Colombia Resurvey Project: Understanding the past to empower actions that strengthen knowledge and conservation of birds 2021

Camila Gómez, Carlos Daniel Cadena, Andrés M. Cuervo, Jessica Díaz-Cárdenas, Felipe García-Cardona, Nelsy Niño-Rodríguez, Natalia Ocampo-Peñuela, David Ocampo, Glenn Seeholzer, Andrés Sierra-Ricaurte, Juliana Soto-Patiño.

Gustavo Kattan was a visionary scientist who dreamed of repeating historical ornithological expeditions carried out in Colombia by the American Museum of Natural History. Gustavo wanted to study variations in bird assemblages in response to changes in landscape and climate, and thus contribute to bird conservation. Building on Gustavo’s work, the Colombia Resurvey Project is now a reality through an alliance of scientists, local communities, Colombian and international institutions, collecting historical and current data on birds, to understand the ecological, evolutionary and conservation changes that have occurred in a century of transformation. The highly collaborative character of the project allows strengthening and diversifying the information deposited in scientific collections, and by doing so, increases Colombia’s capacity in ornithological research. Furthermore, based on the knowledge of local communities, the project supports participative monitoring initiatives that contribute to promote sustainable economic alternatives in rural areas. Through production of interactive bird maps, a birding tourism business model to be led by local providers, as well as other results from local efforts, we hope to contribute to Colombia’s sustainability and help guarantee the conservation and welfare of birds, their habitats, and the people that protect them.

Gómez et al 2021 – Biota Colombiana. https://doi.org/10.21068/2539200X.984

Change in avian functional fingerprints of a Neotropical montane forest over 100 years as an indicator of ecosystem integrity. 2021

Camila Gómez, Elkin A. Tenorio, Carlos Daniel Cadena

Ecologically relevant traits of organisms in an assemblage determine an ecosystem’s functional fingerprint (i.e., the shape, size, and position of multidimensional trait space). Quantifying changes in functional fingerprints can therefore provide information about the effects of diversity loss or gain through time on ecosystem condition and is a promising approach to monitoring ecological integrity. This, however, is seldom possible owing to limitations in historical surveys and a lack of data on organismal traits, particularly in diverse tropical regions. Using data from detailed bird surveys from four periods across more than a century, and morphological and ecological traits of 233 species, we quantified changes in the avian functional fingerprint of a tropical montane forest in the Andes of Colombia. We found that 78% of the variation in functional space, regardless of period, was described by 3 major axes summarizing body size, dispersal ability (indexed by wing shape), and habitat breadth. Changes in species composition significantly altered the functional fingerprint of the assemblage and functional richness and dispersion decreased 35-60%. Owing to species extirpations and to novel additions to the assemblage, functional space decreased over time, but at least 11% of its volume in the 2010s extended to areas of functional space that were unoccupied in the 1910s . The assemblage now includes fewer large-sized species, more species with greater dispersal ability, and fewer habitat specialists. Extirpated species had high functional uniqueness and distinctiveness, resulting in large reductions in functional richness and dispersion after their loss, which implies important consequences for ecosystem integrity. Conservation efforts aimed at maintaining ecosystem function must move beyond seeking to sustain species numbers to designing complementary strategies for the maintenance of ecological function by identifying and conserving species with traits conferring high vulnerability such as large body size, poor dispersal ability, and greater habitat specialization.

Gomez et al 2021 – Conservation Biology DOI: 10.1111/cobi.13714 

Migratory connectivity then and now: A northward shift in breeding origins of a long distance migratory bird wintering in the tropics. 2021

Camila Gómez, Keith A. Hobson, Nicholas J. Bayly, Kenneth V. Rosenberg, Andrea Morales-Rozo, Paula Cardozo, Carlos Daniel Cadena

Temporal variation in the connectivity of populations of migratory animals has not been widely documented, despite having important repercussions for population ecology and conservation. Because the long-distance movements of migratory animals link ecologically distinct and geographically distant areas of the world, changes in the abundance and migratory patterns of species may reflect differential drivers of demographic trends acting over various spatial scales. Using stable-hydrogen isotope analyses (δ²H) of feathers from historical museum specimens and contemporary samples obtained in the field, we provide evidence for a ~600 km northward shift over 45 years in the breeding origin of a species of songbird of major conservation concern (Blackpoll Warbler, Setophaga striata) wintering in the foothills of the Eastern Andes of Colombia. Our finding mirrors predictions of range shifts for boreal-breeding species under warming climate scenarios and habitat loss in the temperate zone, and underscores likely drivers of widespread declines in populations of migratory birds. Our work also highlights the value of natural history collections to document the effects of global change on biodiversity.

Gómez et al 2021 – Proc. R. Soc. B 288:20210188

Origin and cross-century dynamics of an avian hybrid zone. 2017

Andrea Morales-Rozo, Elkin A. Tenorio, Matthew D. Carling, Carlos Daniel Cadena

Characterizations of the dynamics of hybrid zones in space and time can give insights about traits and processes important in population divergence and speciation. We characterized a hybrid zone between tanagers in the genus Ramphocelus (Aves, Thraupidae) located in southwestern Colombia. We evaluated whether this hybrid zone originated as a result of secondary contact or of primary differentiation, and described its dynamics across time using spatial analyses of molecular, morphological, and coloration data in combination with paleodistribution modeling. Models of potential historical distributions based on climatic data and genetic signatures of demographic expansion suggested that the hybrid zone likely originated following secondary contact between populations that expanded their ranges out of isolated areas in the Quaternary. Concordant patterns of variation in phenotypic characters across the hybrid zone and its narrow extent are suggestive of a tension zone, maintained by a balance between dispersal and selection against hybrids. Estimates of phenotypic cline parameters obtained using specimens collected over nearly a century revealed that, in recent decades, the zone appears to have moved to the east and to higher elevations, and may have become narrower. Genetic variation was not clearly structured along the hybrid zone, but comparisons between historical and contemporary specimens suggested that temporal changes in its genetic makeup may also have occurred. Our data suggest that the hybrid zone likely resulted from secondary contact between populations. The observed changes in the hybrid zone may be a result of sexual selection, asymmetric gene flow, or environmental change.

Morales-Rozo et al 2017 – BMC Evolutionary Biology 17: 257