Predicting how climate change will influence forests is challenging. Forest communities are expected to lose cold-adapted trees near their low latitude/elevation range limits, while warm-adapted trees should increase in abundance near their high latitude/elevation limits ( i.e., ‘thermophilization’). However, slow-growing and long-lived trees, paired with climatic sensitivities that differ by species could add complexity to these predictions. To address these possibilities, we use demographic data collected from Mount Rainier National Park to examine: 1) the likelihood of rapid population growth or decline near range limits; 2) differences in climatic sensitivities between tree species at juvenile and adult stages; and 3) whether forest communities have already changed in response to recent warming. Our results suggest focal species are unlikely to shift their ranges rapidly with warming because recruit densities are low and time to reproductive maturity slow near upper range limits, while survival of adult trees is high near lower range limits. Additionally, focal tree species differ in the magnitude and strength of responses at seed and adult stages to climatic factors likely to be altered by warming. Consistent with these findings, shifts in forest community composition over the last 35 years were small, and not consistent with thermophilization predictions. In all, results imply that climate change will only have small, but unpredictable impacts on forest composition in the near-term. We discuss the possibility of much larger changes in forest composition with future climate change, if the drastically different climate regimes projected for the region fundamentally alter demographic processes and disturbance regimes.

It is hypothesized that climate impacts forest mosaics through dynamic ecological processes such as wildfires. However, climate-fire research has primarily focused on understanding drivers of fire frequency and area burned, largely due to scale mismatches and limited data availability. Recent datasets, however, allow for the investigation of climate influences on ecological patch metrics across broad regions independent of area burned and at finer scale. One area of particular interest is the distribution of fire refugia within wildfire perimeters. Although much recent research emphasis has been placed on high-severity patches within wildfires, unburned and low-severity patches provide critical remnant habitat and serve as seed sources to initiate colonization and succession in recently burned landscapes. These patches of persistence also may yield insights into approaches for developing fire-resilient landscapes by forest managers and communities seeking to reduce wildfire hazard. Here, we present results showing no decline in proportion of persistent patches in three study areas surrounding National Parks in the western United States, even as research and anecdotal information suggests that fires have become larger and more severe. We also show climate linkages to metrics of persistence that echo previous findings in climate-fire research, and we introduce a framework for addressing global change impacts on forest pattern more broadly. Specifically, we discuss the interactions of multiple drivers at landscape scales and the need to disaggregate relative influences using mixed methods that can address both social and ecological phenomenon.

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 wilderness, potential wilderness, and other lands located on the Flathead National Forest (FNF). Our aim was to quantify and map ecological cover types currently underrepresented in wilderness. Underrepresented land cover types included diverse low-elevation mixed-conifer forests. These cover types were well-distributed within potential wilderness, suggesting opportunities to expand untreated controls while diversifying ecological reserves. Investigating the proportion of potential wilderness composed of underrepresented ecosystems provides a means to prioritize areas for future wilderness recommendations. However, on the FNF large potential wilderness areas provide opportunities for significantly increasing the representation of individual ecosystems from minimal representation in wilderness. The method demonstrated here could be used in other national forest planning efforts to prioritize recommended wilderness based on increasing ecosystem representation at national and forest-wide scales.

When forest ecosystems develop over millennia, trees live five centuries, and mortality unfolds over decades, direct repeated observation (hereafter, longitudinal data) may be the only way to understand the fate of forests. Longitudinal data sets contribute greatly to our understanding, complementing experimental, modeling, and chronosequence approaches. Changing climate is changing forests, perhaps most rapidly through altered mortality regimes, and the elusive nature of integrated mechanistic understanding requires refinements and extensions to historically productive protocols. Changing climate reduces the inferential power of chronosequence techniques and changes model parameterization, and only some of the different factors contributing to tree mortality are expected to respond to climate variability and change. Because annual tree mortality rates are 5% to 1% for trees ≥ 1 cm dbh in young and old forests (respectively), detecting changes in mortality rates requires tracking thousands of trees, particularly to examine rare sub-populations of concern (e.g., large-diameter trees). And because mortality factors can be spatially aggregated and density-dependent, the causes and rates of tree mortality depend on the relationships between forest spatial structure and the direct and indirect effects of climate. Permanent plots with a combination of larger size, higher spatial precision, and greater sampling frequency will be required to further elucidate spatially explicit aspects of western forest demography. The combination of the longitudinal protocols developed by the Smithsonian Center for Tropical Forest Science, originally for studying tropical forest species diversity, and those developed by the US Geological Survey for annual tree mortality assessment together uniquely allow robust investigation of climate-mediated change in temperate forests.

Pacific lamprey (Entosphenus tridentatus) populations are declining and western brook lamprey (Lampetra richardsoni) status is unknown in the Pacific Northwest. Accurate measures of fish condition are a basic requirement to monitor health and status of fish populations. Fulton's condition factor has traditionally been used to assess condition of larval lamprey but alternative field-based and laboratory-based measures have not been assessed. We compared condition factor, body density, and lipid content of sympatric larval Pacific lamprey and western brook lamprey in 2010 and 2011 from two rivers of the Pacific Northwest. Condition factor was higher for Pacific lamprey than it was for western brook lamprey. All measures were variable and correlations among condition indices were weak. Body density and lipid content were higher in western brook lamprey in one year suggesting the possibility of increased energy requirements of metamorphosis to a nontrophic adult stage. The body density technique was onerous and likely has little field-based practicality. Body density and lipid content had a negative relationship as increased lipids leads to a more buoyant and less dense fish. Condition factor did not appear to be a good predictor of lipid content in our study and a suite of complex factors, including lipid dynamics prior to metamorphosis and nutritional resources, may underlie these results. This study provides one of the few empirical datasets on sympatric lampreys with different life history strategies.

Numerous species have been introduced to Coeur d'Alene Lake, Idaho over the last century, but minimal research has been completed to understand their population dynamics. The objective of this study was to describe the population demographics and dynamics of northern pike (Esox lucius) and smallmouth bass (Micropterus dolomieu), two important nonnative sport fishes in the system to provide information that will assist with guiding management decisions. The oldest northern pike was age 7 and the oldest smallmouth bass was age 11. Populations of both species exhibited very stable recruitment with a recruitment coefficient of determination of 0.99 for northern pike and 0.98 for smallmouth bass. Total annual mortality was estimated as 66% for northern pike and 42% for smallmouth bass. Growth of northern pike in Coeur d'Alene Lake was comparable to the 50–75th percentiles of growth exhibited by lentic northern pike populations across North America. Northern pike in Coeur d'Alene Lake were most similar to populations in the north-central and northeast United States with fast growth rates and short life spans. In contrast, smallmouth bass grew slowly and generally fell within the 5th percentile of lentic smallmouth bass populations in North America. Smallmouth bass in Coeur d'Alene Lake were similar to other populations in northern regions of the United States displaying slow growth rates with high longevity. Results of this study provide important insight on nonnative northern pike and smallmouth bass population dynamics.

Studies in Pacific Northwest riparian forests highlight the role of forest management in conserving target species, but rarely consider impacts on interspecies relationships such as pollination. We investigated plant-pollinator interactions among a native species of rove beetle, Pelecomalius testaceum, and a widespread native wetland plant species in the Pacific Northwest, Lysichiton americanus (western skunk cabbage), in an experimental framework comparing three riparian forest management regimes. Our study addressed the central question: what factors best predict pollinating beetle abundance on L. americanus in a managed Northwest landscape? We measured P. testaceum abundance on skunk cabbages in three riparian treatments in a managed forest: (1) an unlogged riparian zone, (2) a logged riparian zone with a limited buffer corridor, and (3) a clear-cut riparian zone with no remaining corridor. Across this diversity of forest treatments, we also measured inflorescence temperature, foliar damage, and plant sex. Beetle abundance was not responsive to forest management when compared across all sites, but was predictable by plant sex, geographic site, and foliar damage to plants. Beetle abundance was insensitive to temperature. Additionally, any potential responses to forest management were idiosyncratic and variable depending on plant sex. These results support the general idea that plant-pollinator interactions may be more dependent on traits of host plants than direct effects of forest management.