scholarly journals A regional view of the linkages between hydro-climatic changes and deforestation in the Southern Amazon

Author(s):  
Sly Wongchuig ◽  
Jhan Carlo Espinoza ◽  
Thomas Condom ◽  
Hans Segura ◽  
Josyane Ronchail ◽  
...  

<p>Linking the Amazonian deforestation to changes in the hydrological cycle remains a puzzling question, addressed here through the use of recent global databases analyzing the relations between key hydro-climate variables (Precipitation (P), potential and actual evapotranspiration (PET and AET, respectively)), the surface water-energy balance and indices of forest cover change (regional forest loss ratio -RFL and regional non-forest vegetation ratio -RNF) for Southern Amazon (south of 8°S) and over the 1981-2018 period. The Southern Amazon constitutes a peculiar region due to specific climatic characteristics and shows a higher significant deforestation rate in comparison with the Northern Amazon. We further subdivided the study region into three subregions called Southern Bolivian Amazon (15° S‒21° S, 57° W‒70° W), Southern Peruvian Amazon (8° S‒15° S, 77° W‒65° W) and Southern Brazilian Amazon (8° S‒15° S, 65° W‒50° W). The surface water-energy balance is analyzed using a pixel-based Budyko-like theoretical framework approach, which discriminates energy-limited regions from water-limited regions. Southern Bolivian Amazon is shown to have undergone the strongest forest transition, becoming water-limited in conjunction with high forest loss. In this region, there is a significant relation between RFL values above 40%, P decrease, PET increases and AET decrease. These results suggest that areas with RNF values higher than 40% are prone to shift from an energy-limited to a water-limited state and remain trapped in this new state. Regions further north remain energy-limited due to minor P changes and even though significant increases in PET and decreases in AET are observed, associated with deforestation (high values RFL). This is typically the case in the ‘Arc of Deforestation’. In the Southern Bolivian Amazon, land use transition is associated with much larger changes from closed forest to a low-tree cover state as compared to regions further north - by at least a factor three as a proportion of area. Our findings indicate a clear link between hydro-climatic changes and deforestation, providing a new perspective on their spatial variability on a regional scale.</p><p> </p><p>This research is part of the French AMANECER-MOPGA project.</p>

2014 ◽  
Vol 11 (2) ◽  
pp. 2011-2044
Author(s):  
R. Barthel

Abstract. Today there is a great consensus that water resources research needs to become more holistic, integrating perspectives of a large variety of disciplines. Groundwater and surface water (hereafter: GW and SW) are typically identified as different compartments of the hydrological cycle and were traditionally often studied and managed separately. However, despite this separation, these respective fields of study are usually not considered to be different disciplines. They are often seen as different specialisations of hydrology with different focus, yet similar theory, concepts, methodology. The present article discusses how this notion may form a substantial obstacle in the further integration of GW and SW research and management. The article focusses on the regional scale (areas of approx. 103 to 106 km2), which is identified as the scale where integration is most greatly needed, but ironically the least amount of fully integrated research seems to be undertaken. The state of research on integrating GW and SW research is briefly reviewed and the most essential differences between GW hydrology (or hydrogeology, geohydrology) and SW hydrology are presented. Groundwater recharge and baseflow are used as examples to illustrate different perspectives on similar phenomena that can cause severe misunderstandings and errors in the conceptualisation of integration schemes. It is also discussed that integration of GW and SW research on the regional scale necessarily must move beyond the hydrological aspects, by collaborating with social sciences and increasing the interaction between science and the society in general. The typical elements of an ideal interdisciplinary workflow are presented and their relevance with respect to integration of GW and SW is discussed. The overall conclusions are that GW hydrology and SW hydrogeology study rather different objects of interest, using different types of observation, working on different problem settings. They have thus developed different theory, methodology and terminology. Yet, there seems to be a widespread lack of awareness of these differences which hinders the detection of the existing interdisciplinary aspects of GW and SW integration and consequently the development of truly unifying, interdisciplinary theory and methodology. Thus, despite having the ultimate goal of creating a more holistic approach, we should start integration by analysing potential disciplinary differences. Improved understanding among hydrologists of what interdisciplinary means and how it works is needed. Hydrologists, despite frequently being involved in multidisciplinary projects, are not sufficiently involved in developing interdisciplinary strategies and do usually not regard the process of integration as such as a research topic of its own. There seems to be a general reluctance to apply (truly) interdisciplinary methodology because this is tedious and few, immediate incentives are experienced.


2017 ◽  
Vol 115 (1) ◽  
pp. 121-126 ◽  
Author(s):  
Kimberly M. Carlson ◽  
Robert Heilmayr ◽  
Holly K. Gibbs ◽  
Praveen Noojipady ◽  
David N. Burns ◽  
...  

Many major corporations and countries have made commitments to purchase or produce only “sustainable” palm oil, a commodity responsible for substantial tropical forest loss. Sustainability certification is the tool most used to fulfill these procurement policies, and around 20% of global palm oil production was certified by the Roundtable on Sustainable Palm Oil (RSPO) in 2017. However, the effect of certification on deforestation in oil palm plantations remains unclear. Here, we use a comprehensive dataset of RSPO-certified and noncertified oil palm plantations (∼188,000 km2) in Indonesia, the leading producer of palm oil, as well as annual remotely sensed metrics of tree cover loss and fire occurrence, to evaluate the impact of certification on deforestation and fire from 2001 to 2015. While forest loss and fire continued after RSPO certification, certified palm oil was associated with reduced deforestation. Certification lowered deforestation by 33% from a counterfactual of 9.8 to 6.6% y−1. Nevertheless, most plantations contained little residual forest when they received certification. As a result, by 2015, certified areas held less than 1% of forests remaining within Indonesian oil palm plantations. Moreover, certification had no causal impact on forest loss in peatlands or active fire detection rates. Broader adoption of certification in forested regions, strict requirements to avoid all peat, and routine monitoring of clearly defined forest cover loss in certified and RSPO member-held plantations appear necessary if the RSPO is to yield conservation and climate benefits from reductions in tropical deforestation.


2021 ◽  
Vol 43 (3) ◽  
Author(s):  
Duong Nguyen Dinh ◽  
Cam Lai Vinh

Natural forests are a basic component of the earth's ecology. It is essential for biodiversity, hydrological cycle regulation, and environmental protection. Natural forests are gradually degraded and reduced due to timber logging, conversion to cropland, production forests, commodity trees, and infrastructure development. Decreasing natural forests results in loss of valuable habitats, land degradation, soil erosion, and imbalance of water cycle on the regional scale. Thus, operational monitoring of natural forest cover change has been in the interest of scientists for a long time. Current forest mapping methods using remotely sensed data provide limited capability to separate natural forests and planted forests. Natural forest statistics are often generated using official forestry national reports that have different bias levels due to different methodologies applied in different countries in forest inventory. Over the last couple of decades, natural forests have been over-exploited for various reasons. This led to forest cover degradation and water regulation capability, which results in extreme floods and drought of a watershed in general. This situation demands an urgent need to develop a fast, reliable, and automated method for mapping natural forests. In this study, by applying a new method for mapping natural forests by Landsat time series, the authors succeeded in mapping changes of natural forests of Cambodia, Laos, and Vietnam from 1989 to 2018. As a focused study area, three provinces: Ratanakiri of Cambodia, Attapeu of Laos, and Kon Tum of Vietnam were selected. The study reveals that after 30 years, 51.3% of natural forests in Ratanakiri, 27.8% of natural forests in Attapeu, and 50% of natural forests in Kon Tum were lost. Classification results were validated using high spatial resolution imagery of Google Earth. The overall accuracy of 99.3% for the year 2018 was achieved.


2021 ◽  
Author(s):  
Matt Cooper ◽  
Max Dickens ◽  
Sopan Patil ◽  
Huw Thomas

<p>Natural Flood Management (NFM) seeks to utilise natural processes within the landscape to reduce flood risk and is increasingly being viewed as a sustainable, cost effective, and complementary addition to flood defence infrastructure.  One NFM measure is to increase the proportion of forested lands within catchments draining to the communities at risk. Tree cover has good potential to reduce flood risk by increasing canopy evaporation, enhancing below and above ground flood storage and slowing the flow of water towards streams.  However, the extent to which these mechanisms are superior for forestry, compared to other land uses, and how they vary throughout the year and for different forest types remains difficult to predict, which is a major gap in our ability to quantify how forest cover can help reduce flood risk.</p><p> </p><p>Here, we present a study that utilises LoRaWAN, a developing wireless sensor network technology, to provide real time collection of canopy interception and streamflow data at the Pennal catchment in Wales, UK.  LoRaWAN is an emerging Low Power Wide Area Network (LPWAN) protocol designed for Internet of Things (IoT) applications. The capability of LoRaWAN to operate under harsh attenuation and interference conditions make it well suited to the forest catchment area which is characterised by dense vegetation and varied topography.</p><p> </p><p>This study will utilise a network of tipping bucket rain gauges and stream flow monitors distributed in different forest types and densities. The rain gauges and water level monitors are the end devices (IoT things) in the network which perform a direct communication with LoRaWAN Gateways, from which the data is ‘pushed’ to a server for storing and assimilation. The data will be used to develop and validate a coupled canopy and soil hydrology model.  This will guide forest management and aid in quantifying the effects of natural flood management techniques, initially within the Pennal catchment, with a view to expanding to the regional scale.</p>


2020 ◽  
Vol 12 (1) ◽  
pp. 187 ◽  
Author(s):  
Viktor Myroniuk ◽  
Mykola Kutia ◽  
Arbi J. Sarkissian ◽  
Andrii Bilous ◽  
Shuguang Liu

Satellite imagery of 25–30 m spatial resolution has been recognized as an effective tool for monitoring the spatial and temporal dynamics of forest cover at different scales. However, the precise mapping of forest cover over fragmented landscapes is complicated and requires special consideration. We have evaluated the performance of four global forest products of 25–30 m spatial resolution within three flatland subregions of Ukraine that have different forest cover patterns. We have explored the relationship between tree cover extracted from the global forest change (GFC) and relative stocking density of forest stands and justified the use of a 40% tree cover threshold for mapping forest in flatland Ukraine. In contrast, the canopy cover threshold for the analogous product Landsat tree cover continuous fields (LTCCF) is found to be 25%. Analysis of the global forest products, including discrete forest masks Global PALSAR-2/PALSAR Forest/Non-Forest Map (JAXA FNF) and GlobeLand30, has revealed a major misclassification of forested areas under severe fragmentation patterns of landscapes. The study also examined the effectiveness of forest mapping over fragmented landscapes using dense time series of Landsat images. We collected 1548 scenes of Landsat 8 Operational Land Imager (OLI) for the period 2014–2016 and composited them into cloudless mosaics for the following four seasons: yearly, summer, autumn, and April–October. The classification of images was performed in Google Earth Engine (GEE) Application Programming Interface (API) using random forest (RF) classifier. As a result, 30 m spatial resolution forest mask for flatland of Ukraine was created. The user’s and producer’s accuracy were estimated to be 0.910 ± 0.015 and 0.880 ± 0.018, respectively. The total forest area for the flatland Ukraine is 9440.5 ± 239.4 thousand hectares, which is 3% higher than official data. In general, we conclude that the Landsat-derived forest mask performs well over fragmented landscapes if forest cover of the territory is higher than 10–15%.


2014 ◽  
Vol 18 (7) ◽  
pp. 2615-2628 ◽  
Author(s):  
R. Barthel

Abstract. Today there is a great consensus that water resource research needs to become more holistic, integrating perspectives of a large variety of disciplines. Groundwater and surface water (hereafter: GW and SW) are typically identified as different compartments of the hydrological cycle and were traditionally often studied and managed separately. However, despite this separation, these respective fields of study are usually not considered to be different disciplines. They are often seen as different specializations of hydrology with a different focus yet similar theory, concepts, and methodology. The present article discusses how this notion may form a substantial obstacle in the further integration of GW and SW research and management. The article focuses on the regional scale (areas of approximately 103 to 106 km2), which is identified as the scale where integration is most greatly needed, but ironically where the least amount of fully integrated research seems to be undertaken. The state of research on integrating GW and SW research is briefly reviewed and the most essential differences between GW hydrology (or hydrogeology, geohydrology) and SW hydrology are presented. Groundwater recharge and baseflow are used as examples to illustrate different perspectives on similar phenomena that can cause severe misunderstandings and errors in the conceptualization of integration schemes. The fact that integration of GW and SW research on the regional scale necessarily must move beyond the hydrological aspects, by collaborating with the social sciences and increasing the interaction between science and society in general, is also discussed. The typical elements of an ideal interdisciplinary workflow are presented and their relevance with respect to the integration of GW and SW is discussed. The overall conclusions are that GW hydrology and SW hydrogeology study rather different objects of interest, using different types of observation, working on different problem settings. They have thus developed a different theory, methodology and terminology. However, there seems to be a widespread lack of awareness of these differences, which hinders the detection of the existing interdisciplinary aspects of GW and SW integration and consequently the development of a truly unifying interdisciplinary theory and methodology. Thus, despite having the ultimate goal of creating a more holistic approach, we may have to start integration by analyzing potential disciplinary differences. Improved understanding among hydrologists of what interdisciplinary means and how it works is needed. Hydrologists, despite frequently being involved in multidisciplinary projects, are not sufficiently involved in developing interdisciplinary strategies and do usually not regard the process of integration as such as a research topic of its own. There seems to be a general reluctance to apply a (truly) interdisciplinary methodology because this is tedious and few immediate incentives are experienced. The objective of the present opinion paper is to stimulate a discussion rather than to provide recipes on how to integrate GW and SW research or to explain how specific problems of GW–SW interaction should be solved on a technical level. For that purpose it presents complicated topics in a rather simplified, bold way, ignoring to some degree subtleties and potentially controversial issues.


Author(s):  
N. D. Duong

Abstract. Natural forests are a basic component of the earth ecology. It is essential for biodiversity, hydrological cycle regulation and environmental protection. Globally, natural forests are gradually degraded and reduced due to timber logging, conversion to cropland, production forest, commodity trees, and infrastructure development. Decreasing of natural forests results in loss of valuable habitats, land degradation, soil erosion and imbalance of water cycle in regional scale. Thus operational monitoring natural forest cover change, therefore, has been in interest of scientists for long time. Forest cover mapping methods are divided to two groups: field-based survey and remotely sensed image data based techniques. The field-based methods are conventional and they have been used widely in forestry management practice. Satellite-image-based methods were developed since beginning of earth observation. These methods, except visual image interpretation, can be grouped to supervised and unsupervised classification that rely on various algorithm as statistical, clustering or artificial intelligence. However, there is little report about method, which can extract natural forests from generic forest cover. Over the last couple of decades, natural forests have been over-exploited by various reasons. This practice led to urgent need of development of fast, reliable and automated method for mapping natural forests. In this study, a new method for mapping of natural forest by Landsat time series is presented. The new method is fully automated. It uses spectral patterns as principal classifier to recognize land cover classes. The proposed method was applied in study area consisted of Ratanakiri of Cambodia, Attapeu of Laos and Kon Tum of Vietnam. About 2000 Landsat images were used to generate land cover maps of the study area across years from 1989 to 2018.


Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 889 ◽  
Author(s):  
Adrianto ◽  
Spracklen ◽  
Arnold

Forest and peatland fires occur regularly across Indonesia, resulting in large greenhouse gas emissions and causing major air quality issues. Over the last few decades, Indonesia has also experienced extensive forest loss and conversion of natural forest to oil palm and timber plantations. Here we used data on fire hotspots and tree-cover loss, as well as information on the extent of peat land, protected areas, and concessions to explore spatial and temporal relationships among forest, forest loss, and fire frequency. We focus on the Riau Province in Central Sumatra, one of the most active regions of fire in Indonesia. We find strong relationships between forest loss and fire at the local scale. Regions with forest loss experienced six times as many fire hotspots compared to regions with no forest loss. Forest loss and maximum fire frequency occurred within the same year, or one year apart, in 70% of the 1 km2 cells experiencing both forest loss and fire. Frequency of fire was lower both before and after forest loss, suggesting that most fire is associated with the forest loss process. On peat soils, fire frequency was a factor 10 to 100 lower in protected areas and natural forest logging concessions compared to oil palm and wood fiber (timber) concessions. Efforts to reduce fire need to address the underlying role of land-use and land-cover change in the occurrence of fire. Increased support for protected areas and natural forest logging concessions and restoration of degraded peatlands may reduce future fire risk. During times of high fire risk, fire suppression resources should be targeted to regions that are experiencing recent forest loss, as these regions are most likely to experience fire.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Everton B. P. Miranda ◽  
Carlos A. Peres ◽  
Vítor Carvalho-Rocha ◽  
Bruna V. Miguel ◽  
Nickolas Lormand ◽  
...  

AbstractApex predators are threatened globally, and their local extinctions are often driven by failures in sustaining prey acquisition under contexts of severe prey scarcity. The harpy eagle Harpia harpyja is Earth’s largest eagle and the apex aerial predator of Amazonian forests, but no previous study has examined the impact of forest loss on their feeding ecology. We monitored 16 active harpy eagle nests embedded within landscapes that had experienced 0 to 85% of forest loss, and identified 306 captured prey items. Harpy eagles could not switch to open-habitat prey in deforested habitats, and retained a diet based on canopy vertebrates even in deforested landscapes. Feeding rates decreased with forest loss, with three fledged individuals dying of starvation in landscapes that succumbed to 50–70% deforestation. Because landscapes deforested by > 70% supported no nests, and eaglets could not be provisioned to independence within landscapes > 50% forest loss, we established a 50% forest cover threshold for the reproductive viability of harpy eagle pairs. Our scaling-up estimate indicates that 35% of the entire 428,800-km2 Amazonian ‘Arc of Deforestation’ study region cannot support breeding harpy eagle populations. Our results suggest that restoring harpy eagle population viability within highly fragmented forest landscapes critically depends on decisive forest conservation action.


2018 ◽  
pp. 107-130 ◽  
Author(s):  
T. V. Chernenkova ◽  
O. V. Morozova ◽  
N. G. Belyaeva ◽  
M. Yu. Puzachenko

This study aimed at an investigation of the structure, ecology and mapping of mixed communities with the participation of spruce, pine and broad-leave trees in one of the regions of broad-leave–coniferous zone. Despite the long history of the nature use of the study area, including forestry practices (Kurnayev, 1968; Rysin, Saveliyeva, 2007; Arkhipova, 2014; Belyaeva, Popov, 2016), the communities kept the main features of the indigenous forests of the broad-leave–coniferous zone ­— the tree species polydominance of the stands, the multilayer structure of communities and the high species diversity. In the course of field works in the southwestern part of the Moscow Region (2000–2016) 120 relevés were made. Spatial structure, species composition as well as cover values (%) of all vascular plants and bryophytes were recorded in each stand. The relevés were analysed following the ecology-phytocenotic classification approach and methods of multivariate statistical analysis that allowed correctly to differentiate communities according the broad-leave species participation. The accuracy of the classification based on the results of discriminant analysis was 95.8 %. Evaluation of the similarity of the selected units was carried out with the help of cluster analysis (Fig. 12). Clustering into groups is performed according to the activity index of species (A) (Malyshev, 1973) within the allocated syntaxon using Euclidean distance and Ward’s method. The classification results are corrected by DCA ordination in PC-ORD 5.0 (McCune, Mefford, 2006) (Fig. 1). Spatial mapping of forest cover was carried out on the basis of ground data, Landsat satellite images (Landsat 5 TM, 7 ETM +, 8 OLI_TIRS), digital elevation (DEM) and statistical methods (Puzachenko et al., 2014; Chernenkova et al., 2015) (Fig. 13 а, б). The obtained data and the developed classification refine the existing understanding of the phytocenotic structure of the forest cover of the broad-leave–coniferous zone. Three forest formation groups with different shares of broad-leave species in the canopy with seven groups of associations were described: a) coniferous forests with broad-leave species (small- and broad-herb spruce forests with oak and lime (1)); broad-herb spruce forests with oak and lime (2); small- and broad-herb pine forests with spruce, lime, oak and hazel (3); broad-herb pine forests with lime, oak and hazel (4)), b) broad-leave–coniferous forests (broad-herb spruce–broad-leave forests (5)), and c) broad-leave forests (broad-herb oak forests (6), broad-herb lime forests (7)). In the row of discussed syntaxa from 1 to 7 group, the change in the ratio of coniferous and broad-leave species of the tree layer (A) reflects re­gular decrease in the participation of spruce in the plant cover (from 66 to 6 %; Fig. 3 A1, A2) and an increase in oak and lime more than threefold (from 15 to 65 %; Fig. 4 a). Nemoral species predominate in the composition of ground layers, the cove­rage of which increases (from 40 to 80 %) in the range from 1 to 7 group, the coverage of the boreal group varies from 55 to 8 % (Fig. 11) while maintaining the presence of these species, even in nemoral lime and oak forests. In forests with equal share of broad-leave and coniferous trees (group 5) the nemoral species predominate in herb layer. In oak forests (group 6) the species of the nitro group are maximally represented, which is natural for oak forests occurring on rich soils, and also having abundant undergrowth of hazel. Practically in all studied groups the presence of both coniferous (in particular, spruce) and broad-leave trees in undergrowth (B) and ground layer (C) were present in equal proportions (Fig. 3). This does not confirm the unambiguity of the enrichment with nemoral species and increase in their cover in complex spruce and pine forests in connection with the climate warming in this region, but rather indicates on natural change of the main tree species in the cenopopulations. Further development of the stand and the formation of coni­ferous or broad-leave communities is conditioned by landscape. It is proved that the distribution of different types of communities is statistically significant due to the relief. According to the results of the analysis of remote information, the distribution areas of coniferous forests with broad-leave species, mixed and broad-leave forest areas for the study region are represented equally. The largest massifs of broad-leave–coniferous forests are located in the central and western parts of the study area, while in the eastern one the broad-leave forests predominate, that is a confirmation of the zonal ecotone (along the Pakhra River: Petrov, Kuzenkova, 1968) from broad-leave–coniferous forests to broad-leave forests.


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