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Biodivers Conserv (2014) 23:22732287
DOI 10.1007/s10531-014-0722-6
ORIGINAL PAPER
Severin D. H. Irl Manuel J. Steinbauer Lilith Epperlein
David E. V. Harter Anke Jentsch Susanne Patz
Christian Wohlfart Carl Beierkuhnlein
Received: 16 August 2013 / Revised: 13 April 2014 / Accepted: 6 May 2014 / Published online: 28 June 2014 Springer Science+Business Media Dordrecht 2014
Abstract Roadsides are habitats with very specic environmental conditions, often substantially differing from their natural surroundings. However, roads can have a positive effect on local vascular plant species richness. Endemic species on oceanic islands are considered to be less disturbance-adapted than native non-endemics and thus should be negatively affected by roads. Islands provide optimal conditions for testing this, as they possess a large share of clearly dened endemic species. This study focuses on a comparison of endemic plant species in roadside and surrounding communities and the interacting effects of elevation, vegetation type and trade wind-induced precipitation differences. We applied 96 circular plots with 50 m radius along two elevational gradients on the eastern (humid) and western (dry) slope of La Palma, Canary Islands, ranging from 100 to 2,400 m. Interestingly, we found roads to have a signicant positive effect on endemic richness and the percentage of endemics as well as the same tendency for plant species richness after correcting for elevation and precipitation. Endemic species turnover was relatively high. The opening of cliffs during construction and, not to be overlooked, the protection from disturbances such as re and omnipresent introduced herbivores (mainly rabbits or goats) probably leads to a positive effect of roads on endemics. In addition, many endemics might prot from species-specic dispersal capabilities well suited for roadside conditions. However, we do not argue for the use or even construction of roads for nature conservation but suggest protecting existing endemic populations because natural areas have a higher conservation value.
Communicated by Daniel Sanchez Mata.
Electronic supplementary material The online version of this article (doi:http://dx.doi.org/10.1007/s10531-014-0722-6
Web End =10.1007/s10531-014-0722-6 ) contains supplementary material, which is available to authorized users.
S. D. H. Irl (&) A. Jentsch S. Patz
Department of Disturbance Ecology, University of Bayreuth, 95447 Bayreuth, Germany e-mail: [email protected]
M. J. Steinbauer L. Epperlein D. E. V. Harter C. Wohlfart C. Beierkuhnlein
Department of Biogeography, University of Bayreuth, 95447 Bayreuth, Germany