Animal Disturbances in Eastern Deciduous Forests

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The study of ecology is currently primarily focused upon anthropogenic effects on ecosystems as well as feeding relationships; however, non-feeding interactions are also an important factor in understanding the balance of the ecosystem and identifying issues. These interactions are generally termed disturbances. What constitutes a disturbance? White and Pickett defined it as “any relatively discrete event in time that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment” (White 1985). Some definitions of disturbances such as Grime's require the destruction of biomass, however, this tends to rule out many events that cause changes in the makeup of ecosystems yet are not feeding interactions (Buckley 1992). All animals interact with their environment beyond simply feeding as even walking can affect the makeup of the environment by crushing grasses or insects. Still, not all animals have the same degree of effect on the environment - certain animals are considered to be “ecosystem engineers.” These ecosystem engineers include crocodiles and beavers, animals that substantially change the environment around them to adapt it to their needs. Clive G. Jones defined ecosystem engineers as “organisms that directly or indirectly modulate the availability of resources to other species, by causing physical state changes in biotic or abiotic materials. In doing so, they modify, maintain, and create habitats”(Jones 1994). Of course, not all organisms that have non-trophic effects on their environment are ecosystem engineers. It is simply that the effects of the ecosystem engineer tend to be the best studied as they have the largest, most deliberate effect. H... ... middle of paper ... ...ing monoculture comes a plethora of plant viruses that were previously reduced by diversity. As Castello states: “As forests become monocultures of one or several species, and as they suffer from mismanagement...they become more vulnerable to the impacts of biotic and abiotic stresses”(Castello 1989). Problematically, little is known about plant viruses and thus little is known about how to manage forests to prevent viruses or reduce their impact. There is some disagreement on whether a lack of disturbances truly leads to monoculture as certain ecologists including Hubbell believe that recruitment failures outweigh any possible effect of disturbances (Hubbell 1999). However, as studies have shown, disturbances can drastically increase recruitment failures. Nearly all researchers did agree that anthropogenic disturbances universally reduce diversity in ecosystems.

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