Life Sciences Commons^™

A Conservation Model: Costa Rican Conservation Strategies Effectively Preserve Their Threatened Primates, Ryan Belmont

Regis University Student Publications (comprehensive collection)

The wildlife of Costa Rica has experienced various anthropogenic threats over the last century including climate change and agricultural expansion. The mantled howler monkey (Alloutta palliata), Central American spider monkey (Ateles geoffroyi), white-faced capuchin (Cebus imitator), and the Central American squirrel monkey (Saimiri oerstedii) are Costa Rica’s native primates that face several anthropogenic threats such as deforestation for agriculture and climate change. In response to increased threats to its four native species of non-human primates, Costa Rica has implemented effective governmental conservation tactics such as the Payments for Environmental Services program, ecotourism …

Improving The Land Trust Model’S Impact On Environmental Conservation In Northern California, Peter Talbot

Master's Projects and Capstones

For years, the land trust sector of California and much of the United States has operated with a dollars and acres mentality that has prioritized fundraising as a result of acreage protected. Within California, nearly 5.8 million acres of land have been protected by 132 land trusts throughout the state. To accommodate for the diverse cross-section of land and the many needs of the population, land trusts take on numerous shapes and sizes. A unique aspect of this diversity is the rich agricultural and natural spaces found throughout the state. This mix of land and variety of land uses has …

Illuminating The Drivers Of Genomic Diversification In Lamprologine Cichlids Of The Lower Congo River, Naoko P. Kurata

Dissertations, Theses, and Capstone Projects

Freshwater fishes are extraordinarily diverse, considering their available habitats represent a tiny proportion of the earth’s surface. Rivers connect heterogeneous habitats in a linear form and provide excellent simplified models to understand how aquatic biodiversity evolves. In particular, the lower Congo River (LCR) in west Central Africa consists of a dynamic hydroscape exhibiting extraordinary aquatic biodiversity, endemicity, and morphological and ecological specialization. This system is thus an excellent natural laboratory for understanding complex speciation and population diversification processes. In my research, I explore various drivers of diversification, and adaptive evolution in rheophilic lamprologine cichlids endemic to the LCR, including Lamprologus …

Pasturelands As Natural Climate Solutions: A Socioecological Study Of Tree Carbon And Beef Production Trade-Offs, Bela Starinchak

Masters Theses, 2020-current

Forest restoration is the most effective natural climate solution, with the potential to sequester 37% of the carbon dioxide (CO₂) needed to reach the Paris climate mitigation goal. Cattle pastures offer an underutilized opportunity to increase global forest restoration efforts, improve biodiversity, and maximize carbon storage through the adoption of management strategies that prioritize the incorporation of trees into pasturelands. However, remote estimations of tree carbon storage in pastoral systems have never been field-verified and their accuracy is unclear. Furthermore, the effect of increased trees on cattle production is understudied across biomes. Lastly, the restoration potential of these …

Effects Of Climate Change And Landscape-Scale Forest Management On Avian Communities, Abundance, And Nest Success In The Appalachian Mountains, Hannah L. Clipp

Graduate Theses, Dissertations, and Problem Reports

Birds are integral components of ecosystems and account for billions of dollars in tangible benefits to humans. As such, recent continental declines of bird species have ecological and economic consequences, providing the impetus for my dissertation research. I identified knowledge gaps and proposed novel questions about how birds in the Appalachian Mountains are influenced by changing environmental conditions due to climate change and forest management. The Appalachian Mountains encompass an important biogeographical region with high conservation value due to its myriad habitats and corresponding bird species diversity. Thus, there is a critical need to evaluate the effects of shifting climate …

Evaluating Current And Future Potential Distribution Of Epiphytic Orchids In The Congo Basin With Ecological Niche Models, Michael L. Ngoh

Masters Theses

The Congo Basin Forest harbors a rich diversity of epiphytic communities, with the Orchidaceae alone making up more than 50% of all epiphytes in the region. Despite the huge diversity of epiphytes, many species, including epiphytic orchids, are at risk to a diverse array of threats. Climate change for instance poses severe threats to epiphytic orchids due to elevated temperatures, prolonged periods of droughts, as well as reduced rainfall across the Congo Basin Forest. In this study, we used ecological niche modeling and GIS techniques to identify spatial patterns of species richness, potential future climate refugia, and novel climatic suitability …

From Individuals To Communities: The Effect Of Climate Change On Ectothermic Predators, Matthew Lawrence Meehan

Electronic Thesis and Dissertation Repository

The living components of ecological systems exist within a nested hierarchy, consisting of individuals, populations, and communities. Because of this nestedness, climate change can greatly impact ecological systems, as whole-organism metabolic and physiological demands change for ectotherms under warming, the effects of which may compound with every succeeding level. Therefore, a multi-level approach can better isolate how climate change will reshape ecological systems. In my doctoral research, I used feeding and mesocosm experiments to examine how climate change affects ectothermic predators at the individual-, population-, and community-level, using mesostigmatic mites (Arachnida: Parasitiformes) as my model predator. My research objectives were …

A Tipping Point In The Ecuadorian Amazon Rainforest: Current And Future Land-Use And Climate Change Trends, Alula Shields

Masters Theses

Many regions of the Amazon are experiencing drastic changes as deforestation and climate change drive the world’s largest continuous rainforest towards a ‘tipping point’. These disturbances are changing natural cycles that once past a critical threshold, will mark an unstoppable transition to an altered ecosystem. Losing areas of the Amazon rainforest will have implications for the global climate, global carbon budget, and global hydrological regimes. Scholars have projected these tipping points for areas of the eastern Amazon rainforest, but much less scholarship focuses on the headwaters of the Western Amazon, an area of great cultural and biological importance. Ecuador is …

Diversity And Drivers Of Oribatid Mites (Acari: Oribatida) In Boreal Peatlands, Carlos Rafael De Araujo Barreto

Electronic Thesis and Dissertation Repository

Boreal peatlands are important ecosystems for carbon cycling, storing 1/3 of the world’s terrestrial carbon in only ~3% of the globe, making them a key component of potential mitigation strategies in response to global climate warming. Experiments have shown that warming can affect plant and microbial communities in ways that potentially shift peatlands from carbon sinks to sources. Soil food webs, including the microarthropod community, are key in carbon cycling but are relatively understudied both in peatlands and under experimental warming. My research capitalized on a large-scale experimental field manipulation of warming in two contrasting peatland sites in Northern Ontario, …

The Potential Influence Of Abiotic Conditions On Mussel Species Abundance In San Francisco Bay, Alexandra G. Farrell, M. Christina Vasquez Dr.

Honors Thesis

Climate change has negatively altered seawater conditions, which may have severe implications for marine ecosystems. Mussels are susceptible to environmental changes since they are primary consumers and filter-feeding bivalves. Two species of particular interest to the West Coast of the U.S. are Mytilus galloprovincialis and M. trossulus. M. trossulus is native to the California Coast and was historically prevalent from Southern California to Washington. However, with increased shipping and rising seawater temperature, M. galloprovincialis, an invasive species from the Mediterranean, pushed the species range of M. trossulus poleward. M. trossulus is more tolerant of cold seawater with variable salinity while …

Climate-Driven Impacts On Himalayan Aquatic Biodiversity: A Case Study Involving Snowtrout (Cyprinidae: Schizothorax), Riri Wiyanti Retnaningtyas

Graduate Theses and Dissertations

Monitoring biodiversity, to include its relative dispersal and contraction, has become a conservation task of great importance, particularly given the catastrophic and ongoing loss of habitat due to climate change. However, the timing, direction, and magnitude of these rates vary across taxa and ecosystems. Predicting specific impacts of climate change can thus be difficult and this, in turn, hampers management action. Metrics are needed to not only quantify contemporary requirements of species, but also predict potential distributions that fluctuate in lockstep with climate.

Montane ecosystems in the Himalayas are highly impacted by climate change, yet remain largely understudied due to …

Drivers Of Decadal Vegetation Change In Northern Alaska, Jacob Allen Harris

Masters Theses

The Arctic is experiencing rapid climate change. This research documents vegetation change near Atqasuk and Utqiaġvik, Alaska. At each location, 30 plots distributed in a matrix across the landscape, were sampled annually from 2010 to 2019 using a point frame. For every encounter we recorded the height and classified it into eight broad functional groups (deciduous shrubs, evergreen shrubs, forbs, graminoids, bryophytes, lichens, litter and standing dead vegetation); for vascular plants we also identified the species. We found a consistent increase in plant stature and cover over time which was dramatic at Atqasuk. Graminoid cover and height increased at both …

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 …

Interacting Effects Of Climate And Biotic Factors On Mesocarnivore Distribution And Snowshoe Hare Demography Along The Boreal-Temperate Ecotone, Alexej P. Siren

Doctoral Dissertations

The motivation of my dissertation research was to understand the influence of climate and biotic factors on range limits with a focus on winter-adapted species, including the Canada lynx (Lynx canadensis), American marten (Martes americana), and snowshoe hare (Lepus americanus). I investigated range dynamics along the boreal-temperate ecotone of the northeastern US. Through an integrative literature review, I developed a theoretical framework building from existing thinking on range limits and ecological theory. I used this theory for my second chapter to evaluate direct and indirect causes of carnivore range limits in the northeastern US, …

A Comparison Of Fuel Reduction Methods For Wildfire Risk Management And Climate Change Resiliency In Mixed Conifer Forests In The Sierra Nevada, Heather Navle

Master's Projects and Capstones

Wildfires in the mixed conifer forests of California’s Sierra Nevada have been a common and natural disturbance for thousands of years, historically occurring every 3 to 30 years. The flora and fauna of the mixed conifer forest have evolved to depend on low to moderate severity wildfires for reproduction, foraging, and habitat. However, the Sierra Nevada has experienced dramatic environmental changes over the past ~150 years as a result of three main factors: wildfire suppression, climate change, and habitat loss. Because of the threat wildfires pose to human lives, property and timber harvest, they have been suppressed to an extent …

Composition And Ecology Of Avian Communities Along Elevational Gradients In Borneo, Ryan Christian Burner

LSU Doctoral Dissertations

A primary goal of ecology is to explain the diversity and distribution of organisms. Species distributions can be a function of abiotic factors, species interactions, dispersal limitations, and history, but the relative importance of these factors is widely debated. Elevational gradients are useful systems for studying these effects because many of these factors vary predictably with elevation, and because elevational gradients are replicated many times across the earth. However, few quantitative surveys of Southeast Asian bird communities have been conducted along elevational gradients. In this study, I surveyed birds using point counts and measured habitat and temperature across primary forest …

Shade Trees Preserve Avian Insectivore Biodiversity On Coffee Farms In A Warming Climate, Sarah L. Schooler

Cal Poly Humboldt theses and projects

Coffee is an important export in many developing countries, with a global annual trade value of $100 billion. Climate change is projected to drastically reduce the area where coffee is able to be grown. Shade trees may mitigate the effects of climate change through temperature regulation for coffee growth, temperature regulation for pest control, and increase in pest-eating bird diversity. The impact of shade on bird diversity and microclimate on coffee farms has been studied extensively in the Neotropics, but there is a dearth of research in the Paleotropics. I examined the local effects of shade on bird presence and …

Understanding The Impacts Of Current And Future Environmental Variation On Central African Amphibian Biodiversity, Courtney A. Miller

University of New Orleans Theses and Dissertations

Global climate change is projected to impact multiple levels of biodiversity by imposing strong selection pressures on existing populations, triggering shifts in species distributions, and reorganizing entire communities. The Lower Guineo-Congolian region in central Africa, a reservoir for amphibian diversity, is predicted to be severely affected by future climate change through rising temperatures and greater variability in rainfall. Geospatial modelling can be used to assess how environmental variation shapes patterns of biological variation – from the genomic to the community level – and use these associations to predict patterns of biological change across space and time. The overall goal of …

A Comparison Of Benthic Macroinvertebrate Assemblages Between Perennial And Intermittent Headwater Streams Of The Mattole River In Northern California, Usa, Mason S. London

Cal Poly Humboldt theses and projects

Intermittent streams are common throughout the world and comprise 60% or more of total river lengths in the conterminous United States. Despite their prevalence, intermittent streams are understudied, particularly first-order headwater streams, which are vital for maintaining the function, health and biotic diversity of river networks. In June 2016, I sampled five intermittent and five perennial headwater streams in the Mattole River watershed in northwestern coastal California, USA, to compare benthic macroinvertebrate (BMI) assemblages between intermittent and perennial streams. BMI samples were collected using a 500µm mesh D-net at eight randomly located riffles along a 150-m reach, and then composited, …

The Impacts Of Climate Change On Communities Of Fungi In Boreal Peatlands, Asma Asemaninejad Hassankiadeh

Electronic Thesis and Dissertation Repository

Peatlands have an important role in global climate change through sequestration of atmospheric CO₂. Climate change is already affecting these ecosystems, including both above- and below- ground communities and their functions. Fungi play a central role in these communities. As a result, there is concern that altered fungal community function may turn peatlands from carbon sinks to carbon sources, greatly exacerbating the impacts of climate change. In order to gain a better insight into effects of climate change on the structure and function of these carbon sequestrating ecosystems, this thesis focuses on diversity and structure of fungal communities …

Integrated Modeling Of Land Use And Climate Change Impacts On Multiscale Ecosystems Of Central African Watersheds, Simon Nampindo

Doctoral Dissertations

Assessment and management of ecosystem services demands diverse knowledge of the system components. Land use change occurring mainly through deforestation, expansion of agriculture and unregulated extraction of natural resources are the greatest challenges of the Congo basin and yet is central to supporting over 100 million people. This study undertook to implement an integrated modeling of multiscale ecosystems of central African watersheds and model the impact of anthropogenic factors on elephant population in Greater Virunga landscape. The study was conducted at varied scales, regional, landscape, and community. Regional study included watershed analysis and hydrological assessment using remotely sensed data implemented …

Ant Community Dynamics And The Effects Of Global Warming, Katharine Lisa Stuble

Doctoral Dissertations

This dissertation seeks to provide an understanding of how species coexist and, further, how climate change may alter communities by acting on the mechanisms that promote coexistence. Specifically, I examined coexistence among ant species in eastern deciduous forests and the effects that warming may have on foraging activity. Through a series of field observations, I sought evidence for the importance of four of the most commonly cited mechanisms for coexistence among ant species: the dominance – discovery tradeoff, the dominance – thermal tolerance tradeoff, spatial segregation, and niche partitioning. In this system, I did not find evidence for any of …

Swamp : Walking The Wetlands Of The Swan Coastal Plain ; And With The Exegesis, A Walk In The Anthropocene: Homesickness And The Walker-Writer, Anandashila Saraswati

Theses: Doctorates and Masters

This project is comprised of a creative work and accompanying exegesis. The creative work is a collection of poetry which examines the history and ecology of the wetlands and river systems of the Swan Coastal Plain, and which utilises the practice of walking as a research methodology. For the creative practitioner walking reintroduces the body as a fundamental definer of experience, placing the investigation centrally in the corporeal self, using the physical senses as investigative tools of enquiry. As Rebecca Solnit comments in her history of walking, ‘exploring the world is one of the best ways of exploring the mind, …