Planning Phase Of Salt Creek RestorationKyle Mulroe, TLD Conservation Biologist January 24, 2021
There are very few places left around the Salton Sea where the desert pupfish can be found in the wild. Drying of natural aquifers, increasing salinity of the Salton Sea, competition from invasive species such as sailfin mollies, crayfish, golden apple snails and tamarisk – each of these changes and threats has taken a drastic toll on our one native desert fish species. When this project was first proposed to us, these were some of the factors I researched in the literature to see how The Living Desert could be part of a successful restoration of Salt Creek. Ultimately our target is the removal of the water hungry tamarisk from the creek, but we were aware of the many threats to the desert pupfish in and around the Salton Sea.
With the case for removing tamarisk from Salt Creek quite clear (see previous blog article), we looked into how to remove this notoriously aggressive species. There are papers for and against controlled burns, specific herbicides, heavy machinery versus hand tools, specific months and seasons for removal – decades of work trying to control or remove this invader of the American southwest. We decided to use hand-tool control methods: chainsaws and loppers coupled with well tested herbicides to prevent future growth. And even with a successful removal, we need to restore native plant species in its place to prevent future germination of tamarisk.
We set out to survey and identify the plant species found in the Salt Creek watershed, both in the riparian zone and further upland. Deciding which species to plant in tamarisk’s place is like a many-circled Venn diagram: which species we can successfully propagate on our zoo grounds, the time it takes for a plant to mature enough to be out planted, the salt tolerance of the species given the high salinity of the soil, the amount of cover a plant will provide to block growth of tamarisk – and on and on. Luckily Natalie Gonzalez, our Assistant Conservation Scientist has taken up the challenge, leading the way with seed collection and propagation up at our greenhouses with the assistance of our extremely knowledgeable Garden Department.
Site access was another challenge with this project, as our selected area for restoration is quite remote. We tested four routes into the site, with drive times ranging from 35 minutes to an hour and ten minutes off of the nearest paved road - each with their own pros and cons depending on the season and weather. This is four-wheel-drive territory, bring a shovel to dig your wheels out territory, let someone know where you are going and when you’ll be back territory. Dr. James Danoff-Burg, Director of Conservation found us the fastest route on a trip in which he rode his mountain bike to our site, pioneering a route we were told was inaccessible to vehicles.
With our removal and planting strategy ready to be tested, site routes and maps in place, we broke ground (and tamarisk root) in the Salt Creek restoration.
We thank Coachella Valley Mountain Conservancy for the funding of this project, and thank the Bureau of Land Management and the California Department of Fish and Wildlife for their generous collaboration.