The Impact of Woodland Management Practices on Biodiversity - Essay Example

? The Impact of Woodland Management Practices on Biodiversity Word Count: Introduction Population declines and local or widespread extinctions are common side effects of human habitation. Biodiversity is changing throughout the global at a rapidly growing rate, influenced by changes not only in local environments, but in global environments that have occurred due to human activities (Sala et al., 2000). This is true throughout the world, in many different types of environments (Myers et al., 2000), but one where biodiversity is becoming an increasingly severe problem is in woodland management. Woodlands are important areas both from the perspective of biodiversity and human use. For humans, woodlands provide a valuable resource in terms of the wood from cutting down trees, and in some cases the use of cleared land for farmland. Both of these uses of woodland significant disrupt the species living within it, often displacing them or causing local extinction. The purpose of this essay is to examining practices of woodland management and to consider what impact these have on biodiversity and what the long-term outcomes of these approaches are likely to be. In addition, alternative approaches to current woodland management practices will be considered, as well as the underlying drivers that influence what woodland management practices are prevalent. It is argued that current woodland management practices place the biodiversity within the woodland environment at significant risk, and in the long-term will result in an unrecoverable loss of species, ultimately decreasing the usefulness of woodland as a resource. Importance of Biodiversity Biodiversity has become a buzzword of the modern political environment, and is a prominent topic among many different people and areas, including universities, politicians, schools and broadcasters. The current age is often referred to as having a biodiversity crisis, or that there are many threats to biodiversity which must be properly handled in order to conserve biodiversity. The term has become highly popular and politically centred in recent years, and humankind attempts to find ways of preserving biodiversity without compromising growth and human life. However, biodiversity itself is difficult to define, as the term is used by a wide range of people, many of whom do not define what they mean by the phrase. Throughout literature there are more than 80 different definitions of the term, which vary slightly or significantly from one another (Spicer, 2009). The definition of biodiversity that is arguably the most correct is that which was derived as part of the Convention on Biological Diversity, which was signed by 150 nations in 1992. This definition considers biodiversity to be variability among living organisms from all areas of the world, including diversity that occurs within ecosystems, between species and within species. Defining the term however, is only one aspect. To effectively address the problems surrounding biodiversity, there needs to be an effective method of measuring it. Finding consensus approaches to measuring biodiversity is an important approach to solving problems of biodiversity; however, this is not an easy task. For example, a forest ecosystem has a large amount of different species including the easily visible plants, animals and birds, the smaller organisms such as insects, and then microorganisms, which cannot be seen with the naked eye. Counting all of these species would be a large task, and does not take into account another important aspect of biodiversity, specifically , how many of each species are present (Spicer, 2009). Because of these problems, different researchers make use of different approaches to attempt to provide an indication of the measure of biodiversity within an area, such as the number of species that are present or their abundance. Often, a specific type of species may be focused on, such as studies that examine the biodiversity of birds within forest communities (Aleixo, 1999). Other indicators of biodiversity that are used for woodland include how natural the tree species composition is, the diversity of tree species and the level of standing dead wood (Seidl et al., 2007) There are many important aspects to biodiversity. The first is that if a species becomes extinct, it cannot be retrieved; there is no method that can be used to reintroduce an extinct animal or plant onto the planet. Furthermore, species that are close to extinction have limited genetic variation, which cam make population recovery and survival difficult. This suggests that biodiversity cannot be ignored because all or some of the species concerned are currently high in numbers. A second aspect is that all species within an ecosystem play an important role, many of which we are unaware of. The loss of a species often decreases the productivity and stability of an ecosystem, making further losses likely in the future (Folke et al., 2004). Woodland Practices The structure of vegetation is believed to be one of the key aspects determining the species richness and biodiversity at a local level. Any form of human interaction within the woodland environment has the potential to interfere with the natural processes occurring within the forest, and impact biodiversity (Aleixo, 1999). While biodiversity across all types of ecosystems has become an important aspect of modern legislation and consideration, biodiversity within woodland ecosystems is a highly politically charged aspect, some of which are considered to be the last “pristine places” in the world. In Europe, the woodland cover has been dramatically decreased, with estimates suggesting that at the beginning of the 20th century, forestation covered only five percent of the land. Since this point, the level of forestation has risen to around 12%, due to programs specifically focused at reintroducing forested environment (Fuentes-Montemayor et al., 2012). Woodland management practices is strongly influenced by the desires of many different people, including politicians, environmentalists and businesses, all of which have strong, and often contradictory, points of view. Woodlands have been subject to high levels of human use for a long time, and it is likely that this trend will continue into the future (Piussi and Farrell, 2000). The debate about forests comes from the fact that they hold a large number of resources that are important for economic growth while also being critical places for biodiversity. Tropical rainforests are one of the most widely cited examples of this because they are estimated to contain at least half of all the biodiversity within the world, yet are responsible for less than ten percent of the earth’s surface coverage. However, forests are also the source for products such as chocolate, coffee, quinine, bananas, wood and pharmaceuticals, creating a constant conflict between the value of forest itself, and the value of its products (Vandermeer and Perfecto, 2005). Woodlands can be subject to a range of different types of woodland management practices based on many factors, such as whether the region has conservation status, if it is being actively logged, what the objectives of the landowner and/or government is, and what pressures the land is under, such as from pest species. The type of management can have an impact on the richness and abundance of species within an area. One study identified some woodland management practices as coppicing and ride management as well as non-managed woodland (Merckx et al., 2012). In this study, the author was looking at woodland management practices for areas where the landscape was under intensive human use. Coppicing and Ride Widening Both ride widening and coppicing are forms of woodland management that are effective in dense forests that serve to change the structure of the area, opening it up and providing easier access for humans. This form of management also impacts the species that life in the area, as it changes the structure, and influences the environment, such as the level of light present and whether the species is directly next to other trees or not. This has the potential to alter competition between species, favouring species that were at a disadvantage previously (Merckx et al., 2012). Coppice management was often used in Europe, although current practices have shifted away from this approach. Although coppice management has the potential to reduce biodiversity, it also decreased the susceptibility of the forests to fire (Piussi and Farrell, 2000). Logging In many cases, logging removes native trees and forested environments, creating plantations as a way of ensuring resources for the future, and of removing any negative effect that they had on the environment and biodiversity. However, forestry plantations are significantly different than native woodland, and consist of many similar species, with exotic fast-growing tree species being common. Because of this, there is low biodiversity within these regions, and many of species that are present in natural forested environments are not in the plantations (Fuentes-Montemayor et al., 2012). One woodland management practice that is used in some parts of the world is selective logging. This approach is an attempt to find a middle ground between the economic needs of people, and biodiversity within the forest. While regular approaches to logging remove a large number of trees close together, resulting in patches of land, selective logging is an approach that attempts to be more sustainable. Instead of removing all trees present within a stand, selective logging removes trees that have been marked, while others are left standing. It is argued that this approach is better for the environment and minimises the impact that logging has on biodiversity (Robinson and Robinson, 1999). However, selective logging does still have some impacts on the biodiversity of species. This is because although large patches of bare land are not created, the logging practice still leaves gaps within the vegetation. These gaps can have significant effects on vegetation growth within the area and different species are favoured within the gap than in the forest normally. This growth is believed to be one of the key factors in the biodiversity of birds within a forest, and potentially also other types of species (Aleixo, 1999). One study examined the impacts of selective logging on bird species within a forest in the Brazilian Atlantic. Although only two forests were examined, the author found that although the species composition between the two sites was similar, some species were present in one area and not in another (Aleixo, 1999). Another, more rigorous study examined what impact selective logging had on a forest within southern Illinois in the United States. In their study, the authors compared the abundance of a range of different bird species in areas where no cutting had occurred, there had been recent cutting or historical cutting. They found that for most species of bird, there was no significant difference in abundance between cut and uncut areas, however, the abundance of two species was decreased in cut areas, and one species was increased. In the long-term, these changes in abundance could potentially affect the structure of the ecosystem within the region, and also influence biodiversity. For example, the bird species that was increased in cut areas was the Blue Jay, a nest predator. This species can decrease the abundance of other species, potentially driving them from the area and making them locally extinct (Robinson and Robinson, 1999). Fragmentation Fragmentation can occur as the result of many different forest management strategies and is where there is no longer a single stretch of forest, but multiple smaller pockets of forest, surrounded by unforested land. Some ways that fragmentation can occur is through the conversion of forest to agriculture, logging or road construction (Zuidema et al., 2005). Fragmentation is an area of ecology that has been highly studied through a range of different approaches and definitions (Fahrig, 2003). It is a difficult phenomenon to study, because it generally involves comparing fragmented and non-fragmented forests, which may differ in other respects also (McGarigal and Cushman, 2002). Fragmentation has a number of different effects on the forest environment and the species within it, many of which have significant impacts on biodiversity (Olff and Ritchie, 2002). For example, fragments in forest patches make it difficult for animals to roam far, which is problematic for those that need large ranges or are territorial. It also produces effects where the plants and animals that are closest to the edge of the new fragment are suddenly subject to a wide range of new forces, such as a higher level of light and wind. For some species this may mean that they are no longer the most highly competitive plant and may be outcompeted by another species. For many species, particularly plant species, the gaps between forest may serve as a significant barrier to dispersal, creating higher competition within the forest as a consequence (Kupfer et al., 2006). An additional problem is that in small fragments, most areas of the fragment are close to the edge, resulting in significantly different internal processes than within a forest (Hanski, 2005). Species-Specific Management In some cases, woodland management practices may be more productive at maintaining biodiversity if they focus on the removal or exclusion or particular pest species. There are many examples where specific animals can have a strongly negative effect on biodiversity within a particular system. For example, in many native woodlands, deer selectively browse on vulnerable herms, young trees and shrubs, resulting in significant changes in vegetation and sometimes local extinction of some species (Gill, 2000, Cote et al., 2004). In New Zealand, deer browsing resulted in destruction of native species, but when the browsing was prevented, recruitment of the species occurred. Over a ten year period, restriction of browsing lead to the replacement of some of the tree species, whose saplings the deer had been eating (Coomes et al., 2003, Husheer et al., 2003). Woodland management practices in many countries are based off this concept of minimising the presence of specific species that have the potential to significantly harm the ecosystem(Brockerhoof et al., 2001). Differences between Forests Woodlands are complex ecosystems that contain a large number of species and are subject to different social and environment effects depending on the forest’s location in the world. Because of this, the impacts of management processes differ substantially from one forest to another, particularly across different forest types (Piussi and Farrell, 2000). For example, it is possible that a normally safe form of management has a particularly negative effect on a native species in a particular forest, leading to cascading effects throughout the system. As such, it is important to consider the effects of different forms of management independently for each forest, using information from regionally close and structurally similar forests as a guide. Policy makers and forest scientists are beginning to consider that indigenous and local knowledge about forests and how they have traditionally been used has the potential to significantly influence the way that forests are managed. This knowledge is important the ability to provide a more relevant assessment of what forms of management are likely to be effective at maintaining biodiversity and which are not. Another different to take into account between forests in terms of biodiversity is past-land use. Not all forested lands have always been forested, many have been deforested at some point during human history and have since become reforested. If deforestation has occurred in the past, particularly if the land was used for agriculture, the level of biodiversity that the land can support is likely to be significantly different than land which has not been deforested (Dupouey et al., 2002). This is important for management practices to take into account, as without considering this, a higher level of biodiversity than possible may be expected. Future Perspectives Effectively maintaining biodiversity within forests has become a critical factor for ensuring the continuation of our environment for later generations, and also for the presence of woodland communities that can continue to provide resources. To achieve this, woodland management practices need to pay special attention to the issues of biodiversity, and be aware that many practices that may seem benign can potentially harm or destroy species that live within that habitat. Understanding the most effective management tools is an important approach to finding a balance between human need and biodiversity. Ecological knowledge plays an important role in this (Piussi and Farrell, 2000). It is important to be aware that the impacts of woodland management on biodiversity are unlikely to be static. Forests are believed to be particularly vulnerable to changes in the climate through global warming, in part because they lack the ability to move to an environment that is more suitable if the climate changes substantially. Increases in temperature as the result of global warming have the potential to influence interactions within the woodland environment and may affect biodiversity (Linder et al., 2010). It is important that woodland management practices take into account these potential future changes and be aware of how they may affect management practices. Conclusion Within forests, the type of woodland management practices that are achieved have the potential to significantly influence the level of biodiversity that is present. While biodiversity varies significantly across different forest types, locations, and histories, human impact has the potential to substantially decrease the level of biodiversity in many woodland environments. It is a matter of carefully considering the management options available for a given woodland environment, and determining which is likely to cause the least loss of biodiversity. This may involve using forms of management practice that are low in impact, such as selective logging or excluding pest species, which leave the majority of the forest habitat mostly unaffected. As the studies showed, all forms of forest use have some level of impact on biodiversity, and as such, the aim of management should be to minimise this, rather than prevent it from happening. References Aleixo, A. 1999. Effects of selective logging on a bird community in the Brazilian Atlantic Forest. Condor, 537-548. Brockerhoof, E. G., Ecroyd, C. E. & Langer, E. R. 2001. Biodiversity in New Zealand plantation forests: Policy trends, incentives, and the state of our knowledge NZ Journal of Forestry, May, 31-37. Coomes, D. A., Allen, R. B., Forsyth, D. M. & Lee, W. G. 2003. 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