Species distribution

Species Distribution

• Range
• A species range map shows where individuals can be found.
• The range is the geographical area a species inhabits.
• Various terms describe different aspects of a species’ range, such as natural range, non-native range, summer range, and breeding range.
• Disjunct distribution occurs when parts of a species’ range are far apart.
• Factors like latitudinal range and elevational range describe geographic ranges.

• Factors Affecting Species Distribution
• Abiotic Factors
• Include climatic factors, edaphic factors related to soil, and social factors like land use.
• Influence species distribution by affecting resource availability.
• For instance, species in drier areas tend to concentrate around water sources.
• Rising ocean temperatures due to climate change are causing species to shift their ranges.
• Human activities, including global transportation, impact species distribution.
• Biotic Factors
• Predation, disease, and competition influence species distribution.
• Clumped distribution can help populations detect predators early and defend themselves.
• Limited resources can lead to even distribution patterns to minimize competition.
• Human activities, like ballast water discharge from ships, can introduce species to new areas.

Distribution Patterns

• Large-Scale Patterns
• Distribution patterns are often clumped within populations on a large scale.
• Influenced by factors like resource availability and habitat structure.
• Human activities can disrupt large-scale distribution patterns.
• Conservation efforts aim to protect these patterns.

• Bird Wildlife Corridors
• Bird species exhibit specific range patterns along water bodies like rivers and oceans.
• Examples include river corridors and mountain range corridors.
• Migration patterns vary based on range connections.
• Conservation of bird wildlife corridors is crucial for biodiversity.

• Distribution Types
• Clumped Distribution
• Common where predator detection is easier.
• Seen in species with offspring dependent on habitat.
• Examples include African wild dogs’ communal hunting.
• Regular or Uniform Distribution
• Less common, seen in species like penguins with territorial behavior.
• Examples include plants like creosote bushes.
• Random Distribution
• Least common, occurring in consistent environmental conditions.
• Examples include dandelion seed dispersal.

Statistical Analysis and Models

• Statistical Determination of Distribution Patterns
• Methods include Clark-Evans nearest neighbor method and variance/mean ratio method.
• Analysis involves comparing observed data with expected random distribution.
• Importance of ecological models in species distribution models.

• Species Distribution Models
• Predict distribution based on spatial biodiversity patterns.
• Include disturbance, dispersal, and population dynamics in hierarchical models.
• Assess climate change impacts and conservation management issues.

Species Distribution Grids

• Project Details
• Led by the University of Columbia to map animal species distributions.
• Focus on preventing deforestation and prioritizing areas based on species richness.
• Data available for global amphibians, birds, and mammals in the Americas.
• Includes representative samples of available data for download.

Species distribution Data Sources