Souza Danielle G, Santos Jean C, Oliveira Marcondes A, Tabarelli Marcelo
Programa de Pós-Graduação em Biologia Vegetal, Universidade Federal de Pernambuco, Recife, PE 50670-420, Brazil (
Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, MG 38405-320, Brazil (
Environ Entomol. 2016 Oct;45(5):1161-1169. doi: 10.1093/ee/nvw115. Epub 2016 Aug 22.
Impacts of habitat loss and fragmentation on specialist herbivores have been rarely addressed. Here we examine the structure of plant and galling insect assemblages in a fragmented landscape of the Atlantic forest to verify a potential impoverishment of these assemblages mediated by edge effects. Saplings and galling insects were recorded once within a 0.1-ha area at habitat level, covering forest interior stands, forest edges, and small fragments. A total of 1,769 saplings from 219 tree species were recorded across all three habitats, with differences in terms of sapling abundance and species richness. Additionally, edge-affected habitats exhibited reduced richness of both host-plant and galling insects at plot and habitat spatial scale. Attack levels also differed among forest types at habitat spatial scale (21.1% of attacked stems in forest interior, 12.4% in small fragments but only 8.5% in forest edges). Plot ordination resulted in three clearly segregated clusters: one formed by forest interior, one by small fragments, and another formed by edge plots. Finally, the indicator species analysis identified seven and one indicator plant species in forest interior and edge-affected habitats, respectively. Consequently, edge effects lead to formation of distinct taxonomic groups and also an impoverished assemblage of plants and galling insects at multiple spatial scales. The results of the present study indicate that fragmentation-related changes in plant assemblages can have a cascade effects on specialist herbivores. Accordingly, hyperfragmented landscapes may not be able to retain an expressive portion of tropical biodiversity.
栖息地丧失和破碎化对特化食草动物的影响鲜有研究。在此，我们研究了大西洋森林破碎化景观中植物和瘿蚊昆虫群落的结构，以验证由边缘效应介导的这些群落的潜在 impoverishment。在栖息地水平的 0.1 公顷区域内对幼树和瘿蚊昆虫进行了一次记录，涵盖森林内部林分、森林边缘和小碎片。在所有这三种栖息地中总共记录了来自 219 种树种的 1769 株幼树，幼树丰度和物种丰富度存在差异。此外，在样地和栖息地空间尺度上，受边缘影响的栖息地中寄主植物和瘿蚊昆虫的丰富度均降低。在栖息地空间尺度上，不同森林类型的受攻击水平也有所不同（森林内部 21.1%的茎受到攻击，小碎片中为 12.4%，但森林边缘仅为 8.5%）。样地排序产生了三个明显分离的聚类：一个由森林内部形成，一个由小碎片形成，另一个由边缘样地形成。最后，指示物种分析分别在森林内部和受边缘影响的栖息地中确定了 7 种和 1 种指示植物物种。因此，边缘效应导致在多个空间尺度上形成不同的分类群，以及植物和瘿蚊昆虫群落的 impoverishment。本研究结果表明，与破碎化相关的植物群落变化可能对特化食草动物产生级联效应。因此，高度破碎的景观可能无法保留热带生物多样性的很大一部分。
