Laboratório de Ecologia, Evolução e Conservação de Anfíbios e Répteis, Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista Júlio Mesquita, Rio Claro, São Paulo, Brazil.
Primates. 2024 Jul;65(4):333-339. doi: 10.1007/s10329-024-01128-6. Epub 2024 Apr 2.
The dispersal of large-seeded species strongly depends on medium-sized and large frugivores, such as primates, which are highly susceptible to population declines. In the Atlantic Forest, brown howler monkeys Alouatta guariba are medium-sized folivorous-frugivorous species that are likely to occur in small to large fragments where the largest frugivores are extinct. However, populations of this primate have been suffering from forest fragmentation, habitat loss, hunting, and the direct and indirect effects of yellow fever outbreaks, which increase the importance of understanding their role as seed dispersers and the impacts of their potential loss. The richness and abundance of large-seeded species might also be reduced in smaller fragments, which could directly affect the magnitude of the potential impact of disperser extinction on plant recruitment. Here, we tested the following mutually exclusive predictions on the effect of fragment size on plant richness and relative density of medium- and large-seeded species consumed by brown howler monkeys in fragments smaller than 1500 ha: the number and the relative density of plant species potentially affected by the local extinction of these monkeys will be (1) directly related to forest fragment size, or (2) not related to forest fragment size. Plant richness and the relative density of large- and medium-sized seed species consumed by brown howler monkeys did not vary with fragment size, corroborating our second prediction. Thus, the local extinction of brown howler monkeys would have a similar potentially negative impact on plant regeneration for the range of tested fragment sizes. We discuss the limitations of our results and suggest other lines of enquiry for the refinement of our conclusions.
大种子物种的扩散强烈依赖于中大型食果动物，如灵长类动物，它们极易受到种群减少的影响。在大西洋森林中，褐吼猴 Alouatta guariba 是中等体型的食叶-食果动物，它们可能出现在大型食果动物灭绝的小到大型的碎片中。然而，这种灵长类动物的种群一直受到森林破碎化、栖息地丧失、狩猎以及黄热病爆发的直接和间接影响，这增加了了解它们作为种子传播者的作用以及它们潜在丧失的影响的重要性。大种子物种的丰富度和丰度也可能在较小的碎片中减少，这可能直接影响传播者灭绝对植物繁殖的潜在影响的大小。在这里，我们检验了以下相互排斥的预测，即片段大小对褐吼猴消耗的大种子和中种子物种的丰富度和相对密度的影响：受这些猴子局部灭绝影响的植物物种的数量和相对密度将 (1) 与森林片段大小直接相关，或 (2) 与森林片段大小不相关。褐吼猴消耗的植物丰富度和大、中种子物种的相对密度与片段大小无关，这证实了我们的第二个预测。因此，褐吼猴的局部灭绝将对测试片段范围内的植物再生产生类似的潜在负面影响。我们讨论了我们结果的局限性，并提出了其他研究方向来完善我们的结论。
