8413 research outputs found
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Context-dependent controls of periphyton across the littoral-benthic habitat of deep, clear lakes
No full textLittoral-benthic habitats can play a key role in governing whole ecosystem production within lakes. Typical controls of littoral-benthic production can include light, nutrients, and grazers, although, studies examining production across the photic zone in deep lakes are limited. This study investigates the role of nutrient limitation and inhibition from the shallow to deep (lower limit of the photic zone) littoral-benthic habitat of lakes with varying trophic states. To achieve this aim we use a combination of nutrient diffusing substrates (NDS), water column nutrient data, and photosynthetically active radiation (PAR) measurements. We observed that periphyton nutrient limitation and inhibition vary with depth and habitat. Differences were primarily driven by the concentration of dissolved inorganic nitrogen (DIN) and the availability of PAR. Less DIN and more PAR favored N limitation and P inhibition, whereas more DIN and less PAR favored P limitation and N inhibition. Furthermore, we found differences in nutrient limitation in the shallow littoral-benthic habitat of lakes may be affected by biological factors (density of high-level predators) than by surrounding substrate types, although these differences may have arisen from other, non-biological factors (e.g., nutrient supply from groundwater or surface runoff). Our findings reveal that periphyton nutrient responses across the littoral-benthic zone for clear lakes are context-dependent, influenced by a complex interplay of light and nutrient availability. The shifting roles of nitrogen and phosphorus across depth gradients call for a more nuanced understanding of periphyton responses in lakes with extensive photic zones. Considering the importance of littoral-benthic habitat for whole lake function, additional studies exploring the role of nutrient, light, and consumers should occur across depth for clear, deep-water lakes
Drought Information Needs of Pyramid Lake Paiute Tribe and Reno-Sparks Indian Colony
No full textAs droughts become more frequent, longer, and more intense, it becomes critical to identify drought impacts and the information needed to plan for and mitigate the effects of drought. The University of Nevada, Reno Extension is working to improve access to drought resources that better address the needs of Nevadans and provide decision-makers with more information about local drought concerns. Nationally, reservation lands are some of the most vulnerable to major climate change induced environmental changes. Focus groups with employees of the Pyramid Lake Paiute Tribe and Reno-Sparks Indian Colony reported drought impacts and information needs. Existing literature from guidance documents, tools, Tribal climate adaptation plans, and prior needs assessments served as the framework to identify gaps in information currently provided. While information needs expressed by the focus group participants reflected some of the topics identified in existing literature, the participating Tribal Nations have additional needs related to their specific social, political, and geographic situations. Focus group participants mostly use local drought indicators to respond to drought impacts. However, they reported having trouble finding additional information they need or might find useful. They suggested three ways to share information: 1. Having resources on a general Tribal related website like the Native American Fish and Wildlife Society 2. Through the support and dispersal of internal Tribal systems like their respective Tribal Council government and 3. A quarterly meeting of water purveyors, Tribal Nations and other users to report and share updates on water usage
Incorporating Natural Hazard Risk into Preservation Prioritization for Immovable Cultural Heritage in Louisiana
No full textCultural heritage possesses great value by connecting past, present, and future generations due to its historical, aesthetic, social, scientific, and spiritual significance. The state of Louisiana is rich in cultural heritage, containing 789 cultural resources documented by the Historic American Buildings Survey, Historic American Landscape Survey, and Historic American Engineering Record. While heritage is at risk of damage from several sources (e.g., human threat and degradation), natural hazards are a consistent and damaging risk to heritage. These natural hazards (e.g., hurricanes, flooding, etc.) are projected to increase in frequency and intensity with climate change, significantly impacting coastal areas. This study produces a spatial database and integrates a natural hazard risk component in order to inform the creation of priority categories for focused preservation efforts. Hotspot analysis is used to identify areas with clustering of very high-priority resources in order to target preservation efforts in areas where many highly at-risk cultural resources are located. This thesis revealed that Louisiana’s cultural resources are at most risk of future loss from hurricanes, riverine and coastal flooding, tornadoes, and strong wind. Overall, 26 resources are of ‘Very High’ priority for preservation and hotspot clusters emerge in the state’s southern portion. Including natural hazard risk in preservation decisions can be an important addition to cultural resource management strategy. This thesis advocates for continued inventorying and spatial location of cultural resources combined with risk mapping to enhance future preservation efforts
Exploring the use of seed coat enhancements in fecal seeding efforts for rangeland restoration and Cheatgrass seed viability post ruminal fermentation
No full textAs cheatgrass (Bromus tectorum) continues to establish itself as a prolific invader across the rangelands of North America, an abundance of fine fuel has resulted in a changing fire cycle. The intensification of these fires has led to the loss of key vegetative species, which destabilizes the landscape, putting ecological processes and rural communities at risk. To combat this destructive cycle, cattle can be utilized to mitigate cheatgrass encroachment by reducing fuel height and the seedbank through targeted grazing. Additionally, by supplementing the seeds of desirable rangeland species in the diet of cattle, the animals may serve as seed dispersal agents of these advantageous plant species through fecal material. The bovine rumen houses a highly adapted microbial consortium specialized in degrading fibrous material. The studies included in this thesis aimed to utilize in vitro and in situ methods to evaluate the effects that seed coat enhancements have on the viability of seed germination post ruminal fermentation. In addition, cheatgrass seeds were subjected to the same fermentation methods to understand how the rumen impacts the germination potential of this invasive annual grass species. The seeds of six target species, Indian ricegrass (Achnatherum hymenoides), crested wheatgrass (Agropyron cristatum), fourwing saltbrush (Atriplex canescens), bottlebrush squirreltail (Elymus elymoides), bluebunch wheatgrass (Pseudoroegneria spicata), and gooseberryleaf globemallow (Sphaeralcea grossulariifolia) were coated with either Polyvinylpyrrolidone (PVP) or PVP + ethyl cellulose (Ethocel). Our findings suggest that while PVP and PVP + Ethocel coating treatments resulted in decreased germination rates at time point 0 hours across most species, they ultimately exhibited greater resistance to microbial degradation through time. This demonstrates the potential compatibility of these coating treatments, specifically PVP + Ethocel, with rangeland species for fecal seeding projects. Additionally, our study found that cheatgrass seed viability was completely inhibited after 36 hours of ruminal fermentation, with fall harvested seeds exhibiting a slight lag in microbial degradation. These findings will play a pivotal role in the development of future land management and livestock grazing strategies for western rangelands
Border-Lines, Volume IX
No full textBorder-Lines is an interdisciplinary and intersectional academic journal dedicated to the dissemination of research on Chicana/o-Latina/o cultural, political and social issues. Border-Lines is a refereed journal that seeks to publish scholarly articles drawn from a variety of disciplines such as anthropology, education, geography, human health, literary and cultural studies, political science, social work and sociology
Post-Fire Restoration of Single-Leaf Pinyon Pine: Above-and Below-Ground Influences on Seedling Establishment
No full textRestoration of single-leaf pinyon pine (Pinus monophylla) in fire-affected dryland ecosystems is essential for maintaining biodiversity and preserving culturally significant landscapes, particularly for Indigenous communities who have traditionally relied on P. monophylla for food and for cultural practices. For the Washoe Tribe, whose ancestral lands encompass extensive areas of pinyon-dominated woodlands, the urgency of restoration is heightened by the the substantial proportion of these woodlands that has been lost to wildfires in recent decades, threatening both ecological resilience and cultural heritage. Increasing fire severity, exacerbated by climate change, invasive species, and habitat degradation, poses significant challenges for post-fire recovery of P. monophylla, a slow-growing species reliant on specific microsite conditions for successful regeneration. Collaborative efforts between local Indigenous communities, such as the Washoe Tribe, and universities emphasize the importance of engaging as equal partners in restoration, which fosters sustained and adaptive approaches tailored to the specific needs of fire-impacted ecosystems. This research, including a restoration trial on Washoe Tribal lands in the Pine Nut Mountains and an experimental study in the Tamarack Fire area in the Sierra Nevada, investigates the role of microsite conditions within a localized planting area, shade, and ectomycorrhizal fungi (EMF) inoculation in promoting P. monophylla seedling survival in challenging post-fire landscapes.In the Pine Nut study, 1,000 containerized seedlings were planted in post-fire microsites that were naturally shaded by shrubs, perennial grasses/forbs, and woody debris, as well as in open interspaces. Planted seedlings were located within seven sites spanning broad gradients of elevation and topography. Planting conditions were categorized to assess microsite and shade effects on survival, such as nurse type and canopy cover, while topographic factors, such as Topographic Position Index (TPI), were measured to determine abiotic influences. In the Tamarack study, a fully-crossed experimental design included 408 seedlings in three shade treatments (no shade, shade from a standing dead tree, and artificial shade cards) combined with two soil treatments (with and without non-burned soil from outside the burn area as an EMF inoculant). Seedling survival, EMF root colonization, and foliar traits (e.g., % N, δ¹³C) were monitored to assess the combined effects of abiotic and biotic restoration interventions.
Results from the Pine Nut study reveal that seedlings in shaded microsites—particularly under shrubs and perennial herbaceous vegetation —had a fivefold to sevenfold higher survival rate compared to those in open interspaces. Additionally, survival was positively associated with elevation, while the benefits of canopy cover varied by topographic position: shade had a more substantial effect for seedlings growing on ridgelines than in valleys. In the Tamarack study, shade also emerged as a critical factor leading to enhanced seedling survival and reduced drought stress. Non-burned soil addition increased EMF colonization and reduced foliar nitrogen but did not improve survival, suggesting that EMF effects may have been limited in our study. Shaded seedlings had reduced water stress as indicated by their more negative δ¹³C and higher foliar nitrogen levels, highlighting shade’s role in moderating extreme post-fire conditions.
These findings underscore the importance of strategic site selection and shade provision for P. monophylla restoration. In both studies, shade was shown to mitigate drought stress, a primary constraint in arid environments, while site-specific factors like elevation and topographic position inform optimal site selection. Although EMF inoculation showed limited direct survival benefits, it may enhance resource acquisition in other contexts. This research highlights the need for targeted, context-dependent restoration approaches that incorporate microsite and abiotic factors, integrating ecological knowledge with Indigenous land stewardship to support long-term restoration and cultural resilience in fire-impacted ecosystems
AIEI Webinar Series on Balanced Mix Design (Session 2 of 5): Validation
No full textThis webinar highlights the critical role of validation in the responsible implementation of balanced mix design (BMD). It emphasizes that validation is essential for establishing appropriate criteria. The presentation covers the reasons for conducting validation and provides examples of successful approaches adopted by various agencies.Federal Highway AdministrationU.S. Department of Transportatio
