Avicennia germinans leaf traits in degraded, restored, and natural mangrove ecosystems of Guyana

Mangrove leaves have unique features that enable them to cope with shifting environmental conditions while preserving their general functionality and efficiency. We examined the morphological characteristics and chlorophyll content (spectroscopically) of 600 mature Avicennia germinans leaves selected from 30 trees located in one degraded, one restored, and one natural mangrove ecosystem along Guyana's coastline. Systematic sampling was carried out using the closest individual sampling method in the wet and dry seasons. We hypothesized that both habitat type and seasonality influence the leaf traits and chlorophyll content of A. germinans. Our findings showed that A. germinans leaves are mesophyllous, and traits such as leaf perimeter, area, length, width, dry mass, wet mass, turgid mass, leaf-specific area, and relative water content showed fluctuations in ecosystems (one-way ANOVA, p < .05) as well as seasonally (paired t-test, p < .05). Substantial, positive correlations (p < .05, R > .75) were also established for over 10 leaf parameters in both seasons while PCA and multiple regression analyses further confirmed the strong relationships between leaf morphological features and their respective locations. Changes in chlorophyll concentration were most noticeable in the degraded ecosystem while variations in leaf traits were more pronounced in the restored mangrove area. This may be due to the various disturbances found in each ecosystem coupled with fluctuations in the seasons. Our results demonstrate that mangroves, to some extent, alter their plant structures to cope with environmental stressors present in the various ecosystems they thrive in to maintain their survival.