Characterization of phytoplankton assemblages in a tropical coastal environment using Kohonen self‐organizing map

This study was aimed at understanding the main abiotic environmental factors controlling the distribution patterns of abundance and composition of phytoplankton (size less than 10 μm) assemblages in the coastal waters of south‐eastern Côte d'Ivoire. Data were collected during two cruises, in January (low‐water period) and October (high‐water period) of 2014. A total of 67 species were identified and assigned to Bacillariophyceae (49%), Cyanophyceae (21%), Chlorophyceae (13%), Euglenophyceae (10%), Dinophyceae (4%) and Chrysophyceae (3%). Three biotic zones (I, IIA and IIB) were distinguishable on a Kohonen self‐organizing map after an unsupervised learning process. The diatom genera Eunotia sp., Navicula sp. and Actinoptychus senarius are significantly associated with I, IIA and IIB biotic zones, respectively. A clear seasonal cum salinity trend was apparent in phytoplankton distribution patterns. Turbidity and nitrate levels were the main abiotic factors controlling phytoplankton distribution in I, the upland tidal regions of the lagoon. In regions along the lagoon–sea continuum, phosphate and turbidity exert the most control during the low‐water season (IIA), while total dissolved solids control phytoplankton distribution during the high‐water season (IIB). These are climate‐sensitive parameters whose concentrations depend on prevailing hydroclimatic processes. Therefore, seasonality can have important consequences on phytoplankton community and inadvertently the productivity of these systems.     

Diversity and abundance of macrofungi in rubber agroforests in southwestern Nigeria

The mushroom diversity was studied for 14 months in Edo State, southwestern Nigeria. A total of 76 macrofungi tantamount to 333 fruit bodies were encountered, 74% of which were identified and named. The basidiomycetes and members of the family Tricholomataceae were the best represented taxa while species on wood‐based substrates made up 66% of the total mushroom taxa. The monthly mushroom abundance profile, diversity and species richness for each sampled plot correlated with local meteorological factors, age of the sampled sites and distribution of wood‐based substrates. Jaccard, Sorensen and Bray–Curtis similarity index values showed that plots A and D, representing young actively managed and old abandoned rubber tree plantations, respectively, were the most dissimilar in mushroom composition. The hypersensitive response of macrofungal fruit bodies to climate variables qualify mushrooms as veritable biomonitors or bioindicators of climate change. This study supported earlier reports that rubber agroforests are a depauperate pool of utilitarian mushrooms.