Maintenance of ecological functions and disturbance regimes within ecosystems is as important as preserving species populations or their genetic structure, biotic communities, and landscapes. There is considerable dispute as to how species diversity influences productivity and stability of various ecosystem structural and dynamic attributes. Some view each and every species as making an incremental  contribution  to these features. Others assume that some redundancy exists. Addition or loss  of species can be anecdotally shown to influence ecosystems in proportion to the role such organisms have in altering microclimate, capturing energy, cycling nutrients, and serving as food and habitat for other organisms. Subtle but essential  interactions are easy to overlook, however. We should try to keep all the parts until  more definitive research  is available  on  this topic. Sustainable development will require balancing resource use with maintenance of our natural legacies. Ecosystem perspectives  must contribute  to decisions  on where the balance exists.