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This chapter explores the definition and significance of habitat, including its role in species abundance and distribution, population dynamics, natural resource management, and ecological restoration. It also discusses the challenges in standardizing habitat terminology and the constraints on resource use. The concept of habitat management is introduced, along with different types of management approaches. An example of habitat management in a forest ecosystem is provided, highlighting the benefits of dead trees and down woody material for wildlife.
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Chapter 6 What is wildlife?
Traditional Definition • •Game animals.
Modern Definition • •Terrestrial vertebrates
Significance • •Fundamental ecological paradigm. • •Species abundance & distribution. • •Population dynamics.
Significance • •Natural resource management. • •Assessing human impacts. • •Predicting landscape-level changes. • •Ecological restoration. • •Species recovery. • •Species inventory.
No standard terminology • •82% of studies use the term “habitat” incorrectly (Hall et al. 1997).
Why bother with standard terms? • •Fundamental concepts should be well defined. • •Enhances communication.
Habitat • •The biotic and abiotic resources in an area that allow for the survival and reproduction of a given organism, i.e. fitness • –Habitat is organism-specific. • –Habitat is not vegetation type
•Habitat involves a functional relationship between resources and animal fitness • fitness = resource1 + resource2 + resource3
Habitat Use • •The way an animal uses or consumes resources in a habitat.
Constraints on Resource Use • •Predation • •Competition • •Parasites • •Disease • •Human impacts
Habitat Selection • •The process by which an animal chooses which resources to use. • •Habitat preferenceis the outcome of this process
Habitat Availability • •The accessibility of resources. • •Availability ≠Abundance.
Habitat Quality • •The relation between resources and population persistence. • •A habitat is high-quality if it contains all the resources necessary for population persistence. • •Quality is a function of demographic parameters, e.g. survival, reproduction
What is habitat management? • Depends on the objective • •Harvest • •Endangered species recovery • •Biodiversity conservation
Types of Management • •Manipulation • •Preservation • •Restoration
Example of habitat • Dead trees or snags provide a valuable forest component for wildlife which use these standing habitats as a place to feed, nest, perch and roost. Some birds which inhabit tree cavities feed on insects, which left uncontrolled, can cause damage to commercial crop trees. As cavity trees decay, they eventually fall and become large woody material on the forest floor, providing additional benefits for wildlife as well as improving soil productivity.
Some small mammals, birds and amphibians use large, down woody material as a place to live and feed on insects, seeds and fungi found on the forest floor. Forest managers know that if soil fungi is eliminated from the forest system, tree seedlings have difficulty becoming established because they cannot successfully extract nutrients and minerals from the soil. Small mammals feed on fungi and pass fungal spores in their droppings. As the animals move about the forest they dispense spores and insure that the invaluable fungi will remain available throughout forest succession
As large woody material decays over time it continues to provide benefits for a woodlot and the ecosystem. Decaying wood acts as a reservoir for water storage by slowly releasing moisture throughout the summer. This helps maintain a moist, cool forest floor where seedlings can survive. Phosphorus, potassium and other nutrients are released providing essential elements for the growth of trees.
Nitrogen fixing bacteria live in decaying wood and produce nitrogen, an essential nutrient for forest tree growth. Eventually, over a period of years, the decaying woody material becomes part of the soil, contributing to the cycle of forest health.
West of the Cascades in Oregon and Washington, 39 species of birds and 14 species of mammals depend on cavity trees for their survival. East of the Cascades 39 bird species and 23 mammal species depend on these trees. Additionally, many species of fungi, moss, lichens, ferns, invertebrates, reptiles and amphibians that form an integral part of a healthy forest also depend on dead trees and down woody material for all or a part of their life cycle.