COS 295-4 - Leaf trait coordination spectrums of mangroves: within and across species

Abstract: Mangroves are an important blue carbon community. Understanding the diversity in resource investment strategy among species is cruel to understand the functioning and services they provided. Although the global leaf trait coordination spectrum across species has been assumed to indicate a continued slow-to-fast strategy in resource investment, mangroves are generally excluded from global trait analysis. We assumed that mangroves exhibit similar trait coordination spectrums and expected to use them to identify resource investment strategies within and between species. We are also interested in exploring the potential drivers for trait coordination within and across species. We analyzed the correlation between leaf mass per unit area (LMA) and leaf chemical contents of 36 mangrove species across 11 mangrove sites to examine the trait coordination spectrums within and across species, and then combined with isotopic analysis and photosynthetic measurement to find out the potential drivers according to the least-cost principle. We confirmed that the trait spectrums across mangrove species followed the global patterns, with mangroves tending to adopt conservative strategies. We observed a distinct trait range between mangrove groups (true and minor mangroves) on the trait spectrums, with true mangroves having overall higher LMA and leaf carbon but lower nutrients than minor mangroves, implying an opportunity of using the trait coordination spectrums to classify mangrove groups which have long been debated. Intra-specific trait coordination varied in diverse directions with soil nutrients and salinity. Hyper salinity exerts stronger impacts on trait variation of fast-growing species compared with slow-growing species, resulting in species re-ordering on the trait spectrums. This challenges the use of trait spectrum to compare the resource investment strategy between species. The combined analysis of intrinsic and instant evidence indicates that the primary driver of trait spectrum across species and the variation within species is the capability of nitrogen use for carbon gain of mangrove species. Our findings indicate that the trait coordination spectrum of mangroves is suitable for identifying the resource investment strategies within species but it should be cautious when comparing between species, particularly for those species having contrast strategies.