Preserving biodiversity is difficult for many reasons. Biodiversity is complex and changing, and also includes all hierarchical levels ranging from genes to ecosystems. Furthermore, it is complicated to include all the ecological and evolutionary processes in which biodiversity participates, making it unmanageable to conserve it all. However, we need to know the basic aspects of biodiversity such as: where it is, and what it is doing in those spaces. Simultaneously, the work of conservation biologists is to identify which of the "apocalypse riders", or man-made factors, are affecting biodiversity at different points in time and space, and suggest actions to counteract or diminish their effects. The riders of the apocalypse are the loss of habitats, fragmentation, illegal hunting/trafficking, pollution, climate change, and dispersion of alien invasive species.
