Landscape Ecology Notes

Landscape View of Population Dynamics

• Patches can vary in space and time, affecting habitat quality.
  • Small-scale differences within patches (e.g., nesting sites).
  • Variation in quality among patches influences local populations.

Habitat Tracking

• Organisms track changes in habitat quality for survival.
  • Species migrate to track seasonal changes.
  • Movements from unsuitable to suitable habitats with predictable patterns.

Landscape Connectivity

• The matrix isn't homogeneous; it influences movement.
  • Landscape connectivity: how connected the landscape is via the matrix.

Habitat Heterogeneity and Extinction Risk

• More heterogeneous environments lead to less variable populations.
  • $\text{Habitat heterogeneity} \downarrow \rightarrow \text{Extinction risk} \uparrow$, especially with small patch areas

Habitat Tracking and Environmental Changes

• Habitat tracking driven by predictable environmental changes.
  • Temporal transitions from suitable to unsuitable habitats.
  • Species persist by tracking suitable habitat patches.

Connectivity Among Patches

• Movement patterns depend on encountered environments in the matrix.
  • Dispersal kernels vary based on matrix habitat type.
  • Example: butterflies in forests vs. meadows.

Patch Edge Effects

• Transitions between habitats influence organism behavior.
  • Butterflies prefer to be near forest edges but not right against them, to mediate predation risk.

Patch Context Matters

• Landscape ecology breaks matrix into different environments.
  • Matrix heterogeneity influences individual movement.

Matrix Influence Example

• Butterfly movement varies with vegetation type (meadow, willow, conifer).
  • Equation: $m = \frac{c}{d<em>m + r</em>w d<em>w + r</em>c d_c}$, where:
    • m = number of migrants
    • $d_m$ = path distance through meadow
    • $d_w$ = distance through willow
    • $d_c$ = distance through conifer
    • $r_w$ = resistance of willow
    • $r_c$ = resistance of conifer

Butterfly Species and Habitat Preference

• Different butterfly species show varying resistance to habitat types.
  • Short-winged species prefer meadow.
  • Agile species move through all habitat types equally.

Metapopulation vs. Landscape Ecology

• Metapopulation ecology: patches in a uniform, inhospitable matrix.
• Landscape ecology: spatial arrangement of different habitats within the matrix.

Patch Mosaic Approach

• Hybrid approach combining metapopulation and landscape ecology.
  • Incorporates matrix heterogeneity to describe organism movement.

Choosing a Landscape Ecology Approach

• Use when the matrix isn't featureless and patches are scarce.
• Useful when habitat patterns are stable with defined migration routes.
• Apply when organisms move over manageable scales, and matrix nature influences movement.