Biome

About: Biome is a research topic. Over the lifetime, 3063 publications have been published within this topic receiving 163208 citations. The topic is also known as: bioms & bioformation.

Global biodiversity scenarios for the year 2100.

Abstract: Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.

A global analysis of root distributions for terrestrial biomes

Abstract: Understanding and predicting ecosystem functioning (e.g., carbon and water fluxes) and the role of soils in carbon storage requires an accurate assessment of plant rooting distributions. Here, in a comprehensive literature synthesis, we analyze rooting patterns for terrestrial biomes and compare distributions for various plant functional groups. We compiled a database of 250 root studies, subdividing suitable results into 11 biomes, and fitted the depth coefficient β to the data for each biome (Gale and Grigal 1987). β is a simple numerical index of rooting distribution based on the asymptotic equation Y=1-βd, where d = depth and Y = the proportion of roots from the surface to depth d. High values of β correspond to a greater proportion of roots with depth. Tundra, boreal forest, and temperate grasslands showed the shallowest rooting profiles (β=0.913, 0.943, and 0.943, respectively), with 80-90% of roots in the top 30 cm of soil; deserts and temperate coniferous forests showed the deepest profiles (β=0.975 and 0.976, respectively) and had only 50% of their roots in the upper 30 cm. Standing root biomass varied by over an order of magnitude across biomes, from approximately 0.2 to 5 kg m-2. Tropical evergreen forests had the highest root biomass (5 kg m-2), but other forest biomes and sclerophyllous shrublands were of similar magnitude. Root biomass for croplands, deserts, tundra and grasslands was below 1.5 kg m-2. Root/shoot (R/S) ratios were highest for tundra, grasslands, and cold deserts (ranging from 4 to 7); forest ecosystems and croplands had the lowest R/S ratios (approximately 0.1 to 0.5). Comparing data across biomes for plant functional groups, grasses had 44% of their roots in the top 10 cm of soil. (β=0.952), while shrubs had only 21% in the same depth increment (β=0.978). The rooting distribution of all temperate and tropical trees was β=0.970 with 26% of roots in the top 10 cm and 60% in the top 30 cm. Overall, the globally averaged root distribution for all ecosystems was β=0.966 (r 2=0.89) with approximately 30%, 50%, and 75% of roots in the top 10 cm, 20 cm, and 40 cm, respectively. We discuss the merits and possible shortcomings of our analysis in the context of root biomass and root functioning.

Ecological Geography of the Sea

Abstract: Preface. Introduction: The Inadequacy of Classical Biogeography in Ecological Analysis. The New Availability of Timely, Global Oceanographic Data. The Use of CZCS Images in This Study. The Choice of Schemes to Partition the Pelagic Ecology of the Oceans. Ecological Gradients: Fronts and the Pycnocline: Oceanic and Shelf Sea Fronts Are Ecotones and Leaky. The Ubiquitous Horizontal "Front" at Shallow Pycnocline. Biogeography of the Shallow Pycnocline: Both Habitat and Boundary. Physical Forcing of Biological Processes: Minimal Set of Predictive Factors for Ecology of the Pelagos. What Do We Really Mean by an Algal Bloom? Can We Specify Major Biomes in the Pelagos? Stratification and Mixing in the Open Ocean: The Consequence of Latitude. Regional Discontinuities in Resistance to Vertical Mixing in the Warm Oceans. The Limits of the Characteristic Conditions of Polar Seas. The Seaward Boundary of Processes along Ocean Margins. Conclusion: there Are Four Primary Biomes in the Ocean. Biomes: Primary Compartments in Ecological Oceanography: A Definition of the Primary Biomes. Polar Biome. Westerlies Biome. Trades Biome. Coastal Boundary Zone Biome. Exceptional Regions: Boundary Layers and the High-Nutrient, Low-Chlorophyll Areas. Oceans, Seas and Provinces: The Secondary Compartments: How to Group the Major Oceans, the Marginal Seas and Coastal Regions. A Method for Specifying Ecological Provinces in the Oceans. A Statistical Test of the Proposed Boundaries. Temporal Variability and the Adjustment of Boundaries: Scales of External Forcing: From Seasons to Centuries. Linking Seasonal to ENSO-Scale Events. Longer Scale Trends and Changes. Conclusion: A Map of Provinces for a Strong ENSO Event? The Atlantic Ocean: Atlantic Polar Biome. Atlantic Westerly Winds Biome. Atlantic Trade Wind Biome. Atlantic Coastal Biome. The Indian Ocean: Indian Ocean Trade Wind Biome. Indian Ocean Coastal Biome. The Pacific Ocean: Pacific Polar Biome. Pacific Westerly Winds Biome. Pacific Trade Wind Biome. Pacific Coastal Biome. The Southern Ocean: Antarctic Westerly Winds Biome. Antarctic Polar Biome. Bibliography. Index.

From tropics to tundra: global convergence in plant functioning

Abstract: Despite striking differences in climate, soils, and evolutionary history among diverse biomes ranging from tropical and temperate forests to alpine tundra and desert, we found similar interspecific relationships among leaf structure and function and plant growth in all biomes. Our results thus demonstrate convergent evolution and global generality in plant functioning, despite the enormous diversity of plant species and biomes. For 280 plant species from two global data sets, we found that potential carbon gain (photosynthesis) and carbon loss (respiration) increase in similar proportion with decreasing leaf life-span, increasing leaf nitrogen concentration, and increasing leaf surface area-to-mass ratio. Productivity of individual plants and of leaves in vegetation canopies also changes in constant proportion to leaf life-span and surface area-to-mass ratio. These global plant functional relationships have significant implications for global scale modeling of vegetation–atmosphere CO2 exchange.

A global biome model based on plant physiology and dominance, soil properties and climate

Abstract: A model to predict global patterns in vegetation physiognomy was developed from physiological considera- tions influencing the distributions of different functional types of plant. Primary driving variables are mean coldest- month temperature, annual accumulated temeprature over 5"C, and a drought index incorporating the seasonality of precipitation and the available water capacity of the soil. The model predicts which plant types can occur in a given environment, and selects the potentially dominant types from among them. Biomes arise as combinations of domi- nant types. Global environmental data were supplied as monthly means of temperature, precipitation and sunshine (interpolated to a global 0.5" grid, with a lapse-rate correc-