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Ioannis Z Gitas - One of the best experts on this subject based on the ideXlab platform.
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mapping post fire Forest Regeneration and vegetation recovery using a combination of very high spatial resolution and hyperspectral satellite imagery
International Journal of Applied Earth Observation and Geoinformation, 2013Co-Authors: George Mitri, Ioannis Z GitasAbstract:Careful evaluation of Forest Regeneration and vegetation recovery after a fire event provides vital information useful in land management. The use of remotely sensed data is considered to be especially suitable for monitoring ecosystem dynamics after fire. The aim of this work was to map post-fire Forest Regeneration and vegetation recovery on the Mediterranean island of Thasos by using a combination of very high spatial (VHS) resolution (QuickBird) and hyperspectral (EO-1 Hyperion) imagery and by employing object-based image analysis. More specifically, the work focused on (1) the separation and mapping of three major post-fire classes (Forest Regeneration, other vegetation recovery, unburned vegetation) existing within the fire perimeter, and (2) the differentiation and mapping of the two main Forest Regeneration classes, namely, Pinus brutia Regeneration, and Pinus nigra Regeneration. The data used in this study consisted of satellite images and field observations of homogeneous regenerated and revegetated areas. The methodology followed two main steps: a three-level image segmentation, and, a classification of the segmented images. The process resulted in the separation of classes related to the aforementioned objectives. The overall accuracy assessment revealed very promising results (approximately 83.7% overall accuracy, with a Kappa Index of Agreement of 0.79). The achieved accuracy was 8% higher when compared to the results reported in a previous work in which only the EO-1 Hyperion image was employed in order to map the same classes. Some classification confusions involving the classes of P. brutia Regeneration and P. nigra Regeneration were observed. This could be attributed to the absence of large and dense homogeneous areas of regenerated pine trees in the study area.
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mapping postfire vegetation recovery using eo 1 hyperion imagery
IEEE Transactions on Geoscience and Remote Sensing, 2010Co-Authors: George Mitri, Ioannis Z GitasAbstract:The aim of this paper is to investigate whether it is possible to accurately map postfire vegetation recovery on the Mediterranean island of Thasos by employing Earth Observing-1 (EO-1) Hyperion imagery and object-based classification. Specific objectives include the following: 1) locating and mapping areas of Forest Regeneration and other vegetation recovery and distinguishing among them; 2) distinguishing between Pinus brutia Regeneration and Pinus nigra Regeneration within the area of Forest Regeneration; and 3) examining whether it is possible to distinguish between areas of Forest Regeneration (Pinus brutia, Pinus nigra) and mature Forest. The data used in this study consist of satellite images, field-spectroradiometry measurements, and field observations of the homogenous revegetated areas. The methodology comprised four consecutive steps. The first step involved preprocessing of the Hyperion image and field data. Subsequently, an object-oriented model was developed, which involved three steps, namely, image segmentation, object training, and object classification. The process resulted in the separation of five classes (?brutia mature,? ? nigra mature,? ?brutia Regeneration,? ?nigra Regeneration,? and ?other vegetation?). The accuracy assessment revealed very promising results (approximately 75.81% overall accuracy, with a Kappa Index of Agreement of 0.689). Some classification confusion involving the classes of Pinus brutia Regeneration and Pinus nigra Regeneration was recorded. This could be attributed to the absence of large homogenous areas of regenerated pine trees. The main conclusion drawn in this paper was that object-based classification can be used to accurately map postfire vegetation recovery using EO-1 Hyperion imagery.
Frans Bongers - One of the best experts on this subject based on the ideXlab platform.
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natural Forest Regeneration and ecological restoration in human modified tropical landscapes
Biotropica, 2016Co-Authors: Miguel Martinezramos, Aline Pingarroni, Jorge Rodriguezvelazquez, Lilibeth Toledochelala, Isela Zermenohernandez, Frans BongersAbstract:In human-modified tropical landscapes (HMLs) the conservation of biodiversity, functions and services of Forest ecosystems depends on persistence of old growth Forest remnants, Forest Regeneration in abandoned agricultural fields, and restoration of degraded lands. Understanding the impacts of agricultural land uses (ALUs) on Forest Regeneration is critical for biodiversity conservation in HMLs. Here, we develop a conceptual framework that considers the availability of propagules and the environment prevailing after field abandonment as two major determinants of Forest Regeneration in HMLs. The framework proposes that Regeneration potential decreases with size, duration and severity of agricultural disturbance, reducing propagule availability and creating ill-suited environmental conditions for Regeneration. We used studies from Southern Mexico to assess this framework. First, we identify Regeneration bottlenecks that trees face during transit from seed to follow-up life stages, using demographic analysis of dominant pioneer species in recently abandoned fields. Then, we explore effects of ALUs on Forest Regeneration at the field and landscape scales, addressing major legacies. Finally, we integrate agricultural disturbance with landscape composition to predict attributes of successful second growth Forests in HMLs, and provide indicators useful to select tree native species for active restoration. An indicator of disturbance inflicted by ALUs, based on farmers’ information, predicted better Regeneration potential than measurements of soil and microclimate conditions at time of abandonment. Cover of cattle pastures in the landscape was a stronger indicator of Forest regenerating attributes than cover of old growth Forest remnants. To conclude, we offer recommendations to promote Forest Regeneration and biodiversity conservation in HMLs.
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the ecology of lianas and their role in Forests
Trends in Ecology and Evolution, 2002Co-Authors: Stefan A Schnitzer, Frans BongersAbstract:Recent studies have demonstrated the increasingly important role of lianas (woody vines) in Forest Regeneration, species diversity and ecosystem-level processes, particularly in the tropics. Mechanisms responsible for the maintenance of liana species diversity could yield new insights into the maintenance of overall species diversity. Lianas contribute to Forest Regeneration and competition, not only by competing directly with trees, but also by differentially affecting tree species and thus changing how trees compete among themselves. In addition, they contribute considerably to ecosystem-level processes, such as whole-Forest transpiration and carbon sequestration. As the rate of tropical Forest disturbance increases, they are likely to increase in relative abundance throughout the tropics and the importance of lianas to many aspects of Forest dynamics will grow.
Marcelo Tabarelli - One of the best experts on this subject based on the ideXlab platform.
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resprouting drives successional pathways and the resilience of caatinga dry Forest in human modified landscapes
Forest Ecology and Management, 2021Co-Authors: Maria Fabiola Barros, Elâine M S Ribeiro, Renato Soares Vanderlei, Alexandre Souza De Paula, Ana Beatriz Silva, Rainer Wirth, Marcus Vinicius Cianciaruso, Marcelo TabarelliAbstract:Abstract Tropical Forest Regeneration has gained renewed interest in recent years as secondary Forests have being considered biodiversity repositories and a key source for globally relevant ecosystem services as climate regulation and carbon sequestration and storage. Here, we address the Regeneration of a Caatinga dry Forest in the context of slash-and-burn agriculture and chronic anthropogenic disturbance by examining Forest Regeneration mechanisms and a comprehensive set of community-level plant diversity measures (i.e., taxonomic, functional, and phylogenetic) in regenerating (4 to 70-yr old) and old-growth Forest stands. Resprouting from root suckers was the predominant Regeneration mechanism across recently abandoned crop fields. Overall, regenerating Forests were similar to old-growth Forests in terms of taxonomic and functional composition, and functional and phylogenetic diversity. Moreover, except for the taxonomic diversity, community-level plant diversity measures were not related to Forest age or soil properties. Our results suggest that Caatinga dry Forest covering sandy soils is particularly resilient due to Regeneration driven by resprouting. The same set of plant species dominates the entire Regeneration process, including old-growth Forest stands. Accordingly, Caatinga dry Forest Regeneration may follow an initial composition model, rather than following a directional and deterministic trajectory associated with species replacements. This initial composition model probably results from a combination of three factors: (1) early Regeneration driven by resprouting rather than seed arrival and seedling recruitment; (2) biomass accumulation mostly due to growth by early colonizers and by those species able to resprout after chronic anthropogenic disturbance and during Forest Regeneration; and (3) the co-occurrence of functionally distinct plant species. Accordingly, resprouting can guarantee some level of resilience, and hence, the services provided by secondary Forests. Nevertheless, Forest dynamics in landscapes inhabited by Forest-dependent people are affected to a great extent by the nature of the imposed pressures and the ecological profile of the remaining flora.
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abiotic and vertebrate seed dispersal in the brazilian atlantic Forest implications for Forest Regeneration
Biological Conservation, 2002Co-Authors: Marcelo Tabarelli, Carlos A PeresAbstract:This study documents the proportion of woody plant species having different modes of seed dispersal, and classes of seed and fruit size at 16 Atlantic montane Forest plots of southeastern Brazil (23–24 � S). These plots represent six chronosequences (from 5year-old to old-growth Forest) of Forest Regeneration following small-scale shifting agriculture. Our results indicate that there is a gradual but predictable increase in the number of woody plant species relying on vertebrate-mediated seed dispersal in increasingly older plots. Moreover, the percentage of plant species bearing small seeds and fruits ( < 0.6 cm in length) was more than halved from earlier to older Forest plots, while the percentage of plant species producing middle-sized seeds and fruits at least doubled. Plant species belonging to the Melastomataceae, Myrsinaceae, Rubiaceae and Flacourtiaceae comprised a large proportion of the small-seeded and fruit species (33–53%), and largely occurred in early successional Forest plots (5–30 years old). In contrast, species belonging to the Myrtaceae and Lauraceae represented most of the species (51–72%) bearing medium-sized seeds and fruits (0.6–1.5 cm in length), and occurred primarily in the old-growth Forests. Shifts in the relative importance of dispersal strategies during the Regeneration process of Atlantic montane Forest, as well as in diaspore size appear to be related to the balance between early successional and shade-tolerant species associated with particular life forms and plant families. Finally, we discuss the relationships between the species richness of Myrtaceae and Lauraceae trees, seed dispersal by medium to large vertebrates, and possible Regeneration scenarios for the Atlantic Forest. # 2002 Elsevier Science Ltd. All rights reserved.
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the soil seed bank during atlantic Forest Regeneration in southeast brazil
Brazilian Journal of Biology, 2001Co-Authors: Claudia Baider, Marcelo Tabarelli, Waldir MantovaniAbstract:A survey was conducted to determine the density and species composition of viable seeds buried in four stands of a tropical montane Forest at Parque Estadual Intervales, Brazil. The objective was to understand: (1) how numbers and composition of the soil seed bank change as the Forest regrows, and (2) how such changes affect the species available for Regeneration if Forests of different ages are cut down. In each Forest stand (5, 18, 27-yr-old and a mature Forest), 57 soil samples were collected (0-2.5 and 2.5-5 cm deep). Viable seed density of herbaceous species ranged between 11,003 seeds. m-2 (5-yr-old vegetation) and 482 (mature Forest), and between 25 (5-yr-old vegetation) and 389 seeds. m-2 (mature Forest) for woody plant species in the 0-5 cm soil layer, suggesting a decrease in seed stocks in the course of Forest Regeneration. Seeds buried in the 0-2.5 cm soil layer represented between 56.9% and 67.4% of all viable seeds. Most of the viable seeds belonged to weeds of Asteraceae, Poaceae, Malvaceae and Solanaceae. The results provide evidence that, in Forests of different ages, the soil does not store seeds of the same key ecological groups involved in the Regeneration of Atlantic Forest. Allochthonous seeds from remaining patches of Forest, as well as their vertebrate dispersers, are needed for Forest Regeneration since the soil seed bank does not store large seeds of shade-tolerant species.
George Mitri - One of the best experts on this subject based on the ideXlab platform.
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mapping post fire Forest Regeneration and vegetation recovery using a combination of very high spatial resolution and hyperspectral satellite imagery
International Journal of Applied Earth Observation and Geoinformation, 2013Co-Authors: George Mitri, Ioannis Z GitasAbstract:Careful evaluation of Forest Regeneration and vegetation recovery after a fire event provides vital information useful in land management. The use of remotely sensed data is considered to be especially suitable for monitoring ecosystem dynamics after fire. The aim of this work was to map post-fire Forest Regeneration and vegetation recovery on the Mediterranean island of Thasos by using a combination of very high spatial (VHS) resolution (QuickBird) and hyperspectral (EO-1 Hyperion) imagery and by employing object-based image analysis. More specifically, the work focused on (1) the separation and mapping of three major post-fire classes (Forest Regeneration, other vegetation recovery, unburned vegetation) existing within the fire perimeter, and (2) the differentiation and mapping of the two main Forest Regeneration classes, namely, Pinus brutia Regeneration, and Pinus nigra Regeneration. The data used in this study consisted of satellite images and field observations of homogeneous regenerated and revegetated areas. The methodology followed two main steps: a three-level image segmentation, and, a classification of the segmented images. The process resulted in the separation of classes related to the aforementioned objectives. The overall accuracy assessment revealed very promising results (approximately 83.7% overall accuracy, with a Kappa Index of Agreement of 0.79). The achieved accuracy was 8% higher when compared to the results reported in a previous work in which only the EO-1 Hyperion image was employed in order to map the same classes. Some classification confusions involving the classes of P. brutia Regeneration and P. nigra Regeneration were observed. This could be attributed to the absence of large and dense homogeneous areas of regenerated pine trees in the study area.
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mapping postfire vegetation recovery using eo 1 hyperion imagery
IEEE Transactions on Geoscience and Remote Sensing, 2010Co-Authors: George Mitri, Ioannis Z GitasAbstract:The aim of this paper is to investigate whether it is possible to accurately map postfire vegetation recovery on the Mediterranean island of Thasos by employing Earth Observing-1 (EO-1) Hyperion imagery and object-based classification. Specific objectives include the following: 1) locating and mapping areas of Forest Regeneration and other vegetation recovery and distinguishing among them; 2) distinguishing between Pinus brutia Regeneration and Pinus nigra Regeneration within the area of Forest Regeneration; and 3) examining whether it is possible to distinguish between areas of Forest Regeneration (Pinus brutia, Pinus nigra) and mature Forest. The data used in this study consist of satellite images, field-spectroradiometry measurements, and field observations of the homogenous revegetated areas. The methodology comprised four consecutive steps. The first step involved preprocessing of the Hyperion image and field data. Subsequently, an object-oriented model was developed, which involved three steps, namely, image segmentation, object training, and object classification. The process resulted in the separation of five classes (?brutia mature,? ? nigra mature,? ?brutia Regeneration,? ?nigra Regeneration,? and ?other vegetation?). The accuracy assessment revealed very promising results (approximately 75.81% overall accuracy, with a Kappa Index of Agreement of 0.689). Some classification confusion involving the classes of Pinus brutia Regeneration and Pinus nigra Regeneration was recorded. This could be attributed to the absence of large homogenous areas of regenerated pine trees. The main conclusion drawn in this paper was that object-based classification can be used to accurately map postfire vegetation recovery using EO-1 Hyperion imagery.
Robert R Dunn - One of the best experts on this subject based on the ideXlab platform.
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recovery of faunal communities during tropical Forest Regeneration
Conservation Biology, 2004Co-Authors: Robert R DunnAbstract:As mature tropical Forests are cleared, secondary Forests may play an important role in the con- servation of animal species, depending on how fast animal communities recover during Forest Regeneration. I reviewed published studies on the recovery of animal species richness and composition during tropical Forest Regeneration. In 38 of the 39 data sets I examined, conversion of Forest to agriculture or pasture substantially reduced species richness. Given suitable conditions for Forest recovery, the species richness of the animal taxa considered can be predicted to resemble that of mature Forests roughly 20-40 years after land abandonment. At least for ants and birds, however, recovery of species composition appears to take substantially longer than recovery of species richness. Because species richness for many taxa appears to recover relatively rapidly in secondary Forests, conservation of secondary Forests may be an effective investment in future diversity. The slower recovery of species composition indicates, however, that some species will require stands of mature Forest to persist.