Dynamics of the NW Atlantic population of the spiny dogfish are investigated. The population underwent a three-fold increase in abundance since the early 1970s. This study aims to gain understanding of the underlying population dynamics of spiny dogfish, and the possible changes of some critical life-history parameters through time, that might explain the overall increasing trend in abundance. The first step consisted of estimating the abundance of the different life-stages of the population. The pre-adult female, adult male and adult female life-stages were identified and decomposed from length frequency modes. Area was then used for stratification of the log-transformed abundance estimates of each life-stage. MULTIFAN was used to assess differences in the growth of juvenile spiny dogfish. The growth rate was shown to increase from 1968-1971 to 1976-1979 and then decrease to 1988-1990. The hypothesis that these changes were density-dependent was tested and, with the exception of age-2, mean lengths at ages 1 through 5 were significantly correlated with the indices of abundance of the juveniles. Fecundity and size at maturity were also investigated. Literature data from samples collected since 1942 was re-analyzed and compared with more recent data collected during the 1980s and 1991. Significant negative correlations were detected between fecundity and abundance for most size-classes considered, and positive, mostly non-significant correlations were found between fecundity and mean weight. Changes in size at 50% female maturity were also detected and were suggested to be the result of density-dependent changes in juvenile growth. Several recruitment-stock relationships were investigated. Biomass estimates for females were smoothed using an ARIMA time series model on the logarithm of the indices of abundance. A Ricker model, with a temperature-dependent correction, was accepted as the best predictor of recruitment. A Leslie matrix model incorporating density-dependent sub-models for growth, fecundity and recruitment was used to model changes in reproductive dynamics. The model suggested that the observed increase in abundance is at least partially explained by changes in juvenile growth observed during the early-1970s. These changes later resulted in increased mean size at maturity, and subsequent fecundity.

I investigated the relationship between food abundance and black bear reproductive success. Black bear reproductive potential had been hypothesized to be related to natural food abundance in other studies but the effect had not been tested. Pregnant females should select dens of maximum thermal efficiency to conserve body fat used for thermoregulation. If this were so they could allocate more depot fat to lactation. I examined data on natal den type (open nest, brushpile, covered) and subsequent survival of cubs in Massachusetts and Minnesota over 11 and 13 years, respectively. I could not detect any differences in cub survival but the power of tests was low (power = 0.139 to 0.258). I could not predict either litter size or MFYS from environmental and harvest variables. When natural food abundance was low black bears used cornfields intensely and did not differ in body weight from high food years. Litter size and MFYS were related to litter order; first litters were smaller and had lower survival than subsequent litters. Sixty percent of Massachusetts females had their first litter at 3 years old. Twelve of 20 first litters were of single cubs and 10 of 12 first litters were totally lost. I hypothesized that female black bears operated according to the life history theory of tradeoffs between present and future reproduction. Having cubs is not very costly to bears, raising them is. Thus, females had cubs at an early age (3 years old) but often could not find enough food in spring to both lactate and continue structural growth. Thus, first litters were usually lost. I provide the first direct test of the hypothesis of the effect of diet quality on milk composition and cub survival in free-ranging bears. Milk composition differed between years of varying spring diet quality. Milk fat was lower when diet fat was low but MFYS was not different between the high fat and low fat years. I conclude that in Massachusetts, and likely most of eastern North America, natural food abundance has little effect on bear reproduction because bears can access alternate food sources.

Browsing by dense (>3–6 deer/km2) populations of white-tailed deer (Odocoileus virginianus) removes tree seedlings from the forest understory, making it difficult for the forest to regenerate if the overstory is damaged or removed. Hay-scented fern can invade the forest understory where deer have damaged and removed other plants. These ferns form dense (90–100 fronds/m2) colonies that cover the forest floor with a thick root mat and form a canopy 60–80cm tall. The ferns interfere with seedling growth, even if deer populations are reduced, because they limit germination sites and block light from reaching the forest floor. This research, conducted in the Quabbin Reservoir Watershed Forest, consisted of four studies that proposed to explain the current distribution of fern colonies, identify specific ways in which past deer browsing and current fern growth affected the germination and growth of several common local tree and shrub species, and evaluate mechanical treatments for hay-scented fern control. By sampling pine plantations thinned at various times over a 30 year period, it was determined that overstory thinning followed by a period of at least 15 years of excessive browsing was required for fern colonies to grow so that understory tree seedling regeneration was blocked throughout a forest stand. Rubus is able to grow through hay-scented fern and expand at the expense of fern colonies. A study of the soil seed bank determined that heavy deer browsing may be associated with depletion of Rubus spp. seeds in the soil. This may slow the recovery process. A study of seedling growth and phenology indicated that seedlings that grow above the fern canopy, Rubus, black birch and white pine, begin photosynthesis early in the spring before annual fern growth blocks the light to the forest floor. In the last study, it was found that while the root mat reduces germination, it does not stop seedling growth to the extent that the intact fern canopy does. Rubus, black birch, and white pine were able to germinate and grew well even with the root mat intact. Breaking up the root mat without removing it increased fern growth in the next growing season.

Snow leopard ecology, distribution and abundance in Mongolia were studied between 1993 and 1999. I placed VHF and satellite radio-collars on 4 snow leopards, 2 males and 2 females, to determine home ranges, habitat use, movements, and activity. Home ranges of snow leopards in Mongolia were substantially larger than reported elsewhere. Males ranged over 61–142 km2 and female 58 to 1,590 km2. Cats had crepuscular activity patterns with daily movements averaging 5.1 km. Intraspecific distances averaged 1.3 km for males to 7.8 km for males. Leopards selected moderately to very-broken habitat with slopes >20°, in areas containing ibex. Leopard distribution and abundance was determined using sign surveys. Leopard range in Mongolia is approximately 103,000 km2 but cats are not uniformly distributed within that range. High-density areas include the eastern and central Transaltai Gobi and the northern Altai ranges. Relative leopard densities compared well with relative ibex densities on a regional basis. A snow leopard conservation plan was drafted for Mongolia that identifies problems and threats, and provides an action plan. Wild Bactrian camels occur in the Great Gobi National Park (GGNP) and are thought to be declining due to low recruitment. I surveyed camels by jeep and at oases, observing 142 (4.2% young) and 183 (5.3% young) in 1997 and 1998. Current range was estimated at 33,300 km2. Some winter and calving ranges were recently abandoned. Track sizes and tooth ages from skulls were used to assess demographics. A deterministic model was produced that predicts camel extinction within 25 to 50 years under current recruitment rates and population estimates. Gobi brown bears are endemic to Mongolia and may number less than 35. Three population isolates may occur. I collected genetic material from bears at oases using hair traps. Microsatellite analyses of nuclear DNA determined sixteen unique genotypes, only two of which occurred at more than one oases. Genetic diversity was very low with expected heterozygosity = 0.32, and alleles per locus = 2.3. Mitochondrial DNA sequences were compared to other clades of brown bear and found to fall outside of all known lineages.

Macro- and micro-habitat associations of small mammals in seral aspen-birch and mature red spruce habitats in Acadia National Park, Maine, were studied by live-trapping during the summers of 1987 and 1988. The aspen-birch habitat was structurally more diverse than the mature conifer habitat, but diversity, richness, and evenness of species of small mammals were not different between habitats. Blarina brevicauda, Sorex cinereus, Tamias striatus, and Peromyscus leucopus exhibited preference for seral hardwoods, whereas Tamiasciurus hudsonicus showed preference for the red spruce habitat. Most species in the aspen-birch habitat exhibited some degree of microhabitat selection and used microhabitat separate from other species. Small mammals in the red spruce habitat were less selective. Microhabitat used by a species and segregation by microhabitat among species varied between years in both habitats and appeared to be related to intraspecific interactions. Microhabitat use by sexes of Clethrionomys gapperi, P. maniculatus, and P. leucopus in the aspen-birch habitat was related to degree of habitat specialization. A spatial simulation system was developed to examine the responses of habitats of B. brevicauda, P. leucopus, T. striatus, and T. hudsonicus over time to varying levels of disturbance in the western section of Acadia National Park. The system consists of a raster-based data base containing descriptors of cover types, and models of vegetative succession and disturbance by windthrow and wildfire. Simulation experiments were conducted without disturbance, under three levels of windthrow, and with two sizes of wildfires (100 and 500 ha) at the three levels of windthrow. Occupancy of available habitat was based on the dispersion of a species during the previous simulation interval, the dispersal distance of a species, and patch size. Habitat for species associated with hardwoods increased with the rate of disturbance. Regardless of disturbance size or rate, each species was able to occupy almost all of its available habitat over a 300 yr period owing to the dispersion of habitat patches created by windthrow. Results suggest that windthrow alone can produce long-term spatial diversity of wildlife habitats in Acadia.

Conservation of biological diversity has become a priority in the natural resource management planning process, yet information on the effects of management practices beyond the scale of single stands is lacking. The objective of this study was to determine whether timber management was compatible with the goal of maintaining forest bird species diversity in the northern hardwoods forest type. Twelve 64-ha study areas, 6 managed for quality sawlogs and 6 not managed for timber, were selected in the White Mountain National Forest, New Hampshire. Managed areas included approximately 60% sawtimber, 20% pole, and 20% sapling even-aged northern hardword stands while unmanaged areas were 100% sawtimber stands $>$80 years old. Young stands were $<$20 ha in size; older stands ranged from about 10 to 140 ha. Bird species abundances were determined in each area from 8-minute counts in June 1989-90 at 16 points spaced 200 m apart. Bird species diversity, as measured by Shannon-Weaver, Simpson, log series alpha, and species richness indices, was greater (P $<$ 0.005) on managed areas than on unmanaged areas. Managed areas included a total of 53 species compared to 33 on unmanaged areas. All 33 species present on unmanaged areas were also present on managed areas. Of 19 species with mean abundances $>$1 individual/area and coefficients of variation $<$50%, the ovenbird was the only species more abundant (P $<$ 0.10) on unmanaged areas, yet ovenbirds were the third most abundant species on managed areas. American redstart, rose-breasted grosbeak, and veery were all more abundant (P $<$ 0.05) on managed areas. The above results suggest small scale timber harvesting can increase forest bird species diversity without loss of any species. These results apply to extensively forested areas of northern hardwoods in the northeastern United States and may not apply in other areas or in areas where harvesting practices are more intensive. Analysis of minute-by-minute bird counts and evaluation of bird surveys for unmanaged areas suggested point counts should be 8-minutes in duration at points $\ge$400 m apart. Travel time between points had a greater effect on efficiency (individuals detected/hour) than count duration. Each point should be surveyed $\ge$3 times, and for a uniform habitat such as mature northern hardwood forest, a minimum of 24 points should be established.

No description available.

The food habits, movement and activity patterns, and habitat use of sympatric carnivores, and wildlife harvest and utilization, were studied at the Taohong Village, Jiangxi Province, southeastern China during 1992–1996. Food habits of four species of sympatric carnivores were studied by scat analysis. Crab-eating mongooses (Herpestes urva) had the most diversified diet that included many water-edge food items. Masked palm civets (Paguma larvata) consumed a large proportion of fruits. Both small Indian civets (Viverricula indica) and hog badgers (Arctonyx collaris) fed heavily on rodents. Though there was a certain degree of difference in habitat use among these species, the rather high diet overlap suggested that the population densities of these species were reduced to a very low level by constant harvest pressure and secondary poisoning so that the diet ceased to have relevant effect on the sympatry of these species. The food habits (based on scat analysis) of the sympatric dhole (Cuon alpinus) and wolf (Canis lupus ) showed that their depredation on the endangered Sika deer ( Cervus nippon kopschi), domestic animals and small carnivores was negligible. Telemetry studies showed that small Indian civets, masked palm civets, and crab-eating mongooses did not have permanent dens but moved among their numerous daybeds. Small Indian civets used daybeds among the bushes and grass on the ground while other species used underground dens exclusively. Small Indian civets and crabeating mongooses limited their activity to the foothills at low altitude, while masked palm civets included habitat of higher altitude in their home ranges. Both small Indian civets and masked palm civets were nocturnal, but the latter had a low activity level in the daytime. Crab-eating mongooses were active in the daytime. Ferret badgers (Melogale moschata) were strictly nocturnal. Their daybeds included both natural and man-made sites. The lack of direct conflict of interest with humans allowed them to live in close proximity to human settlement. Wildlife harvest during the 1992/96 harvest seasons was studied by the method of participant observation. Wildlife harvesters comprised 1.5% of the local population, and a few professional harvesters accounted for a large proportion of the game yield. Shotguns and two kinds of traps were the most common harvest methods used. Muntjac (Muntiacus reevesi) and hares (Lepus sinensis and L. capensis) were the most important game species. In spite of the steady increase in the price of wildlife parts, the game yields experienced a gradual decline due to reduced harvest efforts. Wildlife harvest was market-oriented and played an insignificant supplemental role in the local economy. Marketing channels for both pelt and game meat have been well established and are spreading. Wildlife harvest remained largely unregulated. The prospect of wildlife harvest at Taohong is discussed and recommendations to control harvest are proposed.

The ecology of Swietenia macrophylla and three associated tree species in seasonal tropical forests in Quintana Roo, Mexico were studied to improve the design of sustainable forest management methods. Seed production of 82 Swietenia trees from 15 to >100 cm diameter at breast height (DBH) was estimated by counting fruit pericarp segments beneath the tree crowns. The number of fruits/tree increased with DBH size and was related to increasing tree crown. Trees >75 cm DBH had significantly greater fruit production than smaller trees, and had a larger median seed dispersal distance (38 m) that was skewed to the west of the trees. Fruit production varied among the six-years, but did not reach the population variability or tree synchronicity that is found in masting species. The effect of 7%, 22%, and 45% sunlight and two soil moisture types on seedlings of Swietenia, Cedrela odorata, Cordia dodecandra, and Manilkara zapota were studied in shade houses in Quintana Roo, in order to examine plasticity of physiology, morphology, and biomass allocation as a background to understanding growth and competition in forest conditions. Some expected trends occurred in all species: leaf area ratio (LAR), specific leaf area (SLA), and foliar biomass allocation all increased with decreasing light. Good soil moisture increased height, diameter and biomass, therefore greater photosynthesis rates may be explained by more water availability. However, comparisons among species did not always show trends expected to be associated with different levels of shade tolerance. Shade tolerant Manilkara had the lowest total biomass, and the highest foliar biomass allocation, but did not have the expected high SLA because of its thick evergreen leaves. Shade intolerant Cedrela had the lowest foliar allocation, but compensated with the highest SLA, foliar nitrogen content, and photosynthetic rate. Intermediate/intolerant Swietenia had the highest biomass production of all species; it had high plasticity in foliar allocation such that there was little difference in total biomass among light levels. Intermediate/intolerant Cordia had lower plasticity in foliar allocation than Swietenia , so a lower LAR and substantially less total biomass in low light. It had thicker leaves and higher foliar nitrogen-area in high light.

Although ecotourism is touted as a tool to promote sustainable development and conservation of protected areas, it can have a negative impact on some species that it intends to protect. This dissertation explores the impacts of tourism on the breeding behavior and success of Atelornis pittoides , Madagascar's endemic pitta-like ground roller. Another goal is to understand the foraging and nesting requirements of this endangered bird. From 2000 to 2003, I studied the morphology, habitat use, distribution, foraging behavior, nesting-habitat selection, breeding behavior, and breeding success of Atelornis pittoides (Brachypteraciidae, Coraciiformes) at three different study localities in the Ranomafana National Park. Data were collected using line transects, point counts, mist netting, and direct observation. Characteristics of preferred and rejected habitats were measured at each of the three study localities. Habitat disturbance was evaluated by direct observation and park records. Talatakely forest had suffered the greatest disturbance; Vohiparara had suffered moderate disturbance, and Parcelle 1 had suffered little disturbance (and supported no ecotourism). The breeding success of Atelornis was found to be jeopardized by natural- and human-induced habitat disturbance. It decreased in areas of heavy tourism, in years marked by heavy tourism, and for nests built close to tourist trails. Nest predation rates increased with increasing tourism. There were differences in the calling behavior of birds at the three localities; in the most disturbed habitats, the birds called less frequently, particularly in the middle of the day (when tourists are likely to draw predators to their nesting sites). Atelornis was found to be selective in its choice of nesting sites. There were significant differences in vegetation structure and composition, as well as other habitat characteristics (e.g., soil exposure, presence of fallen trees, local topography), between preferred and rejected habitats. In general, nesting habitat selection is related to predator avoidance, access to ideal foraging habitat, and avoidance of competition with conspecifics. Long-term pair bonding and nest habitat fidelity (from year to year) was demonstrated, for the first time, in this study. A minor but statistically significant amount of sexual dimorphism was also demonstrated, and interpreted within the context of foraging and breeding adaptations.