COS 106-5 - Competition sets upper and lower elevational range limits of burying beetles (Nicrophorus nepalensis)

Wednesday, August 9, 2017: 2:50 PM
C122, Oregon Convention Center
Shih-Fan Chan1, Wei-Kai Shih2, An-Yu Chang1, Sheng-Feng Shen1 and I-Ching Chen2, (1)Biodiversity Research Center, Academia Sinica, Taiwan, Taipei, Taiwan, (2)Life Sciences, National Cheng Kung University, Tainan, Taiwan

The most influential hypothesis regarding species geographic limits suggests that inter-specific competition play a more important role in determining the range limit at benign and species-rich environments, such as lower latitude and elevation; whereas abiotic factors will be more important in constraining the distribution of species in harsh and species-poor environments, such as high latitude and elevation. However, empirical supports for this hypothesis have been sparse and equivocal. The importance of species interactions in determining species fitness can vary with population density and environmental condition. However, to which extent these biotic and abiotic factors constraining geographic range limit remains unclear. Here we experimentally test the mechanisms underlying elevational range limits of burying beetles (Nicrophorus nepalensis) by transplantation and manipulating factors associated with strength of species interaction.


We found that interspecific competition was the major driver of both upper and lower range boundaries of burying beetles. At the cool-edge upper limit, where the population densities of both species are low, the time required for locating the breeding resource (carcass) determines their breeding success, representing typical exploitation competition. At warm-edge lower limit, population densities of both species are high, both species detect and arrive at the carcasses rapidly, and the burying beetles have to exclude the maggots from the carcasses to breed successfully. The process represents typical interference competition. Our study demonstrates that the transitions from the interference to exploitative competition set the lower to upper range limits of species. The significance of species interaction, in combination with widely observed species redistribution under climate change, suggests that experimental macroecology in understanding mechanisms of species range limits is urgently needed.