ABSTRACT. The Nee Soon stream drainage in the Central Catchment Nature Reserve is virtually the last remaining fragment of primary freshwater swamp forest in Singapore. The forest type has been poorly studied in the Southeast Asia. The hydrology, water quality, as well as aquatic flora and fauna all have great theoretical and practical significance. The ecology and management of the Nee Soon freshwater swamp forest are reviewed, with remarks on their national, regional and global contexts. This review sets the scene for a three-year integrated conservation and management study completed in 2016.

Questions:How do abiotic conditions, forest structure, as well as taxonomic and functional diversities and composition recover after wind-generated treefalls? Do young and old-growth secondary forests differ in their responses?Location: Mandai region of the Central Catchment Nature Reserve, Singapore, where extensive treefalls occurred during an unusually powerful windstorm in 2011. Southeast Asia.Methods: Soil nitrogen, phosphorous, potassium, canopy cover, leaf litter depth, coarse woody debris, and woody stems ≥1-cm diameter were measured and identified in 10 × 10 m plots. Twenty-six plots were located in treefall areas and 14 plots were located in relatively unaffected areas, with equal numbers in young and old-growth secondary forest types. The first round of surveys took place within 3-6 months of the windstorm event and yearly re-surveys were conducted until 2015. Specific leaf area, leaf dry matter content, leaf thickness, woody density, maximum plant height, and seed dry mass were measured or derived from various sources. Results:There was a pulse of soil nutrient availability in both affected and unaffected areas 1 year after the wind event. Canopy cover and basal area in the affected areas recovered to similar levels as unaffected areas by the second year, and coarse woody debris by the fourth year. In affected plots, taxonomic and functional diversities increased and overshot that of-and taxonomic composition diverged from-unaffected plots after the second year. Young and old-growth secondary forest types mainly differed in the taxonomic composition of new recruits. However, there was no evidence of changes in functional composition towards resource-acquisitive strategies such as lower wood density or higher specific leaf area. Conclusions:Abiotic conditions and basal area recovered rapidly within 2-4 years after the windstorm. Taxonomic composition in young and old-growth affected forests both diverged from unaffected forests but also from each other over time. K E Y W O R D Sblowdown, community composition, edaphic conditions, extreme weather, longitudinal study, plant functional traits, regeneration trajectory, tropical forest, wind disturbance, windthrow | 721 N. (2014). Seven-year responses of trees to experimental hurricane effects in a tropical rainforest, Puerto Rico. Forest Ecology and Management, 332,[64][65][66][67][68][69][70][71][72][73][74]. https ://doi.

Questions: What are the relative influences of soil and hydrology on tree community structure, seedling survival and seedling growth? Do soil and hydrology moderate seedling responses to competition?Location: Nee Soon catchment, Singapore. Methods:We measured and identified trees ≥5 cm diameter in 40 plots measuring 20 m × 20 m each, set up in the wet and dry areas of the catchment, and collected topsoil for analysis of soil texture, pH, and nutrients. We also conducted randomised experiments on seedlings of two dry specialists, two wet specialists, and two generalists and compared survival and growth traits in different soil and waterlogging treatments. We repeated the experiments with one dry specialist and one wet specialist with additional paired seedling intraspecific and interspecific competition treatments.Results: Tree communities were structured along both soil and hydrological gradients, and a distinct freshwater swamp subcommunity was identified. The six species selected for the experiments had differing survival responses to the different soil and waterlogging treatments: dry specialists survived best in the dry soil type and/or well-drained conditions and wet specialists survived best in the wet soil type or waterlogged conditions, with generalist responses in-between. However, both the dry specialist Aporosa frutescens and the wet specialist Baccaurea bracteata grew slower in waterlogged conditions. These results did not differ when seedlings of the two species were grown together, suggesting that dry-specialist seedlings do not particularly outcompete wet-specialist seedlings in the absence of waterlogging stress.Conclusions: Soil characteristics, hydrological conditions, and tree community structure are all intertwined in the field. Manipulative experiments show that soil type and waterlogging have separate effects on seedling survival of different species that are consistent with performance trade-offs corresponding to their respective specialisations, but waterlogging reduces seedling growth in both wet and dry specialists.