BIO3082 Lecture Notes - Lecture 8: Arctic Fox, Ecological Niche, Phenology
Lecture 8 – Range Shifts and Phenology
Relationships between Ecological Niches and Species Distributions
• Population can only exist in tolerable environments and within an organism’s
niche: the set of conditions and resources in which they can grow and survive
o Climatic factors: temperature and moisture, define niches of a species
• Fundamental niche
o Set of environmental conditions that a
population can theoretically grow in
• Realised niche
o The environmental conditions in which a
population actually occupies, e.g. due to
restrictions caused by interspecies competition
• Tolerance niche
o A environment a population can theoretically
persist in
Environmental Niche Modelling
• Estimates the niches of organisms by integrating data on their current
geographical distribution with mapped climatic variables
• Can use this information to predict the future geographical distribution of
species according to different climate forecasts
• Limitations
o Mass predictions
o Prey interactions
o Adaptations
o Based on assumption that organism cant evolve
How Climate Change may Affect Species Ranges and Timings
• Climate change means environments where populations are currently
distributed are changing
• Some of these environments may become incompatible with a species’
fundamental niche
• Global warming: fundamental → tolerance niche (conditions where population
can survive but can’t grow)
o Current distribution from fundamental → outside specie’s entire niche
after warming: extinction
If Species are faced outside their niche: To Ways for Populations to Change
Distribution (Adapt)
• Changes in Space
o Geographical range of populations may shift over time as a species
tracks suitable climates
o Due to both range expansions and contractions at given locations
• Changes in Time
o Timing of processes such as animal migrations or plant budding may
change to reflect climatic conditions
o Processes: phonological changes and reflect phenotypic plasticity
Examples of Range Shifts and Phenology Changes
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