Local Drivers Associated to Temporal Spectral Response of Chlorophyll-a in Mangrove Leaves

Blanca Castellanos-Basto,Érick Bataller,Jorge Herrera-Silveira,Rodolfo Rioja-Nieto

doi:10.3390/su13094636

Abstract

The pigment content in leaves has commonly been used to characterize vegetation condition. However, few studies have assessed temporal changes of local biotic and abiotic factors on leaf pigments. Here, we evaluated the effect of local environmental variables and tree structural characteristics, in the chlorophyll-a leaf concentration (Chl-a) associated with temporal change in two mangrove species. Rhizophora mangle (R. mangle) and Avicennia germinans (A. germinans) trees of a fringe mangrove forest (FMF) and lower basin mangrove forest (BMF) were visited over a period of one year, to obtain radiometric readings at leaf level to estimate Chl-a. Measurements on tree characteristics included diameter at breast height (DBH), basal area (BA), and maximum height (H). Environmental variables included soil interstitial water temperature (Ti), salinity (Si), and dissolved oxygen (Oi), flood level (fL), ambient temperature (Tamb), and relative humidity (Hrel). Generalized linear models and covariance analysis showed that the variation of Chl-a is mainly influenced by the species, the interaction between species and mangrove forest type, DBH, seasonality and its influence on the species, soil conditions, and fL. Studies to assess spatial and temporal change on mangrove forests using the spectral characteristics of the trees should also consider the temporal variation of leave chlorophyll-a concentration.

Highlights

Mangrove forests (MFs) are of great ecological and economic importance to humans, especially from coastal communities [1]; they are highly productive [2,3,4], generate large amounts of nutrients and organic matter that subsequently contributes to soil formation and coastal erosion control [5,6], they are ecosystems that provide food, shelter and breeding to a wide variety of flora and fauna including commercial species, and they are key to reductions in the greenhouse gases (GHG) effect
The results are consistent with various authors [17,35,45], who explained that the variability in Chl-a between R. mangle and A. germinans is due to the relationship to their diameter at breast height (DBH), basal area (BA), and the development of the tissue of their leaves according to the species, the presence of nearby water sources, local characteristics, and seasons
Our results showed that remote sensing methods can be used at smaller scales, such as leaf level, to assess the physiological characteristics at the tree level considering changes in species and MF type

Summary

Introduction

Mangrove forests (MFs) are of great ecological and economic importance to humans, especially from coastal communities [1]; they are highly productive [2,3,4], generate large amounts of nutrients and organic matter that subsequently contributes to soil formation and coastal erosion control [5,6], they are ecosystems that provide food, shelter and breeding to a wide variety of flora and fauna including commercial species, and they are key to reductions in the greenhouse gases (GHG) effect. A floodable soil promotes physical and chemical conditions that influence soil anaerobiosis, the accumulation of organic matter in sediments, and the availability of salts, nutrients, and oxygen [13]

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