Tree recruitment in an empty forest.
Tree recruitment in an empty forest.
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DOI：
10.1890/07-0479.1
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发表时间：
2008-06
期刊：
影响因子：
4.8
通讯作者：
J. Terborgh;Gabriela Nuñez;Iturri;Nigel;A. C.;Pitman;Fernando;-H.;Cornejo Valverde;Patrícia Alvarez;Varun Swamy;Elizabeth;-G.;Pringle;E. C.;Timothy Paine
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文献类型：
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作者：
J. Terborgh;Gabriela Nuñez;Iturri;Nigel;A. C.;Pitman;Fernando;-H.;Cornejo Valverde;Patrícia Alvarez;Varun Swamy;Elizabeth;-G.;Pringle;E. C.;Timothy Paine
为了评估猎杀大型脊椎动物如何改变热带森林的招募过程，我们比较了秘鲁东南部里约马努泛滥平原上两片结构和成分相似的森林的树苗群。大型脊椎动物在一个地点博卡马努(BM)严重枯竭，而另一个地点Cocha Cashu生物站(CC)支撑着一个完整的动物群。在这两个地点，我们采样的小(或=1米高，或=1厘米和或=10厘米胸径)被定位和识别。这种设计确保了任何幼树至少50米(BM)或55米(CC)内的所有同种成虫都有已知的位置。我们使用Janzen-Connell模型对BM的幼树群体与CC进行了五个预测：(1)总的幼树招募减少，(2)通过非生物方式分散的物种的招募增加，(3)物种的相对丰富度改变，(4)大种子物种在那些表现出较低招募的物种中突出，(5)幼树在BM很少或没有向成虫聚集的趋势。我们的结果证实了这些预测的每一个。从表面价值来看，证据表明，在BM，很少有物种在人口统计上是稳定的，高达28%的物种在增加，72%的物种在减少。扩散功能的丧失使得非生物和由小鸟和哺乳动物散布的物种可以取代由大型鸟类和哺乳动物散布的物种。虽然我们认为这些结论是初步的，但从长远来看，所观察到的树木组成的方向性变化类型可能会导致生物多样性的丧失，并对动植物群落造成负反馈。我们的结果表明，防止热带乔木群落成分变化和可能的多样性丧失的最好方法，也可能是唯一的方法，就是禁止狩猎。
To assess how the decimation of large vertebrates by hunting alters recruitment processes in a tropical forest, we compared the sapling cohorts of two structurally and compositionally similar forests in the Rio Manu floodplain in southeastern Peru. Large vertebrates were severely depleted at one site, Boca Manu (BM), whereas the other, Cocha Cashu Biological Station (CC), supported an intact fauna. At both sites we sampled small (> or =1 m tall, or =1 cm and or =10 cm dbh were mapped and identified. This design ensured that all conspecific adults within at least 50 m (BM) or 55 m (CC) of any sapling would have known locations. We used the Janzen-Connell model to make five predictions about the sapling cohorts at BM with respect to CC: (1) reduced overall sapling recruitment, (2) increased recruitment of species dispersed by abiotic means, (3) altered relative abundances of species, (4) prominence of large-seeded species among those showing depressed recruitment, and (5) little or no tendency for saplings to cluster closer to adults at BM. Our results affirmed each of these predictions. Interpreted at face value, the evidence suggests that few species are demographically stable at BM and that up to 28% are increasing and 72% decreasing. Loss of dispersal function allows species dispersed abiotically and by small birds and mammals to substitute for those dispersed by large birds and mammals. Although we regard these conclusions as preliminary, over the long run, the observed type of directional change in tree composition is likely to result in biodiversity loss and negative feedbacks on both the animal and plant communities. Our results suggest that the best, and perhaps only, way to prevent compositional change and probable loss of diversity in tropical tree communities is to prohibit hunting.