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Ben Gurion University of the Negev (2012)

Reducing the competitive load on desert bat communities by hampering the drinking ability of an invasive bat species, Kuhl’s pipistrelle (Pipistrellus kuhlii)

Greenfeld, Asael

Titre : Reducing the competitive load on desert bat communities by hampering the drinking ability of an invasive bat species, Kuhl’s pipistrelle (Pipistrellus kuhlii)

Auteur : Greenfeld, Asael

Université de soutenance : Ben Gurion University of the Negev

Grade : Master of Science (MS) 2012

Mots clés : Pipistrellus — Habitat ; Competition (Biology)

Résumé partiel
Among the species comprising the bat community of the Negev desert in Israel, three have expanded their range into the desert from Mediterranean habitats, probably due to anthropogenic developments such as the addition of bodies of open water and lights. The abundance and activity of bats in the desert is affected by the distribution of bodies of open water, which are used by bats for drinking and foraging sites. One of the species that has penetrated the Negev from Mediterranean habitats is Kuhl’s pipistrelle (Pipistrellus kuhlii), the most common bat in Israel. Kuhl’s pipistrelle competes for foraging habitats and food with three other species of bats (P.rueppellii, Hypsugo bodenheimeri and Eptesicus bottae), comprising the “background cluttered space” foraging guild. Kuhl’s pipistrelle drinks more frequently than the other species of its guild and requires a clear “swoop zone” to drink. I hypothesized that Kuhl’s pipistrelle uses newly established water bodies of II open to expand into desert habitats. To reduce the competitive load that Kuhl’s pipistrelle has on desert dwelling species, I proposed and tested a management tool to reduce the ability of Kuhl’s pipistrelle to drink from open bodies of water. I predicted that, by installing obstructions above the water surface, I could reduce the drinking ability of Kuhl’s pipistrelle, thus reducing their activity. First, using acoustic methods, I surveyed natural and artificial bodies of open water in the Ramon region in order to learn the current limits of Kuhl’s pipistrelle’s range expansion and to study the mechanisms of its expansion. To study the effect of obstructions on the water surface, I did field experiments. In each experiment, the manipulation and control treatments were alternated, and the activity levels of the different species present were monitored by acoustic methods. I found in the survey that Kuhl’s pipistrelle are abundant in the Central Negev Highlands, but absent from Makhtesh Ramon, and found activity levels of Kuhl’s pipistrelle high in natural sites as well as in artificial ones. In the first field experiment that tuck place in a swimming pool, I managed to prevent Kuhl’s pipistrelle’s drinking by obstructing the water surface and leaving just a 1x1m of “swoop zone”. In the second manipulation experiment, in natural ponds in the Zin valley, I found that the obstructions had no effect on activity levels or species composition. This might have been the result of the proximity of untreated ponds to manipulated ponds in the study area. In the third experiment, I chose isolated natural ponds throughout the Negev. I found that, in some of the ponds, the manipulation significantly reduced Kuhl’s pipistrelle activity. This reduction was observed in ponds that initially had higher activity of Kuhl’s pipistrelle then of desert dwelling species.

Présentation (BGU)

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Page publiée le 5 avril 2015, mise à jour le 26 novembre 2018