Print PageSpecies range represents ecological niche of a species, and is determined by abiotic and biotic factors, such as climate, population demography, and interactions with other species. Although interspecific competition could be an important biotic factor determining the range of a species, it is difficult to ascertain whether ranges of parapatrically distributed species are restricted by competition. In this study, I used ecological niche modeling (ENM) to project the potential distributions of two parapatric species, the recently diverged Vinous-throated Parrotbill (Paradoxornis webbianus) and Ashy-throated Parrotbill (P. alphonsianus), in southwestern China. From their potential distributions, I infer competitive exclusion and niche differentiation between the two species.
Results/Conclusions
Results of the ENM models revealed that these two parrotbills share a sympatric region yet their distributions within the region do not overlap. The projected sympatric region is primarily in Chengdu Plain and Guizhou. Many of the environmental variables examined have different ranges between areas occupied by each of the two parrotbills in the sympatric region: the Ashy-throated Parrotbill occupying areas of higher altitudes with relatively stable temperature than the Vinous-throated Parrotbill. These results suggest that the two recently diverged parrotbills have shown some degree of niche differentiation, and that interspecific competition might play a critical role in determining their distributions.
