Faculty Publications
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Item Open Access Merging Indigenous knowledge systems and station observations to estimate the uncertainty of precipitation change in central Mongolia(Colorado State University. Libraries, 2018-08-19) Fassnacht, Steven R., author; Allegretti, Arren Mendezona, author; Venable, Niah B. H. author; Fernández-Giménez, María E., author; Tumenjargal, Sukh, author; Kappas, Martin author; Laituri, Melinda J., author; Batbuyan, Batjav, author; Pfohl, Anna K. D., author; MDPI, publisherAcross the globe, station-based meteorological data are analyzed to estimate the rate of change in precipitation. However, in sparsely populated regions, like Mongolia, stations are few and far between, leaving significant gaps in station-derived precipitation patterns across space and over time. We combined station data with the observations of herders, who live on the land and observe nature and its changes across the landscape. Station-based trends were computed with the Mann–Kendall significance and Theil–Sen rate of change tests. We surveyed herders about their observations of changes in rain and snowfall amounts, rain intensity, and days with snow, using a closed-ended questionnaire and also recorded their qualitative observations. Herder responses were summarized using the Potential for Conflict Index (PCI2), which computes the mean herder responses and their consensus. For one set of stations in the same forest steppe ecosystem, precipitation trends were similar and decreasing, and the herder-based PCI2 consensus score matched differences between stations. For the other station set, trends were less consistent and the PCI2 consensus did not match well, since the stations had different climates and ecologies. Herder and station-based uncertainties were more consistent for the snow variables than the rain variables. The combination of both data sources produced a robust estimate of climate change uncertainty.Item Open Access Fire, fuel, and climate interactions in temperate climates(Colorado State University. Libraries, 2025-01-23) Kampf, Stephanie K., author; Stevens‐Rumann, Camille S., author; Nunes, Leónia, author; Sequeira, Ana Catarina, author; Rego, Francisco Castro, author; Fernández, Cristina author; Hernández‐Duarte, Ana, author; Mosso, Clara E., author; Francois, Jean Pierre, author; Miranda, Alejandro, author; AGU, publisherTemperate regions around the world are experiencing longer fire weather seasons, yet trends in burned area have been inconsistent between regions. Reasons for differences in fire patterns can be difficult to determine due to variable vegetation types, land use patterns, fuel conditions, and human influences on fire ignition and suppression. This study compares burned areas to climate and fuel conditions in three temperate regions: the desert, shrub, and forest ecoregions of western North America, west‐central Europe, and southwestern South America. In each region the mean annual aridity index (AI, precipitation over potential evapotranspiration) spans arid to humid climates. We examined how the fraction of area burned from 2001 to 2021 varied with mean annual AI, mean aboveground biomass, and land cover type distributions. All three regions had low fractions of area burned for the driest climate zones (AI < 0.5), a sign of fuel limitation to burned area. Fraction of area burned increased with mean aboveground biomass for these dry zones. Fraction of area burned peaked at intermediate AI (0.7–1.5) for all regions and declined again in the wettest climate zones (AI > 1.5), a sign of climate limitation to burned area. Of the three regions, western North America had the highest burned area, fraction of area burned, and fire sizes. Fragmentation of vegetation patches by the high Andes Mountains in southwestern South America and by intensive land use changes in west‐central Europe likely limited fire sizes. All three regions are at risk for future wildfires, particularly in areas where fire is currently climate limited.Item Open Access Building capacity for individual and systems-level collaborative conservation impacts: intentional design for transformative practice(Colorado State University. Libraries, 2022-09-05) Hauptfeld, Rina S., author; Jones, Megan S., author; Skyelander, Kim, author; Taylor & Francis Group, LLC, publisherConservation for and with local communities and stakeholders is essential. Despite the importance of community-oriented approaches and calls for capacity building in conservation, the impacts and inputs of training in relational fields like collaborative conservation remain unclear. We used mixed methods to conduct one of the first evaluations of a collaborative conservation capacity building program, and present an empirically-based causal model of the programmatic inputs supporting long-term changes. We found moderate to transformational impacts on participants' practice and professional trajectories, and on multiple dimensions of capacity, including comfort, conviction, and identity. Flexible funding, immersion into a safe community of practice, and the obligation and opportunity to experiment with collaborative approaches fostered these changes. We also found evidence of a developing landscape of practice, and perceived benefits to communities where fellows worked. We suggest programs incorporate intentional design, including networked communities of practice and heuristics, to enhance individual and systems impact.Item Open Access Migration-land systems model: a theoretical agent-based model(2023) Warrier, Rekha, author; Boone, Randall, author; Salerno, Jonathan, authorThree specifications of MLSM that illustrate both model functionality as well as key interactions between migration decisions and land function change are included. The examples were developed using the agent-based modeling platform NetLogo (https://ccl.northwestern.edu/netlogo/) and rendered into HTML formats using NetLogo Web (https://www.netlogoweb.org/). No software installation is needed. Open the HTML files using a web browser and follow instruction included in the 'Model Info' tab at the bottom of the page. The full model is publicly available in Modeling Commons: https://modelingcommons.org/browse/one_model/7156#model_tabs_browse_info.Item Open Access Participatory mapping in Mongolia(Colorado State University. Libraries, 2022) Laituri, Melinda, author; Allegretti, Arren Mendezona, author; Batjav, Batbuyan, author; Baival, Batkhishig, authorThis record contains supporting documents associated with participatory mapping activities conducted as part of the Mongolian Rangelands and Resilience (MOR2) project. The collection of documents includes presentations, map images, a blog post, and a photo essay of the project.Item Open Access Strategic needs of water in the Yukon (SNOWY): participatory mapping in Alaska(Colorado State University. Libraries, 2022) Laituri, Melinda, authorAs part of the larger, NSF funded research project, Strategic Needs of Water on the Yukon (SNOWY), participatory mapping workshops were held in three villages (Kotlik, Chevak, St. Mary's) located in the lower Yukon River Basin and Yukon-Kuskokwim delta region of Alaska. The goal of these workshops was to create a suite of maps based on seasonal subsistence resource utilization and begin to assess changes to the winter climate in the Yukon. In concert with the maps, participants also created seasonal subsistence calendars listing resource utilization throughout the year and engaged in interviews to discuss seasonality. The research focused on the nature and degree of the relationship between seasonality and subsistence resource vulnerability. We used data collected through semi-structured interview, participatory mapping, and seasonal calendar workshops in three communities located in the Yukon River Delta (YRD) over the course of two weeks in February 2014 and a return visit in May 2014.Item Open Access Confounding factors in algal phosphorus limitation experiments(Colorado State University. Libraries, 2018-10-18) Beck, Whitney S., author; Hall, Ed K., author; PLOS ONE, publisherAssessing algal nutrient limitation is critical for understanding the interaction of primary production and nutrient cycling in streams, and nutrient diffusing substrate (NDS) experiments are often used to determine limiting nutrients such as nitrogen (N) and phosphorus (P). Unexpectedly, many experiments have also shown decreased algal biomass on NDS P treatments compared to controls. To address whether inhibition of algal growth results from direct P toxicity, NDS preparation artifacts, or environmental covariates, we first quantified the frequency of nutrient inhibition in published experiments. We also conducted a meta-analysis to determine whether heterotrophic microbial competition or selective grazing could explain decreases in algal biomass with P additions. We then deployed field experiments to determine whether P-inhibition of algal growth could be explained by P toxicity, differences in phosphate cation (K vs. Na), differences in phosphate form (monobasic vs. dibasic), or production of H2O2 during NDS preparation. We found significant inhibition of algal growth in 12.9% of published NDS P experiments as compared to 4.7% and 3.6% of N and NP experiments. The meta-analysis linear models did not show enhanced heterotrophy on NDS P treatments or selective grazing of P-rich algae. Our field experiments did not show inhibition of autotrophic growth with P additions, but we found significantly lower gross primary productivity (GPP) and biomass-specific GPP of benthic algae on monobasic phosphate salts as compared to dibasic phosphate salts, likely because of reduced pH levels. Additionally, we note that past field experiments and meta-analyses support the plausibility of direct P toxicity or phosphate form (monobasic vs. dibasic) leading to inhibition of algal growth, particularly when other resources such as N or light are limiting. Given that multiple mechanisms may be acting simultaneously, we recommend practical, cost-effective steps to minimize the potential for P- inhibition of algal growth as an artifact of NDS experimental design.Item Open Access Local knowledge production, transmission, and the importance of village leaders in a network of Tibetan pastoralists coping with environmental change(Colorado State University. Libraries, 2016) Hopping, Kelly A., author; Yangzong, Ciren, author; Klein, Julia A., author; Resilience Alliance, publisherChanging climate, social institutions, and natural resource management policies are reshaping the dynamics of social-ecological systems globally, with subsistence-based communities likely to be among the most vulnerable to the impacts of global change. These communities’ local ecological knowledge is increasingly recognized as a source of adaptive capacity for them as well as a crucial source of information to be incorporated into scientific understanding and policy making. We interviewed Tibetan pastoralists about their observations of environmental changes, their interpretations of the causes of these changes, and the ways in which they acquire and transmit this knowledge. We found that community members tended to agree that changing climate is driving undesirable trends in grassland and livestock health, and some also viewed changing management practices as compounding the impacts of climate change. However, those nominated by their peers as experts on traditional, pastoral knowledge observed fewer changes than did a more heterogeneous group of people who reported more ways in which the environment is changing. Herders mostly discussed these changes among themselves and particularly with village leaders, yet people who discussed environmental changes together did not necessarily hold the same knowledge of them. These results indicate that members of the community are transferring knowledge of environmental change primarily as a means for seeking adaptive solutions to it, rather than for learning from others, and that local leaders can serve as critical brokers of knowledge transfer within and beyond their communities. This highlights not only the interconnectedness of knowledge, practice, and power, but also points toward the important role that local governance can have in helping communities cope with the impacts of global change.Item Open Access Snow and albedo climate change impacts across the United States Northern Great Plains(Colorado State University. Libraries, 2015) Fassnacht, S. R., author; Cherry, M. L., author; Venable, N. B. H., author; Copernicus, publisherIn areas with a seasonal snowpack, a warmer climate would cause less snowfall, a shallower snowpack and a change in the timing of snowmelt. Trends in temperature, precipitation (total and as snow), days with precipitation and snow, and winter albedo were investigated over the 60 year period from 1951 to 2010 for 20 meteorological stations across the Northern Great Plains. This is an area where snow accumulation is shallow but persistent for most of the winter (November through March). The most consistent trends were minimum temperature and days with precipitation, which both increased at a majority of the stations. The modeled winter albedo decreased at more stations than where it increased. There were substantial spatial variability in the climate trends. For most variables, the period of record used influenced the magnitude and sign of the significant trends.Item Open Access Soil bacterial community composition altered by increased nutrient availability in Arctic tundra soils(Colorado State University. Libraries, 2014-10-02) Koyama, Akihiro, author; Wallenstein, Matthew D., author; Simpson, Rodney T., author; Moore, John C., author; Frontiers Research Foundation, publisherThe pool of soil organic carbon (SOC) in the Arctic is disproportionally large compared to those in other biomes. This large quantity of SOC accumulated over millennia due to slow rates of decomposition relative to net primary productivity. Decomposition is constrained by low temperatures and nutrient concentrations, which limit soil microbial activity. We investigated how nutrients limit bacterial and fungal biomass and community composition in organic and mineral soils within moist acidic tussock tundra ecosystems. We sampled two experimental arrays of moist acidic tussock tundra that included fertilized and non-fertilized control plots. One array included plots that had been fertilized annually since 1989 and the other since 2006. Fertilization significantly altered overall bacterial community composition and reduced evenness, to a greater degree in organic than mineral soils, and in the 1989 compared to the 2006 site. The relative abundance of copiotrophic α-Proteobacteria and β-Proteobacteria was higher in fertilized than control soils, and oligotrophic Acidobacteria were less abundant in fertilized than control soils at the 1989 site. Fungal community composition was less sensitive to increased nutrient availability, and fungal responses to fertilization were not consistent between soil horizons and sites. We detected two ectomycorrhizal genera, Russula and Cortinarius spp., associated with shrubs. Their relative abundance was not affected by fertilization despite increased dominance of their host plants in the fertilized plots. Our results indicate that fertilization, which has been commonly used to simulate warming in Arctic tundra, has limited applicability for investigating fungal dynamics under warming.Item Open Access Carbon-degrading enzyme activities stimulated by increased nutrient availability in Arctic tundra soils(Colorado State University. Libraries, 2013-10) Koyama, Akihiro, author; Wallenstein, Matthw D., author; Simpson, Rodney T., author; Moore, John C., author; Public Library of Science, publisherClimate-induced warming of the Arctic tundra is expected to increase nutrient availability to soil microbes, which in turn may accelerate soil organic matter (SOM) decomposition. We increased nutrient availability via fertilization to investigate the microbial response via soil enzyme activities. Specifically, we measured potential activities of seven enzymes at four temperatures in three soil profiles (organic, organic/mineral interface, and mineral) from untreated native soils and from soils which had been fertilized with nitrogen (N) and phosphorus (P) since 1989 (23 years) and 2006 (six years). Fertilized plots within the 1989 site received annual additions of 10 g N⋅m-2⋅year-1 and 5 g P⋅m-2⋅year-1. Within the 2006 site, two fertilizer regimes were established - one in which plots received 5 g N⋅m-2⋅year-1 and 2.5 g P⋅m-2⋅year-1 and one in which plots received 10 g N⋅m-2⋅year-1 and 5 g P⋅m-2⋅year-1. The fertilization treatments increased activities of enzymes hydrolyzing carbon (C)-rich compounds but decreased phosphatase activities, especially in the organic soils. Activities of two enzymes that degrade N-rich compounds were not affected by the fertilization treatments. The fertilization treatments increased ratios of enzyme activities degrading C-rich compounds to those for N-rich compounds or phosphate, which could lead to changes in SOM chemistry over the long term and to losses of soil C. Accelerated SOM decomposition caused by increased nutrient availability could significantly offset predicted increased C fixation via stimulated net primary productivity in Arctic tundra ecosystems.Item Open Access Microbial responses to multi-factor climate change: effects on soil enzymes(Colorado State University. Libraries, 2013-06) Steinweg, J. Megan, author; Dukes, Jeffrey S., author; Paul, Eldor A., author; Wallenstein, Matthew D., author; Frontiers Research Foundation, publisherThe activities of extracellular enzymes, the proximate agents of decomposition in soils, are known to depend strongly on temperature, but less is known about how they respond to changes in precipitation patterns, and the interaction of these two components of climate change. Both enzyme production and turnover can be affected by changes in temperature and soil moisture, thus it is difficult to predict how enzyme pool size may respond to altered climate. Soils from the Boston-Area Climate Experiment (BACE), which is located in an old field (on abandoned farmland), were used to examine how climate variables affect enzyme activities and microbial biomass carbon (MBC) in different seasons and in soils exposed to a combination of three levels of precipitation treatments (ambient, 150% of ambient during growing season, and 50% of ambient year-round) and four levels of warming treatments (unwarmed to ∼4° C above ambient) over the course of a year. Warming, precipitation and season had very little effect on potential enzyme activity. Most models assume that enzyme dynamics follow microbial biomass, because enzyme production should be directly controlled by the size and activity of microbial biomass. We observed differences among seasons and treatments in mass-specific potential enzyme activity, suggesting that this assumption is invalid. In June 2009, mass-specific potential enzyme activity, using chloroform fumigation-extraction MBC, increased with temperature, peaking under medium warming and then declining under the highest warming. This finding suggests that either enzyme production increased with temperature or turnover rates decreased. Increased maintenance costs associated with warming may have resulted in increased mass-specific enzyme activities due to increased nutrient demand. Our research suggests that allocation of resources to enzyme production could be affected by climate-induced changes in microbial efficiency and maintenance costs.