Does invasion by Pteridium aquilinum (Dennstaedtiaceae) affect the ecological succession in Atlantic Forest areas after a fire?

Pteridium aquilinum (Dennstaedtiaceae) colonization affects ecological and restoration processes. The knowledge of the impacts on the ecological succession by this species allows the use of restoration strategies in invaded environments. This work aimed to evaluate the floristic composition, diversity, structure, density, basal area, height, and diameter of natural regeneration in three areas of the Atlantic Forest in the Serra do Espinhaço Biosphere Reserve in an area invaded by P. aquilinum after a fire. Three environments with different coverage intensities by P. aquilinum were studied, and the plants over 10 cm in height or 5 cm in canopy diameter were measured. The floristic composition and diversity were analyzed using indices presented by Chao, Fisher, Margalef, Pielou, Shannon-Weaver, and Simpson, and similarity was evaluated by the Jaccard index. Species density, basal area, height, and canopy diameter classes were also evaluated. The floristic composition, diversity, structure of natural regeneration, density, and basal area were higher in post-fire areas with a lower coverage by P. aquilinum. The topsoil coverage with plant litter and the possible effect of P. aquilinum allelopathy probably reduced the species richness and diversity. The proportion of plants from the lowest height and canopy diameter classes was higher under moderate coverage by P. aquilinum. The reduction in the floristic composition, diversity, number of species, and basal area in post-fire areas colonized by P. aquilinum is probably due to this species aggressiveness. The population of this plant is high, accumulating large quantities of plant litter as a physical barrier preventing light and propagules from reaching the soil, reducing the germination of the seed bank and, consequently, the natural regeneration. The floristic composition, diversity, structure of natural regeneration, density, and basal area were lower in areas with higher coverage by P. aquilinum. The proportion of plants in the most significant height and canopy diameter classes was higher with reduced coverage by P. aquilinum. The P. aquilinum reduced forest succession in areas after a fire.

Energy reserves of Artibeus lituratus (Chiroptera: Phyllostomidae) in two areas with different degrees of conservation in Minas Gerais, Brazil

Forest fragmentation associated with the expansion of human development is a phenomenon that occurs worldwide. Studies reveal that there have been both a decline in species diversity and a decrease in Neotropical bat population size because of habitat loss. The aim of this study was to investigate whether human action has been affecting the food availability to wildlife species, which could impact the storage of body energy reserves. For this purpose, fruit-eating bats (Artibeus lituratus) were collected in two areas in Minas Gerais state, Brazil. The concentrations of plasma glucose, as well as glycogen, lipids and protein in liver in muscles were performed, in addition to adipose tissue weight and carcass fatty acids. Our results indicate that fat reserves were significantly lower in most tested tissues (muscle of the hindlimbs, breast muscles, adipose tissue and carcass) in animals collected in the region with a higher degree of human disturbance. The other parameters showed no significant differences in the groups collected at different locations. In conclusion, we suggest that human action on the environment may be affecting the storage of body fat energy reserves of this species during the autumn, particularly in metropolitan region areas of Belo Horizonte, MG - Brazil, requiring special attention to the species conservation.

Short-term effects of a spinosyn's family insecticide on energy metabolism and liver morphology in frugivorous bats Artibeus lituratus (Olfers, 1818)

A new class of insecticide derived from fermentation of Sacharopolyspora spinosa - spinosad, has been indicated as being of low toxicity and a natural alternative to classical pesticides. In order to elucidate several aspects related to the morphophysiological changes induced by spinosad in Artibeus lituratus, the effects of a seven-day administration on plasma glucose, glycogen, protein and lipid concentrations were evaluated, and possible changes in liver cells were examined by histological analysis. Animals were fed with spinosyn-contaminated fruit through immersion in a solution. Data reporting on metabolism revealed a decrease in hind limb muscle lipid concentration in the treated group. Morphological analysis indicated a significant increase in liver cell diameter in treated animals compared to the control group. This study indicates that spinosyn, used at its recommended dose, does not affect general energy metabolism in A. lituratus but may affect some ultrastructural characteristics of liver cells.