Life Sciences Commons^™

Is Climate Change Causing The Range Contraction Of Cape Rock-Jumpers (Chaetops Frenatus)?, Gregory D. Duckworth, Raquel A. Garcia, Rheinhardt Scholtz, Res Altwegg

Department of Agronomy and Horticulture: Faculty Publications

Species distribution models often suggest strong links between climate and species' distribution boundaries and project large distribution shifts in response to climate change. However, attributing distribution shifts to climate change requires more than correlative models. One idea is to examine correlates of the processes that cause distribution shifts, namely colonization and local extinction, by using dynamic occupancy models. The Cape Rock-jumper (Chaetops frenatus) has disappeared over most of its distribution where temperatures are the highest. We used dynamic occupancy models to analyse Cape Rock-jumper distribution with respect to climate (mean temperature and precipitation over the warmest annual quarter), …

Physiological And Transcriptomic Responses Of Two Artemisia Californica Populations To Drought: Implications For Restoring Drought-Resilient Native Communities, Hagop S. Atamian Dr., Jennifer L. Funk

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

As climate change brings drier and more variable rainfall patterns to many arid and semi-arid regions, land managers must re-assemble appropriate plant communities for these conditions. Transcriptome sequencing can elucidate the molecular mechanisms underlying plant responses to changing environmental conditions, potentially enhancing our ability to screen suitable genotypes and species for restoration. We examined physiological and morphological traits and transcriptome sequences of coastal and inland populations of California sagebrush (Artemisia californica), a critical shrub used to restore coastal sage scrub vegetation communities, grown under low and high rainfall environments. The populations are located approximately 36 km apart but …

Bison Movements Change With Weather: Implications For Their Continued Conservation In The Anthropocene, Nicholas A. Mcmillan, Samuel D. Fuhlendorf, Barney Luttbeg, Laura E. Goodman, Craig A. Davis, Brady W. Allred, Robert G. Hamilton

Department of Agronomy and Horticulture: Faculty Publications

Animal movement patterns are affected by complex interactions between biotic and abiotic landscape conditions, and these patterns are being altered by weather variability associated with a changing climate. Some animals, like the American plains bison (Bison bison L.; hereafter, plains bison), are considered keystone species, thus their response to weather variability may alter ecosystem structure and biodiversity patterns. Many movement studies of plains bison and other ungulates have focused on point-pattern analyses (e.g., resource-selection) that have provided information about where these animals move, but information about when or why these animals move is limited. For example, information surrounding the …

Climate Change And Management Impacts On Soybean N Fixation, Soil N Mineralization, N2O Emissions, And Seed Yield, Elvis F. Elli, Ignacio A. Ciampitti, Michael J. Castellano, Larry C. Purcell, Seth Naeve, Patricio Grassini, Nicolas C. La Menza, Luiz Moro Rosso, André F. De Borja Reis, Péter Kovács, Sotirios V. Archontoulis

Department of Agronomy and Horticulture: Faculty Publications

Limited knowledge about how nitrogen (N) dynamics are affected by climate change, weather variability, and crop management is a major barrier to improving the productivity and environmental performance of soybean-based cropping systems. To fill this knowledge gap, we created a systems understanding of agroecosystem N dynamics and quantified the impact of controllable (management) and uncontrollable (weather, climate) factors on N fluxes and soybean yields. We performed a simulation experiment across 10 soybean production environments in the United States using the Agricultural Production Systems sIMulator (APSIM) model and future climate projections from five global circulation models. Climate change (2020–2080) increased N …

The Last Continuous Grasslands On Earth: Identification And Conservation Importance, Rheinhardt Scholtz, Dirac L. Twidwell Jr

Department of Agronomy and Horticulture: Faculty Publications

Grasslands are the most threatened and least protected biome. Yet, no study has been conducted to identify the last remaining continuous grasslands on Earth. Here, we used World Wildlife Fund (WWF) and International Union for Conservation of Nature (IUCN) classifications to measure the degree of intactness remaining for the world's grassland ecoregions. This analysis revealed three findings of critical conservation importance. First, only a few large, intact grasslands remain. Second, every continent with a grassland ecoregion considered in this study contains at least one relatively intact grassland ecoregion. Third, the largest remaining continuous grasslands identified in this analysis have persisted …

Patterns And Potential Causes Of Changing Winter Bird Distributions In South Dakota, David L. Swanson, Reza Goljani Amirkhiz, Mark D. Dixon

The Prairie Naturalist

Average winter temperatures in the north-central United States have been increasing since the 1970s, and this warming might influence winter distributions of birds in the region. Species potentially influenced by such winter warming include short-distance migrants for which the northern boundary of the winter range is influenced by temperature, such as hermit thrush (Catharus guttatus), yellow-rumped warbler (Setophaga coronata), and fox sparrow (Passerella iliaca). We examined winter records during 1974–2017 from a citizen-science bird observation database for South Dakota to determine recent trends in winter records for these three species. We compared their occurrence patterns with those for three benchmark …

Solar Dimming Decreased Maize Yield Potential On The North China Plain, Qingfeng Meng, Baohua Liu, Haishun Yang, Xinping Chen

Department of Agronomy and Horticulture: Faculty Publications

Solar dimming has been increasing in rapidly developing regions (China and India) and threatening food security. Although previous studies have summarized the ef- fects of climate change-associated increases in temperature on agriculture, few have examined the effects due to solar dimming. Here, we analyzed the effects of solar dimming on maize on the North China Plain (NCP). It is reported that solar dimming intensified and maize yield potential decreased since the 1960s. The total decrease in solar radiation for the whole maize growing season of this period was 17%, and solar dimming explained 87% of the decrease in yield potential. …

Watching Grass Grow: How Soil Moisture Affects Vesicular-Arbuscular Mycorrhizae And Growth In Little Bluestem, Laura M. Jones

Honors Scholar Theses

Vesicular-arbuscular mycorrhizae (VAM) are an ancient mutualism in which soil-dwelling fungi enhance plant absorption of phosphorus and nitrogen in exchange for photosynthates. VAM are sensitive to changes in soil moisture and nutrient content, fluctuating between mutualism and parasitism depending on conditions of drought stress and nutrient deficiency. Understanding how VAM respond to precipitation changes is crucial for both conservation and agricultural purposes. To test how soil moisture changes the effects of VAM colonization and growth in little bluestem (Schizachyrium scoparium), a common prairie grass, I planted 300 seeds in a greenhouse in sterilized soil and soil inoculated with …

Diffuse Light And Wetting Differentially Affect Tropical Tree Leaf Photosynthesis, Z. Carter Berry, Gregory R. Goldsmith

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

‐Most ecosystems experience frequent cloud cover resulting in light that is predominantly diffuse rather than direct. Moreover, these cloudy conditions are often accompanied by rain that results in wet leaf surfaces. Despite this, our understanding of photosynthesis is built upon measurements made on dry leaves experiencing direct light.

‐Using a modified gas exchange setup, we measured the effects of diffuse light and leaf wetting on photosynthesis in canopy species from a tropical montane cloud forest.

‐We demonstrate significant variation in species‐level response to light quality independent of light intensity. Some species demonstrated 100% higher rates of photosynthesis in diffuse light …

Long-Term Sandhills Prairie Responses To Precipitation, Temperature, And Cattle Stocking Rate, John A. Guretzky, Cheryl Dunn, Heidi L. Hillhouse

Department of Agronomy and Horticulture: Faculty Publications

Understanding of Sandhills prairie, the most expansive sand dune region stabilized by perennial grasses in the Western Hemisphere, is limited by lack of long-term vegetation data. We used a 26-year dataset to evaluate Sandhills prairie responses to yearto- year variation in precipitation, temperature, and cattle stocking rate. Basal cover, a measurement that is constant seasonally and used to detect long-term changes in bunchgrass vegetation, was measured in 38–40 permanent plots positioned along four transects spanning 769 ha from 1979 to 2007. Across this period, total basal cover averaged 2.4 % and was dominated by warm-season grasses (81.1 %). Schizachyrium scoparium …

Simulating Long-Term Impacts Of Cover Crops And Climate Change On Crop Production And Environmental Outcomes In The Midwestern United States, Andrea D. Basche, Sotririos V. Archontoulis, Thomas C. Kaspar, Dan B. Jaynes, Timothy B. Parkin, Fernando E. Miguez

Department of Agronomy and Horticulture: Faculty Publications

It is critical to evaluate conservation practices that protect soil and water resources from climate change in the Midwestern United States, a region that produces one-quarter of the world’s soybeans and one-third of the world’s maize. An over-winter cover crop in a maize–soybean rotation offers multiple potential benefits that can reduce the impacts of higher temperatures and more variable rainfall; some of the anticipated changes for the Midwest. In this experiment we used the Agricultural Production Systems sIMulator (APSIM) to understand how winter rye cover crops impact crop production and environmental outcomes, given future climate change. We first tested APSIM …

Limited Alpine Climatic Warming And Modeled Phenology Advancement For Three Alpine Species In The Northeast United States, Michael L. Davis, Kenneth D. Kimball, Douglas M. Weihrauch, Georgia L. D. Murray, Kenneth Rancourt

Ecology Center Publications

• Premise of the study: Most alpine plants in the Northeast United States are perennial and flower early in the growing season, extending their limitedgrowing season. Concurrently, they risk the loss of reproductive efforts to late frosts. Quantifying long-term trends in northeastern alpine flower phenology and late-spring/early-summer frost risk is limited by a dearth of phenology and climate data, except for Mount Washington, New Hampshire (1916 m a.s.l.).
• Methods: Logistic phenology models for three northeastern US alpinespecies (Diapensia lapponica, Carex bigelowii and Vaccinium vitis-idaea) were developed from 4 yr (2008–2011) of phenology and air temperature measurements from 12 …

A History Of Place: Using Phytolith Analysis To Discern Holocene Vegetation Change On Sanak Island, Western Gulf Of Alaska, Cricket C. Wilbur

Antioch University Full-Text Dissertations & Theses

This study investigated a terrestrial climate proxy, phytoliths, as a complimentary approach to documenting the dynamics of present and past vegetation on Sanak Island, the largest island in a small island group in the eastern Aleutian archipelago, and as a new basis by which to interpret Holocene environmental variability in Alaska. A phytolith reference collection was established from 59 selected plant species of maritime tundra belonging to 27 families. The grass species and a sedge species produced abundant phytolith forms whereas the majority of dicotyledons in this study were trace producers of phytoliths. A paleoenvironmental reconstruction from fossil phytoliths recovered …