Landscape structure influences the spatial distribution of urban bird attractiveness

Context

Landscape change affects biological diversity and the distribution of species traits related to spiritual, educational, and recreational benefits people derive from nature. These traits are associated with color, song and behavioral characteristics that influence people's perceptions of how attractive an assemblage is. However, the environmental variables that affect the spatial distribution of traits related to the attractiveness of biological diversity remain unexplored.

Objectives

We tested how landscape structure influences patterns of perceived bird attractiveness (trait diversity associated with colorfulness, behavioral and song categories) across an urbanization gradient.

Methods

We used data from standardized surveys of birds and landscapes within 42 landscape units of 1km² across the city of Brisbane in eastern Australia. We used structural equation modeling to test effects of landscape composition (built infrastructure, percentage of tree cover) and landscape configuration (fragmentation of tree cover) on mean bird community attractiveness. Relationships between individual traits and landscape structure were analyzed using multinomial logistic regression models.

Results

Our analysis across 82 bird species shows that the relative amount of built infrastructure in a landscape interacts with fragmentation to reduce the overall attractiveness of the landscape’s bird assemblage. However, built areas can exhibit high overall bird attractiveness where there is (1) reduced fragmentation and (2) increased diversity of vegetation structure that provides key habitats for many colorful species with a high diversity of calls. Relationships between bird attractiveness and landscape structure change when they are analyzed at the guild level (insectivores vs frugivores/nectarivores). In addition, body size moderates the effects of landscape structure on song complexity, personality, and color.

Conclusions

Small bodied, colorful and melodious species are negatively affected by built infrastructure and fragmentation. By learning how habitat loss and fragmentation affect the distribution of species-rich, attractive bird assemblages, our findings can inform how urban landscapes might be structured to increase people’s connection with nature.