Clark S. Winchell

Species prioritization for monitoring and management in regional multiple species conservation plans

ABSTRACT Successful conservation plans are not solely achieved by acquiring optimally designed reserves. Ongoing monitoring and management of the biodiversity in those reserves is an equally important, but often neglected or poorly executed, part of the conservation process. In this paper we address one of the first and most important steps in designing a monitoring program – deciding what to monitor. We present a strategy for prioritizing species for monitoring and management in multispecies conservation plans. We use existing assessments of threatened status, and the degree and spatial and temporal extent of known threats to link the prioritization of species to the overarching goals and objectives of the conservation plan. We consider both broad and localized spatial scales to capture the regional conservation context and the practicalities of local management and monitoring constraints. Spatial scales that are commensurate with available data are selected. We demonstrate the utility of this strategy through application to a set of 85 plants and animals in an established multispecies conservation plan in San Diego County, California, USA. We use the prioritization to identify the most prominent risk factors and the habitats associated with the most threats to species. The protocol highlighted priorities that had not previously been identified and were not necessarily intuitive without systematic application of the criteria; many high‐priority species have received no monitoring attention to date, and lower‐priority species have. We recommend that in the absence of clear focal species, monitoring threats in highly impacted habitats may be a way to circumvent the need to monitor all the targeted species.

DIETARY OVERLAP OF AN ALIEN AND NATIVE CARNIVORE ON SAN CLEMENTE ISLAND, CALIFORNIA

Abstract Predation by feral cats (Felis catus) is recognized as a major threat to native fauna worldwide, but the competitive effects of cats on native species have not been extensively studied. Cats occur on San Clemente Island, California, in sympatry with endemic island foxes (Urocyon littoralis clementae). We examined diets of cats and island foxes between years, seasons, and habitats to assess the potential for resource competition between the 2 species. Analysis of 602 cat and 958 fox feces revealed a high level of dietary overlap (O = 0.93) and relatively narrow niche breadths for both species (Bstandard Fox = 0.37; Bstandard Cat = 0.49). Despite the overlap in diet, cats and foxes appear to partition prey resources. Cats consume approximately equal proportions of arthropod (47.9%) and vertebrate (44.2%) prey, the latter primarily rodents (29.2%) and lizards (12.9%). In contrast, foxes appear to rely more on arthropods (57.7%), with plants (20.5%) and vertebrates (21.6%) occurring in lower, but roughly equal frequencies. Season appeared to have little effect on diet; however, diet did vary between habitats and years for both species. Diets of cats on San Clemente Island are consistent with those from other studies. We found no evidence of a dietary shift by foxes that were in sympatry with cats.

Research Priorities from Animal Behaviour for Maximising Conservation Progress

Poor communication between academic researchers and wildlife managers limits conservation progress and innovation. As a result, input from overlapping fields, such as animal behaviour, is underused in conservation management despite its demonstrated utility as a conservation tool and countless papers advocating its use. Communication and collaboration across these two disciplines are unlikely to improve without clearly identified management needs and demonstrable impacts of behavioural-based conservation management. To facilitate this process, a team of wildlife managers and animal behaviour researchers conducted a research prioritisation exercise, identifying 50 key questions that have great potential to resolve critical conservation and management problems. The resulting agenda highlights the diversity and extent of advances that both fields could achieve through collaboration.

Fire management, managed relocation, and land conservation options for long-lived obligate seeding plants under global changes in climate, urbanization, and fire regime.

Most species face multiple anthropogenic disruptions. Few studies have quantified the cumulative influence of multiple threats on species of conservation concern, and far fewer have quantified the potential relative value of multiple conservation interventions in light of these threats. We linked spatial distribution and population viability models to explore conservation interventions under projected climate change, urbanization, and changes in fire regime on a long-lived obligate seeding plant species sensitive to high fire frequencies, a dominant plant functional type in many fire-prone ecosystems, including the biodiversity hotspots of Mediterranean-type ecosystems. First, we investigated the relative risk of population decline for plant populations in landscapes with and without land protection under an existing habitat conservation plan. Second, we modeled the effectiveness of relocating both seedlings and seeds from a large patch with predicted declines in habitat area to 2 unoccupied recipient patches with increasing habitat area under 2 projected climate change scenarios. Finally, we modeled 8 fire return intervals (FRIs) approximating the outcomes of different management strategies that effectively control fire frequency. Invariably, long-lived obligate seeding populations remained viable only when FRIs were maintained at or above a minimum level. Land conservation and seedling relocation efforts lessened the impact of climate change and land-use change on obligate seeding populations to differing degrees depending on the climate change scenario, but neither of these efforts was as generally effective as frequent translocation of seeds. While none of the modeled strategies fully compensated for the effects of land-use and climate change, an integrative approach managing multiple threats may diminish population declines for species in complex landscapes. Conservation plans designed to mitigate the impacts of a single threat are likely to fail if additional threats are ignored.

Planning, implementing, and monitoring multiple-species habitat conservation plans.

PREMISE OF THE STUDY Despite numerous recommendations for various aspects of the design and monitoring of habitat conservation plans, there remains a need to synthesize existing guidelines into a comprehensive scheme and apply it to real-world conservation programs. METHODS We review tools for systematic conservation planning and elements for designing and implementing ecological monitoring in an adaptive management context. We apply principles of monitoring design to the San Diego Multiple Species Conservation Program (MSCP) in California, USA--one of the first multispecies habitat conservation plans, located in a landscape where high biodiversity and urban development converge. KEY RESULTS Tools for spatial conservation planning are aimed to conserve biodiversity, often in the context of a limited budget. In practice, these methods may not accommodate legislative mandates, budgetary uncertainties, and the range of implementation mechanisms available across consortia of stakeholders. Once a reserve is implemented, the question becomes whether it is effective at conserving biodiversity, and if not, what actions are required to make it effective. In monitoring plan development, status and threats should be used to prioritize species and communities that require management action to ensure their persistence. Conceptual models documenting the state of knowledge of the system should highlight the main drivers affecting status and trends of species or communities. Monitoring strategies require scientifically justified decisions based on sampling, response, and data design. CONCLUSIONS Because the framework illustrated here tackles multiple species, communities, and threats at the urban-wildland interface, it will have utility for ecosystem managers struggling to design monitoring programs.

Using California Gnatcatcher to Test Underlying Models in Habitat Conservation Plans

Abstract Habitat Conservation Plans are a widely used strategy to balance development and preservation of species of concern and have been used in southern California, USA, to protect the coastal California gnatcatcher (Polioptila californica). Few data exist on gnatcatcher abundance and distribution, and existing data have problems with issues of closure (i.e., sampling occurs in a short enough time period such that abundance or distribution are not changing), detectability, and proper attention to probability-based sampling schemes. Thus, a habitat model has been relied upon in reserve design. California gnatcatchers are the flagship and umbrella species of many plans and we provide the first estimates that incorporate probabilistic sampling and test predictions from the habitat model. Probability of occurrence was 26% (SÊ = 0.06); however, occupancy varied by modeled habitat quality with slopes <40%, warm, and wet sagebrush habitat having higher occupancy probabilities. Interpreting abundance and occupancy probabilities by vegetation type was complicated by error detected in Geographic Information System vegetation metadata files. The slope (1.08, SÊ = 0.66), temperature (0.79, SÊ = 0.70), and precipitation (−2.62, SÊ = 1.21) variables associated with habitat models were stronger influences on occupancy than was patch size (0.48, SÊ =0.66). Previous models weight patch size equal to slope and climate. Our work demonstrates that probabilistic sampling can be carried out on a large scale and the results provide better information for managers to make decisions about their reserves.

Effects of habitat quality and wildfire on occupancy dynamics of Coastal California Gnatcatcher (Polioptila californica californica)

ABSTRACT Habitat Conservation Plans (HCPs) are a mechanism used for conserving land and often have an umbrella species associated with them. We conducted occupancy surveys for an umbrella species, the Coastal California Gnatcatcher (Polioptila californica californica), from 2004 to 2009 in San Diego County, California, focusing on preserve lands associated with HCPs. We investigated the effects of habitat quality classification, elevation, distance to coast, and heat load on gnatcatcher occupancy, extinction, and colonization probabilities. Our work focused on these factors throughout the range of this species in San Diego County where, through conservation agreements, a preserve system has been assembled addressing management considerations at a landscape scale. In addition, a large wildfire in 2003 burned 17,044 ha, roughly 1/3 of preserve lands, thus we were able to investigate the recolonization process associated with this event. We found that occupancy increased with habitat quality and over time, but decreased with elevation. Extinction probability was generally constant (∼0.13), but colonization varied greatly, with probabilities being greater in higher quality habitat and at lower elevations. Gnatcatchers were more likely to colonize burned areas adjacent to high and very high quality habitat, sites that should receive priority conservation actions, particularly at lower elevations. Our work suggests that umbrella species, like the California Gnatcatcher, may reflect not just habitat quality, but may also be useful indicators of recovery after an unexpected event such as fire. Although not perfect, the use of multiple umbrella species in HCPs may lead to effective conservation and management of biodiversity hotspots.

Restoring habitat for coastal California Gnatcatchers (Polioptila californica californica)

ABSTRACT One goal of Habitat Conservation Plans is to protect viable populations of animal species. Management actions included in such plans often focus on vegetation restoration to benefit the target animal species. Yet, such restoration activities are often uninformed by fine-scale animal survey data. Using the California Gnatcatcher (Polioptila californica californica), we demonstrate how survey data can guide restoration toward the goal of improving gnatcatcher viability by identifying habitat conditions most favorable for gnatcatcher occupancy. We found that gnatcatcher presence and colonization probabilities tripled as the coverage of coastal sagebrush (Artemisia californica) increased from 10% to 40%. Coastal sagebrush was more likely to be present at low elevations, and was most closely associated with soil texture of 5%–20% clay, 40%–70% sand, and 20%–40% silt. Higher gnatcatcher extinction probabilities were associated with closed, dense habitat; optimal conditions were between 30% and 40% openness, creating a slightly closed canopy. Open habitat was associated with southern aspects, shallow slopes, and inland areas. An understanding of the soil types and physical parameters of the environment that affect vegetation, especially the amount of coastal sagebrush needed for high gnatcatcher occupancy and colonization rates, will help to define restoration target conditions. Using multiseason, occupancy-based surveys in conjunction with detailed habitat measurements will allow ornithologists and land managers to design powerful restoration prescriptions, even within narrowly defined ecosystems.

Prioritizing conserved areas threatened by wildfire and fragmentation for monitoring and management

In many parts of the world, the combined effects of habitat fragmentation and altered disturbance regimes pose a significant threat to biodiversity. This is particularly true in Mediterranean-type ecosystems (MTEs), which tend to be fire-prone, species rich, and heavily impacted by human land use. Given the spatial complexity of overlapping threats and species’ vulnerability along with limited conservation budgets, methods are needed for prioritizing areas for monitoring and management in these regions. We developed a multi-criteria Pareto ranking methodology for prioritizing spatial units for conservation and applied it to fire threat, habitat fragmentation threat, species richness, and genetic biodiversity criteria in San Diego County, California, USA. We summarized the criteria and Pareto ranking results (from west to east) within the maritime, coastal, transitional, inland climate zones within San Diego County. Fire threat increased from the maritime zone eastward to the transitional zone, then decreased in the mountainous inland climate zone. Number of fires and fire return interval departure were strongly negatively correlated. Fragmentation threats, particularly road density and development density, were highest in the maritime climate zone, declined towards the east, and were positively correlated. Species richness criteria showed distributions among climate zones similar to those of the fire threat variables. When using species richness and fire threat criteria, most lower-ranked (higher conservation priority) units occurred in the coastal and transitional zones. When considering genetic biodiversity, lower-ranked units occurred more often in the mountainous inland zone. With Pareto ranking, there is no need to select criteria weights as part of the decision-making process. However, negative correlations and larger numbers of criteria can result in more units assigned to the same rank. Pareto ranking is broadly applicable and can be used as a standalone decision analysis method or in conjunction with other methods.

A comparison of point-count and area-search surveys for monitoring site occupancy of the Coastal California Gnatcatcher (Polioptila californica californica)

ABSTRACT Improving the efficiency of monitoring protocols prescribed by conservation plans can release typically limited funding for other management and conservation activities. We present an approach for optimizing protocols that considers the precision of parameter estimates, costs of implementation, and broader monitoring-program goals. In a case study of the Coastal California Gnatcatcher (Polioptila californica californica), we compared the efficiency of point-count surveys (with and without playbacks of vocalizations) and area-search surveys (with playbacks) for estimating site occupancy. Conducting an area-search survey of a 2.25 ha plot required an average of 19 min longer than conducting an 18-min point-count survey (15 min of silent observation followed by 3 min of playbacks) at the same location. However, the estimated detection probability (p) during a single visit was lower for point counts (0.41 ± 0.05) than for area searches (0.69 ± 0.05), while both methods generated similar occupancy (Ψ) estimates (0.34 ± 0.06). To obtain the specified level of precision for estimates of occupancy (i.e. with 10% coefficient of variation), the total survey effort (travel time + survey time) was projected to be 35% lower for area searches than for point counts because of differences in detection probability and, thus, in the required numbers of sites and visits per site. For point counts, detection probability increased from 0.35 ± 0.02 to 0.46 ± 0.03 visit−1 after playbacks were broadcast at the end of the count. Free use of playbacks is one of the factors that contributed to the higher detection probability of the area-search method, but playbacks may introduce a slight positive bias into occupancy estimates. Because there are tradeoffs in switching to area-search methods, the decision to switch protocols demands full consideration of monitoring-program goals and the costs and benefits of each survey approach.