Invasive Species
GR: Human-introduced animals, plants, and disease organisms have destroyed many species and ecosystems. This aspect of the human impact on nature became a global disaster in the 1500’s as we began crossing the oceans. In the lands we reached, we rampaged about with no thought of the seeds stuck to our boots or the diseases carried by our livestock. Then we developed nature. We cut the soil and filled it with pipes and wires and then we entombed its microorganism ecosystem with pavement. We damned streams, dried up springs, cut the forests, stripped the land with cattle and sheep, and we poisoned the water and air. Now comes our grand slam: We’ve added sufficient greenhouse gasses to the atmosphere to give our climate warmer temperatures, droughts, fires, and stronger storms.
How do we react to all that we’ve done? In the current time of competition between oil producers, for example, the temptation to burn more of the cheaper gasoline doesn’t horrify us, no, we call the lower prices a consumer blessing. 
And so, in all that we do, our species appears to be striving for maximum destruction of earth ecosystems. Here are a few essays I wrote about how this works with invasive plants.
The following article is by Ken Cole on the Wildlife News website (February 19, 2016).
Bighorn sheep photo copyright by Ken Cole
“On Sunday and Monday, February 14-15, 2016, USDA Wildlife Services took to the skies and shot the remaining 24 bighorn sheep in the Montana Mountains of northwest Nevada at the request of Nevada Department of Wildlife.
“While the exact source of the disease outbreak is not known, it is not surprising that the bighorn sheep in this area are suffering this fate because there are two domestic sheep grazing allotments – the Bilk Creek allotment and the Wilder-Quinn allotment – in the middle of this area and BLM ignored the disease threat that they pose to bighorn sheep.
“In 2012 the BLM began the permit renewal process for one of the allotments – the Bilk Creek allotment – and Western Watersheds Project submitted comments notifying them of our concern about the risk that domestic sheep posed to bighorn sheep in this area. It is well know that domestic sheep are carriers of pathogens that result in deadly pneumonia to bighorn sheep and that even just one nose-to-nose contact between these related species can result in a disease outbreak that commonly kills up to 90% of a herd and kills the offspring of the remaining animals for up to a decade.
“In 2013 the BLM issued the Final Environmental Assessment that dismissed those concerns . . . . ” Read more at: http://www.thewildlifenews.com/2016/02/19/bighorn-sheep-die-off-in-montana-mountains-nevada-is-it-any-wonder.
GR: The ignorance displayed by this range manager is shocking. It should remind us all that focusing too closely on a single goal can cause us to overlook critical alternatives. This article describes an instance where managing nature to benefit domestic livestock creates a willingness to take chances. Range managers have gambled on new techniques and new species for many years. They ignore negative possibilities and focus on their goal—more food for cows or sheep. They do not consider ecosystem responses to their new techniques. They do not consider the effects on on soil microorganisms, and they do not worry about future invasion potential. The result of similar “range management” has been the loss of more than 100-million acres of productive native grasslands and shrublands in the western U. S. 
GarryRogers Nature Conservation 