Ch12 Student Presentation

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Transcript Ch12 Student Presentation

Key to protecting and managing a rare and endangered species depends on the
This type of information can be obtained by doing the following:
1) Examine the unpublished and published literature
2) Fieldwork to monitor populations and ecosystem conditions
-only in the field can conservation status be determined
Ex. Magellanic penquins were fitted with radio collars and found to
forage 600 km from nest. Argentine government extended time for a
fishing exclusion zone until chicks mature and population grew
Figure 12.1, 12.2
Monitoring over many years can lead to extensive knowledge that can be
used in conservation of rare species. Box 12.2
12.1 Magellanic penguins incubating eggs forage up to 600 km from their breeding colonies
12.2 Monitoring populations requires specialized techniques suited to each species
Box 12.2 “Trimates” Dian Fossey (left), Jane Goodall (center), and Birute Galdikas
3) carry out a census
-count the number of individuals present in a population
Ex. Hawaiian monk seal census (Figure 12.3) and British Isles woodland
cudweed (Figure 12.4)
4) carry out surveys
-use of a repeatable sampling method to establish the number of
individuals of a species in a community
ex mark/recapture surveys for birds and mammals and quadrat sampling
-using environmental DNA (eDNA) isolated from samples of lake, pond,
or stream water can indicate the presence of endangered or invasive
species that may live there. Rates of detection have been better in
ponds than in streams Read Box 12.1 and Figure from Thompson
et al. (2012)
12.3 A census of Hawaiian monk seals determined they were endangered
12.4 The British Isles Monitoring Scheme for Gnaphalium sylvaticum, the woodland cudweed
Box 12.1 Finding a needle in a haystack: Monitoring rare species with environmental DNA (eDNA)
Box 12.1 Finding a needle in a haystack: Monitoring rare species with environmental dna (eDNA)
12.5 Killer whale monitoring shows an increase in Hudson Bay=seals & other prey will decline
5) carry out demographic studies and monitoring
-follow individuals in a population to determine rates of growth,
reproduction and survival Fig. 12.5
Population viability analysis (PVA)
• Extension of demographic analysis using risk assessment much like
life insurance mortality tables
• Various mathematical and statistical methods are used to predictthe
probability that a population will go extinct, change in size, or change
in area occupied.
Examples of PVA
• Hawaiian stilt is an endangered, endemic bird that has been reduced to
a population of 200 individuals because of hunting and coastal
development. Protection has allowed the population to increase to
1600 with a goal of 2000. A PVA of mortality rates indicated the need
for control of exotic predators as well as wetland protection and
• Marsh Fritillary butterfly in the United Kingdom occupies lightly
grazed grasslands. Of the six populations left, PVA indicated that only
two had enough area to persist for 100 years Figure 12.7
• Leadbetters possum is an endangered arboreal marsupial and a PVA
about 30 years ago predicted declines of more than 90% if forest
patches with cavities used for dens were not protected. Logging and
severe wildfires have currently reduced the population by 80%
Figure 12.7 Population viability analyses predict that it takes 100 ha of habitat to ensure the persistence of a marsh fritillary butterfly population
for 100 years
Figure 12.7 Population viability analyses predict that it takes 100 ha of habitat to ensure the
persistence of a marsh fritillary butterfly population for 100 years
Over time, populations of a species may become extinct on a local scale,
while new populations may form nearby on suitable sites. These
species or those of ephermal habitats are referred to as
-a metapopulation is an aggregate of temporary or fluctuating smaller
populations linked by migration
-the metapopulation concept recognizes that local populations are dynamic
and have several possible patterns Figure 12.8
-metapopulation concept has proved to be more useful in understanding
and managing species than a single population approach
Ex. California mountain sheep, Figure 12.9, need migration routes
between known population areas protected
Ex. The endemic Furbish’s lousewort occurs along a 200km. stretch of St.
John’s River in Maine and New Brunswick subject to flooding.
Flooding destroys populations but forms exposed riverbank in other
areas that are recolonized by the plant. Again, instead of managing
populations, the watershed’s metapopulation is managed Figure 12.10
12.8 Possible metapopulation patterns, with size of a population indicated by the size of the circle
12.9 Mountain sheep range, population, and migrations in 1990
12.10 Furbish’s lousewort populations are best protected as a metapopulation
The Long-Term Ecological Research (LTER) program
Long-term monitoring projects have been facilitated by the establishment
of 172 Long-term Ecological Research Sites (LTER) established by
the National Science Foundation (NSF) Figure 12.11
-with long-term data, one can make better management decisions
Ex. salamander species thought to be rare on the basis of several years of
low breeding numbers turned out to be common in a favorable year
Ex. 40 years of observation in flamingoes in southern Africa revealed that
large numbers of chicks fledged mostly in years with high rainfall
Figure 12.12
12.11 The Long-Term Ecological Research (LTER) program
12.12 Rainfall data (bars) from Etosha National Park for years 1956 to 2004. Circles are chick data (caption)