Environmental Conservation Faculty Publication Series

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https://hdl.handle.net/20.500.14394/242

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Relative importance of early-successional forests and shrubland habitats to mammals in the northeastern United States
(2003-01-01) Fuller, TK; DeStefano, S
The majority of the 60 native terrestrial mammal species that reside in the northeastern United States (US) utilize resources from several habitats on a seasonal basis. However, as many as 20 species demonstrate some preference for early-successional forests, shrublands, or old-field habitats. A few of these (e.g. lagomorphs) can be considered obligate users of these habitats, and the specialist carnivores (e.g. felids) that prey on them may consequently also prefer such habitats. Other mammal species that prefer these habitats certainly depend on them to lesser and varying degrees; thus, the consequences of reducing or eliminating early-successional forests, shrublands, or old-field habitats across the landscape will likely have varying demographic consequences, and thus importance, to those species.
Ferret badger Melogale moschata activity, movements, and den site use in southeastern China
(2003-01-01) Wang, HB; Fuller, TK
We conducted field studies of ferret badgersMelogale moschata (Gray, 1831) during March–November 1994 and May–July 1996 at Taohong Village in southeastern China. Capture data suggested that they gave birth in May, and telemetry data on 11 individuals indicated that they were nocturnal. Size of resting home ranges (daybed locations only;n ≥ 20 re-locations) of 6 individuals averaged 11 ha (range 1–25 ha) and no sex-specific differences in size were detected. Distances between daily resting sites averaged 101 m, but ferret badgers often (51% of occasions) returned to sites used the previous day. Ferret badgers readily used a variety of shelters as daybeds, including rodent dens (47%), firewood stacks (20%), open fields (17%), and rock piles (5%) around houses. Key words Melogale moschata -activity-China-den-home range-movements.
Food habits of four sympatric carnivores in southeastern China
(2003-01-01) Wang, H; Fuller, TK
The food habits and diet overlap of four sympatric small carnivore species were studied in a rural agricultural area of southeastern China by analyzing 37-112 scats of each species. Small Indian civets (Viverricula indica) ate mostly mammals, with moderate insect and plant components. Crab-eating mongooses (Herpestes urva) ate mammals, reptiles, insects, and crustaceans. Masked palm civets (Paguma Larvata) ate some mammals and insects, but mostly plants (fruits). Hog badgers (Arctonyx collaris) ate more mammals and gastropods than the other carnivores. Although diets were distinctly different, diet overlap among these species was relatively high and we speculate that this might reflect low population density due to harvesting by humans and secondary poisoning, and/or high rodent densities near agricultural-lands.
Demographic responses of Virginia opossums to limitation at their northern boundary
(2004-01-01) Kanda, LL; Fuller, TK
The precise response of a population at its distributional edge to the limiting extrinsic factor should be mediated by the demography of the species. We applied this principle to understanding the northern distributional potential of the Virginia opossum (Didelphis virginiana Kerr, 1792). We reviewed the literature for demographic data that we then used to build model populations. Juvenile over-winter survival was adjusted to determine the survival necessary for a stable population. To put the results in the context of life-history strategy and ecological niche, we built models for two other medium-sized mammals with similar distributions, the raccoon (Procyon lotor (L., 1758)) and the muskrat (Ondatra zibethicus (L., 1766)). Northern raccoon populations may sustain juvenile winter survival rates of <0.50 because adult females live to reproduce in multiple years. Muskrat juveniles may need a winter survival rate of only 0.40 in average years because reproduction is very high. In contrast, young northern opossums need a survival rate of 0.81 over winter to compensate for low prewinter survival. Raccoons and muskrats, through different life-history strategies, should be able to expand their northern distribution to the winter-induced physiological limit. However, opossum populations should fail before the average individual physiological limit is reached.
Assessing an American Marten, Martes americana, reintroduction in Vermont
(2003-01-01) Moruzzi, TL; Royar, KJ; Grove, C; Brooks, RT; Bernier, C; Thompson, FL; DeGraaf, RM; Fuller, TK
During October-December 1989-1991, biologists from the Vermont Fish and Wildlife Department and the USDA Forest Service reintroduced 115 (88 male, 27 female) American Martens (Martes americana) into the southern half of the Green Mountain National Forest. During the years of release, brief radio-contact was made with 9 of the 13 (8 male, 5 female) radiocollared animals, and several of these may have established residency. Results of winter track count surveys suggested the presence of at least four Martens in 1990. During winter 1994-1995, Trailmaster® cameras and boxed camera systems detected Martens at two, and Fishers (Martes pennanti) at 11, of 20 sites. During winter 1997-1998, Fishers were detected at 37 of 47 boxed camera sites, but no Martens were detected. During summer 1997 and 1998, no Marten photos were recorded at 285 pressure-plate camera stations in a larger area that included all Marten release sites. Although post-release monitoring may have been insufficient to definitively confirm Marten presence, results from the 1997 and 1998 camera surveys indicate that a viable population of Martens was not established in southern Vermont, perhaps due to competition with Fishers.
Reproduction, neonatal weights, and first-year survival of Mongolian gazelles (Procapra gutturosa)
(2005-01-01) Olson, KA; Fuller, TK; Schaller, GB; Lhagvasuren, B; Odonkhuu, D
Mongolian gazelles Procapra gutturosa were observed, hand-captured and radio-monitored in the eastern steppe of Mongolia during 1998–2003 to understand better their reproduction and survival. During early June, 92% (range = 87–96%) of adult (≥ 2 years old) females observed (mean n = 735/year) were pregnant, and nearly all gave birth during a 10-day interval (24 June–3 July) each year. Mean mass of neonate (1–2 days old) calves (mean n = 47/year) was greater for males than for females, and masses were directly correlated with mean monthly temperatures the previous winter (December–April). Survival during the first 10 days of life for 111 radio-marked neonate calves monitored during 2000–03 (n = 9–55/year) was 0.83 and did not seem to vary with birth weight. Also, deaths owing to hypothermia, abandonment, or unknown causes (interval cause-specific mortality rate = 0.16) outnumbered deaths owing to predation (0.02) during this interval. Survival rates were similar during the rest of the year (0.86 for 355 days) when most mortalities were owing to predation (interval mortality rate = 0.12 vs 0.01). Annual survival of calves was 0.71 (95% CI = 0.61–0.82). Gazelle births are highly synchronous, probably to take most advantage of the short summer growing season, and perhaps to avoid deleterious spring weather and to minimize predation. High fecundity and relatively high calf survival, especially during the first weeks of life, support the notion that gazelle populations can recover fairly quickly from demographic catastrophes.
Survival and cause-specific mortality of gray foxes (Urocyon cinereoargenteus) in southern California
(2005-01-01) Farias, V; Fuller, TK; Wayne, RK; Sauvajot, RM
From May 1997 to July 1999, 24 gray foxes Urocyon cinereoargenteus were radio-marked and their fates monitored in a natural area of southern California to identify rates of survival and cause-specific mortality, and thus to assess population sustainability. Pup (0.4–1.0 years old) foxes had an 8-month (September–April) survival rate (0.34) that was lower than the 8-month (0.77) or 12-month (0.58) estimates for adult foxes. Interference competition was evident; 92% (11/12) of fox mortalities were the result of predation by sympatric coyotes Canis latrans or bobcats Felis rufus. Also, five of seven gray fox mortalities were outside of, or on the border of, the home range of the killed fox. Calculations indicated that the fox population would remain stable if survival of pups during their first 4 months of life was 0.68 (vs 0.75 for adults during these months and 0.58 for older pups for 4 other months). This seems reasonable, yet sympatric carnivores, mainly coyotes, clearly influence the gray fox population in southern California.
Effects of spring acorn availability on black bear diet, milk composition, and cub survival
(2005-01-01) McDonald, JE; Fuller, TK
We investigated the role of changing abundance of spring foods on female American black bear ( Ursus americanus ) diet, milk composition, and cub survival in western Massachusetts. We hypothesized that diets would change, percentage milk fat would be higher, and cub survival would be higher in a year when overwintered hard mast was more abundant. We obtained paired samples of milk from 7 adult female bears across consecutive reproductive cycles during which spring diets differed; 1 year followed a bumper acorn ( Quereus rubra ) crop and estimated spring diets were ˃25% acorns; the other year followed an extremely poor acorn crop and spring diets were estimated to be 99% skunk cabbage ( Symplocarpus foetidus ). Postdenning milk was higher in fat (26.7% versus 18.2%; P = 0.0557) during the spring when acorns were abundant, but we did not identify any carryover affect to cub survival. We suggest that adult female black bears compensate for changes in food availability by eating greater volumes of alternative foods, and perhaps allocate resources primarily to milk production; the bears appear to be able to produce milk of adequate quality to sustain cubs, regardless of spring diet.
Movements and activities of snow leopards in Southwestern Mongolia
(2005-01-01) McCarthy, TM; Fuller, TK; Munkhtsog, B
Four adult (2M:2F) snow leopards (Uncia uncia) were radio-monitored (VHF; one also via satellite) year-round during 1994–1997 in the Altai Mountains of southwestern Mongolia where prey densities (i.e., ibex, Capra siberica) were relatively low (∼0.9/km2). Marked animals were more active at night (51%) than during the day (35%). Within the study area, marked leopards showed strong affinity for steep and rugged terrain, high use of areas rich in ungulate prey, and affinity for habitat edges. The satellite-monitored leopard moved more than 12 km on 14% of consecutive days monitored. Home ranges determined by standard telemetry techniques overlapped substantially and were at least 13–141 km2in size. However, the satellite-monitored individual apparently ranged over an area of at least 1590 km2, and perhaps over as much as 4500 km2. Since telemetry attempts from the ground were frequently unsuccessful , we suspect all marked animals likely had large home ranges. Relatively low prey abundance in the area also suggested that home ranges of >500 km2were not unreasonable to expect, though these are >10-fold larger than measured in any other part of snow leopard range. Home ranges of snow leopards may be larger than we suspect in many areas, and thus estimation of snow leopard conservation status must rigorously consider logistical constraints inherent in telemetry studies, and the relative abundance of prey.
Estimating the population density of Mongolian gazelles Procapra gutturosa by driving long-distance transects
(2005-01-01) Olson, KA; Fuller, TK; Schaller, GB; Odonkhuu, D; Murray, MG
Despite a ≥75% reduction in the geographic range of Mongolian gazelles Procapra gutturosa over the past 50 years, the species is still recognized as the most numerous large grassland herbivore in Asia. Its actual population size, however, is still disputed, and we therefore estimated its numbers in an 80,000 km2 area in the eastern steppe of Mongolia by driving long-distance (1,200–1,400 km) transect surveys during spring and autumn 2000–2002. Quantitative estimates of gazelle numbers are essential for understanding the causes of changes in the population, and thus devising conservation strategies to assure its long-term viability. Observed herds ranged in size from 1–4,000; among surveys, median herd sizes varied from 14–42. Density estimates varied from 10.7 gazelles km−2 in spring to 11.5 gazelles km−2 in autumn, with total population estimates of 803,820 (483,790–1,330,100 95% confidence interval) and 870,625 (499,432–1,491,278 95% confidence interval), respectively. Confidence limits were wide, and to obtain a coefficient of variation of 20%, transect lengths would need to be extended three- to four-fold. Until more efficient means for conducting population surveys can be implemented, driving long-distance transects, combined with distance analysis, seem to provide the best quantitative estimate of Mongolian gazelle populations.
Landscape associations of road-killed Virginia opossums (Didelphis virginiana) in central Massachusetts
(2006-01-01) Kanda, LL; Fuller, TK; Sievert, PR
Knowing the distribution of species at the landscape level can give insight into the proximate mechanisms determining the species’ range on a regional scale. We used a survey of road-killed animals to investigate landscape features associated with the presence of Virginia opossums (Didelphis virginiana) in central Massachusetts. Volunteers noted roadkilled opossums on their daily commutes through the Connecticut River Valley and surrounding towns in 2000 and 2002. We used a GIS to characterize both the locations of roadkills and random points according to elevation, land use, distance to open water, traffic speed and number of observers on the road and then used logistic regression to determine the association of roadkill sites with these variables. Dead opossums were found most often at low-elevation sites with less forest cover and more human development. Although the opossum usually is considered a habitat generalist found primarily in association with woodlands, opossums in central Massachusetts are not associated with woodlands and, instead, are most often found in and near urbanized areas.
Temperature sensor evaluation of opossum winter activity
(2005-01-01) Kanda, LL; Fuller, TK; Friedland, KD
To effectively monitor winter foraging activity by the cryptic, non-site-faithful Virginia opossum (Didelphis virginiana), we tested the use of small data-logging temperature sensors (iButton Thermachrons®, Maxim/Dallas SemiConductors, Dallas, Tex.) attached to a standard radiocollar on 3 opossums over the winter of 2000–2001. Two replicate sensors were required to clearly show time periods with cooler temperatures, an indication that the animal was outside the den. These foraging bouts were consistent with the available radiotelemetry data. Daily duration of foraging showed a strong negative relationship with ambient temperature, quantitatively documenting for the first time a phenomenon previously known only anecdotally. The iButton Thermachron seems to be an effective, low-cost, and low-effort technology for monitoring foraging activities of any animal that rests and forages in different temperature environments.
From the field: Implementing recovery of the red wolf - integrating research scientists and managers
(2005-01-01) Stoskopf, MK; Beck, K; Fazio, BB; Fuller, TK; Gese, EM; Kelly, BT; Knowlton, FF; Murray, DL; Waddell, W; Waits, L
The United States Fish and Wildlife Service (USFWS) developed guidelines for the composition and role of endangered species recovery implementation teams, but few teams have been established and their success has not been evaluated. Using the recovery program of the red wolf (Canis rufus) as a model, we describe the genesis, function, and success of the Red Wolf Recovery Implementation Team (RWRIT) in helping guide the establishment of a viable red wolf population in eastern North Carolina. In operation since 1999, the RWRIT meets bi-annually to review USFWS progress and provide recommendations aimed at maximizing success of species recovery. The team is comprised of 8 research scientists from disciplines including population genetics, canid ecology, population ecology, veterinary medicine, and captive management. Representation from each of these disciplines is deemed necessary for proper evaluation of recovery progress and assessment of future needs. Meeting attendance by the USFWS field management team ensures both proper reporting of past progress and future implementation of management recommendations. Over time, RWRIT members have assumed specific assignments for data analyses, further contributing to the recovery effort. Through the combined efforts of the USFWS field team and the RWRIT, the threat of introgression of coyote (Canis latrans) genes into the red wolf population has been substantially curtailed within the recovery area, and red wolf numbers and range have increased. The RWRIT serves as an example of a recovery implementation team that is successfully incorporating the principles of adaptive management and whose template could be adapted to other endangered species.
In search of forage: predicting dynamic habitats of Mongolian gazelles using satellite-based estimates of vegetation productivity
(2008-01-01) Mueller, T; Olson, KA; Fuller, TK; Schaller, GB; Murray, MG; Leimgruber, P
Ensuring that "authors" write
(2007-01-01) Fuller, TK
Pathogens, nutritional deficiency, and climate influences on a declining moose population
(2006-01-01) Murray, DL; Cox, EW; Ballard, WB; Whitlaw, HA; Lenarz, MS; Custer, TW; Barnett, T; Fuller, TK
Several potential proximate causes may be implicated in a recent (post-1984) decline in moose (Alces alces andersoni) numbers at their southern range periphery in northwest Minnesota, USA. These causes include deleterious effects of infectious pathogens, some of which are associated with white-tailed deer (Odocoileus virginianus), negative effects of climate change, increased food competition with deer or moose, legal or illegal hunting, and increased predation by gray wolves (Canis lupus) and black bears (Ursus americanus). Long-standing factors that may have contributed to the moose decline include those typically associated with marginal habitat such as nutritional deficiencies. We examined survival and productivity among radiocollared (n = 152) adult female and juvenile moose in northwest Minnesota during 1995–2000, and assessed cause of death and pathology through carcass necropsy of radiocollared and non-radiocollared animals.
Home range and social behavior of the endangered Tehuantepec jackrabbit (Lepus flavigularis) in Oaxaca, Mexico
(2006-01-01) Farias, V; Fuller, TK; Cervantes, FA; Lorenzo, C
We studied the home-range and core-area size and overlap of Tehuantepec jackrabbits (Lepus flavigularis) by radiotracking 32 individuals between May 2001 and April 2003 in savanna habitat in the Isthmus of Tehuantepec, Oaxaca, Mexico. Annual home-range and core-area sizes averaged 55 ha ± 8 SE and 8 ± 1 ha for 10 adults of both sexes using the 95% and 50% fixed-kernel isopleths, respectively. Seasonal home ranges varied widely for adults, from 15 to 111 ha for females and from 24 to 166 ha for males. Juvenile males had larger seasonal home ranges than did juvenile females (X̄ = 80 and 24 ha). For adult jackrabbits, seasonal home ranges were larger during the 1st year compared to those of the 2nd year of study (X̄ = 87 and 49 ha), particularly for females. Home ranges and core areas of Tehuantepec jackrabbits were comparable in size and overlapped between active periods (nocturnal and crepuscular hours) and inactive periods (diurnal hours). Adults overlapped their home ranges with 1–10 individuals. Home-range overlap among females was greater than among males. Females shared portions of their ranges with other females more frequently than did males with other males. Home-range and overlap analysis suggests that Tehuantepec jackrabbits have polygamous mating behavior and nonterritorial social organization.
Opportunistic use of camera traps to assess habitat-specific mammal and bird diversity in northcentral Namibia
(2008-01-01) Stein, A; Fuller, T; Marker, L
In northcentral Namibia, Waterberg Plateau Park (WPP) is a protected area that acts as a refuge for rare and endangered species, while the farmlands surrounding the Park are managed for livestock production, but support populations of wildlife for game farming, trophy hunting, and conservation. During June–October 2006, camera-traps were set within and surrounding WPP to assess leopard (Panthera pardus) density (n = 19 camera stations and 946 camera-trap-nights). Fortuitously, photographic results (2,265 photos of identifiable mammal (n = 37) and bird (n = 25) species) allowed us to assess aspects of species diversity and differences among the Park, the farmland areas along the Waterberg Plateau escarpment, and the flatlands surrounding the escarpment. Species composition among the three areas was markedly different, and made sense with respect to differences in habitat and management features. Camera-trapping efforts, although intended for a narrow purpose, may also provide a rather robust record of differences in mammal and bird diversity in adjacent habitats and can be incorporated into long-term monitoring programs.
Assessing Estimators of Snow Leopard Abundance
(2008-01-01) McCarthy, KP; Fuller, TK; Ming, M; McCarthy, TM; Waits, L; Jumabaev, K
The secretive nature of snow leopards (Uncia uncia) makes them difficult to monitor, yet conservation efforts require accurate and precise methods to estimate abundance. We assessed accuracy of Snow Leopard Information Management System (SLIMS) sign surveys by comparing them with 4 methods for estimating snow leopard abundance: predator:prey biomass ratios, capture–recapture density estimation, photo-capture rate, and individual identification through genetic analysis. We recorded snow leopard sign during standardized surveys in the SaryChat Zapovednik, the Jangart hunting reserve, and the Tomur Strictly Protected Area, in the Tien Shan Mountains of Kyrgyzstan and China. During June–December 2005, adjusted sign averaged 46.3 (SaryChat), 94.6 (Jangart), and 150.8 (Tomur) occurrences/km. We used counts of ibex (Capra ibex) and argali (Ovis ammon) to estimate available prey biomass and subsequent potential snow leopard densities of 8.7 (SaryChat), 1.0 (Jangart), and 1.1 (Tomur) snow leopards/100 km2. Photo capture–recapture density estimates were 0.15 (n = 1 identified individual/1 photo), 0.87 (n = 4/13), and 0.74 (n = 5/6) individuals/100 km2 in SaryChat, Jangart, and Tomur, respectively. Photo-capture rates (photos/100 trap-nights) were 0.09 (SaryChat), 0.93 (Jangart), and 2.37 (Tomur). Genetic analysis of snow leopard fecal samples provided minimum population sizes of 3 (SaryChat), 5 (Jangart), and 9 (Tomur) snow leopards. These results suggest SLIMS sign surveys may be affected by observer bias and environmental variance. However, when such bias and variation are accounted for, sign surveys indicate relative abundances similar to photo rates and genetic individual identification results. Density or abundance estimates based on capture–recapture or ungulate biomass did not agree with other indices of abundance. Confidence in estimated densities, or even detection of significant changes in abundance of snow leopard, will require more effort and better documentation.
Seasonal source-sink dynamics at the edge of a species' range
(2009-01-01) Kanda, LL; Fuller, TK; Sievert, PR; Kellogg, RL
The roles of dispersal and population dynamics in determining species' range boundaries recently have received theoretical attention but little empirical work. Here we provide data on survival, reproduction, and movement for a Virginia opossum (Didelphis virginiana) population at a local distributional edge in central Massachusetts (USA). Most juvenile females that apparently exploited anthropogenic resources survived their first winter, whereas those using adjacent natural resources died of starvation. In spring, adult females recolonized natural areas. A life-table model suggests that a population exploiting anthropogenic resources may grow, acting as source to a geographically interlaced sink of opossums using only natural resources, and also providing emigrants for further range expansion to new human-dominated landscapes. In a geographical model, this source–sink dynamic is consistent with the local distribution identified through road-kill surveys. The Virginia opossum's exploitation of human resources likely ameliorates energetically restrictive winters and may explain both their local distribution and their northward expansion in unsuitable natural climatic regimes. Landscape heterogeneity, such as created by urbanization, may result in source–sink dynamics at highly localized scales. Differential fitness and individual dispersal movements within local populations are key to generating regional distributions, and thus species ranges, that exceed expectations.

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