Physiological response strategies of pioneer endemic species

Introduction: Wind erosion and sand burial are recurrent but physically distinct aeolian disturbances in semi-arid dune systems. We investigated how Methods: Seedlings were subjected to five simulated wind-erosion levels (0, 2, 4, 6, and 8 cm) and five sand-burial levels (0, 1.7, 3.3, 5.0, and 6.7 cm). Chlorophyll, proline, soluble sugar, malondialdehyde (MDA), peroxidase (POD), and superoxide dismutase (SOD) were quantified. Treatment effects were evaluated using two-way ANOVA, PCA of standardized variables, disturbance-specific Spearman correlations, and an exploratory path analysis. Results: Disturbance type, relative disturbance level, and their interaction affected all six physiological traits, and PCA separated the two-treatment series in multivariate space. Under sand burial, chlorophyll, proline, and soluble sugar showed positive within-treatment covariation after Spearman correlations. Under simulated wind erosion, POD and SOD covaried positively, whereas MDA was not significantly correlated with either antioxidant enzyme; chlorophyll-proline and soluble sugar-MDA associations also remained significant after correction. The exploratory path model had limited overall fit and was used only to summarize statistical associations, not to establish causal physiological mechanisms. Discussion: Under the controlled conditions of this seedling experiment, the two isolated treatments were associated with different physiological response and covariation patterns. These results provide testable hypotheses about disturbance-specific seedling responses rather than evidence of switchable association, population-level persistence, or restoration performance. Validation is required under field conditions, across additional life stages, and with pulsed and combined erosion-burial events.