Plant Biology Commons^™

Adapting Population Genetics, Practice, And Policy For Plant Conservation In A Changing World, Cooper M. Kimball-Rhines

Graduate Doctoral Dissertations

Biodiversity conservation is an inherently interdisciplinary goal that requires effective collaboration among academics, ecosystem managers, policymakers, and other stakeholders. Codesigning research with these groups ensures experiments are useful and improves adoption of policy and practice recommendations while advancing our understanding of basic science. This dissertation explores the power of codesigned research in shaping plant conservation strategies using stakeholder engagement, causal inference, demographic modeling, and multi-omic sequencing techniques. In chapter 1 I discuss the history of New England ecosystems and the need for research-driven changes to plant conservation policy and practice in the face of global change. In chapter 2, I …

Evaluating The Impact Of Intercropping Vegetables And Cut Flowers On Yield And Conservation Biological Control, Alliance Igiraneza

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Specialty crops such as vegetables are some of the most susceptible to yield losses and increased management difficulty over time due to pests. One of the potential solutions to this problem, which aims at ensuring the sustainability of the sector, is using conservation biological control practices such as intercropping to increase diversity, while maintaining the economic feasibility and profitability of the system. This study was conducted to evaluate the impact of this management practice using Bell pepper (Capsicum annuum var. King Arthur) as the main crop, intercropped with flowers including zinnia (Zinnia elegans var. Benary’s Giant), sunflower ( …

The Highs And Lows Of Life In A Valley: Topographic Controls On Tundra Vegetation In A Warming Arctic, Ruth S. Dunlap

Biology Honors Projects

Topographic heterogeneity structures Arctic plant communities, impacting broader ecosystem responses to climate change. The role of topography in shaping leaf physiological, nutritional, and structural traits in the Arctic is important, yet not well characterized across diverse tundra landscapes. To address these controls, we examined plant community composition and measured leaf traits in a few representative species along a heath-slope-valley gradient in Varanger, Norway. Our results indicated that valleys are more biodiverse, driven by forb and graminoid dominance, whereas slopes and heaths had less diversity with high shrub abundance. Leaf physiology and structural traits did not vary across topographic positions, though …

Testing The Intermediate Disturbance Hypothesis On Anthropogenic Pressure In Central Alabama, Gavin Terrell

Theses

Biodiversity is fundamental to maintaining ecosystem structure and function globally. Prior to the late 20th century, ecological theory generally predicted that biodiversity would be highest in systems experiencing minimal disturbance. However, Joseph H. Connell challenged this view with the Intermediate Disturbance Hypothesis (IDH), which posits that species diversity peaks at intermediate levels of disturbance and declines under conditions of both low and high disturbance. Although widely cited, the applicability of the IDH to natural systems remains debated, particularly in the context of anthropogenic disturbances and when diversity is measured beyond species richness alone.

This study evaluated the predictions of the …

Integrated Gamebird Farming As An Incentive To Promote Biodiversity And Conservation Of Rangelands, P J. Wiljoen, C R. Hurt

IGC Proceedings (1977-2023)

The popularity of gamebird hunting as a sport in Southern Africa serves as an incentive to rangeland owners to increase biodiversity on their properties. Gamebird utilisation is compatible with virtually all forms of land use, be it crop, domestic stock or wildlife production or a combination thereof, The range in habitat requirements, behaviour patterns and feeding niches of indigenous gameblrds ensures that at least one species is compatible with a specific agricultural practice, climate or vegetation type. Marginal and wasteland areas such as marsl}es, gullies, road verges and rocky outcrops, are prime gamebird production areas. The prospects of sport and …

Conservation Of Biodiveristy In Managed Rangelands, With Special Emphasis On The Ecological Effects Of Large Grazing Ungulates, Domestic And Wild, Patrick Duncan, Peter J. Jarman

IGC Proceedings (1977-2023)

Biodiversily with its different components (genes, species and ecosystems) is defined in relation to rangelands, whose Importance in its conservation is described. At the fine scale grasslands are much more diverse than tropical rain forest, and are comparably diverse at a regional scale, at least in Africa. Rangelands are crucially important world wide for 1he conservation of plants, and also for birds and large mammalian herbivores. Large ungulates (and other large herbivores) ace "keystone" species in these·ecosystems, playing a crucial role in the maintenance of diverse communities of plants, birds and invertebrates associated with such grasslands. Modification of the natural …

Spatial Analysis Of American Chestnut (Castanea Dentata) Distribution And Ecology In Kentucky’S Federal Lands, Jacob Raymond Pease

Murray State Theses and Dissertations

Anthropogenic factors have been the cause of the decline of tree species across the globe. From unsustainable logging and development to disease and improper management, threats to forests have taken their toll. The American chestnut (Castanea dentata) was once an integral basal tree species in Appalachian forests, but chestnut blight drove the species to functional extinction by the mid-1900s. The recent creation of genetically modified chestnuts gives hope for future restoration of the species throughout its historical range. Despite blight resistance, effective restoration will require optimal site selection for finding and planting chestnuts, which will maximize limited resources. …

Bioremediation In The Chesapeake Bay: Anthropogenic Ocean Acidification Mitigation In An Interactive Multi-Trophic Ecosystem, Cree Taylor

AUCTUS: The Journal of Undergraduate Research and Creative Scholarship

Zostera marina is a species of marine macrophyte that has been largely prioritized in past submerged aquatic vegetation (SAV) restoration initiatives within the Chesapeake Bay because of its 1) previous abundance, 2) demonstrated carbon burial abilities, and 3) observed ability for meadows of Z. marina to ameliorate low pH conditions. Due to the temperature variability and poor water quality in the Chesapeake Bay, Z. Marina beds have experienced several die-off events with limited capacity for regrowth. Ruppia maritima, an opportunistic species with tolerance to temperature shifts within the bay, may have the potential to maintain SAV coverage in areas …

Ocean Acidification Mitigation: Potential Expansion Of Sav Restoration Strategy In The Chesapeake Bay, Cree N. Taylor

Undergraduate Research Posters

Zostera marina is a species of marine macrophyte that has been largely prioritized in past submerged aquatic vegetation (SAV) restoration initiatives within the Chesapeake Bay because of its 1) previous abundance, 2) demonstrated carbon burial abilities, and 3) observed ability for meadows of Z. marina to ameliorate low pH conditions. Due to the temperature variability and poor water quality associated with anthropogenic disturbances in the Chesapeake Bay, Z. Marina beds have experienced several die-off events with limited capacity for regrowth. This systematic review explored the possible benefits of focusing future SAV recovery initiatives on ensuring a diverse variety of SAV …

Searching For New Germplasm For The Year 2000 And Beyond, Rainer Schultze-Kraft, Warren M. Williams, John M. Keoghan

IGC Proceedings (1977-2023)

The likely germplasm needs for the next decades are discussed with major emphasis on tropical pastures, although many of the considerations apply also to temperate grasslands. The largest, and internationally most relevant, tropical-germplasm collections are held by CSIRO, CIAT and ILCA. Gerznplasm of <600 grass and <1500 legume species is available (with 6000-7000 and 26000-28000 accessions, respectively), representing 100-120 grass and 150-200 legume genera. Temperate germplasm collections are more numerous and hold larger numbers of accessions; they are, however, even more narrowly focused on very few genera (mainly four legume and eight grass genera). The numbers of species represented in the germplasm collections are only a fraction of considerably higher figures suggested in the literature as wild species with forage potential. Further collections to increase this fraction and to safeguard germplasm from genetic erosion and loss of biodiversity are warranted. International co-operation is suggested. Future germplasm needs are seen, in the tropics, mainly for low-input production systems on marginal, degraded lands and for agropastoral systems, and, in the temperate zone, for sustainable grasslands systems. Because of their dual­purpose characteristics legumes are expected to play a key role. It is suggested that the present collections might not contain a sufficiently broad base of germplasm with the required characteristics for the aforementioned production systems. Collection gaps can be identified only through thorough analyses of important genera and regions, based on a solid body of information that still needs to be assembled. A series of research topics is suggested to assist in future collection strategies, germplasm management and evaluation, and to create the basis for future breeding projects. However, expensive and long-term breeding programmes with tropical and many temperate forages are not encouraged for the near future unless the respective species and its natural variability are well enough known. The same applies to genetic manipulation via biotechnology. Implications arising from molecular biology are that new techniques are now available to improve understanding of genetic diversity and taxonomic relationships, and that the potential genetic resource now spans animals, micro-organisms and plants other than the target species. This wider genepool is also endangered and its conservation will rely on in situ preservation of the diverse ecosystems of which it is composed. The need of international support, co-operation and co-ordination regarding germplasm collection, related research and communication is emphasised. The creation of an JBPGR-sponsored, permanent, international working group on forages is suggested.

Are We Ignoring Science In Our Quest For Simplicity In Range Management?, W A. Laycock

IGC Proceedings (1977-2023)

Accurate determination of range condition and trend is essential for proper range management. In the United States, the range condition model currently used is not based on up-to-date ecological knowledge. It assumes a single stable state (climax) and linear pathways. Multiple stable state models more accurately depict community dynamics but have not been widely accepted. U.S. Federal land management agencies are using surrogates, such as qualitative “instant trend” measures and substitution of utilization for measured condition and trend to guide management. Most of these short cuts are not based on science. Attacks on livestock grazing by environmentalists are based on …

Production V Conservation: A Policy Dilemma In The Tree Clearing Debate In Queensland, Australia, J C. Scanlan, E J. Turner

IGC Proceedings (1977-2023)

A process for developing policy for tree clearing that meets the competing goals of conservation and production has been followed. There were two levels at which policy was developed. An overall Statewide policy outlined general targets to meet commitments of the Queensland Government. Local guidelines were developed by a large number of groups containing representatives of government and interested conservation movement and industry representatives. The policy and the local guidelines are an important part of the process used to assess applications for permits to clear woody vegetation.

Principles Of Tree Management In The Grazing Lands Of Queensland, Australia, J C. Scanlan, E J. Turner

IGC Proceedings (1977-2023)

The key factors that influenced the appropriateness of clearing were identified for Queensland. The first stage was to identify endangered and vulnerable vegetation types, with final agreement being that clearing would not be undertaken in these regional ecosystem types. For other regional ecosystems, the degree of clearing that was appropriate was determined from the original and current extent of that ecosystem type, the sustainability of any development and any off-site effects of clearing. The maximum slope suitable for clearing, the width of riparian buffers and other corridors were also determined. These local guidelines for tree clearing became a central part …

Increasing Grassland Biodiversity Within The Environmentally Sensitive Areas Scheme In The U.K, S Peel

IGC Proceedings (1977-2023)

The ESA scheme is the main vehicle in the UK for increasing biodiversity on agricultural land. It is voluntary, and payments are made to compensate for reduced profitability when prescribed practices are followed. These include conversion of cropping land to grassland, zero fertiliser use and late cutting for hay. The scheme is supported by an R & D programme aimed particularly at practical problems arising from the need to reconcile environmental targets with the need to maintain viable and profitable livestock systems. The paper cites examples of this R & D, including choice of seeds mixtures, the role of soil …

Medicinal Plants As Indicators Of Grassland Biodiversity, G Nagy, I Vinczeffy, K Peto

IGC Proceedings (1977-2023)

A study has been made to identify the medicinal plants on the existing Hungarian grasslands. Sixty-three plants have been found to possess medicinal effects. Twenty-six, 15 and 22 species are for internal, internal or external and external use, respectively. This result reflects the low management intensity of grasslands in the country, as well as the species richness of semi-natural grasslands. It is suggested that the number of medical plants on the grassland, - in general - can also be used as an indicator of grassland biodiversity.

Graded Management Intensity Of Grassland System For Enhancing Biodiversity On A Species And Landscape Scale, E Meister, B Koch

IGC Proceedings (1977-2023)

The objective of our research is to maintain and enhance wildlife resources, landscape diversity and economic competitiveness of grassland-ruminant systems. This may be accomplished by a diversified, graded management intensity of pastures and meadows (Dietl,1990), resulting in a network of intensively and extensively used grassland and other semi-natural habitats. Botanical diversity is thus increased on both a habitat and landscape level. In intensively farmed regions it may be necessary to re-establish species-rich grassland types and adjust management intensity to the site conditions and species’ requirements.

Integrating Satellite Images And Species-Based Vegetation Maps To Manage Native Grasslands, M Hall-Beyer, Q.H. J. Gwyn

IGC Proceedings (1977-2023)

Satellite image mapping of grasslands is problematic when species diversity occurs at a sub-pixel scale. We propose a method, called melody classification, to map ground cover units that group several spectral classes (colours). Melodies are defined as the normalized expected frequencies of each class within the ground cover unit. Starting from an unsupervised classification, an image is created showing the probability of finding each spectral class in the vicinity of each pixel. Each pixel is classified by comparing the melody in its neighbourhood with that of each ground cover unit. Accuracies are greatly enhanced over those of supervised classification. Melody …

Development Of Natural Horse Pastures In Finland In The 1900s, H Jansson, K H. Jansson, A Olin, T Talikka, J Pykala

IGC Proceedings (1977-2023)

The purpose of the study was to assess the importance of natural pastures as a growing environment for horses and, at the same time, to evaluate the landscape value of such pastures. Another aim was to look at possible ways of conserving areas which have been in use as horse pastures for a long period of time as traditional biotopes belonging to the Finnish horse grazing culture, and to examine how their management and care could be improved.

Bird Friendly Beef: Exploring The Impacts Of Regenerative Forage Production, B. Rigley, J. Gilley, Aem Johnson

IGC Proceedings (1977-2023)

In the eastern US, managed hayfields and pasturelands represent a significant portion of remaining available grassland bird habitat, hosting several declining species including the eastern meadowlark (Sturnella magna) and the grasshopper sparrow (Ammodramus savannarum). However, these working landscapes have deteriorated in their ability to support grassland birds in recent decades due to more frequent and early hay cuttings and intensive grazing. Since the conservation of grassland birds is inextricably linked to agricultural systems, for conservation to be effective, land management must aim to benefit both producers and birds. Regenerative agriculture is an emerging approach that incorporates …

Diversity And Sustainability Of The Pek Savannas Of The Lao Pdr, V Phengvichith, J B. Hacker

IGC Proceedings (1977-2023)

The pek savannas of the Lao PDR occur in the southern half of the country and are relatively undeveloped. They are disjunct upland communities characterised by an understorey dominated by three species of Arundinaria, known locally as pek. The canopy varies from open forest to woodland. In relatively undisturbed communities, pek grows to c. 1.5 m tall, and is generally 99% pure, with tall growing grasses occurring infrequently. Higher levels of disturbance lead to invasion of shrub species and ingress of some lower-growing grasses and occasional legumes, some of which are palatable to livestock. Pek is palatable to livestock …

The Plants Database: Providing Basic Plant Information, J S. Peterson, J F. Henson, W Oaks, J T. Kartesz

IGC Proceedings (1977-2023)

The PLANTS database provides basic plant information to the United States Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS), its clients, cooperators, and the general public via the World Wide Web (Fig. 1). The foundation of PLANTS is a taxonomic backbone (checklist) of the vascular and nonvascular plants of North America (north of Mexico) and United States territories in the Caribbean and Pacific regions. Attribute data are appended to this backbone pertaining to distribution, vegetative specifications, nativity, federal and state status, crop data, growth form, growth parameters, species abstracts, and images.

Challenges And Opportunities For Revegetation In Areas Dominated By Invasive Annual Grasses, B. A. Mealor, J. A. Crose

IGC Proceedings (1977-2023)

Invasive annual grasses (IAG) are a primary ecological threat to sustainability and ecological integrity of rangelands in the western U.S. While availability of effective tools to control IAG is increasing, ensuring compatibility of control practices with other management practices, such as seeding desirable species, is a critical information need. We summarize a series of studies investigating influences of timing, seeding depth, species selection, and planting timing with various herbicides in sites dominated by invasive annual grasses.

Contribute To A Definition Of Extensive Grazing (Mediterranean), J. Potes, J. P. F. Almeida, C. Matos, A. Teixeira

IGC Proceedings (1977-2023)

The subject of this paper is a definition of Extensive Grazing from Extensive Systems of Animal Production in Mediterranean environments. The edaphoclimatic characterization is essential to understand the low level of primary productivity as a consequence of irregular precipitation over the year and its absence during the long, dry and hot summer. The powerless of soils justify the limited contribution of plants and make clear the necessary recovery of the soil and storage of water naturally (soil) or artificially (irrigation). Considering the IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services) definition of extensive grazing it has been used the …

Regenera+.Uy: Designing A Co-Innovation Process To Apply The Principles Of Regenerative Livestock Production, Oscar Blumetto, M. Bustamante, A. Castagna, D. Caresani, G. Ciappesoni, R. Baptista, I. De Barbieri

IGC Proceedings (1977-2023)

Consumers around the world are beginning to demand products whose production systems have environmental guarantees. Among them, those derived from regenerative agriculture have a growing demand in many markets. A comprehensive environmental assessment was carried out in 9 case studies of mixed livestock production farms (cattle and sheep) in Uruguay as a basis for the development of a system redesign process following the principles of regenerative agriculture. The results show that emission intensity was 16.0, 10.5, and 49.2 kg CO2 eq kg-1 of beef, sheep meat, and greasy wool, respectively. Also, a simulation exercise shows a significative reduction of emission …

Ecosystem Benefits Of Invasive Annual Grass Removal, S. L. Clark

IGC Proceedings (1977-2023)

Invasive winter annual grasses (IAGs) are altering rangeland ecosystems across millions of hectares in the western US. These winter annuals outcompete native plants for soil moisture and nutrients, leading to devastating impacts on ecosystem functions. The IAG seedbank is short-lived and often does not persist beyond 3 years. Past tools for IAG control have only provided short-term control or caused injury to the native plant community, making it difficult for researchers to assess the ecosystem benefits of IAG removal. A newer herbicide option, indaziflam, provides IAG control for three or more years. Indaziflam’s extended soil residual control and tolerance of …

Below Ground Benefits Of Cactus Opuntia Stricta Under Rangeland Conditions In Laikipia, Kenya, K. T. Oduor, Jose C. B. Dubeux, W. O. Owino, M. Ruiz-Moreno, L. M. D. Queiroz, I. L. Bretas

IGC Proceedings (1977-2023)

Cactus Opuntia stricta primarily invades arid and semi-arid lands (ASALs), which form more than 80% of Kenya’s landmass. The ability of the plant to tolerate poor soils and accumulate biomass under low precipitation has resulted in studies into its potential use by pastoral communities for biofuel and livestock feed. However, few studies have assessed the below-ground benefits associated with cactus under rangeland conditions. In this study, we evaluated the root contributions of the invasives cactus Opuntia stricta under rangeland conditions in Laikipia, Kenya. The experiment was laid out in a randomized complete block design with ten (10) replicates, each measuring …

Integrating Plant Secondary Metabolites And Foraging Behavior To Enhance Animal Health In Ruminant Production Systems, J. J. Villalba, J. W. Macadam, S. Van Vliet, F. D. Provenza

IGC Proceedings (1977-2023)

Legumes and forbs contain bioactives or plant secondary compounds (PSC) with potential to enhance animal health through their antibiotic, antioxidant and immunomodulatory properties that are evident even at small dietary concentrations. In turn, ruminants can regulate their ingestion of PSC through behavioral mechanisms that allow for the efficient achievement of homeostasis. High concentrations of PSC lead to food avoidance, whereas lower content of PSC in the diet achieved through regulatory mechanisms of ingestion could promote medicinal and/or prophylactic effects in the animal and concomitant health benefits to milk and meat products. Under this context, we discuss the restructuring of rangelands …

Ruminant Agriculture: A Tool For Climate Change Mitigation, B. L. Peterson Munks, M. Rellaford, J. Shanahan, S. Urbanowitz, F. Wang, S. Wang, Y. Zhao, E. Bender

IGC Proceedings (1977-2023)

The quest to address and mitigate climate change has been dubbed a “wicked problem” as it involves many interconnected processes requiring a multifaceted, comprehensive approach. Animal agriculture contributes roughly 15% to CO2 equivalent (CO2e) emissions; as a result, a concerted effort is being made to develop and promote more climate-friendly production practices. These practices include species diversification in grasslands, improving grazing rotation, adding nitrogen amendments, and the use of feed additives to reduce enteric fermentation. Successful inter-seeding of legumes and deep-rooted native grasses increases soil organic carbon (SOC) pools in many systems by increasing the biological carbon inputs to the …

Biodiverse Forage Mixtures For Bees And Beef Cattle, J. O. C. Kubesch, S. P. Greiner, G. J. Pent, J. L. Reid, B. F. Tracey

IGC Proceedings (1977-2023)

Introduction: Beef cattle performance in the southeastern US is limited by tall fescue (TF) toxicosis. Native warm season grasses (NWSGs) can provide alternative forage for cattle and reduce TF toxicosis. Pollinator populations, especially bees, also have been declining across North America. Introducing native wildflowers into tall fescue grasslands might improve pollinator populations. An ongoing grazing experiment in central Virginia USA is testing the feasibility of integrating wildflowers and native grasses as a way to generate ecosystem services.

Objectives: This study sought to determine whether including native grasses and wildflowers in tall fescue pasture systems could improve beef heifer performance.

Methods: …

Adaptive Multi-Paddock Grazing Of Cover Crops In Integrated Crop-Livestock Systems In Mediterranean Regions: A Review, G. A. Musto, A. Swanepoel, J. A. Strauss

IGC Proceedings (1977-2023)

Small-grain farming systems in Mediterranean climatic regions are characterized by poor quality soils, high climate variability, and resulting heavy agrochemical reliance. The integration of continuously grazed monocrop pasture phases has improved soil fertility, crop productivity, and mitigated financial risk. However, emerging sustainability issues such as herbicide resistance, inputs costs rising disproportionately to product prices, and increasing climate variability and predictability, drive the need for ongoing innovation in crop-livestock integration. The option of growing multi-species cover crops as a dual-forage and service crop is evaluated within Mediterranean climate contexts. Furthermore, the option of subjecting the cover crops to adaptive multi-paddock (AMP) …