An examination of the effectiveness of seeding, burning, and mowing in the reestablishment of tallgrass prairie species on overgrazed and abandoned pastureland. The study site is a 20 acre tract on U.S. Corps of Engineers land below Lake Lewisville in Denton County, Texas. The site was partitioned into thirty-nine 40 by 40 meter plots with seeding (carried out in 1996) and management treatment (burning, mowing, and no maintenance carried out in 1998) randomly applied following a two level design. For each plot, nine stratified-random 0.1 m2 subplots were examined and shoot counts for each species recorded. The effects of the treatments on individual species and species richness were analyzed with a two-way ANOVA followed by a SNK multiple range test, both on ranked data. Community level analysis was conducted with both a MANOVA on ranked data and a Canonical Correspondence Analysis on raw data. Results indicate that seeding positively affected species richness, particularly when combined with either burning or mowing in the early spring. Mowing also significantly increased species richness in areas that were not seeded, while burning negatively affected species richness on unseeded plots. Treatments significantly affected community composition with treatments having the most clear effect on spring and summer forbs.

Jordens ekosystem och dess funktioner är och verkar på komplexa sätt, vilket människan är direkt ochindirekt beroende av för välfärd. På grund av mänsklig utveckling har förändrad markanvändningtryck undan ekosystem och begränsat dess möjligheter till funktion. Att implementera gröninfrastruktur är ett sätt att ge arter möjlighet att sprida sig mellan habitat och på så vis främjasekosystemens funktioner. Ekologisk konnektivitet är spridningsförmågan för liv mellan livsmiljöeroch grön infrastruktur är nödvändig för att det ska ske.Syftet med studien är att undersöka möjligheten till ekologisk konnektivitet för växten brunkulla inomett avgränsat område utifrån befintlig data, samt att utvärdera vilket kompletterande data som skullekunna ge en bättre bild av levnadssituationen och konnektivitet för orkidén.Studien är geografisk avgränsad till ett mindre område inom Storsjöbyggdens gräsvärdetrakt medLänsstyrelsen Jämtland Härlejdalens dokumentation över gräsvärdetrakter som utgångspunkt.Kartverktyget QGIS Desktop 3.10 with GRASS har använts i studien och data har hämtats frånJordbruksverket, Naturvårdsverket, Trafikverket, SMHI. Data som har använts är: nationellgräsmarksanalys, ängs- och betesmarksinventering, artrika väg- och järnvägsmiljöer, nationellmarktäckardata, vattenwebb, samt åtgärdsprogram för brunkulla.Resultatet visar att det finns en teoretisk möjligheten till ekologisk konnektivitet för växten brunkullainom det avgränsade området. Befintlig data kan även identifiera tänkbara habitat inom området. Dockbekräftar endast en datakälla att växten finns på en lokal inom det studerade området. För att få enbättre bild av levnadssituation och konnektivitet för orkidén inom området skulle kompletterande datasom: data med kalkrik-fosforfattig jordsammansätning inom området, data över var brunkulla blivitobserverad inom det utvalda området, fältbesök etc.Eftersom ett mindre område har valdes ut slumpmässigt för analys kan resultatet endast representeradet området. Eftersom brunkullas frö kan spridas med vind eller via vattendrag krävs att möjligahabitat ligger tätt och/eller att vatten flyter genom habitatet. En kartläggning av en arts möjlighet tillkonnektivitet ett kunskapasinsamlad som kan leda till stödjande åtgärder som i sin tur gynnarbiologisk mångfald långsiktigt. / The earth's ecosystems work in complex ways. The environment in the ecosystems together with lifecreate functions that humans are direct- and indirect dependent on. Due to human expansion throughdevelopment and change of land use, this has created pressure on the ecosystems and has limited itsability to function. Green infrastructure is a prerequisite for the ecosystems and their functions andcontributes to increased ecological connectivity. Through creating value areas and managing meadowandpastureland, knowledge is gained, and areas of high ecological value are being preserved. Actionprograms for endangered species and habitat is a way to save and preserve life that have decreased innumbers due to human activity. Actions like these are for preserving and benefit biodiversity. Thepurpose of the study is to investigate the possibility of ecological connectivity for Gymnadenia nigrawithin a defined area. The study is based on collected data, and an evaluate which supplementary datacould provide a better picture of the living situation and connectivity for the orchid.The study is geographically limited to a smaller area in Storsjöbyggden grassland values areas with thecounty administrative board of Jämtland Härlejdalen documentations of grassland values areas as astarting point. The mapping tool: QGIS Desktop 3.10 with GRASS has been used and data has beenretrieved from the Swedish National Board of Agriculture, The Swedish Environmental ProtectionAgency, The Swedish Transport Administration and The Swedish Meteorological and HydrologicalInstitute. Data that have been used is national grassland analysis, meadow- and pasture inventory, richroad and rail environments, national ground cover data, action program for endangered species etc.The results show that there is a theoretical possibility of ecological connectivity for the plantGymnadenia nigra within the demarcated area. Existing data can also identify possible habitats withinthe area. However, only one data source confirms that the plant is located at a local within the studiedarea. In order to get a better understanding of the living situation and connectivity of the orchid in theaera, additional data such as: data with lime-rich-phosphorus-poor soil density, data on whereGymnadenia nigra has been observed in the selected area, a field study, etc.Because a smaller area has been randomly selected for analysis, the result can only represent that area.If another area had been selected, the outcome would probably have been different. In order to get abetter picture, additional data would be needed, such as soil data for calcareous, phosphorus-poor soilas well as a field research to find possible habitat on site. Since the seeds of Gymnadenia nigra can bespread by wind or via watercourses, it is required that possible habitats are dense and / or that waterflows through the habitat. / <p>2021-11-26</p>

The urgent issue with a changing climate has shed a light on the agricultural system and related climate mitigatory opportunities. One natural climate solution that has reached a lot of attention during the later years is carbon sequestrations in soils. The pedosphere, the outermost layer of the earth, constitute a great carbon pool and does therefore possibly provide big opportunities to adjust carbon levels in the atmosphere. Several measures can be utilized to enhance carbon levels in soils but could possibly imply additional negative impacts on other sustainability aspects. One of these are biodiversity, which are a trait strongly connected to semi-natural grasslands. This study therefore presents an overview of the knowledge regarding carbon sequestration on semi-natural grasslands, framed in a Swedish context. Conflicts and synergies between the climate aspect and other values of semi-natural grasslands are here investigated. Firstly, a lack of reliable Swedish data was identified and problems with extrapolating data from international studies regarding soil carbon sequestration were pointed out, especially in the context of semi-natural grasslands and biodiversity. The report shows that Swedish semi-natural grasslands have a low level of carbon sequestration and moreover a low opportunity to act as a climate mitigator. Biodiversity is often a more prioritized factor for these lands and often interpreted as a hinder for climate mitigatory measures. There are, however, possible opportunities to improve the climatic impact these lands have, depending on several aspects, but do often require a broad system perspective. Synergies between climate and biodiversity were difficult to identify except the questioned statement that grazers possibly could enhance soil carbon sequestration and at the same time provide biodiversity benefits. Conflicts were based on difficulties in implementation of sequestration enhancing measures since they often, locally, implied impoverished biodiversity. / Klimatförändringar är ett aktuellt problem som även satt fokus på jordbrukets roll och dess möjligheter att minska dess koldioxidutsläpp och dämpa den globala uppvärmningen. En av de möjliga naturliga klimatlösningarna är att lagra kol i jorden. Pedosfären, jordskorpans yttersta skikt, är en stor kol-pool och utgör därför potentiellt en god möjlighet till att minska koldioxidhalten i atmosfären. Det finns flertalet möjligheter att öka kolinlagringen i jorden men dessa kan dock innebära negativa konsekvenser av andra hållbarhetsaspekter. En av dessa är biologisk mångfald, som är något som naturbetesmarker är starkt kopplade till. Denna studie presenterar en översikt över kolinlagring i naturbetesmarker i en svensk kontext. Konflikter och synergier mellan kolinlagring och andra värden av naturbetesmarker tas även upp. Först kan det nämnas att det finns osäkerheter i data från svenska naturbetesmarker och att data av kolinlagring från internationella studier ofta är svåra att extrapolera till svenska marker. Det fanns även få studier som behandlade både klimatperspektivet och biologisk mångfald på naturbetesmarker. Rapporten visar även att svenska naturbetesmarker har en låg nivå av kolinlagring och därmed en låg möjlighet att agera som en mildrande faktor gällande ett förändrat klimat, där en anledning är den begränsande totala ytan som finns definierad som naturbetesmark. Däremot finns det möjligheter att förändra klimatavtrycket dessa marker genererar. I en sådan ansats bör man inkludera en rad olika faktorer och använda ett brett systemperspektiv för vidare analys. Synergier är svåra att identifiera, bortsett från en ifrågasatt åsikt om att betande djur potentiellt båda kan bidra till biologisk mångfald och öka kolinlagringen på den betande marken. Konflikter utgörs ofta av svårigheten att många potentiellt kolinlagrande åtgärder hade direkt negativa konsekvenser för den biologiska mångfalden lokalt.

Modern tools, nontraditional datasets and a better understanding of the interaction between climate and ecohydrology are continuously being developed as today's society is in critical need for improving water management, predicting hydrometeorological hazards and forecasting future climate. In particular, the study of the intra- and inter-annual variations in grass productivity and evapotranspiration caused by variations in precipitation/soil moisture and other biophysical factors is of great significance due to their relation to future climatic changes. The research presented here falls in three parts. In the first part of the dissertation, a land use adaptable model, based on the superposition of the temperature and water vapor pressure effects, is proposed for the effective clear sky emissivity. Ground radiometer and meteorological data, applicable in the subtropical climate of Saint Johns River Water Management District, Florida, were utilized for the model development over the spring season of 2004. The performance of this model was systematically evaluated by pertinent comparisons with previously established models using data over various land covers. The second part of the thesis investigates the dynamics of evapotranspiration with respect to its significant environmental and biological controls over an unmanaged bahia grassland. Eddy correlation measurements were carried out at a flux tower in Central Florida over the annual course of 2004. The main focus was on the sensitivity of the water vapor flux to wetness variables, namely the volumetric soil water content and the current precipitation index. It was shown that the time scales involved with the dynamics of evapotranspiration were on the order of six days, suggesting that depletion of the soil moisture was mostly responsible for the temporal fluctuations in evapotranspiration. Finally, simple models for the Priestley-Taylor factor were employed in terms of water availability, and the modeled results closely matched the eddy covariance flux values on daily time scale during all moisture conditions. In the third part of this work, the partitioning between latent and sensible heat fluxes was systematically examined with respect to biophysical factors. It was found that the seasonal variations in leaf area index, soil water content and net radiation were reflected in a strong seasonal pattern of the energy balance. Calculations of the bulk parameters, namely Priestley-Taylor parameter and decoupling coefficient, indicated that evapotranspiration of this grassland was controlled by water supply limitations and surface conductance. At an annual basis, the cumulative evapotranspiration was 59 percent of the precipitation received at the site. The results of this research complemented with other studies will promote better understanding of land-atmosphere interactions, accurate parameterizations of hydroclimatic models, and assessment of climate impact of grassland ecosystems.

No description available.

No description available.

Covering around 30-40 % of the terrestrial surface, grasslands provide essential ecosystem functions vital for human well-being. Despite their importance, these ecosystems are under constant pressure from human intervention, leading to a tremendous decline in biodiversity. Consequently, monitoring and management efforts are urgently needed in order to preserve their biodiversity and ecological functions. Traditional biodiversity monitoring through in-situ vegetation surveys are the foundation of comprehensive biodiversity assessments. While these surveys provide detailed information on specific local plant communities, the resulting data are spatially confined to discrete sampling areas and repetitions are usually limited due to financial constraints. Nevertheless, the rapid ecosystem changes and the dramatic global biodiversity decline demand techniques that support large-scale biodiversity assessments at frequent intervals. Data collected by different remote sensing techniques, such as optical remote sensing, offer the potential to fulfill this need and significantly contribute to large-scale biodiversity monitoring. In optical remote sensing, sensors detect and analyze electromagnetic solar radiation reflected, emitted, or scattered from the Earth's surface. Plants interact with incident light by transmitting, absorbing, or reflecting it in different regions of the electromagnetic spectrum, creating a spectral reflectance pattern distinguishable from other surfaces on Earth. However, detecting grassland diversity from remote sensing data is particularly challenging due to the small size of individual grassland species, making them difficult to disaggregate even in high spatial resolution remote sensing data. Spectral pixel-to-pixel variability has been proposed as an approach to describe grassland diversity in remote sensing imagery. The fundamental premise, known as the Spectral Variability Hypothesis (hereafter SVH), suggests that increased spectral variability indicates a greater range of habitats within the surveyed region, potentially accommodating a larger number of species. Therefore, spectral variability, indirectly reflecting habitat diversity, is considered a potential indicator of taxonomic and trait diversity. Its applicability across different ecosystem types, seasons and spatial resolutions remains uncertain and highly debated within the vegetation remote sensing community. So far, the lack of comprehensive data has impeded systematic assessments of the SVH, which ideally would involve consistent sets of diversity estimates derived from both remote sensing data and in-situ plant diversity and trait measurements across different grassland habitat types. With this dissertation, I aimed to contribute to the effort of deriving ecologically relevant insights from remote sensing data to improve the monitoring and assessment of grassland biodiversity on large spatial scales. The research objectives of my thesis focused on the highly debated potential of spectral diversity for grassland diversity monitoring. Specifically, my thesis revolved around the following research objectives: 1. How reliable is the retrieval of leaf chlorophyll content using optical in-situ chlorophyll parameters in semi-natural grasslands with mixed species compositions and across seasons? 2. Is spectral pixel-to-pixel variation a reliable indicator of grassland biodiversity? What are the most promising spectral diversity indices for the biodiversity of grasslands? 3. Does spectral variability add adequate information to a classification algorithm based on multi spectral satellite data in order to facilitate a national biodiversity monitoring program? Based on the results of three studies, I draw the following conclusions: 1. Species, habitat and season significantly impacted LCC and spectral reflectance, indicating the importance of detailed ecological in-situ validation data to enhance the reliability of remote sensing products. Optical in-situ indicators for LCC should be adapted to the grassland community of interest. Especially in semi-natural grasslands with mixed species compositions, adapted protocols for pigment extraction are helpful to refine the results. The applied method emphasized the integration of field ecology techniques into remote sensing to enhance the quality of validation data for LCC products. 2. The relationship between spectral and species diversity was inconsistent across seasons and grassland types, with no spectral diversity metrics outperforming others. Thus, spectral variability from remote sensing data was not a reliable indicator for monitoring grassland diversity on a large scale. Based on 45,000 simulated grassland communities covering a broad gradient of taxonomic and functional diversity, species diversity did not directly translate into optical trait diversity. This suggested species diversity is not always reflected in spectral patterns. Interdisciplinary research will be required to enhance the reliability of remote sensing for monitoring grassland diversity. 3. Spectral variability proved less effective than hypothesized for classifying biodiversity categories within the German grassland diversity monitoring scheme. Harmonizing ecological survey data with spectral information retrieved from satellite remote sensing imagery was a major challenge. The current experimental design and target objects are not well-coordinated, impeding data transferability and the exploration of the full potential of remote sensing in ecological applications. In conclusion, interdisciplinary collaboration remains a crucial aspect of future research efforts. This is particularly relevant with regard to the extension of observation networks to cover the global distribution of grassland types, and the harmonization of validation protocols and field sampling schemes between remote sensing and ecological studies. Finally, spectral variability represents only one component of the comprehensive toolbox provided by remote sensing and ecology, which can assist in the better understanding and monitoring of grassland diversity.:1. Introduction 2. Original Contributions 2.1. Study 1 2.2. Study 2 2.3. Study 3 3. General Discussion 4. Outlook 5. Summary 6. References 7. Supplement 8. Author contribution statement 9. Acknowledgements 10. Declaration of Independence

Vegetation optical depth (VOD), as a microwave-based estimate of vegetation water and biomass content, is increasingly used to study the impact of global climate and environmental changes on vegetation. However, current global operational VOD products have a coarse spatial resolution (~25 km), which limits their use for agriculture management and vegetation dynamics monitoring at regional scales (1–5 km). This study aims to retrieve high-resolution VOD from the C-band Sentinel-1 backscatter data over a grassland of the Heihe River Basin in northwestern China. The proposed approach used an analytical solution of a simplified Water Cloud Model (WCM), constrained by given soil moisture estimates, to invert VOD over grassland with 1 km spatial resolution during the 2018–2020 period. Our results showed that the VOD estimates exhibited large spatial variability and strong seasonal variations. Furthermore, the dynamics of VOD estimates agreed well with optical vegetation indices, i.e., the mean temporal correlations with normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and leaf area index (LAI) were 0.76, 0.75, and 0.75, respectively, suggesting that the VOD retrievals could precisely capture the dynamics of grassland.

Die Untersuchungsschwerpunkte der vorliegenden Promotion, die von 1996-1999 im Rahmen des BMBF-Projektes "Auenregeneration nach Deichrückverlegung" im Biosphärenreservat Flusslandschaft Elbe - Brandenburg durchgeführt wurde, waren: - Lage und räumliche Verteilung der Vegetationstypen des Auengrünlandes in einem geplanten Rückdeichungsgebiet bei Lenzen (Elbe-km 476-484) im jetzigen Deichvor- und Deichhinterland - Erforschung der kausalen Zusammenhänge zwischen der jetzigen Vegetationszonierung im überflutungsgeprägten Deichvorland und den abiotischen und biotischen Standortsfaktoren vor Ort - aus den zwei erstgenannten Untersuchungen ableitend die Erstellung einer verbindlichen Prognose zur Zonierung der Grünlandvegetation nach der Deichrückverlegung (Übertragung der standortsbezogenen Untersuchungsergebnisse auf das Rückdeichungsgebiet im Geografischen Informationssystem GIS) - Auswirkung verschiedener Weide- und/oder Mahd-Nutzungsformen auf die jetzige Grünlandvegetation und Prognose der landwirtschaftlichen und naturschutzfachlichen Nutzungsmöglichkeiten nach einer Rückdeichung - Landschaftpflegerische Möglichkeiten zur Wiederansiedlung gefährdeter Stromtal-Arten nach einer Deichrückverlegung Anhand multivariater Verfahren (Kanonische Korrespondenzanalyse CCA, Hauptkomponentenanalyse DCA) konnte festgestellt werden, daß die mittlere jährliche Überflutungsdauer sich dazu eignet, die rezente Vegetationszonierung im Auengrünland zu beschreiben und zukünftige Vegetationsverteilung im Rückdeichungsgebiet zu prognostizieren. Die Überprüfung der Prognosergebnisse an Hand des rezenten, bereits überflutungsgeprägten Vordeichgrünlandes ergibt hohe bis sehr hohe Übereinstimmungen zwischen vorhergesagter und Ist-Vegetation bei wechselfrischen bis wechselfeuchten Grünlandbeständen der Typen Leucanthemo-Rumicetum thyrsiflori und Elytrigia repens-Alopecurus pratensis-Gesellschaft. Bei den wechselfeuchten bis wechselfrischen Flutrasen (Alopecuretum geniculati) und Rohrglanzgras-Röhrichten (Phalaridetum arundinaceae) weichen die Prognoseergebnisse in Flächenausdehnung und Kongruenz weiter von der rezenzten Vegetationsverteilung ab. Ursächlich sind hierfür vor allem das Mikrorelief des Deichvorlandes und seine Auswirkungen auf den Wasserzu- und abfluss während und nach Hochwässern verantwortlich. In der Diskussion werden die standortbezogenen Untersuchungesergebnisse mit ökologischen Modellen zur Sukzession und Überflutungstoleranz in Beziehung gesetzt. Das verwendete Prognosemodell wird anhand aktueller Literatur bewertet. Vor dem Hintergrund der weitreichenden hydrologischen Eingriffe in die Flussaue wird deutlich, dass nur solche Grünlandarten und -gesellschaften wieder angesiedelt werden können, die dynamische Grundwasserverhältnisse tolerieren. Eine Wiederbesiedlung kann mit Hilfe verschiedener Techniken aus nahegelegenen Restpopulationen im rezenten Deichvorland gelingen. / The investigations described in this study have been carried out between 1996 and 1999 as a part of the research project "Auenregeneration durch Deichrückverlegung" promoted by the German Federal Ministry of Education and Research (BMBF) in the "Mankind and the Biosphere" (MAB) reserve "Flusslandschaft Elbe - Brandenburg". The main objectives of the study were - to map the spatial distribution of different types of riparian grassland within a prospective re-inundation area near the town of Lenzen on the river Elbe (river kilometer 476-484) comprising the current grassland in front of the river dike and in its hinterland, - to quantify the influence of non-biotic and biotic site factors on temporarily inundated areas by thorough investigation of the present/current vegetation zonation of the dike's foreland, - to integrate the results of vegetation mapping and environmental research using a Geographical Information System (GIS) in order to predict the future vegetation zonation after the re-flooding of the proposed area, - to predict the impact of different types of land use on characteristic riparian grassland communities (extensive types of land use with hay harvest(ing) and grazing vs. hay harvest(ing) twice a year) with respect to nature preservation aspects and economic aspects of agricultural land use, and - to propose measures suitable to recover characteristic and endangered plant species and communities of riparian grassland after the setting back of the dike. By means of multivariate statistics (Canonical Correspondence Analysis CCA, Detrended Correspondence Analysis DCA) the mean annual duration of the inundation period was identified as a parameter suitable to describe the current grassland zonation and to predict the future zonation of the prospective re-inundation area. The results of the prediction were evaluated by comparing the predicted areas with the mapped areas of the present grassland types: The spatial distribution of the rarely flooded Leucanthemo-Rumicetum thyrsiflori and Elytrigia repens-Alopecurus pratensis grassland communities were highly congruent and matched well while the predicted and the mapped areas differed widely in more frequently flooded grassland types such as Alopecuretum geniculati and Phalaridetum arundinaceae These differences, however, were due to the microtopography of the dike's foreland (e. g. enbankments) governing the access and reflux of flooding water during inundation periods (site factor "isolation"). Furthermore the results of the evironmental studies were compared with current models of vegetation dynamics and inundation tolerance. The thus developed prediction model was evaluated. Taking the profound alterations in the hydrological characteristics of the flood plain into account it became evident that only those grassland species and communities that are able to tolerate highly dynamic ground water movements can be rehabilitated. Their restitution can be achieved by different techniques making use of left-over plant populations that can be found in the nearby grasslands of the dike's foreland.

Doctor of Philosophy / Department of Biology / Kimberly A. With / The loss, fragmentation, and degradation of grasslands have resulted in widespread declines in grassland birds. Nest predation is the leading cause of avian reproductive failure; therefore minimizing nest predation can lessen the severity of bird declines. Snakes are important predators of bird nests, but little is known about how snakes may enhance predation risk. To address this issue, I studied the habitat use, movement behavior, population genetic structure, and connectivity of snakes in the grasslands of northeastern Kansas. I addressed the connectivity of eastern yellowbelly racer (Coluber constrictor flaviventris) populations by using a landscape genetics approach at a broad scale (13,500 km2). I also radio-tracked the yellowbelly racer and Great Plains ratsnake (Pantherophis emoryi) at Konza Prairie Biological Station to understand their spatial ecology while simultaneously evaluating nest survival in grassland birds. Individual racers had limited dispersal (<3 km), but substantial admixture occurred within 30 km and populations were in migration-drift equilibrium and had high allelic diversity; therefore, racers must be abundant and continuously distributed for gene flow to be fluid throughout the region. Racers may be more likely to encounter bird nests, as they had more frequent movements and traversed greater distances on average than ratsnakes, which exhibited long periods of inactivity between directed movements. As for grassland birds, nest survival rates decreased with increasing shrubs and decreasing vegetation height. Discriminant function analysis revealed that successful nests were likely to occur in tall vegetation but reduced shrub cover, whereas higher shrub cover characterized snake habitats. Because snakes often use shrubs, nests in areas of increased shrubs may be at higher risk of predation by snakes. Targeted removal of shrubs may increase nest success by minimizing the activity of predators attracted to shrubs. Although predator removal is often a strategy for protecting bird populations, it may not be feasible in this instance, especially since snakes are a native component of the grassland community. Efforts to reduce snake predation on grassland bird nests should therefore focus on managing habitat within grasslands (i.e., shrubs) that influence snake activity, as no natural or anthropogenic habitat barriers currently limit snake movement across the landscape.