Scale‐specific processes shape plant community patterns in subtropical coastal grasslands

Abstract

Processes responsible for shaping community patterns act at specific spatial scales. In this study, we aimed at disentangling the effects of climate, soil and space as drivers of variation in a coastal grassland plant community. We were specifically interested in evaluating the relative influence of those processes at broad and fine spatial scales as well as when considering species groups with good and poor long-distance dispersal capacity. We sampled grassland vegetation at 16 sites distributed along a latitudinal gradient of more than 500 km in subtropical southern Brazil and used variation partitioning procedures to ascertain the relative influence of climatic, edaphic and spatial processes on variation in species composition at different spatial scales, considering the entire community and subsets with only species from the Asteraceae family (good long-distance dispersal) and Poaceae (poor long-distance dispersal). Climatic filters were the most responsible for shaping grassland community composition at the broad scale, while edaphic filters showed higher importance at the fine scale. When not considering the influence of spatial scale, we observed higher influence of climate structured in space. Composition patterns of species with poor long-distance dispersal (Poaceae) were more closely related to spatial variables than those of species with effective dispersal (Asteraceae). Our results stressed the importance of addressing different spatial scales to rightly ascertain the magnitude that different drivers exert on plant community assembly. Dividing the community into groups with different dispersal abilities proved useful for a more detailed understanding of the community assembly processes.

Intraspecific trait variation of grassland species in response to grazing depends on resource acquisition strategy

“…Plant species diversity is estimated to reach 2200 plant species in grasslands in the state of Rio Grande do Sul (Boldrini, 2009). Mean species richness per m 2 at our study sites ranges from 17.2 to 28.6 (Table 1), similar to values found in other studies in the region (Menezes et al, 2016; Andrade et al, 2019). Three sites were located in the Pampa domain (Aceguá, Alegrete and Lavras do Sul) and three in highland grasslands in the Atlantic Forest domain (Cambará do Sul, Jaquirana and São Francisco de Paula; Andrade et al, 2016); the sites thus spanned across two contrasting grassland regions (Overbeck et al, 2007; Andrade et al, 2019).…”

Reference values and drivers of diversity for South Brazilian grassland plant communities

“…It is important to consider the shared effect of space and environment when we discuss the role of environmental drivers shaping grassland community patterns. Both environmental features and space (i.e., dispersal limitation) are potentially filters of community assembly acting at different spatial scales (Menezes et al 2016). Climatic variables are intrinsically spatially structured at broader scales (Bell et al 1993), which makes it difficult to discern between the effects of climate and other spatially structured environmental or biotic factors, such as dispersal limitation, on community composition.…”

“…Climatic variables are intrinsically spatially structured at broader scales (Bell et al 1993), which makes it difficult to discern between the effects of climate and other spatially structured environmental or biotic factors, such as dispersal limitation, on community composition. Soil properties, in contrast, are usually more influent at local spatial scales (Menezes et al 2016).…”