Department of Environmental Sciences, University of Toledo, Toledo, OH 43606-3328, USA.
Conserv Biol. 2010 Jun;24(3):737-46. doi: 10.1111/j.1523-1739.2009.01430.x. Epub 2010 Jan 22.
Quality of the agricultural matrix profoundly affects biodiversity and dispersal in agricultural areas. Vegetatively complex coffee agroecosystems maintain species richness at larger distances from the forest. Epiphytes colonize canopy trees and provide resources for birds and insects and thus effects of agricultural production on epiphytes may affect other species. We compared diversity, composition, and vertical stratification of epiphytes in a forest fragment and in two coffee farms differing in management intensity in southern Mexico. We also examined spatial distribution of epiphytes with respect to the forest fragment to examine quality of the two agricultural matrix types for epiphyte conservation. We sampled vascular epiphytes in a forest fragment, a shade polyculture farm, and a shade monoculture farm at 100 m, 200 m, and 400 m from the forest. Epiphyte and orchid richness was greater in the forest than in the monoculture but richness was similar in the forest and polyculture farm. Epiphyte species composition differed with habitat type, but not with distance from the forest. In the forest, epiphytes were distributed throughout tree canopies, but in the farms, epiphytes were primarily found on trunks and larger branches. Epiphyte richness and species similarity to forest species declined with distance from the forest fragment in the monoculture, but richness and similarity to forest species did not decline with distance from forest in the polyculture. This suggests polyculture coffee has greater conservation value. In contrast, monoculture coffee is likely a sink habitat for epiphytes dispersing from forests into coffee. Coffee farms differ from forests in terms of the habitat they provide and species composition, thus protecting forest fragments is essential for epiphyte conservation. Nonetheless, in agricultural landscapes, vegetatively complex coffee farms may contribute to conservation of epiphytes more than other agricultural land uses.
农业基质的质量对农业区的生物多样性和扩散有深远的影响。具有复杂植被的咖啡农业生态系统在离森林更远的地方保持物种丰富度。附生植物会在树冠上定殖，并为鸟类和昆虫提供资源，因此农业生产对附生植物的影响可能会影响到其他物种。我们比较了墨西哥南部一个森林片段和两个管理强度不同的咖啡农场中附生植物的多样性、组成和垂直分层。我们还检查了附生植物在空间上相对于森林片段的分布情况，以研究两种农业基质类型对附生植物保护的质量。我们在森林片段、遮荫混作农场和遮荫单作农场中，在距离森林 100 米、200 米和 400 米的地方，对维管束附生植物进行了采样。森林中的附生植物和兰花的丰富度大于单作农场，但森林和混作农场的丰富度相似。附生植物的物种组成因栖息地类型而异，但与离森林的距离无关。在森林中，附生植物分布在树冠的各个部位，但在农场中，附生植物主要生长在树干和较大的树枝上。在单作农场中，随着与森林片段距离的增加，附生植物的丰富度和与森林物种的相似性呈下降趋势，但在混作农场中，与森林物种的丰富度和相似性并不随距离的增加而下降。这表明混作咖啡具有更大的保护价值。相比之下，单作咖啡可能是森林中扩散到咖啡中的附生植物的汇栖息地。咖啡农场与森林在提供的栖息地和物种组成方面存在差异，因此保护森林片段对于附生植物的保护至关重要。尽管如此，在农业景观中，具有复杂植被的咖啡农场可能比其他农业土地利用方式更有助于保护附生植物。
