Human land-uses drive assemblage taxonomic & functional diversities
Despite considering environmental and climate-related biodiversity predictors, intensive human land use was a key driver, accounting for 83%, 66% and 83% of the explained variance in taxonomic richness for fish, arthropod, and macrophyte, respectively (Figure 2). Intensive human land use also accounted for 74%, 36%, and 26% of the explained variance in functional diversity for fish, arthropods, and macrophytes (Figure 2). In particular, agriculture, pasture, and urbanization were significantly and negatively related with taxonomic richness and functional diversity of the three assemblages (Figure 3a, Table S6). However, land-use types had contrasting effects on diversity components of fish, arthropod and macrophyte. For instance, agriculture and urbanization were most strongly associated with fish taxonomic richness, whereas pasture and urbanization were most strongly associated with arthropod and macrophyte taxonomic richness (Figure 3b). Similarly, agriculture, pasture, and urbanization were most strongly associated with fish functional diversity, whereas urbanization was most strongly associated with functional diversity of arthropods, and agriculture was most strongly associated with functional diversity of macrophytes (Figure 3c).
Intensive human land use was also important in explaining the diversity of the three trait categories (Table S7). Human land-use accounted for 43%, 24%, and 39% of the explained variance for recruitment and life-history of fish, arthropod, and macrophyte respectively (Figure 4). Similarly, human land-use explained 60%, 60%, and 26% of the variance in diversity of resource and habitat-use for fish, arthropod, and macrophyte (Figure 4). Lastly, human land-use explained 34%, 20% and 43% of the variance in diversity of body size for fish, arthropod, and macrophyte (Figure 4). In general, agriculture and urbanization were negatively associated with diversity of recruitment and life-history, resource and habitat-use, and body size of three assemblages. Afforestation was positively related with diversity of resource and habitat-use of fish and arthropods (Figure 5a). Diversities of trait categories of fish, arthropod, and macrophyte were also significantly related to different land-use types (Figure 5b-d).