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Meiofauna are ubiquitous but poorly-studied components of soft-bottom marine habitats around the world, including mangroves. The dynamic environmental conditions and heterogeneous sediments of mangroves present challenges to understanding the structure of mangrove meiofaunal assemblages at various spatial and temporal scales. In this study, we investigated the meiofaunal assemblage structure of sediments colonised by three mangrove species, namely, Avicennia marina, Rhizophora stylosa and Aegiceras corniculatum , at three locations in subtropical eastern Australia. Spatial and temporal variations were tested by sampling at the three mangrove locations (i.e. Tallebudgera, Currumbin and Terranora) in autumn, with samplings repeated at Tallebudgera at two other times broadly representing during dry/cool winter and wet/hot summer seasons. We examined the variability of the sediment environments within each of the different mangrove species, and investigated how meiofaunal assemblages would respond to the particular changes in their habitats to result in differences in assemblage structure between and within sites. Total meiofaunal density was highest in Tallebudgera and Currumbin and lowest in Terranora (mean density of 424, 393 and 239 ind.10 cm −2 , respectively). In Tallebudgera, the density was higher in winter and summer (mean density of 546 and 530 ind.10 cm −2 , respectively). The meiofaunal assemblage in this study shows a trend and association with the environmental variables. High availability of food proxies such phaeopigments, Chl a or TOC, with moderate tannin content and appropriate habitat structure (sediment particle size, belowground root biomass and/or moisture content provide the best condition for the meiofauna to achieve the highest density. However, given the complex dynamic habitats and the spatial heterogeneity of the mangrove environments across different locations and seasons, no clear generalization could be made regarding the key environmental variables that predominantly shape the meiofaunal assemblages’ structure. [ABSTRACT FROM AUTHOR]

Mangrove rehabilitation programs received much attention in the past decades as a response to widespread global degradation. While the documented successes and failures of mangrove rehabilitation accomplishments were varied, the objective and scheme is common, mainly focused on planting and creating monospecific plantations. This study assessed the structural development and complexity of the large-scale plantations in the central part of Philippines and compared it with the adjacent natural stand as reference. Our study showed that planted forest in both sites had lower structural complexity than the reference natural forest. Between sites, secondary succession in the monospecific plantation in Banacon Island was inhibited as reflected by low regeneration potential, whereas recruitment and colonization of non-planted species was promoted in Olango Island. Even 60 years after the forest was created in Banacon Island, it still lacked the understory of young cohorts which together comprise the regeneration potential that can supposedly add to the structural complexity. Although a potential seed source from adjacent natural forest is available, recruitment and colonization of non-planted species did not progress. MDS analysis of tree density data showed clustering of planted forest from the natural stand. The average SIMPER dissimilarity was 79.9% and the species with highest contributions were R. stylosa (74.6%), S. alba (11.1%) and A. marina (10.6%). Within the natural forest, the same species had the highest dissimilarity contribution, whereas in the planted forest, only R. stylosa contributed the highest dissimilarity. The same trend was also revealed in the MDS ordination analysis of diameter at breast height (DBH). A one-way ANOSIM permutation test of the density and DBH showed a significant difference between the planted and natural forests. Thus, as part of silviculture management intervention, the current practices of mangrove reforestation needs to be reviewed and evaluated to determine the trajectories of its conservation objectives to achieve the best outcome and functionality of the restored habitat. [ABSTRACT FROM AUTHOR]