A new analytical framework for Maxent species distribution models unveils complex spatiotemporal suitability patterns for two migratory seedeaters (Aves: Sporophila) of conservation concern

DIAS RA; MARCON AP; KAPPES BB; AZPIROZ AB; BARBOSA FG; BENCKE GA; CLAY R; DI GIACOMO AS; FONTANA CS; REPENNING M; SARQUIS, JA; ARETA JI

ECOLOGICAL INFORMATICS

ELSEVIER SCIENCE BV

Año: 2023 vol. 77

1574-9541

Maxent species distribution models (SDMs) for rare, migratory taxa can be hindered by methodological andanalytical issues. To overcome these problems, we developed an analytical framework to build SDMs for keystages of the annual lifecycle of the Marsh Seedeater and the Black-bellied Seedeater, two Neotropical grasslandbird species of conservation concern. Occurrence data were compiled from multiple sources and ten environ-mental variables were used as predictors. We built SDMs with different spatial partitions, feature classes, andregularization multipliers, and devised a procedure to select models with high discrimination ability, lowoverfitting, statistically significant performance metrics, and high biological realism. From a total of 992 SDMs,22 fully met the selection criteria for both species. These selected SDMs were equally or less overfit than non-selected ones and were mostly trained with the checkerboard 2 and n − 1 jackknife partitions. For eachmodeling scenario, we projected and interpreted composite models that emphasized areas of both consensus anddivergence across individual predictions, rather than choosing a single model from the set of final SDMs. In thebreeding season, areas of highest suitability occurred in restricted, disjunct sectors of the Campos and Pampasgrasslands for the Marsh Seedeater and the highland grasslands of southern Brazil for the Black-bellied Seedeater.In the winter, high suitability for the Marsh Seedeater occurred in the western and northern Cerrado and thePantanal, while in the spring migration, high suitability for the Black-bellied Seedeater was mostly concentratedin the southeastern portion of the Cerrado. The restricted breeding distribution of the Black-bellied Seedeatersuggests that its conservation status should be reviewed. Both species shift their climatic niches and track theirhabitats throughout the year, responding to a few topographic, land-use, and climatic variables that representdifferent niche components. By addressing major modeling issues in a three-step model selection procedure, wewere able to project precise and biologically interpretable SDMs with the level of complexity required for eachmodeling scenario. Our framework is readily replicable and can be used to unravel intricate spatial suitabilitypatterns of organisms whose distribution undergoes temporal shifts throughout the year.