This tutorial provides heightmaps, links to them, and talks about what to look for. It is written from the point of view of someone wanting to use them for modelling terrain in Blender, but it is relevant to modelling with other 3d packages
A small garden can have a big impact on our native animals. The value is not in attracting animals but through beauty inspiring the visitor to value the life around them. This article covers the design and planting of this garden.