Conservation Gap Analysis of Native U.S. Oaks Species profile: Quercus cedrosensis Emily Beckman, Duncan Bell, Cheryl Birker, Abby Meyer, Murphy Westwood SPECIES OF CONSERVATION CONCERN CALIFORNIA SOUTHWESTERN U.S. SOUTHEASTERN U.S. Channel Island endemics: Texas limited-range endemics State endemics: Quercus pacifica, Quercus tomentella Quercus carmenensis, Quercus acerifolia, Quercus boyntonii Quercus graciliformis, Quercus hinckleyi, Southern region: Quercus robusta, Quercus tardifolia Concentrated in Florida: Quercus cedrosensis, Quercus dumosa, Quercus chapmanii, Quercus inopina, Quercus engelmannii Concentrated in Arizona: Quercus pumila Quercus ajoensis, Quercus palmeri, Northern region and / Quercus toumeyi Broad distribution: or broad distribution: Quercus arkansana, Quercus austrina, Quercus lobata, Quercus parvula, Broad distribution: Quercus georgiana, Quercus sadleriana Quercus havardii, Quercus laceyi Quercus oglethorpensis, Quercus similis Quercus cedrosensis C.H.Müll. Synonyms: Quercus sedrosensis C.H.Müll. Common Names: Cedros Island oak Species profile co-authors: Duncan Bell, Rancho Santa Ana Botanic Garden; Cheryl Birker, Rancho Santa Ana Botanic Garden Contributors: Jon Rebman, San Diego Natural History Museum, Botany Suggested citation: Beckman, E., Bell, D., Birker, C., Meyer, A., & Westwood, M. (2019). Quercus cedrosensis C.H.Müll. In Beckman, E., Meyer, A., Man, G., Pivorunas, D., Denvir, A., Gill, D., Shaw, K., & Westwood, M. Conservation Gap Analysis of Native U.S. Oaks (pp. 86-91). Lisle, IL: The Morton Arboretum. Retrieved from https://www.mortonarb.org/files/species-profile-quercus-cedrosensis.pdf Jon Rebman Figure 1. County-level distribution map for the U.S. distribution of Quercus cedrosensis. Source: Biota of North America Program (BONAP).3 DISTRIBUTION AND ECOLOGY Quercus cedrosensis, or Cedros Island oak, is distributed across Baja California, Mexico, and extends slightly into southern California, U.S. One unverified occurrence is located further south, across the border into Baja California Sur, Mexico. Most populations are concentrated in the northern half of the Baja Peninsula and on Cedros Island, located off the western coast of the peninsula. Recent discoveries have also documented a small but significant population near the Otay Mountains in southwestern San Diego County. Soil preferences likely restrict the distribution of Q. cedrosensis, though more research is necessary to determine its specific range of tolerance (J. Rebman pers comm., 2018). Other shrubs and trees coexisting in this chaparral habitat are evergreens with leaves that Figure 2. Documented in situ occurrence points for the U.S. are thick, leathery, and small. Cedros Island oak is shrubby and very distribution of Quercus cedrosensis. Protected areas layer from U.S. occasionally reaches a maximum of five meters in height. The Geological Survey Gap Analysis Program (GAP) 2016 Protected species tolerates a wide range of elevation, from 75 to 1,400 meters Areas Database of the U.S. (PAD-US).4 above sea level.1,2 86 Conservation Gap Analysis of Native U.S. Oaks Quercus cedrosensis VULNERABILITY OF WILD POPULATIONS Table 1.Scoring matrix identifying the most severe demographic issues affecting Quercus cedrosensis. Cells are highlighted when the species meets the respective vulnerability threshold for each demographic indicator. Average vulnerability score is calculated using only those demographic indicators with sufficient data (i.e., excluding unknown indicators). Level of vulnerability Demographic indicators Emergency High Moderate Low None Unknown Score Score = 40 Score = 20 Score = 10 Score = 5 Score = 0 No score Population size < 50 < 250 < 2,500 < 10,000 > 10,000 Unknown 5 Range/endemism Extremely small range EOO < 100 km2 or EOO < 5,000 km2 or EOO < 20,000 km2 EOO > 20,000 km2 or Unknown 5 or 1 location AOO < 10 km2 or AOO < 500 km2 or 5-9 or AOO < 2,000 km2 AOO > 2,000 km2 2-4 locations locations or 10+ locations Population decline Extreme >= 80% decline >= 50% decline >= 30% decline None Unknown 10 Fragmentation Severe fragmentation Isolated populations Somewhat isolated Relatively connected Connected Unknown 10 populations populations populations Regeneration/ No regeneration or Decline of >50% Insufficient to maintain Sufficient to maintain Sufficient to increase Unknown - recruitment recruitment predicted in next current population size current population size population size generation Genetic variation/ Extremely low Low Medium High Very high Unknown 10 integrity Average vulnerability score 8.0 Rank relative to all U.S. oak species of concern (out of 19) 12 TTHREATS TO WILD POPULATIONS Moderate Impact Threats High Impact Threats Human modification of natural systems — disturbance regime modification, pollution, and/or eradication: There is evidence of Human use of landscape — agriculture, silviculture, ranching, a burn around 2003 within the U.S. population of Q. cedrosensis, and/or grazing: Grazing is a significant issue on the mainland, and the native vegetation seems to be struggling to recover.5 especially within Southern California Dry Mesic Chaparral, which is dominated by Q. cedrosensis, Malosma laurina, and Lotus Human modification of natural systems — invasive species scoparius.5 Goats were introduced on Cedros Island in the competition: Cedros Island oak habitat in the U.S. is “of moderate nineteenth century, but introduced wild dogs kept their numbers low, to poor quality,” with some invasive plant species. Footpaths and reducing their impact.6 grazing activities have facilitated the spread of invasive plants, which further hinder fire recovery.5 Human use of landscape — residential/commercial development, mining, and/or roads: Quercus cedrosensis is affected by land use Genetic material loss — inbreeding and/or introgression: There changes including road construction, border patrol activities, and both is concern that mainland populations are facing threats of urban and rural development. In 2007, the Customs and Border Patrol introgression, as leaf morphology begins to shift.2 Agency proposed to “construct, operate, and maintain tactical infrastructure consisting of primary pedestrian fence and associated Low Impact Threats patrol roads, and access roads along two discrete areas of the U.S./Mexico international border” in San Diego County.7 Similar border Climate change — habitat shifting, drought, temperature safety projects continue today. In Baja California, more than 120,000 extremes, and/or flooding: Drought has lead to a slow recovery acres have been lost to urbanization, agriculture, and rural residential from the 2003 fire.5 development in the past ten years.8 Quercus cedrosensis Conservation Gap Analysis of Native U.S. Oaks 87 CONSERVATION ACTIVITIES A spatial analysis was conducted to estimate the geographic and ecological coverage of ex situ collections (Figure 4). Only the native In 2017 Quercus accessions data were requested from ex situ U.S. distribution of the species was considered in this analysis, due collections. A total of 162 institutions from 26 countries submitted data to availability of ecoregion maps. Fifty-kilometer buffers were placed for native U.S. oaks (Figure 3). Past, present, and planned conservation around each in situ occurrence point and the source locality of each activities for U.S. oak species of concern were also examined through plant living in ex situ collections. Collectively, the in situ buffer area literature review, expert consultation, and conduction of a serves as the inferred native range of the species, or “combined area questionnaire. Questionnaire respondents totaled 328 individuals from in situ” (CAI50). The ex situ buffer area represents the native range 252 organizations, including 78 institutions reporting on species of “captured” in ex situ collections, or “combined area ex situ” (CAE50). concern (Figure 5). Geographic coverage of ex situ collections was estimated by dividing CAI50 by CAE50. Ecological coverage was estimated by dividing Results of 2017 ex situ survey the number of EPA Level IV Ecoregions present in CAE50 by the Number of ex situ collections reporting this species: 1 number of ecoregions in CAI50. Number of plants in ex situ collections: 1 Average number of plants per institution: 1 Estimated ex situ representation Percent of ex situ plants of wild origin: 100% Geographic coverage: 0% Percent of wild origin plants with known locality: 100% Ecological coverage: 0% 5 Coordinates provided Geolocated with locality notes 4 Geolocated to countryU centroid Location data unknown 3 2 Number of plants 1 0 W/Z H Provenance type Figure 3. Number and origin of Quercus cedrosensis plants in ex situ collections. Provenance types: W = wild; Z = indirect wild; H = horticultural; U = unknown. Jon Rebman Figure 4. Quercus cedrosensis in situ occurrence points and ex situ collection source localities within the United States. U.S. EPA Level IV Ecoregions are colored and labelled.9 County centroid is shown if no precise locality data exist for that county of occurrence. Email [email protected] for more information regarding specific coordinates. 88 Conservation Gap Analysis of Native U.S. Oaks Quercus cedrosensis Land protection/ acquistion Habitat management Long term population monitoring Surveying Collect wild germplasm Share germplasm Propagate germplasm Conservation action category Reintroduction/ translocation Conservation genetics research Education/ outreach/training 0 2 4 6 8 10 12 Number of institutions undertaking