Passage I: Consequences of biodiversity loss (Part III)
c. Species interactions: Species interactions are perhaps the most important aspect of ecosystem functioning. Species are not just “there,” they are interacting at some level with all the other organisms in the system, forming highly complex interlocking systems. They compete, they parasitize, they cooperate, they prey, they provide food or shelter. In these interactions they also modify the nonbiological aspects of the ecosystem: the availability of nutrients, energy sources (such as sunlight), water, nitrogen (nitrogen-fixing organisms) and the like.
i) Mutualistic interactions: These interactions are essential in ecosystems. One example is the mycorrhizal associations between fungi and the roots of plants, or the decomposition of organic material in the soil by microorganisms, each species of which may contribute different enzymes to the decay process. The organic compounds thus released are taken up by forest plants, which provide the organic matter for the next cycle.
ii) Trophic interactions: Ecosystem functions depend greatly upon trophic interactions among species within that system. For instance, if carnivores are removed, prey species populations may grow tremendously, leading to a series of changes in the system.
d. Ecosystem stability: the ”diversity-stability hypothesis”: The idea behind this hypothesis is that biodiversity acts as a stabilizing factor in ecosystems, and that therefore highly diverse ecosystems can act to reduce the impact of changes in the environment. Since humans are now altering so many environmental variables – atmospheric gases, surface temperatures, water quality – it behooves us to maintain as many areas with high biodiversity as possible. The more species, the more likely that at least some will remain after environmental changes occur. Some species may also be capable of mitigating the effects of the changes.
Passage I: Consequences of biodiversity loss (Part III)c. Species interactions: Species interactions are perhaps the most important aspect of ecosystem functioning. Species are not just “there,” they are interacting at some level with all the other organisms in the system, forming highly complex interlocking systems. They compete, they parasitize, they cooperate, they prey, they provide food or shelter. In these interactions they also modify the nonbiological aspects of the ecosystem: the availability of nutrients, energy sources (such as sunlight), water, nitrogen (nitrogen-fixing organisms) and the like.i) Mutualistic interactions: These interactions are essential in ecosystems. One example is the mycorrhizal associations between fungi and the roots of plants, or the decomposition of organic material in the soil by microorganisms, each species of which may contribute different enzymes to the decay process. The organic compounds thus released are taken up by forest plants, which provide the organic matter for the next cycle.ii) Trophic interactions: Ecosystem functions depend greatly upon trophic interactions among species within that system. For instance, if carnivores are removed, prey species populations may grow tremendously, leading to a series of changes in the system.d. Ecosystem stability: the ”diversity-stability hypothesis”: The idea behind this hypothesis is that biodiversity acts as a stabilizing factor in ecosystems, and that therefore highly diverse ecosystems can act to reduce the impact of changes in the environment. Since humans are now altering so many environmental variables – atmospheric gases, surface temperatures, water quality – it behooves us to maintain as many areas with high biodiversity as possible. The more species, the more likely that at least some will remain after environmental changes occur. Some species may also be capable of mitigating the effects of the changes.
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