Habitat use, but not gene flow, is influenced by human activities in two ecotypes of Egyptian fruit bat (Rousettus aegyptiacus)

Abstract

Understanding the ecological, behavioural and evolutionary response of organisms to changing environments is of primary importance in a human-altered world. It is crucial to elucidate how human activities alter gene flow and what are the consequences for the genetic structure of a species. We studied two lineages of the Egyptian fruit bat (Rousettus aegyptiacus) throughout the contact zone between mesic and arid Ecozones in the Middle East to evaluate the species' response to the growing proportion of human-altered habitats in the desert. We integrated population genetics, morphometrics and movement ecology to analyse population structure, morphological variation and habitat use from GPS- or radio-tagged individuals from both desert and Mediterranean areas. We classified the spatial distribution and environmental stratification by describing physical-geographical conditions and land cover. We analysed this information to estimate patch occupancy and used an isolation-by-resistance approach to model gene flow patterns. Our results suggest that lineages from desert and Mediterranean habitats, despite their admixture, are isolated by environment and by adaptation supporting their classification as ecotypes. We found a positive effect of human-altered habitats on patch occupancy and habitat use of fruit bats by increasing the availability of roosting and foraging areas. While this commensalism promotes the distribution of fruit bats throughout the Middle East, gene flow between colonies has not been altered by human activities. This discrepancy between habitat use and gene flow patterns may, therefore, be explained by the breeding system of the species and modifications of natal dispersal patterns.

Spatial networks differ when food supply changes: Foraging strategy of Egyptian fruit bats

“…Alternatively, fruit bats are not constrained by a single choice, thus they actively select different food sources. From the end of summer until spring, the bats relied mainly on harvestable fruit grown for export; indeed, frequent use of human-modified areas by Egyptian fruit bats has been previously reported in Mediterranean and desert environments [72]. During harvesting season, bats come to contact with people more often, which can also force them to move between patches to avoid conflict.…”

Pan African phylogeography and palaeodistribution of rousettine fruit bats: Ecogeographic correlation with Pleistocene climate vegetation cycles

“…Respective scenarios would involve ecological adaptation of the lineages ancestral to recent haplogroups to different habitats (closed canopy rain forest vs. open canopy forest) within refugia or microrefugia, possibly under the vanishing refugia model. Concordant genetic and phenotypic differentiation associated with habitat transition, the basic prerequisite of ecotypic variation and adaptive speciation models, was recognized in R. aegyptiacus living in the Mediterranean versus desert biomes of the Middle East (Centeno‐Cuadros et al, ). In the Rousettus case, adaptive differentiation could have occurred in situ (Schilthuizen, ), facilitated by the altitudinal, topographic and ecological complexity and instability of East Africa, a biodiversity refuge and speciation hotspot (Liu, Prugnolle, Manica, & Balloux, ).…”

“…Ficus , Phoenix or Ceratonia ) to the Middle East, which were domesticated later during the onset of horticulture and agriculture, mirroring the overlap of fruit bat and human (primate) trophic niches involving frugivory. The current diet of R. aegyptiacus in the xeric (and seasonally very cold) biomes of the Middle East relies largely on agricultural and non‐native plants of tropical and subtropical ancestry; for example figs, dates or carob (Centeno‐Cuadros et al, ; Korine, Izhaki, & Arad, ). In the Anthropocene, human impact affecting trophic and roosting opportunities modulated the movement ecology of Rousettus (Centeno‐Cuadros et al, ), as is illustrated also by the overlap of its current range and cropland (Figure ) and anthropogenic biomes (Figure S5).…”

“…The current diet of R. aegyptiacus in the xeric (and seasonally very cold) biomes of the Middle East relies largely on agricultural and non‐native plants of tropical and subtropical ancestry; for example figs, dates or carob (Centeno‐Cuadros et al, ; Korine, Izhaki, & Arad, ). In the Anthropocene, human impact affecting trophic and roosting opportunities modulated the movement ecology of Rousettus (Centeno‐Cuadros et al, ), as is illustrated also by the overlap of its current range and cropland (Figure ) and anthropogenic biomes (Figure S5). This process is likely facilitated by destruction of forest habitats, with many consequences including transmission of zoonotic diseases (Rulli, Santini, Hayman, & D'Odorico, ; Wolfe, Daszak, Kilpatrick, & Burke, ).…”

Wolves at the crossroad: Fission–fusion range biogeography in the Western Carpathians and Central Europe

“…Respective areas coincided well with the biogeographic regions of Europe. The occurrence of distinct genetic clusters associated with particular environments in the absence of physical barriers to gene flow (isolation by environment; Wang & Bradburd, ) has been accepted as an indication of ecotypic variation in grey wolf (Carmichael et al., ; Czarnomska et al., ; Musiani et al., ; Pilot et al., ) and other species of highly mobile mammals (Centeno‐Cuadros et al., ; Dalén et al., ; Moura et al., ; Sacks, Brown, & Ernest, ; Wolf et al., ). Further sampling representing Eastern and Southern Carpathians and the genomic approach is necessary to study this phenomenon in detail in wolves.…”