Modification of Land Cover in a Traditional Agroforestry System in Spain: Processes of Tree Expansion and Regression

Plieninger, Tobías; Schaar, Michael

doi:10.5751/es-02521-130225

Cited by 46 publications

(33 citation statements)

References 38 publications

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“…For example, birds and bats control insect pests (4)(5)(6), and trees provide shade for livestock (7,8). Scattered trees occurring throughout the farmland matrix are prominent features of agricultural landscapes around the world, including in southern Europe (9,10), North America (11,12), Central America (13)(14)(15), and Australia (16). Farmland trees often represent relicts of largely cleared forest or woodland ecosystems (17,18) and are believed to play important roles in maintaining ecosystem function and farmland biodiversity (7,13,16).…”

mentioning

confidence: 99%

Tree decline and the future of Australian farmland biodiversity

Fischer

Zerger²,

Gibbons

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

118

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Farmland biodiversity is greatly enhanced by the presence of trees. However, farmland trees are declining worldwide, including in North America, Central America, and parts of southern Europe. We show that tree decline and its likely consequences are particularly severe in Australia's temperate agricultural zone, which is a threatened ecoregion. Using field data on trees, remotely sensed imagery, and a demographic model for trees, we predict that by 2100, the number of trees on an average farm will contract to two-thirds of its present level. Statistical habitat models suggest that this tree decline will negatively affect many currently common animal species, with predicted declines in birds and bats of up to 50% by 2100. Declines were predicted for 24 of 32 bird species modeled and for all of six bat species modeled. Widespread declines in trees, birds, and bats may lead to a reduction in economically important ecosystem services such as shade provision for livestock and pest control. Moreover, many other species for which we have no empirical data also depend on trees, suggesting that fundamental changes in ecosystem functioning are likely. We conclude that Australia's temperate agricultural zone has crossed a threshold and no longer functions as a selfsustaining woodland ecosystem. A regime shift is occurring, with a woodland system deteriorating into a treeless pasture system. Management options exist to reverse tree decline, but new policy settings are required to encourage their widespread adoption.countryside biogeography | grassy box woodlands | ranchland | regime shift | scattered trees T he future of farmland biodiversity is a major concern around the world (1-3). Farmland biodiversity is valuable in its own right, but also because it provides ecosystem services that are of direct benefit to agricultural production. For example, birds and bats control insect pests (4-6), and trees provide shade for livestock (7,8). Scattered trees occurring throughout the farmland matrix are prominent features of agricultural landscapes around the world, including in southern Europe (9, 10), North America (11, 12), Central America (13-15), and Australia (16). Farmland trees often represent relicts of largely cleared forest or woodland ecosystems (17,18) and are believed to play important roles in maintaining ecosystem function and farmland biodiversity (7,13,16). Southeastern Australia's temperate agricultural zone is part of a threatened ecoregion (19) where farmland trees are declining rapidly. In cropping landscapes, trees are cleared to make way for agricultural machinery (20,21). In livestock grazing landscapes, trees are declining because of a combination of natural or accelerated tree mortality coupled with widespread recruitment failure (22). The decline of scattered trees is increasingly recognized as a threat to biodiversity and associated ecosystem services, both in the academic literature (7,17,20,(22)(23)(24) and increasingly in conservation policy (25).Scattered trees are declining not only in Australia, b...

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confidence: 99%

Tree decline and the future of Australian farmland biodiversity

Fischer

Zerger²,

Gibbons

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

118

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“…In addition, land-use transition analysis is generally limited to broad spatial occupancy changes (Plieninger and Schaar 2008). More subtle transformations within a land-cover category are rarely addressed though they have significant implications on the ecological functions, production potential, and symbolic value of landscapes (Plieninger and Schaar 2008). These implications are particularly true for wooded pastures characterized by a complex mosaic of herbage with various tree densities.…”

Section: Introductionmentioning

confidence: 99%

“…A spatially explicit approach based on geographic information sciences and integrating not only natural but also socioeconomic, political, technological, and cultural factors is therefore needed to produce more explanatory results (Krausmann et al 2003, Taillefumier andPiégay 2003). In addition, land-use transition analysis is generally limited to broad spatial occupancy changes (Plieninger and Schaar 2008). More subtle transformations within a land-cover category are rarely addressed though they have significant implications on the ecological functions, production potential, and symbolic value of landscapes (Plieninger and Schaar 2008).…”

Section: Introductionmentioning

confidence: 99%

A Contextual Analysis of Land-Use and Vegetation Changes in Two Wooded Pastures in the Swiss Jura Mountains

Chételat¹,

Kalbermatten²,

Lannas³

et al. 2013

E&S

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This study examines the effects of land-use policies and natural events on the evolution of two wooded pastures in the Jura Mountains in Switzerland between 1934 and 2000. The socioeconomic context and the local conditions were seen as major driving forces influencing land management practices which in turn redefined land-use policies. We studied the dynamics of the Jura Mountains' wooded pastures, combining a thorough knowledge of the historic context with aerial image analysis. Besides pointing out general milestones in the evolution of Swiss land policy, we compiled chronicles on the management for both study sites on the basis of archives and interviews. Aerial images taken at time intervals of approximately 15 years were chosen to identify land-cover changes. The method used to analyze them relied on a structural classification of phytocoenoses, thus allowing the determination of four categories of tree-cover densities ranging from unwooded pastures to ungrazed forest. We reported overall aerial changes for each tree density class as well as spatial transitions from one category to another. The combination of spatial statistics with qualitative data depicting the evolution of the historic context gives a better understanding of the land-use changes and their rationale. The most important changes in tree density occurred during World War II and resulted in a more open landscape. The intensive use of wooded pastures during the war was the consequence of a high demand for wood and food resources. Postwar protectionist regulations, agricultural subsidies, and technical improvements maintained considerable pressure on wooded pastures. Storms and drought episodes further exacerbated this process in some areas. The trend then reversed from the 1970s onwards because of the limitations put on milk production and the falling price of wood. This resulted in a more extensive use of pastures, leading to tree encroachment. However, remote sites were more impacted than pastures closer to inhabited areas, which exhibited a trend towards more segregation between grassland and densely wooded pastures. With both extensification and segregation of land use, the complex vegetation mosaic and the landscape diversity that characterize wooded pastures are threatened but still offer good economic opportunities that call for differentiated management strategies

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“…In many traditional cultural landscapes, sustainable management of natural resources resulted in landscapes with high aesthetic, ecological, and cultural values (Plieninger and Bieling 2012). Many ecosystem components of cultural landscapes directly depend on human use, including internationally protected species, habitats (Halada et al 2011, Wilson et al 2012, or specific landscape elements, e.g., wood pastures (Plieninger and Schaar 2008) and drove roads (OterosRozas et al 2013). …”

Section: Introductionmentioning

confidence: 99%