The Good, the Bad, and the Ugly of Urbanization: Response of a Bird Community in the Neotropical Andes

Abstract

Urbanization constitutes one of the most aggressive drivers of habitat and biodiversity loss worldwide. However, studies focused on determining the response of local biodiversity to urbanization are still scarce, especially in tropical ecosystems. Urban ecosystems are characterized by low biological productivity which in turn leads to a reduction in biodiversity. However, the responses to urbanization should be species dependent. For instance, changes in the availability of resources can favor certain species with specific characteristics. We assessed the effects of the urbanization process on a bird community in a city located in the Tropical Andes of southern Ecuador, a region widely recognized for its diversity and endemism of birds. We selected three independent localities in each of the four levels of the urbanization gradient in the study area (forest, forest-pasture, pasture, and urban). In each locality, we sampled the bird community by visual and auditory surveys along 1 km transects between 2016 and 2017. We recorded a total of 1,257 individuals belonging to 74 bird species. We evaluated if the responses of richness and abundance of birds are dependent on trophic guild and foraging strata. We found a significant decrease in bird species richness and abundance from forest to urban sites. However, the response of birds was dependent on the trophic guild and foraging strata. Granivorous birds showed a positive response associated with the urbanization gradient while insectivorous birds showed a negative response. Insectivorous birds were more abundant in forest sites and decreased in abundance across the urbanization gradient. We found that the proportion of birds using different foraging strata drastically changed along urban gradient. Forest sites exhibited a bird community using a variety of habitats, but the bird community became simpler toward the most urbanized sites. Our findings showed different effects of urbanization on bird communities. The ugly: urbanization leads to a dramatic reduction in the diversity of birds, which is consistent in cities with different characteristics and ecological contexts. On the other hand, the responses of bird guilds to urbanization are species dependent. Some guilds are positively impacted by urbanization and show increases in species richness and abundance while other guilds are negatively impacted.

El Parque Universitario Francisco Vivar Castro: Un refugio clave para las aves de la Hoya de Loja, Ecuador.

“…El conocimiento sobre las aves de la ciudad de Loja y su área de influencia inmediata es aún escueto. Loja cuenta con algunos trabajos divulgativos (Andrade, 2009; Correa-Conde Delgado et al, 2022). Sin embargo, el PUEAR no contaba hasta el momento con ninguna publicación científica que analice la composición de la comunidad de aves que alberga, de ahí que trabajos como el presente complementan el conocimiento sobre las aves y los esfuerzos de conservación que se realizan a nivel local para su permanencia a largo plazo, tema clave y considerado pendiente en la gestión de las áreas protegidas locales de los Andes del sur del país (Astudillo et al, 2015).…”

“…Históricamente, la conversión del bosque nativo en pastizales para ganadería ha sido el cambio más grande y destructivo en el uso de la tierra para los ecosistemas andinos (Thies et al, 2014). Sin embargo, a este cambio del uso del suelo se le suma en la actualidad el creciente desarrollo urbano (Iñiguez-Armijos et al, 2016;Ordóñez-Delgado et al, 2022). La urbanización, entendida como la conversión de hábitats naturales o de producción agropecuaria, por sitios con prevalencia de infraestructura humana (Stein et al, 2000), se considera una de las modalidades más agresivas de alteración y transformación de los ecosistemas naturales y por consiguiente de pérdida de biodiversidad (Lee y Rotenberry, 2015;Banville et al, 2017).…”

Lockdown effects on fear revealed direct and indirect effects of human presence on perceived predation risk

“…components such as climate change and pollution in complex ways (Matesanz et al 2009;Díaz et al, 2022). The effects of Anthropocene on local diversity is generally assumed to be negative (Sol et al 2014;Ibañez-Alamo et al 2017;Morelli et al 2021a), although recent work demonstrates that responses may vary considerably both geographically and for particular species or species groups (Atwell et al, 2012;Díaz et al, 2013;Møller and Díaz 2018a,b;Morelli et al 2020Morelli et al , 2021bOrdóñez-Delgado et al 2022).…”