Bibliografie tematiche / Arid Ecosystem

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Letteratura scientifica selezionata sul tema "Arid Ecosystem"

Autore: Grafiati
Pubblicato: 28 settembre 2024

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Articoli di riviste sul tema "Arid Ecosystem"

1

Zhou, Yanqing, Yaoming Li, Wei Li, Feng Li e Qinchuan Xin. "Ecological Responses to Climate Change and Human Activities in the Arid and Semi-Arid Regions of Xinjiang in China". Remote Sensing 14, n. 16 (12 agosto 2022): 3911. http://dx.doi.org/10.3390/rs14163911.

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Abstract (sommario):
Understanding the impacts and extent of both climate change and human activities on ecosystems is crucial to sustainable development. With low anti-interference ability, arid and semi-arid ecosystems are particularly sensitive to disturbances from both climate change and human activities. We investigated how and to what extent climate variation and human activities influenced major indicators that are related to ecosystem functions and conditions in the past decades in Xinjiang, a typical arid and semi-arid region in China. We analyzed the changing trends of evapotranspiration (ET), gross primary productivity (GPP) and leaf area index (LAI) derived from the Moderate-Resolution Imaging Spectroradiometer (MODIS) satellite product and the Breathing Earth System Simulator (BESS) model in Xinjiang for different climate zones. We separated and quantified the contributions of climate forcing and human activities on the trends of the studied ecosystem indicators using the residual analysis method for different climate zones in Xinjiang. The results show that GPP and LAI increased and ET decreased from 2001 to 2015 in Xinjiang. Factors that dominate the changes in ecosystem indicators vary considerably across different climate zones. Precipitation plays a positive role in impacting vegetation indicators in arid and hyper-arid zones and temperature has a negative correlation with both GPP and LAI in hyper-arid zones in Xinjiang. Results based on residual analysis indicate that human activities could account for over 72% of variation in the changes in each ecosystem indicator. Human activities have large impacts on each vegetation indicator change in hyper-arid and arid zones and their relative contribution has a mean value of 79%. This study quantifies the roles of climate forcing and human activities in the changes in ecosystem indicators across different climate zones, suggesting that human activities largely influence ecosystem processes in the arid and semi-arid regions of Xinjiang in China.
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2

Cai, Peng, Chaofan Li, Geping Luo, Chi Zhang, Friday Uchenna Ochege, Steven Caluwaerts, Lesley De Cruz et al. "The Responses of the Ecosystems in the Tianshan North Slope under Multiple Representative Concentration Pathway Scenarios in the Middle of the 21st Century". Sustainability 12, n. 1 (6 gennaio 2020): 427. http://dx.doi.org/10.3390/su12010427.

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Abstract (sommario):
The arid ecosystem is fragile and sensitive to the changes in climate and CO2 concentration. Exploring the responses of the arid ecosystem to the changes under different representative concentration pathways (RCPs) is of particular significance for the sustainable development of the ecosystem. In this study, the dynamics of net primary productivity (NPP), evapotranspiration (ET), and water use efficiency (WUE) for arid ecosystems in Tianshan North Slope are explored by running the arid ecosystem model at 25 km resolution under RCP2.6, RCP4.5, and RCP8.5. The climate in Tianshan North Slope presents a wet-warming trend during 2006–2055 under each RCP scenario with temporal and spatial heterogeneity. In response to the changes in climate and CO2, the regional annual NPP and ET increased during 2006–2055 by a respectively maximum rate of 2.15 g C m−2 year−1 and 0.52 mm year−1 under RCP8.5. Both the NPP and ET share a similar temporal and spatial heterogeneity with climate change. Different vegetation types respond differently to the changes under different RCP scenarios with increasing WUE. Under each RCP, the non-phreatophyte, phreatophyte, and grass are more sensitive to the changes than in the others, and the broadleaf forest and cropland are less sensitive to the changes.
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Fan, Xue, Xingming Hao, Haichao Hao, Jingjing Zhang e Yuanhang Li. "Comprehensive Assessment Indicator of Ecosystem Resilience in Central Asia". Water 13, n. 2 (7 gennaio 2021): 124. http://dx.doi.org/10.3390/w13020124.

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The ecosystems in the arid inland areas of Central Asia are fragile and severely degraded. Understanding and assessing ecosystem resilience is a challenge facing ecosystems. Based on the net primary productivity (NPP) data estimated by the CASA model, this study conducted a quantitative analysis of the ecosystem’s resilience and comprehensively reflected its resilience from multiple dimensions. Furthermore, a comprehensive resilience index was constructed. The result showed that plain oasis’s ecosystem resilience is the highest, followed by deserts and mountainous areas. From the perspective of vegetation types, the highest resilience is artificial vegetation and the lowest is forest. In warm deserts, the resilience is higher in shrubs and meadows and lower in grassland vegetation. High coverage and biomass are not the same as the strong adaptability of the ecosystem. Moderate and slightly inelastic areas mainly dominate the ecosystem resilience of the study area. The new method is easy to use. The evaluation result is reliable. It can quantitatively analyze the resilience latitude and recovery rate, a beneficial improvement to the current ecosystem resilience evaluation.
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Fan, Xue, Xingming Hao, Haichao Hao, Jingjing Zhang e Yuanhang Li. "Comprehensive Assessment Indicator of Ecosystem Resilience in Central Asia". Water 13, n. 2 (7 gennaio 2021): 124. http://dx.doi.org/10.3390/w13020124.

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Abstract (sommario):
The ecosystems in the arid inland areas of Central Asia are fragile and severely degraded. Understanding and assessing ecosystem resilience is a challenge facing ecosystems. Based on the net primary productivity (NPP) data estimated by the CASA model, this study conducted a quantitative analysis of the ecosystem’s resilience and comprehensively reflected its resilience from multiple dimensions. Furthermore, a comprehensive resilience index was constructed. The result showed that plain oasis’s ecosystem resilience is the highest, followed by deserts and mountainous areas. From the perspective of vegetation types, the highest resilience is artificial vegetation and the lowest is forest. In warm deserts, the resilience is higher in shrubs and meadows and lower in grassland vegetation. High coverage and biomass are not the same as the strong adaptability of the ecosystem. Moderate and slightly inelastic areas mainly dominate the ecosystem resilience of the study area. The new method is easy to use. The evaluation result is reliable. It can quantitatively analyze the resilience latitude and recovery rate, a beneficial improvement to the current ecosystem resilience evaluation.
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Mugari, Ephias, Hillary Masundire, Maitseo Bolaane e Mark New. "Perceptions of ecosystem services provision performance in the face of climate change among communities in Bobirwa sub-district, Botswana". International Journal of Climate Change Strategies and Management 11, n. 2 (8 marzo 2019): 265–88. http://dx.doi.org/10.1108/ijccsm-09-2017-0178.

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PurposeBetween 2006 and 2016, local communities in semi-arid Bobirwa sub-district in the Limpopo Basin part of Botswana had endured notable fluctuations in the delivery of critical ecosystem services. These changes have been coupled with adverse effects on local people’s livelihood options and well-being. However, a few such studies have focussed on the semi-arid to arid landscapes. This study therefore aims to provide recent knowledge and evidence of consequences of environmental change on semi-arid arid landscapes and communities.MethodologyTo examine these recent changes in key ecosystem services, the authors conducted six participatory mapping processes, eight key informant interviews and several rapid scoping appraisals in three study villages. The analyses were centred on changes in seasonal quantities, seasonality, condition of ecosystem service sites, distance to ecosystem service sites and total area providing these services. Drivers of change in the delivery of key ecosystem services and the associated adverse impacts on human well-being of these recent changes in bundles of ecosystem services delivered were also analyzed.FindingsResults show that adverse weather conditions, drought frequency, changes in land-use and/or land-cover together with unsustainable harvesting because of human influx on local resources have intensified in the past decade. There was circumstantial evidence that these drivers have resulted in adverse changes in quantities and seasonality of key ecosystem services such as edible Mopane caterpillars, natural pastures, wild fruits and cultivated crops. Similarly, distance to, condition and total area of sites providing some of the key ecosystem services such as firewood and natural pastures changed adversely. These adverse changes in the key ecosystem services were shown to increasingly threaten local livelihoods and human well-being.Research limitations/implicationsThis paper discusses the importance of engaging rural communities in semi-arid areas in a participatory manner and how such information can provide baseline information for further research. The paper also shows the utility of such processes and information toward integrating community values and knowledge into decisions regarding the management and utilization of local ecosystem services under a changing climate in data-poor regions such as the Bobirwa sub-district of Botswana. However, the extent to which this is possible depends on the decision makers’ willingness to support local initiatives through existing government structures and programmes.Originality/valueThis study shows the importance of engaging communities in a participatory manner to understand changes in local ecosystem services considering their unique connection with the natural environment. This is a critical step for decision makers toward integrating community values in the management and utilization of ecosystem services under a changing climate as well as informing more sustainable adaptive responses in semi-arid areas. However, the extent to which decision makers can integrate such findings to inform more sustainable responses to declining capacity of local ecosystems in semi-arid areas depends on how they value the bottom-up approach of gaining local knowledge as well as their willingness to support local initiatives through existing government structures and programmes.
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Guan, K., S. P. Good, K. K. Caylor, H. Sato, E. F. Wood e H. Li. "Continental-scale impacts of intra-seasonal rainfall variability on simulated ecosystem responses in Africa". Biogeosciences 11, n. 23 (11 dicembre 2014): 6939–54. http://dx.doi.org/10.5194/bg-11-6939-2014.

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Abstract. Climate change is expected to modify intra-seasonal rainfall variability, arising from shifts in rainfall frequency, intensity and seasonality. These intra-seasonal changes are likely to have important ecological impacts on terrestrial ecosystems. Yet, quantifying these impacts across biomes and large climate gradients is largely missing. This gap hinders our ability to better predict ecosystem services and their responses to climate change, especially for arid and semi-arid ecosystems. Here we use a synthetic weather generator and an independently validated vegetation dynamic model (SEIB-Dynamic Global Vegetation Model, DGVM) to virtually conduct a series of "rainfall manipulation experiments" to study how changes in the intra-seasonal rainfall variability affect continent-scale ecosystem responses across Africa. We generate different rainfall scenarios with fixed total annual rainfall but shifts in (i) frequency vs. intensity, (ii) rainy season length vs. frequency, (iii) intensity vs. rainy season length. These scenarios are fed into SEIB-DGVM to investigate changes in biome distributions and ecosystem productivity. We find a loss of ecosystem productivity with increased rainfall frequency and decreased intensity at very low rainfall regimes (<400 mm year−1) and low frequency (<0.3 event day−1); beyond these very dry regimes, most ecosystems benefit from increased frequency and decreased intensity, except in the wet tropics (>1800 mm year−1) where radiation limitation prevents further productivity gains. This result reconciles seemingly contradictory findings in previous field studies on the impact of rainfall frequency/intensity on ecosystem productivity. We also find that changes in rainy season length can yield more dramatic ecosystem responses compared with similar percentage changes in rainfall frequency or intensity, with the largest impacts in semi-arid woodlands. This study demonstrates that intra-seasonal rainfall characteristics play a significant role in influencing ecosystem function and structure through controls on ecohydrological processes. Our results suggest that shifts in rainfall seasonality have potentially large impacts on terrestrial ecosystems, and these understudied impacts should be explicitly examined in future studies of climate impacts.
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Alqallaf, Ahmed, Bader Al-Anzi e Meshal Alabdullah. "Assessing the Effectiveness of Supplemental Irrigation to Improve Soil Moisture in an Arid Ecosystem with an Emphasis on Climate Change: A Case Study from the State of Kuwait". Sustainability 12, n. 21 (1 novembre 2020): 9104. http://dx.doi.org/10.3390/su12219104.

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Arid ecosystems are extremely vulnerable to climate change, which is considered one of the serious global environmental issues that can cause critical challenges to the hydrological cycle in arid ecosystems. This work focused on assessing the effectiveness of supplemental irrigation to improve the actual soil moisture content in arid ecosystems and considering climate change impacts on soil moisture. The study was conducted at two fenced protected sites in Kuwait. The first site is naturally covered with Rhanterietum epapposum, whereas the other study site is a supplemented irrigated site, containing several revegetated native plants. The results showed that supplemental irrigation highly improved soil moisture (∆SM) during the winter season by >50%. However, during the summer season, the rainfed and irrigated site showed low ∆SM due to the high temperature and high evapotranspiration (ET) rates. We also found that ∆SM would negatively get impacted by climate change. The climate change projection results showed that temperature would increase by 12%–23%, ET would increase by 17%–19%, and precipitation would decrease by 31%–46% by 2100. Such climate change impacts may also shift the current ecosystem from an arid to a hyper-arid ecosystem. Therefore, we concluded that irrigation is a practical option to support the ∆SM during the low-temperature months only (spring and winter) since the results did not show any progress during the summer season. It is also essential to consider the possibility of future shifting in ecosystems and plant communities in restoration and revegetation planning.
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Sun, Yihan, Guang Zhao, Zhoutao Zheng, Yixuan Zhu, Juntao Zhu, Yangping Di, Jie Gao, Mengke Cai e Yangjian Zhang. "Wetting-warming climate increases ecosystem carbon use efficiency of Chinese arid and semi-arid ecosystem". Agricultural and Forest Meteorology 351 (maggio 2024): 110018. http://dx.doi.org/10.1016/j.agrformet.2024.110018.

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Fan, Xin, Haoran Yu, Damien Sinonmatohou Tiando, Yuejing Rong, Wenxu Luo, Chan Eme, Shengya Ou, Jiangfeng Li e Zhe Liang. "Impacts of Human Activities on Ecosystem Service Value in Arid and Semi-Arid Ecological Regions of China". International Journal of Environmental Research and Public Health 18, n. 21 (22 ottobre 2021): 11121. http://dx.doi.org/10.3390/ijerph182111121.

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The quantitative and spatial–temporal variations in the characteristics of ecosystem value can be helpful to improve environmental protection and climate adaptation measures and adjust the balance between economic development and the ecological environment. The arid and semi-arid regions of China are undergoing the effects of climate change across the entire northern hemisphere. Their ecological environments are fragile and in conflict with anthropogenic activities, which significantly altered more ecosystems services in these regions. Therefore, estimating the effects of anthropogenic activities on ecosystem services is important for formulating ecological policy and regional environmental mitigation plans of these regions. This study employed the model of ecosystem service value (ESV) assessment and the bivariate spatial autocorrelation method to reveal the spatiotemporal variations in the characteristics of ecosystem value in the arid and semi-arid ecological regions of China and its interaction with human activities. Results showed that (1) the total value of ES of the study area increased from USD 487,807 billion in 2000 to USD 67,831,150 billion 2020; (2) the ES value provided by forest land first increased by 5.60% from 2000 to 2020; (3) the ESV provided by grassland showed an overall decline over the 20 years. Food and raw material production showed the lowest ES value, and climate regulation and soil conservation decreased from 2000 to 2020; (4) the index of human footprint patches decreased from 45.80% in 2000 to 17.63% in 2020, while the high and very high human footprint index areas increased significantly, mainly due to the rapid urbanization and improvement of railway networks in these areas. Spatially, the regions with high human footprint were mostly dispersed in the northeastern of China such as Shanxi and Gansu, whereas the regions with a low human footprint remained mainly located in the central and southwestern parts of China; (5) significant spatial dependencies between changes in ESV and the human footprint index were recorded. Our study could provide a scientific basis for ecosystem functions regulation and land development security in arid and semi-arid ecological regions.
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Luković, Milica, e Urban Šilc. "Management of continental saline ecosystems in the Republic of Serbia: Are these ecosystems suitable for nature-based tourism?" Menadzment u hotelijerstvu i turizmu 9, n. 2 (2021): 37–49. http://dx.doi.org/10.5937/menhottur2102037l.

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Continental saline habitats represent unique, authentic and rare ecosystems. These ecosystems are typically distributed in arid and semi-arid regions; however, they are also found in inland areas in temperate climate zones. Usually, the general public is not familiar with this particular type of ecosystem. In order to present saline habitats to tourists, a broadly applied method of ecosystem suitability assessment (ESI-ecosystem suitability index) was used and adjusted to the purposes of this research. The research aims to estimate the nature-based tourism potentials of selected sites. Thus, six representative halophytic habitats distributed along the geographic gradient, from the Pannonian Plain to the south of Serbia, were chosen. In terms of each site, seven indicators (e.g., flora and vegetation, bird fauna, landscape, protection status, accessibility, and ecotourism facilities), important for nature-based tourism, were analyzed. The results show that the Pannonian saline habitats have greater opportunities for development of this type of tourism in almost all categories compared to southern sites.
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Più fonti

Tesi sul tema "Arid Ecosystem"

1

Giardina, Mariah. "Challenges and Strategies for Spring Ecosystem Restoration in the Arid Southwest". Arizona-Nevada Academy of Science, 2011. http://hdl.handle.net/10150/296987.

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2

Whittington-Jones, Gareth Morgan. "The role of aardvarks (Orycteropus afer) as ecosystem engineers in arid and semi-arid landscapes of South Africa". Thesis, Rhodes University, 2007. http://hdl.handle.net/10962/d1005445.

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Abstract (sommario):
Arid and semi arid environments are characterised by extreme fluctuations in temperature and low rainfall which present significant challenges to the animals inhabiting these areas. Mammals, such as aardvarks (Orycteropus afer, Pallas 1766), excavate burrows in order to avoid predators and climatic extremes and are termed “ecosystem engineers” as they physically modify their environment and in doing so create new habitats and alter the availability of resources to other species. In this study I assessed the microhabitat conditions (maximum and minimum temperature, relative humidity and seed abundance) of aardvark burrows in relation to paired control sites. In addition, I evaluated the use of aardvark burrows by other vertebrate and invertebrate species and investigated the impact of aardvark burrow mounds on landscape scale floristic diversity. Maximum temperatures were significantly lower (p < 0.05) and minimum temperatures and midday humidity were significantly higher (p < 0.05) inside the burrows at the three study sites, Kwandwe Private Game Reserve (Kwandwe), Mountain Zebra National Park (MZNP) and Tswalu Kalahari Reserve (Tswalu). There were no significant differences between the concentration of seeds, the average numbers of unique individual small mammals, trap success or small mammal species richness recorded inside the burrows compared to outside (p > 0.05). At all three sites, small mammal species diversity was higher in the burrows but this result was also not significant (p > 0.05 for all). Trap success and the number of individuals captured was higher at Tswalu than the other two sites (p < 0.05 for both). The different methods used in this study revealed a total of 25 mammal, seven bird, one amphibian and six reptile species utilising aardvark burrows. There were significant differences in insect community assemblages between the burrows and open control areas at Kwandwe and Tswalu (p < 0.05 for both) but not at MZNP (p > 0.05). The parasitic guild was more prominent inside the burrows than outside but their abundance was not as high as anticipated, possibly due to the placement of traps closer to the burrow entrances than the sleeping chambers. The complex structure of the burrows prevented the placement of traps in close proximity to the sleeping chambers. As expected, the amount of bare earth was significantly higher on active and recently abandoned burrow mounds compared to the old burrow mounds and reference plots at all three sites (p < 0.05 for all), with the exception of the active burrows at Tswalu. Overall, the different plot types were characterised by significantly different plant communities during all the seasons at MZNP, during three of the seasons at Kwandwe and only during winter at Tswalu. The total species richness recorded on the reference plots was higher than on the burrow mounds at all three sites. However, species diversity on the reference plots was not significantly higher than the burrows at any of the sites (p > 0.05 for all sites). Although the results were not significant, the overall species diversity at a site level was greater than the reference patches at Kwandwe and Tswalu (p > 0.05 for both). Aardvarks fulfil the criteria of a significant ecosystem engineer and their presence in arid and semi-arid environments is likely to be critical to the survival of other individual organisms and species, particularly when alternative burrowing animals are either absent or restricted in their activities. Thus, aardvark populations should be considered a conservation priority in arid and semi-arid ecosystems.
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Snyder, Keirith A. 1967. "Patterns of plant species diversity and composition in a semi-arid riparian ecosystem". Thesis, The University of Arizona, 1995. http://hdl.handle.net/10150/278513.

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Understanding plant community structure is fundamental to successful restoration and conservation of riparian ecosystems. High plant species diversity is often cited as an important characteristic of riparian areas. Graphical summaries, principal components analysis, and analysis of variance were used on species composition and abundance data to determine community patterns in riparian areas and surrounding uplands. Woody plant composition varied with relative elevation above the primary channel, but herbaceous composition appeared unaffected by proximity to the riparian area. Alpha diversity indices, richness, Shannon's H', and Simpson's D, were not always higher within the riparian area. Alpha diversity of woody plants demonstrated no consistent pattern, however vertical structural diversity was highest near the stream. Herbaceous plants showed increased diversity in floodplain sites and decreased diversity in hillslopes sites, suggesting that topographical profile influenced diversity. Herbaceous richness was better predicted from overstory characteristics than herbaceous biomass and environmental variables.
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Maphangwa, Khumbudzo Walter. "Lichen thermal sensitivities, moisture interception and elemental accumulation in an arid South African ecosystem". Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_7139_1307950118.

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Elevated temperatures accompanying climate warming are expected to have adverse effects on sensitive lichen species. This premise was examined by measuring the sensitivity of different lichen species to elevated temperatures in the laboratory and in the field. Laboratory studies involved the exposure of nine hydrated lichen species (Xanthoparmelia austro-africana, X. hyporhytida, Xanthoparmelia sp., Xanthomaculina hottentotta, Teloschistes capensis, Ramalina sp., Flavopuntelia caperata, Lasallia papulosa, Parmotrema austrosinensis) collected from sites of different aridity and mean annual temperature for 2 hourly intervals to temperatures ranging from 24º
C to 48º
C in a forced daft oven and measuring their respiration rates and maximum quantum yield of PSII. Field studies involved simultaneous hourly measurements of ground surface air temperatures and Lichen effective quantum yield of PSII of hydrated lichen species populations under ambient and artificially modified environmental conditions.

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James, Alexandra Iona Biological Earth &amp Environmental Sciences Faculty of Science UNSW. "Development of resource-rich patches by soil-disturbing animals in arid environments". Awarded by:University of New South Wales. Biological, Earth & Environmental Sciences, 2009. http://handle.unsw.edu.au/1959.4/44353.

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In arid landscapes limited resources are concentrated into fertile patches that allow greater productivity than would otherwise be expected. Fertile patches are created and maintained by processes that modify soil topography and interrupt the flow of resources across the landscape. These processes may be abiotic or biotic in origin. Species that modify, maintain or create habitat have been termed ecosystem engineers. One group of soil disturbing ecosystem engineers creates fertile patches by modifying soil microtopography through foraging for food and creating habitat. This thesis examines the effects of soil foraging animals on resource concentration in arid environments and how effects are moderated by species and landscape. Chapter 1 provides an overview of the importance of fertile patches in arid systems and describes previous research on the effects of ecosystem engineers in arid environments. Chapter 2 examines how fertile patch creation by a well-studied arid zone engineer, the ant, varies between ant species and landforms, demonstrating that while we can generalise about the effects of ant nests on water flow and nutrient levels, differences in soil type, nest density and ant species across sites are likely to moderate these effects. Chapters 3, 4 and 5 compare the engineering effects of reintroduced native species, the Greater bilby (Macrotis lagotis) and Burrowing bettong (Bettongia lesueur) with the Sand goanna (Varanus gouldii) and the invasive European rabbit (Oryctolagus cuniculus) across three Australian landforms, revealing differences between reintroduced and invasive engineers at the both patch and landscape scales. At the landscape scale, differences in pit densities and resource concentration in foraging pits between landforms suggest that fertile patch development is not uniform. Chapter 6 examines whether the structure of the pit or the presence of litter per se explains observed increases in plant germination in foraging pits, and compares temperature and soil moisture conditions in bilby and bettong pits to the soil surface. Chapter 7 is a review that builds upon previous chapters, published and unpublished literature of the potential for reintroductions of ecosystem engineers to restore ecosystem function in degraded environments. Chapter 8 summarises the research presented in this thesis and its implications, and suggests directions for future work.
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Petersen, Leif Michael. "Granivores as ecosystem regulators of woody plant increasers in semi-arid Savannas of the Lowveld, South Africa". Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_8725_1210750329.

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In recent years, a global trend of increasing woody vegetation densities in semi-arid savanna habitats has been recorded, commonly described in South Africa as 'bush encroachment'. The shrubs and trees that do this (Increasers) have wrought significant economic and ecological impacts upon carrying capacities of large areas of savannas. This occurs, as suitable grazing areas are incrementally engulfed in shrubs and trees establishing new equilibria, from open savannas (essentially grasslands with scattered trees) into closed woodlands (treelands with scattered grasses). This thesis demonstrated a link between grass biomass, small mammal abundance and diversity, and their potential increaser seed/seedling predatory activities in the semi-arid Lowveld Savannas of South Africa.

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Aralova, Dildora, Kristina Toderich, Ben Jarihani, Dilshod Gafurov, Liliya Gismatulina, Babatunde A. Osunmadewa e Abualgasim Majdaldin Rahamtallah. "Environmental resilience of rangeland ecosystems: Assessment drought indices and vegetation trends on arid and semi-arid zones of Central Asia". SPIE, 2016. https://tud.qucosa.de/id/qucosa%3A35118.

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The Central Asian (CA) rangelands is a part of the arid and semi-arid ecological zones and spatial extent of drylands in CA (Tajikistan, Kazakhstan, Uzbekistan, Kyrgyzstan, and Turkmenistan) is vast. Projections averaged across a suite of climate models, as measured between 1950-2012 by Standardised Precipitation-Evapotranspiration Index (SPEI) estimated a progressively increasing drought risks across rangelands (Turkmenistan, Tajikistan and Uzbekistan) especially during late summer and autumn periods, another index: Potential Evapotranspiration (PET) indicated drought anomalies for Turkmenistan and partly in Uzbekistan (between 1950-2000). On this study, we have combined a several datasets of drought indices ( SPIE, PET, temperature_ToC and precipitation_P) for better estimation of resilience/non-resilience of the ecosystems after warming the temperature in the following five countries, meanwhile, warming of climate causing of increasing rating of degradations and extension of desertification in the lowland and foothill zones of the landscape and consequently surrounding experienced of a raising balance of evapotranspiration (ET0). The study concluded, increasing drought anomalies which is closely related with raising (ET0) in the lowland and foothill zones of CA indicated on decreasing of NDVI indices with occurred sandy and loamy soils it will resulting a loss of vegetation diversity (endangered species) and raising of wind speeds in lowlands of CA, but on regional level especially towards agricultural intensification (without rotation) it indicated no changes of greenness index. It was investigated to better interpret how vegetation feedback modifies the sensitivity of drought indices associated with raising tendency of air temperature and changes of cold and hot year seasons length in the territory of CA.
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John, Ranjeet. "The Effects of Land cover/Land Use Change on Ecosystem Functions in Semi-arid Inner Mongolia". University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1294335117.

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White, II David Allen. "Vegetation Controls on the Dynamics and Quality of Soil Organic Carbon in an Arid, Hyperthermic Ecosystem". Thesis, The University of Arizona, 2008. http://hdl.handle.net/10150/193315.

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Arid lands comprise vast regions of terrestrial land, highlighting the importance of understanding their role in the global carbon cycle. The objective of this study was to determine the effect of Prosopis velutina (mesquite), Larrea tridentata (creosote) and a combination of Bouteloua barbata, Bouteloua aristidoides, Aristida adscensionis, and some Cynodon dactylon (mixed grass) vegetation types on soil organic carbon (SOC) dynamics and quality in an arid, hyperthermic ecosystem of southern Arizona. This was accomplished by quantifying vegetation type control over: (i) local scale SOC stocks; (ii) soil aggregate stability; (iii) SOC turnover and microbial community composition; (iv) the distribution of SOC in physically defined fractions; and (v) the thermal nature and composition of SOC. The results from this study demonstrated significant variation in SOC dynamics and quality between vegetation with potential feedbacks to SOC sequestration of atmospheric CO₂.
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Waswa, Peter Fuchaka. "Abiophysical analysis of erosion damage in a semi-arid agro-ecosystem in Kenya : towards sustainable land management /". Bonn : Inst. für Städtebau, Bodenordnung und Kulturtechnik, Lehrstuhl für Landwirtschaftlichen Wasserbau und Kulturtechnik, 2000. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=009329302&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.

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Libri sul tema "Arid Ecosystem"

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S, Faroda A., e Arid Zone Research Association of India., a cura di. Management of arid ecosystem. Jodhpur: Arid Zone Research Association of India and Scientific Publishers, 1999.

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1935-, Kolarkar A. S., Joshi D. C. 1943- e Sharma K. D. 1950-, a cura di. Rehabilitation of degraded arid ecosystem. Jodhpur: Scientific Publishers, 1992.

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Partnership for Arid Lands Stewardship (PALS), a cura di. Arid lands: Teacher handbook. [Richland, Wash: Partnership for Arid Lands Stewardship, 1999.

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N, Tewari D. Desert ecosystem. Dehra Dun, India: International Book Distributors, 1994.

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W, Hoekstra T., e Shachak Moshe, a cura di. Arid lands management: Toward ecological sustainability. Urbana: University of Illinois Press, 1999.

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Briggs, Mark K. Riparian ecosystem recovery in arid lands: Strategies and references. Tucson: University of Arizona Press, 1996.

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1926-, Rickard W. H., e Pacific Northwest Laboratory, a cura di. Shrub-steppe: Balance and change in a semi-arid terrestrial ecosystem. Amsterdam: Elsevier, 1988.

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Xiaoling, Pan, Zhongguo hai yang xue hui., Society of Photo-optical Instrumentation Engineers., United States. National Aeronautics and Space Administration. Earth Science Technology Office. e Guo jia yao gan zhong xin (China), a cura di. Ecosystems dynamics, ecosystem-society interactions, and remote sensing applications for semi-arid and arid land: 24-27 October 2002, Hangzhou, China. Bellingham, Wash., USA: SPIE, 2003.

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M, Edersson Cabrera. Aproximación metodológica para la delimitación de ecosistemas de enclaves secos: Caso piloto, cañones del río Dagua y del río Tulua, Valle del Cauca - Colombia. Bogotá, D.C., Colombia: Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, 2006.

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M, Edersson Cabrera. Aproximación metodológica para la delimitación de ecosistemas de enclaves secos: Caso piloto, cañones del río Dagua y del río Tulua, Valle del Cauca - Colombia. Bogotá, D.C., Colombia: Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, 2006.

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Capitoli di libri sul tema "Arid Ecosystem"

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BurnSilver, Shauna B., Jeffrey Worden e Randall B. Boone. "Processes of Fragmentation in the Amboseli Ecosystem, Southern Kajiado District, Kenya". In Fragmentation in Semi-Arid and Arid Landscapes, 225–53. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-4906-4_10.

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Overton, Ian C., e Tanya M. Doody. "The River Murray-Darling Basin: Ecosystem Response to Drought and Climate Change". In Drought in Arid and Semi-Arid Regions, 217–34. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-6636-5_12.

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Galvin, Kathleen A., Philip K. Thornton, Randall B. Boone e Linda M. Knapp. "Ngorongoro Conservation Area, Tanzania: Fragmentation of a Unique Region of the Greater Serengeti Ecosystem". In Fragmentation in Semi-Arid and Arid Landscapes, 255–79. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-4906-4_11.

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Pisanty, Irene, Cristina Pérez y Sosa e Gabriel Gálvez. "Agriculture, Water Mismanagement and Ecosystem Transformations in the Cuatrociénegas Valley in the Chihuahuan Desert, Mexico". In Drought in Arid and Semi-Arid Regions, 199–216. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-6636-5_11.

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Mahatma, Lalit, Jitendar Kumar Sharma, Harshal P. Patel, Nitin M. Patel e Rupal P. Patel. "Diversity of PGPM and Ecosystem Services". In Plant Growth Promoting Microorganisms of Arid Region, 93–124. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-4124-5_5.

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del Campo, Antonio D., M. González-Sanchis, A. Lidón, A. García-Prats, C. Lull, I. Bautista, G. Ruíz-Pérez e F. Francés. "Ecohydrological-Based Forest Management in Semi-arid Climate". In Ecosystem Services of Headwater Catchments, 45–57. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-57946-7_6.

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Oñatibia, Gastón R. "Grazing Management and Provision of Ecosystem Services in Patagonian Arid Rangelands". In Ecosystem Services in Patagonia, 47–74. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-69166-0_3.

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Huntley, Brian John. "Ecosystem Processes and Dynamics in Mesic Savannas". In Ecology of Angola, 215–47. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-18923-4_10.

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AbstractAn introduction is presented to systems ecology, through models of the pathways, pools and fluxes of materials in terrestrial ecosystems, and the role of feedback mechanisms, and of the first and second laws of thermodynamics. Food chains, food webs and trophic levels provide structure to ecosystem processes. The importance of the C4 photosynthetic pathway of the tropical grasses that dominate mesic and arid savanna biomes is emphasised. Details of the production, consumption and decomposition processes revealed in studies of mesic savanna in southern, central and western Africa illustrate the dynamics of carbon through terrestrial ecosystems. At landscape scale, the dynamics of the savanna/forest interface, that characterise much of northern Angola, is discussed in terms of tree-grass interactions and the existence of alternative stable states determined by fire.
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Boyero, Luciano, Leonardo Datri, Micaela Lopez, Clara Rodríguez Morata, Mario Robertazzi, Hernán Lopez, Maira Kraser, Tamara Canay, Juan Valle Robles e Silvia Matteucci. "Urban Planning in Arid Northern Patagonia Cities to Maximize Local Ecosystem Services Provision". In Ecosystem Services in Patagonia, 349–77. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-69166-0_17.

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Wang, Yanfen, Yali Liu, Liwen Shan, Jianqing Du, Yuexian Liu, Tong Li e Xiaoyong Cui. "Ecosystem Management and Sustainable Livelihoods in Drylands". In Dryland Social-Ecological Systems in Changing Environments, 139–57. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-9375-8_5.

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AbstractDrylands are very vulnerable ecosystems because of their resource constraints and environmental pressures etc. They are sensitive to a range of pressures, including climate change and human disturbance in many forms. The livelihoods of people in dryland regions must be made sustainable if the stability of dryland social-ecological systems is to be maintained. Human livelihoods in drylands are characterised by a single structure, great dependence on natural resources, and vulnerability to disruption by disturbance. In the context of global climate change and the associated expansion of arid biomes, livelihoods in drylands face growing challenges. Maintaining and rebuilding sustainable livelihoods are inseparable from good ecosystem management. However, ecosystem management is recognised as a “wicked problem” without clear-cut solutions because of the complexities involved. This chapter identifies the issues and challenges facing human livelihoods in drylands and proposes a research framework for dryland ecosystem management and sustainable livelihoods. The framework clarifies the core characteristics of sustainable livelihoods and the principles and strategies of ecosystem management while proposing a research philosophy to guide future enquiry.
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Atti di convegni sul tema "Arid Ecosystem"

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Moglia, A., L. Bracco, M. Chiolo e M. Buffagni. "E&P Operations in Water Stressed Areas: An Approach to the Identification, Selection and Implementation of Initiatives for a Sustainable Water Management, Withdrawal Reduction and Water Valorization". In SPE International Health, Safety, Environment and Sustainability Conference and Exhibition. SPE, 2024. http://dx.doi.org/10.2118/220301-ms.

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Water is one of earth's most critical resources, and water scarcity represents an increasing problem worldwide. Demographic growth and economic development are putting unprecedented pressure on water resources, especially in arid regions. Water is crucial for many sectors, and it is also fundamental to meet personal and household needs, for energy and industrial production, to maintain important water-dependent ecosystems and ecosystem services. Water plays a key role in all the phases of the Oil and Gas business, because of the large amounts of this resource that should be managed, both with respect to withdrawals and to disposal. For these reasons, it is essential to adopt a well-defined and sound approach in order to protect the water resource, also considering that often Oil and Gas activities take place in arid regions. All these aspects require an integrated and inclusive approach, able to build resilience against worsening factors.
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Zhao, Xin, Jia Jin, Haiying Guan e Sinan Zhang. "Spatial pattern of soil microbial biomass in a typical arid ecosystem". In International Conference on Environment and Sustainability. Southampton, UK: WIT Press, 2014. http://dx.doi.org/10.2495/ices140441.

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Dan Luo e Nai'ang Wang. "Notice of Retraction: Simulations for vegetation cover in an arid ecosystem". In 2010 International Conference on Computer Application and System Modeling (ICCASM 2010). IEEE, 2010. http://dx.doi.org/10.1109/iccasm.2010.5620721.

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Chabrillat, Sabine, Hermann J. Kaufmann, Alicia Palacios-Orueta, Paula Escribano e Andreas Mueller. "Development of land degradation spectral indices in a semi-arid Mediterranean ecosystem". In Remote Sensing, a cura di Manfred Ehlers, Francesco Posa, Hermann J. Kaufmann, Ulrich Michel e Giacomo De Carolis. SPIE, 2004. http://dx.doi.org/10.1117/12.565252.

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Gunkel, G., D. Lima, F. Selge, M. Sobral e S. Calado. "Aquatic ecosystem services of reservoirs in semi-arid areas: sustainability and reservoir management". In RIVER BASIN MANAGEMENT 2015. Southampton, UK: WIT Press, 2015. http://dx.doi.org/10.2495/rm150171.

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Mougin, Eric, D. Lo Seen, Pierre L. Frison e S. Rambal. "Assessing the complementarity of microwave and optical data for ecosystem modeling in arid regions". In Satellite Remote Sensing, a cura di Eric Mougin, K. Jon Ranson e James A. Smith. SPIE, 1995. http://dx.doi.org/10.1117/12.200761.

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Chang, Shunli, e Qingdong Shi. "Net ecosystem production in the arid land in northwest China from 1982 to 2001". In Second International Conference on Earth Observation for Global Changes, a cura di Xianfeng Zhang, Jonathan Li, Guoxiang Liu e Xiaojun Yang. SPIE, 2009. http://dx.doi.org/10.1117/12.836463.

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Tang, Cuiwen, Duning Xiao, Zhongming Zhang e Guojing Yang. "Comparative research on the landscape patterns of the arid mountain ecosystem in Northwestern China". In Remote Sensing, a cura di Manfred Ehlers e Ulrich Michel. SPIE, 2006. http://dx.doi.org/10.1117/12.689361.

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Han, Hongling. "A review of research on ecosystem of arid area using RS-GIS in China". In Geoinformatics 2007, a cura di Jingming Chen e Yingxia Pu. SPIE, 2007. http://dx.doi.org/10.1117/12.761873.

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Lipka, Oksana, G. Mazmaniants, Maria Isupova, A. Aleynikov, Dmitry Zamolodchikov e Vladimir Kaganov. "USING OF THE ILI RIVER DELTA ECOSYSTEM SERVICES FOR ADAPTATION TO CLIMATE CHANGE". In Land Degradation and Desertification: Problems of Sustainable Land Management and Adaptation. LLC MAKS Press, 2020. http://dx.doi.org/10.29003/m1700.978-5-317-06490-7/158-165.

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Ecosystem-based adaptation can be applied as an option for sustainable land management. Methodologies that not only prevent land degradation but also contribute to the maintenance of a hydrological regime have become a priority in arid Central Asian climate. Large river deltas can be used as a natural counter-regulator, which accumulates water in wet seasons/years and gradually gives it back to low-water ones. To do so the land-use regime must prevent the degradation of ecosystems and the reduction of their functions. The hystorical anthropogenic damage must be eliminated. In the case of the Ili River delta the restoration of tugai forests is required on an area of at least 30% of the territory, i.e. more than 200 thousand hectares. Afforestation can lead to an increase in the underground water supply of the river at 30 - 70%. The groundwater supply to the river branches in the delta can increase by 1.26 - 2.94 km3/year (up to 21% annual river flow), which, in turn, will lead to additional water supply to Lake Balkhash and reduce the risk of the Aral Sea crisis repetition.
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Rapporti di organizzazioni sul tema "Arid Ecosystem"

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Fischer, Richard A. Ecosystem Management and Restoration. January 2003. Riparian Restoration and Management Needs in the Arid and Semi-Arid Western United States. Fort Belvoir, VA: Defense Technical Information Center, gennaio 2003. http://dx.doi.org/10.21236/ada410913.

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Juy-abad, Fatemeh Khani, Parisa Mohammadi e Mahbubeh Zarrabi. The Identification of Some Phototrophic Microorganisms from a Semi-arid Ecosystem in Iran. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, dicembre 2018. http://dx.doi.org/10.7546/crabs.2018.12.06.

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Peters, Jan. Plant diversity patterns at different spatial scales in a semi-arid savanna ecosystem in central Namibia. BEE-Press, ottobre 2010. http://dx.doi.org/10.7809/thesis.diplom.003.

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Raymond, Kara, Laura Palacios, Cheryl McIntyre e Evan Gwilliam. Status of climate and water resources at Chiricahua National Monument, Coronado National Memorial, and Fort Bowie National Historic Site: Water year 2019. National Park Service, maggio 2022. http://dx.doi.org/10.36967/nrr-2293370.

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Abstract (sommario):
Climate and hydrology are major drivers of ecosystems. They dramatically shape ecosystem structure and function, particularly in arid and semi-arid ecosystems. Understanding changes in climate, groundwater, and water quality and quantity is central to assessing the condition of park biota and key cultural resources. The Sonoran Desert Network collects data on climate, groundwater, and surface water at 11 National Park Service units in southern Arizona and New Mexico. This report provides an integrated look at climate, groundwater, and springs conditions at Chiricahua National Monument (NM), Coronado National Memorial (NMem), and Fort Bowie National Historic Site (NHS) during water year (WY) 2019 (October 2018–September 2019). Overall annual precipitation at Chiricahua NM and Coronado NMem in WY2019 was approximately the same as the normals for 1981–2010. (The weather station at Fort Bowie NHS had missing values on 275 days, so data were not presented for that park.) Fall and winter rains were greater than normal. The monsoon season was generally weaker than normal, but storm events related to Hurricane Lorena led to increased late-season rain in September. Mean monthly maximum temperatures were generally cooler than normal at Chiricahua, whereas mean monthly minimum temperatures were warmer than normal. Temperatures at Coronado were more variable relative to normal. The reconnaissance drought index (RDI) indicated that Chiricahua NM was slightly wetter than normal. (The WY2019 RDI could not be calculated for Coronado NMem due to missing data.) The five-year moving mean of annual precipitation showed both park units were experiencing a minor multi-year precipitation deficit relative to the 39-year average. Mean groundwater levels in WY2019 increased at Fort Bowie NHS, and at two of three wells monitored at Chiricahua NM, compared to WY2018. Levels in the third well at Chiricahua slightly decreased. By contrast, water levels declined in five of six wells at Coronado NMem over the same period, with the sixth well showing a slight increase over WY2018. Over the monitoring record (2007–present), groundwater levels at Chiricahua have been fairly stable, with seasonal variability likely caused by transpiration losses and recharge from runoff events in Bonita Creek. At Fort Bowie’s WSW-2, mean groundwater level was also relatively stable from 2004 to 2019, excluding temporary drops due to routine pumping. At Coronado, four of the six wells demonstrated increases (+0.30 to 11.65 ft) in water level compared to the earliest available measurements. Only WSW-2 and Baumkirchner #3 have shown net declines (-17.31 and -3.80 feet, respectively) at that park. Springs were monitored at nine sites in WY2019 (four sites at Chiricahua NM; three at Coronado NMem, and two at Fort Bowie NHS). Most springs had relatively few indications of anthropogenic or natural disturbance. Anthropogenic disturbance included modifications to flow, such as dams, berms, or spring boxes. Examples of natural disturbance included game trails, scat, or evidence of flooding. Crews observed 0–6 facultative/obligate wetland plant taxa and 0–3 invasive non-native species at each spring. Across the springs, crews observed six non-native plant species: common mullein (Verbascum thapsus), spiny sowthistle (Sonchus asper), common sowthistle (Sonchus oleraceus), Lehmann lovegrass (Eragrostis lehmanniana), rabbitsfoot grass (Polypogon monspeliensis), and red brome (Bromus rubens). Baseline data on water quality and water chemistry were collected at all nine sites. It is likely that that all nine springs had surface water for at least some part of WY2019, though temperature sensors failed at two sites. The seven sites with continuous sensor data had water present for most of the year. Discharge was measured at eight sites and ranged from < 1 L/minute to 16.5 L/minute.
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Raymond, Kara, Laura Palacios, Cheryl McIntyre e Evan Gwilliam. Status of climate and water resources at Saguaro National Park: Water year 2019. A cura di Alice Wondrak Biel. National Park Service, dicembre 2021. http://dx.doi.org/10.36967/nrr-2288717.

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Abstract (sommario):
Climate and hydrology are major drivers of ecosystems. They dramatically shape ecosystem structure and function, particularly in arid and semi-arid ecosystems. Understanding changes in climate, groundwater, and water quality and quantity is central to assessing the condition of park biota and key cultural resources. The Sonoran Desert Network collects data on climate, groundwater, and surface water at 11 National Park Service units in south-ern Arizona and New Mexico. This report provides an integrated look at climate, groundwater, and springs conditions at Saguaro National Park (NP) during water year 2019 (October 2018–September 2019). Annual rainfall in the Rincon Mountain District was 27.36" (69.49 cm) at the Mica Mountain RAWS station and 12.89" (32.74 cm) at the Desert Research Learning Center Davis station. February was the wettest month, accounting for nearly one-quarter of the annual rainfall at both stations. Each station recorded extreme precipitation events (>1") on three days. Mean monthly maximum and minimum air temperatures were 25.6°F (-3.6°C) and 78.1°F (25.6°C), respectively, at the Mica Mountain station, and 37.7°F (3.2°C) and 102.3°F (39.1°C), respectively, at the Desert Research Learning Center station. Overall temperatures in WY2019 were cooler than the mean for the entire record. The reconnaissance drought index for the Mica Mountain station indicated wetter conditions than average in WY2019. Both of the park’s NOAA COOP stations (one in each district) had large data gaps, partially due to the 35-day federal government shutdown in December and January. For this reason, climate conditions for the Tucson Mountain District are not reported. The mean groundwater level at well WSW-1 in WY2019 was higher than the mean for WY2018. The water level has generally been increasing since 2005, reflecting the continued aquifer recovery since the Central Avra Valley Storage and Recovery Project came online, recharging Central Arizona Project water. Water levels at the Red Hills well generally de-clined starting in fall WY2019, continuing through spring. Monsoon storms led to rapid water level increases. Peak water level occurred on September 18. The Madrona Pack Base well water level in WY2019 remained above 10 feet (3.05 m) below measuring point (bmp) in the fall and winter, followed by a steep decline starting in May and continuing until the end of September, when the water level rebounded following a three-day rain event. The high-est water level was recorded on February 15. Median water levels in the wells in the middle reach of Rincon Creek in WY2019 were higher than the medians for WY2018 (+0.18–0.68 ft/0.05–0.21 m), but still generally lower than 6.6 feet (2 m) bgs, the mean depth-to-water required to sustain juvenile cottonwood and willow trees. RC-7 was dry in June–September, and RC-4 was dry in only September. RC-5, RC-6 and Well 633106 did not go dry, and varied approximately 3–4 feet (1 m). Eleven springs were monitored in the Rincon Mountain District in WY2019. Most springs had relatively few indications of anthropogenic or natural disturbance. Anthropogenic disturbance included spring boxes or other modifications to flow. Examples of natural disturbance included game trails and scat. In addition, several sites exhibited slight disturbance from fires (e.g., burned woody debris and adjacent fire-scarred trees) and evidence of high-flow events. Crews observed 1–7 taxa of facultative/obligate wetland plants and 0–3 invasive non-native species at each spring. Across the springs, crews observed four non-native plant species: rose natal grass (Melinis repens), Kentucky bluegrass (Poa pratensis), crimson fountaingrass (Cenchrus setaceus), and red brome (Bromus rubens). Baseline data on water quality and chemistry were collected at all springs. It is likely that that all springs had surface water for at least some part of WY2019. However, temperature sensors to estimate surface water persistence failed...
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Raymond, Kara, Laura Palacios e Evan Gwilliam. Status of climate and water resources at Big Bend National Park: Water year 2019. A cura di Tani Hubbard. National Park Service, settembre 2022. http://dx.doi.org/10.36967/2294267.

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Climate and hydrology are major drivers of ecosystem structure and function, particularly in arid and semi-arid ecosystems. Understanding changes in climate, groundwater, streamflow, and water quality is central to assessing the condition of park resources. This report combines data collected on climate, groundwater, and springs at Big Bend National Park (NP) to provide an integrated look at climate and water conditions during water year (WY) 2019 (October 2018–September 2019). However, this report does not address the Rio Grande or its tributaries. Annual precipitation was higher than normal (1981–2010) for Big Bend NP at four of the five National Oceanic and Atmospheric Administration Cooperative Observer Program weather stations: 111% of normal for Chisos Basin, 122% of normal for Panther Junction, 155% of normal for Persimmon Gap, and 124% of normal for Rio Grande Village. Castolon had 88% of normal annual precipitation. All five stations had higher than normal rainfall in October and December, while rainfall totals were substantially below normal at all stations in November, February, and March. Monthly precipitation totals for April through September were more variable from station to station. Mean monthly maximum air temperatures were below normal in the fall months, with Panther Junction as much as 7.5°F below normal in October. Monthly temperatures from January through July were more variable. Temperatures in August and September were warmer than normal at every station, up to +9.4°F at Rio Grande Village and +8.7°F at Chisos Basin in July. The reconnaissance drought index values indicate generally wetter conditions (based on precipitation and evaporative demand) at Chisos Basin since WY2016 and at Panther Junction and Persimmon Gap since WY2015, except for WY2017. This report presents the manual and automatic groundwater monitoring results at nine wells. Five wells had their highest water level in or just before WY2019: Panther Junction #10 peaked at 99.94 ft below ground surface (bgs) in September 2018, Contractor’s Well peaked at 31.43 ft bgs in November 2018, T-3 peaked at 65.39 ft bgs in December 2018, K-Bar #6 Observation Well peaked at 77.78 ft bgs in February 2019, and K-Bar #7 Observation Well peaked at 43.18 ft bgs in February 2019. This was likely in response to above normal rainfall in the later summer and fall 2018. The other monitoring wells did not directly track within-season precipitation. The last measurement at Gallery Well in WY2019 was 18.60 ft bgs. Gallery Well is located 120 feet from the river and closely tracked the Rio Grande stage, generally increasing in late summer or early fall following higher flow events. Water levels in Gambusia Well were consistently very shallow, though the manual well measurement collected in April was 4.25 ft bgs—relatively high for the monitoring record—and occurred outside the normal peak period of later summer and early fall. The last manual measurement taken at TH-10 in WY2019 was 34.80 ft bgs, only 0.45 ft higher than the earliest measurement in 1967, consistent with the lack of directional change in groundwater at this location, and apparently decoupled from within-season precipitation patterns. The last water level reading in WY2019 at Oak Springs #1 was 59.91 ft bgs, indicating an overall decrease of 26.08 ft since the well was dug in 1989. The Southwest Network Collaboration (SWNC) collects data on sentinel springs annually in the late winter and early spring following the network springs monitoring protocol. In WY2019, 18 sentinel site springs were visited at Big Bend NP (February 21, 2019–March 09, 2019). Most springs had relatively few indications of natural and anthropogenic disturbances. Natural disturbances included recent flooding, drying, and wildlife use. Anthropogenic disturbances included flow modifications (e.g., springboxes), hiking trails, and contemporary human use. Crews observed one to seven facultative/obligate wetland plant...
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Sharp, Jonathan. Final Report: Mechanistic and predictive understanding of needle litter decay in semi-arid mountain ecosystems experiencing unprecedented vegetation mortality. Office of Scientific and Technical Information (OSTI), agosto 2020. http://dx.doi.org/10.2172/1712688.

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Menuz, Diane, e Rebekah Downard. Opportunity for Improved Wetland Mitigation in Utah - In-Lieu Fee Mitigation Potential in Utah. Utah Geological Survey, settembre 2023. http://dx.doi.org/10.34191/ofr-756.

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Wetlands play a crucial role in watersheds and provide critical ecosystem functions, most notably, water quality improvement, fish and wildlife habitat, flood attenuation, drought mitigation, and carbon sequestration. Wetlands in Utah are regulated primarily by the federal government under the Clean Water Act (CWA), which requires mitigation to replace ecological services that are lost to permitted activities. Utah House Bill 118 (2022) directed the Utah Geological Survey to explore the potential for an In-Lieu Fee (ILF) mitigation program to improve wetland resources in Utah. An ILF program would allow entities seeking CWA permits to pay a fee to mitigate impacts to streams and wetlands rather than having to develop their own mitigation plans. To research the possible consequences of an ILF, we conducted document research and interviews with mitigation practitioners and wetland stakeholders and analyzed ten years of permit data. Interview participants agreed that an ILF would improve the quality of wetland mitigation projects, which currently are often small, isolated, and overrun with weeds. An ILF would also improve coordination between the various entities involved in natural resource protection, permitting, and restoration. Further, permittees would benefit from an ILF because it would streamline the permitting process. Research and input from current practitioners showcased that there were many options for running an ILF program that can work for Utah, which has few permitted wetland impacts compared to other, less arid states. The most effective way to build an ILF in Utah is to support a full-time ILF administrator to establish the program and develop and maintain strong relationships with regulators, restoration specialists, and those seeking permits. Based on historical permit rates, such a position could be funded by program fees after the program is established. The future of a self-sustaining ILF program is uncertain, however, due to the recent Sackett v. Environmental Protection Agency (EPA) Supreme Court decision which limited the types of wetlands that are regulated by the federal government. The expected reduction in wetland permitting creates a more challenging environment in which to operate an ILF program because permit fees will likely no longer support a full-time ILF administrator’s salary. At the same time, ensuring high quality mitigation will be more important than ever because there will be more unpermitted and thus unmitigated wetland impacts, leading to loss in ecological functions. Given these considerations, we recommend establishing a position for a wetland mitigation and restoration coordinator who can explore multiple options to preserve and restore wetlands in Utah, coordinate among agencies, and begin to implement an ILF program at a rate and scale appropriate to the new regulatory conditions. By investing in a wetland mitigation and restoration coordinator, the state can support voluntary restoration measures to increase wetland functions while at the same time improving mitigation outcomes for permittees and projects. Together, these actions will lead to healthier, more resilient wetlands that will protect the quality of life for all Utahns.
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9

Walker, David, e Jeffrey Renfrow. Toxicological reconnaissance of Arsenal? use along the Rio Grande River through Big Bend National Park: Final report. National Park Service, 2024. http://dx.doi.org/10.36967/2302769.

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This study examined the biological response of aquatic organisms, collected in situ and from laboratory toxicity testing of water and soil to the herbicide Arsenal? primarily used to decrease the invasive species Arundo donax in the Rio Grande River through Big Bend National Park in Texas (USA). Biological, toxicological, physicochemical, and flow data were collected before, during, and after an Arsenal? treatment from 4 reference and 3 treatment sites. Significant differences existed in ecoregion 24 B-IBI scoring, and in toxicity testing of water and sediment, between treatment and reference sites. Greater toxicity, and a higher inverse relationship to B-IBI scoring, was observed in sediment samples compared to water samples. This could be due to the surfactant nonylphenol ethoxylate (NPE), added to the Arsenal? formulation rather than the active ingredient imazapyr. Care must be implemented with the results of this research due to many confounding variables that occurred during the study period including flash flooding. Although flashy hydrology is relatively common to the region, it can influence aquatic macroinvertebrate assemblage structure, function, and species richness measures with these dropping due to scour and downstream displacement within a reach during, and for some period following, flooding. Therefore, flash flooding would be expected to have some effect on aquatic macroinvertebrate assemblages and subsequent B-IBI scoring. Additionally, flooding will cause some displacement, and deposition, of sediment throughout the study area. This flooding could impact the sediment toxicity results as sediment-bound contaminants could be spread some distance from their origin. Arsenal? treatment occurred during this study near sites Treatment 1 and Treatment 2 on 5/29 and 5/31 2022 respectively. This represented an extreme condition as far as concentration of potential toxicants in the water are concerned and these relatively high concentrations would be expected to have decreased within a relatively short period of time, especially in the water. It was outside of the scope and budget of this project to obtain concentrations of imazapyr or surfactants from sediment or water. Therefore, exact doses of imazapyr or surfactant for response curves could not be obtained. No sample site exists in isolation rather, influences from one reach can significantly impact downstream areas. This is especially true for aquatic ecosystems in arid regions that often exhibit flashy hydrology. However, we believe the findings from this study provide indication of potential toxicity of some magnitude as well as provide direction for management. Decisions of whether the toxic effects of herbicide use to aquatic macroinvertebrates outweigh the beneficial effects of Arundo donax control should be carefully considered.
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