Influence of habitat type and distance from source area on bird taxonomic and functional diversity in a Neotropical megacity

Abstract

The Neotropical region has been subjected to massive urbanization, which poses high risks for some global biodiversity hotspots and losses of ecosystem functions and services. In this study, we investigate how distance from large patches of native forests (source areas) and vegetation (green)/and infrastructure (gray) characteristics affect bird species richness and functional diversity in São Paulo megacity, southeastern Brazil. We analyzed the effects of source areas and green/ gray characteristics on species richness and functional diversity (richness, evenness, and divergence) indices. We detected 231 bird species, and our data confirmed our predictions: (1) bird species richness in urbanized habitats was found to be (~ 50-85%) lower than in source habitats; (2) species richness and trait composition significantly decreased as the distance from the source area increased, while functional richness was not affected by this metric; and (3) shrub and herbaceous covers and maximum height of trees were positively correlated with species richness and unique functional traits regarding habitat, diet, foraging and nesting strata and dispersal ability of birds in the forest-urban matrix. The number of buildings was negatively correlated with bird species richness and functional richness. Maximum height of buildings caused dramatic declines in functional evenness. Functional divergence was notably lower in sites with high shrub cover. Our study stresses the complexity of vegetation embedded in large Neotropical urban settlements and the need to maintain large protected areas surrounding megacities to mitigate the impacts of urbanization on birds.

Bird Communities in Coastal Areas. Effects of Anthropogenic Influences and Distance From the Coast

“…And urban dwellers, which can vary from having viable population in both natural and developed areas and persist in urbanized landscapes independently of natural areas, to being dependent on developed areas for survival (Fischer et al, 2015;González-Lagos and Quesada, 2017). Moreover, there are many studies that consider urban gradients incorporating the surroundings of the cities (e.g., Clergeau et al, 1998;Crooks et al, 2004;Melo et al, 2021). For bird assemblages, evidence shows that local habitat characteristics are more important than surrounding landscapes (Clergeau et al, 2001;Evans et al, 2009).…”

Increase in size and shrub cover improves bird functional diversity in Neotropical urban green spaces

“…an increase in the area of urban green spaces can improve functional richness of all bird guilds similar to the positive relationship among species richness and size area (Beninde et al, 2015; Fernández‐Juricic & Jokimäki, 2001) due to the increase in likelihood of a species' addition with a unique functional trait in the community (Melo et al, 2022). Vegetation characteristics and proximity to waterbodies may increase functional richness of target guilds (i.e.…”

“…The remaining green spaces vary from small‐ to large‐sized areas (1 to >10 000 ha). The majority is represented by small and isolated urban parks and squares (Barbosa et al, 2020; Melo et al, 2022). Serra do Mar and Serra da Cantareira State Parks are the largest and most protected areas located at the urban fringe of São Paulo megacity.…”

“…number of pedestrians, cats, dogs, vehicles, and glass panes) may affect bird functional traits, represented by shifts in functional richness. As these last variables may lead to contrasting responses about the abundance of distinct bird guilds, we also predict that they may reduce functional evenness and functional divergence of insectivores, frugivores‐nectarivores, and migrants, as well as increase functional evenness and functional divergence of residents, thus affecting total bird community due to the presence of several abundant birds with similar functional traits (Melo et al, 2022).…”

“…Environmental changes are known to affect bird functional traits, leading to failures in ecosystem functions (Mason et al, 2005; Palacio et al, 2018) and services (Sekercioǧlu et al, 2004) performed by such birds. There are several studies in the literature focusing on bird communities in urban settlements (Beninde et al, 2015; Campos‐Silva & Piratelli, 2020; Chace & Walsh, 2006; Leveau et al, 2019; Marzluff, 2017; Melo et al, 2022; Murgui & Hedblom, 2017; Sol et al, 2014, 2017). It was found that avian species play an important role in socio‐economic and cultural aspects of human life (Belaire et al, 2015; Sekercioǧlu et al, 2004; Tratalos et al, 2007), as they are surrogate markers for the bioindication of environmental quality (Parker III et al, 1996) and faunal integrity (Amâncio et al, 2008; MacGregor‐Fors et al, 2010; Morelli et al, 2017), including several well‐accepted charismatic species, which are fundamental to the biological conservation in urban ecosystems (Piratelli et al, 2017).…”