Padrões espaço-temporais de distribuição de littoraria angulifera (Lamarck, 1822) (Gastropoda: Littorinidae): aspectos ecofisiológicos e características populacionais em um manguezal do semiárido nordestino brasileiro

Abstract

Mangroves are tropical coastal ecosystems which have a great ecological and economic importance, influencing the distribution of many invertebrate species. Among these, Littoraria angulifera stands out as an essential gastropod in the mangrove ecosystem and an excellent model for studying in the intertidal zone due to its abundance, ease of collection, identification, and environmental adaptability. This study analyzed the distribution of L. angulifera and the interaction with variations in temperature, salinity, and mangrove structure in the Pacoti River estuary, Eusébio, CE. In the first chapter, 12 monthly collections were conducted from September 2020 to September 2021, focusing on the ecophysiological responses of this species along spatial-temporal gradients. The second chapter focused on the spatial distribution and population structure of L. angulifera in different regions of the estuary during the rainy, transition, and dry periods in 2022. The results showed larger and heavier shells near the water, possibly due to better availability of food and water retention capacity. The internal temperature of the animals increased with distance from the river, indicating less protection against external factors in the edge zone, where there is more thermal stress. Internal oxygen saturation also varied, with higher values closer to the water. The density of organisms was significantly influenced by seasonality and proximity to the waterline, varying according to the position on the trees and the seasons. These results emphasize the importance of considering environmental gradients and micro-habitats when investigating the ecology of L. angulifera. Proximity to water seems to create a more favorable microclimate, with less water stress and greater food availability. It is concluded that L. angulifera is an effective indicator of environmental changes, responding distinctly to different environmental conditions.