Photo Credit: Mark Dodero, RECON
| Historically present | |
| Currently present | |
| Currently not detected |
Goal: Maintain or enhance existing Thread-leaved brodiaea occurrences to ensure multiple conserved occurrences with self sustaining populations to increase resilience to environmental and demographic stochasticity, maintain genetic diversity, and ensure persistence over the long term (>100 years) in grassland and vernal pool vegetation communities.
Management units: 6, 7, 8
Beginning in 2017, inspect conserved populations of thread-leaved brodiaea in (see occurrence table) using the regional rare plant IMG monitoring protocol to record abundance and collect covariate habitat and threats data to determine management needs. After 2017, repeat monitoring every 2 years.
| Action | Statement | Action status | Projects |
|---|---|---|---|
| IMP-1 | Based upon occurrence status and threats, determine management needs including whether routine management or more intensive management is warranted. | some occurrences are in progress | |
| IMP-2 | Submit project metadata, monitoring datasets and management recommendations to the MSP Web Portal. | some occurrences are in progress |
| Criteria | Deadline year |
|---|---|
| Surveys Completed Every 2 Years with Management Recommendations | 2021 |
| Threat Name | Threat Code |
|---|---|
| Human uses of the Preserves | HUMUSE |
| Invasive plants | INVPLA |
| Urban development | URBDEV |
Management units: 6, 7, 8
Beginning in 2017, conduct routine management actions identified through the IMG monitoring at thread-leaved brodiaea occurrences on Conserved Lands (see occurrence table). Depending on the type and level of threat, management should only be conducted as needed, not necessarily every year, and using BMPs with precautions to do no harm.
| Criteria | Deadline year |
|---|---|
| Routine Management Completed as Needed Based Upon Monitoring Recommendations | 2021 |
| Threat Name | Threat Code |
|---|---|
| Human uses of the Preserves | HUMUSE |
| Invasive plants | INVPLA |
| Urban development | URBDEV |
Management units: 6, 7, 8
In 2017, continue field research into soils and habitat relationships and development of habitat suitability and climate change models for thread-leaved brodiaea and other edaphic endemic plants to better understand habitat requirements and to identify and prioritize geographic areas important for connectivity, restoration, and range shifts due to climate change and other threats.
| Action | Statement | Action status | Projects |
|---|---|---|---|
| RES-1 | Test soils at potential expansion sites and compare to occupied reference sites to determine site suitability based on soils. | In progress | Enhancing the Resilience of Edaphic Endemic Plants |
| RES-2 | Prepare habitat suitability models under current environmental conditions and for different scenarios of climate change to delineate potential future habitat. | In progress | Enhancing the Resilience of Edaphic Endemic Plants |
| RES-3 | Collect covariate data on vegetation composition and cover (alliance and association-level mapping), soils, invasive plants and other threats for selected populations. | In progress | Enhancing the Resilience of Edaphic Endemic Plants |
| RES-4 | Prioritize locations for conservation, management, and future surveys based on predicted distributions and environmental correlates. | In progress | Enhancing the Resilience of Edaphic Endemic Plants |
| RES-5 | Submit project metadata, monitoring data and report to MSP web portal. | In progress | Enhancing the Resilience of Edaphic Endemic Plants |
| Criteria | Deadline year |
|---|---|
| Refined Models and Prioritized Future Survey Locations for thread-leaved brodiaea by 2018 | 2021 |
| Threat Name | Threat Code |
|---|---|
| Climate change | CLICHN |
| Invasive plants | INVPLA |
| Loss of connectivity | LOSCON |
| Urban development | URBDEV |
Management units: 6, 7, 8
In 2019, survey historic thread-leaved brodiaea locations to determine occurrence status; survey and delineate potentially suitable habitat for new occurrences; survey existing occurrences to identify the potential for enhancement and expansion; and at all sites collect data on occurrence status, habitat and threats and determine management needs.
| Action | Statement | Action status | Projects |
|---|---|---|---|
| SURV-1 | At each extant occurrence, map the extent of the occurrence, collect data on abundance, map adjacent suitable habitat for potential occurrence expansion, collect covariate data on threats including estimates of cover of invasive non-native plants and trampling. | On hold | |
| SURV-2 | Submit project metadata, occurrence status, habitat mapping and assessment, and report to the MSP Web Portal. | On hold |
| Criteria | Deadline year |
|---|---|
| Surveys and Report Completed by 2020 | 2021 |
| Threat Name | Threat Code |
|---|---|
| Climate change | CLICHN |
| Human uses of the Preserves | HUMUSE |
| Invasive plants | INVPLA |
| Loss of connectivity | LOSCON |
| Urban development | URBDEV |
Management units: 6, 7, 8
In 2020, begin preparing a section for thread-leaved brodiaea in the MSP Rare Plant Management Plan that prioritizes management actions to maintain and expand conserved occurrences (see occurrence table) based upon an assessment of data on occurrence status, habitat and threats. Prioritize management recommendations for re-establishment of historic occurrences or establishment of new occurrences in suitable habitat, as needed, to achieve at least 4 occurrences with self-sustaining populations on Conserved Lands. Minimum criteria for enhancement are to reduce invasive annual nonnative plants and thatch to less than 20% absolute cover within the occurrence.
| Action | Statement | Action status | Projects |
|---|---|---|---|
| PRP-1 | Prioritize extant occurrences for management based upon "IMG" monitoring data and baseline survey assessments of occurrence size, the potential for management to significantly reduce identified threats, and the availability of adjacent suitable habitat for occurrence expansion. | some occurrences are in progress | |
| PRP-2 | Develop a conceptual model that identifies management actions to effectively reduce threats to thread-leaved brodiaea occurrences. | some occurrences are in progress | |
| PRP-3 | Identify and prioritize sites for re-establishment of historic occurrences or that appear suitable for establishment of new occurrences. Specify the highest priority sites for establishing occurrences on Conserved Lands. | some occurrences are in progress | |
| PRP-4 | Develop an implementation plan for thread-leaved brodiaea that prioritizes management actions for the next 5 years and details tasks, lead entities, responsibilities, and timelines, budgets. | some occurrences are in progress | |
| PRP-5 | Submit project metadata and MSP Rare Plant Management Plan to MSP Web Portal. | some occurrences are in progress |
| Criteria | Deadline year |
|---|---|
| By 2021, Completed Section for Thread-leaved brodiaea in the MSP Rare Plant Management Plan | 2021 |
| Threat Name | Threat Code |
|---|---|
| Climate change | CLICHN |
| Human uses of the Preserves | HUMUSE |
| Invasive plants | INVPLA |
| Loss of connectivity | LOSCON |
| Urban development | URBDEV |
Management units: 6, 7, 8
Beginning in 2021, begin implementing highest priority management actions identified in the thread-leaved brodiaea section of the MSP Rare Plant Management Plan.
| Action | Statement | Action status | Projects |
|---|---|---|---|
| IMP-1 | Submit project metadata, management datasets, and report to the MSP Web Portal. | waiting for precedent action |
| Criteria | Deadline year |
|---|---|
| By 2025, =1 High priority Management Action Implemented for Thread-leaved Brodiaea from the MSP Rare Plant Management Plan | 2021 |
| Threat Name | Threat Code |
|---|---|
| Climate change | CLICHN |
| Human uses of the Preserves | HUMUSE |
| Invasive plants | INVPLA |
| Loss of connectivity | LOSCON |
| Urban development | URBDEV |
Management units: 6, 7, 8
Monitor effectiveness of implementation of highest priority management actions identified in the thread-leaved brodiaea section in the MSP Rare Plant Management Plan.
| Action | Statement | Action status | Projects |
|---|---|---|---|
| IMP-1 | Submit metadata, management effectiveness datasets, analyses, and report to the MSP Web Portal. | waiting for precedent action |
| Criteria | Deadline year |
|---|---|
| Effectiveness of High Priority Management Actions Determined | 2021 |
| Threat Name | Threat Code |
|---|---|
| Climate change | CLICHN |
| Human uses of the Preserves | HUMUSE |
| Invasive plants | INVPLA |
| Loss of connectivity | LOSCON |
| Urban development | URBDEV |
Management units: 6, 7, 8
In 2020, begin preparing a section for Thread-leaved brodiaea in the MSP Seed Collection, Banking and Bulking Plan to preserve genetic diversity and rescue occurrences in case of catastrophic disturbance. The plan should incorporate best science and management practices (Wall 2009, KEW 2016) and recommendations from the genetic study to provide guidelines for collecting and storing seeds over the long term at a permanent, established conservation seed bank (e.g., Institute for Conservation Research Native Plant Seed Bank, Rancho Santa Ana Botanic Garden Seed Conservation Program) and for providing seed sources for management purposes. The plan should include recommendations for: collecting and storing seeds for conservation banking; management oriented research; rescuing occurrences after catastrophic disturbances; and seed bulking and out-planting to augment extant occurrences or to establish new occurrences with consideration of genetic implications for population sustainability.
| Action | Statement | Action status | Projects |
|---|---|---|---|
| PRP-1 | Consult the San Diego County Rare Plant Working Group made up of plant ecologists, geneticists, rare plant experts, land managers, restoration practitioners, seed banking and bulking practitioners, wildlife agencies, and other stakeholders to provide input and recommendations for the Thread-leaved brodiaea MSP Seed Collection, Banking and Bulking Plan. | some occurrences are in progress | |
| PRP-2 | Design a seed collection plan to collect seeds over multiple years, collect seeds several times within a season, accumulate seeds across populations, and to sample among habitats and ecological niches. Include guidelines for collecting and storing seeds along maternal lines from small occurrences (<1,000 plants) and to provide propagules to be used in management experiments, enhancement of existing occurrences, and establishment of new occurrences. | some occurrences are in progress | |
| PRP-3 | The seed collection plan should include guidelines for collecting seeds from occurrences of sufficient size to accommodate harvest and based on genetic studies as available. Include provisions for collecting seed from unconserved populations planned for development. | some occurrences are in progress | |
| PRP-4 | Include protocols and guidelines for collecting voucher specimens and submitting to the San Diego Natural History Museum (McEachern et al. 2007). | some occurrences are in progress | |
| PRP-5 | Include guidelines for testing seeds for viability and to obtain information on dormancy and germination rates. | waiting for precedent action |
| Criteria | Deadline year |
|---|---|
| By 2021, completed section for Thread-leaved brodiaea in the MSP Seed Collection, Banking and Bulking Plan | 2021 |
| Threat Name | Threat Code |
|---|---|
| Climate change | CLICHN |
| Human uses of the Preserves | HUMUSE |
| Invasive plants | INVPLA |
| Loss of connectivity | LOSCON |
| Urban development | URBDEV |
Management units: 6, 7, 8
In 2021, begin implementing the MSP Seed Collection, Banking and Bulking Plan for Thread-leaved brodiaea to collect and store seeds at a permanent seed bank and to provide propagules as needed for management oriented research, existing population enhancement and establishment of new occurrences
| Action | Statement | Action status | Projects |
|---|---|---|---|
| IMP-1 | Seed should be stored for conservation banking and as source of propagules for enhancement and restoration projects at a permanent, established seed bank. | waiting for precedent action | |
| IMP-2 | Submit project metadata and Thread-leaved brodiaea MSP Seed Collection, Banking and Bulking Plan to the MSP Web Portal. | waiting for precedent action |
| Criteria | Deadline year |
|---|---|
| By 2025, =1 Highest Priority Action Implemented for Thread-leaved brodiaea from the MSP Seed Banking and Bulking Plan | 2021 |
| Threat Name | Threat Code |
|---|---|
| Human uses of the Preserves | HUMUSE |
| Invasive plants | INVPLA |
| Loss of connectivity | LOSCON |
| Urban development | URBDEV |
|
Enhancing the Resilience of Edaphic Endemic Plants
The Management Strategic Plan for San Diego County requires prioritization and management for edaphic endemic plants, including the five rare plants addressed in this study. These species face low genetic diversity due to reduced population sizes, geographic isolation, and loss of pollinators. To enhance the resilience of these species across their ranges, we must manage threats to increase population sizes, identify potentially suitable habitat to connect existing populations, find or restore new populations, and provide opportunities for shifting distributions due to climate change.
This study identifies and describes geographic areas that support the five edaphic endemic species and their habitat in a design that enhances resilience and provides opportunities for shifting distributions. We developed conceptual models to inform field studies and management, refined soils and vegetation attributes, and assessed regional population structure and threats. We used results to suggest prioritized locations for surveys, management, potential translocation, and additional conservation or acquisition. Project partners (U.S. Geological Survey and San Diego Management and Monitoring Program) modeled suitable habitat for the target species under current and future climate scenarios; we reference models as appropriate.
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Rare Plant Inspect and Manage Monitoring 2014-2026
From 2014-2026, a Management and Monitoring Strategic Plan (MSP Roadmap) monitoring objective for 30 rare plant species is to inspect occurrences to determine management needs. The inspect and manage (IMG) objective is implemented to document the status of rare plant occurrences and assess habitats and threats to develop specific management recommendations. IMG monitoring is implemented by a combination of land managers and contracted biologists in coordination with the SDMMP. Available rare plant data is posted below. New annual updates are typically posted in March. Based upon an evaluation of these data, a 2014-2026 monitoring schedule has been developed for the 30 rare plant species (attached below). Coordinating data collection across the region allows analyses of species and population trends over time and provides a better understanding of the association between habitat and threat covariates and population dynamics.
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From the foothills of the San Gabriel Mountains at Glendora (Los Angeles County), east to Arrowhead Hot Springs in the western foothills of the San Bernardino Mountains (San Bernardino County), and south through eastern Orange and western Riverside Counties to Rancho Santa Fe in central coastal San Diego County, California [1].
Twenty occurrences on Conserved Lands in MUs 6 (Black Mountain Open Space Park, Buena Vista Creek Ecological Reserve, Carlsbad Highlands Ecological Reserve, Carlsbad Oaks North Habitat Conservation Area, Lake Calavera Municipal Mitigation Parcel, Letter Box Canyon-Fox Miller Brodiaea Preserve, Rancho La Costa Habitat Conservation Area) and 7 (Cleveland National Forest).
FT and CE [2].
Typically occurs on gentle hillsides, valleys, and floodplains in mesic, southern needlegrass grassland and alkali grassland plant communities in association with clay, loamy sand, or alkaline silty-clay soils [3]. Occurrences may be intermixed with, or near, vernal pool complexes [4, 5; both cited in 3]. Usually found in herbaceous plant communities such as valley needlegrass grassland, valley sacaton grassland, nonnative grassland, alkali playa, southern interior basalt vernal pools, San Diego mesa hardpan vernal pools, and San Diego mesa claypan vernal pools [6]. Elevation range is 25-1120 meters [2].
Now member of the Lilaceae family; formerly Themidaceae [1]. Hybrids exist within the range of B. filifolia at Miller Mountain and Devil Canyon in northwestern San Diego County [7, 8]. Parent taxa of hybrids considered to be B. filifolia and B. orcuttii because of the morphological intermediacy and proximity of their ranges [1].
Perennial bulbiferous herb [1].
Flowering period March-June [2]. Seeds mature in late spring and early summer.
Upon maturity, the 3 segments of the vertically oriented capsules split apart, revealing many small (2 to 2.5 millimeters long) black seeds [9; cited in 3]. Seeds are then dispersed by wind [10]. Released seeds fall to the ground, either on the surfaces or into the cracks in the soil [1]. Self-incompatible, so pollination between individuals must take place in order to produce seed [11]. Dispersal of seeds from an individual is likely localized, leading to patches of plants with the same self-incompatible alleles [1]. This means that effective pollination for seed set requires pollen dispersal over a distance between plants with different self-incompatible alleles. Members of the genus Brodiaea reportedly rely on Tumbling Flower Beetles (Mordellidae, Coleoptera) and Sweat Bees (Halictidae, Hymenoptera) for cross-pollination [11]. Native bees observed pollinating on the Santa Rosa Plateau in Riverside County included Bombus californicus (Apidae, Hymenoptera), Hoplitus sp. (Megachilidae, Hymenoptera), Osmia sp. (Megachilidae, Hymenoptera), and an unidentified Anthophorid (digger-bee) [12; cited in 3]. Anthophoridae and Halictidae are reported to be important pollinators of B. filifolia at a study site in Orange County [13; cited in 8].
Loss of habitat from urbanization and agricultural conversion are significant threats [14]. Other threats include alteration of hydrology and minimal impacts from livestock grazing, primarily in Riverside and Orange Counties; unauthorized off-highway vehicles; discing for fire suppression, and competition from nonnative plants [1]. Mowing may reduce the production and dispersal of seeds, alter the associated vegetation needed for pollinator activity, or reduce the number and vigor of plants present by cutting off the leaves [8]. The 19 occurrences on Camp Pendleton are protected from development, but are still vulnerable to impacts from military-related activities, and nonnative plants [1]. Cyclic drought, a possible outcome of climate change in the region, reduces local populations over the long term.
Camp Pendleton has an Integrated Natural Resource Management Plan that includes conservation measures for B. filifolia [1]. The City of Carlsbad’s HMP under the Northwestern San Diego County MHCP and the Villages of La Costa HCP both include B. filifolia as a covered species. Results from the Center for Natural Lands Management's 2009 study shows that the grass specific herbicide, Fusilade II, does not appear to kill or harm B. filifolia [15]. Additionally, there appears to be a positive effect on flowering production post-herbicide treatment .
[1] CNDDB (California Department of Fish and Game Natural Diversity Data Base). 2007. “Element Occurrence Reports for Brodiaea Filifolia. Unpublished Cumulative Data.â€
[2] CNPS, Rare Plant Program. 2016. Inventory of Rare and Endangered Plants (online edition, v8-02). California Native Plant Society, Sacramento, CA. http://www.rareplants.cnps.org, accessed 30 August 2016.
[3] U.S. Fish and Wildlife Service. 2009. "Brodiaea filifolia (thread-leaved brodiaea) 5-Year Review Summary and Evaluation U . S . Fish and Wildlife Service". Carlsbad, California.
[4] California Department of Fish and Game. 1981. “Brodiaea Filifolia. California State Endangered Plant Program. Unpublished Report.â€
[5] Bramlet, D. 1993. “Plant Species of Special Concern in the Alkaline Sinks of the San Jacinto River and the Old Salt Creek Tributary Area. Unpublished Report.â€
[6] Holland, R. F. 1986. “Preliminary Descriptions of the Terrestrial Natural Communities of California.†Sacramento, CA. ftp://ftp.conservation.ca.gov/pub/oil/SB4DEIR/docs/BIOT_Holland_1986.pdf.
[7] U.S. Fish and Wildlife Service. 2004. "Endangered and threatened wildlife and plants; proposed designation of critical habitat for Brodiaea filifolia (thread-leaved brodiaea)". Federal Register, 69, 71284–71319.
[8] U.S. Fish and Wildlife Service. 2005. "Designation of critical habitat for Brodiaea filifolia (thread-leaved brodiaea)". Federal Register, 70, 73820–73856.
[9] Munz, P. A. 1974. A flora of southern California. Berkeley, California: UC Press.
[10] Smith, N. 1997. “Growing Natives: Brodiaeas-Part I.†Fremontia 25 (4): 28–30.
[11] Niehaus, T.F. 1971. “A Biosystematic Study of the Genus Brodiaea (Amaryllidaceae).†U.C. Publications in Botany 60 (1): 1–66.
[12] Bell, G.P., and E.M. Rey. 1991. “The Biology of Three Species of Brodiaea (Amaryllidacaea) on the Santa Rosa Plateau (Riverside County). Contract #FG-8589. Preliminary Report Submitted to the Natural Heritage Division, California Department of Fish and Game.â€
[13] Glen Lukas Associates Inc. 2004. “First Annual Monitoring Report for Brodiaea filifolia Pollination Monitoring Associated with Arroyo Trabuco Golf Course, Mission Viejo, California. Unpublished Report Submitted to the U.S. Fish and Wildlife Service.â€
[14] U.S. Fish and Wildlife Service. 1998. “Endangered and Threatened Wildlife and Plants; Determination of Endangered or Threatened Status for Four Southwestern California Plants from Vernal Wetlands and Clay Soils.†Federal Register 36: 54975–94.
[15] Vinje, J., P. McConnell, and M. Spiegelberg. 2009. “2009 Progress Report for the Herbicide Application of Fusilade II to Thread-Leaved Brodiaea ( Brodiaea Filifolia ).†Fallbrook, CA.