Ecological Archives A025-021-A1
Hillary S. Young, Douglas J. McCauley, Rodolfo Dirzo, Jacob R. Goheen, Bernard Agwanda, Cara Brook, Erik Otárola-Castillo, Adam W, Ferguson, Stephen N. Kinyua, Molly M. McDonough, Todd M. Palmer, Robert M. Pringle, Truman P. Young, and Kristofer M. Helgen. 2015. Context-dependent effects of large-wildlife declines on small mammal communities in central Kenya. Ecological Applications 25:348–360. http://dx.doi.org/10.1890/14-0995.1
Appendix A. Appropriateness of plot sizes used.
Most of this research was conducted using 1 ha sites within larger plots of similar land-use type. However, for the UHURU exclosure experiments, plots were only 1 ha, and we only sampled the inner 0.36 ha in order to conservatively avoid any edge effects in community composition or abundance of small mammals. While larger plots are nearly always preferable, these exclosures are scaled appropriately to the ecological responses of small mammals measured and are consistent with plot sizes of other small mammal survey work (e.g., Heske et al 1994).
Data from more than five years of small trapping (~100,000 trap nights, from bimonthly surveys) in UHURU (Goheen et al 2013, J. Goheen, personal communication) has shown that animals never moved between plots within 4 day trapping bouts and only rarely (3 total instances observed) between trapping bouts. The individual home range sizes of larger species are between 100 and 299 m² and are thus likely well contained within the 1000 m² plot we are sampling. Smaller animals (for which home ranges were not surveyed due to difficulty of maintaining marks between capture bouts, e.g., Mus spp.) likely have even smaller home ranges. Thus, while animals certainly can and do have the capacity to move outside this experiment they do this very infrequently and never within a trapping bout. Consistent with this, long-term trapping in UHURU documents similar strong and consistent numerical increases in small mammal capture rates inside as compared to outside of exclosures as reported in this study (Goheen et al. 2013).
Literature cited
Goheen, J. R., T. M. Palmer, G. K. Charles, K. M. Helgen, S. N. Kinyua, J. E. Maclean, H. S. Young, and R. M. Pringle. 2013. Piecewise disassembly of a large-herbivore community across a rainfall gradient: the UHURU experiment. PLoS ONE, 8:e55192.
Heske, E. J., J. H. Brown, and S. Mistry. 1994. Long-term experimental study of a Chihuahuan Desert rodent community: 13 years of competition. Ecology 75:438–445