COS 17-8
Tropical montane tree seedlings’s response to current and novel temperature and precipitation
Tropical mountains are regions of high biological diversity associated with different climate-elevation zones. These areas are projected to experience novel climates with climate change during this century. Models assume that tropical montane biota are intolerant of climate conditions different than they currently experience today. Consequently, these areas are projected to experience high rates of local extinctions with climate change. In this study, we test this assumption of biota’s intolerance of novel climatic factors. We expose, in shadehouse conditions, two species (Quercus insignis and Viburnum costaricanum) of neotropical tree seedlings from montane Costa Rican forests to elevated soil temperature and novel precipitation conditions in order to understand the role of these abiotic factors on the growth and survivorship of these species.
Results/Conclusions
In this study, elevated soil temperatures resulted in a drier soil for the dry season soil moisture treatment than did ambient temperature (p>.05), suggesting that dry season in a warmer climate maybe more intense than in a moderate climate. During the study period, seedlings’ growth was not influenced by soil temperature for these two species (p>.05). However, soil moisture affected growth with more moisture resulting in more growth (p=.01). For Quercus, photosynthesis increased with temperature (p<..05) and didn’t vary with soil moisture (p=.1). These results suggest that montane tree species distribution may not only track temperature as currently modeled for projected distribution studies and that soil moisture may also be key factor determining current and future climate-elevation species distributions, although the relationship between tree growth and soil moisture will need further investigation.