Lecture 11 - Conserving Populations and Species

At any point in time, a population of any species can naturally be stable, increasing, decreasing, or fluctuating in number.

Applied population biology, which seeks answers to many population related questions by examining the factors affecting the abundance and distribution of rare and endangered species.

In order to effectively protect and manage a rare or endangered species, it is vital to have a firm grasp of the ecology of the species, its distinctive characteristics, and the status of its populations.

The American bald eagle received rigorous conservation action as a result of population monitoring. Breeding pairs observed at James Lake, Virginia, are shown here over time, as they relate to conservation activity. Alarmingly low numbers of nesting pairs observed across the United States in the 1960s and 1970s spurred both research and policy action, including banning the pesticide DDT (which was harming the birds through biomagnification), increasing the penalties for hunting and trapping eagles, and ________

listing for protection under the Endangered Species Act (ESA). Recovery after these actions meant that the species could be delisted, although it is still protected. The IUCN now lists them as “least concern.” It is estimated that we have as many as 14,000 nesting pairs in the lower 48 states and 30,000 in Alaska as of 2015.

Knowledge of the natural history and population biology of a species is crucial to its protection, but __________

urgent management decisions often must be made before all of this information is available, or while it is still being gathered.`

Several types of natural-history and population biology information are important to conservation biology:

Environment

Distribution

Biotic interactions

Morphology

Physiology

Demography

Behavior

Genetics

Interactions with humans

Methods for the study of populations have developed largely from the study of land plants and animals.

• Small organisms such as protists, bacteria, and fungi have not been investigated in comparable detail.

• Species that inhabit soil, freshwater, and marine habitats are particularly poorly investigated for population characteristics.

Gathering Ecological Information:

• i) Published literature

• ii) Unpublished literature

• iii) Fieldwork

Monitoring Populations:

• i) Census

• ii) Surveys

• iii) Demographic studies,

• iiii) Current and future impacts of monitoring programs

Population viability analysis (PVA) can be used to _______

predict extinction rates under different scenarios.

Hotspots are targets for protection because of their _______

high biodiversity, endemism, and significant threat of imminent extinctions.

Endangered species often require active management and intervention as part of the recovery process. There is a __________

continuum, with some species independent of humans and others dependent on human intervention.

The longer species have been listed, protected, and managed under the Endangered Species Act, the greater is their _________

probability of improving in status and the slower is their probability of continuing to decline in status