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Accelerating rates of biodiversity loss have led ecologists to ..

01/03/2014 · The importance of biodiversity to human health: An ecological Perspective

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Tree biodiversity critical to forest productivity, study finds

ONE of the ecological tenets justifying conservation of biodiversity is that diversity begets stability. Impacts of biodiversity on population dynamics and ecosystem functioning have long been debated, however, with many theoretical explorations but few field studies. Here we describe a long-term study of grasslands which shows that primary productivity in more diverse plant communities is more resistant to, and recovers more fully from a major drought. The curvilinear relationship we observe suggests that each additional species lost from our grasslands had a progressively greater impact on drought resistance. Our results support the diversity-stability hypothesis, but not the alternative hypothesis that most species are functionally redundant. This study implies that the preservation of biodiversity is essential for the maintenance of stable productivity in ecosystems.

Tree biodiversity critical to forest productivity, ..

Accelerating rates of biodiversity loss have led ecologists to explore the effects of species richness on ecosystem functioning and the flow of ecosystem services. One explanation of the relationship between biodiversity and ecosystem functioning lies in the spatial insurance hypothesis, which centers on the idea that productivity and stability increase with biodiversity in a temporally varying, spatially heterogeneous environment. However, there has been little work on the impact of dispersal where environmental risk are more or less spatially correlated, or where dispersal rates are variable. In this paper, we extend the original Loreau model to consider stochastic temporal variation in resource availability, which we refer to as "environmental risk", and heterogeneity in species dispersal rates. We find that asynchronies across communities and species provide community-level stabilizing effects on productivity, despite varying levels of species richness. Although intermediate dispersal rates play a role in mitigating risk, they are less effective in insuring productivity against global (metacommunity-level) than local (individual community-level) risks. These results are particularly interesting given the emergence of global sources of risk such as climate change or the closer integration of world markets. Our results offer deeper insights into the Loreau model and new perspectives on the effectiveness of spatial insurance in the face of environmental risks.

Global biodiversity patterns: from description ..

Global biodiversity patterns: from description to ..

Accelerating rates of biodiversity loss have led ecologists to explore the effects of species richness on ecosystem functioning and the flow of ecosystem services. One explanation of the relationship between biodiversity and ecosystem functioning lies in the spatial insurance hypothesis, which centers on the idea that productivity and stability increase with biodiversity in a temporally varying, spatially heterogeneous environment. However, there has been little work on the impact of dispersal where environmental risk are more or less spatially correlated, or where dispersal rates are variable. In this paper, we extend the original Loreau model to consider stochastic temporal variation in resource availability, which we refer to as "environmental risk", and heterogeneity in species dispersal rates. We find that asynchronies across communities and species provide community-level stabilizing effects on productivity, despite varying levels of species richness. Although intermediate dispersal rates play a role in mitigating risk, they are less effective in insuring productivity against global (metacommunity-level) than local (individual community-level) risks. These results are particularly interesting given the emergence of global sources of risk such as climate change or the closer integration of world markets. Our results offer deeper insights into the Loreau model and new perspectives on the effectiveness of spatial insurance in the face of environmental risks.

In particular, we focus on whether biodiversity affects plant productivity. Productivity is the amount of plant biomass produced on a given area of land, over a given amount of time. If a grassland were being used to produce hay, its annual productivity would be the amount of hay that it could produce each year. We use aboveground plant biomass as a measure of annual productivity. In our system productivity approximates biomass because no aboveground plant biomass from the previous year survives to the current year. Each year, aboveground plant biomass either dies and decomposes or is consumed in the spring fires we set. Productivity is an important ecosystem trait, as all higher trophic levels depend upon it directly or indirectly as a food resource. In addition, maximizing productivity is a goal of many pasture, forestry, and agricultural systems, and it is possible that insights about the effects of biodiversity can be applied to some of these systems.

Ecological effects of biodiversity - Wikipedia

Title: Biodiversity and Ecosystem Productivity in a Fluctuating Environment: The Insurance Hypothesis: Authors: Yachi, Shigeo; Loreau, Michel: Affiliation:

AB - ONE of the ecological tenets justifying conservation of biodiversity is that diversity begets stability. Impacts of biodiversity on population dynamics and ecosystem functioning have long been debated, however, with many theoretical explorations but few field studies. Here we describe a long-term study of grasslands which shows that primary productivity in more diverse plant communities is more resistant to, and recovers more fully from a major drought. The curvilinear relationship we observe suggests that each additional species lost from our grasslands had a progressively greater impact on drought resistance. Our results support the diversity-stability hypothesis, but not the alternative hypothesis that most species are functionally redundant. This study implies that the preservation of biodiversity is essential for the maintenance of stable productivity in ecosystems.

N2 - ONE of the ecological tenets justifying conservation of biodiversity is that diversity begets stability. Impacts of biodiversity on population dynamics and ecosystem functioning have long been debated, however, with many theoretical explorations but few field studies. Here we describe a long-term study of grasslands which shows that primary productivity in more diverse plant communities is more resistant to, and recovers more fully from a major drought. The curvilinear relationship we observe suggests that each additional species lost from our grasslands had a progressively greater impact on drought resistance. Our results support the diversity-stability hypothesis, but not the alternative hypothesis that most species are functionally redundant. This study implies that the preservation of biodiversity is essential for the maintenance of stable productivity in ecosystems.

01/03/2014 · The importance of biodiversity to human health: An ecological Perspective . Cleber J. R. Alho. Cleber J. R. Alho has a …
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Fire is an important disturbance in African savannas where it is generally assumed that high levels of pyrodiversity (variation in aspects of the fire regime) are necessary to maintain high levels of biodiversity.

Forests | An Open Access Forestry Journal from MDPI

This experiment was set up to examine the effects of manipulating species richness on plant productivity and biomass. Human impacts are driving many species locally and globally extinct. These human impacts include habitat loss or fragmentation, habitat modifications such as pollution and introductions of exotic species, and climate change. Fragmentation or fast shifts in climate may limit the number of species that occur in a habitat simply because the seed of that species cannot reach that area. Our experiment is analogous to this situation in that we allow the seed of many species to reach some areas, and restrict the number of species able to reach other areas. We do not focus on the loss of a particular species, but rather ask whether the loss of biodiversity has any general, predictable effects.

Forests, an international, peer-reviewed Open Access journal.

AB - The functioning and sustainability of ecosystems may depend on their biological diversity. Elton's hypothesis that more diverse ecosystems are more stable has received much attention, but Darwin's proposal that more diverse plant communities are more productive, and the related conjectures that they have lower nutrient losses and more sustainable soils, are less well studied. Here we use a well-replicated field experiment, in which species diversity was directly controlled, to show that ecosystem productivity in 147 grassland plots increased significantly with plant biodiversity. Moreover, the main limiting nutrient, soil mineral nitrogen, was utilized more completely when there was a greater diversity of species, leading to lower leaching loss of nitrogen from these ecosystems. Similarly, in nearby native grassland, plant productivity and soil nitrogen utilization increased with increasing plant species richness. This supports the diversity-productivity and diversity-sustainability hypotheses. Our results demonstrate that the loss of species threatens ecosystem functioning and sustainability.

Biodiversity and the productivity of ecosystems

N2 - The functioning and sustainability of ecosystems may depend on their biological diversity. Elton's hypothesis that more diverse ecosystems are more stable has received much attention, but Darwin's proposal that more diverse plant communities are more productive, and the related conjectures that they have lower nutrient losses and more sustainable soils, are less well studied. Here we use a well-replicated field experiment, in which species diversity was directly controlled, to show that ecosystem productivity in 147 grassland plots increased significantly with plant biodiversity. Moreover, the main limiting nutrient, soil mineral nitrogen, was utilized more completely when there was a greater diversity of species, leading to lower leaching loss of nitrogen from these ecosystems. Similarly, in nearby native grassland, plant productivity and soil nitrogen utilization increased with increasing plant species richness. This supports the diversity-productivity and diversity-sustainability hypotheses. Our results demonstrate that the loss of species threatens ecosystem functioning and sustainability.

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