Human-driven climate, habitat, and land use changes often co-occur in ecological communities. We must consider the multiple components of global change acting on individual species and assemblages to document biological responses to environmental change and determine the mechanisms underlying these responses. Here, I examine climate, habitat, and land management impacts on a model aerial insectivore, the Tree Swallow (Tachycineta bicolor), and its insect prey. Both groups are undergoing population decline and phenological shifts in many parts of the world; however, the magnitude and mechanisms of these shifts are not well understood. I first document the impacts of temperature and precipitation on fall flight times of 20 butterfly species with varied life histories in Massachusetts. I find many butterfly species are flying later into the fall now than they were over 20 years ago; however, the response of butterflies to fall climate is complex and often mediated by life history characteristics, like number of broods per season. I then examine the effects of climate, habitat, and insect prey abundance on Tree Swallow reproduction to determine if anthropogenic changes in the breeding habitat result in declines in reproductive performance that contribute to population decline. I find that climate and foraging habitat impact egg laying phenology, clutch size, hatching success and fledging success of Tree Swallows. For example, reproductive phenology is delayed in rainy springs and fledging success is increased in nests with open water in their foraging radius. However, I find no evidence to indicate a change in insect abundance or anthropogenic changes, including climate and land management, are driving decreases in reproductive success of Tree Swallows over time. Lastly, I examine the effects of artificial nest management on Tree Swallow reproduction across Mass Audubon conservation areas. I find habitat, density, and predation of artificial nests to be strong and often overlooked determinants of Tree Swallows reproductive performance; for example, fledging is increased in nests placed in open habitat, far from forests and developed areas. This work provides novel evidence for the impacts of local-scale nest habitat and management on Massachusetts Tree Swallows, a threatened population of aerial insectivores.

Grasslands provide fundamental ecosystem services in many arid and semi-arid regions of the world, but are experiencing rapid increases in fire activity making them highly susceptible to post-fire accelerated soil erosion by wind. A quantitative assessment that integrates fire-wind erosion feedbacks is therefore needed to account for vegetation change, soil biogeochemical cycling, air quality, and landscape evolution. We investigated the applicability of a novel tracer technique – the use of multiple rare earth elements (REE) - to quantify aeolian soil erosion and to identify sources and sinks of wind-blown sediments in a burned and unburned shrub-grass transition zone in the Chihuahuan desert, NM, USA. Results indicate that the horizontal mass flux of wind-borne sediment increased approximately three times following the fire. The REE-tracer analysis of aeolian sediments shows that an average 88% of the horizontal mass flux in the control area was derived from bare microsites, whereas at the burned site it was derived from shrub and bare microsites, 42% and 39% respectively. The vegetated microsites, which were predominantly sinks of aeolian sediments in the unburned areas, became sediment sources following the fire. The burned areas exhibited a spatial homogenization of sediment tracers, highlighting a potential negative feedback on landscape heterogeneity induced by shrub encroachment into grasslands. Though fires are known to increase aeolian sediment transport, accompanying changes in the sources and sinks of wind-borne sediments likely influence biogeochemical cycling and land degradation dynamics. Our experiment demonstrated that REEs can be used as reliable tracers for field-scale aeolian studies. / Geology / Accompanied by one compressed .zip file: MET_Tower_Data.zip

Crop management practices, such as soil tillage and crop residue management, are land management activities with potentially large impacts on carbon (C) cycling and climate at the global scale. Improvements in crop management practices, such as conservation tillage or 'no-till' (NT), have been proposed as climate change mitigation measures because such practices may alter C cycles through increased sequestration of soil C in agricultural soils. Despite their potential importance, regional to global scale data are lacking for many crop management practices, and few studies have evaluated the potential impact of the full range of crop management practices on C cycling and climate at the global scale. However, monitoring of crop management practices is crucial for assessing spatial variations in management intensity and informing policy decisions. Inclusion of crop management practices in Earth system models used for assessing global climate is a key requirement for evaluating the overall effects of different crop management practices on C cycling and their potential to mitigate climate change. Studies in this dissertation seek to address these issues by: (1) evaluating the efficacy of remote sensing methods for monitoring differences in soil tillage and crop residue management practices in Iowa; (2) incorporating soil tillage practices into an Earth system model and assessing the potential for soil C sequestration and climate change mitigation through adoption of NT practices; (3) assessing the historical impact of including the full range of crop management practices (residue harvest, grain harvest, soil tillage, irrigation, and fertilization) on changes in C cycling associated with land use and land cover change (LULCC) to crops in an Earth system model. The remote sensing study found that performance of the minimum Normalized Difference Tillage Index (minNDTI) method for assessing differences in tillage and residue management was below average compared to previous studies, even when using imagery from both Landsat 8 and Sentinel-2A sensors. Accurate assessment of these practices using minNDTI was hindered by issues with image quality and inability to obtain sufficient cloud-free, time series imagery during the critical planting window. Remote sensing research aimed at obtaining regional to global scale data on tillage and residue management practices is likely to continue to face these issues in the future, but further research should incorporate additional sensors and assess the efficacy of the minNDTI method for multiple locations and years. Adoption of NT practices in the Community Land Model, which is the land component of the Community Earth System Model, resulted in a cumulative soil C sequestration of 6.6 – 14.4 Pg C from 2015 – 2100 under a future climate change scenario (Representative Concentration Pathway 8.5), and cumulative soil C sequestration was equal to approximately one year of present-day fossil fuel emissions. Adjusting for areas where NT is already practiced had minor impacts on cumulative soil C storage, reducing gains in soil C from NT adoption by 0.4 – 0.9 Pg C globally. These results indicate that soil C sequestration and potential for climate change mitigation through NT may be more limited than has been anticipated elsewhere. Soil C sequestration via NT adoption was highest in temperate regions of developed countries with high initial soil C contents, indicating these areas should be targeted for NT adoption. Simulating the full range of crop management practices in the Community Land Model resulted in an increase in C emissions due to LULCC of 29 – 38 Pg C compared to scenarios with generic crops and model defaults. Individual crop management practices with the largest impact on LULCC emissions were crop residue harvest (18 Pg C), followed by grain harvest (9 Pg C) and soil tillage (5 Pg C). Although implementation of crop residue harvest and soil tillage was extreme in this study, these results imply that Earth system models may underestimate emissions from LULCC by excluding the full range of crop management practices. Studies in this dissertation corroborate the importance of crop management practices for C cycling and climate, but further research on these management practices is needed in terms of data collection, improving process-level understanding, and inclusion of these practices in Earth system models. / Doctor of Philosophy

<p dir="ltr">This study explores the net return and risk associated with different farmland leases, focusing on the tenant’s perspectives. The types of leases investigated include cash rent, crop-share, and eight flex leases. Utilizing data from a case farm in west-central Indiana and employing the @Risk simulation software, the study assesses the financial performance and risk exposure of each lease type. The study's objectives include evaluating net return and risk through simulation models. Hypotheses suggest crop-share leases exhibit lower tenant risk, cash rent leases present higher tenant risk, and flex leases more effectively distribute risk between tenants and landlords. Results indicate that, for risk-averse operators, crop-share leases prove advantageous, while cash rent leases offer higher net returns at the expense of increased risk. Flex leases provide a balanced alternative, mitigating risk while achieving higher net returns than a crop share lease. Stochastic dominance analysis supports the suitability of crop-share and specific flex leases for various risk preferences. Downside risk analysis emphasizes the importance of considering the lower tails of net return distributions. The crop-share lease consistently demonstrates more favorable downside risk characteristics, making it an appealing choice for risk-averse tenants.</p><p dir="ltr">In conclusion, the study contributes valuable insights into the complexities of farmland leasing, offering a nuanced understanding of the trade-offs between net return and risk for different lease types. The results provide practical guidance for tenants seeking leases aligned with their risk preferences and financial goals.</p>

Drought is a climatic event regarding prolonged "drier than normal" conditions. Precipitation deficits, crop-moisture stress, soil-water unbalance, sudden stream flow cut-offs and low carrying capacity of ecosystems are responses to drought. Drought can occur in humid to arid climates, however, drought is more severe in arid and semi-arid areas due to the fact that in those distinctive areas, water resources are extremely limited and restricted. Additionally, local ecologies and ecosystems in arid regions are very fragile. Once a water competition occurs, critical services of ecosystems such as pure water, recreation, and land productivity will be threatened. This research focuses on prolonged drought events that have been occurring more frequently in a coastal province of South Central Vietnam – named Binh Thuan. The study area is distinctive because its climate is characterized as one of the driest provinces in Vietnam. Annual rainfall in the North and near the coast of the province is less than 800 mm per year. During 6 months of dry season, there is almost no rain, or less than 50 mm. Due to precipitation deficits and high surface temperatures in recent years, meteorological droughts have occurred more frequently, and lasted longer, thereby stressing water resources for vegetation, wildlife, households, and industry. The occurrence of prolonged droughts has constrained economic activities in the coastal areas, especially agriculture and aquaculture. Furthermore, a long duration of dry conditions coupled with unsustainable land management (such as overgrazing), "drought-sensitive" soils in areas with sand and barren lands may introduce and accelerate risks of desertification processes (land productivity deterioration and unable to recover). This research uses geospatial technologies to monitor drought severity and drought impacts on land use and land cover. Chapter 1 is a brief introduction and literature review of the drought context in Binh Thuan Province to place the research questions and objectives in content. Chapter 2 discusses the occurrence of meteorological droughts in Binh Thuan Province, then proposes climatic indices able to monitor this type of drought. Chapter 3 focuses on explaining and assessing uneven dry conditions that stressed vegetation health in the study area. This chapter investigates spatiotemporal distributions and frequencies of prolonged agricultural droughts using remotely sensed data and anomalies of precipitation distribution. Results indicate that coastal areas in the North of Binh Thuan are subject to severe droughts. Chapter 4 assesses human impacts on land management and practices in the study area during drought periods. Results show that in recent years (2010 to present), local governments and residents have implemented strategies to prevent sand dominance and to adapt to water shortages during dry seasons, such as vegetative cover, crop rotation with drought-tolerant plants and wind breaks. Accuracy was assessed using field data collected in the summer of 2016, in conjunction with Google Earth imagery. In summary, this dissertation enhances understanding of drought events and impacts in Binh Thuan Province by considering different types of drought - meteorological and agricultural drought, and interactions of drought and human impacts upon land management and land practices during dry periods. Furthermore, findings and results of this research have demonstrated the effectiveness of remotely sensed datasets, and other geospatial technologies, such as geographic information systems, in modeling drought severity and in examining efforts and drought-adaptive practices of local residents. This work is a valuable foundation on which further studies can build to support policy development to protect and reserve soil-land productivity in Binh Thuan and other coastal regions of Vietnam affected by prolonged droughts. / Doctor of Philosophy / Drought is a temporal climatic event with "drier than normal" conditions. While drought can occur in any climates, it can be more extreme in arid and semi-arid areas where annual rainfall and water resources are limited. Depending on types of drought, its presences and impacts may differ: (1) meteorological drought relates to a decrease of average rainfall/snowfall may resulting in moisture stress, (2) hydrological drought leads to a reduction of streamflow and groundwater, and (3) agricultural drought influences soil-water-crop balance or vegetation health. Prolonged drought – abnormally long duration of dry conditions, coupled with unsustainable management in water and land practice may cause losses of land productivity, promote soil erosion, and result in sand dominance in coastal areas. These land degradation processes can lead to "a desert-like condition" in impacted areas. This research concerns drought and its impacts in a coastal province in South central Vietnam, Binh Thuan. The study area is distinctive because its climate is characterized as one of the driest provinces in Vietnam. Annual rainfall in the North and near the coast is less than 800 mm per year, and during the 6 months of the dry season, there is almost no rain, or less than 50 mm. Due to precipitation deficits and high surface temperatures in recent years, meteorological droughts have occurred more frequently and lasted longer, stressing water resources for vegetation, wildlife, households, and industry. Additionally, unsustainable land management, such as overgrazing, coupled with movements of sand and barren lands from the coast inland, have accelerated the risks of land degradation. This research applies an integration of geospatial technologies for monitoring drought severity and impacts on land management and illustrates how local people have adapted to droughts.

Soil tillage is one of the most important agrotechnological processes having huge influence on the sowing, germination, growing, yield and quality of cultivated plants. At the same time soil tillage is one of the most expensive and energy consuming agrotechnological processes of plant cultivation. The conventional tillage technologies using mouldboard and intensive cultivation machinery have both a positive impact on the preparation of the seedbed for plants and a negative impact as they are rather detrimental to the environment, soil, its properties, biodiversity, pollution of water bodies, etc. During the conventional soil tillage the crop residues of the last yield are incorporated into the deeper layers of the soil and the soil surface is not covered. Such soils are much susceptible to the environmental forces and are easier disturbed by wind and water erosion. Every year around 6 mio ha of fertile soil areas are lost due to inappropriate agricultural activities and changing environmental conditions. Another very important factor is that deep ploughing is an unproductive soil tillage method pertaining to huge time and energy consumption. At the same time multiplex driving of heavy weight agricultural machinery over the soil results in negative influence on its peoperties as well as consuming of huge amounts of diesel fuel results in high pollution of the environment with the greenhouse gas. Therefore, in order to reduce the negative influence of agricultural activities... [to full text] / Žemės dirbimas yra vienas svarbiausių agrotechnologinių procesų, turinčių labai didelę įtaką kultūrinių augalų sėjai, sudygimui, augimui, derliui ir jo kokybei. Tuo pačiu žemės dirbimas yra ir vienas iš brangiausių ir energijai imliausių kultūrinių augalų auginimo agrotechnologinių procesų. Įprastinio žemės dirbimo technologijos, kuriose naudojamos verstuvinės ir intensyviai dirvą purenantys žemės dirbimo agregatai, greta teigiamo poveikio augalų sėklų guoliavietės paruošimui, yra pakankamai žalingos aplinkai, dirvai, jos savybėms, biologinei įvairovei, vandens telkinių taršai ir t.t. Įprastinio žemės dirbimo metu augalinės praėjusio derliaus liekanos yra įterpiamos į gilesnius dirvos sluoksnius ir dirvos paviršius lieka neuždengtas. Tokios dirvos yra žymiai jautresnės aplinkos veiksniams ir lengviau pažeidžiamos vėjo ir vandens erozijos. Kiekvienais metais, pasaulyje, dėl netinkamos žemės ūkio veiklos ir kintančių aplinkos sąlygų prarandama apie 6 mln. ha derlingų dirvos plotų. Kitas labai svarbus aspektas yra tas, kad žemės dirbimas gilaus arimo plūgais yra mažai našus, daug darbo laiko ir energijos sąnaudų reikalaujantis žemės dirbimas. Tuo pačiu daugkartinis didelės masės žemės ūkio agregatų važinėjimas po dirvą ne tik daro neigiamą įtaką jos savybėms, bet ir, sudeginant didelius kiekius dyzelinių degalų, stipriai teršia aplinką šiltnamio efektą sukeliančiomis dujomis. Todėl pastaruoju metu, siekiant mažinti žemės ūkio veiklos daroma neigiamą įtaką dirvos degradacijai... [toliau žr. visą tekstą]

Siekiant, kad į paviršinius vandens telkinius nepatektų pavojingų medžiagų, vandens telkinių krantai būtų apsaugoti nuo erozijos, būtų užtikrintas vandens telkinių pakrančių ekosistemų stabilumas, saugomas vandens telkinių pakrančių gamtinis kraštovaizdis bei jo estetinės vertybės yra nustatomos paviršinio vandens telkinio apsaugos zonos, o jų dalyje prie vandens telkinio nustatomos pakrantės apsaugos juostos. Kol kas Lietuvoje yra skiriamas mažas dėmesys pakrančių apsaugos juostom. Taigi šiose magistro tezėse aptariami pastaruoju metu Lietuvoje ir Europos sąjungoje naudojami teisės aktai ir reglamentai susiję su vandens apsauga ir pakrančių apsaugos juostomis. Šio magistrinio darbo metu buvo pasirinktas Nevėžio pabaseinio reguliuotas Trikojo upelis. Tyrimo metu buvo atlikta statistinė analizė, kuri parodė, kad Trikojo upelio pakrančių apsaugos juostos esminiai nesiskiria. Dauguma pakrančių apsaugos juostų pločiai 2,5 m. Buvo nustatyta, kad apsaugos juostos atitinka aplinkosauginius reikalavimus ties pievomis ir mišku. Taip pat buvo nustatinėjama sumedėjusios augalijos pasiskirstymas upelio šlaituose, rūšių skaičius ir tankis. / In order to protect surface water reservoirs against dangerous substances, to protect water reservoir banks from erosion, to ensure water reservoir coastal ecosystem stability, to save natural landscape of water reservoir coasts and its esthetical valuables, surface water reservoir protection zones are established. Coastal protection bands are determined in their proximity to water reservoir. Still, little attention is paid to coastal protection bands in Lithuania. This Master Thesis analyzes legal acts and regulation relative to water protection and coastal protection bands and valid in Lithuania and the European Union in present time. The regulated Trikojis streamlet of Nevėžis catchment basin was chosen for this Master Thesis. Statistical analysis was performed during this research, which showed no essential differences between Trikojis streamlet coastal protection bands. Most coastal protection bands were 2,5 m wide. It was determined, that protection bands meet the environmental protection requirements in meadow and forest regions. Ligneous vegetation division on the streamlet slopes was determined, so as the amount of its species and their density.

Šlapių žemių sausinimo įtaka nuotėkiui Lietuvoje vertinama nevienareikšmiškai. Darbe analizuojama Mūšos upės ties Ustukiais hidrologinės charakteristikos ir žemių sausinimo šioje baseino dalyje įtaka upės nuotėkiui. Darbui atlikti panaudoti 1960 – 2006 metų paros nuotėkio, metinio kritulių kiekio, vidutinės paros oro temperatūros duomenys ir nusausintų plotų apimtys. Sudarytas kritulių įtakos debitui grafikas, kuris parodo, kad šie rodikliai glaudžiai susiję. Nagrinėjami du laikotarpiai 1960-1981 metai iki patvenkiant Mūšos upę, ir 1983-2006 metai po Dvariukų tvenkinio įrengimo. Naudojant DHRAM programinę įrangą, išskirtos ir analizuotos 33 debito charakteristikos. Naudojant Mano–Kendalio testą nustatyti 33-jų hidrologinių charakteristikų kaitos trendai. Tyrimas parodė, kad žemių sausinimas didelės įtakos Mūšos upės nuotėkio pokyčiams nepadarė. Sausinimo poveikis pasireiškia maksimalių debitų sumažėjimu ir paros debitų pokyčiais. / Wet soil drainage on the runoff Lithuania controversial. The paper analyzes the beating of the river at Ustukiai hydrological characteristics and soil drainage in the basin of the river runoff influence. Used to carry out the 1960 - 2006 years of daily runoff, rainfall, average daily air temperature data and the volume of drained areas. Made in rainfall affect the flow graph, which shows that these indicators are closely related. Study of two periods of 1960-1981 years before damming Mūša river, and the 1983-2006 year Dvariukų pond construction. Using DHRAM software identified and analyzed the 33 characteristics of flow. Using Mann-Kendall test to determine their 33-hydrological characteristics of the change in trend. The study showed that the draining of lands affected by high river runoff beating did not change. The drainage effect of maximal decrease in discharges and daily discharges change.

Geodeziniai (kadastriniai) matavimai šiuo metu įgauna vis didesnę reikšmę. Magistro darbe išnagrinėti Lietuvos Respublikos įstatymai, vyriausybės nutarimai, kiti teisės aktai, straipsniai, internetinė informacija, susijusi su kadastrinių matavimų vykdymu, derinimu, kadastro duomenų suformavimu, jų įrašymu į duomenų bazę ir perspektyvomis, apžvelgta Tauragės rajone geodeziškai matuotų sklypų kitimo tendencijos per pastaruosius septynerius metus. Analizuojamas jų kiekis pagal tikslinę naudojimo paskirtį, atskirai aptariami žemės sklypų geodeziniai matavimai ir pasitaikančios problemos juos matuojant. Aptariamos problemos, galinčios atsirasti po žemės reformos pabaigos. Pateikiami konkretūs problemų, pasitaikančių vykdant kadastrinius matavimus, pavyzdžiai, aptariami jų sprendimo būdai ir pateikiamos išvados: blogai parengti žemės reformos žemėtvarkos projektai apsunkina kadastrinių matavimų atlikimą, įvertinus visas preliminariai blogai pamatuotų sklypų pasekmes, būtina kuo skubiau pereiti prie visų žemės sklypų kadastrinių matavimų, reikėtų pakeisti kai kuriuos teisės aktus siekiant užtikrinti geodezinių matavimų supaprastinamą. / Surveying (Cadastral) measurements are becoming increasingly important. Master's work to examine the Lithuanian law, government regulations and other laws, articles, online informatikon relating to the cadastral pursuit of cadastral the formation of the data and their inclusion in the database and the prospects looked Cesis district geodeziškai measured plots the trend over the past seven years. Analyzing the content for its intended use, are highlighted in the land of Geodesy and common problems they are measured. Deals with issues that may arise after the completion of land reform. Presented specific problems occurring in the cadastral measurements, the samples are discussed and solutions to the conclusion that a poor agricultural land reform projects are complicated by cadastral conducting a preliminary assessment of all the ill effects of measured sites, the urgency to go all the cadastral land parcels should be change some laws in order to ensure the simplification of the geodetic measurements.

Vienu iš pagrindiniu geologinės aplinkos teršėju yra laikomi sąvartynai. Todėl daugelyje šalių jie yra inventorizuojami ir tiriami, prognozuojamas jų poveikis gamtinei aplinkai. Lietuvai sąvartynų poveikio aplinkai problema taip pat labai aktuali. Todėl imtasi konkrečių priemonių informacijos apie sąvartynus kaupimui ir jų taršos mąsto įvertinimo. Tuo tikslu buvo atliekama ir iki šiol tebevykdoma sąvartynų inventorizacija. Kai kuriuose sąvartynuose buvo vykdomi įvairaus detalumo geologiniai-hidrogeologiniai tyrimai. Šiame darbe analizuojama Jerubaičių sąvartyno filtrato dinamika. Pateikiama sąvartyne susikaupusio filtrato judėjimo schema. Bei jo valymas atvirkštinės osmozės būdu. Tiriamas filtrato kiekio kitimas keičiantis meteorologinėm sąlygom, analizuojamas laikotarpis nuo 2008.05.15 iki 2008.12.31. Tiriamas laikotarpis, nuo gegužės 15 iki sausio 1, apima visus metų laikus bei atspindi tipines Lietuvos meteorologinės sąlygos. Darbe tiriama filtrato susidarymo priklausomybė sąvartyne nuo atvežamų šiukšlių kiekio ir meteorologinių sąlygų. Duomenys pateikiami grafiškai juos apdorojus, duomenų statistiniam apdorojimui panaudota programa STATISTICA. / Landfill is considered as one of the main geo-environmental polluters. Therefore, in most countries they are inventoried, analyzed and forecast their impact for the natural environment. Lithuania landfill’s environmental problem is also relevant. Consequently, there are taken appropriate actions about landfills and their accumulation of pollution assessment. This was done and it is still ongoing landfill inventory. In some landfills there were carried out a wide range of detail geological-hydrogeological researches. This document analyzes Jėrubaičiai landfill leachate dynamics. There is available landfill leachate accumulated movement scheme and its cleaning by reverse osmosis method. This analysis shows leachate flow dynamics in different meteorological conditions. Research period was from 2008.05.15 to 2008.12.31. Selected research period is covering all seasons and represents Lithuanian meteorological conditions. In this document explored formation of leachate dependency from incoming garbage amount and weather conditions. Research data are represented graphically; program STATISTICA was used for statistical data processing.