Managing The National Wildlife Refuge System With Climate Change: The Interaction Of Policy, Perceptions, And Ecological Knowledge

Thesis (Ph.D.) University of Alaska Fairbanks, 2009The National Wildlife Refuge System (NWRS) is committed to conserving fish, wildlife, and plants for current and future generations of Americans. Given a rapidly changing climate, managers may employ various adaptation strategies to meet legislated mandates. I explore how ecological context, policy, perceptions and available ecological knowledge inform adaptation strategies. In Chapter 2, I develop an ecosystem vulnerability framework to better understand how climate change risk and ecosystem resilience interact to impact the NWRS. With GIS, I rank refuges based on historic temperature change, historic precipitation change, and sea-level rise risk. To index resilience, I rank refuges based on refuge size, landscape road density, and elevation range. Using this GIS analysis and the ecosystem vulnerability framework, I categorize the 527 refuges into four groups (refugia, ecosystem maintenance, facilitate transitions, and experiments in natural adaptation) that provide a necessary context for national, strategic adaptation planning. In Chapter 3, I survey 32% of NWRS biologists and managers to understand how policy and their perceptions of climate change influence adaptation choice. Currently, managers and biologists independently decide if climate change is natural or anthropogenic for wildlife management, and this conceptualization becomes important for deciding whether reactionary or anticipatory adaptation approaches are more appropriate. Although respondents considered practicability, they prefer historic condition. Respondents also prefer ecosystems and species adapt naturally. In a rapidly changing climate, natural adaptation may not be feasible without large-scale extinction. Nonetheless, many biologists and managers are uncomfortable with the alternative of manipulating ecosystems and species assemblages toward future conditions. Finally, understanding climate change impacts requires the analysis of complex ecological relationships over time and this complexity creates another barrier for implementing a national adaptation strategy. In Chapter 4, using a data-mining approach on data from scaled-down GCMs and an atypical monitoring approach, I build bioclimatic envelope models to show how the distributions of two passerines will potentially shift in response to climate change over the next 100 years on Kenai National Wildlife Refuge. In order to effectively manage species within the context of strategic adaptation planning, the NWRS must design future biological monitoring approaches with spatial modeling in mind

Satellite-Based Assessment of Grassland Conversion and Related Fire Disturbance in the Kenai Peninsula, Alaska

Spruce beetle-induced (Dendroctonus rufipennis (Kirby)) mortality on the Kenai Peninsula has been hypothesized by local ecologists to result in the conversion of forest to grassland and subsequent increased fire danger. This hypothesis stands in contrast to empirical studies in the continental US which suggested that beetle mortality has only a negligible effect on fire danger. In response, we conducted a study using Landsat data and modeling techniques to map land cover change in the Kenai Peninsula and to integrate change maps with other geospatial data to predictively map fire danger for the same region. We collected Landsat imagery to map land cover change at roughly five-year intervals following a severe, mid-1990s beetle infestation to the present. Land cover classification was performed at each time step and used to quantify grassland encroachment patterns over time. The maps of land cover change along with digital elevation models (DEMs), temperature, and historical fire data were used to map and assess wildfire danger across the study area. Results indicate the highest wildfire danger tended to occur in herbaceous and black spruce land cover types, suggesting that the relationship between spruce beetle damage and wildfire danger in costal Alaskan forested ecosystems differs from the relationship between the two in the forests of the coterminous United States. These change detection analyses and fire danger predictions provide the Kenai National Wildlife Refuge (KENWR) ecologists and other forest managers a better understanding of the extent and magnitude of grassland conversion and subsequent change in fire danger following the 1990s spruce beetle outbreak

Satellite-Based Assessment of Grassland Conversion and Related Fire Disturbance in the Kenai Peninsula, Alaska

Spruce beetle-induced (Dendroctonus rufipennis (Kirby)) mortality on the Kenai Peninsula has heightened local wildfire risk as canopy loss facilitates the conversion from bare to fire-prone grassland. We collected images from NASA satellite-based Earth observations to visualize land cover succession at roughly five-year intervals following a severe, mid-1990's beetle infestation to the present. We classified these data by vegetation cover type to quantify grassland encroachment patterns over time. Raster band math provided a change detection analysis on the land cover classifications. Results indicate the highest wildfire risk is linked to herbaceous and black spruce land cover types, The resulting land cover change image will give the Kenai National Wildlife Refuge (KENWR) ecologists a better understanding of where forests have converted to grassland since the 1990s. These classifications provided a foundation for us to integrate digital elevation models (DEMs), temperature, and historical fire data into a model using Python for assessing and mapping changes in wildfire risk. Spatial representations of this risk will contribute to a better understanding of ecological trajectories of beetle-affected landscapes, thereby informing management decisions at KENWR

Ecosystem and Wildlife Implications of Brush: Management System Designed to Improve Water Runoff and Percolation

With the settlement of Texas and establishment of ranchers to produce cattle, there was an effort to maximize beef production. This caused serious overgrazing. In addition, there was a reduced incidence of fires across the landscape to clear out brush. These factors led to deterioration of the grazing lands and provided an opportunity for invasive intrusion by brush and other species onto the land and riparian zones. There has been a large-scale conversion from grasslands and savannahs to wildlands over the last 150 years (Scholes and Archer, 1997). The overall impacts are significantly impaired uplands and reduced percolation and surface flow of water from rainfall which caused changes and loss in basic aquatic and terrestrial habitat. The State of Texas adopted a program to study and implement brush management systems across the state to improve the water availability in streams, rivers, reservoirs and aquifers, as well as to improve the rangelands. The feasibility studies have shown great promise for improving ranchland and improving the water situation. However, there is less known about the aquatic and wildlife species response implications of brush management. Certainly, there are opportunities for improving the viability of an ecosystem through brush management strategies and continuing management practices. The purpose of this study was to evaluate the changes in hydrology and biological diversity associated with brush management in two watersheds where significant data was already available. This study focused on assessing the aquatic and terrestrial species implications related to specified brush management strategies over time. This involved an integrated analysis including modeling of the landscape, assessing biological diversity and developing economic implications for the two watersheds (Twin Buttes and Edwards regions). Thus, this study is comprised of three parts: modeling of brush management strategies temporally, assessing biological diversity (aquatic and terrestrial) and estimating economic implications. This represents a complex analysis involving variable units and multiple disciplines. Previous feasibility studies of brush removal have been targeted at maximizing water runoff. This analysis is an extension that is designed to examine the implications of brush management under a more restrictive set of brush removal criteria that were chosen based upon wildlife considerations. To achieve the integration of hydrologic modeling, range ecology, and economic implications, there were three team meetings bringing together all components to review status and set priorities for the remainder of the work. In addition, scientists in the three basic groups of specialization interacted daily along with representatives of the Corps of Engineers to assure that each decision was reflected in other parts of the analyses. The major addition of this analysis to brush management feasibility studies being conducted as part of the Texas brush management plan is the consideration of wildlife and aquatic biota and assessing changes in biological diversity likely to result from alternative brush management scenarios

Breeding and wintering bird occurence in Texas rangelands with special reference to woody plant encroachment

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 67-74).Issued also on microfiche from Lange Micrographics.Within the past 150 years, rangeland vegetation in Texas has undergone a large-scale conversion from grasslands and savannas to shrublands and woodlands. Concurrently, grassland bird species have shown more declining trends than any other avian species group in North America. However, in Texas, many bird species and an endangered species utilize the encroaching woody plants. I studied breeding and wintering species within 2 watersheds on the Edwards Plateau. Breeding birds were surveyed with 498 point counts and wintering birds with 280 line transects across the range of vegetation conditions within the watersheds during 2001 and 2002. Grassland-associated species had a negative association with juniper in both watersheds, but associations with mesquite differed by species. Birds within the shrubland and woodland-associated guilds also had mixed associations with juniper and mesquite that were species specific. The bird assemblages, encroaching woody species, and vegetation characteristics of the 2 watersheds were different. Therefore, management recommendations need to be addressed at the watershed level

Using climate envelope models to identify potential ecological trajectories on the Kenai Peninsula, Alaska.

Managers need information about the vulnerability of historical plant communities, and their potential future conditions, to respond appropriately to landscape change driven by global climate change. We model the climate envelopes of plant communities on the Kenai Peninsula in Southcentral Alaska and forecast to 2020, 2050, and 2080. We assess 6 model outputs representing downscaled climate data from 3 global climate model outputs and 2 representative concentration pathways. We use two lines of evidence, model convergence and empirically measured rates of change, to identify the following plausible ecological trajectories for the peninsula: (1.) alpine tundra and sub-alpine shrub decrease, (2.) perennial snow and ice decrease, (3.) forests remain on the Kenai Lowlands, (4.) the contiguous white-Lutz-Sitka spruce complex declines, and (5.) mixed conifer afforestation occurs along the Gulf of Alaska coast. We suggest that converging models in the context of other lines of evidence is a viable approach to increase certainty for adaptation planning. Extremely dynamic areas with multiple outcomes (i.e., disagreement) among models represent ecological risk, but may also represent opportunities for facilitated adaptation and other managerial approaches to help tip the balance one way or another. By reducing uncertainty, this eclectic approach can be used to inform expectations about the future

Arthropod and oligochaete assemblages from grasslands of the southern Kenai Peninsula, Alaska

By the end of this century, the potential climate-biome of the southern Kenai Peninsula is forecasted to change from transitional boreal forest to prairie and grasslands, a scenario that may already be playing out in the Caribou Hills region. Here, spruce (Picea × lutzii Little [glauca × sitchensis]) forests were heavily thinned by an outbreak of the spruce bark beetle (Dendroctonus rufipennis (Kirby, 1837)) and replaced by the native but invasive grass species, Calamagrostis canadensis (Michx.) P. Beauv. As part of a project designed to delimit and characterize potentially expanding grasslands in this region, we sought to characterize the arthropod and earthworm communities of these grasslands. We also used this sampling effort as a trial of applying high-throughput sequencing metabarcoding methods to a real-world inventory of terrestrial arthropods. We documented 131 occurrences of 67 native arthropod species at ten sites, characterizing the arthropod fauna of these grasslands as being dominated by Hemiptera (60% of total reads) and Diptera (38% of total reads). We found a single exotic earthworm species, Dendrobaena octaedra (Savigny, 1826), at 30% of sites and one unidentified enchytraeid at a single site. The utility of high-throughput sequencing metabarcoding as a tool for bioassessment of terrestrial arthropod assemblages was confirmed

A Multi-Scale Blueprint for Building the Decision Context to Implement Climate Change Adaptation on National Wildlife Refuges in the United States

Climate change and ecological transformation are causing natural resource management to be applied to nonstationary systems. Managers can respond to dynamic ecosystems by resisting, accepting, or directing ecological change. Management response is constrained by a decision context, defined as an interconnected social system of values, rules, and knowledge that affects how problems can be addressed. We provide a multi-scale blueprint for creating a decision context that increases capacity for implementing climate adaptation, including novel approaches in the National Wildlife Refuge System, a continental conservation network administered by the U.S. Fish and Wildlife Service. We use the Tetlin National Wildlife Refuge in Alaska as case study to illustrate blueprint concepts and to provide “proof-of-concept” for application. The blueprint builds on ideas and practices from scenario planning, adaptive management, and adaptive pathway planning, which are approaches that promote action in the face of uncertainty. Management considerations focus on stewarding biodiversity in a changing climate by addressing what futures are possible, what interventions can be used to shape future conditions, and how to coordinate a regional conservation strategy. The blueprint focus on decision context promotes a longer-term social process of engagement that is complementary to, but larger than, any one decision process