552 research outputs found

    Local environmental context drives heterogeneity of early succession dynamics in alpine glacier forefields

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    Glacier forefields have long provided ecologists with a model to study patterns of plant succession following glacier retreat. While plant-survey-based approaches applied along chronosequences provide invaluable information on plant communities, the “space-for-time” approach assumes environmental uniformity and equal ecological potential across sites and does not account for spatial variability in initial site conditions. Remote sensing provides a promising avenue for assessing plant colonization dynamics using a so-called “real-time” approach. Here, we combined 36 years of Landsat imagery with extensive field sampling along chronosequences of deglaciation for eight glacier forefields in the southwestern European Alps to investigate the heterogeneity of early plant succession dynamics. Based on the two complementary and independent approaches, we found strong variability in the time lag between deglaciation and colonization by plants and in subsequent growth rates and in the composition of early plant succession. All three parameters were highly dependent on the local environmental context, i.e., neighboring vegetation cover and energy availability linked to temperature and snowmelt gradients. Potential geomorphological disturbance did not emerge as a strong predictor of succession parameters, which is perhaps due to insufficient spatial resolution of predictor variables. Notably, the identity of pioneer plant species was highly variable, and initial plant community composition had a much stronger influence on plant assemblages than elapsed time since deglaciation. Overall, both approaches converged towards the conclusion that early plant succession is not stochastic as previous authors have suggested but rather determined by local ecological context. We discuss the importance of scale in deciphering the complexity of plant succession in glacier forefields and provide recommendations for improving botanical field surveys and using Landsat time series in glacier forefield systems. Our work demonstrates complementarity between remote sensing and field-based approaches for both understanding and predicting future patterns of plant succession in glacier forefields.</p

    Urbanised forested landscape: Urbanisation, timber extraction and forest care on the Vișeu Valley, northern Romania

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    By looking at urbanisation processes from the vantage point of the forest, and the ways in which it both constitutes our living space while having been separated from the bounded space of the urban in modern history, the thesis asks: How can we (re)imagine urbanisation beyond the limits of the urban? How can a feminine line of thinking engage with the forest beyond the capitalist-colonial paradigm and its extractive project? and How can we “think with care” (Puig de la Bellacasa 2017) towards the forest as an inhabitant of our common world, instead of perpetuating the image of the forest as a space outside the delimited boundaries of the city? Through a case study research, introducing the Vișeu Valley in northern Romania as both a site engaged in the circulation of the global timber flow, a part of what Brenner and Schmid (2014) name “planetary urbanisation”, where the extractive logging operations beginning in the late XVIIIth century have constructed it as an extractive landscape, and a more than human landscape inhabited by a multitude of beings (animal, plant, and human) the thesis argues towards the importance of forest care and indigenous knowledge in landscape management understood as a trans-generational transmission of knowledge, that is interdependent with the persistence of the landscape as such. Having a trans-scalar approach, the thesis investigates the ways in which the extractive projects of the capitalist-colonial paradigm have and still are shaping forested landscapes across the globe in order to situate the case as part of a planetary forest landscape and the contemporary debates it is engaged in. By engaging with emerging paradigms within the fields of plant communication, forestry, legal scholarship and landscape urbanism that present trees and forests as intelligent beings, and look at urbanisation as a way of inhabiting the landscape in both indigenous and modern cultures, the thesis argues towards viewing forested landscapes as more than human living spaces. Thinking urbanisation through the case of the Vișeu Valley’s urbanised forested landscape, the thesis aligns with alternate ways of viewing urbanisation as co-habitation with more than human beings, particularly those emerging from interdisciplinary research in the Amazon river basin (Tavares 2017, Heckenberger 2012) and, in light of emerging discourses on the rights of nature, proposes an expanded concept of planetary citizenship, to include non-human personhood

    Prediction of grassland biodiversity using measures of spectral variance: a meta-analytical review

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    Over the last 20 years, there has been a surge of interest in the use of reflectance data collected using satellites and aerial vehicles to monitor vegetation diversity. One methodological option to monitor these systems involves developing empirical relationships between spectral heterogeneity in space (spectral variation) and plant or habitat diversity. This approach is commonly termed the ‘Spectral Variation Hypothesis’. Although increasingly used, it is controversial and can be unreliable in some contexts. Here, we review the literature and apply three-level meta-analytical models to assess test results of the hypothesis across studies using several moderating variables, relating to the botanical and spectral sampling strategies, and the types of sites evaluated. We focus on the literature relating to grasslands, which are less well studied compared to forests and are likely to require separate treatment due to their dynamic phenology and the taxonomic complexity of their canopies over small scales. Across studies, results suggest an overall positive relationship between spectral variation and species diversity (mean correlation co-efficient = 0.36). However, high levels of both within study and between study heterogeneity was found. Whether data was collected at the leaf or canopy level had the most impact on the mean effect size, with leaf level studies displaying a stronger relationship compared to canopy level studies. We highlight the challenges facing synthesis of these kinds of experiments, the lack of studies carried out in arid or tropical systems and the need for scalable, multi-temporal assessments to resolve controversy in the field

    NDVI Analysis for Monitoring Land-Cover Evolution on Selected Deglaciated Areas in the Gran Paradiso Group (Italian Western Alps)

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    The ongoing climate warming is affecting high-elevation areas, reducing the extent and the duration of glacier and snow covers, driving a widespread greening effect on the Alpine region. The impact assessment requires therefore the integration of the geomorphological context with altitudinal and ecological features of the study areas. The proposed approach introduces chronologically-constrained zones as geomorphological evidence for selecting deglaciated areas in the alpine and non-alpine belts. In the present study, the protected and low-anthropic-impacted areas of the Gran Paradiso Group (Italian Western Alps) were analysed using Landsat NDVI time series (1984–2022 CE). The obtained results highlighted a progressive greening even at a higher altitude, albeit not ubiquitous. The detected NDVI trends showed, moreover, how the local factors trigger the greening in low-elevation areas. Spectral reflectance showed a general decrease over time, evidencing the progressive colonisation of recently deglaciated surfaces. The results improved the discrimination between different greening rates in the deglaciated areas of the Alpine regions. The geomorphological-driven approach showed significant potential to support the comprehension of these processes, especially for fast-changing areas such as the high mountain regions

    Catchment based analysis of macronutrients (nitrogen and phosphorus) and organic carbon dynamics: new modelling and participatory tools

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    Ecosystem services (ESs) are increasingly being considered in decision-making with respect to mitigating future climate impacts. To capture complex variation in spatial and temporal dynamics, ecosystem models require spatially explicit data that are often difficult to obtain for model development and validation. Citizen science allows for the participation of trained citizen volunteers in research or regulatory activities, resulting in increased data collection and increased participation of the general public in resource management. Despite the increasing experience in citizen science, these approaches have seldom been used in the modelling of provisioning ecosystem services. The development of new approaches for the analysis of long-term changes in riverine carbon, hydrological and nutrient cycles is important to identify potential alteration on the biogeochemical cycles and potential impacts on the ecosystem services provided to the local population. The Basin scale approach is useful to evaluate the pressures on river ecosystems that may be distant from the receiving watercourse, including the effects of soil or water management activities that propagate or amplify downstream. However, the lack of process-based and basin-scale models for carbon transport has limited effective basin management of organic carbon fluxes from soils, through river networks and to receiving marine waters. In the present study, were examined the temporal and spatial drivers in macronutrient (nitrogen and phosphorus) and sediment delivery, carbon storage and sequestration and water yield in a major Italian river catchment and under different NBS scenarios. Information on climate, land use, soil and river conditions, as well as future climate scenarios, were used to explore future (2050) benefits of NBS on local and basin scales, followed the national and European directives related to water quality (Directive 2000/60/EC) and habitat (Directive 92/43/EEC). It was developed and validate a spatially semi-distributed mass balance modelling approach to estimate organic carbon delivery at a sub-basin scale and which allows exploration of alternative river basin management scenarios and their impact on DOC and POC dynamics. The model is built as an open-source plugin for QGIS and can be easily integrated with other basin scale decision support models on nutrient and sediment export. Furthermore, was performed an estimation of the benefits of individual and combined NBS approaches related to river restoration and catchment reforestation. To complete the ESs overall evaluation and prioritization was developed a new method in order to attributing a weight to the best NBS scenarios based on the natural stoichiometric ratio between the elements carbon, silicon, nitrogen, phosphorus (C:Si:N:P

    Atti del XXV Convegno Nazionale di Agrometeorologia. L’Agrometeorologia per la gestione delle risorse e delle limitazioni ambientali in agricoltura

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    La razionale gestione delle risorse ambientali e naturali ha nella modellistica agrometeorologia il suo supporto di base. Del resto, le note e tristi vicende che negli ultimi giorni hanno duramente interessato i territori dell’Emilia-Romagna e delle Marche, impongono alla comunità scientifica e ai gestori del territorio un’attenta valutazione degli effetti che il cambiamento climatico ha sul territorio. Pertanto, i modelli agrometeorologici sono uno strumento essenziale per il processo gestionale e decisionale sia nell’ambito dei sistemi colturali che in quello zootecnico. Numerosi sono gli studi sui meccanismi e sulle relazioni che regolano le dinamiche ambientali e produttive del territorio stesso per descrivere le sue reali potenzialità produttive e quindi, pianificare e razionalizzare l’uso delle risorse utilizzate nel processo produttivo. La caratterizzazione meteorologica ù uno dei primi passi da intraprendere per la conoscenza di un territorio, valutando non solo l’andamento dei valori medi dei principali parametri misurati al suolo, ma soprattutto la loro variabilità spaziotemporale. AIAM 2023 ù l’appuntamento annuale tra i ricercatori e i tecnici dei servizi agrometeorologici regionali per presentare i risultati degli studi e dei progetti di ricerca per la gestione degli stress abiotici, dei mezzi di previsione e gestione delle avversità che interessano il mondo agricolo, con riferimento alle politiche di sviluppo agricolo del PSN 2023-27

    Land Use and Land Cover Mapping in a Changing World

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    It is increasingly being recognized that land use and land cover changes driven by anthropogenic pressures are impacting terrestrial and aquatic ecosystems and their services, human society, and human livelihoods and well-being. This Special Issue contains 12 original papers covering various issues related to land use and land use changes in various parts of the world (see references), with the purpose of providing a forum to exchange ideas and progress in related areas. Research topics include land use targets, dynamic modelling and mapping using satellite images, pressures from energy production, deforestation, impacts on ecosystem services, aboveground biomass evaluation, and investigations on libraries of legends and classiïŹcation systems

    Trend assessment of changing climate patterns over the major agro-climatic zones of Sindh and Punjab

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    The agriculture sector, due to its significant dependence on climate patterns and water availability, is highly vulnerable to changing climate patterns. Pakistan is an agrarian economy with 30% of its land area under cultivation and 93% of its water resources being utilized for agricultural production. Therefore, the changing climate patterns may adversely affect the agriculture and water resources of the country. This study was conducted to assess the climate variations over the major agro-climatic zones of Sindh and Punjab, which serve as an important hub for the production of major food and cash crops in Pakistan. For this purpose, the climate data of 21 stations were analyzed using the Mann–Kendall test and Sen's slope estimator method for the period 1990–2022. The results obtained from the analysis revealed that, in Sindh, the mean annual temperature rose by ~0.1 to 1.4°C, with ~0.1 to 1.2°C in cotton-wheat Sindh and 0.8 to 1.4°C in rice-other Sindh during the study period. Similarly, in Punjab, the mean annual temperature increased by ~0.1 to 1.0°C, with 0.6 to 0.9°C in cotton-wheat Punjab and 0.2 to 0.6°C in rainfed Punjab. Seasonally, warming was found to be highest during the spring season. The precipitation analysis showed a rising annual precipitation trend in Sindh (+30 to +60 mm) and Punjab (+100 to 300 mm), while the monsoon precipitation increased by ~50 to 200 mm. For winter precipitation, an upward trend was found in mixed Punjab, while the remaining stations showed a declining pattern. Conclusively, the warming temperatures as found in the analysis may result in increased irrigation requirements, soil moisture desiccation, and wilting of crops, ultimately leading to low crop yield and threatening the livelihoods of local farmers. On the other hand, the increasing precipitation may favor national agriculture in terms of less freshwater withdrawals. However, it may also result in increased rainfall-induced floods inundating the crop fields and causing water logging and soil salinization. The study outcomes comprehensively highlighted the prevailing climate trends over the important agro-climatic zones of Pakistan, which may aid in devising an effective climate change adaptation and mitigation strategy to ensure the state of water and food security in the country
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