Habitat conservation plans (HCPs) under the US Endangered Species Act have become an important conservation tool. For over two decades, the Washington State Department of Natural Resources (WDNR) has managed much of the state's forested lands under one of the largest and longest-running single-entity HCPs in existence, seeking to integrate timber harvest and other social–ecological values mostly related to structurally complex, older forest habitats. Here, we examine trends in older forest conditions on western Washington WDNR-managed lands relative to HCP expectations, using publicly available spatial datasets to compare trends in older forest area and connectivity before (1986–1999) and after (1999–2017) HCP implementation. Trends in both attributes changed markedly between the pre- and post-implementation periods, varying strongly with management intensity. Since 1999, total older forest area (i.e., that meeting structural index/ indicator thresholds) saw little net change (-38 ha·yr^-1, totaling -685 ha) across approximately 624,000 ha, but shifted spatially from WDNR's most intensively managed lands (-843 ha·yr^-1) to conservation-designated lands such as riparian (+552 ha·yr^-1) and mixed (with both harvest and habitat objectives) upland (+253 ha·yr^-1) areas. Similarly, older forest connectivity declined on lands primarily managed for timber but increased on all other lands managed less intensively. So far, the decades since HCP implementation largely have been a time of landscape reorganization—positioning the landscape consistent with HCP intentions to meet timber objectives while developing older forest habitat in designated areas into the future. This work illustrates a method to evaluate policy implementation and the likelihood of achieving HCP expectations over time.

Factors controlling mosses on the forest floor in western North America are poorly understood. We examined elevational distributions for six of the most abundant large forest floor mosses; based on those distributions, a transplant experiment of two species evaluated if interspecific interactions can be mediated by climatic context. Mosses had species-specific elevational profiles, with Rhytidiopsis robusta more prominent at higher elevations, while Hylocomium splendens, Kindbergia oregana, Rhytidiadelphus loreus, and Rhytidiadelphus triquetrus were more prominent at lower elevations. Homalothecium megaptilum was bimodal, peaking at middle and low elevations. We selected Rhytidiadelphus triquetrus and Rhytidiopsis robusta for a transplant experiment because each is prominent at different elevations and they are similar in stature. Moss mat squares cut from the forest floor at middle elevations were transplanted in a single- or mixed-species pattern at two sites, one high elevation and one low elevation. We recorded changes in percent cover within the squares over one year as well as outgrowth onto bare soil and litter. Hypothesized relative species performances based on elevational distributions were mostly not supported. The low-elevation associated species (Rhytidiadelphus triquetrus) outperformed the high-elevation species (Rhytidiopsis robusta) at the high-elevation site, both in a mixture and as a monoculture. At the lower site, Rhytidiadelphus triquetrus grew well in a mixture, but the monoculture declined. Furthermore, Rhytidiopsis robusta grew faster at low elevation than at high, both in a mixture and monoculture, despite being more abundant at high elevations. Poor performance of both species at high elevations raises interesting questions about what factors limit moss mats in general at higher elevations in the Cascade Range.

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Lake surface temperature (LST) is one of the key indicators required for ecological and hydrological studies and for water quality management. Satellite remote sensing of LST has high spatial and temporal coverage and can be a cost-effective method to monitor lakes. This study explores geophysical and meteorological factors that control LST by studying LST for 115 reservoirs in the Columbia River basin from 2000–2022. We found that climatic factors such as air temperature, vapor pressure deficit, and surface specific humidity explained up to 80% of the variability observed in LST. Precipitation, wind speed, wind direction, lake characteristics, and lake elevation appeared to have negligible influence on the temporal variability of LST for these Columbia basin reservoirs. Our study revealed that there is an overall increasing trend in LST between 2000 and 2022. In 66% of reservoirs, surfaces warmed annually at a mean rate of 0.25 °C per decade, while the remaining reservoirs cooled annually at a mean rate of 0.16 °C per decade. Low elevation reservoirs with small surface areas warmed the fastest, whereas surfaces of high elevation reservoirs had a cooling trend, especially for reservoirs with large surface areas. LST trends were insensitive to reservoir depth. Using the vantage of space and multi-decadal observations, this study presents a thorough overview of the thermal behavior of reservoir water surfaces in the Columbia River basin. The findings can build clear pathways to improving hydro-ecological studies and water management of the region that is drought-prone and impacted by climate change.

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The Humboldt marten (Martes caurina humboldtensis) has declined from over 95% of its historic range and currently occurs in just four extant population areas (EPAs). Prior to their listing under the Endangered Species Act, a conservation strategy was developed to identify key conservation needs for this species. This assessment identified an area near the California–Oregon (CA–OR) border as the second EPA in California, yet little was known about the overall distribution or habitat used by this population. This prompted our investigation to provide the first systematic survey of the CA–OR EPA and to assess habitat use using an occupancy modeling framework. Between 2017 and 2018 we surveyed 51 survey units in and adjacent to the EPA and detected martens at 20 units (39.2%). We found that occupancy by martens was most influenced by the amounts of low-elevation late-seral old-growth forest habitat, riparian habitat, and mid-seral forest habitat. The probability of occupancy by martens was greatest in low-elevation (< 800 m, Odds Ratio [OR] = 0.33, 95% Confidence Interval [CI] = 0.13–0.81) habitat and was positively associated with late-seral forest habitat at the 1,170 m home range scale (OR = 35.31, 95% CI = 1.30–958.07), riparian habitat at the 1,170 m home range scale (OR = 3.20, 95% CI = 1.01–10.1), and marginally by mid-seral forest habitat at the 50 m microhabitat scale (OR = 1.28, 95% CI = 0.95–1.73). Our findings identified habitat characteristics important for explaining the distribution of this understudied population, addressing two of the highest priority research needs identified in the Humboldt marten conservation strategy.

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To predict patterns of forest regeneration following wildfires, we must determine the factors that affect tree seedling establishment. We tested the relative influence of abiotic, biotic, and landscape factors on the probability of tree seedling presence in Waterton Lakes National Park, Alberta, Canada. We recorded the presence of seedlings in 98 plots that were first surveyed 25 years before the 2017 Kenow Wildfire, 53 of which burned in the fire. We included plots that did not burn to test the effect of the wildfire on seedling occurrence, and whether the importance of other factors varied in burned versus unburned plots. Lodgepole pine (Pinus contorta Douglas ex Loudon) seedlings occurred in about 25% of burned plots, but only 2% of unburned plots. Seedlings of poplars (Populus spp. Linnaeus), subalpine fir (Abies lasiocarpa (Hooker) Nuttall), and Engelmann spruce (Picea engelmannii Engelmann) occurred in 8% or less of the burned plots and 20% to 48% of unburned plots. After accounting for burn status, pine seedlings were more likely to occur in plots with higher herbaceous plant cover, while spruce seedling occurrence declined with elevation. After burn status, past presence of the tree species in a plot was the strongest predictor of seedling occurrence. However, seedlings of spruce and fir are still mostly absent from burned areas. Long-term monitoring of these plots will reveal whether these species can successfully recolonize burned areas, and how long it will take.