Spatial persistence and temporal patterns in vegetation cover across Florida, 1982–2006

Tsai, Hui Ping; Southworth, Jane; Waylen, Peter R.

doi:10.1080/02723646.2014.898126

Cited by 12 publications

(13 citation statements)

References 142 publications

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“…An increase in late autumn and winter NDVI was found by Tsai et al . () in the state of Florida over the period 1982–2006 and was suggested to be caused by changes in the Atlantic multi‐decadal oscillation (AMO), which switched from a cold to a warm phase after 1995 and is associated with increased winter precipitation.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, the relationship between winter greening and changes in LULCC in central and south-eastern USA based on FAO statistics is inconclusive. An increase in late autumn and winter NDVI was found by Tsai et al (2014) in the state of Florida over the period and was suggested to be caused by changes in the Atlantic multi-decadal oscillation (AMO), which switched from a cold to a warm phase after 1995 and is associated with increased winter precipitation.…”

Section: Diverging Trends and Changes In Agricultural Practicementioning

confidence: 99%

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Global‐scale mapping of changes in ecosystem functioning from earth observation‐based trends in total and recurrent vegetation

Fensholt

Horion

Tagesson

et al. 2015

Global Ecology and Biogeography

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Aim To evaluate trend analysis of earth observation (EO) dense time series as a new way of describing and mapping changes in ecosystem functioning at regional to global scales. Spatio-temporal patterns of change covering 1982-2011 are discussed in the context of changes in land use and land cover (LULCC). Location Global.Methods This study takes advantage of the different phenological cycles of recurrent vegetation (herbaceous vegetation) and persistent vegetation (woody/shrub cover) in combining trend analyses of global-scale vegetation based on different annual/seasonal normalized difference vegetation index (NDVI) metrics. Spatial patterns of combined vegetation trends derived from the Global Inventory Modeling and Mapping Studies NDVI are analysed using land-cover information (GLC2000). ResultsThe direction of change in annual and seasonal NDVI metrics is similar for most global terrestrial ecosystems, but areas of diverging trends were also observed for certain regions across the globe. These areas are shown to be dominated by land-cover classes of deciduous forest in tropical/subtropical areas. Areas of observed change are found in dry deciduous forest in South America and central southern Africa and are in accordance with studies of hotspot LULCC areas conducted at local and regional scales. The results show that dense time series of EO data can be used to map large-scale changes in ecosystem functional type that are due to forest cover dynamics, including forest degradation, deforestation/ reforestation and bush encroachment. Main conclusionsWe show that areas characterized by changes in ecosystem functioning governed by LULCC at regional and global scales can be mapped from dense time series of global EO data. The patterns of diverging NDVI metric trends can be used as a reference in evaluating the impacts of environmental changes related to LULCC and the approach may be used to detect changes in ecosystem functioning over time.

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Section: Discussionmentioning

confidence: 99%

Section: Diverging Trends and Changes In Agricultural Practicementioning

confidence: 99%

Global‐scale mapping of changes in ecosystem functioning from earth observation‐based trends in total and recurrent vegetation

Fensholt

Horion

Tagesson

et al. 2015

Global Ecology and Biogeography

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“…Specifically, we utilize a measure called directional persistence, which indicates the overall direction of landscape change (increasing/decreasing) relative to a fixed benchmark condition (which could be tied to a climatic event, policy change, etc.) on a per pixel basis [45][46][47]. This metric is based on the principal of the random walk process, such that at any point in time, the likelihood of an increase versus a decrease in a value is identical (i.e., 0.5 probability) as this is a Bernouli random process.…”

Section: Remote Sensingmentioning

confidence: 99%

“…Theoretically, as NDVI is a continuous variable bounded by −1 and +1, identical values of NDVI are impossible. Predetermined critical levels of statistical significance, based on a random walk statistic, highlight the nature and extent of changes across the landscape beyond which might be expected at random and which are possibly indicative of degradation or other changes (see [45][46][47] for more details). The directional persistence (D j ) in this case yields a maximum range of −23 to +23 with the critical value of (α = 0.025) ±11 [45].…”

Section: Remote Sensingmentioning

confidence: 99%

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Understanding Long-Term Savanna Vegetation Persistence across Three Drainage Basins in Southern Africa

et al. 2018

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Across savanna landscapes of southern Africa, people are strongly tied to the environment, meaning alterations to the landscape would impact livelihoods and socioecological development. Given the human-environment connection, it is essential to further our understanding of the drivers of savanna vegetation dynamics, and under increasing climate variability, to better understand the vegetation-climate relationship. Monthly time series of Advanced Very High-Resolution Radiometer (AVHRR)-and Moderate Resolution Imaging Spectroradiometer (MODIS) derived vegetation indices, available from as early as the 1980s, holds promise for the large-scale quantification of complex vegetation-climate dynamics and regional analyses of landscape change as related to global environmental changes. In this work, we employ time series based analyses to examine landscape-level vegetation greening patterns over time and across a significant precipitation gradient. In this study, we show that climate induced reductions in Normalized Difference Vegetation Index (NDVI; i.e., degradation or biomass decline) have had large spatial and temporal impacts across the Kwando, Okavango, and Zambezi catchments of southern Africa. We conclude that over time there have been alterations in the available soil moisture resulting from increases in temperature in every season. Such changes in the ecosystem dynamics of all three basins has led to system-wide changes in landscape greening patterns.

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Delineating and characterizing changes in heat wave events across the United States climate regions

et al. 2023

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Exposure to extreme heat, or heat waves, represents a public health threat as well as an environmental health threat. With projections for further increases in temperature in some regions, resulting from global environmental change, it is important to understand the spatiotemporal impacts of heat waves in order to minimize risk. To understand heat wave impacts one cannot look solely at the spatial and temporal temperature regimes but much also consider key heat wave characteristics: duration, size, magnitude, frequency, and region of impact. To understand the consequences of heat wave events it is critical to analyze such extreme events based on the cumulative impacts of these characteristics. This study, which is conducted across the whole of the continental United States, looks to map, and analyze such cumulative impacts of heatwave characteristics. Heat waves were spatially de ned for the period of May-September of each year. Using persistence analyses and the development of a new index (Combined Heat wave Characteristics Index; CHCI) we can de ne regions of consistent heat wave exposure and impact.Results show that there are large differences across the United States in terms of heat wave exposure and impacting heat wave characteristics. Across much of the analysis a clear east versus west difference in patterns is seen. Overall, such work shows how and where differing, but covarying heat wave characteristics impact the United States. Information from this work can be combined with demographic and health metrics to better pinpoint susceptibility to heat waves -and therefore inform better management decisions.

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Spatial persistence and temporal patterns in vegetation cover across Florida, 1982–2006

Cited by 12 publications

References 142 publications

Global‐scale mapping of changes in ecosystem functioning from earth observation‐based trends in total and recurrent vegetation

Global‐scale mapping of changes in ecosystem functioning from earth observation‐based trends in total and recurrent vegetation

Understanding Long-Term Savanna Vegetation Persistence across Three Drainage Basins in Southern Africa

Delineating and characterizing changes in heat wave events across the United States climate regions

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