Here’s the good news. We have species to protect. The Morongo Basin and surrounding mountains have open spaces that can dependably provide desert tortoise with broad fields of spring dandelions, bobcats with sunny rock outcrops, bighorn sheep with secluded lambing areas, and badgers with extensive open grounds that support abundant burrowing rodents.
Each of these four species is an area-dependent animal, meaning that their populations thrive only when their specialized habitat requirements are available. Their habitats must be on a large enough scale, be relatively unfragmented by paved roads and housing developments, and be available year around and into the future. If the needs of these animals are met, we are told, then a suite of other species, including plants, invertebrates, reptiles, birds and mammals, will also have their diverse ecological requirements met.
This good news comes with a road map for maintenance: A Linkage Design for the Joshua Tree - Twentynine Palms Connection, released in December 2008 by South Coast Wildlands. South Coast Wildlands is a collaborative network of agencies and organizations working to identify the highest priority linkages connecting the wildlands of California-Northern Baja California. This project was kicked off in 2000 at a statewide workshop at the San Diego Zoo. Of the 232 linkages identified as important to conserve, the Joshua Tree -Twentynine Palms desert connection was identified as one of the 46 linkages that must be maintained if California’s unique biodiversity is to persist.
What makes us so special? We have the species and we have the habitats that can be linked. If we pay close attention to the requirements of the four chosen focal species: bighorn sheep, badger, desert tortoise, and bobcat, then the needs of 21 other species representative of plants, invertebrates, reptiles, birds, and mammals, can be met.
The needs include everything from the specialized pollinating insects for particular plants, to sandy soils needed for burrowing, to the cover that protects prey from predator, as well as the prey needs of the predator. A bighorn sheep could cross a linkage several times a year looking for browse, water, or a ready mate. A tortoise might take a couple of generations to cross; Mirriam’s kangaroo rat much longer. But without the ability to cross, to be part of the suite of species immigrating and emigrating across the basin over time, the mountainous areas – the Little San Bernardino Mountains (Joshua Tree National Park) and the Bullion Mountains (29 Palms Marine Base) will become islands of habitat with steadily diminishing numbers of individuals and species.
Linkages are described as permeable or open to movement based on how difficult it is for each species to cross. Four landscape characteristics are considered: elevation, vegetation, topography, and road density, and ranked from 1 (preferred) to 10 (avoided) for each species. This information is fed into a Geographic Information System (GIS)-based technique that models the relative cost for a species to move between core living areas within the linkage. The map accompanying this article shows the final linkage design.
The connections are not pristine, many of us live in them, and more will yet. Conservation purchases and easements and local government land use policies will be necessary to conserve the linkages. We also have choices to make that will benefit our wildlife neighbors. For instance, lighting should be shielded and focused away from the linkage and toward the house, pets should not run wild, wild animals should not be fed. The good news remains: we have wildlife and only we can protect it.
You can learn more about The South Coast Missing Linkage Project and read the reports on www.scwildlands.org.
This article,”Linkages Found” by Pat Flanagan, appeared in the April/May 2009 issue of SunRunner Magazine.
Painting © Diane Best