Laboratorio Ecotono-CRUB, Universidad Nacional del Comahue and INIBIOMA, Pasaje Gutierrez 1125, 8400 San Carlos de Bariloche, Río Negro, Argentina.
Ecol Appl. 2010 Sep;20(6):1491-7. doi: 10.1890/09-1626.1.
Island biogeography theory predicts that species richness increases with habitat area and declines with isolation. We expand this framework to address changes in the number of links and species in pollination webs from 12 isolated hills, ranging in area from tens to thousands of hectares, immersed in the agriculture matrix of the Argentine Pampas. We also studied whether total interaction frequency is partitioned more evenly among individual links in richer webs. Our results reveal a direct effect of area on the number of links and species present in each pollination web. However, link richness increased twofold faster than species richness with area. These area effects were not confounded by sampling effort or correlated incidence of exotic species, despite widespread habitat disturbance. Habitat proximity, an inverse measure of isolation, had a marginally significant influence on link but not on species richness. Increased link number was associated with decreasing dominance by any particular interaction and increasing interaction evenness. Despite the strong area effect, a rich pollination web sampled from a small, protected sierra suggests that simple conservation measures, such as reduced grazing and fire suppression, may effectively preserve much local interaction diversity.
岛屿生物地理学理论预测，物种丰富度随栖息地面积的增加而增加，随隔离程度的增加而减少。我们扩展了这个框架，以解决来自阿根廷潘帕斯农业基质中 12 个孤立丘陵的授粉网络中连接数量和物种的变化，这些丘陵的面积从几十公顷到几千公顷不等。我们还研究了总相互作用频率是否在更丰富的网络中更均匀地分配给各个连接。我们的结果表明，面积对每个授粉网络中存在的连接数量和物种数量有直接影响。然而，与物种丰富度相比，连接丰富度随面积的增加快了两倍。尽管广泛存在栖息地干扰，但这些面积效应并没有与抽样努力或外来物种的相关发生率混淆。生境接近度，隔离的逆度量，对连接的丰富度有边缘显著的影响，但对物种的丰富度没有影响。连接数量的增加与任何特定相互作用的优势度降低和相互作用均匀度增加有关。尽管存在强烈的面积效应，但从一个小的、受保护的山脉中采样的丰富授粉网络表明，简单的保护措施，如减少放牧和抑制火灾，可能有效地保护本地的大部分相互作用多样性。
