Departamento de Ecologia, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil.
Science. 2013 May 31;340(6136):1086-90. doi: 10.1126/science.1233774.
Local extinctions have cascading effects on ecosystem functions, yet little is known about the potential for the rapid evolutionary change of species in human-modified scenarios. We show that the functional extinction of large-gape seed dispersers in the Brazilian Atlantic forest is associated with the consistent reduction of the seed size of a keystone palm species. Among 22 palm populations, areas deprived of large avian frugivores for several decades present smaller seeds than nondefaunated forests, with negative consequences for palm regeneration. Coalescence and phenotypic selection models indicate that seed size reduction most likely occurred within the past 100 years, associated with human-driven fragmentation. The fast-paced defaunation of large vertebrates is most likely causing unprecedented changes in the evolutionary trajectories and community composition of tropical forests.
局部物种灭绝对生态系统功能会产生级联效应，但人们对于物种在人为改变的环境下快速进化的潜力知之甚少。我们的研究表明，在巴西大西洋森林中，大口种子散布者的功能灭绝与关键棕榈物种种子大小的持续减少有关。在 22 个棕榈种群中，几十年内失去大型鸟类传粉者的地区的种子比未受干扰的森林的种子要小，这对棕榈树的再生产生了负面影响。合并和表型选择模型表明，种子大小的减小很可能在过去 100 年内发生，与人类驱动的破碎化有关。大型脊椎动物的快速灭绝很可能导致热带森林的进化轨迹和群落组成发生前所未有的变化。
