Four Decades of Land-Cover Change on the Kenai Peninsula, Alaska: Detecting Disturbance-Influenced Vegetation Shifts Using Landsat Legacy Data

Across Alaska’s Kenai Peninsula, disturbance events have removed large areas of forest over the last half century. Simultaneously, succession and landscape evolution have facilitated forest regrowth and expansion. Detecting forest loss within known pulse disturbance events is often straightforward given that reduction in tree cover is a readily detectable and measurable land-cover change. Land-cover change is more difficult to quantify when disturbance events are unknown, remote, or environmental response is slow in relation to human observation. While disturbance events and related land-cover change are relatively instant, assessing patterns of post-disturbance succession requires long term monitoring. Here, we describe a method for classifying land cover and quantifying land-cover change over time, using Landsat legacy imagery for three historical eras on the western Kenai Peninsula: 1973–2002, 2002–2017, and 1973–2017. Scenes from numerous Landsat sensors, including summer and winter seasons, were acquired between 1973 and 2017 and used to classify vegetation cover using a random forest classifier. Land-cover type was summarized by era and combined to produce a dataset capturing spatially explicit land-cover change at a moderate 30-m resolution. Our results document large-scale forest loss across the study area that can be attributed to known disturbance events including beetle kill and wildfire. Despite numerous and extensive disturbances resulting in forest loss, we estimate that the study area has experienced net forest gain over the duration of our study period due to reforestation within large fire events that predate this study. Transition between forest and graminoid non-forest land cover including wetlands and herbaceous uplands is the most common land-cover change—representing recruitment of a graminoid dominated understory following forest loss and the return of forest canopy given sufficient time post-disturbance.

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Analyses of Land Cover Change Trajectories Leading to Tropical Forest Loss: Illustrated for the West Kutai and Mahakam Ulu Districts, East Kalimantan, Indonesia

Land ◽

10.3390/land7030108 ◽

2018 ◽

Vol 7 (3) ◽

pp. 108 ◽

Cited By ~ 6

Author(s):

Carina van der Laan ◽

Arif Budiman ◽

Judith Verstegen ◽

Stefan Dekker ◽

Wiwin Effendy ◽

...

Keyword(s):

Land Cover ◽

Land Cover Change ◽

Large Scale ◽

Expert Knowledge ◽

Small Scale ◽

Forest Loss ◽

The West ◽

East Kalimantan ◽

Open Forest ◽

Over Time

In Indonesia, land cover change for agriculture and mining is threatening tropical forests, biodiversity and ecosystem services. However, land cover change is highly dynamic and complex and varies over time and space. In this study, we combined Landsat-based land cover (change) mapping, pixel-to-pixel cross tabulations and expert knowledge to analyze land cover change and forest loss in the West Kutai and Mahakam Ulu districts in East Kalimantan from 1990–2009. We found that about one-third of the study area changed in 1990–2009 and that the different types of land cover changes in the study area increased and involved more diverse and characteristic trajectories in 2000–2009, compared to 1990–2000. Degradation to more open forest types was dominant, and forest was mostly lost due to trajectories that involved deforestation to grasslands and shrubs (~17%), and to a lesser extent due to trajectories from forest to mining and agriculture (11%). Trajectories from forest to small-scale mixed cropland and smallholder rubber occurred more frequently than trajectories to large-scale oil palm or pulpwood plantations; however, the latter increased over time. About 11% of total land cover change involved multiple-step trajectories and thus “intermediate” land cover types. The combined trajectory analysis in this paper thus contributes to a more comprehensive analysis of land cover change and the drivers of forest loss, which is essential to improve future land cover projections and to support spatial planning.

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Detecting the impact of land cover change on observed rainfall

PeerJ ◽

10.7717/peerj.7523 ◽

2019 ◽

Vol 7 ◽

pp. e7523 ◽

Cited By ~ 1

Author(s):

Chun Xia Liang ◽

Floris F. van Ogtrop ◽

R. Willem Vervoort

Keyword(s):

Land Cover ◽

Land Cover Change ◽

Large Scale ◽

Southern Oscillation ◽

Rainfall Variability ◽

Tree Cover ◽

Trend Test ◽

South Central ◽

The Impact ◽

Step Trend

Analysis of observational data to pinpoint impact of land cover change on local rainfall is difficult due to multiple environmental factors that cannot be strictly controlled. In this study we use a statistical approach to identify the relationship between removal of tree cover and rainfall with data from best available sources for two large areas in Australia. Gridded rainfall data between 1979 and 2015 was used for the areas, while large scale (exogenous) effects were represented by mean rainfall across a much larger area and climatic indicators, such as Southern Oscillation Index and Indian Ocean Dipole. Both generalised additive modelling and step trend tests were used for the analysis. For a region in south central Queensland, the reported change in tree clearing between 2002–2005 did not result in strong statistically significant precipitation changes. On the other hand, results from a bushfire affected region on the border of New South Wales and Victoria suggest significant changes in the rainfall due to changes in tree cover. This indicates the method works better when an abrupt change in the data can be clearly identified. The results from the step trend test also mainly identified a positive relationship between the tree cover and the rainfall at p < 0.1 at the NSW/Victoria region. High rainfall variability and possible regrowth could have impacted the results in the Queensland region.

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Climate and land cover change impacts on stormwater runoff in large-scale coastal-urban environments

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.146017 ◽

2021 ◽

pp. 146017

Author(s):

Erfanul Huq ◽

Omar I. Abdul-Aziz

Keyword(s):

Land Cover ◽

Land Cover Change ◽

Large Scale ◽

Stormwater Runoff ◽

Urban Environments

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Thirty-two years of mangrove forest land cover change in Parita Bay, Panama

Forest Science and Technology ◽

10.1080/21580103.2021.1922512 ◽

2021 ◽

pp. 1-13

Author(s):

Yoisy Belen Castillo ◽

Kunhyo Kim ◽

Hyun Seok Kim

Keyword(s):

Land Cover ◽

Land Cover Change ◽

Mangrove Forest ◽

Forest Land ◽

Forest Land Cover

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Land Use Increases the Correlation between Tree Cover and Biomass Carbon Stocks in the Global Tropics

Land ◽

10.3390/land10111217 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1217

Author(s):

Manan Bhan ◽

Simone Gingrich ◽

Sarah Matej ◽

Steffen Fritz ◽

Karl-Heinz Erb

Keyword(s):

Land Use ◽

Land Cover ◽

Land Cover Change ◽

Land Management ◽

Empirical Relationship ◽

Carbon Stocks ◽

Tree Cover ◽

Ecosystem Structure ◽

Biomass Carbon ◽

Potential Vegetation

Tree cover (TC) and biomass carbon stocks (CS) are key parameters for characterizing vegetation and are indispensable for assessing the role of terrestrial ecosystems in the global climate system. Land use, through land cover change and land management, affects both parameters. In this study, we quantify the empirical relationship between TC and CS and demonstrate the impacts of land use by combining spatially explicit estimates of TC and CS in actual and potential vegetation (i.e., in the hypothetical absence of land use) across the global tropics (~23.4° N to 23.4° S). We find that land use strongly alters both TC and CS, with stronger effects on CS than on TC across tropical biomes, especially in tropical moist forests. In comparison to the TC-CS correlation observed in the potential vegetation (biome-level R based on tropical ecozones = 0.56–0.90), land use strongly increases this correlation (biome-level R based on tropical ecozones = 0.87–0.94) in the actual vegetation. Increased correlations are not only the effects of land cover change. We additionally identify land management impacts in closed forests, which cause CS reductions. Our large-scale assessment of the TC-CS relationship can inform upcoming remote sensing efforts to map ecosystem structure in high spatio-temporal detail and highlights the need for an explicit focus on land management impacts in the tropics.

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Hotter Drought Escalates Tree Cover Declines in Blue Oak Woodlands of California

Frontiers in Climate ◽

10.3389/fclim.2021.689945 ◽

2021 ◽

Vol 3 ◽

Author(s):

Francis K. Dwomoh ◽

Jesslyn F. Brown ◽

Heather J. Tollerud ◽

Roger F. Auch

Keyword(s):

Land Cover ◽

Land Cover Change ◽

Land Surface ◽

Climatic Variability ◽

Tree Cover ◽

Quercus Douglasii ◽

Oak Woodlands ◽

Vegetation Communities ◽

Blue Oak ◽

Climate Risks

California has, in recent years, become a hotspot of interannual climatic variability, recording devastating climate-related disturbances with severe effects on tree resources. Understanding the patterns of tree cover change associated with these events is vital for developing strategies to sustain critical habitats of endemic and threatened vegetation communities. We assessed patterns of tree cover change, especially the effects of the 2012–2016 drought within the distribution range of blue oak (Quercus douglasii), an endemic tree species to California with a narrow geographic extent. We utilized multiple, annual land-cover and land-surface change products from the U.S. Geological Survey (USGS) Land Change Monitoring, Assessment and Projection (LCMAP) project along with climate and wildfire datasets to monitor changes in tree cover state and condition and examine their relationships with interannual climate variability between 1985 and 2016. Here, we refer to a change in tree cover class without a land-cover change to another class as “conditional change.” The unusual drought of 2012–2016, accompanied by anomalously high temperatures and vapor pressure deficit, was associated with exceptional spikes in the amount of both fire and non-fire induced tree cover loss and tree cover conditional change, especially in 2015 and 2016. Approximately 1,266 km2 of tree cover loss and 617 km2 of tree cover conditional change were recorded during that drought. Tree cover loss through medium to high severity fires was especially large in exceptionally dry and hot years. Our study demonstrates the usefulness of the LCMAP products for monitoring the effects of climatic extremes and disturbance events on both thematic and conditional land-cover change over a multi-decadal period. Our results signify that blue oak woodlands may be vulnerable to extreme climate events and changing wildfire regimes. Here, we present early evidence that frequent droughts associated with climate warming may continue to affect tree cover in this region, while drought interaction with wildfires and the resulting feedbacks may have substantial influence as well. Consequently, efforts to conserve the blue oak woodlands, and potentially other vegetation communities in the Western United States, may benefit from consideration of climate risks as well as the potential for climate-fire and vegetation feedbacks.

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The Analysis of Forest Land Cover Change And Area Determination of Land Rehabilitation Based on Geographic Information System in Magelang Regency

E3S Web of Conferences ◽

10.1051/e3sconf/20187303004 ◽

2018 ◽

Vol 73 ◽

pp. 03004

Author(s):

Lidya Ernawati ◽

Sutrisno Anggoro

Keyword(s):

Information System ◽

Geographic Information System ◽

Land Cover ◽

Land Cover Change ◽

Geographic Information ◽

Forest Land ◽

Land Rehabilitation ◽

Forest Land Cover ◽

Area Determination

Population increased has consequences for the economic development of land demands for agriculture, settlement and other infrastructure. This resulted the change of area land cover which impact on the climate change and decline the environmental quality. Therefore, it is necessary to improve the environment through the land rehabilitation activities. The analysis of land cover change is needed as the first step to identify areas targeted by the land rehabilitation. Geographic information system is used as a spatial based on the appropriate determination of rehabilitation activities

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Satellite-Based Assessment of Grassland Conversion and Related Fire Disturbance in the Kenai Peninsula, Alaska

Remote Sensing ◽

10.3390/rs11030283 ◽

2019 ◽

Vol 11 (3) ◽

pp. 283 ◽

Cited By ~ 4

Author(s):

Katherine Hess ◽

Cheila Cullen ◽

Jeanette Cobian-Iñiguez ◽

Jacob Ramthun ◽

Victor Lenske ◽

...

Keyword(s):

Land Cover ◽

Land Cover Change ◽

Landsat Imagery ◽

Fire Danger ◽

Fire Disturbance ◽

Time Step ◽

Kenai Peninsula ◽

Spruce Beetle ◽

Grassland Conversion ◽

The Relationship

Spruce beetle-induced (Dendroctonus rufipennis (Kirby)) mortality on the Kenai Peninsula has been hypothesized by local ecologists to result in the conversion of forest to grassland and subsequent increased fire danger. This hypothesis stands in contrast to empirical studies in the continental US which suggested that beetle mortality has only a negligible effect on fire danger. In response, we conducted a study using Landsat data and modeling techniques to map land cover change in the Kenai Peninsula and to integrate change maps with other geospatial data to predictively map fire danger for the same region. We collected Landsat imagery to map land cover change at roughly five-year intervals following a severe, mid-1990s beetle infestation to the present. Land cover classification was performed at each time step and used to quantify grassland encroachment patterns over time. The maps of land cover change along with digital elevation models (DEMs), temperature, and historical fire data were used to map and assess wildfire danger across the study area. Results indicate the highest wildfire danger tended to occur in herbaceous and black spruce land cover types, suggesting that the relationship between spruce beetle damage and wildfire danger in costal Alaskan forested ecosystems differs from the relationship between the two in the forests of the coterminous United States. These change detection analyses and fire danger predictions provide the Kenai National Wildlife Refuge (KENWR) ecologists and other forest managers a better understanding of the extent and magnitude of grassland conversion and subsequent change in fire danger following the 1990s spruce beetle outbreak.

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