Spatio-temporal variability of benthic macrofauna in a coastal lagoon assessed by ecological interaction networks

An ecological survey of the benthic communities was carried out, at both spatial and temporal scales, in Papapouli Lagoon, the first ecotouristic park in Greece by applying for the first time, ecological network analysis. The application of ecological network analysis provided novel information on the quality of interactions among species, undetected by the most frequently used methods. The sorting of substrate samples enabled the identification and density determination of 40,036 individuals belonging to 31 different taxa, although, strong dominance of only a few species was observed. “Deposit feeders” were the dominant trophic group in all sampling sites and seasons while “suspension feeders” exhibited relatively the lowest abundance. The periodic opening of the sea inlet seems to be of crucial importance. In coastal lagoons, where there is constant communication with the sea, benthic fauna patterns seem to change according to the sea-land gradient. However, in intermittently closed lagoons, such as Papapouli Lagoon, a more homogenous pattern is evident. The obtained networks showed that when communication with the sea is interrupted all the benthic fauna patterns tend to be destabilized and centralized around one species, which in most cases is a “deposit feeder”. When the inlet opens and communication with the sea is restored, the benthic composition seems to be more cohesive, especially in the most distant regions. Knowledge generated by network analysis should provide a valuable tool in order to assess potential environmental changes and assist management decisions

Soil biochemistry and microbial activity in vineyards under conventional and organic management at Northeast Brazil.

The São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that orgThe São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that organic fertilization can improve soil quality, we compared the effects of conventional and organic soil management on microbial activity and mycorrhization of seedless grape crops. We measured glomerospores number, most probable number (MPN) of propagules, richness of arbuscular mycorrhizal fungi (AMF) species, AMF root colonization, EE-BRSP production, carbon microbial biomass (C-MB), microbial respiration, fluorescein diacetate hydrolytic activity (FDA) and metabolic coefficient (qCO2). The organic management led to an increase in all variables with the exception of EE-BRSP and qCO2. Mycorrhizal colonization increased from 4.7% in conventional crops to 15.9% in organic crops. Spore number ranged from 4.1 to 12.4 per 50 g-1 soil in both management systems. The most probable number of AMF propagules increased from 79 cm-3 soil in the conventional system to 110 cm-3 soil in the organic system. Microbial carbon, CO2 emission, and FDA activity were increased by 100 to 200% in the organic crop. Thirteen species of AMF were identified, the majority in the organic cultivation system. Acaulospora excavata, Entrophospora infrequens, Glomus sp.3 and Scutellospora sp. were found only in the organically managed crop. S. gregaria was found only in the conventional crop. Organically managed vineyards increased mycorrhization and general soil microbial activity