Disturbance analyses of forests and grasslands with MODIS and Landsat in New Zealand

Beurs, Kirsten M. de; Julian, Jason P.

doi:10.1016/j.jag.2015.10.009

Cited by 17 publications

(7 citation statements)

References 32 publications

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“…On average, exotic forests are more disturbed than grasslands (18 months vs 3.8 months) [10], because the latter recover much faster. Connected disturbance increased significantly during the 2000-2004 period, where 65% of the forests in the Hoteo catchment were harvested.…”

Section: Nonlinear Changesmentioning

confidence: 98%

“…In order to assess land disturbance (times and areas of bare ground), we used an 8 day, 450 meter land cover dataset developed by de Beurs et al (2016) [10]. Details of the methodology can be found in their paper, but briefly, for each Moderate Resolution Imaging Spectroradiometer (MODIS) image, the Tasseled Cap transformation was calculated; by using the brightness, greenness, and wetness components based on the coefficients from Lobser and Cohen (2007) [43], a disturbance index (DI) ( Table 1) was calculated for every pixel.…”

Section: Land Cover/use and Disturbance Indexmentioning

confidence: 99%

“…Second, the required data to capture these phenomena are usually not available at the appropriate spatio-temporal resolution. For example, temporal resolution of readily-available land cover datasets usually limits researchers to assessing land cover/use on decadal or semi-decadal time-scales [8,9], when in reality, it can change on a weekly to monthly scale [10,11]. Spatially, suspended sediment or the related optical water quality variables of turbidity and visual water clarity are usually measured only at the catchment outlet, which can hide the effects of specific land-water relationships [12], although there are exceptions where sub-catchment analyses were conducted [13,14].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Nonlinear Changes in Land Cover and Sediment Runoff in a New Zealand Catchment Dominated by Plantation Forestry and Livestock Grazing

Kamarinas

Julian

Hughes

et al. 2016

Water

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Land cover can change frequently on intensively managed landscapes, affecting water quality across different spatiotemporal scales. Multi-resolution datasets are necessary in order to assess the extent and trends of these changes, as well as potential cross-scale interactions. In this study, both spatial and temporal analyses of land disturbance (i.e., soil exposure from vegetation removal) and water quality were performed on datasets ranging from daily to yearly time scales. Time-series analyses of land disturbance were compared against the water quality variables of total suspended solids (TSS), turbidity, and visual clarity for the Hoteo River catchment on the North Island of New Zealand for the 2000-2013 period. During forest harvest and recovery phases, exotic forests were the dominant disturbance, up to five times the area of grassland disturbance; while after recovery, grasslands assumed the dominant role, for up to 16 times the area of forest disturbance. Time-series of TSS from field sampling (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013) and TSS-event analyses (2012-2014) displayed distinct nonlinear patterns, suggesting that after major events, sediment that is stored in the landscape is exhausted and a period of sediment build-up follows until the next major event. Time-series analyses also showed a connection between trends in connected land disturbance and visual water clarity, with connected disturbance having the potential to be a water quality indicator. Future research should be conducted at even finer spatiotemporal scales over longer periods in order to identify effects of localized land disturbances on downstream water quality.

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Section: Nonlinear Changesmentioning

confidence: 98%

Section: Land Cover/use and Disturbance Indexmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Nonlinear Changes in Land Cover and Sediment Runoff in a New Zealand Catchment Dominated by Plantation Forestry and Livestock Grazing

Kamarinas

Julian

Hughes

et al. 2016

Water

View full text Add to dashboard Cite

show abstract

“…1, Healey et al, 2005) was developed to capture forest disturbances, which are assumed to lead to an increase in brightness and a decrease in greenness and wetness. This index was modified for grasslands (de Beurs et al, 2016), where disturbances are assumed to lead to a decrease in all three Tasseled Cap components (Eq.2). Our study region is characterized by brighter soils in steppe areas (Beznosov and Uspanov, 1960), in contrast to the soils for which the grassland DI was developed.…”

Section: Measuring Grazing Pressurementioning

confidence: 99%

“…Equation 2 Equation 3Prior to calculating the DIs, we normalized all three tasseled cap components to account for the different value ranges of each component (Healey et al, 2005, de Beurs et al, 2016. As the reference for this normalization, we used locations identified as 'ungrazed steppe' in the field.…”

Section: Equationmentioning

confidence: 99%