Fire effects on aquatic ecosystems: an assessment of the current state of science

Fire is a prevalent feature of many landscapes and has numerous and complex effects on geological, hydrological, ecological, and economic systems. In some regions, the frequency and intensity of wildfire have increased in recent years and are projected to escalate with predicted climatic and landuse changes. In addition, prescribed burns continue to be used in many parts of the world to clear vegetation for development projects, encourage desired vegetation, and reduce fuel loads. Given the prevalence of fire on the landscape, authors of papers in this special series examine the complexities of fire as a disturbance shaping freshwater ecosystems and highlight the state of the science. These papers cover key aspects of fire effects that range from vegetation loss and recovery in watersheds to effects on hydrology and water quality with consequences for communities (from algae to fish), food webs, and ecosystem processes (e.g., organic matter subsidies, nutrient cycling) across a range of scales. The results presented in this special series of articles expand our knowledge of fire effects in different biomes, water bodies, and geographic regions, encompassing aquatic population, community, and ecosystem responses. In this overview, we summarize each paper and emphasize its contributions to knowledge on fire ecology and freshwater ecosystems. This overview concludes with a list of 7 research foci that are needed to further our knowledge of fire effects on aquatic ecosystems, including research on: 1) additional biomes and geographic regions; 2) additional habitats, including wetlands and lacustrine ecosystems; 3) different fire severities, sizes, and spatial configurations; and 4) additional response variables (e.g., ecosystem processes) 5) over long (>5 y) time scales 6) with more rigorous study designs and data analyses, and 7) consideration of the effects of fire management practices and policies on aquatic ecosystems

Publication Bias in the Performance Diagnostic Checklist and its Variations

Publication bias—selectively publishing studies with positive outcomes—poses a problem to science as it can lead to inaccurate reports of intervention effects. Sham and Smith (2014) found that the published and unpublished pivotal response treatment literature differed, calling for more investigation into behavior-analytic research for publication bias. In this study, comparisons between the published and unpublished literature on the Performance Diagnostic Checklist, Performance Diagnostic Checklist-Human Services, and the Performance Diagnostic Checklist-Safety were conducted across three effect size measures: percentage of non-overlapping data, improvement rate difference, and percentage of data exceeding the median. Generally published literature outperformed the unpublished literature, providing further evidence of an overselling of results in the field

Habitat Use of Wintering Henslow\u27s Sparrows (Centronyx henslowii) in Power Line Right-of-Ways

Habitat loss and degradation are the leading causes of grassland bird declines worldwide. The Henslow’s Sparrow (Centronyx henslowii; hereafter HESP) is a grassland bird species of conservation concern that has historically relied on the herbaceous ground-layer of longleaf pine savannas and similar habitats in the southeastern U.S. for food and shelter in the winter. However, due to human development, alterations of habitat, and fire suppression, only fragments of these habitats remain. Over the last decade, surveys have annually documented HESPs using power line right-of-ways (hereafter, ROWs) at several sites in the coastal plain of Georgia as alternative habitat for overwintering. These ROWs share similar vegetative characteristics to pine savannas because they are managed to have low tree cover and because they have a graminoid-dominated ground-layer. However, which micro-habitat characteristics HESPs select, and how much space they use within ROWs has not yet been studied. During the winters of 2019 to 2021, I captured HESPs at three Wildlife Management Areas and attached radio-transmitters to track their habitat selection and evaluate space use within ROWs. I conducted vegetation surveys in used and available habitat in the ROWs to assess which vegetation characteristics (e.g., height, density, composition) HESPs select. I used principal component analysis to reduce the number of vegetation variables and look for correlations among variables. I then used conditional logistic regression and model selection to identify top predictors of HESP habitat use. Statistical analyses showed that HESPs select areas within a ROW with a greater number of forb species, a small percentage of woody vegetation for escape refugia, and high vegetation density at the ground level. HESPs used less space (using 0.14 ha on average) than in longleaf pine savanna habitats, based on comparison with the literature. Based on these findings, I recommend habitat management practices that promote forb diversity, increase food resources, and maintain habitat structure. This study shows that ROWs can be important areas for conservation of overwintering HESPs. With continued management, ROWs can support overwintering grassland birds and could potentially act as corridors between longleaf pine restoration sites

Riparian Fuel Treatments in the Western USA: Challenges and Considerations

Fuel reduction treatments are being conducted throughout watersheds of the western United States to reduce hazardous fuels in efforts to decrease the risk of high-severity fire. The number of fuel reduction projects that include near-stream environments is increasing, bringing new challenges to riparian management. Riparian areas are protected by administrative regulations, some of which are largely custodial and restrict active management. However, riparian areas have also been affected by fire suppression, land use, and human disturbance, so manipulative treatments of vegetation and other fuels may be needed in some locations to maintain riparian biodiversity and restore valued functions. This report is a synthesis of current knowledge on the effects of wildfire and fuels treatments in riparian areas of the interior western United States, and includes the following: (1) a literature review of fire effects on riparian and aquatic characteristics and functions, provided as background for considering the need and potential impacts of fuel treatments; (2) a review of the potential effects of prescribed fire and mechanical treatments on riparian and aquatic resources and biota; (3) results of an online survey of resource managers, summarizing information about proposed and completed fuel reduction projects in riparian areas and wetlands in the interior west; (4) suggestions for pre- and post project-level monitoring for riparian fuels projects; and (5) a presentation of case studies, describing riparian fuel treatments with different objectives and methods. Research on the effects of fuel treatments on riparian and aquatic resources is limited, and monitoring of projects is highly encouraged, especially in watersheds supporting species of concern. Results of the online survey showed that habitat restoration is a common objective for many fuel treatments that include riparian areas; for each of the case studies, restoration of near-stream habitat for wildlife was a major goal. The integration of riparian fuel treatments with other aspects of fire and watershed management could potentially improve riparian condition in multiple stream and vegetation types

Relations among hydrology, soils, and vegetation in riparian meadows : influence on organic matter distribution and storage

Organic matter dynamics in riparian ecosystems are largely driven by interactions among hydrology, soil, and vegetation. In two riparian meadows, northeast Oregon, I examined the hypothesis that vegetation and soil characteristics in three plant communities - defined as wet, moist, and dry meadow - were strongly influenced by hydrological and redox variables associated with the geomorphological position of each community on the floodplain. Along short transects that extended from stream-side wet communities to terrace dry communities, I sampled plant species composition, biomass, and soil; calculated carbon and nitrogen pools; and monitored water table elevation, soil redox potential, and dissolved organic carbon (DOC) and nitrate-nitrogen (nitrate-N) in shallow ground water. Strong gradients in water table elevation and soil redox potential existed along the transects.. Water table elevation followed seasonal patterns of stream stage, and was consistently highest in wet communities, intermediate in moist communities, and lowest in dry communities. Soil redox potential indicated seasonal anaerobic conditions ([less than or equal to] 300 mV) in the wet and moist communities, and year-round aerobic conditions in the dry communities. Plant communities differed markedly in species richness (dry> moist> wet), total biomass (wet> moist> dry), and ratios of belowground-to-aboveground biomass (wet> moist> dry). Soil carbon and nitrogen pools were highest in dry communities and similar in wet and moist communities. Vegetation and soil characteristics were strongly correlated to median water table elevation and redox potential. Ecosystem (biomass + soil) carbon ranged from 7.01 to 11.7 kg/m², with [approximately] 2 to 4 % in aboveground biomass, [approximately] 2 to 23% in belowground biomass, and [approximately] 81 to 95% in soil. Ecosystem nitrogen ranged from 0.035 to 0.093 kg/m², with [approximately] 0.7 to 1.6 % in aboveground biomass, [approximately] 1.5 to 6 % in belowground biomass, and [approximately] 94 to 98% in soil. In shallow ground water, concentrations of DOC and nitrate-N were two to six times greater than in stream water, with highest values in wet communities. Collectively, these results indicate that, in unconstrained reaches, water table elevation and soil redox potential strongly influence distribution of plant species, and dynamics and storage of organic matter

A Guide to Fuels Management in Riparian Areas of the Interior West, Final Report

Fuel treatments in riparian areas pose distinct challenges. Riparian areas are protected by administrative regulations, many of which are largely custodial and restrict active management. However, riparian areas have also been affected by fire suppression, land use, and disturbance and manipulative treatments of fuels may be needed to maintain riparian biodiversity and restore valued functions. This project is a synthesis of the current knowledge regarding fuels treatments in riparian areas of the interior western USA. It summarizes the most recent scientific literature, but also incorporates the practical knowledge gained by resource managers who have been utilizing different techniques to reduce riparian fuels. Because riparian fuel treatments are a fairly new management strategy, we set out to document their frequency, extent, efficacy, and potential ecological effects on federal lands in the western United States by conducting an on-line survey of resource managers from the USDA Forest Service, and USDI Fish and Wildlife Service, Bureau of Land Management, and National Park Service. We found that active fuels management in riparian areas is increasingly common across all agencies, although about 70% of the treated riparian areas were included as part of upland projects. The most common primary project objectives were hazardous fuel reduction (57% of respondents) and habitat restoration (55% of respondents); however, most projects had multiple objectives. Although prescribed fire is the most frequently used treatment in riparian projects, treatment combinations—which include sequences of burning, mechanical thinning, scattering, and pile burning—are also common. Similar to upland projects, the primary constraint to planning and implementation is the potential occurrence of federally-listed species in the project area. Additional concerns and constraints varied with agency and region. Treating fuels in riparian areas is a topic where the state of the practice has preceded the state of the science. To incorporate practical knowledge, we selected projects from the survey participants, visited them to highlight as case studies, and present their on-the-ground lessons learned. Our primary deliverable will be a USDA Forest Service General Technical Report (GTR), where we will also present guidelines on how to integrate ecological knowledge and principles into planning and monitoring riparian fuels projects and provide recommendations for post-treatment streamside management

Assessing self–other agreement and dyadic adjustment in marital dyads

In this study, we examined self–other agreement in married couples to examine the association between their perceptions of self and other psychological problems and dyadic adjustment. We also postulated that dyadic adjustment would moderate self–other agreement ratings on low- and high-visibility traits of psychological problems. Using a cross-informant assessment design, 101 married dyads in three marital groups (non-clinical, transplant, and divorcing dyads) provided reciprocal self and other ratings for psychological problems. Self–other agreement indices were quantified using self–other differences scores and Pearson r, qualifying (Q) correlations. The self–other agreement models yielded significant differences in dyadic adjustment across couple types. Couples that demonstrated moderate to elevated levels of self–other agreement for psychological problems had higher levels of dyadic adjustment. Differences in self–other psychological problem ratings were robust predictors of dyadic maladjustment and poor relational quality. Dyadic adjustment was found to moderate self–other agreement for psychological problems, especially for wives’ appraisals and husbands’ attunement to wives’ low-visibility problems. The findings validate the impact of self–other agreement in models of relationship conflict and adjustment. Wive’s other views tended to have large effect sizes in dyadic adjustment. The study’s limitations and recommendations for future research are also discussed

A Noninvasive Method to Detect Mexican Wolves and Estimate Abundance

Monitoring wolf abundance is important for recovery efforts of Mexican wolves (Canis lupus baileyi) in the Blue Range Wolf Recovery Area in Arizona and New Mexico, USA. Although radiotelemetry has been a reliable method, collaring and tracking wolves in an expanding population will be prohibitively expensive and alternative methods to estimate abundance will become necessary. We applied 10 canid microsatellite loci to 235 Mexican wolf samples, 48 coyote (C. latrans) samples, and 14 domestic dog (C. lupus familiaris) samples to identify alleles that provide reliable separation of these species. We then evaluated an approach for prescreening, noninvasively collected DNA obtained from fecal samples to identify Mexican wolves. We generated complete genotypes for only those samples identified as probable Mexican wolves. We used these genotypes to estimate mark–recapture population estimates of Mexican wolves and compared these to known numbers of wolves in the study area.We collected fecal samples during 3 sampling periods in 2007–2008 and used Huggins-type mark–recapture models to estimate Mexican wolf abundance. We were able to generate abundance estimates with 95% confidence for 2 of 3 sampling periods. We estimated abundance to be 10 (95% Cl = 6–34) during one sampling period when the known abundance was 10 and we estimated abundance to be 9 (95% CI = 6 –30) during the other sampling period when the known abundance was 10. The application of this noninvasive method to estimate Mexican wolf abundance provides an alternative monitoring tool that could be useful for long-term monitoring of this and other recovering populations. Published 2016. This article is a U.S. Government work and is in the public domain in the USA

A Noninvasive Method to Detect Mexican Wolves and Estimate Abundance

Monitoring wolf abundance is important for recovery efforts of Mexican wolves (Canis lupus baileyi) in the Blue Range Wolf Recovery Area in Arizona and New Mexico, USA. Although radiotelemetry has been a reliable method, collaring and tracking wolves in an expanding population will be prohibitively expensive and alternative methods to estimate abundance will become necessary. We applied 10 canid microsatellite loci to 235 Mexican wolf samples, 48 coyote (C. latrans) samples, and 14 domestic dog (C. lupus familiaris) samples to identify alleles that provide reliable separation of these species. We then evaluated an approach for prescreening, noninvasively collected DNA obtained from fecal samples to identify Mexican wolves. We generated complete genotypes for only those samples identified as probable Mexican wolves. We used these genotypes to estimate mark–recapture population estimates of Mexican wolves and compared these to known numbers of wolves in the study area.We collected fecal samples during 3 sampling periods in 2007–2008 and used Huggins-type mark–recapture models to estimate Mexican wolf abundance. We were able to generate abundance estimates with 95% confidence for 2 of 3 sampling periods. We estimated abundance to be 10 (95% Cl = 6–34) during one sampling period when the known abundance was 10 and we estimated abundance to be 9 (95% CI = 6 –30) during the other sampling period when the known abundance was 10. The application of this noninvasive method to estimate Mexican wolf abundance provides an alternative monitoring tool that could be useful for long-term monitoring of this and other recovering populations. Published 2016. This article is a U.S. Government work and is in the public domain in the USA