The research agenda

The following research program can resolve unanswered questions that bear on the conservation of target species that inhabit coastal sage scrub and the biodiversity associated with that community. The SRP recommends six interactive research tasks.

  1. Biogeography and inventory of CSS. The basic extent and distribution of CSS vegetation and its constituent species should be adequately mapped for the region and each subregion. This information will be required to support any subregional plan. The comprehensive literature review of CSS initiated by the SRP should be expanded and kept current.

    For the southern California region, maps of the planning region should be provided at a scale of 1:100,000, with minimum mapping units of 100 ha (250 acres) and a minimum resolution of 100 m (330 feet). Ideally these maps would be GIS-based. Data layers should include vegetation, urban and agricultural land use, land ownership, topography, climate, distribution of target species, and available information on species of concern.

    For each subregion, GIS-based maps (or accurate manually drawn maps based on similar data) should be provided at a scale of 1:24,000 with minimum mapping units of 10 ha (25 acres) and minimum resolution of 30 m (100 feet). Data layers should include those required for regional planning as well as specific conditions relevant to the subregion, with great emphasis on ground-truthing and verification of data.

  2. Trends in biodiversity. It is the intent of the NCCP to preserve a substantial representation of the biodiversity associated with CSS. Better information on the effect of reserve size and adjoining land uses on biodiversity would help planning decisions. Monitoring of select taxa is necessary to assess the ongoing success of CSS community conservation efforts. Indicator taxa (such as CSS dependent birds, small mammals, and butterflies) should be employed due to time and funding constraints. The relationships between species richness/composition and habitat patch area and the effects of isolation should be investigated in sampling programs. These sampling programs will entail surveys for species richness and composition within a carefully selected series of CSS patches in each subregion.

  3. Dispersal characteristics and landscape corridor use. More information about dispersal limitations of CSS species would help planning for adequate linkages between reserves and reveal trade-offs between increasing reserve size and improving corridors. Dispersal information adequate to allow tests of sensitivity of metapopulation models to connectivity are required. Data from several locations within the planning region during both breeding and non-breeding seasons should be gathered on target species, mountain lions, coyotes, and representative small mammals and invertebrates.

  4. Demography and population viability analysis. One test of the potential effectiveness of reserve systems is population viability analysis. Time-series data on the two target species of birds should be gathered in at least half the subregions and from representative physical circumstances that span those found across the regional distributions of the species. Data should include territory size, time budgets, reproductive success, survivorship, emigration and immigration, with separate data obtained both for males and females where possible. Population viability analyses should be carried out for sample populations and metapopulations, and should consider connectivity and environmental effects.

  5. Surveys and autecological studies of sensitive animals and plants. Basic information on the location, abundance, distribution, and natural history of vertebrate and invertebrate candidate species for federal protection and CSS-associated plant species of special concern should be gathered from select sites throughout the planning region. Each subregional planning exercise should contribute to this regional effort.

  6. Genetic Studies. The maintenance of genetic variation is critical to the long-term viability of species inhabiting CSS and will be an important aspect of monitoring populations under a NCCP. Declining genetic variation will be one symptom of inadequate linkages between reserves and can signal a need for changes in reserve management. Baseline data for comparison with future conditions should be gathered at the earliest possible opportunity. Target species and several invertebrates should be sampled from several locations in each subregion. Most genetic data can be obtained with non-destructive sampling techniques in conjunction with other studies that require handling of individual animals.

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