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Realised rather than fundamental thermal niches predict site occupancy: Implications for climate change forecasting
Author(s) -
Braschler Brigitte,
Duffy Grant A.,
Nortje Erika,
KritzingerKlopper Suzaan,
Plessis Dorette,
Karenyi Natasha,
Leihy Rachel I.,
Chown Steven L.
Publication year - 2020
Publication title -
journal of animal ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.134
H-Index - 157
eISSN - 1365-2656
pISSN - 0021-8790
DOI - 10.1111/1365-2656.13358
Subject(s) - ectotherm , occupancy , ecological niche , niche , foraging , ecology , climate change , abundance (ecology) , microclimate , relative species abundance , range (aeronautics) , species distribution , global warming , environmental science , biology , habitat , materials science , composite material
Thermal performance traits are regularly used to make forecasts of the responses of ectotherms to anthropogenic environmental change, but such forecasts do not always differentiate between fundamental and realised thermal niches. Here we determine the relative extents to which variation in the fundamental and realised thermal niches accounts for current variation in species abundance and occupancy and assess the effects of niche‐choice on future‐climate response estimations. We investigated microclimate and macroclimate temperatures alongside abundance, occupancy, critical thermal limits and foraging activity of 52 ant species (accounting for >95% individuals collected) from a regional assemblage from across the Western Cape Province, South Africa, between 2003 and 2014. Capability of a species to occupy sites experiencing the most extreme temperatures, coupled with breadth of realised niche, explained most deviance in occupancy (up to 75%), while foraging temperature range and body mass explained up to 50.5% of observed variation in mean species abundance. When realised niches are used to forecast responses to climate change, large positive and negative effects among species are predicted under future conditions, in contrast to the forecasts of minimal impacts on all species that are indicated by fundamental niche predictions.