Almeida-Gomes Mauricio, de Siqueira Andreza Soares, Borges-Júnior Vitor Nelson Teixeira, Tozzi Maria Anita, Silva Rodrigo da Fonseca da, Vieira Marcus Vinícius, Prevedello Jayme Augusto
Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Campo Grande, Brazil.
Departamento de Ecologia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.
J Anim Ecol. 2025 Jul;94(7):1449-1460. doi: 10.1111/1365-2656.70081. Epub 2025 Jun 12.
Isolated trees are conspicuous in fragmented landscapes and are often considered 'keystone structures', due to their significant ecological role despite occupying small areas. They are also regarded as 'biodiversity foci', because they may support higher abundance and species richness than nearby open areas. However, these suggestions have not been tested experimentally yet. Using experimental ponds and amphibians as a model system, we tested the importance of isolated trees for biological communities in a biodiversity hotspot, the Atlantic Forest. We built and sampled 28 artificial ponds, 10 near the edge of a continuous forest, nine beneath isolated trees and nine in open pasture. To test for differences in amphibian community structure among experimental treatments, we quantified community abundance, local species richness and community composition. We also tested whether the abundance of the four numerically dominant species in the ponds (Physalaemus signifer, Leptodactylus latrans, Rhinella ornata and Scinax aff. x-signatus) differed among treatments. Finally, we compared total (landscape-level) species richness among treatments. Ponds located beneath isolated trees and near forest edges had a higher community abundance and abundance of P. signifer and R. ornata, as well as a higher total (landscape-level) species richness than ponds located in open pasture. Ponds beneath isolated trees had a similar community composition to ponds near the edge of the continuous forest, whereas open pasture communities had a markedly different community composition. Our results provide experimental evidence that isolated trees contribute to increase total (landscape-level) species richness and community abundance of anurans in ponds in deforested areas, making local communities more similar to those found near forest edges. We recommend protecting and planting isolated trees across deforested areas, particularly near natural ponds, as well as restoring ponds near isolated trees. These relatively low-cost actions can contribute substantially to increasing the abundance and species richness of anuran communities in fragmented landscapes.
在破碎化景观中，孤立的树木十分显眼，尽管它们占地面积小，但因其具有重要的生态作用，常被视为“关键结构”。它们还被视为“生物多样性焦点”，因为与附近的开阔区域相比，它们可能支持更高的生物丰度和物种丰富度。然而，这些观点尚未经过实验验证。我们以实验池塘和两栖动物作为模型系统，在生物多样性热点地区大西洋森林中，测试了孤立树木对生物群落的重要性。我们建造并采样了28个人工池塘，其中10个靠近连续森林边缘，9个在孤立树木下方，9个在开阔牧场中。为了测试不同实验处理下两栖动物群落结构的差异，我们对群落丰度、本地物种丰富度和群落组成进行了量化。我们还测试了池塘中数量占优势的四个物种（饰纹泡蟾、豹纹雨蛙、饰纹角花蟾和一种斯氏蛙）的丰度在不同处理之间是否存在差异。最后，我们比较了不同处理之间的总（景观水平）物种丰富度。位于孤立树木下方和森林边缘附近的池塘，其群落丰度、饰纹泡蟾和饰纹角花蟾的丰度以及总（景观水平）物种丰富度均高于开阔牧场中的池塘。孤立树木下方的池塘群落组成与连续森林边缘附近的池塘相似，而开阔牧场群落的组成则明显不同。我们的结果提供了实验证据，表明孤立树木有助于增加森林砍伐地区池塘中无尾两栖类的总（景观水平）物种丰富度和群落丰度，使当地群落更类似于森林边缘附近的群落。我们建议在森林砍伐地区，特别是在天然池塘附近，保护和种植孤立树木，并恢复孤立树木附近的池塘。这些成本相对较低的行动可以极大地有助于增加破碎化景观中无尾两栖类群落的丰度和物种丰富度。
