Carbon Dynamics in a Seasonally Dry Tropical Forest PDF Download

Author: Rodrigo Vargas Ramos
Publisher:
ISBN:
Category : Forest biomass
Languages : en
Pages : 368

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Author: Rodolfo Dirzo
Publisher: Island Press
ISBN: 1610910214
Category : Science
Languages : en
Pages : 409

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Book Description
Though seasonally dry tropical forests are equally as important to global biodiversity as tropical rainforests, and are one of the most representative and highly endangered ecosystems in Latin America, knowledge about them remains limited because of the relative paucity of attention paid to them by scientists and researchers and a lack of published information on the subject. Seasonally Dry Tropical Forests seeks to address this shortcoming by bringing together a range of experts in diverse fields including biology, ecology, biogeography, and biogeochemistry, to review, synthesize, and explain the current state of our collective knowledge on the ecology and conservation of seasonally dry tropical forests. The book offers a synthetic and cross-disciplinary review of recent work with an expansive scope, including sections on distribution, diversity, ecosystem function, and human impacts. Throughout, contributors emphasize conservation issues, particularly emerging threats and promising solutions, with key chapters on climate change, fragmentation, restoration, ecosystem services, and sustainable use. Seasonally dry tropical forests are extremely rich in biodiversity, and are seriously threatened. They represent scientific terrain that is poorly explored, and there is an urgent need for increased understanding of the system's basic ecology. Seasonally Dry Tropical Forests represents an important step in bringing together the most current scientific information about this vital ecosystem and disseminating it to the scientific and conservation communities.

Author: R. K. Chaturvedi
Publisher:
ISBN: 9781536195439
Category :
Languages : en
Pages :

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Book Description
Tropical dry forests (TDFs) constitute one of the most dominant forests, accounting for approximately 45% of all tropical forests. These forests are distributed over an extensive geographical range, spanning large areas of Africa, Latin America, and the Asia Pacific. TDFs occur in severe and extremely variable climate characterized by low annual rainfall and 5-6 months of the dry period within the annual cycle, and nutrient-poor soil. Due to extreme drought conditions, TDFs exhibit deciduousness and various other adaptative features (viz., fire resistance, desiccation tolerance, herbivore defence, high root:shoot ratio, longer seed viability) to establish in the severe environmental conditions, which makes these forests exceptionally critical. These forests are one of the most productive with high biodiversity, but unfortunately, due to persistent anthropogenic pressures in terms of burning, mining, indiscriminate forest cutting, lopping, and increased extraction of non-wood forest products, these forest communities have become one of the most endangered ecosystems. Disturbances in TDFs have resulted in fragmentation and ecosystem conversion, and therefore, these forests exhibit changes in their biomass and productivity. Anthropogenic pressure is rapidly becoming a growing concern globally due to its negative impacts on the structure and composition of the vegetation. In addition, due to their higher net primary productivity, these forests have a considerable effect on the global carbon cycle. Uncontrolled harvesting for gaining temporal benefits is a major cause of forest destruction and deforestation which may lead to major loss. Deforestation and clearing of forests have resulted in soil erosion, soil degradation and loss of biodiversity, socio-economic damages to food components, water and health, as well as the loss of people's cultural ethnicity. In order to assess the conservation status of TDFs, information is required on its distribution pattern, climate, structural and functional traits of the vegetation, phenology, strategies against drought, nutrient deficiency, and disturbances. This book discusses various issues, obstacles and opportunities for protection, regeneration and management of TDFs worldwide, as well as information gaps in the areas referred to above, which may be of critical significance in adapting and mitigating responses to the current climate change scenario. The book is intended to help in collection of detailed knowledge and to address the concerns from environmental scientists, forestry experts, planners, policymakers and the general public. Starting with a description of plant composition of worldwide TDFs, the book evaluates plant diversity, biomass dynamics, carbon storage, late history and current status of anthropogenic disturbances, distribution pattern of lichen communities, relevance of tree crown architecture, effects of forestry management practices, degradation and traditional land-use practices, impact of changing environment on carbon dynamics, estimating ecosystem services using a geospatial approach, productivity and carbon accumulation, habitat heterogeneity and its impact on organic matter, nutrient pool and nitrogen mineralization, phosphorus and litter decomposability traits. For re-development of TDFs, the book describes improved low-input tree establishment methods, impact of drought and plant mechanisms to mitigate drought stress, importance of serotiny related to delayed seed dispersal, and foraging efficiency of fine roots in relation to carbon dynamics in a changing environment.

Author: Stephen H. Bullock
Publisher: Cambridge University Press
ISBN: 9780521112840
Category : Science
Languages : en
Pages : 0

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Book Description
Prolonged seasonal drought affects most of the tropics, including vast areas presently or recently dominated by 'dry forests'. These forests have received scant attention, despite the fact that humans have used and changed them more than rain forests. This volume reviews the available information, often making contrasts with wetter forests. The world's dry forest heterogeneity of structure and function is shown regionally. In the neotropics, biogeographic patterns differ from those of wet forests, as does the spectrum of plant life-forms in terms of structure, physiology, phenology and reproduction. Biomass distribution, nutrient cycling, below-ground dynamics and nitrogen gas emission are also reviewed. Exploitation schemes are surveyed, and examples are given of non-timber product economies. It is hoped that this review will stimulate research leading to more conservative and productive management of dry forests.

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721785124
Category :
Languages : en
Pages : 34

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The overall goals of CD-08 team in Phase I were to quantify the contributions of different components of the carbon cycle to overall ecosystem carbon balance in Amazonian tropical forests and to undertake process studies at a number of sites along the eastern LBA transect to understand how and why these fluxes vary with site, season, and year. We divided this work into a number of specific tasks: (1) determining the average rate (and variability) of tree growth over the past 3 decades; (2) determining age demographics of tree populations, using radiocarbon to determine tree age; (3) assessing the rate of production and decomposition of dead wood debris; (4) determining turnover rates for organic matter in soils and the mean age of C respired from soil using radiocarbon measurements; and (5) comparing our results with models and constructing models to predict the potential of tropical forests to function as sources or sinks of C. This report summarizes the considerable progress made towards our original goals, which have led to increased understanding of the potential for central Amazon forests to act as sources or sinks of carbon with altered productivity. The overall picture of tropical forest C dynamics emerging from our Phase I studies suggests that the fraction of gross primary production allocated to growth in these forests is only 25-30%, as opposed to the 50% assumed by many ecosystem models. Consequent slow tree growth rates mean greater mean tree age for a given diameter, as reflected in our measurements and models of tree age. Radiocarbon measurements in leaf and root litter suggest that carbon stays in living tree biomass for several years up to a decade before being added to soils, where decomposition is rapid. The time lags predicted from 14C, when coupled with climate variation on similar time scales, can lead to significant interannual variation in net ecosystem C exchange. Trumbore, Susan and Chambers, Jeffrey Q. and Camargo, Plinio and Martinelli, L

Author: Carlos Alberto Sierra
Publisher:
ISBN:
Category : Carbon cycle (Biogeochemistry)
Languages : en
Pages : 304

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Book Description
Despite the importance of tropical forest ecosystems in the global carbon cycle, there have been few studies of carbon dynamics in this biome. The magnitude of carbon stocks in the tropics and their changes over time are poorly known since ground-based observations are lacking. In this study, total carbon stocks (TCS) and net ecosystem production (NEP) were quantified for tropical forests of the Porce region of Colombia. A modeling exercise was also performed to analyze the effects of population and community processes on carbon dynamics at the ecosystem level. A set of 110 permanent plots were used to estimate TCS and its uncertainty in primary and secondary forests. In primary forests, mean TCS were estimated to be 383.7 ± 43.0 Mg C ha-1 (± standard error). Of this amount, soil organic carbon to 4 m depth represented 59%, total aboveground biomass 29%, total belowground biomass 10%, and necromass 2%. In secondary forests, TCS was 228.2 ± 11.5 Mg C ha-1. Of this store, soil organic carbon to 4 m depth accounted for 84%, total aboveground biomass represented only 9%, total belowground biomass 5%, and total necromass 1%. Based on the uncertainty analysis of TCS estimates, the variability associated with the spatial variation of C pools between plots was higher than measurement errors within plots. A larger variability was observed in primary than in secondary forests and this difference might be explained by gap dynamics. Net ecosystem production was measured in primary forests in a set of 33 permanent plots from 2000 to 2002 in two, one-year intervals. Uncertainty analysis indicated that NEP ranged between -4.03 and 2.22 Mg C ha-1 yr-1 for the two intervals. This range was compared to a priori defined range of natural variation ( -1.5 and 1.5 Mg C ha-1 yr-1) estimated from the ecosystem model STANDCARB. The observed variation in NEP did not provide sufficient evidence to reject the hypothesis that the ecosystem was within its expected natural range. Simulations using the STANDCARB model showed that at the population level, the processes of colonization and mortality can limit the maximum biomass achieved during a successional sequence. Colonization can introduce lags during the initiation of succession and mortality can have important effects on annual variation in carbon stores. Community dynamics, defined as the replacement of species during succession, altered the mixture of species over time. When species had different ecosystem parameters, such as growth and mortality rates, community dynamics caused non-linear patterns of carbon accumulation. These patterns could not be reproduced using a single species with the average of parameters of a multi-species simulation or by using the more abundant species in the simulations.

Author: J S Singh
Publisher:
ISBN: 9789811072611
Category :
Languages : en
Pages : 254

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Book Description
Tropical dry deciduous forests (TDFs) can be found in severe and extremely variable climates characterized by low annual rainfall, 5-6 dry months within the annual cycle, and nutrient-poor soil. Several terms have been used for this vegetation type such as seasonally dry tropical forest (SDTF), tropical dry deciduous forest, monsoon forest, caatinga, cuabal, etc. More than any other factor, the lack of precipitation during a prolonged portion of the year is what produces true dry forest, an ecosystem type characterized by plants and animals with specific adaptations to survive the long dry season. Deciduousness is the single most important adaptation among plants to the extended droughts. Most of the trees drop their leaves after the rains end, and essentially halt photosynthesis, as they would otherwise be unable to survive the water loss during the dry season. TDFs are subject to intensive anthropogenic disturbances and are among the most at-risk ecosystems in the world. In order to assess the conservation status of this forest type, information is required on its distribution pattern, climate, the structure and functional traits of its vegetation, phenology, strategies for coping with drought and nutrient poverty, and disturbances and their effects. In this book, we review important studies on TDFs around the globe, particularly those in the northern dry deciduous forests of India. We put forward the claim that those TDFs that experience drought and arise on nutrient-poor sites feature adaptations such as deciduousness, as well as a variety of nutrient conservation strategies. They also experience biotic disturbances, which can result in fragmentation and ecosystem conversion, and therefore exhibit changes in biomass, productivity, and soil microbial biomass, etc.

Author: Arturo Sanchez-Azofeifa
Publisher: CRC Press
ISBN: 1466512008
Category : Nature
Languages : en
Pages : 566

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Book Description
Under threat from natural and human disturbance, tropical dry forests are the most endangered ecosystem in the tropics, yet they rarely receive the scientific or conservation attention they deserve. In a comprehensive overview, Tropical Dry Forests in the Americas: Ecology, Conservation, and Management examines new approaches for data sampling and analysis using remote sensing technology, discusses new ecological and econometric methods, and critically evaluates the socio-economic pressures that these forest are facing at the continental and national levels. The book includes studies from Mexico, Costa Rica, Colombia, Venezuela, and Brazil that provide in-depth knowledge about the function, status, and conservation efforts of these endangered forests. It presents key elements of synthesis from standardized work conducted across all sites. This unique contribution provides new light in terms of these forests compared to each other not only from an ecological perspective but also in terms of the pressures that they are facing, and their respective responses. Written by experts from a diversity of fields, this reference brings together the many facets of function, use, heritage, and future potential of these forests. It presents an important and exciting synthesis of many years of work across countries, disciplines, and cultures. By standardizing approaches for data sampling and analysis, the book gives readers comparison information that cannot be found anywhere else given the high level of disparity that exists in the current literature.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Abstract : Tropical forests play an important role in the global carbon cycle, but are threatened by human activities, particularly selective logging, which is projected to increase in extent and intensity due to the demands of a rapidly growing human population. Yet, the impacts of selective harvest on carbon dynamics of residual forests is poorly understood. This dissertation examines the effects of selective harvest involving twice the standard logging intensity in Ghana (6.5 vs. 2 to 3 trees ha−1) on aboveground biomass (AGB) and soil respiration in pre- and post-logging forest stands of a moist semi-deciduous forest in Ghana. Using standardized protocols, data were collected in one-hectare plots to observe variation in AGB and soil respiration before and after selective harvest. Prior to logging, AGB was 318.6 Mg ha−1. However, one year after the removal of 121.6 m3 ha−1 of timber trees, AGB declined by 16.9%. Variation in AGB both before and after logging was better explained by species dominance and functional diversity than by species richness. In particular, the dominance of certain species influenced carbon storage before and after logging, due, in part, to environmental filtering of species based on plant functional types and/or life form. While C storage in trees was associated with LAI before logging, LAI was most important for liana C storage after logging. There were significant differences (P ≤ 0.05) in seasonal variation of soil respiration before and after logging, and between a 10- and 20-year post-logging stands with soil respiration higher in the wet season. Similarly, there were significant differences (P ≤ 0.05) in seasonal variation among components of soil respiration in the 10- and 20-year post-logging stands. Autotrophic soil respiration was 33% higher in the 20-year post-logging stand while heterotrophic soil respiration remained similar between the two stands. In general, soil moisture was the most important factor influencing soil respiration across the post-logging stands and for components of soil respiration, particularly root and mycorrhizal respiration. This information about patterns and underlying controls on soil respiration from different soil components should aid attempts to accurately model soil respiration over space and time.

Author: Gordon H. Orians
Publisher: Springer Science & Business Media
ISBN: 3642797555
Category : Science
Languages : en
Pages : 237

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Book Description
Although biologists have directed much attention to estimating the extent and causes of species losses, the consequences for ecosystem functioning have been little studied. This book examines the impact of biodiversity on ecosystem processes in tropical forests - one of the most species-rich and at the same time most endangered ecosystems on earth. It covers the relationships between biodiversity and primary production, secondary production, biogeochemical cycles, soil processes, plant life forms, responses to disturbance, and resistance to invasion. The analyses focus on the key ecological interfaces where the loss of keystone species is most likely to influence the rate and stability of ecosystem processes.