ABSTRACT Species distribution modeling (SDM) studies of aquatic macrophytes are still attached to methodological paradigms focused on terrestrial plants, such as the use of bioclimatic layers. Our goal was to evaluate the applicability of this paradigm based on a SDM study of Egeria densa, Pontederia crassipes, and Salvinia auriculata in the São Francisco river, Brazil. We compared performances of optimizations of computed models using AUC and TSS with distribution records of these species and bioclimatic layers, or limnological layers generated from the interpolation of data obtained in the field. We calculated models using six algorithms. The models calculated using layers of limnological variables had higher performances than did those calculated using layers of bioclimatic variables, except when the Maximum Entropy Default algorithm was used. We attribute these results to the specificities of the data obtained to develop the limnological layers, such as observations obtained in different habitats of the river and during different hydrologic periods. We conclude that the use of bioclimatic layers, a methodological paradigm traditionally used for SDM of aquatic macrophytes, can be questionable for some situations, such as in investigations at local and regional scales.

Resumo Descrita no ano de 2015, o conhecimento da biogeografia de Pleurophora pulchra é limitado, fato que impossibilitou sua inclusão na primeira avaliação sobre Áreas Prioritárias para Conservação da Flora do Domínio Caatinga (APCFCs) e Unidades de Conservação (UCs). Nesse contexto, propusemos descrever o potencial biogeográfico de P. pulchra na Caatinga através de modelagem de distribuição de espécies (MDE), visando ampliar as discussões sobre APCFCs e UCs. Utilizamos o algoritmo Maxent para computar o modelo final (MDEf), e o teste Binomial para avaliar o desempenho dos mesmos. Constatamos que P. pulchra está ajustada a ambientes de elevada aridez, com baixa precipitação anual, grande sazonalidade na precipitação, temperaturas estáveis nos meses mais frios e solos pouco espessos, variando de imperfeitamente à bem drenados. O MDEf revelou áreas com adequabilidade ambiental predominantemente na depressão sertaneja meridional da Bahia, Pernambuco e Paraíba, além de áreas do planalto da Borborema da Paraíba. As UCs APAs Cariri e Lago de Sobradinho, APCFCs Jatobá e Cariri Paraibano se destacaram pela representatividade da área com adequabilidade ambiental superior a 0.5. O resultado do teste binomial indicou bom desempenho de MDEf (p < 0.001 t =1) e, portanto, reforçou a possibilidade de novos registros de P. pulchra nas áreas supracitadas.

Abstract Having been recently described (2015), knowledge of the biogeography of Pleurophora pulchra is limited, which made its inclusion in the first evaluation of Priority Areas for Conservation of the Flora of the Caatinga Domain (PACFCs) and Conservation Units (CUs) impossible. We describe the biogeographical potential of P. pulchra in the Caatinga using species distribution modeling (SDM), with the aim of broadening discussions about PACFCs and CUs. We used the Maxent algorithm to compute the final model (SDMf), and the Binomial test to evaluate their performance. We found that P. pulchra tends to occur in environments with high aridity, low annual precipitation, intense precipitation seasonality, stable temperatures in the colder months, and thin soils that range from poorly to well drained. The SDMf revealed areas with environmental suitability predominantly in the Southern Sertaneja Depression of the states of Bahia, Pernambuco and Paraíba, as well as areas of the Borborema Plateau in Paraíba. The CUs APAs Cariri and Lago de Sobradinho, and the PACFCs Jatobá and Cariri Paraibano stood out as having environmental suitability values above 0.5. The binomial test exhibited good performance for SDMf (p < 0.001 t =1), reinforcing the possibility of new records of P. pulchra in the aforementioned areas.