You are here: Home > Activities > Meetings > 2002 > abstracts > Monday >
Society for Conservation Biology: 2002 Annual Meeting

Abstracts

< Go Back

Society for Conservation Biology: 2002 Annual Meeting



Society for Conservation Biology 16th Annual Meeting July 14-July 19 2002
co-hosted by DICE and the British Ecological Society


Abstracts for Spatial Ecology and Conservation
Session One

Monday 15th July, 10.15 - 12.15, Eliot Lecture Theatre 2

Chair: William Kunin




(BLOCK CAPITALS indicate the presenting author)

10.15 - 10.30
OGUGE, NICHOLAS OTIENOH, Richard Odhiambo and Bernard Agwanda. Department of Zoology, Kenyatta University, P.O. Box 43844, Nairobi, Kenya, <oguge@duke.edu>.

COMMUNITY PATTERNS IN SMALL MAMMALS DISTRIBUTION IN MOIST FORESTS OF SOUTHEAST KENYA

As a step towards setting conservation priorities for declining moist forests in southeast Kenya, we assessed small mammal diversity and distribution. These habitats are under severe pressure due to increased demand on forests products and arable land, yet impact on biodiversity is not well documented. Over an eight-month period, we used a combination of box and pitfall traps to study 14 forest fragments in five geographic areas ranging between 3° 28´ - 4° 10´ S and 38° 28´ - 39° 26´ E. We documented 29 small mammal species including: Muridae (10), Myoxidae (2), Cricetomyinae (2), Dendromurinae (2), Protoxerini (1), Myosciurini (1), Soricidae (10), and Macroscelidae (1). Praomys taitae, a murid, had the widest distribution, being recorded in 12 fragments. Twelve species were limited in distribution each to one forest fragment, of which nine were in three intact forests (Mbololo, Kyulu and Kasigau). Degraded forest patches showed invasion by woodland, savannah and commensal rodents. Our record of Crocidura cf. selina in Kyulu Hills is the first outside Mabira forest in Uganda where it is considered endemic and endangered. Our study provides new ranges to six species and is thus of significance to the biogeography and conservation of forest small mammals regionally.

10.30 - 10.45
GRANT, RINA C. and Mary C. Scholes. School of Animal, Plant and Environmental Sciences, University of the Witwatersrand <northernp@parks-sa.co.za>.

HIGH NUTRIENT PATCHES IN THE SAVANNA LANDSCAPE AS KEY RESOURCE AREAS OF WILD HERBIVORES.

It is hypothesised that intensely utilized habitats, rather than the entire landscape, form the resource base that determines the number and distribution of herbivores, and that a difference in available nutrients would explain differences in utilization. Three habitats (two intensely utilized and one poorly utilized) were sampled in geologically stratified nutrient-rich and nutrient-poor soils at the beginning and end of the growth season. Total nitrogen, phosphorus, sodium and calcium and N mineralization rates were determined in soil samples and in forage samples collected in the habitats. Phosphorus and nitrogen were also determined in dung samples of the common grazers utilizing these habitats. Intensely utilized sites had a significantly higher percentage of grazed grass tufts and dung heaps. Results thus far indicate significantly higher N mineralization rates at the beginning of the growth season and in the nutrient-poor soils. Significant differences between habitats were only shown in the area with the lowest mineralization rates. Nutrient-rich landscapes had higher available P. Areas with higher N mineralization rates had the highest animal numbers at the end of two years of below average rainfall, while the highest animal numbers in average years occurred on the nutrient-rich soils with higher available P.


10.45 - 11.00
HOODICOFF, CORINNA, Karl Larsen and Richard Weir. Department of Biology, University of Victoria, Victoria, British Columbia V8W 3N5, Canada, corinnah@uvic.ca (CH), Department of Forestry and Natural Resource Sciences, University-College of the Cariboo, Kamloops, British Columbia V2C 5N3, Canada (KL), and Artemis Wildlife Consultants, Armstrong, British Columbia V0E 1B0, Canada (RW).

LANDSCAPE MOVEMENTS AND CONSERVATION OF BADGERS (TAXIDEA TAXUS) IN BRITISH COLUMBIA, CANADA.

North American badgers are at the northern limit of the species distribution in British Columbia, Canada. This badger population (Taxidea taxus jeffersonii) is endangered and suffering losses due to grassland habitat degradation, prey decline, and road mortality. Here I report the results of a 2-year study on badger movement across the fragmented landscape and suggest conservation initiatives to address road mortality. Using radio-telemetry, I found striking differences in the individual badger habits. Home ranges vary between 7.6 to 257 km2 (100% MCP) and are up to 100 times that reported in studies from the United States. Using an index of aggregation and random walk model, I have illustrate that burrow locations are aggregated in core areas across each home range. These core areas consist of 2 to 6 patches and represent 20% of home range areas on average. Long-distance, nocturnal movements between core areas and other locations are common; animals move as far as 14 km in 4 hours and crossed large obstacles (e.g. highways and rivers) multiple times during one night. Fragmentation of suitable habitat and prey availability is undoubtedly affecting movement between patches, and the scale at which these animals perceive their landscape must be considered.



11.00 - 11.15
PACHECO, JESUS, Gerardo Ceballos, Rurik List, and Erika Marcé. Instituto de Ecología, Universidad Nacional Autónoma de México, Ap. Postal 70-275, 04510, Mexico, D.F., México, <jpacheco@miranda.ecologia.unam.mx>.

HABITAT FRAGMENTATION, REGIONAL BIODIVERISTY, AND CONSERVATION OF BLACK-TAILED PRAIRIE DOGS (CYNOMYS LUDOVICIANUS) IN MEXICO

Prairie dogs play an important role in natural communities and several studies have shown that they are a keystone species in North American grasslands, essential to the maintenance of the biotic integrity of their ecosystem. Many species of plants, vertebrates, and invertebrates benefit from the disturbance and heterogeneity caused by prairie dog activities. The Janos-Casas Grandes black-tailed prairie dog complex (JCG) is located in the grasslands of north-western Chihuahua, Mexico, approximately 20 km south of the USA-Mexico border. This is the largest continuous prairie dog complex in North America. We documented large scale geographic range changes in the prairie dog colonies from 1988 to 2000. Total distribution area was reduced by 46%, and the area occupied by prairie dog towns was reduced by 60%. We registered in total 45 prairie dog towns ranging in size from one to 15,076 ha, and covering an area of over 20,000 ha. Removal of prairie dogs has resulted in the fragmentation of towns with the consequent invasion of bushes and mesquite scrub over former grassland, and a decrease in regional vertebrate diversity. The preservation of this area is an unparalleled opportunity to maintain the regional and hemispheric biodiversity.



11.15 - 11.30
PINTEA, LILIAN and Anne Pusey. Conservation Biology Program, Ecology 100, University of Minnesota, 1987 Upper Buford Circle, St. Paul, MN 55108, USA, <pint0020@umn.edu> (LP), Department of Ecology, Evolution and Behaviour, University of Minnesota, 1987 Upper Buford Circle, St. Paul, MN 55108, USA (AP).

PEOPLE, CHIMPS AND PIXELS: LINKING LAND COVER CHANGE AND 40 YEARS OF CHIMPANZEE BEHAVIOUR IN GOMBE

Chimpanzees, our closest living relatives, are declining alarmingly in abundance and distribution. Members of a chimpanzee community spend their time in parties of fluctuating size and the adult males defend territory against neighbouring communities. Habitat loss and fragmentation are likely to disrupt the balance of power between adjacent communities causing group extinction and loss of genetic diversity. We use GIS to link remote sensing and 40 years of chimpanzee observations in Gombe National Park, Tanzania to determine how habitat changes within and outside the park correlate with changes in chimpanzee social structure. Since the park was established in 1968, its vegetation has gradually recovered while deforestation severely increased outside protected areas influenced by refugees from DRC and Burundi. Two chimpanzee communities at the northern and southern borders have shown drastic decreases in group and home range size. The range and party size of the middle community has fluctuated over 40 years but has constantly increased in the last 10 years, corresponding with the recovery of vegetation and decline of the other communities. Thus habitat change has had an unequal effect on chimpanzees in Gombe, threatening the extinction of the peripheral communities. Such changes complicate the challenge of conserving small populations.



11.30 - 11.45
DEHGAN, ALEX. Committee on Evolutionary Biology, The University of Chicago, 1025 East 57th Street, CH402, Chicago, IL 60637, USA, and Division of Mammals, Field Museum of Natural History, 1200 S. Lake Shore Drive, Chicago, IL 60637, USA, <adehgan@midway.uchicago.edu>.

THE BEHAVIOR OF EXTINCTION: LEMUR POPULATIONS IN FRAGMENTED HABITATS OF S.E. MADAGASCAR

We do not understand why some animals persist in the face of fragmentation, while others disappear. This study seeks to explain the differential susceptibility of animals with complex behaviours to habitat fragmentation. To do so, we predicted that behaviour, in particular social structure and foraging, and phylogenetic constraints on such behaviour (the extent of behavioral plasticity), determined lemur incidence in habitat fragments. To test these predictions, we collected incidence and demographic data on 12 species of lemurs in habitat fragments in the S.E. rainforests of Madagascar. We also collected extensive behavioural and physiological/morphological data on three lemur species predicted to differ in their degree of behavioural plasticity. Finally, we examined the incidence of lemur predators (both terrestrial and aerial), the fragment’s botanical makeup, the availability of primary lemur foods, historical species incidence, and hunting practices as alternative causal agents. We found that species strongly differed in their response to fragmentation. These responses were non-random, highly nested, and reflected the species’ differential plasticity. The behavioural and physiological data further supported our predictions. The distribution of predators, lemur body mass, food availability within the fragment, the fragment’s botanical makeup, and hunting pressures were not significant in explaining species incidence.



11.45 - 12.00
CHIN, CYNTHIA. Wildlife Conservation Society, No.7, Jalan Ridgeway, 93200 Kuching, Sarawak, Malaysia, <dozer@pd.jaring.my>.

HUNTING PATTERNS AND WILDLIFE ABUNDANCE IN FORESTS OF DIFFERENT ACCESS IN THE UPPER BARAM, SARAWAK (BORNEO)

The problem of roads in previously inaccessible forest areas has proven to be a serious conservation issue in tropical forests worldwide. While increased access allows greater mobility for rural communities, and for technology to reach these communities, it has also led to greater hunting pressures on wildlife in tropical forests. This study examined the effects of logging access on hunting patterns and wildlife abundance in three study sites in the Upper Baram region of Sarawak. The hypothesis tested was that populations of game animals increase in areas of tropical forest following the advent of logging roads. Surveys were conducted in similar unlogged habitat at three sites. All areas were occupied by Penan communities. The main difference between study sites was level of access via logging road. Data were collected from July 1999 to June 2000. Data collection lasted from seven to 14 days each trip. Surveys on the hunting patterns of each community and line transect surveys for wildlife were done. Results showed that as levels of accessibility increased, hunting pressure increased, and hunting success decreased; and that as hunting pressure increased, wildlife diversity and relative abundance declined. Thus, the null hypothesis was disproved.



12.00 - 12.15
KUNIN, WILLIAM E., Stephen Hartley and Thanasis Kallimanis. Centre for Biodiversity and Conservation, University of Leeds, Leeds LS2 9JT, UK w.e.kunin@leeds.ac.uk (WEK, SH), Aristotle University of Thessaloniki, Greece, (TK).

SCALE, RARITY AND EXTINCTION RISK

The rarity or abundance of species is intrinsically scale-related. Using data from cross-scale field surveys of rare and scarce British plants, we demonstrate that species may differ dramatically in relative abundance depending on the scale of analysis. These differences in the way abundance changes with scale have implications for extinction risk. By modelling different scale disturbance processes, we demonstrate that the relative importance of disturbances of different scales can shift the relative risks to sparsely and patchily dispersed species.