The effect of shrub removal on small mammals in costal sand dunes, Nahal Alexander National Park, Israel
Published source details
Kutiel P., Peled Y. & Geffen E. (2000) The effect of removing shrub cover on annual plants and small mammals in a coastal sand dune ecosystem. Biological Conservation, 94, 235-242
Published source details Kutiel P., Peled Y. & Geffen E. (2000) The effect of removing shrub cover on annual plants and small mammals in a coastal sand dune ecosystem. Biological Conservation, 94, 235-242
The sand dunes of the 190 km long Israeli coastal plain are threatened with development and pollution, with less than 17% of sand dunes remaining and under 5% formally protected. Furthermore, in protected areas, shifting dunes once formed long-narrow ridges, with less than 5% vegetation cover, but over the last fifty years they have lost their longitudinal shape and have become vegetated by shrubs and dwarf-shrubs forming up tp 80 % cover. It has been suggested that preventing pasturage in designated nature reserves has this allowed succession to occur. These sand dunes, however, support the only endemic mammal species in Israel, both rodents - Buxton's jird Meriones sacramenti and Anderson's gerbil Gerbillus andersoni allenbyi. In this study, the impact of above-ground removal of woody vegetation cover on the mammal species composition, species richness and diversity is examined.
Woody shrub removal: In September 1995, all of the above ground woody vegetation was manually removed (using saws and pruning hooks) from two 50 x 50 m plots, each separated by over 200 m. Two 50 x 50 m control plots, which were similar in plant cover and composition to the cleared plots, were paired with a cleared plot and located within 50-200 m.
Small mammal live-trapping: From December 1995 until September 1996, thirty-six Sherman collapsible traps (23 x 8 x 9 cm), baited with bread and peanut butter, were set on a 10 m grid set in the centre of the plots. Each month and starting on the same night, every plot was censused for four consecutive nights, giving a total of 5,184 trap/nights. Traps were set at dusk and examined the following morning, after which they were closed. In the winter, traps were covered with small plastic bags to prevent rain from entering, and partly filled with cotton wool to provide insulation. Trapped mammals were identified to species, toe clipped for individual identification and released at the capture site.
Small mammal community: Anderson's gerbil Gerbillus andersoni allenbyi and house mouse Mus musculus were the most abundant small mammals captured overall. However, the control and cleared plots revealed very different species compositions.
Cleared plots: A total of 125 small mammls were captured. Of theses 107 (85.6%) were gerbils, eight (6.4%) Tristram's jird Meriones tristrami , 6 (4.8%), house mouse, 1 (0.8%) black rat Rattus rattus, and 3 (2.4%) white-toothed shrew Crocidura russula.
Conrol plots: In control plots, a similar number, but a lower percentage, of gerbil were caught (124 of 263 total captures, 47.1%), fewer Tristram's jird were captured (3, 1.1%), eighteen times more house mouse (109, 41.4%), twelve times more black rat (12, 4.6%), and five times more white-toothed shrew (15, 5.7%).
Conclusions: While the sand dune specialist Anderson's gerbil continued to thrive and Tristram's jird increased in abundance in cleared compared to control plots, other small mammals were generally found at much lower densities. Consequently, scrub removal seems to have been successful at promoting the two rare sand dune rodent endemics. (See also Case 397 for the effect of this management on annual plants).
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