Chapter 7: Habitat Flashcards
What is habitat degradation?
A threat to species that includes fragmentation, habitat loss, and patch isolation.
Why is the management of fragments important for species persistence?
Fragments have ecological processes such as dispersal, colonization, edge effects, and connectivity.
What is habitat heterogeneity?
Components of the habitat are diverse and numerous in type, differing between patches or as a gradient over space and time.
What is slash in the context of forest management?
Leftover debris from cut blocks in forests that provides opportunities for organisms to nest or find habitat.
What are the 3 fundamental aspects of any given habitat?
- The amount of spatial area of the habitat in relation to the size of the reference landscape
- Habitat complexity
- Habitat heterogeneity
What is the significance of connectivity between patches?
Connectivity is usually more beneficial than preservation of isolated patches.
Fill in the blank: Habitat use is different from _______.
[availability]
What does Ivlev’s Selection Index (SI) measure?
The proportion of the animal’s use of the habitat relative to its availability.
What are the four categories of habitat modification by humans?
- Intact
- Variegated
- Fragmented
- Relictual
What is the role of the matrix in habitat conservation?
The matrix can affect movement and dispersal, availability of essential resources, and the abiotic environment.
True or False: The highest levels of biodiversity are associated with sites subject to high levels of disturbance.
True
What is edge effect?
The exchange or flow of energy, material, and organisms across the boundary that alters biophysical processes and ecosystem composition.
What is the Nature Conservancy (TNC)?
One of the world’s most influential NGOs in conservation, administering the largest system of private nature reserves on six continents.
What does habitat management require due to habitats having lifespans?
We must create new habitat as well as preserve existing habitat.
What is habitat structure?
The amount, composition, and 3-dimensional arrangement of biotic/abiotic elements in an organism’s living environment.
What is succession in an ecological context?
A pattern of continuous, directional, non-seasonal change of plant populations on a site over time.
What management techniques can reset succession?
- Controlled fires
- Flooding
- Herbicides
What is habitat degradation?
The gradual deterioration of habitat quality.
What is a patch in ecological terms?
Contiguous regions of the same kind of habitat or sites where the habitat conditions of a species are realized.
What are the effects of fragmentation on species?
- Loss of specialist species
- Increased mortality in specific life history stages
- Decreased ability of some species to colonize smaller habitat patches
What is the significance of corridors in habitat fragments?
They enhance movement between fragments but results are species specific.
Fill in the blank: Habitat degradation occurs when a block of contiguous habitat is reduced in size and increasingly broken into numerous _______.
[smaller patches]
What is the effect of increased edge on interior species?
Increased edge results in less secure habitat for interior species.
What is an example of a management technique to mitigate habitat loss?
Timing limitations to schedule human activities when animals are absent.
What is the role of shape landscapes in conservation?
Serve as statistical baselines for exploring effects of spatial patterns of habitat on population persistence and growth
What organization administers the largest system of private nature reserves on six continents?
The Nature Conservancy (TNC)
What is the main aim of The Nature Conservancy in reserve planning?
To locate reserve units on a landscape to contain the largest possible number of biodiversity elements
What are the three stages of the reserve planning process?
- Many sites are screened for potential reserves
- Candidate sites are examined for their promise as part of a functional system of reserves
- Individual sites are established, managed, and monitored
What selection criteria are used for potential reserve sites?
- Ecological uniqueness
- Viability
- Threats
- Feasibility
What does ecological uniqueness refer to in reserve selection?
The site’s level of species richness, rarity, and endemism
What does viability mean in the context of reserve site selection?
Likelihood that species would persist on this site if it were protected as a reserve
What are considered threats in the context of reserve selection?
Agents that might reduce the long term viability or value of the reserve
What factors are considered under feasibility in reserve selection?
Relevant economic, sociological, and administrative factors related to the likelihood that the reserve could actually be acquired and protected
What happens if a site meets all selection criteria?
It becomes a member of a portfolio of potential sites
What is a key strategy for maximizing biodiversity in reserve selection?
Get the most species with fewest sites and get the rarest species first
What is meant by providing landscape scale population resilience?
Maximizing the likelihood of dispersal among sites
