Northeastern California, Deer Assessment Unit 2 (DAU) has been identified by the California Department of Fish and Wildlife (CDFW) as an area of critical concern with regard to drastically declining deer numbers (CDFW Report to the Commission). In recent years, the deer population in DAU 2 has declined more than any other to a current low of less than 20% of 1980-1990 population numbers. Historic highs show numbers in excess of 100,000 deer were a part of this region, with 1992 numbers at 90,000 deer and current populations at fewer than 20-25,000 deer (Longhurst & CDFW). Habitat loss, overuse of critical riparian areas by feral horses, and loss of quality forage components have been noted as contributing factors to these declines. Addressing the four main requirements for deer, antelope, elk, birds, and other wildlife; forage, water, cover, and space is not only necessary to survive but to thrive in this region. This is the primary objective of this proposal. Growing deer numbers through restored nutrition and managing their habitat to maximize their place as the umbrella species/indicator of the condition of habitat in the region.
Riparian areas are the ecologically critical zones around streams, seeps, springs, and surface water. Even though these areas make up less than 2% of the western landscape, they support and promote a diversity of resources and intrinsic values for plant, animal, and wildlife communities (Belskey, Matzke 1999). When these ecosystems function properly they act like a sponge, trapping sediments and slowing runoff, allowing water tables to rise and allow hydrological systems to function properly and aid in water retention during dry periods of the year. Healthy, protected riparian areas create critical transition zones that support many developing terrestrial and aquatic wildlife species. The dependency of wildlife species on these critical systems remains a driving force in this restoration and protection effort and is needed to insure these ecosystems remain/become beneficial for continued wildlife use.
Wildlife species including deer, pronghorn, birds, and other sagebrush dependent species require four things to survive: cover, water, forage, and space. Healthy riparian areas provide three of these four requirements, making these areas highly sought after and a critical part of the survival and proliferation of many wildlife species. This high demand has led to damage to the vegetation communities and stream/seep structures, especially from the overuse of feral horses. Unlike livestock, there is no grazing management for feral horses and their long-term presence as well as high population numbers are the cause of excessive impact on an already depleted riparian resource (Snell/Lyle UCCE 2017). Feral horses consume approximately 63% more forage, consume riparian plant species, and use wetland areas more extensively than even cattle do (Menard, Duncan, Journal of Applied Ecology). Restoring these areas and reestablishing the much-needed nutritional values they provide for wildlife is key to expanding deer populations.
Specific Goals and Objectives
- Restore clean water flow to springs, riparian areas, and water systems from the Priority List of Sites from BLM, NRCS, and other agencies (CDFW).
- Address invasive plant species within restoration areas.
- Restore native plant communities that have been changed or degraded by feral horses (over grazing).
- Restore eroded streambanks/water corridors and native woody plant communities that have been denuded of native vegetation by feral horses.
- Protection of these critical vegetation communities, wildlife forage components, and the clean water/hydrology of these riparian areas from excessive use and over grazing of feral horses.
- Monitoring and data collection of treated areas for pre and post treatment comparisons/usage/forage volumes.
- Restoring clean water flow to springs, riparian areas, and water systems will be achieved by conducting maintenance/repair and/or replacement of the following items including, but not limited to: spring boxes, head boxes, associated piping, floats, wells, troughs/drinkers, wildlife guzzlers, wildlife escape ramps, and exclusions. Additional troughs/drinkers, piping, etc. may be added to select project sites, as necessary/designed, by BLM, NRCS, and permittees to facilitate historic use of these water sources outside the exclusionary fencing. This will lessen pressure on the exclusionary fencing from feral horses and cattle.
- Invasive plant species treatment within restoration areas will include mechanical and non-mechanical methods to control such species as (but not limited to): needlegrass, cheat grass, scotch thistle, Canadian thistle, knapweed, and encroachment of juniper. Specific controls and methods will be identified by BLM, NRCS, California Invasive Plant Council (CalIPC), a licensed agricultural pest control advisor, and/or managing agency (CDFW).
- To restore native plant communities, including shrubs and herbaceous plant communities, seeding and plantings of bitterbrush, perennials, and bunch grasses along riparian corridors from locally gathered seed, per BLM, NRCS, and agency (CDFW) guidelines.
- To restore eroded streambanks or water corridors that have been denuded of native vegetation, exclusionary fencing will be utilized to limit/eliminate the impact from feral horses and cattle and promote the natural attenuation of the native plant communities within these areas. Where applicable, seeding and plantings will be utilized to stabilize soil conditions, per BLM, NRCS, and agency (CDFW) guidelines.
- Protection of these critical vegetation communities, wildlife forage components, and riparian areas from excessive use and/or over grazing will be vital to the success of this project. To achieve this, various types of wildlife friendly exclusionary fencing will be utilized along riparian corridors, as well as surrounding head boxes, seeps, and springs. Types of exclusionary fencing includes, but is not limited to: wire, pipe, liberty pipe, and bison fencing per BLM, NRCS, and agency (CDFW) guidelines.
- Monitoring and data collection of treated areas for pre and post treatment comparisons/usage/forage volumes, following research guidelines established by UC Davis UCCE (Snell, Lyle) & BLM and in cooperation with CDFW.
CDFW Selected Priorities
- Invasive Plant Removal/Treatment: In partnership with BLM, NRCS, CDFW, NDOW, and permittees/land owners, this project directly involves removal of the invasive species from project areas. Actions include removal of needlegrass, cheat grass, scotch thistle, Canadian thistle, knapweed, and the encroachment of juniper. Once addressed, establishment of the native plant communities is critical to reducing the encroachment of invasive species. In addition, exclusionary fencing will limit the negative impact from feral horses and grazing on these critical areas, allowing them to re-establish themselves in their natural state.
- Migration Corridor Barriers: In partnership with BLM, NRCS, CDFW, NDOW, and permittees/land owners this project improves the connectivity of the migration corridors of mule deer and antelope in the Northeastern portion of Lassen County. These corridors are currently impeded from the impact of the feral horses in the area. By re-establishing native plant communities and making watering sources available for wildlife along the mule deer and antelope migratory corridors, we open up historic migratory routes and reduce the barriers between winter, summer, and fawning areas.
- Surface Water Management: By restoring springs and clean water flow, surface water will be restored to historical usage and accessible to wildlife through wildlife friendly exclusionary fencing, thus restricting the adverse impact and impediment of feral horses. This provides natural movement of mule deer, antelope, and other species through connectivity of watering sources throughout the landscape.
This project is Phase 1 of a multiyear project/partnership that will restore springs, seeps, and riparian areas across approximately 400,000+ acres. This planned project is a cooperative venture between CDA, BLM, CDFW, NDOW, NRCS, private land owners, local working groups such as Buffalo-Skedaddle Working Group and other NGOs. The expectation is to restore critical forage, water, bedding, and critical space to wildlife in the region. The restoration areas have been prioritized based upon their diversity, key locations, and ability to rebound quickly to reestablish the nutritional benefits as well as other desired components within those corridors. The completion of this project will begin the process of reestablishing connectivity throughout the summer and winter movement areas of deer and antelope herds. Diversion from these areas has led deer and antelope away from critical components due to takeover by expanding feral horse populations. Increased forage, easier access to clean water, cooler bedding and nesting areas due to higher vegetation growth, are all key components to promoting fawn recruitment and retention (Pojar, Bowden, Neonatal mule deer fawn survival and nutrition, Journal of Wildlife Management 2010).
In Southern California, many of the riparian corridors, meadows, and ponds have been overrun by Tamarisk (Tamarix). Not only does this affect the hydrology in these areas, but it out competes native vegetation causing a thick, almost impenetrable barrier that impedes wildlife movement. This issue has been a major focal point of many state and federal agencies in the Southwest Desert Region of the United States.
In 2017, CDA partnered with the Wildlife Conservation Board (WCB) and the California Department of Fish and Wildlife (CDFW) to combat invasive species Tamarisk on the San Felipe Valley Wildlife Area (SFVWA). This is a state-owned property located in eastern San Diego County with the primary focus of deer and deer habitat. SFVWA consists of approximately 17,800 acres acquired and managed by CDFW for the protection and enhancement of mule deer and desert riparian habitat. This property was purchased with the intent of linking them with adjacent Bureau of Land Management (BLM) and California State Park lands.
There have been two previous Tamarisk removal projects on the SFVWA dating back to 2006. Both of these projects have been 100% successful in the removal of the invasive species. This current effort is aimed at completely eradicating the invasive species throughout the remainder of the property.
Many riparian systems within the western Colorado Desert are infested with invasive and non-native plant species such as salt cedar, which can pose a major threat to these sensitive desert habitats. Since salt cedar has the potential to be so damaging to riparian and marsh habitats, it is therefore a species of particular concern for property owners and land managers in this region. Like many invasive species, salt cedar has no natural limiting factors outside its native range. Once established, it can outcompete native plant species and form dense, monotypic stands. Wildlife habitat quality is significantly degraded by these changes in vegetation structure and, in some cases, by the creation of physical barriers that can prevent wildlife access to water sources. Additionally, salt cedar is a prodigious water user that can further reduce water availability for native plant and animal species.
Additional concerns about salt cedar are related to changes in natural water flow patterns and soil chemistry. Dense stands create large amounts of excess biomass that can potentially impede water levels and heighten flood risk during periods of high-water flow. Increased erosion, streambank scouring and altered hydrology are frequently the result of dense infestations. Salt cedar is reported to accumulate high salt concentrations in its foliage. Subsequent leaf drop of these high salt content leaves may increase soil salinity and discourage the growth of other, more desirable plant species at infested sites.
Salt cedar removal enhances and protects biodiversity, watershed health and special status species and also reducing the risk of wildfire to the nearby communities of Julian and Shelter Valley. San Felipe Creek has long served as a primary stopover for migrating birds in the arid Colorado Desert and is an important resource for state and federally-listed species such as peninsular bighorn sheep, least Bell’s vireo, southwestern willow flycatcher, and yellow-billed cuckoo.
Successful completion of this project on the SFVWA and in the San Felipe Creek watershed would fulfill objectives of the multi-agency MOU regarding conservation and management of desert watersheds in San Diego and Imperial Counties. Restoration of natural conditions along this valuable riparian system, as well as the protection of rare, threatened, endangered, and special status species, are prime concerns of the state and federal land management agencies managing lands in the region.
Initial treatment of the 418 acres of Tamarisk in the SFVWA began during the fall of 2018 and was completed in February of 2019. The removal consisted of hand cutting and chipping all tamarisk and following up with an herbicide on the stumps to prevent new growth. Overall, the project has been 100% successful and has already made an immediate impact to the San Felipe Creek during the rainy season this past winter.
Over the next three years, CDA and CDFW will be monitoring and treating the 418 acres where the Tamarisk removal took place to ensure the success of the project. In the meantime, several water projects both on the SFVWA and in the Colorado Desert have been identified and have secured funding to implement during 2019 and in the spring of 2020.