Human Impact of Disturbance Regime
Ecosystems do not have static states, but they often have dynamic relationships that shape their various aspects. Many forces play an important role in changing the relationship between various aspects of ecosystems. In a natural ecosystem, such as riverine habitat, natural disturbances remain an integral force that manipulates various vectors of the habitat (Noss and Cooperrider 1994). Other natural disturbances such as fires and wind also contribute to the wellbeing of ecosystem. Despite the fundamental role of natural disturbance regime in shaping the wellbeing of the ecosystem, human forces can interfere with their interactions by reducing the frequency of patterns and frequency of regimes change. Various human activities such as logging, flood control, and fire suppression affect disturbance regime, alter competition and degradation of ecosystem, and cause increase in frequency of disturbances.
In many forested areas, human activities such as logging have contributed to the change of diversity as man target specific trees leaving others to thrive. Logging is a common human practice that predisposes forest ecosystems to changes that are not similar to those caused by disturbance regimes. In most cases, human activities such as logging deplete growth of underground foliage and other forest cover, which reduce ignition capability. The decrease of forest cover in forested areas is not the only consequence, as logging also reduces the number of trees growing in a particular ecological patch. As a result, natural disturbance regimes such as wild fires are likely to decrease, and this will affect other ecological process that depends on fire. For instance, fire, a natural disturbance regime, contributes to changes in complexity of the ecosystem since some vegetation relies on it for regeneration. Human activities such as logging impede occurrence of fires and promotes growth of wetland scrubs in Gulf coastal plan (Noss and Cooperrider 1994). On the other hand, fire suppression can also have a reverse effect on ecological landscape. For instance, some forest vegetation is dependent on wild fires and fire suppression has a significant impact on them. When forest management lead to fire suppression, fuel-build can cause intense fire during fire break-ups. Consequently, intense fire will affect soils organisms, seeds, and enabling fire resistant vegetation to thrive.
Human activities such as damming have influence on flooding, an essential disturbance regime, as well as quality of water supply in forested ecosystems. Where rivers and streams have no dams, downstream ecosystem help alter the dynamics that occur due to flood-caused disturbances (Baron et al. 2003). In the United States, developments of dams in areas such as the Platte River system have contributed to alteration floods by reducing the rate of disturbances that downstream ecosystem experience (Johnson and Fryer 1996). Development of dams converts streams and rivers into artificial systems that impede downstream movement of water. Consequently, downstream areas in riparian areas will experience less flow of water due to holding of water in dams as man engage in power-generation activities (Nakumara et al. 2007). Damming of river alter routing of water, and movement of wood and other sediments. Most important, damming stabilizes hydrological regime leading to growth of vegetation on the downstream and stabilization of habit for fish and other aquatic life in riparian vegetation.
Indeed, human activities such as logging and damming of stream alter frequencies of regime disturbances. Logging can lead to removal of forest cover, while limited logging can lead to increase in fuel that can cause intense fire. Conversely, damming can reduce flooding of downstream. Logging can alter competition in forest due to selective destruction of trees. Intense fires can also harm sensitive crops and destroy soil structure and microorganism. Damming also stabilize growth of plants and consequently increase abundance of aquatic life in downstream areas.
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