Urban living influences the reproductive success of Darwin’s finches in the Galápagos Islands

Abstract

<jats:title>Abstract</jats:title><jats:p>Urbanization is expanding worldwide and can have major consequences for organisms. For example, urban areas can contain novel stressors that reduce the fitness of animals but may also have benefits, such as consistent human food availability. These trade-offs are particularly important in dynamic environments with unreliable annual natural food availability, such as in the Galápagos Islands. In our study, we compared the reproductive success of small ground finches (<jats:italic>Geospiza fuliginosa</jats:italic>; a species of Darwin’s finch) in an urban and non-urban area during a dry year (i.e. one with low natural resource availability) on San Cristóbal Island in the Galápagos Islands. We also documented the abundance of anthropogenic-related material, such as human hair and plastic, in finch nests and determined whether incorporating these materials into the nest led to entanglement- or ingestion-related mortalities. Overall, urban finches built more nests, laid more eggs, and produced more nestlings than non-urban finches. However, every nest in the urban area contained anthropogenic-related material, which resulted in four mortalities (out of 17 nests with nestlings) due to entanglement or ingestion. Non-urban nests did not contain any anthropogenic-related material. Our study showed that urban living has trade-offs: urban birds have overall higher reproductive success than non-urban birds, but urban birds can also suffer a negative consequence by using anthropogenic-related material in their nests. These results suggest that despite the potential cost of urban living, finches benefit overall from urban living and urbanization may buffer the effects of limited resource availability in the Galápagos Islands.</jats:p>

Applied ecoimmunology: using immunological tools to improve conservation efforts in a changing world

“…Darwin’s finches have also had to deal with habitat change resulting from the rising human resident and tourist population in the Galapagos ( Salinas-de-León et al , 2020 ). Urban finches can experience an increase in fitness compared to non-urban finches ( Harvey et al , 2021 ), which might be related to increased food availability ( De León et al , 2019 ) or changes in behaviour ( Gotanda, 2020 ) or the gut microbiota ( Knutie et al , 2019 ). This habitat change could improve finch immunity to parasites by providing the necessary energetic resources to invest in an immune response, as found in other bird-parasite systems ( Knutie, 2020 ).…”

“…This habitat change could improve finch immunity to parasites by providing the necessary energetic resources to invest in an immune response, as found in other bird-parasite systems ( Knutie, 2020 ). Preliminary evidence suggests that urban finches have higher nesting success than non-urban finches, which is likely related to their improved resistance to avian vampire flies ( Harvey et al , 2021 ). However, human-altered habitats can have varying effects on finch-parasite interactions.…”

Phylogeography of the Japanese greater horseshoe bat Rhinolophus nippon (Mammalia: Chiroptera) in Northeast Asia: New insight into the monophyly of the Japanese populations

“…It is distributed worldwide, including on various islands, but not in the polar regions. Evolutionary biological studies of organisms on islands—island biological studies—have focused on birds that evolved dramatically as the result of isolation and adaptive radiation to the island environment as represented by Darwin's finches (Burns et al, 2002 ; Harvey et al, 2021 ; Lack, 1945 ; Lamichhaney et al, 2016 ; Sato et al, 1999 ; Weir et al, 2009 ). Although bats are regular members of island ecosystems and adapted to island environments, they have been rarely focused in island biological research.…”