Modelagem de distribuição de espécies para aves campestres ameaçadas de extinção

Abstract

The Wallacean Shortfall, in which the distribution of organisms is not completely known, hampers the conservation of threatened species of restrict distribution and/or migratory. Long-term climatic changes, natural or anthropic, allied to habitat alteration, pressure biodiversity to adapt to new conditions, especially migratory species, which use different places in distinct times. Species Distribution Modelling for past, present and future distributions and occupancy modelling, which estimates when a species occupies a given location, might help to reduce the Wallacean Shortfall by using occurrences from literature, museum and citizen science. The goal of the first article was to clarify in which way the Marsh Seedeater, an endangered migratory grassland bird whose breeding and specially wintering areas are mostly unknown, is distributed throughout the year and to infer possible migratory routes by using monthly occupancy models for 11 sites. The second article was with the same species and aimed in modelling the potential distribution for its breeding and wintering grounds. The third article objectified to model the potential past (Last Glacial Maximum and Middle Holocene), present and future (rcp4.5, rcp6.0 and rcp8.5 scenarios for 2070) distributions for the Saffron-cowled Blackbird, an endangered grassland bird. For both articles, the potential distribution models were made in MaxEnt using bioclimatic variables from the WorldClim database. The results for the Marsh Seedeater articles showed that 1) in October-March it breeds from the northeast of Argentina to the south of Uruguay, 2) it migrates along the Paraná and Paraguay Rivers to the Central Brazil between February-April 3) tracking similar temperatures between the breeding and wintering grounds, 3) winters during May-August in the Cerrado of mid-western Brazil, 5) part of the population displaces eastwards in the Brazilian Cerrado (SeptemberNovember) and 6) apparenty returns west (October-November), from where they migrate south. The results of the third article show that 1) during the Last Glacial Maximum, the Saffron-cowled Blackbird occupied areas in the north of its current distribution (west and east of Rio Grande do Sul in Brazil, and Misiones in Paraguay) due to the lower temperatures in the south, 2) in the Middle Holocene, with a warmer climate, its distribution expanded south (south of Rio Grande do Sul, coast of Uruguay and the north coast of Buenos Aires), 3) currently, it inhabits the same areas in a more restricted manner, and 4) in all future scenarios, the species will lose suitable areas, especially in the south. Future conservation actions for both species should focus on the areas pointed as suitable. New modelling approaches are encouraged as new occurrences become available, as well as encouraging more citizen science to obtain more information for places with a few records.