Characterizing Forest Fragments in Boreal, Temperate, and Tropical Ecosystems

Abstract

An increased ability to analyze landscapes in a spatial manner through the use of remote sensing leads to improved capabilities for quantifying human-induced forest fragmentation. Developments of spatially explicit methods in landscape analyses are emerging. In this paper, the image delineation software program eCognition and the spatial pattern analysis program FRAG-STATS were used to quantify patterns of forest fragments on six landscapes across three different climatic regions characterized by different moisture regimes and different influences of human pressure. Our results support the idea that landscapes with higher road and population density are more fragmented; however, there are other, equally influential factors contributing to fragmentation, such as moisture regime, historic land use, and fire dynamics. Our method provided an objective means to characterize landscapes and assess patterns of forest fragments across different forested ecosystems by addressing the limitations of pixel-based classification and incorporating image objects.

Forest Structure and Downed Woody Debris in Boreal, Temperate, and Tropical Forest Fragments

“…Three fragment size classes were selected based on field characterization and later classified and areas calculated using remote sensing software-see Meddens et al (19), and by photo interpretation of a subset of the fragments as a component of an associated decomposition experiment-see Gonza´lez et al (14). Overall mean fragment sizes were 104.5 ha (19.5 S.E.)…”

Length and classification of natural and created forest edges in boreal landscapes throughout northern Sweden

“…The length of edge was lower (49-61 m ha À1 ) in the two largest ecoregions (Boreal Plains and Boreal Shield) than in northern ecoregions with high proportion wetlands (106-121 m ha À1 ). In USA, Meddens et al (2008) reported more edge (60 m ha À1 ) in Minnesota than in Alaska (47 m ha À1 ). However, our estimate was lower than results by Löfman and Kouki (2001) from five managed forest landscapes in central Finland.…”

“…The high length of forest edges along roads indicate that roads may have large ecological impact in boreal forests (cf. Meddens et al, 2008), e.g. by affecting light and wind pattern into the forest.…”

“…The amount of edge peaked in the 1970s, after the introduction of clearcutting in the 1950s, but was still high in the 1990s, emphasizing that edge quantity may vary strongly over time. Meddens et al (2008) used Landsat Enhanced Thematic Mapper Plus (ETM+) images to quantify edges in boreal, temperate and tropical ecosystems. The most extensive study is that by Wulder et al (2008), which used Landsat ETM+ to characterize forest patterns at four spatial extents across Canada.…”

Lichen refugia within sub-boreal spruce forests: The role of riparian alder swales.

“…Similar suggestions have been made regarding hardwood establishment in other riparian systems (Wilson 1970;Stromberg et al 1991). At a larger scale, Meddens et al (2008) spatially analyzed landscape patches across North America, using roads, timber harvested areas, agricultural land, and urbanization to define edges of 23 forested patches. They found greater density of forested patches in the landscape and lower patch area in drier regions as compared to wetter regions.…”