Habitat Destruction

10 Key excerpts on "Habitat Destruction"

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  eBook - ePub

  Animals and Human Society

  • Colin G. Scanes, Samia Toukhsati(Authors)
  • 2017(Publication Date)
  • Academic Press

    (Publisher)

  Chapter 19

  Human Activity and Habitat Loss: Destruction, Fragmentation, and Degradation

  Colin G. Scanes    University of Wisconsin–Milwaukee, Milwaukee, WI, United States

  Summary

  Humans have a detrimental impact on natural habitat due to various activities including deforestation, urbanization, roads, the energy sector (renewable and coal), mining, and climate change. The most important form of Habitat Destruction is deforestation either to develop land for agriculture (70%) or to harvest lumber intensively. There is ongoing economic pressure to convert the forests of the Amazon to pasture and arable land, for example, for corn and soybean production for the growing pig and poultry sectors. In Malaysia, Indonesia, and sub-Saharan Africa, there is growing production of palm oil with native forests being converted to oil palm plantations. The number and proportion of people living in urban areas is increasing rapidly with 5.8 million ha urbanized between 1970 and 2000 globally. Roads are influencing habitats particularly with the destruction of wetlands and habitat fragmentation. It is estimated that by 2050, there will be an additional 15.5 million miles (25 million km) of roads. The energy sector (e.g., coal mining and wind turbines) is also responsible for habitat loss. Environmental contamination associated with the extractive industries poses risks to wildlife and is viewed as potential habitat degradation. Even the vaulted wind turbines degrade habitat with substantial fatalities for birds (>200,000 in the USA) and bats (>800,000 in the USA). Mining also degrades and/or destroys habitats; for instance, unregulated gold mining can cause considerable damage including release of toxicants including cyanide, arsenic, boron, copper, fluoride, mercury, and zinc. Anthropomorphic (human-induced) climate change is degrading habitats, such as the polar region and the oceans due to acidification.

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  Conservation Biology

  • Andrew S. Pullin(Author)
  • 2002(Publication Date)
  • Cambridge University Press

    (Publisher)

  By reading this chapter students will gain an understanding of the effects of Habitat Destruction and fragmentation on communities of species, on populations, and on genetic diversity within populations. They will gain understanding of how fragmentation of habitat decreases the species diversity and increases the probability of species extinction at the site and landscape scales. Introduction There is an intimate and complex relationship between a species and its habitat and the former has certain requirements for persistence: either abiotic (e.g. microclimate) or biotic (e.g. food or symbionts) that their habitat provides. In some species, habitat requirements are much more specific than others (some are specialists and some generalists), but there are usually definable elements that are vital, even for generalists, especially for successful reproduction. If a species has been sufficiently well studied, its presence or absence can often be predicted on the basis of presence or absence of key habitat features, and it follows that if these key features are removed the species will disappear also. Deterministic versus stochastic effects of habitat loss The scale of destruction described in the previous chapter means that the habitats of some species have been lost completely. In the absence of human intervention (in the form of ex situ conservation, see Chapter 11), no species can survive when the habitat to which it is adapted is sud-denly and totally removed. This is a foreseeable or predictable effect of total Habitat Destruction and we can therefore describe it as determin -istic extinction . No habitat – no species. In fact, cases of extinction are rarely as simple as this and fortunately there are few cases of total Habitat Destruction that have been recorded. Usually, one or two fragments remain in which the species may persist for some time (see below).

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  Self-Organization in Complex Ecosystems

  • Ricard Solé, Jordi Bascompte(Authors)
  • 2012(Publication Date)
  • Princeton University Press

    (Publisher)

  The loss of predators generates strong imbalances shown by the disproportionate increase in the densities of prey and severe reductions of seedlings and saplings of canopy trees (Terborgh et al., 2001). It is well known that such a human-induced habitat alteration is the major variable leading to the loss of biodiversity (Wilcox and Murphy, 1985; Barbault and Sastrapradja, 1995). Some authors have estimated an increase of the extinction rates by 1,000 times during the last 300 years. These current rates of extinction are comparable in magnitude 172 C H A P T E R F I V E 0 0.2 0.4 0.6 0.8 1 Habitat destroyed 0 0.2 0.4 0.6 0.8 1 Regional abundance Extinction threshold 1650 1960 400 10 km 1086 b a F IGURE 5.1. Real and simulated Habitat Destruction. In (a) an example of habitat loss and fragmentation in a real ecosistem is shown through time. This example corresponds to the deforestation process experienced by native forests in Warwick-shire, England, between 400 and 1060 C.E. (adapted from Wilcove, 1987). In (b) the metapopulation regional abundance is plotted as a function of the amount of habitat loss for the Levins model. An extinction threshold takes place for a critical amount of habitat loss ( D c ) even when some habitat is still suitable. to one of the five big mass extinction events (Lawton and May, 1995; see chapter 7). If these estimations are correct, a species disappears from Earth on average every fifteen minutes. This means that at this rate, 1 million species may become extinct during the next twenty years. Given the magnitude and consequences of Habitat Destruction, it is imperative to get enough insight to understand the effects of habitat loss on species survival, and predict its further consequences. Since economic trade-offs are at play, scientists are oftentimes faced with the question of how much habitat can be destroyed before a certain species goes extinct.

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  Austral Ark

  The State of Wildlife in Australia and New Zealand

  • Adam Stow, Norman Maclean, Gregory I. Holwell(Authors)
  • 2014(Publication Date)
  • Cambridge University Press

    (Publisher)

  Deforestation has however slowed considerably since the 1870s, with the nationwide deforestation rate being just 0.01% per year between 1997 and 2002 (Ewers et al., 2006). 3.3 Ecological impacts of habitat loss and fragmentation 3.3.1 Abiotic impacts First, we explore how the physical fragmentation of habitat alters the abiotic conditions of the environment, before reviewing the known impacts of fragmentation on gene flow, the abundance of individuals, species diversity, species interactions, the movement of species between patches and ecosystem services. We conclude by examining evidence for how habitat loss and fragmentation might interact with introduced species to exert combined impacts on native biodiversity. Fragmentation can change the physical environment of fragments, with consequences for the organisms that live there. This impact can affect traits as diverse as the germination and early growth of the Kohekohe tree Dysoxylum spectabile (Young and Mitchell, 1994), composition of rainforest beetle assemblages (Grimbacher et al., 2006) and the reproduc- tive fitness of long-tailed bats, Chalinolobus tuberculatus (Sedgeley and O’Donnell, 2004). Figure 3.1 (Plate 24) The removal of native vegetation by people can leave remnant patches, often located along rivers or roads or difficult to develop areas such as steep hill sides. These habitat fragments are critical for the survival of native biodiversity, but altered biotic and abiotic conditions provide conservation challenges. A black and white version of this figure will appear in some formats. For the colour version, please refer to the plate section. Ecological consequences of habitat fragmentation 47 Studies conducted in the podocarp–broadleaf forests of Northland (Young and Mitchell, 1994) and the Atherton Tableland in north-eastern Queensland (Grimbacher et al., 2006) found generally consistent impacts of forest edges on microclimatic conditions.

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  Economic Growth, Biodiversity Conservation, and the Formation of Human Capital in a Developing Country (Volume 13.0)

  • Ludger Löning(Author)
  • 2018(Publication Date)
  • Peter Lang International Academic Publishers

    (Publisher)

  37 According to the United Nations Environment Programme (UNEP 2002), much of the available information is qualitative and anecdotal, and studies typically rely on habitat degradation. This includes the conversion of forests, classified by UNEP as the single most important factor causing loss of species in tropical and sub-tropical countries. Uncertainties in the assessment of biodiversity loss are, however, a function of uncertainty in the rate of deforestation itself. It is worth noting that there are a number of additional factors related to biodiversity loss. Among these are pollution, the unsustainable harvesting of natural resources, climate change, and the invasion of exotic species. The relative importance of these factors differs between regions and ecosystems. In terms of data availability and given the underlying causal structure of habitat loss in Guatemala, this study focuses on deforestation. The rational to see deforestation as a major cause of biodiversity loss is provided by the theory of island biography. McArthur and Wilson (1967) visualized the number of species on an island as a balance between species gains by 37 Biodiversity refers to the variability among all living organisms from all environments, including terrestrial, marine and other ecosystems, and the ecological complexes of which they are part. Following the UN Convention on Biological Diversity ( 1992), this includes diversity between species, within species and of ecosystems, as well as human cultural diversity. For details and a critique on the convention, see Brtihl (2002) as well as Boisvert and Caron (2002). Ludger Löning - 978-3-631-75357-6 Downloaded from PubFactory at 01/11/2019 05:58:33AM via free access 82 What Drives Habitat Loss in Guatemala? immigration and losses through extinction. 38 Using this concept, they developed a quantitative model to explain the number of species on islands.

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  Biodiversity Loss in a Changing Planet

  • Oscar Grillo, Gianfranco Venora, Oscar Grillo, Gianfranco Venora(Authors)
  • 2011(Publication Date)
  • IntechOpen

    (Publisher)

  12 Destruction of the Forest Habitat in the Tatra National Park, Slovakia Monika Kopecka Institute of Geography, Slovak Academy of Sciences Slovakia 1. Introduction The dynamically changing land cover configuration and its impact on biodiversity have aroused interest in the study of deforestation and its consequences. Deforestation is generally considered to be one of the most serious threats to biological diversity. Awareness of how different deforestation patterns influence habitat quality of forest patches is essential for efficient landscape–ecological management. The overall effect of deforestation on the forest patch depends on its size, shape and location. Zipperer (1993) identified the following types of the deforestation pattern:  Internal deforestation that starts in the forest patch and progresses outwardly;  External deforestation that starts outside and cuts into the forest patch, including indentation, cropping and removal;  Fragmentation when the patch is split into smaller parcels. Forest fragmentation is one of the most frequently cited causes of species extinction making it a crucial contemporary conservation issue. The classic view of a habitat fragmentation is the breaking up a large intact area of a single vegetation type into smaller landscape units or simply the disruption of continuity (Fahrig, 2003; Lord & Norton, 1990). This process represents a transition from being whole to being broken into two or more distant pieces. The outcome is landscape composed of fragments (e. g. forest) with something else (the non-forest matrix) between the fragments. Fragmentation of biotopes affects several ecological functions of landscape, first of all the spatial distribution of selected plant and animal species and associations (Bruna & Kress; 2002, Kurosawa & Askins, 2003; Parker et al., 2005).

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  Emerging Consequences Of Biotechnology: Biodiversity Loss And Ipr Issues

  Biodiversity Loss and IPR Issues

  • Krishna R Dronamraju(Author)
  • 2008(Publication Date)
  • World Scientific

    (Publisher)

  The agreement includes the following terms: • All scientists must ask for written permission to carry out studies, setting out a description of objectives, size and composition of Biodiversity Loss 105 ( Continued ) (Continued ) (Chapin 1998) the research party, length of research programme, species or object of study, and the manner in which this research will benefit the Awa community; • The request for permission must be given with a minimum of two months’ notice, since dispersed communities only meet four times a year for four days. • Research groups are limited to five people; • Local guides and informants must accompany all scientists; • The removal of any object from Awa territory not approved by the federation is prohibited; • Payments to the Awa Federation members for their services should be in accordance with a set of prices established by the Federation; • The Awa Federation must receive acknowledgement in all publications. Habitat Loss Human activities and climatic or biological factors, among other causes, have led to the universal phenomenon of ecosystem frag-mentation and, in some cases, total destruction. The present rate of human impact on biodiversity is unprecedented and is increas-ing dramatically. Humans have utilized and transformed over half of the land’s surface, and it is difficult to find any area that can be described as untouched by the human hand today. Habitat loss and fragmentation have greatly increased the threat to a large number of wild species that are facing total extinc-tion. Other species are threatened to varying degrees in different localities. It is precisely the local extinctions that are of concern to farm households. Local populations are adapted to the particular environment, while substitutes are not as well adapted to local conditions. 106 Emerging Consequences of Biotechnology (Continued ) (Kate 1995) Fragmentation Different ecosystems vary widely in their stability or relative invisi-bility.

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  Biodiversity

  A Beginner's Guide (revised and updated edition)

  • John Spicer(Author)
  • 2021(Publication Date)
  • Oneworld Publications

    (Publisher)

  About half (more for tropical regions) of the grasslands or savannahs, one quarter of scrublands, more than four fifths of wetlands, and even about a tenth of the desert regions (hot and cold) show some sort of human disturbance. Certainly, some of the practices of intensive commercial agriculture – the destruction of hedgerows, the elimination of weeds and insect pests – have had a massive effect on biodiversity, particularly in higher-income countries. While Habitat Destruction and degradation have been investigated in some detail, habitat fragmentation as a threat has not received the same amount of attention. An intact forest, woodland or meadow can be sectioned into small isolated bits by driving a road through the middle or effectively clearing strips of the habitat. Even though the area of habitat loss can be small, the fact that you now have a number of very small isolated ‘islands’ means that, because of the species–area relationship (remember Chapter 3 and the relationship between the number of species in an area and the size of that area), each section can only support a very small population. There are three issues with this. First, any negative chance events, such as disease or environmental change, will make such small populations more vulnerable to extinction than they would a larger population inhabiting the same overall habitat area. Second, if any of the species present, for whatever reason, actually needs a large habitat area, they are in trouble. And finally, we know that small areas of habitat are more influenced by their surroundings than large-area habitats, much in the same way as it would take an ice cube one cubic metre in size much longer to melt than it would one thousand separate ice cubes made from the big one

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  Global Action for Biodiversity

  An International Framework for Implementing the Convention on Biological Diversity

  • Timothy Swanson(Author)
  • 2013(Publication Date)
  • Routledge

    (Publisher)

  The early, human-induced extinctions have often been of those species which are most closely competing with humans, e.g. the large land mammals. The ranges of many of these species are usually restricted by the introduction of humans, and extinction sometimes results. Large land mammals are the most threatened initially, precisely because they compete most closely with humans in terms of range and resource requirements. The next set of extinctions occurred when other species, with less demanding requirements, have had their ranges vastly circumscribed, or even shifted. As on the oceanic islands, many species have taken refuge in some of the last remaining unaltered habitats, others have disappeared entirely. The third phase of the extinction process, i.e. the ‘biodiversity problem’, is the result of the workings of the human niche appropriation process toward these refugia. As this technological change diffuses to the final corners of the Earth, there must necessarily be an increasing rate of extinction.

  There is an empirically derived relationship, used by biogeographers, which relates the area of the available unmodified habitat to the number of species which it contains (Williamson, 1988). Studies of ‘islands’ of natural habitat, whether situated in oceans or civilisation, indicate that the number of species doubles with a tenfold increase in the area of the island. Conversely, a reduction in the size of the natural habitat by 90 per cent is likely to result in a halving of the number of species which it will contain. (MacArthur and Wilson, 1967).

  Again, the study of islands is instructive for looking at the global impact of conversions. This biogeographic relationship describes a geometric relationship between conversions and extinctions. That is, the rate of species loss is geometrically increasing with the actual amount of the total base resource appropriated by the human species. As the technology for conversions reaches the final refugia, there will be much greater losses of species per square hectare converted than occurred with the first, earlier conversions. This is what has been occurring on the global level, paralleling the island extinctions from which this relationship was derived.

  Land use alterations have been working across the globe for the past few millennia. Humans have been modifying lands for ten thousand years; however, the pace and diffusion of these alterations have been quickening in the past few hundred years. Estimates of aggregate natural habitat losses over the past two centuries range from 25 to 50 per cent (Myers, 1979; IIED, 1989). Since the commencement of the documentation of land-use changes (in the past thirty years), the pattern of current land conversions is clear. Two hundred million hectares of forest and 11 million hectares of grasslands were converted to specialised agriculture between 1960 and 1980 alone, all of it in the developing countries (Holdgate et al., 1982, Table 4.1

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  Wildlife Ecology, Conservation, and Management

  • John M. Fryxell, Anthony R. E. Sinclair, Graeme Caughley(Authors)
  • 2014(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  Fig. 21.2 ). It is scarcely surprising, therefore, that the strongest consistent effect on demography and biodiversity of wildlife is typically due to habitat loss itself, with much weaker effects typically arising from variation in patch size, patch isolation, and patch number (Andren 1994; Fahrig 2003). The devil is clearly in the details when it comes to habitat loss and fragmentation.

  21.3 Ecological effects of habitat loss

  While the pattern of habitat loss is often graphically obvious, the demographic implications might well be more subtle. Consider a lemur species whose feeding has evolved to specialize on a particular food plant. A change in the total forested area would represent a loss of a critical, essential resource for the specialized lemur. It is likely that such a change would lead to decline in the overall abundance of Madagascar lemurs. Destruction of some forest stands might well have little impact on the carrying capacity of the remaining stands, in which case local population density of lemurs would be little affected. Density-dependent interactions at a local level (home range spacing, population regulation, or consumer–resource interactions) might be little affected by habitat loss, provided the fragments are large enough to be inhabitable by sustainable local groups. On the other hand, theory suggests that local extinctions due to demographic stochasticity (see Chapter 16) should be dramatically increased if total population size within each patch declines at pronounced stages of habitat loss.

  Reviews of a large number of field studies strongly suggest that both total population size and local densities are often (but not always) reduced in ecosystems subjected to major habitat disturbance (Andren 1994; Fahrig 2003). Moreover, habitat loss is the most common contributory factor for endangered species (Wilcove et al. 1998). But habitat loss can also change the spatial configuration of habitat, which introduces its own set of problems.

  For example, many pool-breeding frogs and salamanders spend most of their adult life in forested environments. Pool-breeding species are sometimes reluctant to cross open, clear-cut patches compared to mature forest stands with abundant foliage at ground level (deMaynadier et al. 1999). If matrix habitat offers poorer probability of survival then increased loss of juveniles during dispersal can itself reduce population viability. Replicated experiments in logged versus unlogged landscapes in the United States indicate that survival and growth rate of juvenile and adult amphibians are consistently depressed by habitat disturbance (Semlitsch et al

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