Influencia da variabilidade climática na dinâmica do banco de sementes do solo em um brejo de altitude na Paraiba

Abstract

The "Brejos de Altitude" constitute Atlantic Forest refugia within the Northeastern Brazilian semiarid region, whose ecological resilience depends on regeneration mechanisms that remain poorly understood over long temporal scales. The investigation of this biological reservoir is justified by its ability to reveal adaptive vegetation strategies, serving as a fundamental basis for developing new management methodologies and for the recovery of degraded areas. This

study analyzed the dynamics and seasonal resilience of the soil seed bank at the Mata do Pau- Ferro State Park (Areia, PB), aiming to fill the gap regarding this ecosystem's response to

climate variability. Monitoring was conducted over consecutive years (2022 to 2024), with soil samples collected in 12 permanent plots before (AEC) and after (DEC) the rainy season, subjected to the seedling emergence method in a greenhouse. Community structure was

evaluated using Shannon’s Diversity (H’) and Pielou’s Evenness (J’) indices, while spatio- temporal and climatic variations were tested via ANOVA, Tukey’s test (p<0.05), and Pearson’s

Correlation. The results evidenced a strong influence of seasonality, where the pre-rain period (AEC) presented significantly higher density and richness than the post-rain period (DEC), confirming precipitation as a trigger for recruitment and the consequent reduction of soil stock. A total of 1,487 individuals were recorded, distributed across 58 taxa and 24 families, with a predominance of Malvaceae, characterizing a community dominated by native pioneer species. Interannual analysis revealed a peak in emergence in 2023 (449 AEC individuals) followed by a reduction in 2024, a behavior that corroborated the Legacy Effect hypothesis, where seed abundance is determined by the accumulated rainfall volume of the previous year. Additionally, a negative correlation was found between insolation and diversity, suggesting that high radiation in the experiment acted as an environmental filter for ombrophilous species. The seed bank acts as a functional storage system, whose dynamics are governed by climatic seasonality and precipitation pulses, ensuring forest resilience in the face of environmental unpredictability.