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Full-Text Articles in Life Sciences

Abiotic And Biotic Drivers Of Plant Range Shifts In The Alpine, Clifton Powell Bueno De Mesquita Jan 2019

Abiotic And Biotic Drivers Of Plant Range Shifts In The Alpine, Clifton Powell Bueno De Mesquita

Ecology & Evolutionary Biology Graduate Theses & Dissertations

Over the course of Earth’s biological history, organisms have many times had to shift their geographic distributions in order to track changing abiotic conditions suitable for their growth, survival, and reproduction. Now more than ever, in the new geologic epoch of the Anthropocene, organisms will have to rapidly shift their ranges to adapt to climate change and other anthropogenic disturbances. The rearrangement of organisms can be facilitated or inhibited by biotic interactions between organisms. Here I examine plant range shifts in an alpine ecosystem in response to climate warming and earlier snowmelt, as well as the role of biotic ...


Local Trampling Disturbance Effects On Alpine Plant Populations And Communities: Negative Implications For Climate Change Vulnerability, Nathalie Chardon, Sonja Wipf, Christian Rixen, Annabarbara Beilstein, Daniel F. Doak Jan 2018

Local Trampling Disturbance Effects On Alpine Plant Populations And Communities: Negative Implications For Climate Change Vulnerability, Nathalie Chardon, Sonja Wipf, Christian Rixen, Annabarbara Beilstein, Daniel F. Doak

University Libraries Open Access Fund Supported Publications

Global change is modifying species communities from local to landscape scales, with

alterations in the abiotic and biotic determinants of geographic range limits causing

species range shifts along both latitudinal and elevational gradients. An important

but often overlooked component of global change is the effect of anthropogenic

disturbance, and how it interacts with the effects of climate to affect both species

and communities, as well as interspecies interactions, such as facilitation and competition.

We examined the effects of frequent human trampling disturbances on alpine

plant communities in Switzerland, focusing on the elevational range of the widely

distributed cushion plant Silene ...


Climate Change And Wildfire: Implications For Forest Management In The Blue Mountains Of Eastern Oregon, Angela Elaine Boag Jan 2018

Climate Change And Wildfire: Implications For Forest Management In The Blue Mountains Of Eastern Oregon, Angela Elaine Boag

Environmental Studies Graduate Theses & Dissertations

Shifting climate and wildfire regimes are changing forest structure and function globally. In the western US, future forest structure will be determined by interactions between climate change and disturbance, including increasingly frequent large wildfires, as well as the forest management actions of landowners and managers. While research on the ecological impacts of these changes is rapidly expanding, there is limited focus on how forest vulnerability may vary across land ownerships, which may have varying capacities for climate-adaptive forest management. In this dissertation, I explored how coniferous forests in the Blue Mountains of eastern Oregon are vulnerable to climate and wildfire ...


The Effects Of Human Trampling Disturbance, Plant-Plant Interactions, And Climate On The Performance And Distribution Of The Alpine Cushion Plant Silene Acaulis, Nathalie Isabelle Chardon Jan 2018

The Effects Of Human Trampling Disturbance, Plant-Plant Interactions, And Climate On The Performance And Distribution Of The Alpine Cushion Plant Silene Acaulis, Nathalie Isabelle Chardon

Environmental Studies Graduate Theses & Dissertations

Delineating the abiotic and biotic processes that set species geographic distributions has been a central theme in ecological research for hundreds of years, yet we still do not understand many aspects of this broad question. Discerning what processes determine past and current range limits is particularly critical for predicting how species distributions will respond to climate change. In Chapters 2 and 3, I address how the interactions of climate, inter-species interactions such as competition, and human disturbances together influence range limits. I show that disturbance has positive effects on the alpine cushion plants Silene acaulis and Minuartia obtusiloba at the ...


Conservative And Acquisitive Species Differentially Respond To Warmer Temperatures In The Alpine Tundra, Katherine Wentz Jan 2017

Conservative And Acquisitive Species Differentially Respond To Warmer Temperatures In The Alpine Tundra, Katherine Wentz

Environmental Studies Graduate Theses & Dissertations

Mountainous ecosystems are expected to have longer, warmer and drier growing seasons in the future. In this thesis, I examine how climate change may differentially affect two plant community types in the alpine tundra: conservative plant species characteristic of the dry meadow and acquisitive plant species characteristic of the wet meadow. I develop and use a photosynthesis-stomatal conductance model to explore how abiotic conditions, i.e. air temperature and soil moisture, and leaf traits, e.g. the leaf nitrogen content and plant height, govern conservative and acquisitive species’ assimilation. The model is parameterized and validated with data obtained at the ...


Hygromorphic Scales For Use In Water From Morning Dew And Elementary Model Of Hydrogel Expansion Properties, Nate Margolis Jan 2017

Hygromorphic Scales For Use In Water From Morning Dew And Elementary Model Of Hydrogel Expansion Properties, Nate Margolis

Materials Science & Engineering Graduate Theses & Dissertations

Secure access to water is a growing problem in the world today. Millions of people do not have contact with fresh or clean water for drinking. Consuming dirty water leads to many illnesses and deaths every year. When water is scarce people are less likely to follow basic hygiene which also adds to the problem of sickness from water. Currently most of the population gets their water from run-off such as rivers, lakes and other fresh water bodies. Aquafers can also provide water, however, once they do not replenish themselves so once they are empty they will no longer provide ...


Factors Driving Flowering Phenology And Reproductive Success In Silene Acaulis And Implications For Response To Climate Change, Ellen Waddle Jan 2017

Factors Driving Flowering Phenology And Reproductive Success In Silene Acaulis And Implications For Response To Climate Change, Ellen Waddle

Undergraduate Honors Theses

Along with survival, successful reproduction is one of the key features of individual performance that is necessary for a species to survive, including in the face of environmental alterations. This study examined possible drivers of reproductive success in alpine cushion plant Silene acaulis, and the implications of reproductive patterns for long-term stability of populations in the face of climate change. First, I asked whether the timing of flowering in a long-lived alpine plant species influenced whether flowers successfully produced fruit, and whether that timing was correlated with the plant’s long-term seed production. I found that the timing of flowering ...


Vegetative Response To Long-Term Resource Manipulations In The Alpine Tundra, Evelyn Beaury Jan 2017

Vegetative Response To Long-Term Resource Manipulations In The Alpine Tundra, Evelyn Beaury

Undergraduate Honors Theses

Considering their sensitivity to change, alpine plant communities are useful systems in studying the indirect effects of anthropogenic activities on the environment. Climate change is increasing variability of temperature and precipitation, shifting wind patterns, and altering nutrient composition and cycling (especially deposition of nitrogen (N) and phosphorus (P)). Therefore, it is becoming increasingly important to understand how climate change impacts vegetation. This study continues efforts of a Long Term Ecological Research program in the Colorado Rocky Mountains by surveying plant community composition in response to nutrient additions (N and P) and changing moisture regimes mimicking potential climate shifts. In addition ...


Microtopoclimatic Effects On A Climate-Sensitive Habitat Specialist, The American Pika (Ochotona Princeps), Aidan Taylor Beers Jan 2016

Microtopoclimatic Effects On A Climate-Sensitive Habitat Specialist, The American Pika (Ochotona Princeps), Aidan Taylor Beers

Ecology & Evolutionary Biology Graduate Theses & Dissertations

There has been increasing acknowledgement that refugia at different scales facilitate the long-term survival of species and populations through climate oscillations. Species distributions and persistence are already affected by current climate change, and many taxa will become more spatially limited and less connected under further warming scenarios. Identifying likely microrefugia will improve our predictions of how species, communities, and ecosystems are likely to respond to climate change by providing a clearer understanding of likely demographic processes and connectivity. In this thesis, I considered suitable microhabitat in the face of current changing climates in the context of the persistence or development ...


Multi-Proxy Reconstructions Of Holocene Environmental Change And Catchment Biogeochemistry Using Algal Pigments And Stable Isotopes Preserved In Lake Sediment From Baffin Island And Iceland, Christopher Roth Florian Jan 2016

Multi-Proxy Reconstructions Of Holocene Environmental Change And Catchment Biogeochemistry Using Algal Pigments And Stable Isotopes Preserved In Lake Sediment From Baffin Island And Iceland, Christopher Roth Florian

Geological Sciences Graduate Theses & Dissertations

Lake sediments provide a continuous record of environmental change, integrating information about multiple biogeochemical processes occurring within the lake and catchment. Much of this is recorded by the chemical characteristics of sedimentary organic matter, which can be used as a proxy for past conditions. This dissertation examines Holocene lake sediment records from Baffin Island and Iceland, which, as a result of Arctic amplification feedbacks, are particularly sensitive to changes in climate. We integrated sedimentary algal pigments with more commonly used proxies such as stable isotopes, C:N ratio, and biogenic silica in order to derive a more complete understanding of ...


Re-Evaluating Climate As The Best Predictor Of Pika (Ochotona Princeps) Surface Activity, Maxwell C. Plichta Jan 2016

Re-Evaluating Climate As The Best Predictor Of Pika (Ochotona Princeps) Surface Activity, Maxwell C. Plichta

Undergraduate Honors Theses

Alpine and subalpine ecosystems are expected to experience a disproportionate amount of warming in the coming decades. Rising temperatures in these ecosystems threatens biodiversity and water resources globally. The American pika (Ochotona princeps) is a small mammal restricted to talus and rocky slopes often found above treeline. O. princeps has an acute sensitivity to high temperatures and utilizes microhabitats present in the talus to regulate body temperature. These attributes make pikas a bioindicator candidate for warming in the alpine. Monitoring and predicting pika persistence represents a potentially powerful tool to asses the current and future health of alpine ecosystems. Here ...


Climate And Management Controls On Forest Growth And Forest Carbon Balance In The Western United States, Katharine Cashman Kelsey Jan 2015

Climate And Management Controls On Forest Growth And Forest Carbon Balance In The Western United States, Katharine Cashman Kelsey

Environmental Studies Graduate Theses & Dissertations

Climate change is resulting in a number of rapid changes in forests worldwide. Forests comprise a critical component of the global carbon cycle, and therefore climate-induced changes in forest carbon balance have the potential to create a feedback within the global carbon cycle and affect future trajectories of climate change. In order to further understanding of climate-driven changes in forest carbon balance, I (1) develop a method to improve spatial estimates forest carbon stocks, (2) investigate the effect of climate change and forest management actions on forest recovery and carbon balance following disturbance, and (3) explore the relationship between climate ...


Impacts Of Climate And Distrubances On Vegetation Dynamics In Piñon-Juniper Woodlands, Miranda D. Redmond Jan 2015

Impacts Of Climate And Distrubances On Vegetation Dynamics In Piñon-Juniper Woodlands, Miranda D. Redmond

Ecology & Evolutionary Biology Graduate Theses & Dissertations

Global climate change and altered disturbance regimes have already and are predicted to continue to cause significant shifts in vegetation distribution. Regional warming has increased tree mortality rates over the past several decades through increasing water deficits and insect outbreaks, which have dramatically changed forest and woodland structure and altered water and energy fluxes and carbon stocks. For the first part of my dissertation, I use field surveys and historical data to examine how changes in climate and recent piñon pine (Pinus edulis) mortality events may affect tree regeneration dynamics in the widely distribution piñon-juniper (Juniperus osteosperma and J. monosperma ...


Conifer Regeneration After Wildfire In Low-Elevation Forests Of The Colorado Front Range: Implications Of A Warmer, Drier Climate, Monica T. Rother Jan 2015

Conifer Regeneration After Wildfire In Low-Elevation Forests Of The Colorado Front Range: Implications Of A Warmer, Drier Climate, Monica T. Rother

Geography Graduate Theses & Dissertations

In recent years, concern has grown among researchers, land managers, and the public regarding potential shifts in forest resiliency to disturbances such as wildfire under warming climate conditions. We examined conifer regeneration after fire in low-elevation, ponderosa pine (Pinus ponderosa) forests of the Colorado Front Range (CFR). Given preliminary observations of limited post-fire conifer establishment, we developed the general hypothesis that warming temperatures and associated drought are less suitable for post-fire conifer regeneration. We surveyed juvenile conifer densities in six recently burned areas of the CFR and found that juvenile ponderosa pine and Douglas-fir (Pseudotsuga menziesii) densities were typically lower ...


Behavioral Baselines And Modeling In A Changing Climate: Relating Temperature To The Summertime Behavior Of The American Pika (Ochotona Princeps) In The Southern Rocky Mountains Of Colorado, Meghan Wiebe Jan 2015

Behavioral Baselines And Modeling In A Changing Climate: Relating Temperature To The Summertime Behavior Of The American Pika (Ochotona Princeps) In The Southern Rocky Mountains Of Colorado, Meghan Wiebe

Undergraduate Honors Theses

Small mammals that make use of sub-surface microclimates may be able to adapt quickly to a warming climate by altering the level and timing of certain surface activities. For example, energy-intensive territorial defense or foraging activities might be shifted to cooler times of day. This hypothesis was explored using data on the American pika (Ochotona princeps), a small, diurnal lagomorph closely related to rabbits that uses rocky microhabitats for shedding heat between bouts of surface activity. Over three consecutive summers (mid-June to mid-August, 2012-2014), 94 observations (45 minutes each) were conducted involving N = 61 unique pikas, using a standardized protocol ...


Changes In Tree Swallow Phenology Due To Climate Change In Alaska, Rachel Irons Jan 2015

Changes In Tree Swallow Phenology Due To Climate Change In Alaska, Rachel Irons

Undergraduate Honors Theses

Ecological effects of climate change are beginning to be seen across the globe. In avian species, these effects often manifest in earlier breeding dates. Tree swallows in the temperate zones of North America advanced their laying date by nine days between 1959 and 1991. However tree swallows in more arctic regions, where climate change is occurring more rapidly, have not yet been studied. Additionally, two important climate variables, wind and precipitation, have been largely ignored in climate change studies to date. I used tree swallow nest records from Fairbanks, Alaska to examine how climate change is affecting these birds in ...


Characterizing Metrics And Outcomes Of Stress In A Climate-Sensitive Species, The American Pika, Jennifer Lee Wilkening Jan 2014

Characterizing Metrics And Outcomes Of Stress In A Climate-Sensitive Species, The American Pika, Jennifer Lee Wilkening

Ecology & Evolutionary Biology Graduate Theses & Dissertations

The American pika (Ochotona princeps) is considered a sentinel species for detecting ecological effects of climate change. Pikas are declining within a large portion of their range, but previous studies have focused only on local pika extirpation as a metric of change. This approach does not take into account the role of behavioral thermoregulation and the pika's use of microhabitats to ameliorate variations in climate. Without evidence of a direct climatic impact on pikas, studies correlating pika habitat occupancy with climate metrics provide relatively weak support for projecting effects of climate change on this species. This dissertation research focuses ...


Fine Scale Climatic And Soil Variability Effects On Plant Species Cover Along The Front Range Of Colorado, Usa, William Frank Preston Cumming Jan 2013

Fine Scale Climatic And Soil Variability Effects On Plant Species Cover Along The Front Range Of Colorado, Usa, William Frank Preston Cumming

Geography Graduate Theses & Dissertations

Fine scale studies are rarely performed to address landscape level responses to microclimatic variability. Is it the timing, distribution, and magnitude of soil temperature and moisture that affects what species emerge each season and, in turn, their resilience to fluctuations in microclimate. For this dissertation research, I evaluated the response of vegetation change to microclimatic variability within two communities over a three year period (2009-2012) utilizing 25 meter transects at two locations along the Front Range of Colorado near Boulder, CO and Golden, CO respectively. To assess microclimatic variability, spatial and temporal autocorrelation analyses were performed with soil temperature and ...