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Ecosystem

About: Ecosystem is a research topic. Over the lifetime, 25460 publications have been published within this topic receiving 1291375 citations. The topic is also known as: ecological system & Ecosystem.


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Book
01 Oct 1996
TL;DR: This book discusses plant strategies and successional change: a resource-response perspective, the implications of migration, extinction, and adaptation, and the trends of dominance and diversity in recovering ecosystems.
Abstract: 1. Introduction and background 2. Plant strategies and successional change: a resource-response perspective 3. Community composition and trends of dominance and diversity in recovering ecosystems 4. The environment of successional plants: disentangling causes and consequences 5. Recruitment in successional habitats: general trends and specific differences 6. How do plants interact with each other? 7. Plant/plant interactions and ecosystem recovery 8. Competition and the evolution of response breadths and niches 9. Ecological and genetic variation in early successional plants 10. Coping with a variable environment: habitat selection, response flexibility: tracking, acclimation, and plasticity 11. Physiological trends of plant in recovering ecosystems 12. Crossing the scales: can we predict community composition from individual species response? 13. From fields to forests: forest dynamics and regeneration in a changing environment 14. Succession and global change: the implications of migration, extinction, and adaptation References Index.

600 citations

Journal ArticleDOI
07 Apr 2011-Nature
TL;DR: Results provide direct evidence that communities with more species take greater advantage of the niche opportunities in an environment, and this allows diverse systems to capture a greater proportion of biologically available resources such as nitrogen.
Abstract: Studies in recent years have suggested that the conservation of biodiversity improves the ability of an ecosystem to retain nutrients and remain productive. These papers have proved controversial, in part because of a lack of direct evidence for a mechanism to explain the phenomenon. Now, in experiments involving manipulation of the number of algal species in model stream systems, Bradley Cardinale provides one such mechanism. Uptake of nitrogen nutrients increased linearly with species richness in response to changes in flow habitats and disturbance regimes. But when niche structure was experimentally removed, the relationship disappeared. This suggests that habitats with more species take greater advantage of the niche opportunities in an environment than do less-species-rich habitats, allowing the more diverse systems to capture a greater fraction of biologically active resources such as nitrogen. More diverse stream communities have increased uptake of nutrients, including nitrate, a major pollutant, but the mechanism is little understood. This study manipulated algal species diversity in stream mesocosms with different flow habitats and disturbance regimes. Nitrogen uptake increased linearly with species richness, but when niche structure was experimentally removed the relationship disappeared. Excessive nutrient loading of water bodies is a leading cause of water pollution worldwide1,2, and controlling nutrient levels in watersheds is a primary objective of most environmental policy3. Over the past two decades, much research has shown that ecosystems with more species are more efficient at removing nutrients from soil and water than are ecosystems with fewer species4,5,6,7. This has led some to suggest that conservation of biodiversity might be a useful tool for managing nutrient uptake and storage7,8,9,10, but this suggestion has been controversial, in part because the specific biological mechanisms by which species diversity influences nutrient uptake have not been identified10,11,12. Here I use a model system of stream biofilms to show that niche partitioning among species of algae can increase the uptake and storage of nitrate, a nutrient pollutant of global concern. I manipulated the number of species of algae growing in the biofilms of 150 stream mesocosms that had been set up to mimic the variety of flow habitats and disturbance regimes that are typical of natural streams. Nitrogen uptake rates, as measured by using 15N-labelled nitrate, increased linearly with species richness and were driven by niche differences among species. As different forms of algae came to dominate each unique habitat in a stream, the more diverse communities achieved a higher biomass and greater 15N uptake. When these niche opportunities were experimentally removed by making all of the habitats in a stream uniform, diversity did not influence nitrogen uptake, and biofilms collapsed to a single dominant species. These results provide direct evidence that communities with more species take greater advantage of the niche opportunities in an environment, and this allows diverse systems to capture a greater proportion of biologically available resources such as nitrogen. One implication is that biodiversity may help to buffer natural ecosystems against the ecological impacts of nutrient pollution.

600 citations

Journal ArticleDOI
02 Nov 2000-Nature
TL;DR: Using free-air CO2 enrichment (FACE) technology in an intact Mojave Desert ecosystem, it is shown that new shoot production of a dominant perennial shrub is doubled by a 50% increase in atmospheric CO2 concentration in a high rainfall year, but elevated CO 2 does not enhance production in a drought year.
Abstract: Arid ecosystems, which occupy about 20% of the earth's terrestrial surface area, have been predicted to be one of the most responsive ecosystem types to elevated atmospheric CO2 and associated global climate change1,2,3. Here we show, using free-air CO2 enrichment (FACE) technology in an intact Mojave Desert ecosystem4, that new shoot production of a dominant perennial shrub is doubled by a 50% increase in atmospheric CO2 concentration in a high rainfall year. However, elevated CO2 does not enhance production in a drought year. We also found that above-ground production and seed rain of an invasive annual grass increases more at elevated CO2 than in several species of native annuals. Consequently, elevated CO2 might enhance the long-term success and dominance of exotic annual grasses in the region. This shift in species composition in favour of exotic annual grasses, driven by global change, has the potential to accelerate the fire cycle, reduce biodiversity and alter ecosystem function in the deserts of western North America.

600 citations

Journal ArticleDOI
TL;DR: In this paper, a series of subwatersheds of Waquoit Bay was studied to investigate the coupling of land to marine systems, and it was found that the increased macroalgal biomass dominates the bay ecosystem through second or third-order effects such as alterations of nutrient status of water columns and increasing frequency of anoxic events.
Abstract: Human activities on coastal watersheds provide the major sources of nutrients entering shallow coastal ecosystems. Nutrient loadings from watersheds are the most widespread factor that alters structure and function of receiving aquatic ecosystems. To investigate this coupling of land to marine systems, we are studying a series of subwatersheds of Waquoit Bay that differ in degree of urbanization and hence are exposed to widely different nutrient loading rates. The subwatersheds differ in the number of septic tanks and the relative acreage of forests. In the area of our study, groundwater is the major mechanism that transports nutrients to coastal waters. Although there is some attenuation of nutrient concentrations within the aquifer or at the sediment-water interface, in urbanized areas there are significant increases in the nutrient content of groundwater arriving at the shore’s edge. The groundwater seeps or flows through the sediment-water boundary, and sufficient groundwater-borne nutrients (nitrogen in particular) traverse the sediment-water boundary to cause significant changes in the aquatic ecosystem. These loading-dependent alterations include increased nutrients in water, greater primary production by phytoplankton, and increased macroaglal biomass and growth (mediated by a suite of physiological responses to abundance of nutrients). The increased macroalgal biomass dominates the bay ecosystem through second- or third-order effects such as alterations of nutrient status of water columns and increasing frequency of anoxic events. The increases in seaweeds have decreased the areas covered by eelgrass habitats. The change in habitat type, plus the increased frequency of anoxic events, change the composition of the benthic fauna. The data make evident the importance of bottom-up control in shallow coastal food webs. The coupling of land to sea by groundwater-borne nutrient transport is mediated by a complex series of steps; the cascade of processes make it unlikely to find a one-to-one relation between land use and conditions in the aquatic ecosystem. Study of the process and synthesis by appropriate models may provide a way to deal with the complexities of the coupling.

598 citations


Network Information
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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20242
20235,630
202210,638
20212,059
20201,701
20191,681