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Assessing Ecological Relationships Among Late Triassic Vertebrates In Petrified Forest National Park, Alexandra Davis Apgar

Earth and Planetary Sciences ETDs

The complex vertebrate ecosystem of the Late Triassic has not yet been fully understood, largely due to oversimplification of hypothesized trophic hierarchies and limited preservation of direct evidence of faunal interaction. Paleocommunity reconstruction attempts can also fall victim to taphonomic biases, time-averaging inaccuracies, and non-analogue paleoecologies. Utilizing a combination of PAIRS analysis and NMDS ordination, we highlight vertebrate faunal relationships within the Adamanian and Revueltian faunachrons of Petrified Forest National Park, assess the likelihood that these patterns have ecological rather than preservational drivers, and examine how these potential interactions may have been impacted by the Adamanian-Revueltian turnover event. We are …

Ecological Impacts Of Invasive Crayfish In A Naïve Riparian System, Gregor L. Hamilton

Biology ETDs

Aquatic and riparian food webs are inextricably linked. In deserts, they provide critical energy subsidies to surrounding terrestrial food webs, but these vital subsidies are not guaranteed; streams in arid lands are especially sensitive to perturbations. In this dissertation, I investigated the role of an oft-cited threat to stream communities in the lower Colorado River basin: non-native crayfish. I contributed to methodologies in passive integrated transponder use and length-weight relationships in crayfish to aid future research. I leveraged stable isotope analysis of δ¹⁵N, δ¹³C, and δ²H to understand crayfish role in the food webs. …

Combining Isotopic And Genetic Analyses To Quantify Microbial Facilitation Of Recalcitrant Resource Use By Terrestrial And Aquatic Consumers, Alexi Christina Besser

Biology ETDs

Quantifying the flow of energy and nutrients through food webs is foundational to understanding the structure and function of ecosystems. Here, I utilize the stable carbon and nitrogen isotope analysis of individual amino acids to trace the movement of essential amino acids through terrestrial and freshwater food webs in New Mexico, USA. I first explore isotopic patterns among co-occurring terrestrial plants and aquatic algae. I then combine this molecular isotopic approach with 16S and 18S rRNA sequencing to demonstrate the importance of gut microbiota as sources of essential amino acids to wild mammalian hosts. Next, I explore the roles of …

Reconstructing Energy Flow Through Modern And Historical Marine Communities: Insights From Amino Acid Isotope Analysis, Emma A. Elliott Smith

Biology ETDs

The fundamental currency of life is energy. Organisms need energy to grow, to survive and to reproduce. Understanding the acquisition of energy by consumers is thus a foundational aspect of biological research. This is especially important in the modern era, as impacts of ongoing anthropogenic effects will be mediated or amplified through food webs. Here, I explore how isotopic analysis of individual amino acids – a technique new to ecological studies – can be used to trace energy flow through animal communities in modern and ancient time periods. In particular, I focus on kelp forest food webs, which are nearshore …

The Evolution Of Diet Breadth In Melissodes Bees (Apidae: Eucerini), Karen W. Wright

Biology ETDs

The relationship between phytophagous insects and their host plants has interested scientists since Darwinian times. Using modern phylogenetic inference, we are able to investigate these patterns using, not only the phylogenies of the insects, but the evolutionary relationships among the plants they feed on as well. The relationships between bees and the plants they pollinate were traditionally seen as mutualistic and were treated separately from the research investigating the antagonistic relationships between phytophagous insects and their host plants. However, recent phylogenetic studies have made great progress including bee-host relationships in with the larger body of work on phytophagous insects.

The …

The Ecology Of Acequias In The Mora Valley: Patterns, Processes And Place-Based Knowledge, Shannon M. Rupert

Biology ETDs

In northern New Mexico, early settlements were clustered for protection of the people and access to water for domestic and agricultural uses was critical to their success. Irrigation ditches, known as acequias, brought water to the people, and were central to community life. These earthen ditches of varying lengths were built between one hundred and several hundred years ago, and most are still operational today. They divert water away from natural streams and across the landscape, through a system of man-made channels, until the unused water is diverted back into natural watercourses. These lateral channels appear to function as extensions …

Twenty-Eight Years Of The Us-Lter Program: Experience, Results, And Research Questions, James R. Gosz, Robert B. Waide, John J. Magnuson

Long Term Ecological Research Network

The U.S. Long Term Ecological Research program (hereafter US-LTER) concentrates on ecological processes that play out at the time scales spanning decades to centuries. This focuses US-LTER research between the most common time scales for ecological studies (1-3 years; Tilman 1989; Figure 1) and the much longer temporal fact of disciplines such as paleoecology. The importance of the decade-to-century time scale is particularly evident in light of the rapid changes in ecological forcing functions that are occurring at a broad range of spatial scales (Millennium Ecosystem Assessment 2005, Intergovernmental Panel on Climate Change 2007). Long-term data sets from programs such …