109,530 research outputs found
Vegetation response to extreme climate events on the Mongolian Plateau from 2000 to 2010
Climate change has led to more frequent extreme winters (aka, dzud) and summer droughts on the Mongolian Plateau during the last decade. Among these events, the 2000–2002 combined summer drought–dzud and 2010 dzud were the most severe on vegetation. We examined the vegetation response to these extremes through the past decade across the Mongolian Plateau as compared to decadal means. We first assessed the severity and extent of drought using the Tropical Rainfall Measuring Mission (TRMM) precipitation data and the Palmer drought severity index (PDSI). We then examined the effects of drought by mapping anomalies in vegetation indices (EVI, EVI2) and land surface temperature derived from MODIS and AVHRR for the period of 2000–2010. We found that the standardized anomalies of vegetation indices exhibited positively skewed frequency distributions in dry years, which were more common for the desert biome than for grasslands. For the desert biome, the dry years (2000–2001, 2005 and 2009) were characterized by negative anomalies with peak values between �1.5 and �0.5 and were statistically different (P \u3c 0:001) from relatively wet years (2003, 2004 and 2007). Conversely, the frequency distributions of the dry years were not statistically different (p \u3c 0:001) from those of the relatively wet years for the grassland biome, showing that they were less responsive to drought and more resilient than the desert biome. We found that the desert biome is more vulnerable to drought than the grassland biome. Spatially averaged EVI was strongly correlated with the proportion of land area affected by drought (PDSI \u3c �1) in Inner Mongolia (IM) and Outer Mongolia (OM), showing that droughts substantially reduced vegetation activity. The correlation was stronger for the desert biome (R2 D 65 and 60, p \u3c 0:05) than for the IM grassland biome (R2 D 53, p \u3c 0:05). Our results showed significant differences in the responses to extreme climatic events (summer drought and dzud) between the desert and grassland biomes on the Plateau
Evolutionary biology and anthropology suggest biome reconstitution as a necessary approach toward dealing with immune disorders
Industrialized society currently faces a wide range of non-infectious, immune-related pandemics. These pandemics include a variety of autoimmune, inflammatory and allergic diseases that are often associated with common environmental triggers and with genetic predisposition, but that do not occur in developing societies. In this review, we briefly present the idea that these pandemics are due to a limited number of evolutionary mismatches, the most damaging being ‘biome depletion’. This particular mismatch involves the loss of species from the ecosystem of the human body, the human biome, many of which have traditionally been classified as parasites, although some may actually be commensal or even mutualistic. This view, evolved from the ‘hygiene hypothesis’, encompasses a broad ecological and evolutionary perspective that considers host-symbiont relations as plastic, changing through ecological space and evolutionary time. Fortunately, this perspective provides a blueprint, termed 'biome reconstitution', for disease treatment and especially for disease prevention. Biome reconstitution includes the controlled and population-wide reintroduction (i.e. domestication) of selected species that have been all but eradicated from the human biome in industrialized society and holds great promise for the elimination of pandemics of allergic, inflammatory and autoimmune diseases
Intensification and Sustainability in South African Rooibos: exploring the conditions for market-led sustainable development in a biodiversity hot spot
The Fynbos biome in the Cape region in South Africa is currently the only production location of Rooibos tea in the world. In addition, biodiversity in the Fynbos biome is very large and unique for the world. This makes Rooibos tea a unique product, the availability of which strongly depends on the dynamics in a bounded territory. Rooibos is sometimes harvested from the wild, but up to 99% of all Rooibos is cultivated. 95% of all Rooibos is produced on large farms or plantations. Such farms, which also exist for potatoes and grapes in the Fynbos biome have a large impact on the ecosystem, especially because large areas have been cleared in the past for their establishment. For instance, ‘an average of 2.7 hectares of virgin land has been cleared for farming every day in the past 15 years’, in the Northern Sandveld
Conservation of the Cerrado from the valorization of socio-biodiversity products: the importance of production chains and local marketing channels
The Cerrado occupies an area of about 20 million km2 (approximately 20% of the Brazilian territory), being the second largest national biome and the richest savanna in biodiversity of the planet. Although it covers three regions of the country (Northeast, Midwest and Southeast) and housing a significant number of traditional communities and family farmers, is the biome with the lowest percentage of protected areas and therefore one of the most threatened. Strategies for the promotion of non-timber forest products (NTFP) for the conservation of the biome and promotion of sustainable development, with job creation and poverty reduction have been implemented. There are several cases in different states, of products with local supply and demand, but, in the meantime, there are fewer cases of large-scale impacts, reaching in more distant markets. Based on field research carried out in the last five years, we present a comparison of cases of promotion of NTFP chains in different regions of the Cerrado, where we highlight experiences and products of greater demand and occurrence, with the cases of Baru (Dipteryx alata), pequi (Caryocar brasiliense) and babassu (Attalea speciosa), which, based on different strategies of market insertion of agro-extractive organizations, promoted important changes in terms of income generation with local communities and conservation of the biome. Other products, such as buriti (Mauritia flexuosa), macaúba (Acrocomia aculeata) and other species of lesser occurrence, although less demanded, contribute to the maintenance of the diversity of forest species and the generation of complementary income to the communities
Application of the biomization technique in the Eastern Colombian Andes
Two pollen records (Lake Fuquene and Pantano de Martos) are analyzed in order to test the usefulness of the Biomization technique to management on forest adaptation to climate change. This work focuses on Biomes and Plant Functional Types response to climate changes on specific dates (18, 14, 12.5, 8 and 6 Kyr) along the Late Quaternary, as deduced from the pollen composition. Results show different responses of vegetation to changes in past environmental conditions, which can be attributed to the different altitudes of the two study sites. While biomes in Lake Fuquene (2500 m a.s.l.) shift from Cool Grassland at 18 Kyr to Cool Mixed Forest and Cool evergreen Forest at 6 Kyr ago, no biome shift is detected in Pantano de Martos (3200 m a.s.l.) through the Late Quaternary. A look to the different Plant Functional Types taking part on the surroundings of the study sites at different ages, together with the analyses of Arboreal / Non Arboreal pollen percentages, give a detailed idea of the ecosystem response to past climate changes. This study shows the potential of the Biomization technique as a simple and powerful tool to analyze ecosystem responses at local and regional scales
Data-based estimates of the ocean carbon sink variability – First results of the Surface Ocean pCO2 Mapping intercomparison (SOCOM)
Using measurements of the surface-ocean CO2 partial pressure (pCO2) and 14 different pCO2 mapping methods recently collated by the Surface Ocean pCO2 Mapping intercomparison (SOCOM) initiative, variations in regional and global sea–air CO2 fluxes are investigated. Though the available mapping methods use widely different approaches, we find relatively consistent estimates of regional pCO2 seasonality, in line with previous estimates. In terms of interannual variability (IAV), all mapping methods estimate the largest variations to occur in the eastern equatorial Pacific. Despite considerable spread in the detailed variations, mapping methods that fit the data more closely also tend to agree more closely with each other in regional averages. Encouragingly, this includes mapping methods belonging to complementary types – taking variability either directly from the pCO2 data or indirectly from driver data via regression. From a weighted ensemble average, we find an IAV amplitude of the global sea–air CO2 flux of 0.31 PgC yr−1 (standard deviation over 1992–2009), which is larger than simulated by biogeochemical process models. From a decadal perspective, the global ocean CO2 uptake is estimated to have gradually increased since about 2000, with little decadal change prior to that. The weighted mean net global ocean CO2 sink estimated by the SOCOM ensemble is −1.75 PgC yr−1 (1992–2009), consistent within uncertainties with estimates from ocean-interior carbon data or atmospheric oxygen trend
Evaluation of MODIS LAI/FPAR product Collection 6. Part 1: consistency and improvements
As the latest version of Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) products, Collection 6 (C6) has been distributed since August 2015. This collection is evaluated in this two-part series with the goal of assessing product accuracy, uncertainty and consistency with the previous version. In this first paper, we compare C6 (MOD15A2H) with Collection 5 (C5) to check for consistency and discuss the scale effects associated with changing spatial resolution between the two collections and benefits from improvements to algorithm inputs. Compared with C5, C6 benefits from two improved inputs: (1) L2G–lite surface reflectance at 500 m resolution in place of reflectance at 1 km resolution; and (2) new multi-year land-cover product at 500 m resolution in place of the 1 km static land-cover product. Global and seasonal comparison between C5 and C6 indicates good continuity and consistency for all biome types. Moreover, inter-annual LAI anomalies at the regional scale from C5 and C6 agree well. The proportion of main radiative transfer algorithm retrievals in C6 increased slightly in most biome types, notably including a 17% improvement in evergreen broadleaf forests. With same biome input, the mean RMSE of LAI and FPAR between C5 and C6 at global scale are 0.29 and 0.091, respectively, but biome type disagreement worsens the consistency (LAI: 0.39, FPAR: 0.102). By quantifying the impact of input changes, we find that the improvements of both land-cover and reflectance products improve LAI/FPAR products. Moreover, we find that spatial scale effects due to a resolution change from 1 km to 500 m do not cause any significant differences.Help from MODIS & VIIRS Science team members is gratefully acknowledged. This work is supported by the MODIS program of NASA and partially funded by the National Basic Research Program of China (Grant No. 2013CB733402), the key program of NSFC (Grant No. 41331171) and Chinese Scholarship Council. (MODIS program of NASA; 2013CB733402 - National Basic Research Program of China; 41331171 - NSFC; Chinese Scholarship Council
Exploring the value of Scotland's environment
Protection of the environment can be regarded as representing a substantial cost to business. However, it is typically considered from the point of view of effect on company profitability, rather than its relative importance to human kind. This paper estimates the value of Scotland's natural environment by applying the methodology developed by Costanza et al (1997a and b) for estimation of the value of the earth's ecosystem services. Ecosystem services provide the vital functions to support life on Earth, such as flows of materials and energy. Since the study's publication, further research has sought to apply this global methodology to a regional and national level (for example Loomis et al, 2000, Farber and Griner, 2000 and Stevens et al, 2000). The value derived for Scotland provides a useful context for understanding the scale and importance of Scotland's natural habitats and it helps to reinforce the message that the environment is central to human welfare (Williams et al, 2003). The valuation of ecosystem services in monetary terms provokes theoretical, practical and philosophical arguments. This paper does not seek to revisit in depth these debates; rather the valuation should be taken as a starting point for setting the importance of Scotland's ecosystems in an interesting perspective. A recent edition of the journal Ecological Economics (Costanza and Farber, 2002) was devoted to considering some of these issues and providing many avenues for further exploration
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Boreal forest CO2 exchange and evapotranspiration predicted by nine ecosystem process models: Intermodel comparisons and relationships to field measurements
Nine ecosystem process models were used to predict CO2 and water vapor exchanges by a 150-year-old black spruce forest in central Canada during 1994–1996 to evaluate and improve the models. Three models had hourly time steps, five had daily time steps, and one had monthly time steps. Model input included site ecosystem characteristics and meteorology. Model predictions were compared to eddy covariance (EC) measurements of whole-ecosystem CO2exchange and evapotranspiration, to chamber measurements of nighttime moss-surface CO2release, and to ground-based estimates of annual gross primary production, net primary production, net ecosystem production (NEP), plant respiration, and decomposition. Model-model differences were apparent for all variables. Model-measurement agreement was good in some cases but poor in others. Modeled annual NEP ranged from −11 g C m−2 (weak CO2source) to 85 g C m−2 (moderate CO2 sink). The models generally predicted greater annual CO2sink activity than measured by EC, a discrepancy consistent with the fact that model parameterizations represented the more productive fraction of the EC tower “footprint.” At hourly to monthly timescales, predictions bracketed EC measurements so median predictions were similar to measurements, but there were quantitatively important model-measurement discrepancies found for all models at subannual timescales. For these models and input data, hourly time steps (and greater complexity) compared to daily time steps tended to improve model-measurement agreement for daily scale CO2 exchange and evapotranspiration (as judged by root-mean-squared error). Model time step and complexity played only small roles in monthly to annual predictions
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