Determinants of high mountain plant diversity in the Chilean Andes: From regional to local spatial scales

Abstract

Mountains are considered excellent natural laboratories for studying the determinants of plant diversity at contrasting spatial scales. To gain insights into how plant diversity is structured at different spatial scales, we surveyed high mountain plant communities in the Chilean Andes where man-driven perturbations are rare. This was done along elevational gradients located at different latitudes taking into account factors that act at fine scales, including abiotic (potential solar radiation and soil quality) and biotic (species interactions) factors, and considering multiple spatial scales. Species richness, inverse of Simpson’s concentration (Dequiv), beta-diversity and plant cover were estimated using the percentage of cover per species recorded in 34 sites in the different regions with contrasted climates. Overall, plant species richness, Dequiv and plant cover were lower in sites located at higher latitudes. We found a unimodal relationship between species richness and elevation and this pattern was constant independently of the regional climatic conditions. Soil quality decreased the beta-diversity among the plots in each massif and increased the richness, the Dequiv and cover. Segregated patterns of species co-occurrence were related to increases in richness, Dequiv and plant cover at finer scales. Our results showed that elevation patterns of alpine plant diversity remained constant along the regions although the mechanisms underlying these diversity patterns may differ among climatic regions. They also suggested that the patterns of plant diversity in alpine ecosystems respond to a series of factors (abiotic and biotic) that act jointly at different spatial scale determining the assemblages of local communities, but their importance can only be assessed using a multi-scale spatial approach.

The role of root community attributes in predicting soil fungal and bacterial community patterns

“…Soil physicochemical analyses were conducted as described by López‐Angulo et al . (2018). Briefly, we analysed four nutrient stocks: soil organic carbon (SOC), total nitrogen (N), available phosphorus (P) and potassium (K); two dynamic variables related to the soil microbial activity such as acid phosphatase and β‐glucosidase enzymatic activities; and several variables such as pH, electrical conductivity, sand, silt and clay contents (Table S1).…”

Spatial autocorrelation signatures of ecological determinants on plant community characteristics in high Andean wetlands

“…This highlights the existence of non-spatially structured physical variations of importance for the development and composition of high Andean wetland plant communities. High Andean landscapes are highly topographically heterogeneous displaying abrupt changes in local edaphic and microclimatic conditions 52,53 , which may lack clear spatial patterns at the resolution and scale of our study. Slope www.nature.com/scientificreports/ and mean annual wind speed, both ecological variables used in this study, are often associated with large local fluctuations and could thus alter plant community characteristics without leaving a specific spatial footprint.…”

Climatic and Ecological Changes in the Subtropical High Andes During the Last 4,500 Years

“…However, it must be taken into account that the taxonomic resolution obtained through pollen is low, and this could influence the results of diversity analysis (Mander and Punyasena, 2014). Some studies in the mountain zone of north-central Chile show that there is lower alpha and beta diversity at higher altitudes, related to climate conditions less favorable for plant development (López-Angulo et al, 2018).…”