Are fundamental niches larger than the realized? Testing a 50-year-old prediction by Hutchinson

Abstract

For more than 50 years ecological niches have been defined as combinations of multidimensional environmental conditions permitting a species to survive and reproduce. A fundamental niche (NF) is defined as the set of conditions within which a species can live in the absence of competitors, and a realized niche (NR) is a NF hypothetically reduced by competitive interactions (and some other limiting factors). This definition implies that NF is “larger” than NR, something that has been nearly universally accepted by ecologists. However, there have been few attempts at empirical tests. Here, we present a novel quantitative test using one-dimensional estimates of NF for 105 species of reptiles and amphibians, and estimates of NR obtained from ~1.4 x 104 field observations. To specify our test, we operationalize the original classification of niche types. Our results predominantly support the hypothesis that NF ‘is larger’ than NR and we highlight the theoretical and practical importance of quantifying niches.

Projecting the Range Shifts in Climatically Suitable Habitat for Chinese Sea Buckthorn under Climate Change Scenarios

“…This is smaller than the fundamental niche, which is related to species physiological limits [39]. Booth et al [5,40] believe that under climate change long-lived trees, already well-established at a particular site, may be able to show some of the climatic adaptability that they show in trials outside of their natural distributions.…”

A macroecological approach to evolutionary rescue and adaptation to climate change

“…The potential impacts of short‐term human‐induced climate change on biodiversity have been extensively evaluated (Parmesan and Yohe , Parmesan , Bellard et al , Garcia et al , Pecl et al ). This research program found widespread evidence that phenology and demography of species are correlated with different dimensions of climate, with varying strength across geographical and environmental gradients.…”

“…This research program found widespread evidence that phenology and demography of species are correlated with different dimensions of climate, with varying strength across geographical and environmental gradients. Thus, under climate change, projected responses potentially include shifts, contractions and even collapses of species’ geographic ranges, with consequences for emergent broad‐scale biogeographic patterns, such as species richness gradients, community turnover and patterns of phylogenetic and functional diversity (Thuiller , Diniz‐Filho et al , Thuiller et al , Loyola et al , Sales et al ).…”

“…Most predictions of shifts in species’ geographic ranges due to climate changes rely on ecological niche models (ENMs hereafter; Franklin , Peterson et al , Guisan et al ). Despite the widespread use of ENMs for predicting the responses of species to climate change, some conceptual and practical limitations have been identified (Peterson et al , Guisan et al ).…”

“…Most predictions of shifts in species’ geographic ranges due to climate changes rely on ecological niche models (ENMs hereafter; Franklin , Peterson et al , Guisan et al ). Despite the widespread use of ENMs for predicting the responses of species to climate change, some conceptual and practical limitations have been identified (Peterson et al , Guisan et al ). A major limitation is that ENMs do not explicitly incorporate population‐level mechanisms, and their predictive abilities rely on the assumption that all underlying mechanisms are captured by the empirical correlations between occurrences and environmental (climatic) factors used as explanatory variables.…”