Basic Information
Common Name: Dehesa Nolina
Scientific Name: Nolina interrata
Species Code: NOLINT
Management Category: SO (significant occurrence at risk of loss)
Occurrence Map
Table of Occurrences
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Species Information

MSP Species Background

Goals and Objectives

Goal: Maintain or enhance existing Dehesa beargrass occurrences and establish new occurrences, as needed, 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 chaparral vegetation communities.

regional and/or local NFO 2017 SO
MON-IMP-IMG NOLINT-1

Management units: 3

Beginning in 2017 and continuing every 5 years, thereafter, continue inspections of Dehesa beargrass occurrences on Conserved Lands (see occurrence table) begun in 2014 using the IMG regional monitoring protocol to record abundance/map perimeters and collect threats and covariate data to determine management needs.

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. in progress
IMP-2 Submit project metadata, monitoring datasets and management recommendations to the MSP Web Portal. in progress
Criteria Deadline year
Surveys Completed in 2017 with Management Recommendations 2021
Threat Name Threat Code
Altered fire regimeALTFIR
Climate changeCLICHN
Invasive plantsINVPLA
Loss of connectivityLOSCON
Code Obj. code Statement
NOLINT-2 MGT-IMP-IMG Beginning in 2017, conduct routine management actions begun in 2014 identified through the IMG regional protocol monitoring on Conserved Lands. 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.
NOLINT-4 MGT-PRP-MGTPL In 2019, begin preparing a section for Dehesa nolina in the MSP Rare Plant Management Plan that prioritizes management actions to maintain or expand conserved occurrences based upon an assessment of data on occurrence status habitat and threats. Minimum criteria for enhancement are to reduce invasive annual nonnative plants and thatch to less than 20% absolute cover within the occurrence
NOLINT-6 MON-IMP-MGTPL Monitor the effectiveness of highest priority management actions identified in the Rare Plant Management Plan for Dehesa nolina.
local NFO 2017, 2018, 2019, 2020, 2021 SO
MGT-IMP-IMG NOLINT-2

Management units: 3

Beginning in 2017, conduct routine management actions begun in 2014 identified through the IMG regional protocol monitoring on Conserved Lands. 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.

Action Statement Action status Projects
IMP-1 Perform routine management activities such as protecting occurrences from disturbance through fencing and enforcement and controlling invasive non-native plant species to less than 20% relative cover. some occurrences are in progress
IMP-2 Submit project metadata and management data to the MSP Web Portal. some occurrences are in progress
Criteria Deadline year
Routine Management Completed as Needed Based Upon Monitoring Recommendations 2021
Threat Name Threat Code
Altered fire regimeALTFIR
Climate changeCLICHN
Invasive plantsINVPLA
Loss of connectivityLOSCON
Code Obj. code Statement
NOLINT-1 MON-IMP-IMG Beginning in 2017 and continuing every 5 years, thereafter, continue inspections of Dehesa beargrass occurrences on Conserved Lands (see occurrence table) begun in 2014 using the IMG regional monitoring protocol to record abundance/map perimeters and collect threats and covariate data to determine management needs.
Regional and/or Local NFO 2017 SO
MGT-DEV-BMP NOLINT-3

Management units: 3

By 2017, refine BMPs for Dehesa beargrass based on results of experimental management studies currently in progress, as well as research studies. Submit all data and reports to MSP web portal.

Action Statement Action status Projects
DEV-1 Refine BMPs by incorporating results of management experiments to control invasive species that threaten Dehesa beargrass populations in San Diego County (e.g., Brachypodium removal project). In progress
DEV-2 Submit project metadata, monitoring data, reports and management recommendations to MSP web portal. In progress
Criteria Deadline year
BMPs for Dehesa Beargrass Completed by 2018 2021
Threat Name Threat Code
Altered fire regimeALTFIR
Climate changeCLICHN
Invasive plantsINVPLA
Loss of connectivityLOSCON
Code Obj. code Statement
NOLINT-4 MGT-PRP-MGTPL In 2019, begin preparing a section for Dehesa nolina in the MSP Rare Plant Management Plan that prioritizes management actions to maintain or expand conserved occurrences based upon an assessment of data on occurrence status habitat and threats. Minimum criteria for enhancement are to reduce invasive annual nonnative plants and thatch to less than 20% absolute cover within the occurrence
regional NFO 2019 SO
MGT-PRP-MGTPL NOLINT-4

Management units: 3

In 2019, begin preparing a section for Dehesa nolina in the MSP Rare Plant Management Plan that prioritizes management actions to maintain or expand conserved occurrences based upon an assessment of data on occurrence status habitat and threats. 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 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 Dehesa nolina in the Rare Plant Management Plan. on hold
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 Dehesa nolina in the Rare Plant Management Plan. on hold
PRP-2 Develop a conceptual model that identifies management actions to effectively reduce threats to Dehesa nolina populations. on hold
PRP-3 Prioritize occurrences for management based upon an assessment of occurrence status, the potential for management to significantly reduce identified threats, and the availability of adjacent suitable habitat for occurrence expansion. on hold
PRP-4 Develop an implementation plan for Dehesa beargrass that prioritizes management actions for the next 5 years and details tasks, lead entities, responsibilities, and timelines, budgets. on hold
PRP-5 Submit project metadata and MSP Rare Plant Management Plan to the MSP Web Portal. on hold
Criteria Deadline year
By 2020, Completed Dehesa Nolina Section in the MSP Rare Plant Management Plan 2021
Threat Name Threat Code
Altered fire regimeALTFIR
Climate changeCLICHN
Invasive plantsINVPLA
Loss of connectivityLOSCON
Code Obj. code Statement
NOLINT-1 MON-IMP-IMG Beginning in 2017 and continuing every 5 years, thereafter, continue inspections of Dehesa beargrass occurrences on Conserved Lands (see occurrence table) begun in 2014 using the IMG regional monitoring protocol to record abundance/map perimeters and collect threats and covariate data to determine management needs.
NOLINT-2 MGT-IMP-IMG Beginning in 2017, conduct routine management actions begun in 2014 identified through the IMG regional protocol monitoring on Conserved Lands. 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.
NOLINT-3 MGT-DEV-BMP By 2017, refine BMPs for Dehesa beargrass based on results of experimental management studies currently in progress, as well as research studies. Submit all data and reports to MSP web portal.
NOLINT-4 MGT-PRP-MGTPL In 2019, begin preparing a section for Dehesa nolina in the MSP Rare Plant Management Plan that prioritizes management actions to maintain or expand conserved occurrences based upon an assessment of data on occurrence status habitat and threats. Minimum criteria for enhancement are to reduce invasive annual nonnative plants and thatch to less than 20% absolute cover within the occurrence
NOLINT-5 MGT-IMP-MGTPL Beginning in 2020, implement highest priority management actions identified in the Dehesa nolina section of the MSP Rare Plant Management Plan.
NOLINT-7 MGT-PRP-SBPL In 2019, begin preparing a section for Dehesa nolina 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 (e.g., Wall 2009, KEW 2016) and 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 a source of seeds 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.
NOLINT-9 MON-RES-SPEC In 2017, begin field research into soils and habitat relationships and conduct habitat suitability and climate change modeling for Dehesa nolina 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.
Regional and/or Local NFO 2020, 2021 SO
MGT-IMP-MGTPL NOLINT-5

Management units: 3

Beginning in 2020, implement highest priority management actions identified in the Dehesa nolina section of the MSP Rare Plant Management Plan.

Action Statement Action status Projects
IMP-1 Implement site-specific invasive control management actions for a minimum of 3 years to reduce invasive nonnative plants to =20% absolute cover in Dehesa nolina suitable habitat based onthe Dehesa nolina Management Plan, and results from BMP studies (e.g., Brachypodium removal project). Actions may include thatch removal and invasives control using herbicide or mechanical methods. waiting for precedent action
IMP-2 Based on the response of Dehesa nolina to initial management actions, determine need for (1) further invasives control and (2) additional habitat enhancement such as seeding of additional native plant species that support pollinator communities or facilitate sustainable Dehesa nolina populations by inhibiting germination and growth of invasive species. waiting for precedent action
IMP-3 Submit project metadata, reports and management recommendations to MSP web portal. waiting for precedent action
Criteria Deadline year
By 2024, =1 High Priority Management Action Implemented for Dehesa Nolina from the MSP Rare Plant Management Plan 2021
Threat Name Threat Code
Altered fire regimeALTFIR
Climate changeCLICHN
Invasive plantsINVPLA
Loss of connectivityLOSCON
Code Obj. code Statement
NOLINT-2 MGT-IMP-IMG Beginning in 2017, conduct routine management actions begun in 2014 identified through the IMG regional protocol monitoring on Conserved Lands. 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.
NOLINT-4 MGT-PRP-MGTPL In 2019, begin preparing a section for Dehesa nolina in the MSP Rare Plant Management Plan that prioritizes management actions to maintain or expand conserved occurrences based upon an assessment of data on occurrence status habitat and threats. Minimum criteria for enhancement are to reduce invasive annual nonnative plants and thatch to less than 20% absolute cover within the occurrence
Local NFO 2020, 2021 SO
MON-IMP-MGTPL NOLINT-6

Management units: 3

Monitor the effectiveness of highest priority management actions identified in the Rare Plant Management Plan for Dehesa nolina.

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
Altered fire regimeALTFIR
Climate changeCLICHN
Invasive plantsINVPLA
Loss of connectivityLOSCON
Code Obj. code Statement
NOLINT-4 MGT-PRP-MGTPL In 2019, begin preparing a section for Dehesa nolina in the MSP Rare Plant Management Plan that prioritizes management actions to maintain or expand conserved occurrences based upon an assessment of data on occurrence status habitat and threats. Minimum criteria for enhancement are to reduce invasive annual nonnative plants and thatch to less than 20% absolute cover within the occurrence
NOLINT-5 MGT-IMP-MGTPL Beginning in 2020, implement highest priority management actions identified in the Dehesa nolina section of the MSP Rare Plant Management Plan.
Regional NFO 2019 SO
MGT-PRP-SBPL NOLINT-7

Management units: 3

In 2019, begin preparing a section for Dehesa nolina 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 (e.g., Wall 2009, KEW 2016) and 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 a source of seeds 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 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 Dehesa nolina in the MSP Seed Collection, Banking and Bulking Plan. some occurrences are in progress
PRP-2 Prepare 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. some occurrences are in progress
PRP-6 Submit project metadata and MSP Seed Collection, Banking and Bulking Plan to the MSP Web Portal. some occurrences are in progress
Criteria Deadline year
By 2019, Completed Dehesa Nolina Section in MSP Seed Collection, Banking and Bulking Plan 2021
Threat Name Threat Code
Altered fire regimeALTFIR
Climate changeCLICHN
Invasive plantsINVPLA
Loss of connectivityLOSCON
Code Obj. code Statement
NOLINT-1 MON-IMP-IMG Beginning in 2017 and continuing every 5 years, thereafter, continue inspections of Dehesa beargrass occurrences on Conserved Lands (see occurrence table) begun in 2014 using the IMG regional monitoring protocol to record abundance/map perimeters and collect threats and covariate data to determine management needs.
NOLINT-3 MGT-DEV-BMP By 2017, refine BMPs for Dehesa beargrass based on results of experimental management studies currently in progress, as well as research studies. Submit all data and reports to MSP web portal.
NOLINT-4 MGT-PRP-MGTPL In 2019, begin preparing a section for Dehesa nolina in the MSP Rare Plant Management Plan that prioritizes management actions to maintain or expand conserved occurrences based upon an assessment of data on occurrence status habitat and threats. Minimum criteria for enhancement are to reduce invasive annual nonnative plants and thatch to less than 20% absolute cover within the occurrence
NOLINT-8 MGT-IMP-SBPL In 2020, begin implementing high priority actions for Dehesa nolina in the MSP Seed Collection, Banking and Bulking Plan 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.
Regional and/or Local NFO 2020, 2021 SO
MGT-IMP-SBPL NOLINT-8

Management units: 3

In 2020, begin implementing high priority actions for Dehesa nolina in the MSP Seed Collection, Banking and Bulking Plan 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 Bulk seed at a qualified facility for enhancement, expansion, establishment or transplantation projects using seed from genetically appropriate donor accessions in the propagation seed bank collection. waiting for precedent action
IMP-2 Maintain records for collected seed to document donor and receptor sites, collection dates and amounts. Submit seed collection, storage and bulking data to the MSP Web Portal. waiting for precedent action
Criteria Deadline year
Dehesa Nolina Seed Collected for Banking and Bulking Within 2 Years Post-Fire and =1 High Priority Action from the MSP Seed, Collection, Banking and Bulking Plan by 2024 2021
Threat Name Threat Code
Altered fire regimeALTFIR
Climate changeCLICHN
Invasive plantsINVPLA
Loss of connectivityLOSCON
Code Obj. code Statement
NOLINT-6 MON-IMP-MGTPL Monitor the effectiveness of highest priority management actions identified in the Rare Plant Management Plan for Dehesa nolina.
Regional NFO 2017 SO
MON-RES-SPEC NOLINT-9

Management units: 3

In 2017, begin field research into soils and habitat relationships and conduct habitat suitability and climate change modeling for Dehesa nolina 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, habitat models, analyses, 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 Dehesa nolina by 2018 2021
Threat Name Threat Code
Altered fire regimeALTFIR
Climate changeCLICHN
Invasive plantsINVPLA
Loss of connectivityLOSCON
Code Obj. code Statement
NOLINT-1 MON-IMP-IMG Beginning in 2017 and continuing every 5 years, thereafter, continue inspections of Dehesa beargrass occurrences on Conserved Lands (see occurrence table) begun in 2014 using the IMG regional monitoring protocol to record abundance/map perimeters and collect threats and covariate data to determine management needs.
Brachypodium Control - Phase I and II
This project used a science-based, experimental approach to develop treatment and restoration strategies for the emerging invasive grass, Brachypodium distachyon (Brachypodium), on conserved lands in southern San Diego County, CA. Phase I (2013-2015) included conceptual models to inform experimentally-based treatment and restoration strategies; experimental treatments (dethatching, herbicide, mechanical removal), monitoring, and seed collection, bulking, and outplanting. Treatments continued in Phase II (2016-2017), using the most effective management strategy (herbicide). See the Phase I and II reports for study results and Best Management Practices (BMPs) for Brachypodium control. Herbicide is the most effective treatment for controlling Brachypodium but timing of treatment is critical and multiple treatments may be required in a single year, depending on rainfall and temperature. Herbicide treatment of forbs becomes increasingly important as cover of Brachypodium and other nonnative grasses decrease. Dethatching improves treatment effectiveness and stimulates the soil seedbank (if present). The experimental design was coordinated with SDMMP and the City of San Diego, and results may contribute to a regional analysis of Brachypodium control across multiple sites, habitats, and microclimates.
Covered and Invasive Species Management: Crestridge Ecological Reserve and South Crest Properties
This was a two year, TransNet-funded study (#5001586) on Crestridge Ecological Reserve and South Crest properties. Both properties support MSCP covered species and sensitive habitats, and function as critical landscape linkages between the northern and southern MSCP. Surrounded by residential development and heavily impacted by the 2003 Cedar Fire, these properties are subject to ongoing invasive plant issues. Specific task actions included invasive plant and covered plant species mapping and risk assessment s, invasive plant control and experimental studies, and development of an early detection invasive control plan.
Dehesa Nolina Conservation and Management Strategy
The Conservation Biology Institute developed a science-based Conservation Vision and Management Strategy for Dehesa nolina in San Diego County. The Conservation Vision assessed the distribution, status, and threats of populations on conserved lands through data and literature reviews, site visits, and interviews with land managers. Products included spatial data layers, an updated matrix of threats and stressors, management recommendations, and prioritized populations for management. The Management Strategy focused on preserve-level management, using the existing Dehesa nolina population on the South Crest Preserve to test/refine management techniques, including species augmentation (seed collection, contract growing of plants, out-planting) and erosion control. These actions also benefitted Dudleya variegata (variegated dudleya) and sensitive native grassland habitat. These management actions complemented other Transnet-funded management on South Crest; techniques refined in this project are applicable to other conserved populations in the region.
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.

Current Distribution Rangewide

Restricted distribution in southern foothills of San Diego County and northwest Baja California [1). In Baja, three small populations reported between border and Ensenada. Elevation range 230-700m [2). In San Diego, Reiser (1994) reported from Dehesa School, McGinty Peak; Sequan Peak; also Barber Mountain, Jamul Butte, Wood Valley, Pat's Mountain, and on west side of Sloane Canyon on The Mesa. In the MSPA, occurs in MU3 (McGinty Mountain Preserve, San Diego National Wildlife Refuge, South Crest Properties, Sycuan Peak Ecological Reserve; [4]).

List Status

SE; Proposed for federal listing

Habitat Affinities

Typically found in rugged terrain dominated by southern mixed chaparral or chamise chaparral in areas with these nutrient poor clay soils [1,3]. Known only from gabbro substrates (rich in ferro-magnesium minerals; [2]).

Taxonomy and Genetics

Perennial herb; Ruscaceae family [6]. Dice (1988) concluded N. interrata distinct from Parry’s beargrass (N. parryi), Peninsular beargrass (N.cismontana), and Bigelow’s nolina (N. bigelovii) and N. wolfii (N. wolfii reduced to synonomy with N. parryi); referred to these as N. bigelovii- N. parryi complex. Distinguished from the other Nolina in California by lack of aerial stems, rosettes with 45 or fewer finely serrate leaves, flower stalks under 1.6 m tall; distinguished from Yucca species by lack of a rigid spinose (spiny) leaf tip and leaves with shredding margins [1].

Life History Demography

Forms clusters of rosettes and has flower stalks up to 1.6 m tall [1]. Reproduces sexually and asexually (from underground stems; [1]). Nolina can take long period from germination to attain sufficient size for flowering, although two male plants of this species flowered in 3 years or less based on collected seeds [2]. Flowers profusely after fires [1]. Population estimated at ~9,000 plants within the 15.6 km2 range in the U.S. [1]. Morphology helps survival during fire (subterranean buds and above-ground apical buds protected by dense crown of overlapping succulent leaf bases); mass-flowering events observed 1-2 years following fire, although seed predation may diminish productivity from these events [2].

Seasonal Phenology

Blooming period June-July [6].

Pollination Seed Dispersal

Dioecious (separate male and female plants); does not flower every year; asexual reproduction may compensate for this [1]. Insect visitors to the N. bigelovii- N. parryi complex primarily bees (honey bees, solitary native bees; [2]). Seeds disseminated by disarticulation of pedicel, with wind and rains presumed to aid in the process. Seedling recruitment in N. bigelovii- N. parryi complex considered rare due to seed predation [2].

Threats

Fire suppression leading to fuels accumulation increases vulnerability to fire because of increased fire intensity leading to increased risk of mortality and seed bank destruction [1]. Frequent fire can prevent plants from reaching reproductive maturity. Threatened by residential development, vehicles, altered fire regimes, and horticultural collecting; possibly threatened by non-native plants [6].

Special Considerations:

Because of affinity for clay soils, often associated with other rare plant species [1]. Dice (1988) notes population sizes may have been overstated in some instances; provides an example of a small population with 2000 rosettes he estimated to represent 50 individuals based on counting discrete clusters of rosettes separated by at least 0.5m, but in a preliminary genetic analysis found each cluster was genetically identical at 15 loci.

Literature Sources

[1] USFWS (U.S. Fish and Wildlife Service). 1998. 50 CFR Part 17: Endangered and Threatened Wildlife and Plants; Withdrawal of Proposed Rule to List Nolina interrata (Dehesa beargrass) as Threatened. Federal Register 63(197):54972-54974.

[2] Dice, J.C. 1988. Systematic Studies in the Nolina bigelovii-N parryi (Nolinaceae) Complex. A thesis presented to San Diego State University. 203 pp.

[3] Reiser, C.H. 1994. Rare Plants of San Diego County. Aquafir Press, Imperial Beach, CA. Available online: http://sandiego.sierraclub.org/rareplants/

[4] MSP-MOM. 2014. Management Strategic Plan Master Occurrence Matrix. http://sdmmp.com/reports_and_products/Reports_Products_MainPage.aspx

[5] USFWS (U.S. Fish and Wildlife Service). 1997. 50 CFR Part 17: Endangered and Threatened Species; Review of Plant and Animal Taxa; Proposed Rule. Federal Register 62(182):49397-49411.

[6] CNPS, Rare Plant Program. 2014. Inventory of Rare and Endangered Plants (online edition, v8-02). California Native Plant Society, Sacramento, CA. Website http://www.rareplants.cnps.org [accessed 17 June 2014].