Wildlife Biology - 2024 - Ellison - Social interactions and habitat structure in understanding the dynamic space use of

Title: Untangling the Abiotic and Biotic Feedback Mechanisms Driving Animal Movements and Ranges

Introduction

  • Understanding Movements: Core question in ecology is understanding how abiotic (non-living) and biotic (living) factors influence animal movements.

  • Importance of Modeling: Recent developments in process-based modeling improve insights into movement drivers and spatial patterns of animals.

  • Case Study: The study focuses on wild pigs (Sus scrofa), examining their movement in relation to social interactions and land cover types in agricultural landscapes.

  • Key Findings: Social interactions are more influential than land cover selection in determining movement choices.

Research Significance

  • Evidence for Management Decisions: Insights help guide sustainable management of natural resources.

  • Complex Patterns of Space Use: Animal movements involve a complex interplay of factors including spatio-temporal processes.

Modeling Approaches

Two Categories of Modeling

  • Correlative Models: Analyze the correlation between animal locations and environmental layers to understand habitat preferences (e.g., resource-selection analysis).

  • Process-based Models: Use differential equations to model animal movement dynamics rather than simplistic correlation.

Step-Selection Analysis (SSA)

  • Definition: SSA is a common method to investigate habitat selection while accounting for movement capabilities and dynamics.

  • Advancement Over Traditional Methods: SSA can reflect more complex behavioral dynamics influencing animal space use.

Study Methods

Data Collection

  • Capture: 16 adult wild pigs were fitted with GPS collars for tracking movements every 2 hours.

  • Study Area: Research conducted in Mississippi Alluvial Valley, a region characterized by significant agricultural activity.

  • Focus Duration: Data analyzed from April 5, 2016, to June 3, 2016, including interactions among 12 selected individuals.

Movement Analysis

  • Hypothesis: Movement decisions influenced by the spatial configuration of land cover and interactions among conspecifics.

  • Model Framework: Combinatorial modeling approaches assess habitat selection alongside social interactions using lasso regression for variable selection.

Results

Habitat Preferences

  • Environmental Selection: Wild pigs were found selecting corn, cotton, and woodland while avoiding rice and soybean fields. Selection indicates preference for certain habitat types and avoidance of less favorable conditions.

  • Quadratic Responses: Analysis revealed pigs also select habitats based on intermediate resource abundance rather than simply maximizing resource availability.

Social Interaction Dynamics

  • Influence on Movement: Many pigs showed attraction to areas used by other pigs while simultaneously avoiding areas that were overused.

  • Implications for Management: Knowledge of the social structure and interactions in wild pig populations aids in predicting spread and behavior of these invasive species.

Discussion

Key Insights

  • Social Dynamics vs Environment: Findings suggest social interactions significantly shape wild pigs' movements, often outweighing environmental selectivity.

  • Overuse Avoidance: Pigs adopt avoidance strategies in densely used regions by other pigs, illustrating the complexity of social structures influencing resource use.

  • Implications for Disease Management: Understanding social dynamics helps mitigate potential disease transmission due to cohesive social behaviors in pig populations.

Conclusion

  • Models of Dynamics: Effective modeling should incorporate both social and environmental factors to derive clearer insights into animal movement and space use.

  • Future Directions: Exploring hierarchical patterns of movement and their relation to habitat selection enhances understanding of ecological influence and management practices.