Tag: Biodiversity

How urban habitats shapes bird communities in winter

Posted on by Michely Reis Coimbra

As we discussed in class recently, urbanization often reshapes bird communities, leading to homogenization. Urban areas then become dominated by more adaptable generalists like pigeons and crows. These species usually adjust well to the challenges and opportunities that city life can bring new foods sources, different predator dynamics, and improvised nesting spaces. One other interesting factor that city life can offer to birds, but not often discussed in research, is the food opportunities during winter months. From bird feeders to trash bins, the life of a bird in urban winter is quite different from its natural environment.

To better understand this difference of how urban environments can shape birds’ behavior and distribution during winter, researchers in the Czech Republic (Šálek et al. 2024) investigated bird abundance in 3 small to medium size cities surrounded by agricultural fields, grasslands, and forests. During the 2019-2020 winter they recorded bird abundance and occupancy across various urban habitats. During this time, the authors recorded a total of 4,272 birds of 40 different species. They also found that the most species rich habitats were allotments and old residential areas. In addition, they found that bird feeders were particularly appealing for blue tits and tree sparrows, even in areas with less green areas.

I believe this study highlights important implications for the conservation of urban birds during wintertime, as we learn what types of environments act as refugees during winter, and what can be done for less appealing habitats. Supplementary feeding is often a point of debate in many of our classes, with many arguing that feeders have the potential to increase the bird population beyond its carrying capacity. However, this paper shows the importance of feeders, especially in low quality habitats like industrial areas or new residential developments. Ultimately -and as usual- the use of bird feeders as a conservation tool in urban areas depends on the context of the location. Nonetheless, it is important to keep investigating how birds deal with winter in urban settings, as these answers could help us to shape policies as we learn how to better accommodate bird biodiversity in urban environments all year round.

Source: Šálek, M., Bažant, M., Vrána, J. et al. Urban refuges in winter: the role of habitat characteristics and supplementary feeding in shaping bird occupancy and abundance. Urban Ecosyst 28, 1–10 (2025). https://doi-org.prox.lib.ncsu.edu/10.1007/s11252-024-01632-z

The Luxury Effect: How Black-tailed deer thrive in affluent neighborhoods

Posted on by Michely Reis Coimbra

As cities grow and the world’s population increases, urban landscapes and biodiversity transform.  Many green urban areas have become alternatives for species struggling with habitat loss. As we recently discussed in class, the “Luxury Effect” happens when wealthier neighborhoods have higher biodiversity caused by more green spaces and less human density.

But what does this mean for urban wildlife like the Black-tailed deer? Can green urban areas influence deer behavior, survival, and breeding? That is what the authors of the article “Black-tailed Deer Resource Selection Reveals Some Mechanisms Behind the ‘Luxury Effect’ in Urban Wildlife” investigated in their research.

 The study tracked 20 females with GPS collars to monitor their movements and habitat use in an affluent neighborhood in Victoria, British Columbia, Canada. They found that although wealthy green neighborhoods mean a smaller home range, they significantly impact Black-tailed deer by providing resources such as food and safety from predators. These conditions improve their chances of survival and increase breeding success, resulting in growing deer populations. The authors suggest that deer behavior is adaptable to urban landscapes, and they can alter their foraging habits and spatial use to maximize their resources.

While this research gives us important insights into how urban spaces can support some level of biodiversity, the paper could be improved by expanding this research to include surrounding neighborhoods, genetic material, and GPS collars on males. This data would be helpful to better understand metapopulation dynamics, genetic diversity, and effective wildlife management in urban areas.

Although the results were positive in showing Black-tailed deer succeed in an urban environment, it is important to recognize that the luxury effect often thrives on social inequality, meaning that it is not sustainable. Understanding these dynamics is beneficial, as they give us the chance to explore ways to replicate the biodiversity found in wealthier neighborhoods in less affluent places. By addressing social inequalities and promoting wildlife-friendly urban environments, we can use this knowledge to create more inclusive spaces that support diverse ecosystems for all communities.

Source: Fisher, J. T., Fuller, H. W., Hering, A., Frey, S., & Fisher, A. C. (2024). Black-tailed deer resource selection reveals some mechanisms behind the ‘luxury effect’in urban wildlife. Urban Ecosystems, 27(1), 63-74.