Invasions can be close to home

At the southern end of Santa Clara valley we are getting nitrogen deposition because of the automobile combustion and some agriculture. Thus, more nitrogen is being added to natural systems. We're now producing artificially more nitrogen than is being fixed biologically. There's an enormous amount of nitrogen being added to the terrestrial landscape. These additions of nitrogen are favoring invasive species in the Santa Clara Valley as shown by the work of Stuart Weiss at Stanford.

So, not only are we going to have more invasives, but their impact is going to be considerable and they will cause feedbacks to how the biosphere operates and how evolution operates. For example, Erika Zavaleta at Stanford just did a calculation of how much water we're losing in terms of dollars from the invasion of tamarisk into the Colorado River Basin. We're talking substantial amounts of money, as well as changes in geomorphology and nutrient cycling. So we're going to get feedback from these invasives that will alter many ecosystem features.

Narrative Index

Table of Contents

BioForum Index

AE Partners Collection Index

Activities Exchange Index