RESUMEN
Secondary forests represent a significant proportion of global forest cover, with over 70% of forests in East Asia classified as regenerating. While succession has been studied extensively in temperate systems, trajectories of subtropical succession remain poorly characterized in highly disturbed, urban-adjacent forests. Investigating the additive beta diversity components of turnover and nestedness may reveal community assembly mechanisms driving secondary succession. The present study investigates plant community assembly along a successional gradient from 7 to 70 years following the onset of succession in secondary subtropical forests in Hong Kong, China. Plant survey data for 28 plots were analysed, generating additive Simpsons turnover and nestedness beta diversity metrics. Dissimilarity matrices were generated and modelled as a function of environmental matrices including forest plant community age (years following onset of secondary succession), inter-community distance (metres), and soil moisture saturation (%) across three elevational bands using generalized dissimilarity models. Nonmetric multidimensional scaling of plant communities was conducted with Bray-Curtis dissimilarity matrices. Inter-community distance and successional age differentially influenced plant species turnover between lowland and Montane forest types. Models of nestedness found that plot age and soil moisture saturation were significant drivers of nestedness patterns in plant communities across elevational classes. Turnover represented a higher proportion of Sorensen beta diversity than nestedness, while ANOSIM found significant differentiation between plant communities at different successional stages. Turnover patterns suggest a deterministic model of community assembly, with strong patterns of species replacement between communities at fine spatial scales and successional stages, as well as clear compositional shifts between lowland and montane forest types. NMDS analysis and functional compositional assessments suggested a transition from early successional communities with a high proportion of shrub species, to later successional communities with a higher proportion of tree species, with an increase in species turnover with greater age dissimilarity.
RESUMEN
A series of sulfenimide derivatives (1a-i) were investigated as inhibitors of human (hCA-I, hCA-II) and bovine (bCA) carbonic anhydrase enzymes. The compounds were synthesised by the reaction of substituted thiophenols with phthalimide by means of an effective, simple and eco-friendly method and the structures were confirmed by IR, 1H NMR, 13C NMR, MS and elemental analysis. All derivatives except for the methyl derivative (1b) exhibited effective inhibitory action at low micromolar concentrations on human isoforms, but only four derivatives (1e, 1f, 1h, 1i) inhibited the bovine enzyme. The bromo derivative (1f) was found to be strongest inhibitor of all three enzymes with KI values of 0.023, 0.044 and 20.57 µM for hCA-I, hCA-II and bCA, respectively. Results of our study will make valuable contributions to carbonic anhydrase inhibition studies for further investigations since inhibitors of this enzyme are important molecules for medicinal chemistry.