Browsing by Autor "Alain Hambuckers"

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Artificial Green Corridors in an Andean City as Effective Support of Avian Diversity
(Multidisciplinary Digital Publishing Institute, 2023) Alain Hambuckers; Johann Delcourt; Bryan Leborgne; Jennifer R. A. Cahill
Ensuring connectivity in the countryside and cities is a key element of nature protection, allowing genetic fluxes between populations in fragmented ecosystems. We tested the hypothesis that artificial green corridors are effective for birds in the city of Cochabamba (Bolivia). We compared the following aspects of natural corridors, with generally preserved vegetation, to those of artificial corridors, constituting parks and gardens in a matrix of streets densely planted with trees: species abundance and richness, functional diversity, and the traits of bird communities. We used canonical redundancy analysis to relate species abundance to the corridor type, noise, tree vegetation structure, richness, and functional diversity. We also tested the explanatory factors for relationships with bird species richness, functional diversity, and traits. We found that most species were shared between the corridor types; the corridor type, nevertheless, had significant effects, with bird species in the green corridors being more common and heavier and having a lower beak depth/mass. By contrast, noise-reflecting urbanization deeply affected all of the studied traits, indicating large shifts in species composition. In conclusion, green corridors seem reliable enough to maintain birds at a level almost comparable to that in linear corridors, but noise is a limiting factor for efficiency for both types.
Predicting the Future Distribution of Ara rubrogenys, an Endemic Endangered Bird Species of the Andes, Taking into Account Trophic Interactions
(Multidisciplinary Digital Publishing Institute, 2021) Alain Hambuckers; Simon de Harenne; Eberth Rocha Ledezma; Lilian Zúñiga Zeballos; Louis François
Species distribution models (SDMs) are commonly used with climate only to predict animal distribution changes. This approach however neglects the evolution of other components of the niche, like food resource availability. SDMs are also commonly used with plants. This also suffers limitations, notably an inability to capture the fertilizing effect of the rising CO2 concentration strengthening resilience to water stress. Alternatively, process-based dynamic vegetation models (DVMs) respond to CO2 concentration. To test the impact of the plant modelling method to model plant resources of animals, we studied the distribution of a Bolivian macaw, assuming that, under future climate, DVMs produce more conservative results than SDMs. We modelled the bird with an SDM driven by climate. For the plant, we used SDMs or a DVM. Under future climates, the macaw SDM showed increased probabilities of presence over the area of distribution and connected range extensions. For plants, SDMs did not forecast overall response. By contrast, the DVM produced increases of productivity, occupancy and diversity, also towards higher altitudes. The results offered positive perspectives for the macaw, more optimistic with the DVM than with the SDMs, than initially assumed. Nevertheless, major common threats remain, challenging the short-term survival of the macaw.