Ecology. 2014 Apr;95(4):978-90. doi: 10.1890/13-0437.1.
The processes that structure assemblages of species in hyper-diverse genera, such as Ficus (Moraceae), are not well understood. Functional diversity of co-occurring species can reveal evidence for assembly processes; however, intraspecific variation may weaken species-level patterns. We studied whether functional and phylogenetic diversity of Ficus species indicated the effects of spatial variation in filters associated with topography or niche partitioning related to resource use and biotic interactions. We also asked whether individual trait patterns supported species-level patterns. We studied six traits (leaf area, succulence, specific leaf area [SLA], maximum diameter breast high [dbh], fruit size, and latex exudation) for 22 Ficus species and 335 individuals > or = 10 cm dbh on a 20-ha forest plot in China. We found that higher elevation was correlated to changes in mean and reduced diversity of five traits, possibly due to frequent disturbances at higher elevations that favored fast-growing, poorly defended species with high SLA. Maximum dbh showed phylogenetic conservatism but high diversity among co-occurring species, suggesting adult stature is an important axis of within-quadrat niche partitioning. At the individual level, trait patterns were qualitatively consistent but were stronger than species-level patterns, especially for the leaf traits with the greatest intraspecific variation (SLA and succulence). Individual-level SLA exhibited the strongest evidence for both traits among and within-quadrat niche partitioning and indicated elevational filtering. Local niche partitioning and elevational filtering likely play an important role in maintaining species and functional diversity in the most speciose genus at our study site. Our results highlight the importance of individual variation, as it may reveal otherwise obscured niche effects.
在高度多样化的属中，如榕属（桑科），结构物种组合的过程还不太清楚。共存物种的功能多样性可以为组合过程提供证据；然而，种内变异可能会削弱种级模式。我们研究了榕属物种的功能和系统发育多样性是否表明与地形相关的过滤器的空间变异或与资源利用和生物相互作用有关的生态位分隔的影响。我们还询问了个体特征模式是否支持种级模式。我们研究了六个特征（叶面积、多汁性、比叶面积[SLA]、胸高处最大直径[dbh]、果实大小和乳汁渗出），涉及中国 20 公顷森林样地中的 22 种榕属物种和 335 株大于或等于 10 cm dbh 的个体。我们发现，较高的海拔与五个特征的平均值和多样性降低有关，这可能是由于高海拔地区频繁发生干扰，有利于具有高 SLA 的快速生长、防御能力差的物种。最大 dbh 表现出系统发育保守性，但共存物种之间具有很高的多样性，这表明成年体型是平方内生态位分隔的一个重要轴。在个体水平上，特征模式在定性上是一致的，但比种级模式更强，尤其是在具有最大种内变异的叶特征（SLA 和多汁性）上。个体水平的 SLA 表现出最强的证据，表明了在平方内和平方间生态位分隔和海拔过滤方面的作用。局部生态位分隔和海拔过滤可能在维持我们研究地点最具物种多样性的属的物种和功能多样性方面发挥重要作用。我们的结果强调了个体变异的重要性，因为它可能揭示了否则被掩盖的生态位效应。
