Logging and human-induced conversion of natural forests into agricultural areas are major drivers of biodiversity loss in the tropics. Anuran larvae can be highly diverse, can reach high biomass and can play important roles in tropical streams; yet, compared to the adult frog communities, relatively little is known about how larval communities respond to disturbance. Information on larvae is highly relevant for amphibian conservation because larvae represent direct evidence of breeding and thus provide a good indicator of species persistence in disturbed habitats. We studied tadpole assemblages in Ranomafana, southeastern part of Madagascar, in streams in a disturbed forest (previously logged forest), at “forest edge” (streams embedded in matrix nearby forest blocks), and compared these to communities in a primary forest. We sampled tadpoles at the microhabitat level (“pools” and “riffles”) in 9 streams. We recorded 27 species with a maximum of 17 species/stream recorded at edge. The three habitats harbored different assemblages, but, as could be expected, more similarities existed among forest habitats than between forest and non-forest habitats. The most and the least diverse communities were recorded at edge and in the disturbed forest, respectively. Assemblages were dominated by one generalist species, and changes in communities were mostly driven by changes in forest specialists, which either decreased in disturbed forest or were replaced by edge specialists outside forest. Although species richness varied, relative abundances were maintained among habitats, suggesting potential compensatory mechanisms in tadpole biomass. Community structure changed at the microhabitat level: pool environments usually harbored relatively higher species richness and abundance than riffles. Our study highlights the relevance of edge habitats for maintaining amphibian diversity and the pronounced negative effects of past logging activities on tadpole communities. Given the diverse roles of tadpoles in streams, changes in community structure potentially affect critical stream ecosystem processes. The study has strong implications for designing buffer zones around protected areas.

中文翻译：

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马达加斯加Ranomafana的森林和农业景观中stream生物多样性的热点

伐木和人为导致的天然林向农业区的转化是热带地区生物多样性丧失的主要驱动力。无ur幼虫可以高度多样化，可以达到较高的生物量，并且可以在热带河流中发挥重要作用；然而，与成年青蛙群落相比，关于幼虫群落如何对干扰做出反应的了解相对较少。有关幼虫的信息与两栖动物的保护高度相关，因为幼虫是繁殖的直接证据，因此可以很好地指示受干扰生境中物种的持久性。我们研究了马达加斯加东南部Ranomafana的nom组合，它们位于受干扰的森林（先前为伐木森林）的溪流中，在“森林边缘”（溪流嵌入附近森林块中的矩阵中），并将其与原始森林中的群落进行比较。我们在9个溪流的微生境水平（“池”和“浅滩”）采样了t。我们记录了27种，边缘处记录的最多为17种/流。这三个生境具有不同的组合，但可以预见，森林生境之间的相似性要比森林生境和非森林生境之间的相似性高。在边缘森林和受干扰的森林中分别记录了最多和最少的群落。集合由一种通配物种主导，而社区的变化主要由森林专家的变化驱动，森林专家的变化要么在受干扰的森林中减少，要么由森林外的边缘专家取代。尽管物种丰富度各不相同，但栖息地之间仍保持相对丰度，表明t生物量具有潜在的补偿机制。群落结构在微生境水平上发生了变化：池环境通常比浅滩具有更高的物种丰富度和丰度。我们的研究强调了边缘生境对维持两栖动物多样性的重要性，以及过去伐木活动对t群落的显着负面影响。鉴于t在河流中的不同作用，群落结构的变化可能会影响河流生态系统的关键过程。该研究对设计保护区周围的缓冲区具有重要意义。鉴于t在河流中的不同作用，群落结构的变化可能会影响河流生态系统的关键过程。该研究对设计保护区周围的缓冲区具有重要意义。鉴于t在河流中的不同作用，群落结构的变化可能会影响河流生态系统的关键过程。该研究对设计保护区周围的缓冲区具有重要意义。