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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 Risk Assessment and Uncertainty
Monday 15th July, 15.30 - 17.30, Rutherford
Lecture Theatre 1
Chair: Simon Thirgood
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timetable
(BLOCK CAPITALS indicate the presenting author)
15.30 - 15.45
Cowlishaw, Guy and NICK ISAAC. Institute of Zoology, Zoological Society of London,
Regent’s Park, London NW1 4RY, UK, nick.isaac@ioz.ac.uk
(GC, NI).
DETERMINANTS OF SPECIES RESPONSES TO THREAT PROCESSES: INTEGRATING INTRINSIC AND
EXTRINSIC FACTORS
Species responses to declining-population processes can be extremely variable, yet
the factors that determine such variability remain poorly known. We explore the importance
of both intrinsic (biological) and extrinsic (anthropogenic) factors in determining
local patterns of threat response in primate species across the tropics. Our analyses
suggest that it is possible to identify biological traits that consistently correlate
with local species response, but that the specific biological traits involved are
dependent on the type of threat. This indicates that our ability to predict species
responses to future threats will be greatly enhanced by understanding the specific
mechanisms through which their effects are mediated.
15.45 - 16.00
BATIE, SANDRA S. and David E. Ervin. Department of Agricultural Economics Michigan
State University East Lansing, MI, USA, <batie@msu.edu> (SB), Environmental
Sciences and Resource Program, Portland State University and Winrock International,
Portland, OR, USA (DE).
THE ECONOMICS OF PRECAUTION: TRANSGENIC CROPS AND THE ENVIRONMENT
The uncertainty with respect to environmental impacts poses challenges for the assessment
of transgenic crops since many risks are unknown. In this sense, transgenic crops
are similar to conservation biology issues of exotic species, species extinction,
and global warming. Standard risk-benefit approaches, while embedded in U.S. regulation
of transgenic crops, appear to be an inadequate method of assessing unknown risks.
There is a need for a more fully developed "economics of precaution" that
addresses potential errors in decision-making. Two possible methods to address unknown
risks are the precautionary principle and the safe minimum standard approach. Contrary
to some statements, the precautionary principle is not unscientific. Rather it minimises
Type II risk. However, the concept seems to lack methodological sharpness. A variant
of the precautionary principle - the safe minimum standard - does provide a clear
and cautionary, but less conservative, method of analysis of these environmental
risks. A body of research on the economics of precaution in managing unknown environmental
risks can help inform and shape the research and regulation paths taken, but will
require innovative approaches to analyse uncertainty, irreversibility, option values,
and intergenerational issues that complicate many conservation biology management
decisions.
16.00 - 16.15
WOOD, CHRIS C. Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo,
B.C. Canada V9R 5K6 (woodc@dfo-mpo.gc.ca)
PRIORITIZATION CRITERIA FOR AQUATIC SPECIES AT RISK IN CANADA
Canada has developed a systematic approach to prioritize recovery activities for
aquatic species at risk based on risk management principles that consider both the
probability of losing a species and the severity of that loss. Probability of extirpation
from Canada is scored by criteria (1) COSEWIC Status and (2) Projected
Level of Threat. Severity of loss in Canada is assessed as a weighted average
value from two perspectives -- intrinsic value scored by criteria (3) Taxonomic
Level, (4) Extent of Occurrence in Canada, and (5) Global Conservation
Status, and utilitarian value scored by criteria (6) Special Significance
to Aboriginal Culture, (7) Economic Value, and (8) Social Value.
Overall severity multiplied by probability of loss yields the "expected value
of loss in Canada". Risk aversion, where unlikely incidents that would result
in severe loss are perceived as riskier than more probable but less severe incidents,
is accommodated by adjusting an exponent parameter. The weighting of intrinsic and
utilitarian values and choice of risk aversion parameter require value judgements,
but these are applied consistently across all taxa. The final risk index is used
to rank species for conservation priority with higher ranking species deserving first
consideration for conservation action at the national level.
16.15 - 16.30
THIRGOOD, SIMON, Kate Graham and Steve Redpath. Centre for Conservation Science,
University of Stirling, Stirling, FK9 4LA, UK, <s.j.thirgood@stir.ac.uk> (ST,
KG), Centre for Ecology and Hydrology, Banchory, Aberdeenshire, AB31 4BW, UK (SR).
RAPTORS AND GROUSE: CONSERVATION SCIENCE OR REALPOLITIK?
The conflict between the management of red grouse for commercial hunting in the UK
and the conservation of endangered raptors that kill grouse is a classic example
of the problems caused by the recovery of predator populations in human-dominated
landscapes. Here we present ten years of research in Scotland that has: 1) quantified
the numerical and functional response of moorland raptors to their prey and examined
the circumstances in which raptor predation can limit grouse populations and reduce
hunting bags; 2) tested alternative methods of reducing conflicts between raptor
conservation and grouse management through habitat management, diversionary feeding
and raptor translocation; and 3) developed a novel risk assessment approach to evaluating
the potential efficacy of different management prescriptions. Finally we 4) make
a realistic assessment of whether this program of monitoring, experiments and modelling
has improved either the conservation status of moorland raptors or increased the
commercial returns from harvesting red grouse. We conclude that management decisions
from either side of the conservationist/hunter divide are driven more by realpolitik
than conservation science.
16.30 - 16.45
HEDGES, SIMON and Martin J. Tyson. Wildlife Conservation Society — Indonesia
Program, P.O. Box 311, Bogor 16003, Indonesia, <simonhedges@freenet.co.uk>
(SH, MT), Wildlife Conservation Research Unit, Department of Zoology, Oxford University,
UK (SH, MT), Department of Biology, Southampton University, UK (SH, MT).
CONFLICT BETWEEN ENDANGERED SPECIES, EXTINCTION RISK, AND THE AGONY OF CHOICE: DHOLES
AND BANTENG IN JAVA
Banteng, Bos javanicus, are an endangered bovid species whose global population
is thought to number 5000—8000 animals. Alas Purwo National Park in Java, Indonesia,
formerly contained 300—400 banteng, probably the world’s largest banteng population.
This population, along with that in the nearby Baluran National Park, was studied
from 1991 to 1999. In 1993, park staff speculated that the Alas Purwo banteng population
was in decline as a result of predation by dholes, Cuon alpinus, also an endangered
species. Population size, age- and sex-ratio data, as well as mortality rates for
1993—1997 are presented to show that the banteng population was rapidly declining,
and that the dholes were largely responsible. Simulation models using these data
indicated that without intervention the banteng population would decline to effective
extinction by 1998/99, and the dholes would be threatened by the collapse of their
prey base. Subsequent monitoring supported these conclusions: by January 1999 only
17 adult female banteng were known to exist in Alas Purwo and no recruitment had
occurred for six years, the dholes had also apparently disappeared. The difficulties
of resolving such conflicts between endangered species are discussed, as are the
options that were available to the park's managers.
16.45 - 17.00
ZULKA, KLAUS PETER, Erich Eder, Helmut Höttinger and Erich Weigand.
Federal Environment Agency, Spittelauer Lände 5, A-1090 Vienna, Austria, <zulka@ubavie.gv.at>
(KPZ), Institute of Zoology, University of Vienna, Althanstr. 14, A-1090 Vienna,
Austria (EE), University of Agriculture, Institute of Zoology, Gregor-Mendel-Str.
33, A-1180 Vienna, Austria (HH) and National Park Kalkalpen, Nationalparkallee 1,
A-4591 Molln, Austria (EW).
EXTINCTION THREAT ASSESSMENT ON A NATIONAL SCALE — THE AUSTRIAN RED LIST CONCEPT
Red Lists of threatened organisms are well-established tools for species conservation
and environmental control. However, vagueness of threat criteria and inconsistencies
in their application had stimulated a critical discussion on assessment methodology,
which produced a new IUCN criteria system for the world lists of threatened species.
In the light of this progress, the Federal Environment Agency in Vienna has developed
a concept for national threat assessment, which is intended to improve consistency,
repeatability, objectivity and documentation of future Austrian red lists. Data of
different types and quality can be incorporated into the assessment process. With
these data, several threat indicator scales (e.g. abundance trends, habitat availability)
are calibrated for each animal group to be listed. Then, threat descriptor value
combinations are linked to threat categories by means of a dichotomous key. Threat
categories are uniformly defined in terms of extinction probability per unit time.
The final list displays threat category, threat descriptor values, national responsibility,
action priority and a reference to a comment field for any additional information
on threat factors, reasoning and data quality. Under particular scale calibrations,
the IUCN criteria appear as a special case in the proposed system.
17.00 - 17.15
REGAN, TRACEY J., Mark A. Burgman, Michael A. McCarthy and Sandy J. Andelman.
School of Botany, University of Melbourne, Parkville, VIC 3010, Australia, <t.regan@pgrad.unimelb.edu.au>
(TJR, MAB, MAM), National Center for Ecological Analysis and Synthesis, University
of California Santa Barbara, 735 State St., Suite 300, Santa Barbara, CA 93101, USA
(SJA).
THREATENED SPECIES CLASSIFICATIONS AND POPULATION VIABILITY ANALYSIS: SHALL EVER
THE TWAIN MEET?
Threatened species classification protocols use surrogates such as range size, abundance
and declines to estimate the level of threat of extinction faced by species. Population
viability analysis is a quantitative method for estimating the probability of a species
declining to extinction or to some population threshold by using all available information
pertaining to the species population dynamics. Both methods aim to determine the
risk of extinction of species but are often used in isolation of one another. The
IUCN protocol has criteria to incorporate quantitative estimates of extinction risk,
but this criterion has never been used alone to determine a species’ status. Using
the classification protocols employed by the IUCN, The Nature Conservancy, and the
Florida Game and Fresh Water Fish Commission, we compare the relative ranks of a
set of species with the relative ranks of the same species based on projections from
stochastic population models. The comparison elucidates the mechanisms influencing
the outcomes of both the classification protocols and PVA models, and highlights
the fundamental differences between the two approaches.
17.15 - 17.30
SHARMA, RISHI, Scott Raborn and David Bernard. Columbia River Intertribal Fish
Commission, Suite 200, 729 NE Oregon St, Portland, OR 97232, USA, <shar@critfc.org>
(RS), Department of Biology, Northwestern State University, Natchitoches, LA 71497,
USA (SR) and Alaska Department of Fish and Game, 333 Raspberry Rd, Anchorage, AK
99518, USA (DB).
ESTIMATING CRITICAL THRESHOLDS IN POPULATIONS: A SIMULATION BASED APPROACH
The last decade has pointed out the flaws with point estimates for sustainable management
of harvested populations. We incorporate the Sample Importance Re-sampling (SIR)
algorithm to exhibit the uncertainty in point estimates generated by models for management
of salmon and waterfowl. Using current knowledge of a particular population’s dynamics,
we present a method that shows how drastic perturbations of different durations can
affect the population trajectories for different species. Based on comparisons between
population dynamics created by unforeseen perturbations on the population of concern,
and baseline conditions of equilibrium (no perturbation) for the particular population,
we estimate critical limits for population resiliency. If we assume that the population’s
dynamics are representative of the species in a given area, we can present probabilistic
statements of going below these critical thresholds. Given current understanding
of the population’s dynamics, we can thus assess the risk to the particular population
group as a whole.
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