🐒Animal Behavior Unit 8 – Habitat selection and migration

Key Concepts

• Habitat selection involves an animal's choice of where to live based on various environmental factors and resources
• Migration is the seasonal movement of animals between different habitats, often driven by changes in resource availability or environmental conditions
• Natal habitat preference induction (NHPI) is the process by which an animal's early life experiences influence its future habitat preferences
• Philopatry refers to the tendency of an animal to return to its birthplace or a specific area for breeding or other purposes
• Ecological niche includes the habitat, resources, and environmental conditions that a species requires for survival and reproduction
• Habitat suitability models predict the likelihood of a species occurring in a particular habitat based on environmental variables
• Habitat fragmentation is the division of continuous habitats into smaller, isolated patches due to human activities or natural processes

Habitat Selection Basics

• Habitat selection occurs at multiple spatial scales, from microhabitats to landscapes
  • Microhabitat selection involves choosing specific features within a habitat (vegetation structure, substrate type)
  • Macrohabitat selection involves choosing among different habitat types (forests, grasslands, wetlands)
• Animals use various cues to assess habitat quality, including vegetation structure, resource availability, and presence of conspecifics or predators
• Habitat selection is a hierarchical process, with animals first selecting a general habitat type and then fine-tuning their choice based on more specific factors
• The ideal free distribution theory predicts that animals will distribute themselves among habitats in proportion to the available resources
• Habitat selection can be influenced by both innate preferences and learned experiences
• Specialist species have narrow habitat requirements and are more sensitive to habitat changes, while generalist species can thrive in a wider range of habitats

Factors Influencing Habitat Choice

• Resource availability, such as food, water, and shelter, is a primary driver of habitat selection
• Predation risk can influence habitat choice, with animals avoiding areas with high predator density or selecting habitats that provide better protection
• Competition for resources can lead to habitat partitioning, where different species or individuals use different parts of the habitat to minimize overlap
• Environmental conditions, such as temperature, humidity, and elevation, can affect habitat suitability and selection
• Social factors, such as the presence of mates or conspecifics, can influence habitat choice, particularly during breeding seasons
• Anthropogenic factors, such as habitat modification, fragmentation, or disturbance, can alter habitat selection patterns and force animals to adapt to new conditions
• Habitat edges, or boundaries between different habitat types, can be attractive to some species due to increased resource diversity or edge effects

Migration Patterns and Types

• Seasonal migration is the most common type, with animals moving between breeding and non-breeding habitats in response to changes in resource availability or environmental conditions
  • Examples include bird migration between temperate and tropical regions and ungulate migration between high-elevation summer ranges and low-elevation winter ranges
• Altitudinal migration involves movements between different elevations within a mountain range, often in response to seasonal changes in temperature or resource availability
• Partial migration occurs when only a portion of a population migrates while the rest remain resident in a single habitat
• Irruptive migration is an irregular pattern of movement in response to fluctuations in food availability or population density
• Nomadism is a less predictable form of movement where animals follow unpredictable resource patches across a landscape
• Diel vertical migration is a daily pattern of movement between different depths in aquatic environments, often in response to light levels or predation risk

Evolutionary Significance

• Habitat selection has evolved as an adaptive response to maximize fitness in heterogeneous environments
• Natural selection favors individuals that choose habitats that enhance their survival and reproductive success
• Habitat selection can lead to local adaptation, where populations become specialized to the specific conditions of their chosen habitat
• Migration has evolved as a strategy to exploit seasonal resource pulses, avoid unfavorable conditions, or reduce competition and predation risk
• The ability to navigate during migration has evolved through various mechanisms, such as celestial cues, magnetic fields, or landmark recognition
• Migratory behavior can be genetically determined or culturally transmitted through social learning
• Habitat selection and migration can influence gene flow and population structure, leading to genetic differentiation or speciation

Research Methods and Tools

• Habitat suitability models use environmental variables and species occurrence data to predict the likelihood of a species occurring in a particular habitat
• Radio telemetry involves attaching radio transmitters to animals to track their movements and habitat use
• GPS tracking provides high-resolution data on animal movements and can reveal fine-scale habitat selection patterns
• Remote sensing techniques, such as satellite imagery or aerial photography, can be used to map and characterize habitats across large spatial scales
• Stable isotope analysis can provide insights into an animal's diet and habitat use by measuring the ratios of different isotopes in their tissues
• Behavioral observations, such as focal animal sampling or scan sampling, can reveal how animals interact with their habitat and make selection decisions
• Experimental manipulations, such as habitat alteration or translocation studies, can test hypotheses about the factors influencing habitat selection

Case Studies and Examples

• Monarch butterfly migration involves a multi-generational journey between breeding grounds in North America and overwintering sites in Mexico, with individuals using a combination of celestial and magnetic cues for navigation
• Salmon undergo a remarkable migration from freshwater streams to the ocean and back again, using olfactory cues to return to their natal streams for spawning
• African elephants exhibit seasonal migration patterns in response to rainfall and vegetation dynamics, with some populations traveling hundreds of kilometers between wet and dry season ranges
• Migratory birds, such as Arctic terns, make incredible journeys between the Arctic and Antarctic regions, covering tens of thousands of kilometers each year
• Habitat selection in grizzly bears is influenced by factors such as food availability, human disturbance, and denning requirements, with individuals selecting different habitats depending on the season and their reproductive status
• Coral reef fish exhibit microhabitat selection based on factors such as coral cover, reef complexity, and predation risk, with many species using specific coral species or morphologies for shelter

Ecological Implications

• Habitat selection and migration can influence species interactions, such as predator-prey dynamics or competition, by altering the spatial and temporal overlap between species
• Changes in habitat availability or quality due to human activities or climate change can disrupt habitat selection patterns and lead to population declines or shifts in species distributions
• Migratory species play important roles in ecosystem functioning by transferring nutrients and energy between different habitats and regions
• Habitat connectivity is crucial for maintaining migratory routes and facilitating gene flow between populations
• Conservation strategies for migratory species often require international cooperation and protection of critical habitats across their entire range
• Understanding habitat selection and migration patterns can inform management decisions, such as habitat restoration, corridor design, or the timing of human activities to minimize disturbance
• Habitat selection and migration can have cascading effects on ecosystem processes, such as nutrient cycling, seed dispersal, or trophic interactions