Nitrogen vs. phosphorus limitation across an ecotonal gradient in a mangrove forest

TL;DR: This study investigates stress causes in Central Red Sea mangroves, finding significant differences in water salinity, temperature, nutrient content, and antioxidant enzyme activities among six study sites, with nutrient limitation and salinity contributing to stress in all sites.

Abstract: Abstract Shrub mangrove (SM) tidal flats are vital ecosystems in tropical and subtropical regions, yet they are threatened by rising sea levels and anthropogenic activities. With their lower canopy height, SMs influence hydro‐sedimentary processes differently from the well‐studied tree mangroves, highlighting the need for a deeper understanding of the stability of the tidal flats they colonize. Here, we analyze hydrodynamic and sediment transport processes over a full spring‐neap tidal cycle on an Aegiceras corniculatum tidal flat in the Nanliu delta China, to explore the bio‐morphodynamic feedback shaping SM tidal flats. Our findings reveal distinct differences in hydrodynamics and sediment transport between the flood and ebb phases, with the flood phase playing a significantly stronger influence. During the flood phase, the interaction between tidal flow and increasing vegetation density landward results in a significant reduction in flow velocity (up to 36%), particularly concentrated at the vegetation fringe. This reduction diminishes sediment transport capacity (up to 80%), leading to a decline in suspended sediment concentration as it moves landward, resulting in localized deposition in front of the densely vegetated area. This process is further supported by the substantial vertical accretion observed over an annual timescale. Our observations reveal that sediment deposition at the front edge of the dense SM zone is associated with a coarsening of surface sediments, which creates favorable conditions for seedling establishment and drives seaward vegetation expansion. These findings highlight the critical role of SMs in coastal ecosystem resilience and the evolution of tidal flats.

TL;DR: Fertilization experiments in nitrogen and phosphorus-limited mangrove forests suggested that N- versus P- limited mangroves do have different thresholds and eutrophication is more likely to cause a shift in nutrient limitation at P-limited Twin Cays than N-limited IRL.

TL;DR: Carbon, nitrogen, phosphorus and potassium analysis showed that they were significantly different in all locations but not between seasons, and the protected mangroves habitat in Johor has siltier and clayey component and can retain more nutrients for the plant growth.

TL;DR: The effects of initial nitrogen and lignin contents of six species of hardwood leaves on their decomposition dynamics were studied at the Hubbard Brook Experimental Forest by inverse linear relationships between the percentage of original mass remaining and the nitrogen concentration in the residual material.

TL;DR: Fundamental differences between the response of woody plants and graminoids to vertebrate herbivory suggest that the dynamics of browsing systems and grazing systems are qualitatively different.

TL;DR: In this paper, the authors analyzed first-year leaf litter decomposition data from 44 locations, ranging from cool temperate sites to humid tropical sites, and found that the control of AET on litter decomposability is partly mediated through an indirect effect of Aet on litter chemistry.