Executive Summary

1.  Overview

Introduction

NATURAL AREAS PROGRAM

NAP Background and  Goals

Objectives

Definitions

2. Management Approach

Goals

Values

Strategies

3. Setting

Biology

Vegetation

Wildlife

Landuse History

4. IPM

5. General Recommendation

Vegetation

Birds

Mammals

Soils, Erosion, and Public Use

6.Site Specific Recommendations

7. Monitoring

Issue GR-1: Areas of invasive non-native vegetation (e.g., wild oat grasslands, exotic forests, and French broom) occur within and adjacent to the Critical Areas. These species are responsible for historic loss of biodiversity and could spread through the Critical Areas. Removal of invasive vegetation results in opportunities for revegetation. Recently restored areas may also be subject to higher rates of invasion than established habitats and, therefore, follow-up maintenance of weed control and restoration areas is critical.          

Recommendation GR-la: The invasive plant in- holdings shall be reduced or eradicated.

Recommendation GR-lb- Where native plant seed sources do not exist or have diminished, restoration with appropriate native species shall occur. Native species shall be planted to simulate the diversity, cover, and density of adjacent habitat or reference plots in similar habitats at other parks (Appendix B).

Recommendation GR-1c: In areas where it may not be feasible to reduce or eradicate large infestations of non- native vegetation immediately, containment actions along the interface between the native and non-native habitats shall occur and any spread of invasive species controlled.

Recommendation GR-1d: Critical Areas that include large portions of non-native grasslands often contain smaller areas of important native-dominated vegetation (e.g., purple needlegrass prairie within a wild oat grassland). These areas shall be weeded on a routine basis to preserve the integrity of the native plant series and reduce the infestation of non-native species. Additionally, removal of small areas of non-native species along the edges of the native habitats would allow native species to increase gradually. Recommendation GR-le: Within the exotic forests, recruitment shall be limited by routine removal of saplings and seedlings. As the stands age, small groups of trees could be removed within the forest and replanted with the appropriate native species.

Recommendation GR-1f: Critical Areas, restoration areas, and other sensitive habitats shall be routinely monitored for invasion of undesired plant species (Section 7).

Issue GR-2: The Significant Natural Resource Areas contain several vegetation series and many individual species of limited distribution and significant local importance. For example, red fescue prairie is found within five Natural Areas (McLaren, Twin Peaks, O'Shaughnessy Hollow, Duncan-Castro, and Rock Outcrop) and amounts to a total of only 1.37 acres. There are many other vegetation series of limited distribution within the system (Table 3-3). Twenty- four species of special-status plants occur in limited numbers through the Natural Areas (Table 3-4). For example, San Francisco spineflower (Chorizanthe cuspidata var. cuspidata) was recently discovered during restoration activities near Impound Lake (Section 6. 1) and the only population of yellow-eyed grass known in San Francisco can be found in Glen Canyon Park (Section 6.3).

Recommendation GR-2a: These populations, both individual plants and groups of plants that make up a series, shall be closely monitored to ensure their continued survival (Section 7). This would be relatively simple to accomplish because they occur only in selected locations. If the monitoring data show that populations are declining or unstable, efforts shall be made by the San Francisco Recreation and Park Department (SFRPD) to ensure the survival of these species. These efforts include increasing the population size, planting, and changing the management regime (see Recommendation GR-2c).

Recommendation GR-2b: Areas supporting these species and series shall be given priority in work to eradicate invasive species (see Recommendation GR-1d). Recommendation GR-2c: These species shall be given priority for use in revegetation and reintroduction activities throughout the Significant Natural Resource Areas System. Augmenting existing populations of these plants and establishing new ones in multiple Natural Areas would help to ensure their continued survival. This could include collecting seed from local populations and then either broadcasting it or propagating it and planting individuals to increase local populations.

Recommendation GR-2d- Plants shall be installed at densities and in composition that correspond to similar existing habitats in other locations and are appropriate for that location (Appendix B). Planting plans shall take into account species that may have historically occurred within a Natural Area or within San Francisco and make reintroductions as appropriate (Appendix E).

Recommendation GR-2e: Efforts shall be made to protect the areas containing these species from human- generated disturbances.

Issue GR-3: Non-native grasslands can be found in most Natural Areas. These species typically out- compete native species. The interruption of natural process such as fire and native herbivore grazing has resulted in conditions favorable to the non-native species. This means that native grasslands within many Natural Areas are at risk of being over-run by invasive species because conditions may not be optimal for supporting native species.

Recommendation GR-3a: SFRPD shall carefully monitor native grasslands and control invasive species (see Recommendation GR-la through f).

Recommendation GR-3b: Management of larger expanses of grasslands shall explore non-traditional methods of grass control. Areas could be burnt at the appropriate time of year to help native species germinate and to control exotics. Similarly, controlled grazing could reduce the populations of undesirable species and improve conditions for native grasses. In both of these methods, the management action is applied before the native grasses sprout or after they have finished setting seed.