The main factor responsible for species decline and extinction today is HABITAT LOSS.
I would like to address what habitat loss is, what it means, and why it is a big deal in conservation. Where a species lives, finds food, socializes, mates, and reproduces is its habitat. Habitat is varied and depends on which species you are talking about. If a species loses habitat, there is less area in which to live, find food, socialize, mate, and reproduce. As habitat loss increases individuals are forced into smaller areas, often leading to situations where the remaining habitat cannot sustain the former population, resulting in die-offs.
Habitat loss is the biggest factor in species extinction (Fahrig 1997, Groom et al. 2006, Groombridge 1992, Tilman et al. 1994). Let me rephrase that, habitat loss is the largest single cause of species extinction. This is not to say that species do not face extinction for other reasons; they do. Nor is it to say that there are not compounding effects between two or more factors that result in species decline, for example, habitat loss may lead to fragmentation of the landscape, increasing disease transmission in stressed populations.
The placement of utility-scale solar facilities in the Mojave Desert results in permanent habitat loss because of the extensive habitat modification required to build these facilities in wildlands (Abella 2010, Lovich & Bainbridge 1999). Habitat loss is further exacerbated by peripheral impacts that support these facilities (roads, transmission lines). To get an idea of the scale of habitat loss in the Ivanpah Valley (along the California/Nevada border), look at the maps of the same area before (Figure 1) and after development (Figure 2). Note that Figure 2 does not include many of the roads in the Valley, or the smaller developments in the area such as mines and quarries; therefore the scale of habitat loss is actually greater than depicted.
Figure 1. Map of the Ivanpah Valley prior to developments. Figure 2. Map of the Ivanpah Valley after developments.
The utility-scale solar developments could have been placed closer to the southern California and Nevada cities for which they provide electricity, or better yet, within the cities themselves on rooftops, parking structures, roadways, and vacant lots. Sadly, this level of habitat loss was preventable. If this pattern continues to be repeated much of our desert public lands will be lost not only for native species, but also for our recreation. However, there are smarter, more efficient (less energy is lost in transmission when solar is close to cities), and less destructive places for solar energy that we could have used and will hopefully use in the very near future.