The role of climate, water and biotic interactions in shaping biodiversity patterns in arid environments across spatial scales

Abstract

Aim: Desert ecosystems, with their harsh environmental conditions, hold the key to understanding the responses of biodiversity to climate change. As desert community structure is influenced by processes acting at different spatial scales, studies combining multiple scales are essential for understanding the conservation requirements of desert biota. We investigated the role of environmental variables and biotic interactions in shaping broad and fine-scale patterns of diversity and distribution of bats in arid environments to understand how the expansion of nondesert species can affect the long-term conservation of desert biodiversity.Location: Levant, Eastern Mediterranean. Methods:We combine species distribution modelling and niche overlap statistics with a statistical model selection approach to integrate interspecific interactions into broadscale distribution models and fine-scale analysis of ecological requirements. We focus on competition between desert bats and mesic species that recently expanded their distribution into arid environment following anthropogenic land-use changes. Results:We show that both climate and water availability limit bat distributions and diversity across spatial scales. The broadscale distribution of bats was determined by proximity to water and high temperatures, although the latter did not affect the distribution of mesic species. At the fine-scale, high levels of bat activity and diversity were associated with increased water availability and warmer periods. Desert species were strongly associated with warmer and drier desert types. Range and niche overlap were high among potential competitors, but coexistence was facilitated through fine-scale spatial partitioning of water resources. Main conclusions:Adaptations to drier and warmer conditions allow desert-obligate species to prevail in more arid environments. However, this competitive advantage may disappear as anthropogenic activities encroach further into desert habitats. We conclude that reduced water availability in arid environments under future climate change projections pose a major threat to desert wildlife because it can affect survival and reproductive success and may increase competition over remaining water resources. K E Y W O R D Sbats, desert biogeography, global change, interspecific competition, invasive species, niche overlap, species distribution modelling, water resourcesThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Movement seasonality in a desert-dwelling bat revealed by miniature GPS loggers

“…However, this resource is discontinuous in the environment and temporary in nature, and the wells may be too narrow and deep to allow access during harsh seasons. Although desert-dwelling bats have been shown to converge around the rare waterbodies for water balance restoration and foraging [14, 19], we did not observe bat movement to reach the lake, which was in most cases located at a > 10 km distance from the sites where bats were captured, or their convergence on specific points of the landscape. We consider that, at least during dry seasons, L. frons may be independent from open water sources and rely exclusively on insects for fulfilling both water and energy requirements.…”

“…Although attention directed to desert species in general is still low [11, 12], interest towards desert-dwelling bats has recently increased following concerns regarding their long-term persistence under climate change [13, 14]. Bats are considered a successful order of mammals in deserts thanks to their flight skills and, for desert specialist species, to urine concentration abilities that allow to limit water losses via excretion [5, 15–18].…”

“…Recent studies have identified a fundamental role of waterbodies in supporting diverse desert bat communities and their reproductive success [14, 19, 24, 25]. Permanent water pools have been shown to be particularly important during dry periods, as bats appear to converge around water points for a stable source of water and insects [19].…”

No water, no mating: Connecting dots from behaviour to pathways

“…Availability of water and environmental temperature are undoubtedly the two most pivotal abiotic variables responsible for the abundance and distribution of organisms on this planet [ 13 , 14 ]. Under natural conditions the interaction of these two environmental variables have also been found involved in dictating reproductive output of insects [ 15 ].…”

Ecology of bat species in the arid region of the Daurian steppe at the peak of drought

“…Climate change has altered the distribution and ecology of many species including bats (Lundy et al, 2010;Sherwin et al, 2013;Wu, 2016). One possible mechanism for the change in geographic distribution of bats is that climate change could cause a reduced available fresh water source in arid ecosystems (Sherwin et al, 2013;Razgour et al, 2018). In these ecosystems, bat activity and diversity concentrates near water bodies and associated vegetation (Adams, 2010;Korine et al, 2016;Amorim et al, 2018).…”