Spatial and temporal patterns of gap dominance by low-canopy lianas detected using EO-1 Hyperion and Landsat Thematic Mapper

Foster, Jane R.; Townsend, Philip A.; Zganȷar, Chris

doi:10.1016/j.rse.2007.07.027

Cited by 62 publications

(82 citation statements)

References 40 publications

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“…Various previous studies that applied CVA as a change detection algorithm for vegetation and soil used the tasseled cap's brightness and greenness [35,38,[63][64][65][66][67]. It is likely that both biophysical spectral variables would end up with close results.…”

Section: Discussionmentioning

confidence: 99%

Spatio-Temporal Dynamics of Land-Use and Land-Cover in the Mu Us Sandy Land, China, Using the Change Vector Analysis Technique

Karnieli

Qin

et al. 2014

Remote Sensing

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Abstract:The spatial extent of desertified vs. rehabilitated areas in the Mu Us Sandy Land, China, was explored. The area is characterized by complex landscape changes that were caused by different drivers, either natural or anthropogenic, interacting with each other, and resulting in multiple consequences. Two biophysical variables, NDVI, positively correlated with vegetation cover, and albedo, positively correlated with cover of exposed sands, were computed from a time series of merged NOAA-AVHRR and MODIS images (1981 to 2010). Generally, throughout the study period, NDVI increased and albedo decreased. Improved understanding of spatial and temporal dynamics of these environmental processes was achieved by using the Change Vector Analysis (CVA) technique applied to NDVI and albedo data extracted from four sets of consecutive Landsat images, several years apart. Changes were detected for each time step, as well as over the entire period (1978 to 2007). Four categories of land cover were created-vegetation, exposed sands, water bodies and wetlands. The CVA's direction and magnitude enable detecting and quantifying finer changes compared to separate NDVI or albedo difference/ratio images OPEN ACCESS Remote Sens. 2014, 6 9317 and result in pixel-based maps of the change. Each of the four categories has a biophysical meaning that was validated in selected hot-spots, employing very high spatial resolution images (e.g., Ikonos). Selection of images, taking into account inter and intra annual variability of rainfall, enables differentiating between short-term conservancies (e.g., drought) and long-term alterations. NDVI and albedo, although comparable to tasseled cap's brightness and greenness indices, have the advantage of being computed using reflectance values extracted from various Landsat platforms since the early 1970s. It is shown that, over the entire study period, the majority of the Mu Us Sandy Land area remained unchanged. Part of the area (6%), mainly in the east, was under human-induced rehabilitation processes, in terms of increasing vegetation cover. In other areas (5.1%), bare sands were found to expand to the central-north and the southwest of the area.

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Section: Discussionmentioning

confidence: 99%

Spatio-Temporal Dynamics of Land-Use and Land-Cover in the Mu Us Sandy Land, China, Using the Change Vector Analysis Technique

Karnieli

Qin

et al. 2014

Remote Sensing

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“…In many cases, lianas arrest tree regeneration, leaving gaps in a recalcitrant, low-canopy state for decades . These lianadominated, low-canopy sites can expand outward over time (Foster et al 2008), presumably when neighboring trees fall or are pulled into the gap by lianas (Young and Hubbell 1991). Lianas also reduce biomass accumulation in the intact forest, where they have an additional negative effect on forest-level biomass accumulation (e.g., Grauel and Putz 2004, van der Heijden and Phillips 2009, Tobin et al 2012.…”

Section: Lianas and Whole-forest Biomass Accumulationmentioning

confidence: 99%

“…Alternatively, lianas can proliferate rapidly in gaps soon after gap formation, where they compete intensely with trees, reducing tree recruitment, growth, diversity, and abundance (Putz 1984, Schnitzer and Carson 2001, Dalling et al 2012, Ledo and Schnitzer 2014. Lianas can thus redirect gap-phase regeneration away from a treedominated state to one where lianas are far more prevalent , Foster et al 2008 (Putz 1984, Schnitzer and Carson 2001, Ingwell et al 2010). Yet, in the BCI 50-ha forest dynamics plot, lianas constituted 25% of the rooted woody stem density (trees plus lianas) and 35% of the woody species diversity, but only 3% of the woody plant basal area .…”

Section: Introductionmentioning

confidence: 99%

Lianas in gaps reduce carbon accumulation in a tropical forest

Schnitzer

Heijden

Mascaro

et al. 2014

Ecology

114

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Abstract. Treefall gaps are the ''engines of regeneration'' in tropical forests and are loci of high tree recruitment, growth, and carbon accumulation. Gaps, however, are also sites of intense competition between lianas and trees, whereby lianas can dramatically reduce tree carbon uptake and accumulation. Because lianas have relatively low biomass, they may displace far more biomass than they contribute, a hypothesis that has never been tested with the appropriate experiments. We tested this hypothesis with an 8-yr liana removal experiment in central Panama. After 8 years, mean tree biomass accumulation was 180% greater in lianafree treefall gaps compared to control gaps. Lianas themselves contributed only 24% of the tree biomass accumulation they displaced. Scaling to the forest level revealed that lianas in gaps reduced net forest woody biomass accumulation by 8.9% to nearly 18%. Consequently, lianas reduce whole-forest carbon uptake despite their relatively low biomass. This is the first study to demonstrate experimentally that plant-plant competition can result in ecosystemwide losses in forest carbon, and it has critical implications for recently observed increases in liana density and biomass on tropical forest carbon dynamics.

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“…Rogers et al (2008) pool woody vines with other life forms. Foster et al (2008) provide incomplete information for their initial survey, which precludes an assessment of temporal change. Schnitzer and Bongers (2011) also cited an increase in the range of ivy in Germany, which we exclude because many free-standing species have also extended their ranges.…”

Section: Introductionmentioning

confidence: 99%

Long‐term changes in liana loads and tree dynamics in a Malaysian forest

Wright

Sun

Pickering

et al. 2015

Ecology

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Abstract. The importance of lianas through time and their effect on tree reproduction are evaluated for the first time in a Southeast Asian Dipterocarp forest. We quantified flower and seed production by lianas and trees for 13 years, assessed liana loads in the crowns of all trees larger than 30 cm in diameter at breast height (1.3 m) in 2002 and 2014, and assessed levels of reproduction for the same trees during a strong general flowering event in 2014 for the 50-ha forest dynamics plot at the Pasoh Forest Reserve, Malaysia. General flowering refers to synchronous reproduction by hundreds of plant species at irregular, multiyear intervals and only occurs in Southeast Asian Dipterocarp forests. Overall, lianas were present in 50% of tree crowns and comprised 31% of flower production and 46% of seed production. Lianas reduced growth, survival, and reproduction by their host trees. Lianas were less frequent in canopyemergent trees, Dipterocarps comprised a disproportionately large proportion of canopy emergents, and, as a consequence, lianas were less frequent in Dipterocarps than in trees from other plant families. Lianas infested the crowns of significantly fewer trees in 2014 (47.9%) than in 2002 (52.3%); however, the decrease was restricted to trees with the lightest liana loads and sample sizes and statistical power were enormous. Lianas comprised a stable proportion of flower production and a highly variable proportion of seed production from 2002 through 2013. We conclude lianas have a huge impact on trees in this forest and were a stable component of the forest between 2002 and 2014. The emergent habit and associated ability to avoid lianas might contribute to the success of the Dipterocarpaceae.

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Spatial and temporal patterns of gap dominance by low-canopy lianas detected using EO-1 Hyperion and Landsat Thematic Mapper

Cited by 62 publications

References 40 publications

Spatio-Temporal Dynamics of Land-Use and Land-Cover in the Mu Us Sandy Land, China, Using the Change Vector Analysis Technique

Spatio-Temporal Dynamics of Land-Use and Land-Cover in the Mu Us Sandy Land, China, Using the Change Vector Analysis Technique

Lianas in gaps reduce carbon accumulation in a tropical forest

Long‐term changes in liana loads and tree dynamics in a Malaysian forest

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