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Forests, trees and water in arid lands: A delicate balance
Abstract
Arid land's forests and trees have an important role in land stabilization, desertification control, watershed protection as well as providing wood and non-wood products. Yet, its benefits and vitality are often jeopardized by human-caused stresses and natural hazards and they are often ignored in natural resource management policy and decision making processes. When tree planting is considered, the water balance should be assessed and its evolution should be estimated for each period of the whole life of the planted stand. Also, every desertification control program or greening activity should be considered at landscape level.
... Water stress during this critical period can lead to reduced growth, diminished health, and increased mortality rates. The research on arboriculture integrates the concept of providing newly planted trees with sufficient water to support the establishment phase [2,3,77]. ...
... Implementing an effective watering strategy for newly planted trees, especially those planted from tube stocks, is essential for mitigating transplant shock and promoting successful establishment. Deep, infrequent watering practices are recommended to encourage deeper root growth and improve drought resilience over time [77]. Additionally, the use of mulches can help retain soil moisture, reduce temperature extremes, and minimize competition from grass and weeds, further supporting the tree's establishment [77,78]. ...
... Deep, infrequent watering practices are recommended to encourage deeper root growth and improve drought resilience over time [77]. Additionally, the use of mulches can help retain soil moisture, reduce temperature extremes, and minimize competition from grass and weeds, further supporting the tree's establishment [77,78]. The provision of adequate water to newly planted trees, particularly in their first 1-2 years post-transplantation period, is critical for their survival, growth, and establishment. ...
Water scarcity inhibits plant growth, especially in arid regions. Traditional irrigation methods often lack efficiency and sustainability. This study investigates AquaTrap, a biomimetic design, as a potential solution. The study highlights AquaTrap’s advantages by analyzing its design and previous research on bioinspired water harvesting. It highlights its ability to increase water efficiency and support sustainable plant growth in dry areas. Biomimicry inspires AquaTrap’s design, which mimics natural systems to capture and deliver water to plant roots. To collect condensation while repelling water, the stack uses superhydrophobic materials. Plant roots then receive this accumulated water for growth. Compared to traditional methods, AquaTrap offers many advantages. Its stand-alone design eliminates complex infrastructure and minimizes evaporation. Additionally, delivering water directly to the roots reduces waste and increases water efficiency. This technology holds promise for introducing new vegetation, restoring plant life, and promoting sustainable agriculture in arid regions. Further research is needed to explore the potential of AquaTrap in a variety of field conditions, optimize it for different plants and environments, and evaluate its economic feasibility for widespread use. AquaTrap also has significant potential for sustainable forestry, as it can significantly increase the survival and growth of trees in water-scarce environments. System solution opportunities and modular structure provide crucial support during the most critical adaptation period of afforestation. By reducing water consumption and increasing efficiency, it supports the establishment and maintenance of healthy forests, which are vital for ecosystem resilience and biodiversity.
... These factors render arid land ecosystems extremely fragile, and anthropogenic influences, even minor deviations from the mean climate condition, can cause substantial changes in composition, productivity, or the nor-mal functioning of the systems. The ecosystem, therefore, possesses a reduced ability to buffer the effects of climatic extremes and human overexploitation with its scant resources (Malagnoux et al., 2007;Marigi et al., 2016). Both anthropogenic and climatic changes generally result in a negative impact on the ecosystem and the livelihoods of millions of people inhabiting the arid lands; and these problems are expected to exacerbate due to global climatic changes (Leech, 2013;Maestre, 2016). ...
... Leguminous trees play a crucial role under the harsh environmental conditions of arid regions (Amerin and Daldoum, 2017;Tchatchoua et al., 2019). They contribute to maintaining suitable conditions for the normal functioning of the ecosystem and safeguard human enterprises, such as arable cultivation, animal husbandry, and livelihoods (Malagnoux et al., 2007). With a high tolerance to aridity, capabilities of fixing nitrogen, and providing food, microhabitats, and shelter to various species of different organisms, these trees play a key role in the restoration of degraded arid land ecosystems (Fox et al., 2012;Smýkal et al., 2014). ...
... Silver butterfly Kargon Allah results will aid in reforestation projects in arid lands (Malagnoux et al., 2007;Asiedu et al., 2012). ...
The seed germination dynamics of Acacia nilotica, Bauhinia rufescens, Faidherbia albida, and Piliostigma reti-culatum were investigated over 28 days. Seeds were pretreated with concentrated sulfuric acid. Determined germination parameters included germination energy, germination period, germination capacity, germination inertia, and viability loss. Seeds exposed to sulfuric acid for extended periods (30, 40, 50, and 60 min) exhibited a higher germination rate (α = 0.05). For A. nilotica seeds, the 50 min acid treatment resulted in the highest germination energy of 85.5% and germination capacity of 89.5% (P = 0.001); conversely, the 60-min treatment yielded the highest germination energy and capacity, both 96.5% (P = 0.079), for P. reticulatum. In the case of B. rufescens, the 30-min treatment led to the highest germination energy of 93% and germination capacity of 88% (P = 0.001). For F. albida, all acid treatments resulted in 100% for both germination energy and germination capacity (P = 0.621). Viability losses for A. nilotica and P. reticulatum were higher (32 and 30%, respectively) than those for B. rufescens and F. albida, which were 19.5 and 6%, respectively (P = 0.000). Generally, higher germination energy resulted in lower viability loss, dependent on the species. Analyses of germination inertia and viability loss suggest that seeds of A. nilotica and P. reticulatum possess a greater ability to survive in arid land climates than those of B. rufescens and F. albida. However, due to the advantage of lower viability loss, B. rufescens and F. al-bida should be preferred for the natural restoration of arid land ecosystems where seed availability is a major concern.
... Whereas there is still a considerable research background on forest decline within tropical forests (e.g., Hoekman et al., 2020), temperate forests (e.g., Sáenz-Romero et al., 2020), and boreal forests (e.g., Kuuluvainen et al., 2021;Sánchez-Pinillos et al., 2021), there is a noticeable dearth of attention paid to the forest decline in arid and semi-arid regions (e.g., Ghasemi et al., 2023;le Polain de Waroux et al., 2012). It is, therefore, essential to map, and understand the forest decline for better forest management, particularly in arid and semi-arid regions with fragile ecosystems (Andrews et al., 2020;Anderegg et al., 2012) with periodic droughts, extreme heat, and overexploitation of scarce resources (i.e., water) (Malagnoux et al., 2007). ...
... In line with the above stated, forest decline in arid and semi-arid ecosystems presents significant ecological and environmental challenges due to the unique challenges faced by these regions, including water scarcity, fragile ecosystems, local livelihoods closely depending on the forest, and unique biodiversity (Andrews et al., 2020;Malagnoux et al., 2007). More than one billion people residing in arid and semi-arid climates rely on these forests to provide ES (le Polain de Waroux et al., 2012), making their decline particularly significant. ...
... Climate change, habits fragmentation, degradation, overexploitation, invasive species and anthropogenic disturbances are the main forces behind plant diversity loss (Corlett, 2016;El-Wahab, 2016;Heydari et al., 2014;Heydari et al., 2017a;Liang et al., 2016;Máliš et al., 2021;Newbold, 2018). The process of semiarid and Mediterranean forest destruction, which is taking place in about six percent of the world's forests (Grainger, 1999;Malagnoux et al., 2008;De Waroux & Lambin, 2012), has been observed for a long time (e.g., Malagnoux et al., 2008;Sivakumar et al., ). For example, high grazing intensity as well as fire and land-use changes have been recognized as the main disturbance factors on forest vegetation in the Mediterranean (Heydari et al., 2017a,b;Heydari et al., 2020;Moradizadeh et al., 2020;Tálamo et al., 2012). ...
... Climate change, habits fragmentation, degradation, overexploitation, invasive species and anthropogenic disturbances are the main forces behind plant diversity loss (Corlett, 2016;El-Wahab, 2016;Heydari et al., 2014;Heydari et al., 2017a;Liang et al., 2016;Máliš et al., 2021;Newbold, 2018). The process of semiarid and Mediterranean forest destruction, which is taking place in about six percent of the world's forests (Grainger, 1999;Malagnoux et al., 2008;De Waroux & Lambin, 2012), has been observed for a long time (e.g., Malagnoux et al., 2008;Sivakumar et al., ). For example, high grazing intensity as well as fire and land-use changes have been recognized as the main disturbance factors on forest vegetation in the Mediterranean (Heydari et al., 2017a,b;Heydari et al., 2020;Moradizadeh et al., 2020;Tálamo et al., 2012). ...
Additive partitioning of species diversity is a valuable approach for quantifying the spatial patterns of biodiversity sampled in hierarchically scaled studies. This approach may provide key insights into vegetation community restoration following terrestrial ecosystems degradation in different climatic conditions. The scale-dependence of plant diversity in relation to different plant functional groups (e.g., herbaceous and woody) is still little understood. This research aims to investigate the influence of management options (protected vs. non-protected) and climatic conditions (semi-arid vs. Mediterranean) on different components of diversity in both herbaceous and woody species derived from local and regional scales (i.e., plot and site, respectively). In the studied areas, a total of 64 plots (1000 m2 ) in local scale and 128 micro-plots (1m2) among 16 sites in regional scale were selected for sampling the woody and herbaceous species data, respectively, by using a hierarchical sampling design. Diversity components of local (α1, β1) and regional (α2, β2) scales were extracted according to additive partitioning method. Differences in diversity component (α1, α21, β1 and β2) and floristic composition between management options and climatic conditions were evaluated using GLMM and DCA. The results indicate that all components of total species (both herbaceous and woody) diversity (α1, α2, β1 and β2) were significantly influenced by management options (P < 0.05) with greater values in the protected areas than the non-protected areas. However, the climatic conditions only had significant effects on β2, with greater values in the Mediterranean compared to semi-arid areas. Moreover, the separate analysis of herbaceous and woody species indicated that management options have a greater significant effect on different diversity components compared to the climatic condition. Detrended correspondence analysis (DCA) showed that floristic variations along the axes are strongly affected by management in both climatic conditions. This indicates that protection measures mostly increased plant species diversity at the local and regional scales, which is independent of the climatic condition.
... Arid and semi-arid ecosystems constitute more than 30% of the Earth's terrestrial surface and are among the world's most fragile ecosystems due to periodic droughts and increasing overexploitation of the limited water resources (Malagnoux et al., 2007). ...
... Moreover, these ecosystems are facing extraordinary challenges, including desertification, biodiversity loss, poverty and climate change (FAO, 2015). To tackle such challenges, large-scale afforestation and reforestation efforts have been implemented in these regions to convert farm-, grass-and shrub-land into forest plantations (Cao et al., 2011;Malagnoux et al., 2007;FAO, 2015;Sadeghi et al., 2016) because trees and forests are vital for averting desertification and increasing the resilience of ecosystems in the face of global change. Such restoration measures, however, have raised concerns about the effects of the new forest plantations on water resources (Farley et al., 2005;Wang et al., 2008) because canopies of plantations may reduce water yield from watersheds through transpiration, interception and evaporation (Farley et al., 2005), creating potentially conflicting demands for water between ecosystems and humans (Feng et al., 2016). ...
Interception loss can remove a significant portion of rainwater from forested ecosystems. Therefore, the quantification and modelling of interception loss are of significant importance if human and ecosystem water demands are to be balanced under a future changing climate. This is particularly true for semi-arid/arid regions, where afforestation has become an important ecological restoration measure to tackle desertification, poverty and climate change. However, quantification and modelling of interception loss of plantations in these regions have rarely been reported. In the present study, rainfall interception loss was quantified and modelled over a one-year period (January-December 2016) for a deciduous broad-leafed R. pseudoacacia plantation and an evergreen needle-leaf P. tabuliformis plantation (common afforestation tree species) situated in the semi-arid Loess Plateau of China. The stand age, density, canopy cover and leaf area index of R. pseudoacacia during the study period were 15 years, 2000 tree ha⁻¹, 0.48 and 1.41 m² m⁻², respectively. The corresponding values for Pinus tabuliformis were 17 years, 1200 tree ha⁻¹, 0.62 and 2.53 m² m⁻². The measured throughfall, stemflow and derived estimates of interception loss for R. pseudoacacia were 81.1%, 1.3% and 17.6%, respectively. The corresponding values for P. tabuliformis were 75.4%, 0.7% and 23.9%. Given that the weather conditions experienced by the two forest stands were similar, the observed higher interception loss for P. tabuliformis can be explained by the higher canopy storage capacity and wet canopy evaporation rate of this species. The revised Gash analytical model of rainfall interception was well calibrated and validated against field measurements and was able to simulate the cumulative interception loss at two forest stands accurately, and it also effectively captured the seasonal variation (leafed growing and leafless dormant seasons), provided that the optimized wet-canopy evaporation rates were used. The revised model was highly sensitive to the canopy storage capacity and changes in the ratio of mean wet canopy evaporation to mean rainfall intensity and less sensitive to canopy cover, but it was found to be fairly insensitive to the trunk storage capacity.
... In line with this study Zhao et al. (2018) found that precipitation variables contribute more in species distribution than temperature variables. This high contribution of precipitation variables to the R. prinoides predicted distribution was understandable as water availability was the main factor limiting natural distribution of plants in arid and semi-arid ecosystems and it depends heavily on rainfall (Malagnoux et al., 2008). In addition, changes in precipitation affect the growing season of plant growth and primary productivity Zhang et al., 2015). ...
Nowadays, the crucial issue in ecology is how changing climate influences species distributions and existence in a natural ecosystem. Changes in spatiotemporal environmental patterns lead to either expansions, contrasts, or shifts to comparable habitats. The aim of this study was to define the ecological niches, potential distributions and examine trends of changes in Rhamnus prinoides in response to climate change. A bioclimatic, topographic, and soil type dataset were used to analyze the current and future species distribution patterns. The model, with a high accuracy (AUC 0.887, TSS 0.6327), revealed that elevation and soil type are key factors influencing R. prinoides distribution. Under the current climatic conditions, the predicted total suitable habitat of R. prinoides was approximately 15.17% of Tigray. Future climate scenarios predict both expansion and contraction of these areas, particularly in the northwest, central, and southern zones. In addition, areas of new and lost habitat for R. prinoides species were found in all scenarios. Findings of this study concluded that, the distributional range of R. prinoides was found to be primarily associated with altitude and soil type. Moreover, the majority of Tigray's highlands will continue suitable potential areas for R. prinoides cultivation in the future. ARTICLE HISTORY
... These trees play a pivotal role in land stabilization, combating desertification, safeguarding watersheds, and contributing to wood and economic production (Brandt et al. 2020). Their importance is particularly pronounced in semi-arid and arid territories, which span a third of the world's landmass and sustain approximately one billion inhabitants (Malagnoux et al. 2007;Xia et al. 2021). However, commonly used forest structure descriptors such as canopy cover and plot-level leaf area index are not suitable to characterize isolated trees. ...
... Desertification is the most serious environmental problem in arid regions (Malagnoux et al. 2007;Yu et al. 2017). Annually, desert expansion has caused great economic loss worldwide (Nash 1999;Touheti et al. 2013;. ...
Background Desertification is the most severe environmental problem in arid and semi-arid regions and has caused great economic loss every year. However, artificial sand fixation barriers function on sand fixation for only 10-20 years. Searching for a native species with long-term sand fixation effect and strong environmental adaptive capacity, and low water consumption is needed. In this study, we investigated the environmental adaption and sand fixation effect of a grass from Poaceae family (Psammochloa villosa) that is indigenous to the desert of Northwest China. Results The results showed that P. villosa has a streamlined leaf form, strong mechanical strength, and flexibility to adapt to wind. Leaf curling of P. villosa under drought decreased water loss rate through decreased evaporation area to adapt to drought. Significant negative relationship between adventitious root length and horizontal root burial depth indicates that adventitious roots help P. villosa absorb water and nutrients from soil under shallow sand burial condition, which enables P. villosa to adapt to different sand burial conditions. P. villosa fixed sand dunes through the distribution of the population at the top of the dune and the vertical relationship between the direction of windblown sand and the direction of growth of P. villosa, which stopped the expansion of the dune. Conclusions Growth characteristics of wind and drought tolerant leaf traits and adventitious roots under sand burial indicate that P. villosa is well adapted to dry sandy desert conditions and burial by sand. The distribution of the P. villosa population on the sand dune is a "brake" on its expansion. These findings provide new insight for active sand dune fixation and desertification control using native grass in the desertified regions.
... Over 33% of the earth is an arid or semi-arid territory, hosting nearly one billion people (Malagnoux et al. 2007) and 1% of the world's freshwater resources (Qadir and Sato 2016). By definition, in arid and semi-arid regions, water supplies are limited due to little rainfall and elevated evaporation (Heyns 2009), putting more pressure on water resources. ...
Water is a critical resource for human life and plays a vital role in energy production. Energy is equally essential in water supplies but generates carbon emissions to the atmosphere depending on the energy source. Appraising water, energy, and carbon nexus is essential for promoting sustainable drinking water systems (DWSs) in the case of small- and medium-sized utilities, representing a significant portion of the water supply in many countries. Smaller utilities face unique challenges, such as insufficient funding, aging infrastructure, and higher operational costs. This paper examines over 100 studies to identify and comprehensively understand how source type and location, raw water quality, water consumption patterns, system size, land use, population density, topography, infrastructure age, and system losses and maintenance impact energy consumption in small and medium DWSs. The review also identified more than 40 indicators related to energy and carbon from the literature, providing advanced information in this area. Findings suggest a gap in understanding how energy and carbon indicators relate to the utility's operational performance. By analyzing the challenges and opportunities smaller utilities face in optimizing water, energy, and carbon nexus, this paper highlights the necessity of shifting towards cleaner energy sources to mitigate the environmental impacts. It also emphasizes the importance of adopting a holistic approach that integrates technological advancements, regulatory guidelines, and active community engagement to achieve decarbonization in DWSs. The present study aims to inform policymakers, water management professionals, and broader stakeholders about the essential components of sustainable and resilient small and medium DWSs.
... Other evidence shows sharp variations of SUHI intensity across NDVI gradients ( Figure S6), indicating the implementation of more effective tree planting and irrigation in urban environments could offer an immediate way to mitigate urban-induced warming related to urban population exposure. 57 However, alleviating warming and available water resources are closely coupled (synchronous occurrence) in arid cities, 58 requiring strong trade-offs to be resolved, 31 as water scarcity would be exacerbated as a result of future climate changes. 59 Urban-rural gradient models on urbanization effects are utilized extensively in recent years. ...
Increasing urbanization exacerbates surface energy balance perturbations and the health risks of climate warming; however, it has not been determined whether urban-induced warming and attributions vary from local, regional, to global scale. Here, the local surface urban heat island (SUHI) is evidenced to manifest with an annual daily mean intensity of 0.99℃–1.10℃ during 2003–2018 using satellite observations over 536 cities worldwide. Spatiotemporal patterns and mechanisms of SUHI tightly link with climatevegetation conditions, with regional warming effect reaching up to 0.015℃–0.138℃ (annual average) due to surface energy alterations. Globally, the SUHI footprint of 1,860 cities approximates to 1% of the terrestrial lands, about 1.8–2.9 times far beyond the urban impervious areas, suggesting the enlargements of the imprint of urban warming from local to global scales. With continuous development of urbanization, the implications for SUHI-added warming and scaling effects are considerably important on accelerating global warming.
... Due to deficient rainfall and increased resource overexploitation, arid and semi-arid regions are among the world's most vulnerable ecosystems. Arid and semi-arid terrain cover roughly one-third of the world's surface area and are home to approximately one billion people, most of whom are among the poorest (Malagnoux et al. 2007; Bana et al. 2022). The ecosystems of arid zone constituents, Forests, trees and grasses play an essential role in developing and maintaining suitable conditions for farming and livelihood. ...
Forests have evolved in their natural ecosystems over millennia to become the world’s most important and valuable renewable natural resources. Genetic variety in perspective trees has been defined as Forest Genetic Resources (FGRs). Forest genetic resources directly or indirectly sustain human livelihoods and provide raw materials for various forest-based enterprises. This chapter focuses on the FGRs of the arid and semiarid regions, which have a wide range of land formations, soils, fauna, plants, water balances, and human activities. Cultivating trees that have the potential to generate lucrative non-timber goods is the primary source of revenue in this problematic climatic situation. Arid and semi-arid regions have a diverse gene pool of tree species. The increased pressure and ongoing desertification threaten the gene pool of tree species in arid and semi-arid environments. These regions' FGRs are not sufficiently documented, and there is no way to access and use them effectively. This paper intends to establish a framework for writing, better understanding, protecting, and understanding the utility of non-timber forest genetic resources (NTFGR) in dry and semi-arid regions. It focuses on arid and semi-arid tree species that have the potential to yield non-timber value, to increase awareness and understanding of Forest Genetic Resources.
... Arid and semiarid ecosystems are facing severe challenges due to periodic droughts and the increasing overexploitation of meager water resources, including desertification, biodiversity loss, and poverty (Ma, Li, et al., 2019;Malagnoux et al., 2007). Considering trees and forests are crucial for preventing desertification and enhancing ecosystem resilience when faced with negative environmental changes (Ma, Wang, et al., 2019), many large-scale afforestation and reforestation measures have been implemented in water-scarce regions (e.g., arid Yiran Li and Yushi Liang are co-first authors. ...
The Grain for Green Program (GFGP) has promoted vegetation restoration and environmental improvement in the Loess Plateau (LP) and has sparked considerable interest in its effects on local hydrological cycle processes. However, few studies have examined the spatiotemporal evolution characteristics of rainfall interception (RI) and its influencing factors in the LP after GFGP implementation, even though RI directly controls the potential available water resources entering the ecosystem (Peffective) and
largely influences the changes in hydrological fluxes in water-limited regions. This study employed the remote sensing (RS)-Gash model to investigate RI and Peffective in the LP. Results showed that RI and Peffective increased at a rate of 0.7 (p < 0.01) and 2.5 mm/year (p = 0.12), respectively, during the complete implementation of the GFGP (2001–2018). Spatially, the two were dominated by significantly increasing (area share, 50.3%) and nonsignificantly increasing (74.2%) trends, respectively. The dominant drivers of the changes in RI and Peffective are vegetation factors and precipitation, respectively. The results imply that after the implementation of the GFGP, water scarcity in most areas of the LP seems to show signs of improvement, rather than worsening at source. However, people should remain alert about issues that can occur in semihumid areas, including vegetation's degradation due to excessive afforestation or
single-species plantations, particularly at the Ziwuling Mountains. The successful greening experience of the GFGP in the LP is worth promoting, but lessons should also be learned regarding its unsustainability in areas with relatively abundant water.
... It is increasingly accepted that silvicultural practices for forest restoration can enhance ecological resilience and resistance to drought and wildfire, particularly where they maintain structural heterogeneity (Churchill et al., 2013). Yet semiarid woodlands, which occupy approximately 6% of the terrestrial surface (Malagnoux et al., 2007) and occur on every continent except Antarctica, are not consistently managed in the context of maintaining or enhancing woodland health. To the contrary, in many parts of the world, concerns about expansion of semiarid woodlands have led to extensive tree and shrub removal treatments (Ding & Eldridge, 2019) that over time may contribute to drought-related woodland losses. ...
Abstract Dryland woodland ecosystems worldwide have experienced widespread drought‐ and heat‐related tree mortality events coupled with extreme wildfire behavior. In contrast to other forest types where the emphasis has been on the silvicultural enhancement of ecosystem resilience and restoration of structural heterogeneity, limited frameworks are available for management to improve drought resilience in semiarid woodlands. This challenge is especially acute in pinyon–juniper woodlands, a dominant vegetation type across western North America that has experienced extensive tree die‐off over the past several decades while simultaneously undergoing expansion in portions of its range. In this paper, we describe the critical and urgent need to manage for future drought resilience in these highly vulnerable ecosystems and synthesize the current state of knowledge on how to enhance woodland resilience to drought coupled with high temperatures and associated disturbances. We present a landscape prioritization framework for guiding management goals and practices that requires prioritization of efforts based on the need for action and the probability of a positive outcome. Four guiding factors include historical woodland structure and drivers of long‐term landscape change, current vegetation structure and composition, future climate suitability, and habitat and resource value. In summarizing the strength of evidence supporting our recommendations, we identify critical knowledge gaps and highlight the importance of adaptive management strategies that reflect current uncertainties. This will ultimately allow for improved management of diverse semiarid woodland ecosystems that are undergoing substantial changes due to past and present land use, biological invasions, and climate change.
... Arid lands have both components, i.e., abundant and diverse social values for ecosystem services. Arid lands occupy about one-third of the global land surface, being home to about one billion people (Malagnoux, S ene, and Atzmon 2007). On the one hand, the livelihood of these people is highly dependent on the ecosystem goods and services (Lu et al. 2018). ...
... It can be found in scattered stands at elevations of 1000 to 2500 m a.s.l., where its distribution is mainly in uenced by climatic and orographic traits (Camarero et al., 2021;Quézel, 1998;Slimani, 2014;). In Algeria, over the past decade, native vegetation has been removed or destroyed for various reasons, leading to a disturbance of the delicate balance between soil, vegetation, and water in natural environments (García- Ruiz et al., 2013;Malagnoux et al., 2008). This has resulted in signi cant soil loss and the disappearance of various plant species, especially in sensitive landscapes with semi-arid and arid climatic conditions due to incorrect land use with deforestation and erosion ( The aim of afforestation is not only to optimize economic and conservation values of biological diversity in wooded lands, but also to promote the intrinsic values of biological and cultural diversity in the Algerian region (Chenchouni, 2019;Djema & Messaoudène, 2009). ...
The degradation of Algerian forests caused by repeated fires, pests, diseases, and illegal cutting has led to significant losses in the natural heritage. Afforestation activities play a crucial role in restoring the degraded ecosystem, but the ecological characteristics of the forests are often overlooked when selecting single or multiple native or exotic coniferous species for afforestation. This study used a multivariate synecological approach (such as, Redundancy Canonical Analysis, a variation partitioning approach based on partial RDA and multivariate regression tree with indicator species) to analyze the relative contributions of environmental factors in forest bird community assembly in Atlas cedar stand afforestations. The survey used the point count method to observe the spatial distribution of breeding forest birds across the wooded landscape with respect to habitat predictors, summarizing woodland physiognomy and landscape-scale variables. A total of 47 forest bird species were observed, and the used multivariate synecological analysis has identified three major patterns of relationships among breeding birds and afforested area: the first was related to changes in tree structure during growth, the second was associated with the height of the grass layer, and the third was the gradient of height elevation.
... Afforestation and reforestation have been the predominant means of countering forest degradation and mitigating climate change in recent decades [1], and the global forested area increased by 123 million ha between 1990-2020 [2]. Planted forests play valuable roles in reducing losses of natural forests, combating soil erosion and desertification, and boosting poverty alleviation strategies, especially in arid and semi-arid regions, which are among the most fragile ecosystems [3]. However, ecological restoration is a continuous successive process, and afforestation managers are eager to obtain the associated environmental benefits, resulting in negative effects such as increased water scarcity, declining soil quality, and low tree survival rates [4]. ...
Large-scale afforestation in arid and semi-arid areas with fragile ecosystems for the purpose of restoring degradation and mitigating climate change has raised issues of decreased groundwater recharge and ambiguous climatic benefits. An accurate planted forest mapping method is necessary to explore the impacts of afforestation expansion on fragile ecosystems. However, distinguishing planted forests from natural forests using remote sensing technology is not a trivial task due to their strong spectral similarities, even when assisted by phenological variables. In this study, we developed an object- and shapelet-based (OASB) method for mapping the planted forests of the Ningxia Hui Autonomous Region (NHAR), China in 2020 and for tracing the planting years between 1991 and 2020. The novel method consists of two components: (1) a simple non-iterative clustering to yield homogenous objects for building an improved time series; (2) a shapelet-based classification to distinguish the planted forests from the natural forests and to estimate the planting year, by detecting the temporal characteristics representing the planting activities. The created map accurately depicted the planted forests of the NHAR in 2020, with an overall accuracy of 87.3% (Kappa = 0.82). The area of the planted forest was counted as 0.56 million ha, accounting for 67% of the total forest area. Additionally, the planting year calendar (RMSE = 2.46 years) illustrated that the establishment of the planted forests matched the implemented ecological restoration initiatives over the past decades. Overall, the OASB has great potential for mapping the planted forests in the NHAR or other arid and semi-arid regions, and the map products derived from this method are conducive to evaluating forestry eco-engineering projects and facilitating the sustainable development of forest ecosystems.
... Previous studies indicated the positive influence of tree plantation on area stabilization [14]. Therefore, the project managers consult with the local Bedouins on preferred trees and shrubs that may suit a plantation in the rehabilitated gullies that were bred in a unique nursery at Hura. ...
In the previous century, the Bedouins a nomadic people who migrated all over the Arab peninsula with their herds began to settle in villages, one of their settlement areas is the Negev highlands. While the younger generation searches for similar occupations as the surrounding urbanized Israelis, the adult ones in many cases sustain their traditional farming practices. In many cases these practices are not profitable and not sustainable, nevertheless , these practices are based on long-term experience in arid terms. Until recently the municipalities did not invest money and efforts to collect this knowledge and render it a sustainable and profitable one. A mission that became crucial not only due to the adults aging and the risk that this knowledge will be lost but due to the rapid transition of un-arid regions into arid or desertified ones worldwide that requires suitable farming practices. Hereby the scheme of acquiring this knowledge from the Bedouin farmers, designing sustainable and profitable solutions, managing the cultivated lands, and analyzing with them the outcome will be described together with samples from the Negev highlands. This chapter will focus on water catchment construction, which became a crucial requirement for sustainable agriculture due to the increased intensity of the rainfall event worldwide.
... In arid and semi-arid regions, large scale afforestation and reforestation activities have been carried out in order to tackle soil desertification, biodiversity loss and poverty, as trees and forests are vital for averting desertification and providing woods for local people [1,2]. For example, in dryland regions of the world,~49 billion ha of land were reforested or afforested with trees between 2000 and 2010, resulting in a 0.8% increase in forest cover [3,4]. ...
Understanding how rainfall is partitioned into throughfall, stemflow, and interception losses by xerophytic trees is important for evaluating afforestation projects and modeling hydrological budgets in semi-arid regions. However, information regarding rainfall partitioning by xerophytic trees and the controlling factors in semi-arid regions remains underrepresented in the literature. We examined whether plant functional groups have a significant impact on rainfall partitioning in two xerophytic trees (evergreen species: Pinus tabuliformis (Pinales:Pinaceae) hereafter called P. tabuliformis, deciduous species: Robinia pseudoacacia L. (Fabales:Fabaceae) hereafter called R. pseudoacacia) commonly used for afforestation on the semi-arid Loess Plateau of China, and evaluated the effects of rainfall, canopy characteristics and meteorological variables on rainfall partitioning. The event-based gross rainfall, throughfall and stemflow were measured during both growing (May–October) and dormant (January–April and November–December) seasons in 2015 and 2016 within an afforested watershed in semi-arid Loess Plateau of China. During our study period, the average rainfall depth for growing season and dormant season was 8.4 mm (varied from 0.2 to 57.6 mm) and 5.6 mm (varied from 0.2 to 41.6 mm), respectively. On average, the measured throughfall, stemflow and interception loss for R. pseudoacacia accounted for 81.8%, 1.4% and 16.8% of gross rainfall, respectively. Corresponding values for P. tabuliformis were 75.1%, 0.7% and 24.1%, respectively. Significant differences (p < 0.05) in stemflow were detected between R. pseudoacacia and P. tabuliformis during both the growing and dormant seasons. The rainfall partitioning components were significantly positively correlated with individual rainfall amounts. The minimum rainfall required to generate stemflow was 5.2 mm for R. pseudoacacia and 5.9 mm for P. tabuliformis during the growing season, and 3.1 mm for R. pseudoacacia and 6.0 mm for P. tabuliformis during the dormant season. Smaller rainfall events contributed to a lower percentage of rainfall amount, throughfall and stemflow but higher percentage of canopy interception loss. The percentage of throughfall and stemflow showed an increased tendency with increasing rain-fall characteristics, while the increasing rainfall characteristics resulted in a decrease in relative interception loss. During the growing season, leaf area index is significantly correlated with throughfall and interception loss of R. pseudoacacia, while there were no significant correlation between meteorological variables and rainfall partitioning. In general, the depth of rainfall partitioning can be predicted reasonably well by using the developed multiple regression models, but the proportions of rainfall partitioning had a relative lower accuracy using the developed models, especially for relative interception loss. To better predict canopy interception loss, other plant morphological and meteorological variables should be considered.
... Our study has implications for evaluating water consumption in areas with vegetation greening. Many national and international ecological programs have been launched for biodiversity conservation, climate change mitigation and desertification reversion (Malagnoux et al., 2007;Strassburg et al., 2020). Revegetation is expected to increase vegetation greenness and to consequently disturb the hydrological cycle by reshaping ET processes. ...
Global vegetation greenness has likely enhanced evapotranspiration (ET) that has been assumed to be the primary contributor to water consumption in some regions. However, the proportion of each ET component and their changes given vegetation greening are unclear. In this study, we investigated the response of ET components, especially vegetation transpiration (Et) and soil evaporation (Es), to vegetation and climate changes in a typical dryland region, i.e., the Loess Plateau in China, where vegetation is significantly greening. We used a sophisticated hydrological model (i.e., the Variable Infiltration Capacity, VIC) to partition ET, which considers the water-energy balance and vegetation dynamics associated with satellite products of fractional vegetation cover, leaf area index, surface albedo, and radiation forcing. The results showed that during the greening period of 2000–2018, Et had the largest increasing rate among the components and accounted for 31.8% of the ET. In contrast, Es showed a minor increase but occupied a larger proportion of about 60% of ET. Therefore, water consumption was primarily from Es rather than Et despite the increased proportion of Et. Vegetation greening certainly intensified Et, but also substantially constrained Es with a rate of −2.36 mm yr⁻¹. Increasing water availability (i.e., more precipitation) on the Loess Plateau made the largest contribution to the increase in the annual ET compared with vegetation greening and radiation forcing. These findings imply that the effect of vegetation greening on water consumption may be overestimated on the Loess Plateau. Our study highlights the importance of considering water balance and vegetation dynamics when evaluating ecological programs.
... Both of these factors have direct influences on plant growth and crop yields . Most of the undernourished human populations live in arid or semiarid regions that are one-third of the world's land area (Malagnoux et al. 2007), in addition to that 80% of food production comes from rainfed agriculture that grows about 60% of the world's cereal grains (Molden et al. 2011) providing livelihood for rural areas and producing food for the urban population. Drought stress is mainly caused by lack of rainfall or irrigation for a time period enough to exhaust soil moisture, and affect plant water supply that is high enough to cause injury to the plant (Blum 2005). ...
This chapter addresses the adverse effect of heat stress on plant growth, genes associated with heat stress tolerance and adaptive strategies that can be used to create heat-tolerant plants. CRISPR/Cas9 seems a promising approach regarding stress tolerance. The modified versions of CRISPR/Cas9 like CRISPRi, CRISPRa, base editing and CRISPR multiplexing offers more and more specificity and advanced editing options and minimizes the off-target effect. The versatility of CRISPR/Cas9 brings a new revolution in the field of plant science to alleviate abiotic stress like heat stress.KeywordsHeat stressCRISPR/Cas 9CRISPRiCRISPRaBase editingCRISPR multiplexing
... Both of these factors have direct influences on plant growth and crop yields (Bita and Gerats 2013). Most of the undernourished human populations live in arid or semiarid regions that are one-third of the world's land area (Malagnoux et al. 2007), in addition to that 80% of food production comes from rainfed agriculture that grows about 60% of the world's cereal grains (Molden et al. 2011) providing livelihood for rural areas and producing food for the urban population. Drought stress is mainly caused by lack of rainfall or irrigation for a time period enough to exhaust soil moisture, and affect plant water supply that is high enough to cause injury to the plant (Blum 2005). ...
High temperature is one of the major abiotic stresses causing huge yield losses in all crop plants. The challenges posed by global warming are the major antagonistic factors to realize seed yield potential of a genotype. There is a need to generate allelic variation in the existing gene pool for high-temperature tolerance. Induced mutagenesis holds great potential to cause lesions ranged from single base pair to large deletions resulting into development of spectrum of new gene combinations for high temperature tolerance. Advances in scientific methods, especially related to quantifying existing thermotolerance at seedling and reproductive stages, understanding the function of each genetic loci and their position on a chromosome, and deciphering biochemical pathways to analyze the effect of these genetic loci made it possible to measure genetic value of the mutant genes. Substantial efforts have been directed to generate variability in cereal crops such as wheat, rice, maize, and barley in the coded fraction of genome for heat stress tolerance which was exploited to decipher functional characterization of genetic loci at morphological, physiological, biochemical, and molecular levels as well as direct improvement of crop cultivars for warm locations. In wheat; mutations for stay green, thousand kernel weight, small heat shock protein, and stable meiosis; in rice; spikelet fertility, characters at seedling and reproductive stage, chlorophyllide a oxygenase; in maize; EF-Tu factor; in tomato; MAPK gene and mutations for brassinosteroids in barley have been found useful to develop heat-tolerant crop plants. A total of 14 heat-tolerant varieties have been developed through mutation breeding. Besides, precise mutagenesis techniques such as TILLING and CRISPR-cas9 have been found to be useful in developing heat-tolerant crop plants.KeywordsHigh-temperature toleranceMutantMutation breedingStay green mutantsHSPEF-Tu factorMAPKBrassinosteroidsWheatRiceMaizeBarleyTomatoTILLINGCRISPR
... A pesar del valor social de los bienes y servicios ecosistémicos comerciales y no comerciales que generan, la deforestación y la degradación del ecosistema natural amenazan los servicios que este brinda. El reemplazo de bosques nativos por cultivos de cosecha en regiones subhúmedas y semiáridas reduce la provisión de bienes y de servicios ecosistémicos aumentando la vulnerabilidad ecológica, productiva y económica del territorio (Geist y Lambin, 2004;Malagnoux et al., 2008). ...
En este trabajo se sistematizan las causas y respuestas que dan cuenta del área del bosque de caldén en Córdoba en el último siglo. A partir del marco conceptual Fuerza Presión Estado Impacto Respuesta, y usando datos de censos nacionales agropecuarios fue posible establecer las relaciones causales que explican dicho fenómeno. Las fuerzas motoras que ejercieron presión sobre el bosque de caldén han sido diferentes, así como sus impactos asociados con las catástrofes ecosistémicas sucedidas. Consecuentemente, las repuestas inducidas por dichas catástrofes han sido incluidas en la agenda colectiva, aunque de manera parcial, ya que los productores con bosque tuvieron una visión desintegrada con el resto de usos del suelo y no han considerado el aprovechamiento del bosque a perpetuidad. Comprender las causas y respuestas sociales de los procesos ocurridos en la superficie forestal constituye una herramienta útil para el diseño de renovadas políticas de conservación del bosque nativo.
... low water availability (Mazuela and Pilar 2013), high temperatures, and a frequent incidence of droughts. These zones represent a third of the continental area (Malagnoux et al., 2008). In the last 50 years, an increase in aridity has been reported in many areas of the planet (Dai, 2011). ...
The water crisis is a concern for Chilean agriculture. Testing new methods based on computer simulations is urgent to optimize irrigation. This study aimed to assess the model efficiency of HYDRUS 2D/3D simulations of volumetric water content (θ) and pore electrical conductivity (ECp) in an olive tree variety Kalamata under desert conditions. The model efficiency was assessed by comparing model simulations against observations of θ and ECp in five frequency domain reflectometry (FDR) sensors installed in the soil profile. Model simulations were improved by calibration using PEST software. Global sensitivity analysis was performed before calibration, analyzing both θ and ECp model outputs. Outcomes of sensitivity analysis indicate that the surface area associated with transpiration (ST) and the slope of the stress response function (s) are relevant parameters for θ and ECp. Both parameters were calibrated along with the saturated water content (θs) and pore size distribution (n) parameters of the second material. Calibration improved HYDRUS 2D/3D simulations for θ but not substantially for ECp. However, the Nash–Sutcliffe and the root mean square error (RMSE) are comparable with previous research for both variables. Furthermore, the s parameter decreases after calibration, indicating that Kalamata variety is tolerant to salt, which is in line with previous research. HYDRUS 2D/3D represents the θ variation in time and space with acceptable precision for olive trees under desert conditions. Additionally, subsequent studies should focus on the value of s, which is variety dependent, and ST, which requires the actual root volume.
... Forests are thought to contribute to creating suitable conditions for human livelihoods in drylands (Malagnoux et al., 2007). ...
Drylands cover more than 40% of Earth’s land surface and occur at the margin of forest distributions due to the limited availability of water for tree growth. Recent elevated temperature and low precipitation have driven greater forest declines and pulses of tree mortality on dryland sites compared to humid sites, particularly in temperate Eurasia and North America. Afforestation of dryland areas has been widely implemented and is expected to increase in many drylands globally to enhance carbon sequestration and benefits to the human environment, but the interplay of sometimes conflicting afforestation outcomes has not been formally evaluated yet. Most previous studies point to conflicts between additional forest area and water consumption, in particular water yield and soil conservation/desalinization in drylands, but were generally confined to local and regional scales. Our global synthesis demonstrates that additional tree cover can amplify water consumption through a nonlinear increase in evapotranspiration – depending on tree species, age, and structure – which will be further intensified by future climate change. In this review we identify substantial knowledge gaps in addressing the dryland afforestation dilemma, where there are trade-offs with planted forests between increased availability of some resources and benefits to human habitats versus the depletion of other resources that are required for sustainable development of drylands. Here we propose a method of addressing comprehensive vegetation carrying capacity, based on regulating the distribution and structure of forest plantations to better deal with these tradeoffs in forest multifunctionality. We also recommend new priority research topics for dryland afforestation, including: responses and feedbacks of dryland forests to climate change; shifts in the ratio of ecosystem ET to tree cover; assessing the role of scale of afforestation in influencing the tradeoffs of dryland afforestation; and comprehensive modelling of the multifunctionality of dryland forests, including both ecophysiological and socioeconomic aspects, under a changing climate.
... Arid and semi-arid lands cover about one-third of the terrestrial ecosystems and are inhabited by around one billion people, 1/4 of whom live in drylands and a large proportion of these are among the poorest in the world (Malagnoux et al., 2008). Land degradation is a major challenge in these ecosystems (Zerga, 2015). ...
free access link until December 12, 2021 : https://authors.elsevier.com/c/1dysf1L~GwQxbd
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Restoration of degraded lands is among the major challenges in Arid and semi-arid ecosystems. Therefore, in many regions where arid and semi-arid climates prevail, afforestation studies are carried out for restoration purposes. This study evaluated long-term afforestation practices in terms of ecosystem restoration in the arid lands of Central Anatolia, Turkey. For the study, sample afforestation sites of different ages were chosen in the Tuz Gölü-Konya basin. Species in the sites included black pine (Pinus nigra), Russian olive (Elaeagnus angustifolia), sweet almond (Prunus dulcis), black locust (Robinia pseudoacacia), narrow-leaved ash (Fraxinus angustifolia), and mahaleb cherry (Prunus mahalep). For each sampling area, the survival rates, height, and diameter values of species were recorded. Litter on the forest floor was sampled and then representative soil pits were dug at each site to sample soil from different layers (30, 60, 90, and 120-cm deep) of the profile. Bulk density, texture, lime content, pH, salinity, cation exchange capacity (CEC), and carbon (C) and nitrogen (N) concentration were determined for each soil sample. Approximately 2/3 of the black pine seedlings had died in the first 8–10 years of afforestation. The mortality rate in almond and mahaleb seedlings was approximately 20%. After 25–27 years of afforestation, 1/3 and 2/3 of the initial almond and Russian olive seedlings were lost, respectively. The mortality rate for other species was about 80% for the same period. Black pine had reached over 6.5 m, increasing its height by about 11-fold over the last 10–25 years. In the same period, the increase in the height of black locust was 2.8-fold, almond 2.6-fold, and ash 2.5-fold. The least height growth (1.7-fold) for this period was recorded for mahaleb. The amount of litter had increased 3- and 5-fold, at 15–17 years and 25–27 years of plantation age, respectively, compared to its increase in the open control site. After 15 years from planting, soil nitrogen (N) concentration at the first 30-cm depth had increased by about 1/3 compared to the open area. At the same depth, the soil pH value had decreased by 0.15 units after 25–27 years compared to the rest of the profile. These data implied that soil restoration had been initiated at all sites.
... Land management differences and crop choices associated with resource influxes may have particularly extensive ecological impacts on fragile and resource-limited dryland ecosystems (Malagnoux et al., 2007). Considering the global expansion of dryland agriculture, and complex socio-ecological and land management systems (Geist and Lambin, 2004), it is important to evaluate the regional impacts of agricultural regimes and their subsequent land-use practices on ecological communities. ...
Dryland agriculture has extensive impacts on surrounding ecosystems through its unintentional provision of food and water resources to local wildlife. We analyzed the response of a predator community of jackals, wolves and foxes to land-management choices, and how that response in turn affects native gazelles and Acacia vegetation in the Arava Valley of Israel. This hyperarid region is characterized by contrasting regimes comprising privatized (Moshavim) and communal (Kibbutzim) agricultural settlements, which provides ideal conditions for evaluating how land-management differences translate into crop choices, affecting resource availability and ecosystem changes. Integrating multi-year field observations of predators and gazelles with agricultural datasets, we show that shifts in land-use strategies have cascading ecological impacts. This is evident in the association of date orchards, an expanding land use especially in Kibbutzim, with shifts in the geographical and seasonal distributions of predators. Increased predator presence due to resource availability has displaced gazelles farther from settlements, subsequently impacting Acacia seed dispersal and recruitment. Considering the global expansion of dryland agriculture, the evidence of such socio-ecological cascading effects suggests the necessity to approach agricultural management at the landscape scale in desert regions.
... Although lowland riparian forests have a small footprint in arid landscapes, they represent critical moisture and thermal refugia for a range of species, many of which may be considered threatened or endangered (Albright et al., 2017;Seavy et al., 2009;Stromberg et al., 1996). However, dryland riparian forests are vulnerable to shifts in climate that affect root zone water availability to the key plant species because they cannot expand their range (Bertrand et al., 2011;Loarie et al., 2009;Malagnoux et al., 2007;Reidmiller et al., 2018), making them sensitive to climate change. ...
Vegetation distribution, composition and health in arid regions are largely dependent on water availability controlled by climate, local topography and geology. Despite a general understanding of climatic and geologic drivers in plant communities, trends in plant responses to water distribution and storage across areas under different local controls are poorly understood. Here we investigate the multi-decadal interactions between spatial heterogeneity of geologic controls and temporal variation of climate, and their impacts on water availability to vegetation and plant responses (via normalized difference vegetation index, NDVI) in a monsoon-driven arid region of southeastern Arizona. We find that grasslands display low NDVI and respond directly to monsoonal rainfall. In the uplands, vegetation on west-facing slopes and in canyons share similar NDVI averages and variability, suggesting that they both use water from surface-groundwater flow paths through fractured rocks. Along the San Pedro River, streamflow, groundwater, and NDVI in deciduous riparian woodlands are strongly responsive to monsoonal rainfall, but water availability stratifies between wet (perennial), intermediate, and dry reaches, underlain by different local geologic controls that affect water table elevation. These controls interact with the driving climate to affect water availability in the shallow alluvial aquifer of the riparian zone, a primary water source to the gallery phreatophytes. A recent shift toward a strengthened monsoon in the region has led to an increase in water availability for grasslands and for dry reaches of the San Pedro, while the benefit is more muted along wetter reaches, where the riparian forest shows signs of having reached its maturity, with diminished trends in NDVI. These results have implications for the future vulnerability of dryland vegetation to climate change, which may be either dampened or intensified by local controls such as geology.
... Forests in drylands are largely thought to generate a wealth of environmental services such as habitats that support biodiversity, protect against erosion, help water infiltrate soils and contribute to soil fertility (Malagnoux et al. 2008;Katerere et al. 2009;FAO 2015;Wilson et al. 2017) and increase the resilience of landscapes and communities to the impacts of climate change (FAO 2016). The FNC authority at Wad Al-Bashir forest is using more-adaptable species with high environmental and economic value. ...
Forests in the aridlands of Sudan are distinctive in nature and require special attention due to the great role they play as a first and last line of defense against southward desertification. Thus, to determine their conservative and protective needs based on current conditions in the Wad Al-Bashir Forest (WF), toward ensuring sustainable forest resources in these areas, we used a systematic field survey, existing and available documents review and key informant interviews (KII), to collect data from 08 December 2017 to 15 May 2018. A severe depletion and changes in the forest tree cover and composition were found during the field survey, where species such as Balanitis aegyptiaca is threatened and invasive species (e.g., Acacia nubica) have started to dominate. Reviewed documents have credited illegal cutting and agricultural activities for the changes in the forest status, whereas the KII indicated that past and current forest conservative and protective practices (CPPs), where forest clearance for agricultural, grazing, pests and disease control, were not given a deserved consideration as they relate to tree cutting and reforestation practices. Likewise, negligence of the needs of those who depend on the forest and inadequate funds have constrained implementation of some CPPs. Accordingly, on the basis of the results of this study, we recommend that CPPs associated with agriculture, grazing, forest fire, pest and disease control should be a top priority concern of forest authorities. Better financial support, which could be enriched by involving governmental and non-governmental organizations, is also needed to boost CPPs in the WF. Invasive species also need to be cleared and replaced by trees such as A. senegal and B. aegyptiaca that are of economic and environmental value.
... The most typical example is that alleviating the urban thermal stress in arid cities through increasing vegetation requires great attention to the water resources (e.g. surface water, groundwater and air moisture) available for planting and irrigating (Malagnoux et al 2007). Besides, not all cities with temperature elevated by urbanization require mitigation measures (Martilli et al 2020a(Martilli et al , 2020b. ...
The artificial impervious surface (AIS) counts among the most important components of the urban surface, and understanding how temperature changes with the AIS fraction (AISF) is crucial for urban ecology and sustainability. Considering the high heterogeneity among existing local studies, this study systematically analyzed the relationship between land surface temperature (LST) and AISF in 682 global cities. The LST-AISF relation was quantified by the coefficient (δLST, ΔLST/ΔAISF) of a linear regression model, which measures the LST change by one-unit (1%) increase in AISF. The LST was acquired from the Moderate Resolution Imaging Spectroradiometer (MODIS) daily products during 2014-2016, while the AISF was calculated as the proportion of AIS in each MODIS pixel according to the high-resolution Global Artificial Imperious Area (GAIA) product in 2015. Major results can be summarized as follows: (1) LST shows an increasing trend along AISF gradients (positive δLST) in most cities, with annually average daytime and nighttime δLST of 0.0219 [0.0205, 0.0232] ºC/% (values in parenthesis define the 95% confidence interval, hereinafter) and 0.0168 [0.0166, 0.0169] ºC/%, respectively, for global cities. (2) Daytime δLST varies substantially among cities, with generally stronger values in tropical and temperate cities, but weaker or even negative values in arid cities; while at night, cities located in the cold climate zone tend to have larger δLST. (3) The LST-AISF relation is also season-dependent, characterized by a greater δLST in warm months, especially for cities located in temperate and cold climate zones. (4) Driver analyses indicate that changes in surface biophysical properties, including vegetation conditions and albedo, are main contributors to the spatiotemporal variation of daytime and nighttime δLST, respectively. These results help us to get a quantitative and systematic understanding of the climatic impacts of urbanization.
... Multipurpose trees and shrubs are valuable components of arid and semiarid ecosystems and contribute to maintaining suitable conditions for crop cultivation, livestock grazing, and human livelihoods ( Malagnoux et al. 2007 ). They are defined as "all woody perennials that are purposefully grown to provide more than one significant contribution to the production and/or service functions of a land-use system. ...
Multipurpose trees and shrubs are vital components of arid and semiarid ecosystems. They offer both regulatory and production services, yet there is inadequate information on their actual use and factors affecting utilization of these plant resources. A study was carried out in three agroecological zones (counties) of southeastern Kenya: Machakos (subhumid zone), Kajiado (semiarid zone), and Kitui (arid zone). The research objective was to assess the local uses of multipurpose trees and shrubs and determine how socioeconomic factors (gender, type of occupation, and education level) influenced their use. A field survey was conducted along a 324-km transect across the three agroecological zones. Data were collected from 196 respondents using focus group discussions, key informants, and individual household questionnaires. A total of 86 plant species belonging to 47 plant families were recorded. The Mann-Whitney U-test revealed that women significantly used a higher number of different plant species than men (P < 0.05). The level of education and type of occupation also significantly affected plant use (P < 0.05), with subsistence farmers having primary or no formal education, reporting the highest number of species. Fifteen plant-use categories comprising production and service provision were identified. Plant species use-value index (UVI) revealed 10 indigenous and wild woody species of high value in the study area. Acacia tortilis (Forssk.) Hayne had the highest UVI of 0.33, followed by Commiphora africana (A. Rich.) Engl. (0.17), Terminalia brownii Fres. (0.13), and Zanthoxylum chalybeum Engl. (0.12). There was a significant positive correlation between the reporting frequency for woody species and the overall UVI (P < 0.05). Economic development, climate change, and land use changes jeopardize distribution, utilization, and knowledge preservation of multipurpose woody species. There is a need for monitoring and adoption of gender-sensitive strategies for their sustainable utilization in order to safeguard these unique plant resources from degradation and overexploitation.
... Desertification, the symbol of environmental degradation and economic poverty, is an urgent environmental problem in the world and has attracted worldwide attention (Malagnoux et al., 2007;Ofori and Showstack, 2010;Yu et al., 2017). Apart from threatening the environment, desertification has also been an obstacle to the global economic development (Tuoheti et al., 2013). ...
Desertification is one of the most serious environmental problems in the world, especially in the arid desert regions. Combating desertification, therefore, is an urgent task on a regional or even global scale. The Taklimakan Desert in China is the second largest mobile desert in the world and has been called the “Dead Sea” due to few organisms can exist in such a harsh environment. The Taklimakan Desert Highway, the longest desert highway (a total length of 446 km) across the mobile desert in the world, was built in the 1990s within the Taklimakan Desert. It has an important strategic significance regarding oil and gas resources exploration and plays a vital role in the socio-economic development of southern Xinjiang, China. However, wind-blow sand seriously damages the smoothness of the desert highway and, in this case, mechanical sand control system (including sand barrier fences and straw checkerboards) was used early in the life of the desert highway to protect the road. Unfortunately, more than 70% of the sand barrier fences and straw checkerboards have lost their functions, and the desert highway has often been buried and frequently blocked since 1999. To solve this problem, a long artificial shelterbelt with the length of 437 km was built along the desert highway since 2000. However, some potential problems still exist for the sustainable development of the desert highway, such as water shortage, strong sandstorms, extreme environmental characteristics and large maintenance costs. The study aims to provide an overview of the damages caused by wind-blown sand and the effects of sand control measures along the Taklimakan Desert Highway. Ultimately, we provide some suggestions for the biological sand control system to ensure the sustainable development of the Taklimakan Desert Highway, such as screening drought-resistant species to reduce the irrigation requirement and ensure the sound development of groundwater, screening halophytes to restore vegetation in the case of soil salinization, and planting cash crops, such as Cistanche, Wolfberry, Apocynum and other cash crops to decrease the high cost of maintenance on highways and shelterbelts.
... These areas are among the most fragile ecosystems in the world due to recurrent droughts and the growing overexploitation of scarce resources. Arid and semi-arid areas occupy about one-third of the earth's land surface and account for roughly one billion human inhabitants, who are often among the poorest in the world (Malagnoux et al. 2007). Forests, trees, and herbaceous plants are essential components of arid-zone ecosystems. ...
Forest tree species produce litter, which is the plant/soil interface that ensures the maintenance of soil fertility whose properties depend on the botanical species considered. The differences of properties are marked in the nature of the decomposition processes and the forms of humus which result from it. In this study, the physicochemical characteristics and biological activity of litter were compared in coniferous plots located in the semi-arid and the arid zones of western Algeria. The objective of this work was to characterize and compare the physical-chemical properties and microbiological characteristics of softwood forest litter in the semi-arid and arid areas of western Algeria. We analyzed the properties of 50 samples of Aleppo pine litter collected from five stations in each zone. Analysis results show a highly significant difference (p<0.05) in the physical-chemical properties between the semi-arid and arid zone: humidity (20.7% – 6.51%), pH (5.98 – 6.14), conductivity (0.42 mS/cm – 0.65 mS/cm), carbon (45.74% – 73.42%), nitrogen (1.17% - 0.86%) and C/N ratio (37.47 – 73.42). A comparison of the mean of microbial biomass and their efficacy reveals what is homogeneous in both zones, with a small difference in basal respiration.
The heterogeneity of these results indicates that such observations still need to be made in other forests of the Algerian territory in order to better understand the functioning of forest ecosystems and the effect of climate on these compartments, especially soil.
... Over the past few decades, extensive afforestation and reforestation efforts have been made in the semiarid and arid regions around the world with the primary purpose of controlling desertification and soil erosion as a way of conserving the ecological environment (Malagnoux et al., 2007;Cao et al., 2011;FAO, 2015). For instance, in 2000For instance, in -2010 49 billion ha of land were reforested or afforested with trees in dryland regions of the world, accounting for an increase in forest cover of 0.8% (14.7% to 15.5%, Hansen et al., 2013;Sexton et al., 2013;Bastin et al., 2017). ...
... They also provide a shelter for the wildlife and flora and produce a wide range of ecosystem services such as water balancing, mitigation of the microclimate, limitation of erosion, carbon sequestration and soil fertility restoration (e.g. Malagnoux et al. 2008;Conti and Díaz, 2013;de Oliveira Silveira et al., 2019). ...
The relationships between woody species, soil biota activity and soil quality were largely ignored in semi-arid areas. This study evaluated the influence of life form and seasonal variation on the mesofauna activity and soil chemical and microbial properties under three tree species (Quercus brantii (QU), Acer monspessulanum (AC) and Pistacia atlantica (PI), and three shrub species (Crataegus puntica (CR), Amygdalus scoparia (AM) and Lonicera nummularifolia (LO)) in a semiarid oak forest in western Iran. Soils were sampled beneath each individual woody species in spring and winter. Soil chemical and biological properties and soil mesofauna diversity were measured and soil quality index (SQI) was produced. The comparison of soil chemical properties under tree and shrub species showed that only soil total nitrogen (Ntot), available potassium (Kava) and soil organic carbon (SOC) were significantly higher under trees than shrubs (respective mean values for spring: 0.31 vs 0.19 %; 1304 vs 1103 mg/kg, 3.94 vs 3.16 %). In contrast, all of the studied soil biological characteristics including microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), basal respiration (BR), and substrate induced respiration (SIR) were significantly higher under trees than under shrubs (respective mean values for spring in mg/kg soil/day: 603.5 vs 431.2, 49.6 vs 35, 46 vs 35 and 57.6 vs 36.5). Besides, we found clear seasonal and species effects for most soil properties. Values were higher in spring than in winter and were the most similar for QU and AC for tree species (especially due to the higher content of SOC and MBN under these species in spring) and for AM and LO for shrub species. The Shannon-Wiener diversity index and richness of the soil mesofauna were significantly higher under trees than under shrubs (respective mean values for spring: 1.59 vs 1.09 and 6.5 vs 3.8). The Shannon-Wiener diversity and richness indices for soil mesofauna were positively linearly related to the soil quality index (SQI) in spring and winter. These relationships were weaker in winter than in spring and showed an increase of both indices from shrubs (LO, AM and CR) with low SQI values to trees (QU and AC) with higher SQI values. Based on these results, we conclude that these indices can be used as efficient soil bioindicators which can be helpful in restoration or conservation projects in semi-arid areas.
Keywords: Arthropods, Richness, Season, Tree, Shrub, Soil
... Arid lands are among the world most fragile ecosystem (Malagnoux et al. 2007). In North Africa they occupy more than 60 000 km 2 , about 34 % in Algeria (Le Houérou 1995). ...
... Afforestation has become the primary tool for ecological restoration in the northern Negev as in other degraded arid and semi-arid regions having common sandy and loamy soils (Zhu and Wang, 1993;Malagnoux et al., 2007). The planted trees function as artificial ecosystem engineer by providing litter, moisture, and shading, which accelerate (or facilitate) ecosystem functioning and as result affects the area rehabilitation state (Evans et al., 2016;. ...
The current state of many semi-arid to arid cultivated lands, based on their fertility and productivity rates, can be termed ‘degraded’ due to long-term overgrazing or unsustainable farming practices. Continuation of these cultivation methods at similar intensities will lead to un-changed or small further decrease of the land rehabilitation state, a term describing the potential for sustainable further agricultural use. Implementation of conservation management will induce a steady recovery process leading to increased vegetation cover and enhanced soil fertility. The increased vegetation, in turn, enhances litter production, soil fertility, ecosystem engineer activity and landform stabilization, factors that collectively permit achieving appropriate productivity for sustainable agricultural utilization. In contrast, massive soil disturbance, such as improper landform re-modelling or deep tillage, will damage the function of ecosystem engineers, leading to instability, a state where spontaneous recovery becomes impossible. Taking this data and translating it to practical guidelines for the farmer arise four problems: what is the starting point in long-term degraded area, what is the optional (maximal possible) state and what is the most suitable practice to use for reaching the optimal state, relating parameters as climate and erosion. Moreover, how can one represents rehabilitation or degradation processes relying on soil properties with different temporal changes? Therefore, the hypothesis is that only comparison of the soil properties in controlled cultivation to the common long-term used one, will enable to define the rehabilitation rate of the cultivation. In order to determine the rehabilitation state of different cultivations and the specific mechanisms affecting its value, a comprehensive study was carried out on different cultivated arid loess areas in Project Wadi Attir, the northern Negev, Israel. Soil fertility, productivity, landform stability and biological activity of conserved and heavily grazed rangelands, loess deposits, rocky slopes and agriculture terraces were analyzed before project implementation and during the following five years. Arid environments are characterized not only by low precipitation, but also by high yearly and inter-seasonal heterogeneity. Therefore, in order to calculate the net rehabilitation trend from changes in soil fertility, their values were normalized. A scheme based on two sets of reference plots was used. One control plot resembles the common cultivation in the studied plots, heavily grazed and intensely tilled. Separate plots were defined for the treatments of loess deposit and rocky slope. The second type of reference plots resembles the maximal fertility state achieved in the studied cultivations. The plot chosen in the Project Wadi Attir area was conserved from grazing and located on an abandoned ruminants enclosure overlaid with an ageing manure layer. The ratios between the soil fertility parameters of the studied treatments and their values in the reference plots reflect their net change.
The net sustainable changes of the outside plots with respect to soil fertility, soil organic matter, soil moisture and nutrient content were minimal and achieved at most 5%, whereas vegetal cover increased up to 30%. These rates are comparable to other studies in the northern Negev and other arid areas worldwide, reflecting the effect of the continuation of common cultivation in degraded areas.
The second group of treatments represents the conserved plots inside the farm. Changes in their yearly soil fertility reached 10% and the herbaceous biomass weight up to 100% per year, even in the tilled treatments. Increased infilterability, enhanced harvester ants activity and landform stability were also observed. These treatments represent a continuous rehabilitation mechanism. Further degradation was observed in un-planted and re-modelled limans outside the farm and expressed by a 15% annual decrease of the herbaceous biomass, compared to the common degraded loess cultivation.
The specific mechanisms of rehabilitation inside the farm were analyzed by separating the influence of conservation and tillage, as found in the study site. Conservation increased the herbaceous biomass weight by 100% per year in the loess deposits and by 47% in the rocky slope, leading to annual fertility changes as high as 10%. This mechanism is correlated to the lack of flora harvesting and trampling by the grazed animals, resulting in restoration of biogenic crust and litter supply. The proposed mechanism is based on a combination of the conservation influence of reduced tillage and litter management.
Three additional rehabilitation mechanisms were defined as affected by the existence of ecosystem engineers, the sloped outlines of the plots, the 3-dimentional liman shape and the implemented soil practices.
The rehabilitation mechanism of the ecosystem engineers was found to be characterized by an initially patchy landform surrounding the ecosystem engineers. This patchy concentric form expanded to a state of whole area recovery, indicating a possible transformation from shrublands into grasslands by proper management. The rehabilitation efficiency of shrubs and harvester ants is high, thereby rehabilitating these cultivated lands under proper practices, higher than the rehabilitation of the local shrub species.
The rehabilitation mechanism of the sloping area combines the influence of conservation, existence of ecosystem engineers and the sloped outlines of plots. Altogether these influences enhanced the downslope accumulation of fertile sediments, thereby enhancing areal recovery.
The rehabilitation mechanism of the limans was found to be influenced by their unique landform design in addition to that of the conservation, sloped shape of their sides and the influence of ecosystem engineers on the planted savanna trees. These influences were expressed by low herbaceous biomass inside the limans followed by enhanced growth. In further stages the liman recovery mechanism expanded and influenced the surroundings. This study indicates that pasture utilization increased from less than 1 ruminant/ha year under conserved cultivation to fourfold. Five years of conservation increased the Nitrogen sequestration by 35%, Phosphate by 15%, Potassium by 20% and soil organic content by 30%. The principles used in this study can be used in other cultivated arid areas leading to sustainable dryland management.
... However, the biophysical condition of the area works as a strong modifier in the water provisioning services of forests (Calder, 2002(Calder, , 2007Negi and Joshi, 2004). However, while there is agreement on 'the role of the upstream forest cover in ensuring the delivery of high-quality water', there is far less consensus on observations like 'the upstream forest cover having a positive effect on the downstream annual and seasonal flows' as they have been found to be context-dependant, especially in arid or semi-arid ecosystems (Malagnoux et al., 2007;Van Dijk and Keenan, 2007;Tobella et al., 2014;Ilstedt et al., 2016). In Carvalho-Santos et al. (2014) can be found a summary of the extensive literature on the forest-water nexus. ...
Inhabitants of the upper Himalayan regions entertain a belief that the Chir Pine trees are ingressing the Broadleaf forest areas and that these areas are gradually turning into water stressed regions as Chir Pines adversely influence water recharge and water availability. This paper examines whether and to what extent the Chir Pine forest areas are water stressed compared to Broadleaf forest areas by studying the household coping cost in relation to water stress. We use the coping cost differences thereafter to value the relative water provisioning services of forest types. We conduct multiple focus group discussions, a questionnaire survey and statistical analyses to derive the results. Results show all households, except the ones living near Deodar forest, to face water stress in summer but the Chir Pine areas are the most water-stressed. Both comparison of mean and multivariate regressions of water collection time and other coping costs show that the villagers surrounded by Deodar, Deodar mix pine, Broadleaf mix bush or Broadleaf mix pine forests spend much less time for water collection and spend less on water treatment and storage compared to the villagers surrounded by Chir Pine forest irrespective of elevation, aspect or model used. These differences in water collection time amount to a wage income loss between USD 31 and USD 318 in India, and between USD 23 and USD 238 in Nepal per year per household, in Chir Pine areas compared to other forest areas.
... Among the different abiotic factors, soil water availability is considered as a significant variable controlling the soil C storage in arid and semi-arid ecosystems (Meza et al. 2018). Management strategies focusing on the C sequestration by restoring the existing vegetation would be effective in mitigating climate change and its effects on these ecosystems (Malagnoux et al. 2007). To date, only a few studies on biomass and C pools have been carried out in these ecosystems (Bonino 2006;Wagner et al. 2015). ...
Assessment of carbon pools in semi-arid forests of India is crucial in order to develop a better action plan for management of such ecosystems under global climate change and rapid urbanization. This study, therefore, aims to assess the above- and belowground carbon storage potential of a semi-arid forest ecosystem of Delhi. For the study, two forest sites were selected, i.e., north ridge (NRF) and central ridge (CRF). Aboveground tree biomass was estimated by using growing stock volume equations developed by Forest Survey of India and specific wood density. Understory biomass was determined by harvest sampling method. Belowground (root) biomass was determined by using a developed equation. For soil organic carbon (SOC), soil samples were collected at 0–10-cm and 10–20-cm depth and carbon content was estimated. The present study estimated 90.51 Mg ha−1 biomass and 63.49 Mg C ha−1 carbon in the semi-arid forest of Delhi, India. The lower diameter classes showed highest tree density, i.e., 240 and 328 individuals ha−1 (11–20 cm), basal area, i.e., 8.7 (31–40 cm) and 6.08 m2 ha−1 (11–20 cm), and biomass, i.e., 24.25 and 23.57 Mg ha−1 (11–20 cm) in NRF and CRF, respectively. Furthermore, a significant contribution of biomass (7.8 Mg ha−1) in DBH class 81–90 cm in NRF suggested the importance of mature trees in biomass and carbon storage. The forests were predominantly occupied by Prosopis juliflora (Sw.) DC which also showed the highest contribution to the (approximately 40%) tree biomass. Carbon allocation was maximum in aboveground (40–49%), followed by soil (29.93–37.7%), belowground or root (20–22%), and litter (0.27–0.59%). Our study suggested plant biomass and soils are the potential pools of carbon storage in these forests. Furthermore, carbon storage in tree biomass was found to be mainly influenced by tree density, basal area, and species diversity. Trees belonging to lower DBH classes are the major carbon sinks in these forests. In the study, native trees contributed to the significant amount of carbon stored in their biomass and soils. The estimated data is important in framing forest management plans and strategies aimed at enhancing carbon sequestration potential of semi-arid forest ecosystems of India.
Brachystegia boehmii and Piliostigma thonningii seeds were assessed in a study conducted at the Botswana University of Agriculture and Natural Resources. Ten treatments were included in a completely randomised design (CRB) experiments, which included nicking soaking in sulphuric acid for 15, 30, 45 and 60 minutes, submerging seed in boiling water for one, three and five minutes and hot water (allowed to cool for twenty-four hours). Seeds were allowed to germinate for 30 days in the laboratory. The obtained germination data were subjected to analysis of variance (ANOVA). B. boehmii seeds that were exposed to hot water (allowed to cool for 24 hours), sulphuric acid and nicking did not show a significant difference from their untreated counterparts. Lowest germination rate of B. boehmii was discovered in boiled seeds. In comparison to untreated seeds, Piliostigma thonningii seeds nicked and those treated with sulphuric acid showed significantly higher germination rates. The germination of P. thonningii seeds was not enhanced by boiling and hot water. The outcome of this study showed that B. boehmii has a permeable seed coat and the outcome is opposite for P. thonningii.
A field experiment was carried out to assess the effects of different sources of seed and organic fertilizer with the aim of investigating early growth response to The experiment was conducted at the Department of F of Agriculture, Nasarawa State University Keffi, Shabu Factorial Experiment in a Completely Randomized Block Design (CRBD), analyzed with respect to three sources of seed and 4 types of leaf count, collar girth, leave length, leave area and leave width. The results of parameter assessed on the basis of locations shows that seedlings from Lafia had the highest mean height of 8.67±2.15cm at 14, while seedling from Nasarawa Toto had the least mean height of 8.19±2.28cm. The result of leave count revealed that seedling from Nasarawa Toto had the highest leave count of 5.26±1.36 while leave count of seedlings from Lafia had the least le count of 5.08±1.50. The result of growth variables revealed that, treated with mixture of cow dung and poultry droppings were 9.23±2.28cm for height, 1.88±0.36cm for collar girth, 5.08±3.60 for number of leaf, 4.79±1.38 for mean value of seedlings treated with poultry dung were 7.87±2.23cm for height, 2.04 ± 0.34cm for collar girth, 5.47±1.48 for number of leaves, 4.70±1.58 for leave length while mean value of seedlings treated with cow dung were 8.56±2.14 5.04±1.41 for number of leaves, and 4.49±1.36 for leave length. The result of the ANOVA revealed that, the effects of location and all the treatments were highly significant on plant height, collar girth, number of leaves, leave length, leave width and leave area re P<0.05, result of correlation analysis revealed that there was a significant correlation between the variables assessed.While the on plant height had coefficient of R about 48% effects on plant height of and organic manure. The study reveals that seeds growth performance.It also showed that organic manure support growth senegalensis seedlings more appropriately.
Forest degradation is a severe problem that threatens forest resources around the world. The south Mediterranean forests are dryland types of forests prospering in arid and semi-arid climates, making them more vulnerable to degradation. This work aims to present a methodology that combines three approaches: geographical information systems (GIS), machine learning, and cellular automata, to assess the spatiotemporal behavior of south Mediterranean dryland-type forests (case study, the Ain Leuh Forest, Middle Atlas, Morocco). First, we used satellite images to establish forest state maps defining five classes: dense cedar cover (C1), low cedar cover (C2), dense Quercus cover (Q1), low Quercus cover (Q2), and bare soil (BS). Then, based on those historical maps, two scenarios were defined, P1: 1990–2000 and P2: 2000–2010, and the relative class transitions. Second, a logistic regression algorithm was used to create the probability transition maps. The model considered four factors (altitude, slope, aspect, and distance from the forest edge). Third, a cellular automata model was implemented to predict the forest's future state. The model takes into input the initial state of the forest, and the probability of transition drives it. Our model was first calibrated by predicting the 2019 forest state, evaluated by Kappa de Cohen and cosine distance coefficients, then projected to predict the 2030 forest state. Results showed the efficiency of combining logistic regression and cellular automata models to predict the form (density of area) and the rate of south Mediterranean dryland forest degradation.
A field experiment was carried out to assess the effects of different sources of seed and organic fertilizer with the aim of investigating early growth response to The experiment was conducted at the Department of F of Agriculture, Nasarawa State University Keffi, Shabu Factorial Experiment in a Completely Randomized Block Design (CRBD), analyzed with respect to three sources of seed and 4 types of leaf count, collar girth, leave length, leave area and leave width. The results of parameter assessed on the basis of locations shows that seedlings from Lafia had the highest mean height of 8.67±2.15cm at 14, while seedling from Nasarawa Toto had the least mean height of 8.19±2.28cm. The result of leave count revealed that seedling from Nasarawa Toto had the highest leave count of 5.26±1.36 while leave count of seedlings from Lafia had the least le count of 5.08±1.50. The result of growth variables revealed that, treated with mixture of cow dung and poultry droppings were 9.23±2.28cm for height, 1.88±0.36cm for collar girth, 5.08±3.60 for number of leaf, 4.79±1.38 for mean value of seedlings treated with poultry dung were 7.87±2.23cm for height, 2.04 ± 0.34cm for collar girth, 5.47±1.48 for number of leaves, 4.70±1.58 for leave length while mean value of seedlings treated with cow dung were 8.56±2.14 5.04±1.41 for number of leaves, and 4.49±1.36 for leave length. The result of the ANOVA revealed that, the effects of location and all the treatments were highly significant on plant height, collar girth, number of leaves, leave length, leave width and leave area re P<0.05, result of correlation analysis revealed that there was a significant correlation between the variables assessed.While the on plant height had coefficient of R about 48% effects on plant height of and organic manure. The study reveals that seeds growth performance.It also showed that organic manure support growth senegalensis seedlings more appropriately.
Among abiotic stresses, heat and drought stresses present a considerable threat to the global food production. Cereals and grain legumes provide major dietary demands worldwide but in changing climate scenario enhancing food production for feeding evergrowing population is very challenging. Therefore, breeding cultivars with drought and heat stress tolerance traits are going to be a challenging task in the coming decades. Plants respond to heat or drought stress by triggering a cascade of molecular events and counter the stress by switching on various stress-responsive genes. However, drought and heat tolerance traits are very complex and poorly understood mechanisms and substantial G × E and epistatic effects offer major bottlenecks to the genetic gains against both stresses. Therefore, in current situation attention should be given to the rapid and precise introgression of heat and drought tolerance-related gene(s)/QTLs to the susceptible cultivars through integration of molecular breeding tools. Innovative techniques like genomic selection (GS) and genome wide association study (GWAS) are gaining importance as they capture the quantitative variation underlying abiotic stress tolerance and provide a great impetus to the progress of breeding for heat and drought tolerance.KeywordsToleranceMolecular markersQTLGenomicsGenomic selection
After addressing the subject of conservation of Moroccan and African rangelands, in this work we try to linkage these lands on a global scale. With the pandemic of COVID-19 and the impacts of climate change these rural populations have suffered great problems. Their weak or absent means of resistance pose a real handicap to live in peace. The only way is to migrate to places where they can continue with their cattle this battle of life or death. On the other hand and from the point of view of natural resources, these lands have immense power to manage a whole community by the richness of these medicinal plants and their soils. Due to the lack of interest in these areas, there is a risk of losing an entire ecosystem rich in fauna, flora, habitat, nomadic population and traditions. In this work we propose many recommendations: natural, socioeconomic , cultural and public health.
The imprint of geologic, climatic and anthropogenic memory as controls on geomorphic river diversity is assessed for twelve River Styles in the Sabarmati Catchment. Geologic controls are the primary determinant of river character and behavior in the hinterland and pediment landscape units, where headwater streams transition to partly confined valleys and gorges with distinct structural lineations in a rectangular drainage network. Climate memory imprints entrenched rivers that make up alluvial fan and alluvial plain landscape units of the mid-lower catchment, shaped by phases of sediment aggradation and subsequent incision in response to enhanced monsoonal rains around 10 ka. Terraces constrain channels within confined and partly confined valleys with occasional and discontinuous floodplains respectively. Laterally unconfined channels are only found in the lower parts of the catchment, immediately upstream of the estuary/delta. Limited space for adjustment, impacts of flow regulation and ephemeral conditions restrict the range of contemporary river morphodynamics, but ridges and swales and abandoned channels on floodplains indicate more dynamic conditions in the past. Impacts of anthropogenic memory are most pronounced in the stopbank-controlled, barrage- and dam-impacted reaches, especially in the cities of Gandhinagar and Ahmedabad. An explanation of controls upon geomorphic river diversity, including an assessment of the role of stream power, presents a coherent platform to develop geomorphologically-informed approaches to river management.
The quantification of carbon storage in vegetation biomass is a crucial factor in the estimation and mitigation of CO2 emissions. Globally, arid and semi-arid regions are considered an important carbon sink. However, they have received limited attention and, therefore, it should be a priority to develop tools to quantify biomass at the local and regional scales. Individual plant variables, such as stem diameter and crown area, were reported to be good predictors of individual plant weight. Stand-level variables, such as plant cover and mean height, are also easy-to-measure estimators of above-ground biomass (AGB) in dry regions. In this study, we estimated the AGB in semi-arid woody vegetation in Northeast Patagonia, Argentina. We evaluated whether the AGB at the stand level can be estimated based on plant cover and to what extent the estimation accuracy can be improved by the inclusion of other field-measured structure variables. We also evaluated whether remote sensing technologies can be used to reliably estimate and map the regional mean biomass. For this purpose, we analyzed the relationships between field-measured woody vegetation structure variables and AGB as well as LANDSAT TM-derived variables. We obtained a modelbased ratio estimate of regional mean AGB and its standard error. Total plant cover allowed us to obtain a reliable estimation of local AGB, and no better fit was attained by the inclusion of other structure variables. The stand-level plant cover ranged between 18.7% and 95.2% and AGB between about 2.0 and 70.8 Mg/hm2. AGB based on total plant cover was well estimated from LANDSAT TM bands 2 and 3, which facilitated a model-based ratio estimate of the regional mean AGB (approximately 12.0 Mg/hm2) and its sampling error (about 30.0%). The mean AGB of woody vegetation can greatly contribute to carbon storage in semi-arid lands. Thus, plant cover estimation by remote sensing images could be used to obtain regional estimates and map biomass, as well as to assess and monitor the impact of land-use change on the carbon balance, for arid and semi-arid regions.
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Tetraclinis articulata is a xerothermic Mediterranean conifer native from NW Africa that grows under semiarid conditions in the Atlas Mountains. This species is particularly well adapted to water scarcity and forms xeric woodlands subjected to recurring drought, aridification and overexploitation. Wood of T. articulata has been considered of limited dendrochronological value due to abundant anatomical anomalies in their growth rings. We studied tree-ring growth and tree-ring features to check its dendrochronological potential and evaluate their climatic signals and drought legacy effects at two semiarid sites with contrasting elevation in Morocco. Tree-ring boundaries were properly identified on wood cores from 60 to 68% of the sampled trees. Intra-annual wood density fluctuations (IADF), microrings, missing rings and rings with undefined limits were most abundant at the low-elevation coastal site than at the mountain site. Microring and missing ring abundance was inversely related to tree-ring growth, independent of cambial age, and mostly dependent on drought occurrence. IADF frequency was independent of tree-ring growth but inversely related to cambial age. A complex response of IADF formation to cool March to June conditions was found at the low-elevation coastal site, while IADF formation in the mountain site was related to May water availability. Undefined ring limits were observed only at the low-elevation site, showing positive relationships with elevated maximum temperatures in previous winter. Previous winter rainfall favored radial growth, but a significant legacy effect of water availability was evident up to three years prior to growth. Tree-ring growth was mostly related to water availability 33 and 26 months prior to growth at low-elevation and mountain sites, respectively. The obtained results reveal a very plastic cambial activity and a strong ability of T. articulata to withstand drought even for long periods.
This paper aims to evaluate the possibility of using the roofs of habitations in Caruaru city in the semiarid region of Pernambuco, Brazil, for two purposes: as green roofs to mitigate extreme temperatures inside the houses and for rainwater harvesting and storage for potable purposes. For this, a preliminary study was carried out with inside and outside temperature monitoring of rooms with a green roof and conventional roof to verify the thermal variation in a real situation. Furthermore, the potential of rainwater harvesting for Caruaru city was evaluated based on precipitation data provided by the Water National Agency and an estimation of the available roof area (buildings and houses). In this context, two scenarios were analysed: (scenario 1) the whole roof surface was used for rainwater harvesting and saving and (scenario 2) green roofs were implanted in part of the roofs.
The results of this preliminary study indicated that the use of green roofs resulted in lower temperature variations throughout the day, decreased internal temperatures, and decreased thermal amplitude in relation to a conventional roof (with tiles). Regarding the reduction of the catchment area because of the recommended use of green roofs in a semiarid region, considering green roof application just over the bedrooms (which was considered to cover 16 m² in total), the water saving potential of the public supply system decreased, with a monthly average of 23.13% versus 28.43% (without green roofs). Implanting green roofs in part of the roofs of houses, although there is a reduction in the rainwater volume that can be harvested, can result in an increase in thermal comfort, whereas this is not feasible with the use of the entire roof area to harvest potable water. Thereby, the results indicate that the simultaneous use of the two kinds of roofs (conventional and green) is feasible even in a semiarid climate.
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