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Society for Conservation Biology 16th
Annual Meeting July 14-July 19 2002
co-hosted by DICE and the British Ecological Society
Abstracts for Population Monitoring
Session Two
Wednesday 17th
July, 15.30 - 17.30, Rutherford Lecture Theatre 1
Chair: Alison Williams
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timetable
(BLOCK CAPITALS indicate the presenting author)
15.30 - 15.45
RHODES, JONATHAN R., Andrew J. Tyre, Hugh P. Possingham and Clive A. McAlpine.
Department of Geographical Sciences and Planning, University of Queensland, Brisbane,
QLD 4072, Australia, <j.rhodes@uq.edu.au> (JRR), CSIRO Marine Research, P.O.
Box 120, Cleveland, QLD 4163, Australia (AJT), Department of Zoology and Entomology,
University of Queensland, Brisbane, QLD 4072, Australia (HPP), Department of Geographical
Sciences and Planning, University of Queensland, Brisbane, QLD 4072, Australia (CAM).
MONITORING WILDLIFE POPULATIONS: HOW USEFUL IS DISTRIBUTION DATA FOR DETECTING POPULATION
CHANGE?
Choosing monitoring strategies for detecting population change over time is a key
challenge for wildlife management. For many species, realistic options for monitoring
are restricted to surveys that only provide distribution data. However, the ability
of this data to be informative about population change is poorly understood. This
is particularly important for high profile species of international concern, such
as the koala. To assess the power of distribution data to detect population change
we built a simulation model for both a koala population and the monitoring process.
Demographic changes were simulated by 50% reductions/increases in adult or juvenile
mortality, with sampling from the landscape simulated for a set period after such
a change. Under the assumption of no observer error and up to 10% of the landscape
sampled, power to detect the resulting change in population size over a ten-year
period was often low. However, power could be increased dramatically by lengthening
the assessment period and altering stratification protocols. Further, optimal stratification
protocols were largely dependent upon assumptions about dispersal behaviour. These
results suggest the importance of considering life-history characteristics when designing
effective monitoring programmes. This has general applicability for the design of
monitoring strategies using distribution surveys.
15.45 - 16.00
SHULTZ, SUSANNE, Population and Evolutionary Biology Research Group, School of
Biology, Nicholson Building, University of Liverpool, Liverpool L69 3GS, UK <smshultz@liverpool.ac.uk>
USING GEOGRAPHIC VARIATION IN AFRICAN CROWNED EAGLE DIETS TO ASSESS PREY COMMUNITY
STRUCTURE
Composition and diversity of African crowned eagle diets from five geographic regions
across sub-Saharan African are related to mammalian prey community composition, habitat
type, and reserve size. Crowned eagle diet composition is also correlated with the
relative abundances and composition of different prey species. Although there is
not a perfect correlation between diet composition and prey abundance, once dietary
preferences for specific prey types are taken into account, it becomes possible to
use diet to estimate the composition of the prey community give a measure if community
health. Where traditional survey techniques (e.g. line transects) are difficult to
use (e.g. observing cryptic species, or in areas where there is heavy hunting pressure),
monitoring top predator diet composition is proposed as a complementary survey technique.
16.00 - 16.15
VARGAS, HERNAN and Hector Serrano 1)Wildlife Conservation Research Unit (WildCRU),
Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
Tel: 01865-271130 Fax: 01865-271211. E-mail: hernan.vargas@zoology.oxford.ac.uk
. 2) Charles Darwin Research Station, Isla Santa Cruz, Galapagos, Ecuador. Tel: 593-05-526146,
05-526147. Fax :593-04-564636. E-mail: hernanv@fcdarwin.org.ec.
(HV) Parque Nacional Galápagos, Isla Santa Cruz, Galápagos, Ecuador.
(HS)
IMPACT OF EL NIÑO AND CONSERVATION OF THE GALAPAGOS PENGUIN
One of the most difficult tasks in the conservation of threatened species is discriminating
natural from anthropogenic population changes. Examining results of 18 total counts
of the Galapagos Penguin conducted in the period 1970-2001 by the Charles Darwin
Research Station and the Galapagos National Park Service, we estimated that the current
(2001) population of penguins is approximately 40% of that of the early 70s. This
estimated decline in penguin numbers may be principally attributed to two strong
Niño events (1982-1983, 1997-1998) which were followed by crushes of 77% and
65%, respectively. Counts during the cold Niña years do not show that recoveries
have compensated the losses of the warm El Niño episodes. Counts after the
last 1997-1998 Niño do not indicate significant increases in the population.
Furthermore, comparisons of body condition of 418 penguins studied between 1996 and
2001 indicated that weights were lower during the Niño episodes than during
la Niña. Based on the recorded effects of El Niño and the slow recoveries
after the mid 80’s, especially at certain coastal zones heavily exploited by fisheries,
we conclude that the estimated decline and the slow recovery rate of penguins may
be due principally to the effects of El Niño. However, we can not rule out
a secondary effect caused by fisheries.
16.15 - 16.30
LITZKY, LAURA K., Roderick C. Hobbs, and Glenn R. VanBlaricom. Washington Cooperative
Fish and Wildlife Research Unit, University of Washington, Box 355020, Seattle, WA
98195, USA, <llitzky@u.washington.edu> (LKL, GRV), National Marine Mammal Laboratory,
7600 Sand Point Way, Seattle, WA 98115, USA, (RCH).
MONITORING THE AGE STRUCTURE AND RECOVERY STATUS OF COOK INLET, ALASKA BELUGA WHALES
(DELPHINAPTERUS LEUCAS) BY SKIN COLOR DETERMINATION
The Cook Inlet beluga stock has significantly declined since 1993, apparently due
to over harvest by native subsistence hunters. Harvest was suspended in 1999 and,
as a result, the fraction of mature animals (Mt) should increase if abundance recovers
(hunters targeted mature animals). Belugas are gray as juveniles, becoming white
with maturity. Thus, the fraction of white animals (Wt) is an index of Mt. Population
growth was modeled using a variable Leslie matrix and Mt estimated yearly from 1976-2050.
Averages from 5000 simulations estimated M1980 at 0.647 (CV 2.5%), M2000 at 0.559
(CV 3.7%), M2020 at 0.668 (CV 2.7%). The increase in Mt with recovery varied from
7-15% using a range of plausible life history parameters. To determine W2000, aerial-videos
of whales collected in June 2000 were analyzed with software that categorized animals
as gray or white. A controlled experiment provided color calibration via aerial-video
of life size beluga models. Image analysis estimated W2000 at 0.8109 (95% CI: 0.7613-0.8522).
W2000 may be positively biased due to low detection rate of small dark calves. Despite
the bias, the increase predicted for Mt with recovery, as indexed by Wt, should be
detectable if future measurements of Wt have similar variability to W2000.
16.30 - 16.45
JEFFERY, KATHRYN, Kate Abernethy, Caroline Tutin and Michael Bruford. Biodiversity
and Ecological Processes Group, School of Biosciences, P.O. Box 915, Cardiff University,
Cathays Park, Cardiff CF10 3TL, UK, (KJ, MB) <jefferyk@cf.ac.uk>,
Station d’Etudes des Gorilles et Chimpanzés, Lopé, Gabon and Centre
International de Recherches Medicale, Franceville, BP769, Gabon. (KA), Institute
of Biological Sciences, Stirling University, FK9 4LA, Scotland (KA, CT)
THE MOLECULAR ECOLOGY OF WESTERN LOWLAND GORILLAS IN GABON; A FORENSIC APPROACH TO
NON-INVASIVE STUDIES
Gabon's gorillas represent the largest remaining population of this threatened primate.
The gorilla population at the Lopé reserve in central Gabon has been extensively
studied for 19 years. However, due to the dense forest habitat sightings are infrequent
and habituation has only been partially successful in the case of one group. Little
is known of group ranging and overlap, dispersal and migration - crucial information
for informed reserve design. For ten years hairs have been regularly collected from
the night nests of approximately 50-60 gorillas in a 50 km2 study area. This unique
sample set provides us with a potential source of DNA to spatio-temporally track
individual gorillas and explore changes in group dynamics through time. However,
many problems are associated with PCR from naturally shed hair samples. I have developed
a sensitive, forensically reliable system of genetic identification, maximising the
potential for PCR success. Initial results suggest high levels of heterozygosity
and allelic diversity. The characterisation of three key groups will provide the
data to determine group and home range sizes, and to examine group structure, paternity
and relatedness within and between neighbouring groups.
16.45 - 17.00
MAISELS, FIONA, Dieu-DonnÈ Ekoutouba, Maximen Mboulafini, Rolland Abeguo,
Moustapha Mahmadu, and Gaby Mobolombi. Wildlife Conservation Society/ New York Zoological
Society, 2300 Southern Boulevard, Bronx, NY 10460-1099, USA, <bomassa@uuplus.com>
(FM, DDE, RA, MM, MM, GM), and Institute of Cell,
Animal and Population Biology, Kings Buildings, Edinburgh University, UK
(FM).
A FOREST LAKE IN NORTHERN REPUBLIC OF CONGO: A WINDOW ON FOREST ELEPHANT CONSERVATION
A small lake, three kilometres from a village, and twenty kilometres from Nouabale-Ndoki
National Park was heavily hunted for elephants and other animals in the 1970s and
1980s. At that time, elephants strongly avoided the village and its fields. Since
the early 1990s, an agreement between the village and the Nouabale-Ndoki conservation
project has prevented hunting and fishing at or near the lake. This agreement, plus
an effective antipoaching programme, has also stopped elephant hunting in the area.
During 2000 and 2001 we monitored large mammal use of the lake (mostly forest elephant
and forest buffalo). Observations (748 hours over 200 days) were made from a hide
two to three times weekly and animal sign on the lakeshore was recorded weekly. Twelve
different male elephants used the lake, mostly only in the mid- to late afternoon
and at night. Since 1998, several of these same individual elephants have been coming
into the village, crop-raiding, and they show no fear of humans at all. Conservation
has thus resulted in a complete change in elephant behaviour near this village, as
they perceive that it is a safe site. However, it has also resulted in a crop-raiding
problem, which the project is now trying to solve.
17.00 - 17.15
MUBALAMA, LEONARD. Monitoring Illegal Killing of Elephant (MIKE)/Wildlife Conservation
Society, C/o PNKB/GTZ, PO. Box 86, Cyangugu-Rwanda and/or PO. Box 25, 7 Cyangugu-Rwanda,
<Mikedrce@yahoo.co.uk>.
MONITORING OF LAW ENFORCEMENT AND ILLEGAL ACTIVITY IN THE OKAPIS WILDLIFE RESERVE-ITURI
FOREST, EASTERN DEMOCRATIC REPUBLIC OF CONGO
The goals of the pilot project were to design, put in place and demonstrate a process
that will permit monitoring elephants in the Ituri forest: assessing elephant distribution,
and densities and the factors that affect these, in particular illegal killing. The
specific pilot project objectives were: 1) to build capacity to monitor elephants
at local and national levels; 2) to provide data and an analysis that will permit
the pilot project to be evaluated as a model for expansion and extension of MIKE
in the sub-region and beyond. During the pilot MIKE phase, 14 locations were surveyed
from the 54 surveyed in 1994-1995. Total distance covered by linear transect 136,600
metres, 79,800 metres of recce transect and 39,700 metres of recce deplacement. Using
a dung conversion factor based on a mean defecation rate of 13 dung per day and a
mean decay rate of 55 days estimated mean elephant densities for the Ituri was 1.9
elephants/km_ (Len Thomas et al., 2001). A system of LEM, in coordination
with a bio-monitoring program, proved to be a potentially important tool to measure
the relative effectiveness of conservation investment at a given site.
17.15 - 17.30
EATON, MITCHELL, Paul Elkan, and Antoine Moukassa. Conservation Biology Program,
University of Minnesota, St. Paul, MN 55113, USA, <mje@fw.umn.edu> (ME), Wildlife
Conservation Society, Projêt de Gestion des Ecosystèmes Périphériques
du Parc, BP 14537, Mpila, Brazzaville, Republic of Congo (PE, AM).
SUBSISTENCE HARVEST MONITORING FOR WILDLIFE MANAGEMENT AND SUSTAINABILITY IN THE
REPUBLIC OF CONGO
The harvesting of wildlife is thought to be largely unsustainable in tropical forests
where human population densities have increased and hunters now use modern weapons.
The difficulty and cost of monitoring the effects of hunting on tropical vertebrate
populations requires the adoption of methods that provide indirect, reliable, and
easily collected indices of harvest sustainability. We are developing and testing
monitoring methods for a wildlife management project in forests adjacent to the Nouabalé-Ndoki
National Park, Republic of Congo. We report on the use of index methods including
harvest levels, species composition, ungulate age structure, and catch per unit effort
to evaluate the harvest over time and between sites of different hunting intensity.
The composition of harvested species-groups, catch per unit effort, and ungulate
age structure appear to be strongly correlated with hunting pressure. Directly monitoring
wildlife population densities is theoretically the most effective method to assess
the impact of hunting on vertebrates, but it is of questionable accuracy in dense
tropical forests and its costs often prohibitive. The use of indirect indices collected
from the harvest itself are more cost-effective and may provide sufficient information
for reliable wildlife management.
The SCB2002 pages are maintained by Christine Eagle
email: C.M.Eagle@ukc.ac.uk
Conference email: scb2002@ukc.ac.uk
Last updated: 30.06.02