Precipitation and potential evapotranspiration determine the distribution patterns of threatened plant species in Sichuan Province, China

Abstract

A fundamental goal of ecologists is to determine the large-scale gradients in species richness. The threatened plants are the priority of such studies because of their narrow distribution and confinement to a specific habitat. Studying the distribution patterns of threatened plants is crucial for identifying global conservation prioritization. In this study, the richness pattern of threatened plant species along spatial and elevation gradients in Sichuan Province of China was investigated, considering climatic, habitat-heterogeneity (HHET), geometric constraint and human-induced factors. The species richness pattern was analyzed, and the predictor variables, including mean annual temperature (MAT), mean annual precipitation (MAP), potential evapotranspiration (PET), HHET, and disturbance (DIST), to species richness were linked using the geographical distribution data of threatened species compiled at a spatial resolution of 20 km × 20 km. Generalized linear models and structural equation modelling were used to determine the individual and combined effects of each variable on species richness patterns. Results showed a total of 137 threatened plant species were distributed between 200 and 4800 m.a.s.l. The central region of the province harbors the highest species diversity. MAP and PET profoundly explained the richness pattern. Moreover, the significant role of DIST in the richness patterns of threatened plants was elucidated. These findings could help determine the richness pattern of threatened plant species in other mountainous regions of the world, with consideration of the impact of climate change.

Bioclimatic predictors of forest structure, composition and phenology in the Paraguayan Dry Chaco

“…Factors other than those included in this study that may be affecting diversity and need further study in Dry Chaco forests are potential evapotranspiration (PET) (Trejo & Dirzo 2002), insolation (Balvanera et al 2002) and soil type (Peña-Claros et al 2012). For instance, PET reflects water availability and takes into consideration a variety of factors like solar radiation, temperature and precipitation, all of this factors plus their fluctuations can enhance or decrease the diversity as it had been shown in other ecosystems in China (Li et al 2022), Mexico (Trejo & Dirzo 2002) and Nepal (Bhattarai & Vetaas 2003). Insolation, on the other hand, plays a role on soil water evaporation and disturbance regimes due to drought-related mortality, and the water stress caused by the dry season could be influencing the distribution of species in the Chaco, as it had been observed in other tropical forests (Balvanera et al 2002).…”