Hodges Reservoir-Bernardo Bay Cactus Wren Habitat Restoration Grant Project

Project Focus

Target species: Cactus Wren, Coastal cactus wren

Main implementing entity: City of San Diego, Public Utilities Department Watershed and Resource Protection Team

Partner: San Diego Association of Governments; San Diego Zoo Institute for Conservation Research; San Dieguito River Park; San Dieguito River Valley Conservancy

Point of contact: John Barone

Project Page manager: Sarah McCutcheon

SDMMP lead: Sarah McCutcheon

Study lead: John Barone

Coastal cactus wren Campylorhynchus brunneicapillus sandiegensis

Goal: Protect, enhance, and restore suitable cactus scrub habitat for coastal cactus wrens to increase effective population size in each genetic cluster at a short term sustainable level (e.g. 50-100 wrens), rehabilitate habitat destroyed by wildfire, improve habitat quality to maintain populations during drought, enhance connectivity within and between genetic clusters to increase genetic diversity and rescue small populations, and manage anthropogenic predation risk to ensure the long term persistence (>100 years) of cactus wrens on Conserved Lands in the MSPA.

regional and/or local NFO 2017, 2018, 2019, 2020, 2021 SO

MGT-IMP-IEX CAMBRU-7

Management units: 5, 6

In 2017-2021, continue supporting restoration of cactus scrub based upon ICR's Restoration Analyses for the San Pasqual Valley/Lake Hodges coastal cactus wren genetic cluster (see occurrence table) to: rehabilitate cactus scrub destroyed or degraded by the 2007 Witch Fire; to expand occurrences, particularly adjacent to Lake Hodges; to improve connectivity within the genetic cluster; and as needed, to manage high risk of anthropogenic predation of adults and nestlings.

Action	Statement	Action status	Projects
IMP-1	Following best practices, design cactus scrub enhancement and restoration projects to provide high quality nesting and foraging habitat with large patches of cacti >1 m tall in a mosaic of open scrub that provides sufficient food resources for reproduction and survival, especially during drought years when arthropod food resources are limiting. As they become available, incoporate the results from the Cactus Wren Demography, Foraging and Arthropod Study to create restoration palettes that favor plant species associated wtih important wren food resources. Design planting layouts to maximize water availability by allocating a portion of the plantings to more mesic sites, such as ravines, at the bottom of slopes, and on northerly and easterly aspects. Control invasive nonnative plants to =20% absolute cover to reduce competition with native plants for water and light.	in progress	Hodges Reservoir-Bernardo Bay Cactus Wren Habitat Restoration Grant Project
IMP-2	Implement management actions, as needed, to reduce anthropogenic predation on wrens and their nests in fragmented habitats bordered by development where wrens are vulnerable to predation by cats, Cooper's hawks, corvids and other human-subsidized predators. Actions could include removing selected trees within or bordering cactus scrub that provide hunting, roosting, and nesting perches for hawks and corvids and avoiding cactus scrub restoration in areas where the terrain and location make wrens especially vulnerable to predation. Other measures could involve humanely removing feral cats from Conserved Lands and providing educational material and signage encouraging neighboring homeowners to keep their cats indoors so that wrens are protected and cats are safe from predation by wild animals, such as coyotes.	in progress	Hodges Reservoir-Bernardo Bay Cactus Wren Habitat Restoration Grant Project

Criteria	Deadline year
By 2021, =2 High Priority Management Actions Implemented from ICR's Restoration Analyses for the San Pasqual Valley and Lake Hodges	2021

Threat Name	Threat Code
Altered fire regime	ALTFIR
Climate change	CLICHN
Invasive plants	INVPLA
Loss of connectivity	LOSCON
Urban development	URBDEV

Code	Obj. code	Statement
CAMBRU-3	MON-SURV-SPEC	From 2017 to 2021, use a standardized protocol to survey for cactus wrens to determine territory, pairing and banding status and collect habitat covariate data in cactus scrub habitats on Conserved Lands in the Otay and San Diego/El Cajon genetic clusters (see occurrence table). In 2018 and 2021, expand surveys to include the San Pasqual Valley/Lake Hodges genetic cluster.
CAMBRU-4	MON-RES-SPEC	From 2017 to 2019, continue the Coastal Cactus Wren Demography, Vegetation and Arthropod Study begun in 2015 to investigate relationships between habitat quality and wren reproduction, dispersal and survival in the Otay and San Diego/El Cajon genetic clusters (see occurrence table). Habitat quality is measured at the territory scale and characterized by vegetation attributes, arthropod community composition, nestling diet, and potential availability of arthropod prey based on plant associations. Use the results to develop specific restoration recommendations to enhance habitat suitability and food resources important to cactus wren reproduction and survival.
CAMBRU-5	MON-RES-GEN	From 2017-2019, in conjunction with standardized surveys and with banding activities for the Coastal Cactus Wren Demography, Vegetation and Arthropod Study, collect feather or blood samples from nestling and adult cactus wren at sites where wrens were sampled in 2011-2012 for the Southern California Cactus Wren Genetics Study (Barr et al. 2013, 2015). Determine if genetic diversity and effective population size have changed in the Otay, San Diego/El Cajon, and San Pasqual genetic clusters (see occurrence table) and evaluate whether there are potential threats to long-term population sustainability from inbreeding. Based on these results, prepare specific recommendations for managing gene flow and/or population expansion to enhance genetic diversity and effective population size.
CAMBRU-6	MGT-IMP-NUR	From 2017-2021, continue operation of the North San Diego County Cactus Nursery and support a South San Diego County Cactus Nursery to supply cactus to land managers to enhance, restore and create coastal cactus wren habitat. Grow cactus pads, segments and entire plants sufficient for restoration projects to expand and enhance cactus scrub habitat and as a source of plants for immediate habitat rehabilitation following severe wildfire.
CAMBRU-8	MON-IMP-MGTPL	From 2017-2021, collect data on the effectiveness of implementing high priority management actions to restore cactus scrub to expand coastal cactus wren populations and enhance connectivity within the San Pasqual Valley/Lake Hodges genetic cluster (see occurrence table). In 2021, compile data from all restoration projects and determine the effectiveness of cumulative management actions for north San Diego County. Use these results to develop a management strategy that will provide the basis for preparing a North County Coastal Cactus Wren Habitat Conservation and Management Plan in 2022.
CAMBRU-9	MGT-IMP-FMGT	Implement prefire management to reduce potential severity and impacts from future fire at prioritized cactus wren occurrences and habitats most at risk from wildfire.