The response of an arboreal mammal to livestock grazing is habitat dependant

Abstract Inappropriate livestock grazing is implicated in the decline of vertebrate fauna species globally. Faunal responses to grazing can interact with the vegetation community in which they occur. We measured the response of an arboreal marsupial, the common brushtail possum (Trichosurus vulpecula vulpecula) to different cattle grazing strategies and vegetation types, and examined whether micro-habitat selection is driving this response. We hypothesised that where arboreal habitat is intact, brushtail possums would be resistant to the impacts of heavy grazing. We conducted a mark-recapture survey among four grazing treatments and in two vegetation types (Box and Ironbark), at a 20-year grazing trial in northern Australia. We found that brushtail possums were resistant to the impact of heavy grazing in both vegetation types, but preferred the heavy grazing treatment in the Box vegetation type. Complex arboreal habitat and low ground cover was preferred, and high grass cover and low tree species richness avoided. Most individuals exclusively used one vegetation type, with few using both, suggesting a ‘matrix’ vegetation between the Box and Ironbark may be creating a movement barrier. Vegetation type should provide a context for determining the benefits to arboreal wildlife of adopting a particular grazing management strategy

Mouse Models of Liver Fibrosis Mimic Human Liver Fibrosis of Different Etiologies

The liver has the amazing capacity to repair itself after injury; however, the same processes that are involved in liver regeneration after acute injury can cause serious consequences during chronic liver injury. In an effort to repair damage, activated hepatic stellate cells trigger a cascade of events that lead to deposition and accumulation of extracellular matrix components causing the progressive replacement of the liver parenchyma by scar tissue, thus resulting in fibrosis. Although fibrosis occurs as a result of many chronic liver diseases, the molecular mechanisms involved depend on the underlying etiology. Since studying liver fibrosis in human subjects is complicated by many factors, mouse models of liver fibrosis that mimic the human conditions fill this void. This review summarizes the general mouse models of liver fibrosis and mouse models that mimic specific human disease conditions that result in liver fibrosis. Additionally, recent progress that has been made in understanding the molecular mechanisms involved in the fibrogenic processes of each of the human disease conditions is highlighted