CNAS

Habitat Conservation Plans: Moving Across Boundaries

The Jane Block Distinguished Seminar Series in Conservation Biology

November 9-10, 2009

Beckman Center, San Diego Zoo's Wild Animal Park

Abstracts

Corridors, fragmentation, and species conservation across boundaries

Doug Bolger, Environmental Studies Program, Dartmouth College

The last ten years has seen a proliferation of scientific literature on habitat fragmentation, corridors and connectivity. Here I selectively review the literature for recent results particularly relevant to HCP connectivity issues. In particular, I highlight results relevant to assessing the population -level effectiveness of corridors and other connectivity approaches. Where possible I illustrate these issues with examples from studies conducted in southern California.

Connectivity and barriers for wildlife in southern California: from lizards to mountain lions

Seth P. D. Riley, National Park Service, Santa Monica Mountains National Recreation Area; Ecology & Evolutionary Biology, UC Los Angeles

Urbanization and the resulting habitat fragmentation present many challenges for natural populations, both because of the direct loss of habitat and through the loss of connections between remaining areas of habitat. At Santa Monica Mountains National Recreation Area, a national park next to Los Angeles, urbanization and its effects are the primary factors affecting wildlife communities in the park. Since 1996, we have been studying the effects of urbanization on a range of wildlife taxa including mammalian carnivores, reptiles, and amphibians. Because of their large spatial requirements, carnivores can be particularly affected by large-scale landscape changes. We have seen that while bobcats, coyotes, and mountain lions sometimes cross barriers such as freeways and roads, these barriers significantly restrict movement, directly cause mortality, and may even have less obvious effects such as altering social interactions and reducing gene flow. We have seen that smaller and less mobile species such as lizards, and even a bird, also have reduced gene flow in a fragmented landscape, even if they are still relatively abundant and widespread in the area. We have been working with Caltrans to monitor road effects on wildlife and to attempt to reduce mortality and improve connectivity across major barriers such as freeways. Connectivity is a significant challenge for wildlife in urban landscapes such as those in southern California, but we are learning more about the effects of reduced connectivity and hopefully how to mitigate them.

Added challenges of relocating animals in a fragmented landscape

Debra Shier, Applied Animal Ecology, San Diego Zoo’s Institute for Conservation Research

James Sheppard, Applied Animal Ecology, San Diego Zoo’s Institute for Conservation Research

Relocation programs (captive-breeding reintroduction, translocation and supplementation) are used to introduce species to parts of their historic range. Though they are increasingly popular conservation tools, achieving a successful reintroduction can be challenging. To make these programs even more difficult, habitat is being continually fragmented into smaller units by development. Developmental boundaries create additional biological, regulatory and political challenges for relocations. In this talk, we explore the added complexity of relocating animals within and across boundaries. We illustrate the issues that arise with case studies from species of varying size, home range size and roles in the ecosystem (e.g. the California Condor to Stephens’ kangaroo rat).

Gene flow across boundaries

Oliver Ryder, San Diego Zoo’s Institute for Conservation Research

Connectivity between populations in fragmented landscapes is deemed to be crucial for survival of small populations. Monitoring for population presence and estimation of census size generally fail to allow estimations of animal movements that are prerequisites for gene flow. Marking and following individuals is often too labor intensive and may yield relatively little information. Genetic studies have been used to evaluate migration, dispersal, and to provide metrics assessing aspects of connectivity. As the issue of connectivity and gene flow as processes impacting the likelihood of population persistence becomes a more focused issue in HCP management, new technologies – including genetic analyses – are emerging that offer the potential to significantly increase knowledge of gene flow among metapopulation segments and shine a light on the significance of rare events, including long-distance dispersal and hybridization. For assessment of many issues in population monitoring and management, more systematic and comprehensive efforts to collect and curate biomaterials samples will increase the effectiveness of ongoing management efforts.

Disease and the paradigm of natural area boundaries

Tom Scott, UC Berkeley & UC Riverside

Our concepts of California wildland have always lagged behind the condition of the landscapes we manage, driven by a conceptual separation of natural and human-dominated systems. The utility of this dichotomy has frayed as preserve managers discover new and evolving trans-boundary processes, but conservation biologists have clung to successively more complicated models of naturalness (e.g., island biogeography, fragmentation). Wildland diseases provide a tipping point, where the burden of a human-natural division can be dropped for more pragmatic models of gradients and processes decoupled from need to define what is natural. Diseases have the power to transcend the human-natural dichotomy because they provide irrefutable evidence of connection. Perhaps more important, they identify the new ecosystems and processes we have created that are neither natural nor human dominated, which do not fit into any model of edge.

Invasions across Boundaries - Sahara Mustard in the Desert Southwest: Origins, Patterns and Impacts

Cameron Barrows, Center for Conservation Biology, UC Riverside

Here I present a case study using Sahara mustard, Brassica tournefortii, as an example of the cross-boundary nature of plant invasions in the North America’s desert southwest. First recorded in 1927 from the Coachella Valley, Sahara mustard likely inadvertently accompanied the first date palms imported there from north Africa to begin what quickly became the date palm growing center of the western hemisphere. As date palms were transported to new areas, Sahara mustard soon appeared there as well. From those centers of introduction the mustard seeds were transported downwind by strong winds into wildland habitats, especially in and around desert sand dunes. Secondary invasions were likely facilitated by mustard seeds attached to off-road vehicle equipment. Currently the invasion of Sahara mustard spans the Colorado division of the Sonoran Desert as well as areas within the southern Mojave Desert – all regions of mild winters and predominantly winter rains. Its current distribution encompasses private agriculture lands as well as wildlands owned and managed by BLM, State Parks, CDFG, and FWS Refuges. Not all exotic introductions are invasive and reduce natural biodiversity; Sahara mustard does both. Keyed by early winter rains, the mustard out paces the growth of native annuals which germinate and grow in late winter and early spring. In particularly wet years the mustard forms a homogeneous closed-canopy, blocking access to sun and pollinators for the now understory of native plants. The result is reduced native seed set, and the dominance of mustard in the seed bank. The increasing homogeneity of Sahara mustard in the seed bank has secondary impact on competition between seed predators. As of yet there are no “magic bullets” for controlling Sahara mustard across the broad regions and jurisdictions where it has invaded, although the earlier than natives germination onset provides a window to focus management efforts.

Air pollution, nitrogen deposition, and the invasive species connection

Edie Allen, Botany & Plant Sciences and the Center for Conservation Biology, UC Riverside

Air pollution is a landscape-scale conservation issue that crosses ecological and jurisdictional boundaries. Anthropogenic nitrogen deposition has been occurring in southern California for the past half-century, with highest levels downwind of urban areas. During the same time period there has been extensive vegetation-type conversion of coastal sage scrub and desert scrub to exotic annual grassland, coupled with increased fire frequency and loss of native diversity. Levels of N deposition higher than 25 kg N ha-1 yr-1 occur in Riversidean sage scrub (RSS) and some areas of Diegan sage scrub, and 16 kg ha-1 yr-1 in desert scrub in the Coachella Valley. Most of the N is dry deposition that originates as emissions from fossil fuel combustion, with lesser amounts from agricultural sources. To determine the effects of N deposition on vegetation, we measured plant and soil responses along N deposition gradients, fertilized vegetation at different N levels, and calculated biomass production output from the DayCent biogeochemical model. The gradient survey in RSS showed that exotic grass increased and native plant species richness declined by almost 50% above a threshold of 10 kg N ha-1 yr-1. Nitrogen fertilization of RSS increased exotic grass biomass above 1 T/ha of fine fuel in most years, the threshold fuel amount for fire. Unfertilized plots had this much fine fuel only in wet years. Fertilization studies plus biomass output from the DayCent model in creosote bush scrub showed a significant increase in exotic species biomass and an increased fire risk from exotic grasses with 1 T/ha production during years with moderate to high precipitation at 3 to 8 kg N ha-1 yr-1. Many areas of coastal sage scrub and desert scrub already experience N deposition above these thresholds, suggesting that they will be subject to vegetation type conversion and loss of native diversity due to N deposition. Conservation goals for sensitive habitats will need to include reductions in air pollution to control N emissions.

Habitat fragmentation and altered fire regime create trade-offs for an obligate seeding shrub

Helen Regan, Department of Biology and the Center for Conservation Biology, UC Riverside

Habitat loss is widely considered the greatest threat to biodiversity. However, habitat loss brings with it myriad other threats that exacerbate impacts to biodiversity. For instance, altered fire regime is associated with habitat loss and fragmentation with unknown consequences to biodiversity. Plant functional groups that rely on fire to complete their life cycle may be adversely affected by disruptions to the natural fire regime, particularly when coupled with population declines due to habitat loss. We used a spatially-explicit stochastic population model linked with fire hazard functions to investigate the cumulative effects of habitat loss, fragmentation and altered fire regime on the expected minimum abundance of a long-lived obligate seeding shrub, Ceanothus greggii var. perplexans. This species is endemic to the California floristic province, a biodiversity hotspot, and is representative of a functional group of plants found in many fire-prone ecosystems. We tested the impact of a range of different fire frequencies under three different combinations of fuel accumulation and weather—fuel accumulation, weather and a combination of these. The best average fire return interval for population abundance was consistently in the 30 to 50 year range. However, observed average fire return intervals in highly fragmented areas can be around 20 years or less and model results show this to be detrimental to C. greggii populations. Results also show that if fires are uncorrelated across habitat fragments then the impact of altered fire regime on populations is worse than the impact of habitat fragmentation because of spatial and temporal decoupling of fire events across the landscape. However, the negative impacts of altered fire regime are outweighed by habitat loss as fragmentation increases. Our results show that large unplanned fires, operating under an altered fire regime, are ultimately detrimental to perennial obligate seeding shrubs in fragmented landscapes.

Plant restoration: transboundary issues

Bryan Endress, San Diego Zoo’s Institute for Conservation Research

Climate change and rare species shifts

John Rotenberry, Department of Biology and the Center for Conservation Biology, UC Riverside

Lori Hargrove, Department of Biology, UC Riverside

Kristine L. Preston, Center for Conservation Biology, UC Riverside; Nature Reserve of Orange County

The distribution of many species is constrained by climate; thus, as climate changes we may expect species distributions to change as well. Here we examine both observed and predicted changes in avian species distributions in parts of southern California in relation to current and expected trends in warming temperatures. In 2005-2007 we resurvyed bird communities at 15 sites along a 2200-m elevational gradient in the Santa Rosa – San Jacinto Mountains (the Deep Canyon Transect) that were originally surveyed in 1979-1981. During that period, lower elevations evidenced a significant increase in average annual high temperatures, whereas higher elevations showed a significant increase in average annual lows. Eighteen of 28 bird species shifted upslope (5 significantly), most of which were desert species. The average elevational shift for all 28 species was +116m. We also used ecological niche modeling to predict the future distribution of California Gnatcatcher (Polioptila californica) in southern California under warmer and drier conditions. Unlike most climate modeling efforts, we included the impacts of climate change on gnatcatcher habitat as well. Incorporating these “indirect” effects of climate on distribution leads to considerably more dire predictions about remaining suitable habitat: with even modest changes in temperature and rainfall suitable gnatcatcher habitat may potentially disappear throughout much of its current range. The important feature of both these analyses is that current species distributions around which habitat conservation plans are based may not reflect future distributions.

Summary of issues in Baja California

Ricardo Rodríguez-Estrella, CIBNOR La Paz

Status of Habitat Conservation Planning in San Diego County

Keith Greer, Senior Regional Environmental Planner, San Diego Association of Governments

San Diego County is approaching the two decades mark in the planning, design, approval and implementation of regional conservation plans for endangered species and their habitats. Habitat Conservation Plans (HCPs) have become a common, albeit still controversial, method for conserving endangered species at the regional level while balancing the social and economic needs of a region. Currently four multi-species, multi habitat conservation efforts are underway in San Diego County. Each one is in a various phase of planning, approval and implementation. Several common themes have emerged that transcends all of these planning efforts - long-term funding for implementation, understanding the cost and protocols for adaptive management and biological monitoring, catastrophic events, and maintaining connectivity to surrounding regions (e.g., Baja California Norte). This presentation will describe the current status and challenges faced by the regional conservation efforts in San Diego County.

Update on the Western Riverside County Multiple Species Habitat Conservation Plan

Charles Landry, WRC Regional Conservation Authority

The Western Riverside County Multiple Species Habitat Plan (MSHCP) was developed as a part of the Riverside County Integrated Project (RCIP), a three-part integrated project of transportation, land use and habitat conservation. The MSHCP forms the linchpin of RCIP and is now in its sixth year of implementation and acquisition. The Plan was driven by recognition that infrastructure and land use were driven by environmental issues, especially endangered and threatened species rules. The Plan is one of the largest in both size and number of covered species in the country. At the end of the 25 year acquisition period, a reserve of 500,000 acres will be established in western Riverside County. The reserve will consist of public lands already identified as having reserve value and the additional reserve lands that will be acquired. Significant progress toward reserve assembly has been made. Over 41,000 acres, of the required 153,000 acres of additional reserve lands needed to complete the Plan, have already been acquired. The current economic downturn has also provided significant challenges and opportunities in land acquisition for the Regional Conservation Authority. Riverside County and the 16 western Riverside County cities are fully committed to the maturing program as evidenced by the nearly $400 million expended to date in local, state and federal funds.

Coachella Valley MSHCP/NCCP: An Ecosystem Processes Approach to Conserving Communities and Species Across a Desert Landscape

Katie Barrows, Coachella Valley Association of Governments

The Coachella Valley MSHCP/NCCP is a large regional conservation plan covering approximately 1.1 million acres in the California desert from Palm Springs to the Salton Sea in eastern Riverside County. In one of the fastest growing areas in the state, the CVMSHCP will conserve approximately 230,000 acres to add to an existing landscape of nearly 500,000 acres of local, state, and federal conservation lands. The CVMSHCP integrates conservation of habitat for 27 species with protection of ecological processes, including those necessary to maintain the valley’s sand dune ecosystem, desert dry wash woodlands and other desert natural communities. The conservation goals are accomplished by an aggressive land acquisition program, land use decisions by local jurisdictions to maintain designated conservation areas, and a science-based monitoring and adaptive management program that provides seamless information to both land managers and for land acquisition priorities. The identification and prioritization of core reserves was based on whether the ecosystem processes that serve the natural communities and species conserved within those areas were intact. By focusing on sites with intact ecosystem processes, communities and species therein should experience a higher degree of sustainability and resilience to a dynamic desert environment, including buffering the impacts of climate change. The challenges of securing habitat for species, as well as maintaining connectivity and ecological processes in an urbanizing environment will be discussed.

The Nature Reserve of Orange County: A Unique Model for Implementing Orange County’s Central - Coastal Natural Community Conservation Plan/Habitat Conservation Plan

Kris Preston, The Nature Reserve of Orange County; Center for Conservation Biology, UC Riverside

Trish Smith, The Nature Conservancy; The Nature Reserve of Orange County

Lyn McAfee, The Nature Reserve of Orange County

Orange County’s Central-Coastal Natural Community Conservation Plan/Habitat Conservation Plan (NCCP/HCP) was established in 1996 to conserve three Target Species (orange-throated whiptail, California Gnatcatcher, Coastal Cactus Wren) on ~37,000 acres extending from the coast to the Santa Ana Mountains. An additional 41 species are covered or conditionally covered by the NCCP/HCP. The Nature Reserve of Orange County (NROC) is a non-profit 501(c)(3) organization responsible for implementing the NCCP/HCP, which is composed of multiple land owners and several land managers. The NROC Board of Directors consists of representatives from participating land owners, the wildlife agencies, and various public interests. The Land Manager Council and Technical Advisory Committee were established to provide recommendations for monitoring and management activities in the Reserve. Initially, the Nature Conservancy provided technical expertise to monitor and manage lands and species within the NCCP/HCP and initiated a number of important projects, including long-term and large-scale invasive plant species program and development of a comprehensive restoration and enhancement plan. Over the last several years, NROC has grown to include a small staff to implement monitoring and management projects and coordinate activities of other land managers including Orange County Parks, Irvine Ranch Conservancy, the Transportation Corridor Authority, California State Parks, California Department of Fish and Game, and the US Fish and Wildlife Service. This organizational structure provides considerable flexibility, allowing NROC to collaborate with a variety of partners for the benefit of projects within the Reserve, while strengthening region-wide conservation opportunities. Examples of recent projects transcending NROC’s boundaries include a Cactus Wren survey and monitoring collaboration, a project to develop efficient vegetation monitoring protocols for southern California NCCPs, and collaboration with the USFWS to evaluate California Gnatcatcher monitoring protocols. Other NROC projects with region-wide relevance include partnering in a USDA Integrated Grant to develop a framework for large-scale and cost effective habitat restoration, development of a Tecate Cypress Management Plan, and participating in a project that is being initiated to reintroduce endangered Quino Checkerspot into historic habitats in Orange County.

Habitat Conservation Plans for Florida Scrub-Jays and Xeric Oak Scrub: Biological and Political Impediments to Success

Reed Bowman, Archbold Biological Station

Although several county-wide HCPs for Florida Scrub-Jays (FSJ) or multi-species HCPs for endemic scrub species have been attempted, none have been successfully implemented. Because the FSJ is well-studied, few HCPs have lacked data and species-specific spatially-explicit PVAs have been used to develop reserve designs with robust models of extinction risks. Fewer data are available for other species included in multi-species HCPs; however, the FSJ appears to be an excellent umbrella species. Like scrub, FSJ populations are highly fragmented. Populations are structured into metapopulations (in which demographic rescue might occur) and larger units in which some genetic homogeneity occurs. Rarely do these coincide with the political boundaries of HCPs and, to date, no cooperative HCPs have been attempted. The FSJ has persisted in some urbanized areas of the state and the USFWS has developed a policy to streamline ITPs for suburban lots; however, this process has reduced the perceived benefits of HCPs thus reducing a major incentive for some constituencies. I will discuss these various impediments to HCPs for Florida Scrub-Jays and scrub and the direction of on-going HCPs to address them.

Panel 1: Monitoring for connectivity and process functionality

Oliver Ryder, San Diego Zoo’s Institute for Conservation Research

Amy Vandergast, USGS Western Ecological Research Center

Panel 2: Habitat connectivity and management across boundaries

Cameron Barrows, UC Riverside

Reed Bowman, Archbold Research Station

Panel 3: Integrating ecological processes across jurisdictional boundaries

Brenda Johnson, California Department of Fish & Game

Pete Stine, USDA Forest Service