Integrating Life Stages into Ecological Niche Models: A Case Study on Tiger Beetles

Abstract

Detailed understanding of a species’ natural history and environmental needs across spatial scales is a primary requisite for effective conservation planning, particularly for species with complex life cycles in which different life stages occupy different niches and respond to the environment at different scales. However, niche models applied to conservation often neglect early life stages and are mostly performed at broad spatial scales. Using the endangered heath tiger beetle (Cicindela sylvatica) as a model species, we relate presence/absence and abundance data of locally dispersing adults and sedentary larvae to abiotic and biotic variables measured in a multiscale approach within the geographic extent relevant to active conservation management. At the scale of hundreds of meters, fine-grained abiotic conditions (i.e., vegetation structure) are fundamental determinants of the occurrence of both life stages, whereas the effect of biotic factors is mostly contained in the abiotic signature. The combination of dense heath vegetation and bare ground areas is thus the first requirement for the species’ preservation, provided that accessibility to the suitable habitat is ensured. At a smaller scale (centimetres), the influence of abiotic factors on larval occurrence becomes negligible, suggesting the existence of important additional variables acting within larval proximity. Sustained significant correlations between neighbouring larvae in the models provide an indication of the potential impact of neighbourhood crowding on the larval niche within a few centimetres. Since the species spends the majority of its life cycle in the larval stage, it is essential to consider the hierarchical abiotic and biotic processes affecting the larvae when designing practical conservation guidelines for the species. This underlines the necessity for a more critical evaluation of the consequences of disregarding niche variation between life stages when estimating niches and addressing effective conservation measures for species with complex life cycles.

Integrating demography, dispersal and interspecific interactions into bird distribution models

“…I suggest developing standard workflows for identifying key life stages of birds in the models, for example using traits, and for identifying the relevant niche axes and scales. Simple life‐stage specific SDMs (Taboada et al ) can be overlaid to distinguish, for example, source habitats, which contribute both to survival and reproduction, from sink habitats, which do not support reproduction but may nevertheless allow survival or are even important refuges during winter or other stressful times (Naves et al ), or to distinguish habitats that promote dispersal (Rotllan‐Puig and Traveset ). Following the hypothesis that source populations should be more stable over time than sink populations, accurate life‐cycle SDMs should be better at explaining population stability over time than conventional SDMs (Oliver et al ).…”

Effects of functional traits on the prediction accuracy of species richness models

“…For accurate biodiversity predictions, it seems also crucial to consider where the species is able to reproduce. Species' demography is hence an important aspect that needs to be considered (Normand et al ., ; Thuiller et al ., ), for example by integrating life stages into niche models (Taboada et al ., ).…”

Understanding the life histories of amphidromous fish by integrating otolith‐derived growth reconstructions, post‐larval migrations and reproductive traits

“…Common to all species with complex life histories, an understanding of the requirements and potential bottlenecks across each life history phase is key to effective conservation and management (Taboada, von Wehrden, & Assmann, ). Amphidromous species are understudied relative to other diadromous life history types (McDowall, ) largely because of the practical and logistical difficulties associated with tracking the origins and movements of larval fish in a marine or lacustrine pelagic habitat.…”