Ecological impacts of biodiversity loss

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Abstract

Human changes of the global ecology have caused major loss of biodiversity, leading to general changes in the international distribution of organisms. The ecological impact of biodiversity loss appears inexorable, with impacts felt all over the world. These alterations in biodiversity have altered ecosystem processes and altered the resistance of ecosystems to ecological change. The ecological impacts of biodiversity loss include carbon storage, nutrient cycling, hydrology, productivity, water cycles, and climate and weather patterns. This has great effect on the goods and services that the ecosystem provides to humans.

Introduction

Human actions are continuing to impact the environment both on local and international levels. Most of these actions are resulting in dramatic alterations in the biotic composition of the biological communities, in terms of loss of species. This has greatly affected the way the ecosystems work. Changed biodiversity has resulted in great concerns for several markets as well as non-market reasons, compelling ecologists to want to find out the impacts of altering biodiversity on ecosystem features including carbon storage, nutrient cycling, hydrology, productivity, water cycles, climate and weather patterns (Goudie, 2006). This paper will examine the effects of such basically anthropogenic alterations in biodiversity in terms of the goods or services that the ecosystem offers to beings. It will explore whether the changes in the ecosystem properties caused by the altered biodiversity does negatively affect the human welfare.

Humans have greatly changed the global environment, altering global biogeochemical cycles, changing land and increasing the movement of biota. Human activities have led to the elimination of many species on earth. Although extinction is a natural process, it is taking place at an unnaturally high rate due to human actions.  Currently, humans have caused the loss of 5-20% species of plants and animals (Hector, et al. 1999). In fact, the present rates of loss are projected to be almost 1,000 times higher compared to pre-human rates. Local species extinctions can greatly affect the ecosystem properties. Soil processes in specific appear to be the most affected by the loss of biodiversity.  For instance, nutrient intake by soil micro-organisms, soil organic, nutrient retention and decomposition are the most soil processes affected by the loss of biodiversity. The rate of nutrient cycling and decomposition are affected by the presence of a variety of organisms in the soil (Hooper, & Vitousek, 1997).

Plant community structure and productivity are influenced by the structure and variety of mycorrhizal fungi in the soil. The soil faunal community’s composition also influences the rate of litter decomposition. Studies indicate that there exist a significant linear and asymptotic association between ecosystem functionality and species richness. Nutrient retention and productivity increases with an increase in plant species richness.  Arbuscular mycorrhizal species abundance appears to improve plant yield in an asymptotic manner while the presence of 14 species of fungi tends to increase the uptake of phosphorus in a linear manner. Microbial abundance may contribute to the enhanced decay of organic matter (Sala, et al. 2000).

Higher plant diversity affects productivity and improves the stability of biota processes.  Research studies have demonstrated that regions with higher diversity experience higher productivity.  Soils with a greater diversity of species retained nutrients better compared to soils with fewer species. Research findings show that 50% decrease in biodiversity result to 10%-20% decrease in productivity (Hooper, & Vitousek, 1997). A Highly diverse field yields twice the amount of produce from a monocrop field. Plots with low diversity experience greater loss of nutrients, leading to the decreased production. Decreased productivity means less food is available to adequately cater for the needs of a growing population and this would ultimately result in poorer health. Moreover, biodiversity is virtually a vast source of natural cures and remedies. Biodiversity provides humans with a vast range of medicinal herbs and plants. Thus, loss of biodiversity will lead to the reduction in the diversity of natural remedies that humans use, resulting in poorer health. The loss of certain plant species has led to decreased evapotranspiration and rainfall. For example, the removal of tropical forest and their replacement with savannah grasses have caused a significant reduction in evapotranspiration and in turn reduced rainfall. This has considerably eliminated the likelihood of forest regeneration and the survival of the remaining trees. Thus, the loss of species is resulting into the impoverishment of the ecosystem (Hector, et al. 1999).

Loss of diversity affects species interactions, which are the most vital properties of the ecosystem. Species interact with other organisms within the ecosystem, creating highly complex intertwining systems. They collaborate, compete, prey, parasitize and provide shelter or food to one another. Moreover, in these interactions, they alter the non-biological properties of the ecosystem, such as energy sources, nitrogen, water, and nutrients. There are three types of species interactions: competition; mutualism and trophic interactions. Mycorrhizal relationships between fungi and plants roots are an example of mutualistic species interactions that greatly help to plant to absorb nutrients from the soil. Trophic interactions directly influence the ecosystem through altering fluxes of material and energy as well as through influencing the richness of species which control those fluxes (Walker, et al., 1999).

Figure 1: Trophic interactions may influence ecosystem through influencing species abundances

Trophic interactions may influence ecosystem through influencing species abundances

  • A. Russian fur traders got rid of sea otters, causing an increase in the growth of sea urchins which overgrazed kelp.
  • B. Alteration in the species abundance and balance of fish may cause algal blooms and deplete phytoplankton grazers.

Biodiversity serves as a stabilizing element in ecosystems. Highly diverse ecosystems may serve to decrease the effect of modifications in the ecosystem.  The diversity of plant and animal in the rainforest helps maintain complex ecosystems and their health. Rainforests are extremely crucial global climate regulators since they are the largest storages of biodiversity on earth. They serve as pollution filters through absorbing CO2 from the atmosphere, which is the greatest air pollutant that causes climate warming, destabilizing climate patterns all over the world. Rainforests help stabilize global climate and make it function properly through removing CO2 from the atmosphere. The loss of biodiversity makes rainforests to get weaker, degenerate and lose their ability to absorb CO2, worsening the already worse ecological issue of global warming and causing other climate change issues (Naeem, & Li, 1997).

Agriculture requires a variety of conditions for maximum productivity. Natural ecological elements and processes are responsible for the creation of these conditions. Biodiversity, in specific vegetation, is crucial when it comes to regulation of water for cultivation. They are vital in providing a reliable supply of water to crop fields, such as by retaining water in wetlands. Currently, forested catchment provides us with 75% of freshwater supplies and hence water is crucially linked to forests (Naeem, & Li, 1997). Moreover, these ecosystem processes help mitigate global warming. Genetic diversity helps in increasing and maintaining productivity levels and nutritious diversity. Biodiversity can generate pest suppressive conditions as well as greater resilient to the invasion of agricultural systems by harmful species. Pollinators are critical to the production of various crops and lead to enhancements in the quality of fiber crops and fruits. Biodiversity provides an abundance and variety of pollinators (Walker, et al., 1999).

Biodiversity reinforce pest control, which is another major ecosystem service. The richness of natural pests’ enemies greatly determines this service of pest control. The diversity of natural pests’ enemies leads to enhanced pest control. Non-crop habitats are essential for the existence and survival of pest control agents, such as predators and parasitoids. Landscape diversity and juxtaposition to semi-natural habitats appear to generate a greater richness and species diversity of natural enemies. Therefore, biodiversity loss appears to be the major threat to providing pest control as an ecosystem service (Sala, et al. 2000).

Conclusion

Loss of biodiversity seems to impact the ecosystems in the same measure as pollution, global warming and other major types of environmental stress. Human actions on biodiversity have the potential to adversely affect the functioning of the ecosystems. Biodiversity determines the properties of the ecosystem and in turn influences the goods and services that the ecosystem can provide to humans. Species richness, composition, and interactions tend to influence the properties of the ecosystem. Ecological research studies demonstrate that ecosystem properties are influenced by biodiversity when it comes to the functional properties of the existing organism and their distribution and richness over time and space. Thus, this paper has clearly demonstrated that there exist a significant correlation between the loss of biodiversity and ecosystem functioning.

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  1. Goudie, A. 2006: The Human Impact on the Natural Environment. The MIT Press. Sixth Edition
  2. Hector, A. et al. 1999. Plant diversity and productivity experiments in European grasslands. Science 286, 1123–1127.
  3. Hooper, D. U. & Vitousek, P. M. 1997. The effects of plant composition and diversity on ecosystem processes. Science 277, 1302–1305.
  4. Naeem, S. & Li, S. 1997. Biodiversity enhances ecosystem reliability. Nature 390, 507–509
  5. Sala, O. E. et al. 2000. Global biodiversity scenarios for the year 2100. Science 287, 1770–1776
  6. Walker, B., Kinzig, A. & Langridge, J. 1999. Plant attribute diversity, resilience, and ecosystem function: the nature and significance of dominant and minor species. Ecosystems 2, 95–113.
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