Leaf trait spectrum of mangroves: across and within species

Abstract

Abstract Mangroves are widely recognized as one of the most carbon-rich ecosystems. However, the impact of different species, especially slow- and fast-growing ones, on carbon stocks can vary significantly1. These findings have generated a strong interest in understanding the diversity of resource-investment strategies among mangrove species. The global leaf economic spectrum holds the potential for identifying these strategies in mangroves2,3. Nevertheless, it remains unclear whether leaf economic traits of mangrove species exhibit expected coordination patterns. Through the analysis of 36 widely distributed mangrove species, we demonstrate that the cross-species trait spectrums of mangroves encompassing both true mangroves and mangrove associates align with findings from global vegetation analysis2. The distinct strategies between mangrove groups indicated by trait spectrums are consistent with previous observations4. However, the cross-species trait spectrums are not consistently valid in identifying strategies within or between mangrove species. Through conducting a case study, we provide empirical evidence that a fast-growing species (having a greater photosynthetic capacity and tree height) could be positioned towards the slower end of trait spectrums compared with slow-growing species when living in hyper-saline soils. Contrary to the common assumption5,6, the greater mass per leaf area of the fast-growing species is primarily derived from thicker leaves and a higher phosphorus content per leaf area compared with the slow-growing species. These findings suggest that the cross-species trait spectrum may have limitations in accurately identifying resource-investment strategies in plants with thick leaves.