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Full-Text Articles in Life Sciences
Biodiversity And Global Change In Terrestrial Ecosystems, Timothy J. Ohlert
Biodiversity And Global Change In Terrestrial Ecosystems, Timothy J. Ohlert
Biology ETDs
Terrestrial ecosystems are critical to human and ecological processes but many gaps in our knowledge remain regarding how terrestrial plant communities assemble and respond to global change. I used field experiments distributed around the world, including long-term experiments from the Sevilleta National Wildlife Refuge (SNWR) in New Mexico and deserts of the southwestern U.S., to evaluate the consequences of drought and other abiotic stressors on plant communities. Dominant grasses were particularly important for the productivity and structure of grasslands at SNWR. In general, the structure of desert plant communities had high resistance to extreme drought, though grasses and other perennial …
Seed Bank Composition Within Two Sagebrush Communities: A Comparison Of Drought, Microsite, And Aboveground Community Effects, Allison Marie Nunes
Seed Bank Composition Within Two Sagebrush Communities: A Comparison Of Drought, Microsite, And Aboveground Community Effects, Allison Marie Nunes
Cal Poly Humboldt theses and projects
Soil seed banks are critical biodiversity repositories for many dryland plant communities. Understanding how environmental factors alter seed bank composition can provide valuable information on ecological processes within a community and be useful for creating land management strategies. Using the seedling emergence method, I characterized the seed bank of two adjacent dryland plant communities that vary in dominant sagebrush species, structure, and function. Specifically, within an Artemisia arbuscula dominated community and Artemisia cana dominated community, I assessed the influence of three environmental factors on each seed bank: experimentally imposed drought, shrub microsites (compared to interspaces), and aboveground vegetation. Within the …
Inoculum Potential Of Pinus Edulis-Associated Ectomycorrhizal Fungi Across A Forest Extirpation Chronosequence, Annie M. Montes
Inoculum Potential Of Pinus Edulis-Associated Ectomycorrhizal Fungi Across A Forest Extirpation Chronosequence, Annie M. Montes
Biology ETDs
Few studies have examined inoculum potential of ectomycorrhizal fungi (EMF) in the absence of plant hosts, yet persistence of these fungi may be paramount to resilience of Pinus edulis and other mycorrhizal plant species. We conducted a study in which seven sites were selected in northwestern New Mexico with known dates of P. edulis extirpation and a lack of regeneration. Age classes included: two sites extirpated 10-20 years ago, two extirpated 55-65 years ago, two extirpated 500+ years ago, and one extirpated 11,000+ years ago. At each site, two plots were paired: an extirpated plot and the nearest live adult …
Evaluating Current And Future Range Limits Of An Endangered, Keystone Rodent (Dipodomys Ingens), Ivy V. Widick
Evaluating Current And Future Range Limits Of An Endangered, Keystone Rodent (Dipodomys Ingens), Ivy V. Widick
Cal Poly Humboldt theses and projects
Climate is often considered the single most important factor limiting species’ ranges. Other factors, such as biotic interactions, are often assumed to be included via abiotic proxies. However, differential responses to climate change may decouple these relationships or lead to adaptation to novel environments. Accounting for competition and local adaptation should more accurately describe environmental factors influencing current distributions and increase the predictive accuracy of future distributions. Modeling the endangered giant kangaroo rat (Dipodomys ingens) is an excellent application of these model improvements, as the species range consists of geographically and genetically isolated populations experiencing disparate climatic change. …
Long-Term Changes In A Spatially Subsidized Insular Ecosystem In The Archipelago Of Bahía De Los Ángeles, Baja California, Mexico, Thais Fournier
Long-Term Changes In A Spatially Subsidized Insular Ecosystem In The Archipelago Of Bahía De Los Ángeles, Baja California, Mexico, Thais Fournier
Theses
Interactions between climate change and the processes that structure coastal communities are poorly understood.Long – term weather patterns that include extreme events (e.g., El Niño Southern Oscillation, or “ENSO”) allow us to test hypotheses of how changes in weather (e.g., precipitation) will influence communities over long time frames. One system that is particularly vulnerable to climate changes is the coastal ecotone, which occupies 8% of the earth’s surface. A large exchange of resources (spatial subsidies) link habitats across this ocean – land interface, often with dramatic consequences for the recipient systems. Spatial subsidies such as marine input influence …
Direct And Indirect Effects Of Climate Change On Plant Populations And Communities In Sagebrush Steppe, Andrew R. Kleinhesselink
Direct And Indirect Effects Of Climate Change On Plant Populations And Communities In Sagebrush Steppe, Andrew R. Kleinhesselink
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Rapid climate change presents humanity with a number of big problems. Foremost among these is the sad fact that the climate we will pass on to our children will likely be nothing like the climate that we inherited from our parents. Ecologists have collected solid evidence that climate change has already begun to affect the living things around us and the ecosystems humans depend on. Unfortunately, predicting the future effects of climate change on life on earth is not easy. We focused on three research goals as part of an effort to improve our ability to predict how plants and …
Assessing Growth Response To Climate Controls In A Great Basin Artemisia Tridentata Plant Community, Lorenzo F. Apodaca
Assessing Growth Response To Climate Controls In A Great Basin Artemisia Tridentata Plant Community, Lorenzo F. Apodaca
UNLV Theses, Dissertations, Professional Papers, and Capstones
An assessment of the growth response of key vegetative species to climatic variability is vital to identifying possible local impacts on ecosystems faced with imminent climate change. With current climate projections in Nevada predicting a shift to an even more arid climate with greater year-to-year variability, the imperative exists to identify the effects of specific climatic controls on plant growth and to research methods to assess large-scale vegetative changes, especially in more remote areas where readily available data sets may be lacking. This study utilized annual growth ring indices constructed from big sagebrush (Artemisia tridentatassp.tridentata) stems collected in Spring Valley, …
Bryoecology In The American Southwest: Patterns Of Biodiversity And Responses To Global Change, John Carroll Brinda
Bryoecology In The American Southwest: Patterns Of Biodiversity And Responses To Global Change, John Carroll Brinda
UNLV Theses, Dissertations, Professional Papers, and Capstones
This dissertation combines investigation of the large-scale responses of bryophyte species diversity and distribution with small-scale physiological adaptations to global change. These two areas of inquiry are linked because one way to predict plant species responses to global change is to examine their distribution across current ecological gradients produced by factors such as latitude and elevation. By examining these biogeographic patterns one can identify those species that have a narrow tolerance and therefore are most sensitive to change. Selected bryophytes might then be used as indicator species in long-term monitoring programs. Where historical data exist, these can be used to …