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Latest Comparisons Tubercule vs. Glyptal vs. Faucet vs. Com vs. The greatest biodiversity is found in the tropical regions of the world, particularly among tropical rainforests and coral reefs. Biodiversity is increased by genetic change and evolutionary processes and reduced by habitat destruction, population decline and extinction. There is a growing recognition that the level of biodiversity is an important factor in influencing the resilience of ecosystems to disturbance.
Biodiversity is a complex term that includes not only the variety of different animals species diversity but also the difference between animals of the same species genetic diversity and between ecosystems ecosystem diversity. Genetic Diversity is the diversity of genetic characteristics expressed or recessive within a species i. This component of biodiversity is important because it allows populations to adapt to environmental changes through the survival and reproduction of individuals within a population that have particular genetic characteristics that enable them to withstand these changes.
The maintenance of high genetic diversity within populations is therefore a conservation and management priority as this provides the greatest capacity for any population to adapt to a broad range of environmental changes.
Each organism has its own niche or role in the whole system to play its part to show their importance. Biodiversity is defined as the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.
Biodiversity is a measure of the variety of life on earth. Again, Biodiversity is the variation of life forms, plants and animals within a given ecosystem, biome, or on the entire Earth.
One cannot find all the types of plants and animals all over a certain country or part of a country. Biodiversity is often used as a measure of the health of biological systems.
The biodiversity found on Earth today consists of many millions of distinct biological species that is all living beings. The diversity of ecosystems is difficult to estimate as ecosystems grade into one another and large ecosystems may contain diverse smaller ones. Our planet as a whole is an ecosystem , but it contains many others: forests, deserts and oceans for instance, which are themselves made up of smaller ecosystems , for example, coral reefs and shallow seas within the oceans.
These in turn are made up of many yet smaller ecosystems , such as mangrove swamps, which border on and grade into terrestrial ecosystems. Change in one ecosystem will impact on the others with which it overlaps and into which it grades. Species diversity refers to the number of different species in a certain area on the land, water and in burrows. Despite this, the number of species present is probably the most common measure of biodiversity used by conservationists; it is measured in different ways, but most include weighting for numbers of individuals as well as numbers of species.
Every individual is dependent on its environment, both the physical rainfall, soil type, temperature, oxygen gradient, light, etc and living other individuals of its own and other species and how these interact. Change in any aspect of these environments will impact on, and may destroy, whole communities. In addition, the richer the diversity of life, the greater the opportunity for medical discoveries, economic development, and adaptive responses to such new challenges as climate change.
The term ecosystem is defined in many ways for example as a community of living organisms combined with their associated physical environment. Ecosystems are the full tapestry of nature that support life and they also provide valuable services.
A few types of ecosystems can be mentioned as follows;. Wetland ecosystems filter out toxins, clean the water, and control floods. Then Estuaries ecosystems act as marine-life nurseries.
Forest ecosystems supply fresh water, provide oxygen, control erosion, and remove carbon from the atmosphere. Many species, working together, are needed to provide these critical services. At the ecosystem level, the total growth of all plant species is termed primary production, and — as we'll see in this article — communities composed of different numbers and combinations of plant species can have very different rates of primary production. This fundamental metric of ecosystem function has relevance for global food supply and for rates of climate change because primary production reflects the rate at which carbon dioxide a greenhouse gas is removed from the atmosphere.
There is currently great concern about the stability of both natural and human-managed ecosystems, particularly given the myriad global changes already occurring. Stability can be defined in several ways, but the most intuitive definition of a stable system is one having low variability i. This is often termed the resistance of a system. Resilience is a somewhat different aspect of stability indicating the ability of an ecosystem to return to its original state following a disturbance or other perturbation.
Species diversity has two primary components: species richness the number of species in a local community and species composition the identity of the species present in a community. While most research on the relationship between ecosystem diversity and stability has focused on species richness, it is variation in species composition that provides the mechanistic basis to explain the relationship between species richness and ecosystem functioning.
Species differ from one another in their resource use, environmental tolerances, and interactions with other species, such that species composition has a major influence on ecosystem functioning and stability. The traits that characterize the ecological function of a species are termed functional traits, and species that share similar suites of traits are often categorized together into functional groups.
When species from different functional groups occur together, they can exhibit complementary resource-use, meaning that they use different resources or use the same resources at different times.
For example, two animal predators may consume different prey items, so they are less likely to compete with one another, allowing higher total biomass of predators in the system. In the case of plants, all species may utilize the same suite of resources space, light, water, soil nutrients, etc.
Increasing species diversity can influence ecosystem functions — such as productivity — by increasing the likelihood that species will use complementary resources and can also increase the likelihood that a particularly productive or efficient species is present in the community.
While primary production is the ecosystem function most referred to in this article, other ecosystem functions, such as decomposition and nutrient turnover, are also influenced by species diversity and particular species traits. Stability can be defined at the ecosystem level — for example, a rancher might be interested in the ability of a grassland ecosystem to maintain primary production for cattle forage across several years that may vary in their average temperature and precipitation.
Figure 1 shows how having multiple species present in a plant community can stabilize ecosystem processes if species vary in their responses to environmental fluctuations such that an increased abundance of one species can compensate for the decreased abundance of another.
Biologically diverse communities are also more likely to contain species that confer resilience to that ecosystem because as a community accumulates species, there is a higher chance of any one of them having traits that enable them to adapt to a changing environment.
Such species could buffer the system against the loss of other species. In this situation, species identity — and particular species traits — are the driving force stabilizing the system rather than species richness per se see Figure 2. Figure 1: Conceptual diagram showing how increasing diversity can stabilize ecosystem functioning Each rectangle represents a plant community containing individuals of either blue or green species and the total number of individuals corresponds to the productivity of the ecosystem.
Green species increase in abundance in warm years, whereas blue species increase in abundance in cold years such that a community containing only blue or green species will fluctuate in biomass when there is interannual climate variability. In contrast, in the community containing both green and blue individuals, the decrease in one species is compensated for by an increase in the other species, thus creating stability in ecosystem productivity between years. Note also that, on average, the diverse community exhibits higher productivity than either single-species community.
This pattern could occur if blue or green species are active at slightly different times, such that competition between the two species is reduced. This difference in when species are active leads to complimentary resource utilization and can increase total productivity of the ecosystem. In contrast, if stability is defined at the species level, then more diverse assemblages can actually have lower species-level stability. This is because there is a limit to the number of individuals that can be packed into a particular community, such that as the number of species in the community goes up, the average population sizes of the species in the community goes down.
For example, in Figure 2, each of the simple communities can only contain three individuals, so as the number of species in the community goes up, the probability of having a large number of individuals of any given species goes down.
The smaller the population size of a particular species, the more likely it is to go extinct locally, due to random — stochastic — fluctuations, so at higher species richness levels there should be a greater risk of local extinctions. Thus, if stability is defined in terms of maintaining specific populations or species in a community, then increasing diversity in randomly assembled communities should confer a greater chance of destabilizing the system.
Figure 2: Conceptual model illustrating the insurance hypothesis Simple communities are represented by a box; in this case, these communities are so small that they can only contain 3 individuals.
For example, this could be the case for a small pocket of soil on a rocky hillslope. Looking at all possible combinations of communities containing 1, 2 or 3 species, we see that, as the number of species goes up, the probability of containing the blue species also goes up.
Thus, if hillslopes in this region were to experience a prolonged drought, the more diverse communities would be more likely to maintain primary productivity, because of the increased probability of having the blue species present.
A wealth of research into the relationships among diversity, stability, and ecosystem functioning has been conducted in recent years reviewed by Balvanera et al. The first experiments to measure the relationship between diversity and stability manipulated diversity in aquatic microcosms — miniature experimental ecosystems — containing four or more trophic levels, including primary producers, primary and secondary consumers, and decomposers McGrady-Steed et al.
These experiments found that species diversity conferred spatial and temporal stability on several ecosystem functions. Stability was conferred by species richness, both within and among functional groups Wardle et al. When there is more than one species with a similar ecological role in a system, they are sometimes considered "functionally redundant.
More recently, scientists have examined the importance of plant diversity for ecosystem stability in terrestrial ecosystems, especially grasslands where the dominant vegetation lies low to the ground and is easy to manipulate experimentally. In , David Tilman and colleagues established experimental plots in the Cedar Creek Ecosystem Science Reserve, each 9 x 9 m in size Figure 3A , and seeded them with 1, 2, 4, 8 or 16 species drawn randomly from a pool of 18 possible perennial plant species Tilman et al.
Plots were weeded to prevent new species invasion and ecosystem stability was measured as the stability of primary production over time.
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