Life Sciences Commons^™

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 …

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 …

Ecological And Morphological Response Of Rodents To Environmental Change Over The Late Quaternary, Catalina Tome

Biology ETDs

The rapid progression of modern climate change is already altering ecosystems worldwide. By employing the fossil record, we can investigate how animals responded to past climatic changes and biodiversity loss. The paleontological record of the late Quaternary (past ~22000 years) encompasses a period of considerable environmental change in North America. Rising temperatures and climatic fluctuations are coupled with the extinction of the majority of large bodied mammals on the landscape. The combination of climate and extinction events led to changes in vegetation and community structure which likely affected the resources available and interactions between the remaining mammals within communities. Here, …

Warming Up: Climate Change Related Shifts Of Mycorrhizal Fungal Communities In High Latitude Ecosystems, Megan Rae Devan

Biology ETDs

This dissertation examines how climate change affects mycorrhizal fungal communities in boreal and arctic ecosystems. In chapter one, I revealed that increases in fire severity and related increases in deciduous tree dominance result in greater Ascomycota relative abundance (RA) and subsequent declines in Basidiomycota RA. In chapter two I analyzed the effects of post-fire mycorrhizal fungal communites on host growth. There were trends at the fungal genus level that were largely reflected at the guild level across all hosts; however, there were some fungal genera that had the opposite effect on different host species. In chapter three, I found host …

Biogeographical Implications Of Climate Change For An Alpine Mammal, The American Pika, Marie Louise Westover

Biology ETDs

Anthropogenic climate change has already impacted a majority of species globally. The aim of this dissertation is to understand how climate and climate change influences animal ecology and evolution across space and time, using the American pika (Ochotona. princeps) as a model system. I investigate how pika body size, diet, and occupancy are influenced by different aspects of climate over space and time. Body size in O. princeps populations best correlates to precipitation and vegetation, rather than temperature. Our findings suggest that pika body size may be more related to vegetation and food availability than the direct effects …

Linking Climate Change And Mortality In Piñon-Juniper Woodlands, From Leaf To Ecosystem, Amanda I. Liebrecht

Biology ETDs

As global climate changes, the Southwestern US is predicted to experience more frequent and intense drought events. Extreme droughts can drive decreases in both physiological and ecosystem function, and can result in widespread tree mortality. Piñon-juniper (PJ) woodlands are a prevalent ecosystem in the region, co-dominated by two tree species, piñon (Pinus edulis) and juniper (Juniperus monosperma). Drought-induced piñon mortality has occurred over the past few decades, coinciding with outbreaks of a piñon-specific bark beetle. Piñon and juniper have different hydraulic strategies (isohydry and anisohydry, respectively) that should affect the way each species responds to drought. …

Impacts Of Long-Term Precipitation Manipulation On Hydraulic Architecture, Xylem Function, And Canopy Status In A Piñon-Juniper Woodland, Patrick J. Hudson

Biology ETDs

The Southwestern US is predicted to become hotter and drier, as global climate change forces increasing temperatures and variability in timing and size of precipitation inputs. Drought stress has become more frequent in recent decades, and resulted in massive forest mortality in piñon-juniper woodlands. During recent severe droughts (2000-2003, 2009-2012), piñon pine (Pinus edulis Englem.) suffered disproportionately high mortality compared to co-occurring one-seed juniper (Juniperus monosperma [Engelm.] Sarg.). A large-scale precipitation manipulation experiment was established in a piñon-juniper woodland in central New Mexico to test hypotheses regarding tree survival and mortality with respect to altered water regimes. Our …

The Indirect Effects Of Climate Variability On The Reproductive Dynamics And Productivity Of An Avian Predator In The Arid Southwest, Corrie C. Borgman

Biology ETDs

The deserts of the Southwestern United States are experiencing rapid warming and climate models predict declining winter precipitation. The combined effects of higher air temperatures and drought are a reduction in productivity, which may importantly impact reproduction in consumers. Here, we investigate the effects of warming and drought on the reproductive timing and output in loggerhead shrikes (Lanius ludovicianus) in central New Mexico from 2007 to 2012. We found increases in air temperature of 3°C during the breeding season (March—July) and highly variable winter and annual precipitation. With increasing spring temperatures, shrikes advanced nesting phenology by 20 days over 6 …

Establishment Of Larrea Tridentata At The Northern Edge Of The Modern Mojave Desert: Insights From Neotoma Paleomiddens, Clare Steinberg

Biology ETDs

Shifting climates affect the composition of biological communities. If environmental conditions change sufficiently, new species can invade, leading to large-scale community turnover. Understanding how and why such shifts occur is crucial in this era of anthropogenic global change. Paleontological studies provide a valuable long-term perspective of the dynamics of community turnover. Here, we examine changes in the plant community over the past 34 thousand years in what is now the northern Mojave Desert. This time period includes the last glacial maximum as well as numerous smaller climatic fluctuations in the Holocene and the end of the Pleistocene. We quantified plant …

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 …

Stream Organic Matter Budgets, J.R Webster, Judy L. Meyer

Long Term Ecological Research Network

This analysis of organic matter dynamics in streams has 3 objectives: 1) to explore the relationships between physical characteristics of streams and their watersheds (climate, geomorphology) and steam organic matter dynamics using data from a broad geographic area; 2) to compare steam organic matter dynamics in a diverse array of steams in order to suggest determinants of observed patterns; and 3) to reveal deficiencies in currently available data on organic matter dynamics in steams. Streams were included in this analysis not to represent the global diversity of stream types but because organic matter data were available. In the introductory chapter …

1995 Proposed Program Of Work For Lter, Long Term Ecological Network

Long Term Ecological Research Network

Version II of the Proposed Program of Work for LTER Network Office in 1995-1996.

1995 Lter Network News And Mosaic Brochure Project, Maya Isabel Lazzaro, Long Term Ecological Research

Long Term Ecological Research Network

LTER Network News from 1995.

LTER Network News began in 1987.

1994 Ieee Computer Society Press Reprint, James W. Brunt

Long Term Ecological Research Network

Effective management of ecological research data can insure the security and accessibility of data that cannot be collected again under the same conditions and plays a key role in every aspect of the research project from experimental design to publication. Commercial relational database management software, developed an adequate solution for long-term scientific data management. An archive file format provides the standard around which a data file management system is implemented. The system works within the parameters of existing components of the operating system software. Data filters and data engines are used to communicate data to and from applications. This paper …

Lter Correspondence & Letters, Jerry F. Franklin

Long Term Ecological Research Network

1st. Letter written by Jerry F. Franklin, chair of LTER Network, addressed to David Greenland of the department of Geography. Franklin extends an invitation to the upcoming Coordinating Committee meeting taking place from October 19-21.

2nd. Letter written by Jerry F. Franklin, chair of LTER Network, addressed to Joshua Greenberg of he College of Forest Resources. Franklin extends an invitation to the upcoming Coordinating Committee meeting taking place from October 19-21.

3rd. Letter written by Jerry F. Franklin, chair of LTER Network, he writes on the significant decisions taken place over the LTER/CC meeting held on April 22-24.

4th. Letter …

Agenda Lter/Coordinating Committee Meeting, April 22-24, 1994, Long Term Ecological Research

Long Term Ecological Research Network

The latest agenda update for the LTER April 1994 Coordinating Committee Meeting.