Effect of time and diet change on the bacterial community structure throughout the gastrointestinal tract and in faeces of the northern brown bandicoot, Isoodon macrourus

A significant gap, in not only peramelid nutritional physiology but marsupial nutrition as a whole, is the lack of information relating to microorganisms of the gastrointestinal tract. This research is a preliminary investigation that will provide a baseline for comparisons among peramelids. The high degree of 16S rRNA gene clones identified in this research that are closely related to culturable bacteria suggests that additional research will enable a more complete description of the gastrointestinal bacteria of I. macrourus. Most identifiable clones belonged to Clostridium and Ruminococcus. This research has confirmed that the hindgut of I. macrourus, the caecum, proximal colon and distal colon, are the main sites for microbial activity.

Long term repeated fire disturbance alters soil bacterial diversity but not the abundance in an Australian wet sclerophyll forest

Effects of fire on biogeochemical cycling in terrestrial ecosystem are widely acknowledged, while few studies have focused on the bacterial community under the disturbance of long-term frequent prescribed fire. In this study, three treatments (burning every two years (B2), burning every four years (B4) and no burning (B0)) were applied for 38 years in an Australian wet sclerophyll forest. Results showed that bacterial alpha diversity (i.e. bacterial OTU) in the top soil (0-10 cm) was significantly higher in the B2 treatment compared with the B0 and B4 treatments. Non-metric multidimensional analysis (NMDS) of bacterial community showed clear separation of the soil bacterial community structure among different fire frequency regimes and between the depths. Different frequency fire did not have a substantial effect on bacterial composition at phylum level or bacterial 16S rRNA gene abundance. Soil pH and C:N ratio were the major drivers for bacterial community structure in the most frequent fire treatment (B2), while other factors (EC, DOC, DON, MBC, NH 4 +, TC and TN) were significant in the less frequent burning and no burning treatments (B4 and B0). This study suggested that burning had a dramatic impact on bacterial diversity but not abundance with more frequent fire.