Habitats antropogênicos direcionam traços funcionais e herbivoria na flora urbana espontânea neotropical

Abstract

Urbanization is among the main drivers of global change today. Urban environmental filters directly affect the vegetation present in cities. However, the structural factors that drive the selection of plant traits, the change in plant-insect interactions and favor non-native species in cities are still poorly understood, particularly in neotropical regions. Thus, in the present work we investigated how the intensity of urbanization and anthropogenic habitats affected species richness, cover, composition, functional traits and foliar damage in native and non-native plants that establish spontaneously in cities. We sampled landscapes classified into three classes of urbanization intensity, defined by the percentage of gray area (construction and pavement): low (25-45%), moderate (50-70%) and high urbanization (>75%); for two habitats (sidewalk and vacant lot), in the urban perimeter of Itajubá, Minas Gerais. The functional traits measured were height, specific leaf area (SLA), life form, dispersal syndrome and leaf damage (herbivory, pathogens and trampling). Richness, coverage, functional attributes, and leaf damage data (dependent variables) were analyzed using generalized linear models (GLM), with percentage of gray area and habitat type as independent variables. The species compositions were compared with non-metric multidimensional scaling (NMDS). In the city, we collected 88 plant species, 38 natives and 50 non-natives, showing a high occurrence of non-native species (64.6%). The type of habitat had a greater influence on the plant community than the urbanization intensity. Species richness decreased with increasing gray area, vegetation cover was higher in vacant lots compared with sidewalks, and species compositions were significantly different between sidewalks and lots. For the functional traits, community height was higher in lots, SLA increased with the percentage of gray area, therophyte life form was more present in sidewalks, whereas geophyte, chamaephyte and hemicryptophyte in lots. Autochoric dispersion syndromes occurred with higher frequency on sidewalks and zoochorous on lots. The percentage of herbivory was also higher in lots. Few traits varied along the urbanization classes ans vacant lots encompassed a greater variation of community traits, evidencing the importance of this ruderal habitat for urban biodiversity.