Adam H. Porter
Howard Ginsberg
Julie V. Bednarski
Jeremy Houser
Elizabeth M. Jakob
2011
<p><span>Invasive spiders pose potential threats to native spiders. In 2002, the European spider </span><i><span class="named-content" data-type="species">Linyphia triangularis</span></i><span> (Clerck, 1757) (Araneae: Linyphiidae) was discovered in all but one county in Maine. At Acadia National Park, we conducted a 4-year study of </span><i>L. triangularis</i><span> and three native linyphiid species of a similar size (</span><i><span class="named-content" data-type="species">Frontinella communis</span></i><span> (Hentz, 1850), </span><i><span class="named-content" data-type="species">Pityohyphantes subarcticus</span></i><span> Chamberlin and Ivie, 1943, and </span><i><span class="named-content" data-type="species">Neriene radiata</span></i><span> (Walckenaer, 1842)). Using line-transect surveys, we measured population densities in coastal and forest habitat. The density of </span><i>L. triangularis</i><span> varied across years but was always significantly higher on the coast than in the forest. In contrast, only one native species was present on the coast and at very low numbers. Coastal </span><i>L. triangularis</i><span> were larger and in better condition than those in the forest, and numbers and biomass of insect prey were also higher on the coast. In 2 years, we also conducted transects at a second coastal location in Maine where the invader was at low density. At that site, native densities were substantially higher than at either Acadia site. Our data are consistent with the hypothesis that </span><i>L. triangularis</i><span> is reducing populations of native spiders. Companion studies suggest that </span><i>L. triangularis</i><span> negatively impacts natives by usurping both web sites and webs.</span></p>
application/pdf
10.1139/z11-050
en
NRC Research Press
A 4-year study of invasive and native spider populations in Maine
article