Towards Sustainable Population Management - Waza

WAZA magazine Vol 12/2011
Sarah Long 1 *, Candice Dorsey 2 & Paul Boyle 2
Status of Association of Zoos
and Aquariums Cooperatively
Managed Populations
Introduction
The Association of Zoos and Aquariums
(AZA) is one of the many zoo
associations worldwide that is
undergoing a renewed focus on the
sustainability of its managed populations.
Sustainability is generally
characterised by population biologists
as the ability of a population to
maintain a stable size and healthy
age structure through reproduction
(if self-sustaining) or other means
(importation from private facilities,
other regions or the wild). Genetic
diversity is often measured as a component
of population viability, as
genetically diverse populations are
likely to be more resilient in adapting
to environmental change and avoiding
the negative effects of inbreeding
depression (Frankham et al. 2002).
Maintaining both demographic
stability and gene diversity have long
been part of cooperatively managed
programmes in zoos and aquariums,
including AZA’s Species Survival Plan®
(SSP) and Population Management
Plan (PMP) programmes. Here, we
present an examination of the current
demographic and genetic status of
AZA cooperatively managed Animal
Programmes and an assessment of
key indicators of the viability of these
populations.
1 Population Management Center,
Lincoln Park Zoo, Chicago, IL, USA
2 Association of Zoos and Aquariums,
Silver Spring, MD, USA
* E-mail for correspondence:
slong@lpzoo.org
As in other regions, population management
in AZA depends upon a network
of volunteer studbook keepers
and species coordinators to collect,
compile and validate pedigrees and
life histories (birth/hatch dates and
locations, transfer events, death
dates and locations) for each individual
of a cooperatively managed population
and to coordinate animal and
institutional needs with population
goals. AZA is unique among regional
zoo associations in having a staff of
full-time professional population
biologists assisting its cooperatively
managed programmes. The AZA Population
Management Center (PMC)
based at Lincoln Park Zoo in Chicago,
IL provides a bridge between studbook
data and the management plan
by helping to improve data quality,
conducting demographic and genetic
analyses and integrating institutional
needs and husbandry information
into breeding and transfer recommendations.
The transformation of
studbook data into management
plans is an essential step in population
management, without which cooperative
efforts towards population
stability and genetic management
are likely to falter. Since its inception
in 2000, the PMC has provided
scientific and logistical support to
approximately 60% of AZA’s Animal
Programmes, producing more than
800 management plans for over 300
populations. Some of the remaining
populations are assisted by a small
number of volunteer advisors, but
over 150 AZA Animal Programmes
have yet to receive any formal population
management advice because
they are newly designated, awaiting
assistance from a population biologist,
or lack a studbook database or
a species coordinator.
Despite all the organisational, institutional
and scientific resources
dedicated to these cooperatively
managed programmes, AZA populations
are facing challenges similar
to zoo populations in other regions –
limited space for expansion, loss of
gene diversity, declining population
sizes, incomplete data with which
to manage the populations – all of
which may threaten the ability of
AZA-accredited zoos to meet their
exhibit, education or conservation
goals with these species. In an attempt
to characterise the viability
of AZA-managed populations, basic
descriptive information was gathered
from studbooks and management
plans for 428 populations and results
of demographic and genetic analyses
conducted by the PMC have been
summarised for 319 populations. Of
particular interest are measures that
provide insight into genetic and demographic
health, such as founding
population size, current population
size, proportion of animals breeding
and recent population growth rates.
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