Bat Roosts in Rock

This guide provides descriptions of when the species of bats resident in British and Ireland use natural and man-made rock habitats, how they use them, and the environment each species occupies within them. This data is part of the Bat Rock Habitat Key project. For the first time it brings together a) historic scientific investigations; b) useful photographic accounts; and c) open access biological records, in a practical narrative. The text encompasses: - Descriptions of the features that a climber, caver or professional ecologist might encounter on and in natural and man-made rock habitats, and within which bats have been recorded roosting. - Recording criteria for both the physical and environmental attributes of different features and situations. - The identification of suitability thresholds against which the recorded information can be compared to assess the likelihood that a specific feature might be exploited by a specific bat species. - Some suggestions for how to avoid mistakes and misery when performing a survey. The idea is that the use of the book will generate standardised biological records that will feed into the online database at www.batrockhabitatkey.co.uk. This data will be analysed to search for patterns that can increase the confidence in the suitability thresholds, build new roost features that deliver the environment each species really wants; their fundamental niche on each environmental gradient.

How animals endure by bending environmental space: Redefining the fundamental niche

ABSTRACTFor 70 years, the fundamental niche, the complete set of environments that allow an individual, population, or species to persist, has shaped ecological thinking. Yet, its properties have eluded quantification, particularly for mobile, cognitively complex organisms. Here, I derive a concise mathematical equation for the fundamental niche and fit it to population growth and distribution data. I find that, within traditionally defined environmental spaces, habitat heterogeneity and behavioural plasticity make the fundamental niche more complex and malleable, but also more predictable, than previously envisaged. This important re-evaluation restores the fundamental niche as a cornerstone of ecological theory and promotes it as a central tool for applied ecology. It quantifies how organisms buffer themselves from change by bending the boundaries of viable environmental space, and offers a framework for designing optimal habitat interventions to protect biodiversity or obstruct invasive species.ONE-SENTENCE SUMMARYThe fundemental niche of animal species

Estimating the fundamental niche: accounting for the uneven availability of existing climates

In the last years, studies that question important conceptual and methodological aspects in the field of ecological niche modeling (and species distribution modeling) have cast doubts on the validity of the existing methodologies. Particularly, it has been broadly discussed whether it is possible to estimate the fundamental niche of a species using presence data. Although it has being identified that the main limitation is that presence data come from the realized niche, which is a subset of the fundamental niche, most of the existing methods lack the ability to overcome it, and then, they fit objects that are more similar to the realized niche. To overcome this limitation, we propose to use the region that is accessible to the species (based on its dispersal abilities) to determine a sampling distribution in environmental space that allow us to quantify the likelihood of observing a particular environmental combination in a sample of presence points. We incorporate this sampling distribution into a multivariate normal model (Mahalanobis model) by creating a weight function that modifies the probabilities of observing an environmental combination in a sample of presences as a way to account for the uneven availability of environmental conditions. We show that the parameters of the modified, weighted-normal model can be approximated by a maximum likelihood estimation approach, and used to draw ellipsoids (confidence regions) that represent the shape of the fundamental niche of the species. We illustrate the application of our model with two worked examples: (i) using presence points of an invasive species and an accessible area that includes only its native range, to evaluate whether the fitted model predicts confirmed establishments of the species outside its native range, and (ii) using presence data of closely related species with known accessible areas to exhibit how the different dispersal abilities of the species constraint a classic Mahalanobis model. Taking into account the distribution of environmental conditions that are accessible to the species indeed affected the estimation of the ellipsoids used to model their fundamental niches.

Ecological niche overlap among species of the genus Zaluzania (Asteraceae) from the dry regions of Mexico

Background and aims – The hypothesis of ecological niche conservatism postulates that closely related species share ecologically similar environments; that is, they tend to maintain the characteristics of their fundamental niche over time. The objective of this study is to evaluate the similarity and equivalence of the ecological niches among species of the genus Zaluzania (Asteraceae), characteristic of the Mexican arid and semi-arid regions, to infer their potential niche conservatism. Methods – Based on critically reviewed herbarium occurrence data, potential distribution models for eight species of Zaluzania were generated using the Maxent algorithm. The overlap between potential distribution areas was then evaluated using equivalence and ecological niche parameters implemented in the ENMTools software; for this we quantified the degree of overlap and similarity between the niches using the equivalence (D) and similarity (I) parameters.Key results – The resulting models show that species display areas of high suitability along the Mexican dry regions, as well as overlapping heterogeneous values. All models showed high AUC (Area Under the Curve) values (> 0.8). The D and I values between each pair of species showed low values of overlap.Conclusions – Each species of the genus shows a fundamental niche distinct from their sister species. The genus thus offers an example of niche divergence among species, with each one adapting to different environmental pressures. Our results do not support the hypothesis of niche conservatism in the genus, suggesting that the species evolved in divergent environments.

Ecological niche overlap among species of the genus Zaluzania (Asteraceae) from the dry regions of Mexico

Background and aims – The hypothesis of ecological niche conservatism postulates that closely related species share ecologically similar environments; that is, they tend to maintain the characteristics of their fundamental niche over time. The objective of this study is to evaluate the similarity and equivalence of the ecological niches among species of the genus Zaluzania (Asteraceae), characteristic of the Mexican arid and semi-arid regions, to infer their potential niche conservatism. Methods – Based on critically reviewed herbarium occurrence data, potential distribution models for eight species of Zaluzania were generated using the Maxent algorithm. The overlap between potential distribution areas was then evaluated using equivalence and ecological niche parameters implemented in the ENMTools software; for this we quantified the degree of overlap and similarity between the niches using the equivalence (D) and similarity (I) parameters.Key results – The resulting models show that species display areas of high suitability along the Mexican dry regions, as well as overlapping heterogeneous values. All models showed high AUC (Area Under the Curve) values (> 0.8). The D and I values between each pair of species showed low values of overlap.Conclusions – Each species of the genus shows a fundamental niche distinct from their sister species. The genus thus offers an example of niche divergence among species, with each one adapting to different environmental pressures. Our results do not support the hypothesis of niche conservatism in the genus, suggesting that the species evolved in divergent environments.