigation of the effects on a species' growth and reproduction of trans-
planting it out of its habitat. The detailed studies of earthworm size, age, and
reproductive structure were confined to species that occurred only at the treat-
ment site. That makes it virtually impossible to distinguish possible effects of
antenna activation from effects of other temporally varying factors.
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EVALUATION OF FINAL REPORTS
Physical and Chemical Measurements
107
ELF EMFs were measured, and it was well demonstrated that the treat-
ment site exhibited ELF-EMF levels at least 10 times those at the control site.
The sites fulfilled TTTRI's other criteria as well.
Statistical Methods
The studies had four severe statistical flaws. First, when the BAC!
analysis was used, the appropriateness of its assumptions of no serial
autocorrelation and of additivity was never evaluated. Because the control and
treatment sites clearly differed before the antenna was turned on, this is a
serious problem. Second, often a simple ANCOVA was applied, although a
repeated-measures approach is more appropriate. Third, the power of the tests
and sampling scheme was low. For example, to sample surface-active arthro-
pods, only 10 pitfall traps were used per site, an absurdly low number. In
addition, given the large differences between sites and the variability in data,
one questions how powerful the BAC! could be in detecting ELF-EMF effects.
Fourth, for many of the earthworm analyses, the only data came from the test
site, and no serious effort was made statistically to distinguish temporal varia-
tion due to antenna activation from temporal variation due to other environ-
mental variables.
PRESENTATION OF RESULTS
Consideration of Alternative Analyses
In general, analyses did not include much consideration of alternative
approaches. For example, numerous BACI tests were performed, some of
which indicated statistically significant effects. No serious effort was made to
determine whether those effects were due to ELF EMFs or to some other
environmental characteristics associated with the difference between control
and treatment sites.
Interpretation
The interpretations of data seem predisposed to conclude that ELF-EMF
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exposure had no statistically significant effect; several potentially significant
results (as detected via BACI) were consistently dismissed. Biologically, that
might be the correct conclusion, but the interpretation gave too little attention
to the weakness of the experimental approach and the statistics being used
relative to the variance in the data. Some experiments, such as the
earthworm-incubation studies, were especially questionable in interpretation.
This study cannot distinguish between a test of "natural" versus "unnatural
habitat" and treatment versus control, because in the control site the earth-
worm species being incubated was very rare.
CONCLUSIONS
The utility of this research for policy-making is compromised by a failure
to ensure that BAC} was properly applied, by the problem of pseudoreplication
and the fact that at best only one control site was compared with one treatment
site (which differed substantially from the control site before antenna activa-
tion), and by a statistical failure to disentangle temporal trends due to antenna
activation from other temporally varying environmental factors. Any effects
of ELF EMFs were small, compared with the total variation of the processes
measured over the Il-year study; but the study included drought years (likely
to be important to soil macrofauna), and it might not be consoling to learn that
variation due to ELF EMFs is minor in comparison with the variation caused
by a severe drought.
SOIL AMEBAS
PROJECT PROPOSAL
This study, carried out over a period of more than 10 years starting in
1983, records data on populations of soil amebas from two treatment sites near
the antenna (one next to the ground terminal and one under the antenna) and
a control site about 15 km away, where 76-Hz EMFs were at most one-tenth
as large. The studies focused on the ameba Acanthamoeba polyphaga and
included counts of organisms in the soil (population sizes), growth-rate mea-
surements in situ in culture vessels designed to match ELF-EMF exposures in
the soil, and species present and determinations of genetic heterogeneity based
on isoenzyme analyses.
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EVALUATION OF FINAL REPORTS
SPECIES SELECTION
109
Acanthamoeba polyphaga is one of the more common and already well-
studied species of soil amebas that occur near the Michigan transmitting facil-
ity. Soil amebas are micropredators, and variations in total counts are thought
to reflect differences in quality and quantity of food available, especially bacte-
ria. They are close to the bottom of the food chain and thus might be highly
indicative of effects at that level. Measurements of total bacteria in the soil,
a classically indeterminate value, were attempted with a modification of the
acridine orange direct-counting technique; numbers were around lO9/g of soil
but were highly variable, so attempts to use this technique to explain variance
in soil-ameba numbers were abandoned.
SELECTION OF RESPONSE VARIABLES
The three principal response variables, as noted above, were counts of
organisms in the soil, growth-rate measurements, and determinations of spe-
cies present and the genetic heterogeneity. These seem well suited to address
the overall study from an ecological vantage point, in that they embrace the
static situation, the dynamic growth question, and possible genetic effects
according to a well-established criterion.
EXPERIMENT DESIGN AND IMPLEMENTATION
Biologic Sampling Techniques
The sampling techniques were well described and appear to have been
carried out with professional competence. Similar experimental procedures
were used for samples from the control and treatment sites.
Physical Measurements and Sites
The physical measurements of the fields and currents at both treatment
and control sites were made in cooperation with ITTR] personnel and are well
described in the report. Extensive measurements were also made of soil
chemistry and moisture, the latter having a substantial effect on the biologic
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systems measured. Data on temperature were collected and are presented in
full.
The sites for sampling the organisms were selected in cooperation with
IlTR} personnel. All sites had a similar 60-Hz EMF background, and the
control site had 76-Hz EMF intensities no more than one-tenth those at the
treatment sites. The ground treatment site was 39 m from the ground termi-
nal, whereas the antenna treatment site was about 40 m from the north-south
leg of the antenna. The control site was 15 hen south of the ground treatment
site.
Statistical Methods
One-way analysis of variance (ANOVA) was used to detect differences
in total-ameba and cyst counts at the three sites. The before-and-after,
control-and-impact (BACT) analysis was used for the log maximal ameba
counts and the maximal cyst counts and in the measurements of genetic diver-
sity.
CONCLUSIONS
No population-density differences were found between antenna treatment,
ground treatment, and control sites. In addition, growth rates of Acanthamoe-
bapolyphaga did not differ between sites, and genetic-diversity studies failed
to reveal differences between sites. The only statistically significant difference
found was in conditions before and after antenna operation; there was a small
but statistically significant difference in maximal population densities between
the control site and ground treatment site, but by the same method of analysis
no differences between the control site and the antenna treatment site or be-
tween the antenna and ground treatment sites.
The study appears to have been carried out carefully and competently.
The inherent variability in the data was great and changes due to temperature
and moisture were large, so small effects would not have been detectable. But
the study results constitute convincing evidence that large-scale ELF effects
did not occur over the time that the study was carried out.
It should be noted that the antenna was fully operational only during the
last years of the study and that even then there were down periods. Neverthe-
less, this study was adequate for the questions being asked.
Representative terms from entire chapter:
monitoring program
