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Context Conservation scientists recommend maintaining and restoring ecological connectivity to sustain biodiversity in the face of land-use and climate change. Alternative connectivity assessments conducted at multiple spatial scales are needed to understand consequences of varying assumptions and for use in multi-scale conservation planning. Objectives We compared mapped output from different model scenarios conducted to identify areas important for ecological connectivity across North America. We asked how areas important for connectivity vary with spatial scale and assumptions regarding the way in which human modification affects landscape resistance. Methods We conducted a factorial experiment using omnidirectional connectivity analyses across North America where we crossed “treatments” represented by four moving window sizes and three resistance surfaces. The three resistance surfaces represent a gradient in species’ sensitivity to human modification. Results Maps of connectivity importance varied among scenarios. The effects of moving window size were more conspicuous than effects of different resistance surfaces. Outputs from small moving windows revealed mottled patterns of connectivity importance, while outputs from larger moving windows revealed broad swaths of connectivity importance across mountainous and boreal areas of North America. Patterns of connectivity importance tended to be more channelized from resistance surfaces produced to represent more human-sensitive species and more diffuse from resistance surfaces produced to represent more human-tolerant species. Conclusions Our scenarios and output represent alternative hypotheses and predictions about how multiple species may move in response to varying degrees of human modification. Our output can be compared to species-specific models to investigate which of our scenarios best matches observed movements of organisms. Our output can also be used as coarse-filter and multi-scale connectivity assessments for conservation plans. Notably, our outputs highlight the importance of small and isolated fragments of relatively natural land while simultaneously identifying broad regions important for maintaining connectivity across natural areas of North America.

Despite striking global change, management to ensure healthy landscapes and sustained natural resources has tended to set objectives on the basis of the historical range of variability in stationary ecosystems. Many social–ecological systems are moving into novel conditions that can result in ecological transformation. We present four foundations to enable a transition to future-oriented conservation and management that increases capacity to manage change. The foundations are to identify plausible social–ecological trajectories, to apply upstream and deliberate engagement and decision-making with stakeholders, to formulate management pathways to desired futures, and to consider a portfolio approach to manage risk and account for multiple preferences across space and time. We use the Kenai National Wildlife Refuge in Alaska as a case study to illustrate how the four foundations address common land management challenges for navigating transformation and deciding when, where, and how to resist, accept, or direct social–ecological change.

Understanding how abiotic disturbance and biotic interactions determine pollinator and flowering‐plant diversity is critically important given global climate change and widespread pollinator declines. To predict responses of pollinators and flowering‐plant communities to changes in wildfire disturbance, a mechanistic understanding of how these two trophic levels respond to wildfire severity is needed. We compared site‐to‐site variation in community composition (β‐diversity), species richness and abundances of pollinators and flowering plants among landscapes with no recent wildfire (unburned), mixed‐severity wildfire and high‐severity wildfire in three sites across the Northern Rockies Ecoregion, USA. We used variation partitioning to assess the relative contributions of wildfire, other abiotic variables (climate, soils and topography) and biotic associations among plant and pollinator composition to community assembly of both trophic levels. Wildfire disturbance generally increased species richness and total abundance, but decreased β‐diversity, of both pollinators and flowering plants. However, reductions in β‐diversity from wildfire appeared to result from increased abundances following fires, resulting in higher local species richness of pollinators and flowers in burned than unburned landscapes. After accounting for differences in abundance, standardized effect sizes of β‐diversity were higher in burned than unburned landscapes, suggesting that wildfire enhances non‐random assortment of pollinator and flowering‐plant species among local communities. Wildfire disturbance mediated the relative importance of mutualistic associations to β‐diversity of pollinators and flowering plants. The influence of pollinator β‐diversity on flowering‐plant β‐diversity increased with wildfire severity, whereas the influence of flowering‐plant β‐diversity on pollinator β‐diversity was greater in mixed‐severity than high‐severity wildfire or unburned landscapes. Moreover, biotic associations among pollinator and plant species explained substantial variation in β‐diversity of both trophic levels beyond what could be explained by wildfire and all other abiotic and spatial factors combined. Synthesis. Wildfire disturbance and plant–pollinator interactions both strongly influenced the assembly of pollinator and flowering‐plant communities at local and regional scales. However, biotic interactions were generally more important drivers of community assembly in disturbed than undisturbed landscapes. As wildfire regimes continue to change globally, predicting its effects on biodiversity will require a deeper understanding of the ecological processes that mediate biotic interactions among linked trophic levels.

Inventoried roadless areas (IRAs) in national forests in the contiguous United States (CONUS) are public lands that are ecologically intact and could be prime candidates for addition to the protected-area system, thereby contributing to the goal of protecting 30% of the Earth by 2030. Despite calls both to protect roadless areas and to downgrade them, we know surprisingly little about the importance of IRAs as habitat for vulnerable wildlife species. We assessed the importance of IRAs—in total and individually—as habitat for wildlife species of conservation concern (SCCs) and, for context, compared their habitat value to that of other national forest lands and CONUS lands in general. We also quantified how well the protected-area system would provide habitat for wildlife SCCs if all unprotected IRAs were added to it. Of the 537 wildlife SCCs in CONUS, 308 species (57%) have at least some suitable habitat in one or more IRAs. The median IRA contains suitable habitat for 10 wildlife SCCs, with a maximum of 62 wildlife SCCs. Despite their geographic and elevational clustering and predominance of a single biome type, IRAs provide a larger proportion of suitable habitat for multiple wildlife SCCs than non-IRA CONUS lands. The median number of wildlife SCCs’ suitable habitat per 900-m2 pixel is also slightly higher in IRAs than in most national forest wilderness areas, national monuments, and other currently protected areas. If all IRAs were added to the protected-area system in CONUS, there would be a substantial decrease (-38) in the number of wildlife SCCs that are currently considered “poorly represented” in protected areas. In this study we provide quantitative information about the importance of IRAs as habitat for vulnerable wildlife species so that stakeholders, agency staff, and lawmakers can make informed choices about where to invest limited resources for conservation.

Wilderness areas are not immune to changes in land use, land cover, and/or climate. Future changes will intensify the balancing act of maintaining ecological conditions and untrammeled character within wilderness areas. We assessed the quantitative and spatial changes in land use, land cover, and climate predicted to occur in and around wilderness areas by (1) quantifying projected changes in land use and land cover around wilderness areas; (2) evaluating if public lands surrounding wilderness areas can buffer future land-use change; (3) quantifying future climate conditions in and around wilderness areas; and (4) identifying wilderness areas expected to experience the most change in land use, land cover, and climate. We used projections of land use (four variables), land cover (five variables), and climate (nine variables) to assess changes for 707 wilderness areas in the contiguous United States by mid-21st century under two scenarios (medium-low and high). We ranked all wilderness areas relative to each other by summing and ranking decile values for each land use, land cover, and climate variable and calculating a multivariate metric of future change. All wilderness areas were projected to experience some level of change by mid-century. The greatest land-use changes were associated with increases in agriculture, clear cutting, and developed land, while the greatest land cover changes were observed for grassland, forest, and shrubland. In 51.6% and 73.8% of wilderness areas, core area of natural vegetation surrounding wilderness was projected to decrease for the medium-low and high scenarios, respectfully. Presence of public land did not mitigate the influence of land-use change around wilderness areas. Geographically, projected changes occurred throughout the contiguous U.S., with areas in the northeast and upper Midwest projected to have the greatest land-use and climate change and the southwestern U.S. projected to undergo the greatest land cover and climate change. Our results provide insights into potential future threats to wilderness areas and the challenges associated with wilderness stewardship and climate adaptation. Despite the high degree of protection and remoteness of wilderness areas, effective management and preservation of these lands must consider future changes in land use, land cover, and climate.

Connecting protected areas remains an important global conservation strategy in the face of ongoing and future threats to biodiversity. Amid our growing understanding of how species’ distributions will respond to climate change, conservation scientists need to plan for connectivity conservation across entire continents. We modeled multiscale connectivity priorities based on the least human‐modified lands between large protected areas of North America using least‐cost and circuit theory approaches. We first identified priority corridors between large protected areas, then characterized the network’s structure to unveil priority linkages most important for maintaining network‐ and regional‐level connectivity. Agreement between least‐cost corridors and current flow varied throughout North America, reflecting permeable landscape conditions and “pinch points” where potential ecological flows may concentrate between protected areas. Priority network‐level linkages derived from each approach were similar throughout the continental network (e.g., Rocky Mountains and Canadian boreal), but critical linkages that bridged regional protected‐area networks varied. We emphasize the importance of planning for connectivity at continental scales and demonstrate the utility of multiple methods when mapping connectivity priorities across large spatial extents with wide gradients in landscape conditions.

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International and national initiatives aim to conserve at least 30% of lands and waters by 2030. To safeguard biodiversity, conservation actions must be distributed in places that represent ecosystem and species diversity. Various methods of prioritizing sites for conservation have been used in local and global assessments. However, the performance and consequences of alternative methods are usually unknown. Such comparisons are needed to confidently implement national and international conservation initiatives. Here, we compared four widely-used methods of prioritizing sites in the contiguous United States for conserving species of mammals, birds, amphibians, and reptiles. Specifically, we calculated and mapped species richness, rarity-weighted richness, and two complementarity-based prioritizations (additive benefit function [ABF] and core area zonation [CAZ] in the software Zonation). We compared maps derived from these alternatives with respect to spatial locations and overlap, patch size distributions of the top-30% priorities, and existing ownership and protected-area status. We used species-accumulation curves across ranked priorities to evaluate performance of methods and compared results at 30% total area. Mapped locations and patch sizes of the highest priorities varied by taxonomic class and method of prioritization. Complementarity-based methods (ABF and CAZ) more efficiently represented species than methods based on richness or rarity-weighted richness, especially for taxa with higher beta diversity (amphibians). ABF and CAZ methods also resulted in greater conservation opportunity for the top 30% of priorities compared to maps of richness. Area-based conservation targets, such as the “30 by 30” initiative, must distribute limited resources in ways that safeguard all species. Our results show that spatial locations and configuration, performance, and conservation opportunity vary among prioritization methods and taxonomic classes.

As approaches to ecological restoration become increasingly large scale and collaborative, there is a need to better understand social aspects of restoration and how they influence land management. In this article, we examine social perspectives that influence the determination of ecological reference conditions in restoration. Our analysis is based on in‐depth interviews with diverse stakeholders involved in collaborative restoration of fire‐adapted forest landscapes. We conducted interviews with 86 respondents from six forest collaboratives that are part of the U.S. Forest Service's Collaborative Forest Landscape Restoration Program. Collaboratives use a variety of approaches to develop reference conditions, including historic, contemporary, and future scenarios. Historical conditions prior to European settlement (nineteenth century or “pre‐settlement” conditions), or prior to more recent grazing, logging, and exclusion of fire, were the predominant type of reference used in all sites. Stakeholders described benefits and limitations of reference conditions. Primary benefits include (1) providing a science‐based framework for bringing stakeholders together around a common vision; (2) gaining social understanding and acceptance of the underlying need for restoration; and (3) serving to neutralize otherwise value‐laden discussions about multiple, sometimes competing, resource objectives. Limitations stem from (1) concerns over social conflict when reference conditions are perceived to contradict other stakeholder values and interests, (2) differing interpretations of reference condition science, (3) inappropriate application or over‐generalization of reference information, and (4) limited relevance of historical references for current and future conditions in some ecosystems. At the same time, collaboratives are adopting innovative strategies to address conceptual and methodological limitations of reference conditions.

Precommercial thinning (PCT) is used to increase tree size and shorten harvest rotation time. Short-term results from PCT studies often show a trade-off between individual-tree growth and net stand yield, while longer-term effects of PCT on tree growth and stand yield are less well documented. We used a 54-year-old PCT study to test long-term effects of forest density and thinning schedules on stand yield and tree-level characteristics in even-aged western larch (Larix occidentalis Nutt.) stands. The study has three target densities (494, 890, and 1680 trees·ha−1) crossed with three thinning schedules (target density achieved through one, two, or four entries). Analysis of variance (ANOVA) and linear contrasts were used to test the effects of density and number of entries on tree- and stand-level attributes. Thinning before stand age 10 years leads to long-term constant yield (219.0–269.5 m3·ha−1; P > 0.05) across the tested densities. We also found constant volume growth across stand densities during the most recent measurement interval (5.42–6.41 m3·ha−1·year−1; P > 0.05). Number of entries did not affect any tree- or stand-level attribute. The primary effect of early PCT is to control whether wood volume and growth are concentrated on few large, stable trees or spread over many small, unstable trees.

Current systems of conservation reserves may be insufficient to sustain biodiversity in the face of climate change and habitat losses. Consequently, calls have been made to protect Earth's remaining wildlands and complete the system of protected areas by establishing conservation reserves that (1) better represent ecosystems, (2) increase connectivity to facilitate biota movement in response to stressors including climate change, and (3) promote species persistence within intact landscapes. Using geospatial data, we conducted an assessment for expanding protected areas within the contiguous United States to include the least human-modified wildlands, establish a connected network, and better represent ecosystem diversity and hotspots of biodiversity. Our composite map highlights areas of high value to achieve these goals in the western United States, where existing protected areas and lands with high ecological integrity are concentrated. We also identified important areas in the East rich in species and containing ecosystems that are poorly represented in the existing protected area system. Expanding protection to these priority areas is ultimately expected to create a more resilient system for protecting the nation's biological heritage. This expectation should be subject to rigorous testing prior to implementation, and regional monitoring will ensure areas and actions are adjusted over time.

Mounting concerns about global climate change have increased interest in the potential to use common forest management practices, such as forest density management with thinning, in climate change mitigation and adaptation efforts. Long-term effects of forest density management on total aboveground C are not well understood, especially for precommercial thinning (PCT) implemented very early in stand development. To assess the climate change mitigation potential of PCT, as well as tradeoffs with climate change adaptation, we examined total aboveground C stores in a 54-year-old western larch (Larix occidentalis Nutt.) precommercial thinning experiment to determine how different PCT treatments affect long-term aboveground C storage and distribution among pools. Four aboveground C pools (live overstory, live understory/mid-story, woody detritus, and forest floor) were measured and separated into C accumulated prior to initiation of the current stand (legacy C) and C accumulated by the current stand (non-legacy C). PCT had no influence on the total non-legacy aboveground C stores 54 years after treatment. Live tree C was nearly identical across densities due to much larger trees in low density treatments. Low density stands had more understory and mid-story C while unthinned plots had significantly more non-legacy woody detritus C than thinned stands. Legacy pools did not vary significantly with density, but made up a substantial proportion of aboveground C stores. We found that: (1) fifty-four years after PCT total aboveground C is similar across treatments, due primarily to the increase in mean tree C of trees grown at lower stand densities; (2) deadwood legacies from the pre-disturbance forest still play an important role in long-term C storage 62 years after current stand initiation, accounting for approximately 20–25% of aboveground C stores; and (3) given enough time since early thinning, there is no trade-off between managing stands to promote individual tree growth and development of understory vegetation, and maximizing stand level accumulation of aboveground C over the long term. We infer that early PCT can be used to simultaneously achieve climate change mitigation and adaptation objectives, provided treatments are implemented early in stand development before canopy closure and the onset of intense intertree competition.

Fil: Komatsu, Kimberly J. Smithsonian Environmental Research Center, Edgewater. United States. Fil: Avolio, Meghan L. Johns Hopkins University. Department of Earth and Planetary Sciences. Baltimore, United States. Fil: Lemoine, Nathan P. Marquette University. Department of Biological Sciences. Milwaukee, United States. Fil: Chaneton, Enrique José. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina. Fil: Chaneton, Enrique José. CONICET – Universidad de Buenos Aires. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina. Fil: Tognetti, Pedro Maximiliano.Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina. Fil: Tognetti, Pedro Maximiliano.CONICET – Universidad de Buenos Aires. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina. Fil: Yahdjian, María Laura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina. Fil: Yahdjian, María Laura. CONICET – Universidad de Buenos Aires. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina. Fil: Isbell, Forest. University of Minnesota. Department of Ecology, Evolution and Behavior. Saint Paul, United States. Fil: Grman, Emily. Eastern Michigan University. Department of Biology. Ypsilanti, United States. Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of CDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unprecedented global synthesis of over 100 experiments that manipulated factors linked to GCDs, we show that herbaceous plant community responses depend on experimental manipulation length and number of factors manipulated. We found that plant communities are fairly resistant to experimentally manipulated GCDs in the short term ( minor to 10 y). In contrast, long-term (major or equal to 10 y) experiments show increasing community divergence of treatments from control conditions. Surprisingly, these community responses occurred with similar frequency across the GCD types manipulated in our database. However, community responses were more common when 3 or more GCDs were simultaneously manipulated, suggesting the emergence of additive or synergistic effects of multiple drivers, particularly over long time periods. In half of the cases, GCD manipulations caused a difference in community composition without a corresponding species richness difference, indicating that species reordering or replacement is an important mechanism of community responses to GCDs and should be given greater consideration when examining consequences of GCDs for the biodiversity–ecosystem function relationship. Human activities are currently driving unparalleled global changes worldwide. Our analyses provide the most comprehensive evidence to date that these human activities may have widespread impacts on plant community composition globally, which will increase in frequency over time and be greater in areas where communities face multiple GCDs simultaneously. tbls., grafs.

Before the advent of intensive forest management and fire suppression, western North American forests exhibited a naturally occurring resistance and resilience to wildfires and other disturbances. Resilience, which encompasses resistance, reflects the amount of disruption an ecosystem can withstand before its structure or organization qualitatively shift to a different basin of attraction. In fire-maintained forests, resilience to disturbance events arose primarily from vegetation pattern-disturbance process interactions at several levels of organization. Using evidence from 15 ecoregions, spanning forests from Canada to Mexico, we review the properties of forests that reinforced qualities of resilience and resistance. We show examples of multi-level landscape resilience, of feedbacks within and among levels, and how conditions have changed under climatic and management influences. We highlight geographic similarities and important differences in the structure and organization of historical landscapes, their forest types, and in the conditions that have changed resilience and resistance to abrupt or large-scale disruptions. We discuss the role of the regional climate in episodically or abruptly reorganizing plant and animal biogeography and forest resilience and resistance to disturbances. We give clear examples of these changes and suggest that managing for resilient forests is a construct that strongly depends on scale and human social values. It involves human communities actively working with the ecosystems they depend on, and the processes that shape them, to adapt landscapes, species, and human communities to climate change while maintaining core ecosystem processes and services. Finally, it compels us to embrace management approaches that incorporate ongoing disturbances and anticipated effects of climatic changes, and to support dynamically shifting patchworks of forest and non-forest. Doing so could make these shifting forest conditions and wildfire regimes less disruptive to individuals and society.

Sustaining biodiversity depends on conservation actions coordinated at spatial extents large enough to maintain ecological processes. Numerous conservation prioritizations have been conducted resulting in gridded maps of pixels representing importance. However, it is not always clear how to move from priority pixels to landscape conservation designs, as pixels do not represent tangible, coherent landscapes for conservation attention. We attempted to move from pixels to landscapes by locating patches of high value pixels and overlaying level IV ecoregions from the United States Environmental Protection Agency (EPA) to delineate 74 landscapes ranging from 2927 to 95,962 km2. These landscapes were delineated to represent large areas of high wildland conservation value on which landscape conservation plans could focus, but where such plans would be embedded in national conservation priorities. After delineating landscapes, we assessed how well they represented the highest value areas with respect to ecological integrity, connectivity value, ecosystem representation priority, and biodiversity priority. We also assessed socio-economic condition of people within landscapes by evaluating economic and demographic data for counties within and adjacent to landscapes. Landscapes represented well high value lands with respect to ecological integrity, connectivity, and the composite wildland value, but poorly captured the highest value places with respect to ecosystem representation priority in the nation’s protected area system. Land ownership and protected status of landscapes varied from

The national historic trails in the National Trails System of the United States are designated with the purpose of identifying and protecting historic routes and their artifacts for public use and enjoyment. In 1978, the Lewis and Clark National Historic Trail was established to commemorate the expedition of 1804–1806 through preservation of historical, cultural, and natural resources. We conducted a quantitative assessment of the condition and character of the landscape immediately surrounding the Trail. Specifically, we investigated the composition of land cover and status of vegetation condition, as well as the proportions of the trail passing through federal, state, and private ownership with various levels of conservation protections. We used a national index of “wildness” (i.e., ecological condition and impact of human development) to summarize landscape qualities and identify the wildest sections along the Trail. Much of the Trail has been altered through agricultural development and land use, but several areas remain relatively wild. Most of the Trail passes through land with no known conservation strategy and very little passes through wilderness or national parks. We did identify several areas where the Trail passes through existing federal land administered as “roadless” where permanent legislative protections could ensure the remaining wild and intact lands be preserved for future generations.

Collaborative approaches to natural resource management are becoming increasingly common on public lands. Negotiating a shared vision for desired conditions is a fundamental task of collaboration and serves as a foundation for developing management objectives and monitoring strategies. We explore the complex socio-ecological processes involved in developing a shared vision for collaborative restoration of fire-adapted forest landscapes. To understand participant perspectives and experiences, we analyzed interviews with 86 respondents from six collaboratives in the western U.S., part of the Collaborative Forest Landscape Restoration Program established to encourage collaborative, science-based restoration on U.S. Forest Service lands. Although forest landscapes and group characteristics vary considerably, collaboratives faced common challenges to developing a shared vision for desired conditions. Three broad categories of challenges emerged: meeting multiple objectives, collaborative capacity and trust, and integrating ecological science and social values in decision-making. Collaborative groups also used common strategies to address these challenges, including some that addressed multiple challenges. These included use of issue-based recommendations, field visits, and landscape-level analysis; obtaining support from local agency leadership, engaging facilitators, and working in smaller groups (sub-groups); and science engagement. Increased understanding of the challenges to, and strategies for, developing a shared vision of desired conditions is critical if other collaboratives are to learn from these efforts.

Collaborative natural resource management has emerged as a means to increase the transparency of decisionmaking in public lands management and to promote shared learning among stakeholders. We developed a rapid forest assessment (RFA) approach for monitoring the key characteristics of forests that capitalizes on the growing interest for citizen science monitoring and can be implemented at large extents. The methods were designed for use with minimal training, to maximize field efficiency, and to simplify interpretation of the data. We chose our variables based on the common interests and questions of collaborative groups. We collected data on trees, fuels, woody debris, understory, horizontal cover, weeds, and soil disturbance. We tested the methods with several student groups and quantified the variability of measures within groups. We discuss the benefits of and challenges to engaging citizen scientists in monitoring. The simplicity and efficiency of the RFA make it a useful tool for multiparty monitoring.

Nearly a century of fire suppression in most forested land of the United States has limited researchers’ ability to construct and rigorously test conceptual models of forest structural development in mixed-conifer ecosystems. As a result, land managers must rely on conceptual models of forest development that may overemphasize idealized stand structures and developmental pathways, which ultimately hampers management of many forest systems for resilience to future climate change impacts. We sought to determine the relative importance of fire history (frequency, severity, and time since fire) and biophysical variables on forest structural diversity and development. Importantly, we conducted our study in an ecosystem with a contemporary active fire regime where wildland fire has been managed as an ecosystem process for four decades. Using data from unburned (≥80 years since fire), once-burned and twice-burned mixed-conifer forests in the Bob Marshall Wilderness of Northwest Montana, we conducted a hierarchical clustering analysis to identify forest stand structure classes. We then used a Classification and Regression Tree analysis, combined with other post-hoc analyses, to elucidate the biophysical and disturbance history drivers that lead to each structure class. The cluster analysis revealed six forest structure classes. The CART analysis indicated that time since fire plays a large role in determining forest structure, but at intermediate time scales structure is further shaped by repeat fires and interactions with biophysical variables. The CART and post-hoc analyses did not, however, indicate a singular fire history or biophysical pathway to any one structure class. We synthesize our results in a conceptual model of forest structural development under an active fire regime. This model supports existing theory that succession following severe fire plays a large role in shaping forest structure. It also recognizes the role of fire at variable severities and frequencies, the physical environment, and tree community composition in influencing forest structural development. The complexity of forest structure and development generated by an active fire regime points to the need to incorporate a process-based view of wildfire if the goal is to manage for improved resiliency and adaptive capacity to future climate change impacts.

Although they are the foundations of most efforts to conserve biodiversity, protected areas in the United States have, historically, not always been located in the most important areas to accomplish this goal. We investigated the overlap between suitable habitat for wildlife species of conservation concern and the location of public and private highly protected areas to assess the degree to which current highly protected areas are providing fine-scale habitat for wildlife species of conservation concern, to explore the relationship between the size of total suitable habitat of a species and its vulnerability to extinction, and to identify the species that are poorly represented in highly protected areas and determine where their habitats overlap—i.e., where future protected areas may best be located. We found that nearly one third of terrestrial wildlife species in the contiguous U.S. are vulnerable to extinction and that even though there is a relationship between total suitable habitat area and vulnerability, we find that synthetic indices of endemism and rarity-weighted richness are not necessarily good indicators of whether a species will be of conservation concern. Of all 537 wildlife species of conservation concern, only 62 (11%) are well represented in highly protected areas. To increase representation of habitats of wildlife species of conservation concern, scientists and managers should look to preserve lands where there is the greatest overlap among habitats for species of concern that are currently poorly represented in the reserve system, with special focus on species with small ranges on public lands.

Ecologists have studied geographic gradients in biodiversity for decades and recently mapped the intensity of the “human footprint” around the planet. The combination of these efforts have identified some global hotspots of biodiversity that are heavily impacted by human-caused land cover change and infrastructure. However, other hotspots of biodiversity experience less intense modifications from humans. Relationships between species diversity and the human footprint may be driven by covarying factors, like climate, soils, or topography, that coincidentally influence patterns of biodiversity and human land use. Here, I investigated relationships between tree species richness and the degree of human modification among Forest Service ranger districts within the contiguous US. Ranger districts with more tree species tended to experience greater human modification. Using data on climate, soils, and topography, I explored mechanisms explaining the positive relationship between tree richness and human modification. I found that climate is related to both tree richness and human modification, which may be indirectly mediated through climate’s role governing productivity. Ranger districts with more productive climates support more species and greater human modification. To explore potential conservation consequences of these relationships, I also investigated whether the amount of area designated within highly protected conservation lands were related to climate, productivity, and topography. Less productive ranger districts with steeper slopes tended to experience the greatest relative amounts of conservation protection. Combined, these results suggest that complex relationships explain the geographic patterns of biodiversity and the human footprint, but that climate and topography partially govern patterns of each.

Addressing uncertainties in climate vulnerability remains a challenge for conservation planning. We evaluate how confidence in conservation recommendations may change with agreement among alternative climate projections and metrics of climate exposure. We assessed agreement among three multivariate estimates of climate exposure (forward velocity, backward velocity, and climate dissimilarity) using 18 alternative climate projections for the contiguous United States. For each metric, we classified maps into quartiles for each alternative climate projections, and calculated the frequency of quartiles assigned for each gridded location (high quartile frequency = more agreement among climate projections). We evaluated recommendations using a recent climate adaptation heuristic framework that recommends emphasizing various conservation strategies to land based on current conservation value and expected climate exposure. We found that areas where conservation strategies would be confidently assigned based on high agreement among climate projections varied substantially across regions. In general, there was more agreement in forward and backward velocity estimates among alternative projections than agreement in estimates of local dissimilarity. Consensus of climate predictions resulted in the same conservation recommendation assignments in a few areas, but patterns varied by climate exposure metric. This work demonstrates an approach for explicitly evaluating alternative predictions in geographic patterns of climate change.

4 PREMISE OF THE STUDY: Geographic patterns of biodiversity have long inspired interest in processes that shape the assembly, diversity, and dynamics of communities at diff erent spatial scales. To study mechanisms of community assembly, ecologists often compare spatial variation in community composition (beta-diversity) across environmental and spatial gradients. These same patterns inspired evolutionary biologists to investigate how micro- and macro-evolutionary processes create gradients in biodiversity. Central to these perspectives are species interactions, which contribute to community assembly and geographic variation in evolutionary processes. However, studies of beta-diversity have predominantly focused on single tro- phic levels, resulting in gaps in our understanding of variation in species-interaction networks (interaction beta-diversity), especially at scales most rele- vant to evolutionary studies of geographic variation. METHODS: We outline two challenges and their consequences in scaling-up studies of interaction beta-diversity from local to biogeographic scales using plant-pollinator interactions as a model system in ecology, evolution, and conservation. KEY RESULTS: First, we highlight how variation in regional species pools may contribute to variation in interaction beta-diversity among biogeographic regions with dissimilar evolutionary history. Second, we highlight how pollinator behavior (host-switching) links ecological networks to geographic pat- terns of plant-pollinator interactions and evolutionary processes. Third, we outline key unanswered questions regarding the role of geographic variation in plant-pollinator interactions for conservation and ecosystem services (pollination) in changing environments. CONCLUSIONS: We conclude that the largest advances in the burgeoning fi eld of interaction beta-diversity will come from studies that integrate frame- works in ecology, evolution, and conservation to understand the causes and consequences of interaction beta-diversity across scales.

Identifying the drivers of tree mortality and survival is critical to developing conceptual and predictive models of fire effects on forest communities and landscapes. Individual tree characteristics (a function of species traits and tree size) govern tree- and community-scale mortality following fire, but mortality can also depend on tree density and effects arising from instantaneous extreme fire behavior. However, the relative importance and interaction of these factors are not well understood, especially for mixed-severity fire regimes. We sampled burned mixed-conifer forests dominated by western larch ( Larix occidentalis ) in the Bob Marshall Wilderness of Montana, U.S.A. We combined these field measurements with a remotely-sensed estimate of initial burn severity (dNBR) to test predictions about drivers of fire effects that produce heterogeneous post-fire tree and stand-level mortality. Tree survival 8–13 years after fire depended on complex interactions between species, size, and initial burn severity. Western larch experienced much higher survival than other tree species across tree sizes. Predictably, less fire-tolerant species experienced much lower survival than western larch. These tree-level probabilities in survival scale up to govern community-level mortality through variability in species composition. Greater relative abundance of fire-tolerant larch was associated with reduced levels of mortality at community scales. Interestingly, higher tree densities were either uncorrelated with community-level mortality or associated with lower community-level mortality. Our results show that traits of individuals can govern fire effects from trees to communities, and give rise to highly variable fire effects characteristic of mixed-severity fire.

Climate change challenges traditional strategies to conserve native biological diversity while sustaining ecosystem services. Several key climate adaptation frameworks call for adoption of experimental management whereby different strategies are viewed as experimental treatments requiring untreated controls by which to compare alternative approaches. At the same time, a variety of traditional conservation approaches (e.g., protecting land as connected network of reserves) continue to be emphasized as critical climate adaptation strategies, assuming that reserves are sufficiently representative of ecological diversity. Lands within the National Wilderness Preservation System could be used as untreated control landscapes while also serving as cores within protected area networks. The value of NWPS lands to serve as both untreated controls and representative ecological reserves will require maximizing ecological diversity within protected areas. Here, we assessed ecological representation across wil...

© 2015 The Author(s) Context: More than a century of forest and fire management of Inland Pacific landscapes has transformed their successional and disturbance dynamics. Regional connectivity of many terrestrial and aquatic habitats is fragmented, flows of some ecological and physical processes have been altered in space and time, and the frequency, size and intensity of many disturbances that configure these habitats have been altered. Current efforts to address these impacts yield a small footprint in comparison to wildfires and insect outbreaks. Moreover, many current projects emphasize thinning and fuels reduction within individual forest stands, while overlooking large-scale habitat connectivity and disturbance flow issues. Methods: We provide a framework for landscape restoration, offering seven principles. We discuss their implication for management, and illustrate their application with examples. Results: Historical forests were spatially heterogeneous at multiple scales. Heterogeneity was the result of variability and interactions among native ecological patterns and processes, including successional and disturbance processes regulated by climatic and topographic drivers. Native flora and fauna were adapted to these conditions, which conferred a measure of resilience to variability in climate and recurrent contagious disturbances. Conclusions: To restore key characteristics of this resilience to current landscapes, planning and management are needed at ecoregion, local landscape, successional patch, and tree neighborhood scales. Restoration that works effectively across ownerships and allocations will require active thinking about landscapes as socio-ecological systems that provide services to people within the finite capacities of ecosystems. We focus attention on landscape-level prescriptions as foundational to restoration planning and execution.

Protected areas, such as wilderness, form the foundation of most strategies to conserve biological diversity. However, the success of protected areas in achieving conservation goals depends partly on how well ecological diversity is represented in a network of designated lands. We examined how well the world’s largest highly-protected conservation network—the U.S. National Wilderness Preservation System (NWPS)—currently represents ecological systems found on federal lands in the contiguous United States and how ecological system representation has accumulated over the 50-year tenure of the Wilderness Act (passed in 1964 and giving the U.S. Congress authority to establish wilderness areas). Although the total area of NWPS has risen fairly steadily since 1964, the diversity of ecological systems accumulated in wilderness areas (436 ecological systems) reached an asymptote 30 years ago that is well below the total pool of ecological systems available (553) on federal lands. Thus, NWPS currently under-represents ecological system diversity. Additionally, only 113 ecological systems are represented at more than 20% of federal land area. As the designation of new wilderness areas becomes more difficult, it is important to increase the ecological representation of those areas to achieve greater protection of biological diversity. Over the next 50 years of the Wilderness Act, federal land-management agencies and the U.S. Congress could increase the ecological diversity of wilderness areas by prioritizing under-represented ecological systems in new wilderness legislation.

Conservation scientists recognize that additional protected areas are needed to maintain biological diversity and ecological processes. As regional conservation planners embark on recommending additional areas for protection in formal ecological reserves, it is important to evaluate candidate lands for their role in building a resilient protected areas system of the future. Here, we evaluate North Carolina’s Mountain Treasures with respect to their (1) ecological integrity, (2) role in connecting existing core protected areas, (3) potential to diversify the ecosystem representation of reserves, and (4) role in maintaining hotspots of biologically-rich areas that are not well protected. Mountain Treasures represent a citizen inventory of roadless areas and serve as candidates for elevated levels of conservation protection on U.S. federal lands. We compared Mountain Treasures to other candidate lands throughout the country to evaluate their potential national significance. While the Mountain Treasures tended to be more impacted by human modifications than other roadless areas, they are as important as other roadless areas with respect to their role in connecting existing protected areas and diversifying representation of ecosystems in conservation reserves. However, Mountain Treasures tended to have a much higher biodiversity priority index than other roadless areas leading to an overall higher composite score compared to other roadless areas. Our analysis serves as an example of how using broad-scale datasets can help conservation planners assess the national significance of local areas.