scholarly journals The MODIS Global Vegetation Fractional Cover Product 2001–2018: Characteristics of Vegetation Fractional Cover in Grasslands and Savanna Woodlands

2020 ◽  
Vol 12 (3) ◽  
pp. 406 ◽  
Author(s):  
Michael J. Hill ◽  
Juan P. Guerschman

Vegetation Fractional Cover (VFC) is an important global indicator of land cover change, land use practice and landscape, and ecosystem function. In this study, we present the Global Vegetation Fractional Cover Product (GVFCP) and explore the levels and trends in VFC across World Grassland Type (WGT) Ecoregions considering variation associated with Global Livestock Production Systems (GLPS). Long-term average levels and trends in fractional cover of photosynthetic vegetation (FPV), non-photosynthetic vegetation (FNPV), and bare soil (FBS) are mapped, and variation among GLPS types within WGT Divisions and Ecoregions is explored. Analysis also focused on the savanna-woodland WGT Formations. Many WGT Divisions showed wide variation in long-term average VFC and trends in VFC across GLPS types. Results showed large areas of many ecoregions experiencing significant positive and negative trends in VFC. East Africa, Patagonia, and the Mitchell Grasslands of Australia exhibited large areas of negative trends in FNPV and positive trends FBS. These trends may reflect interactions between extended drought, heavy livestock utilization, expanded agriculture, and other land use changes. Compared to previous studies, explicit measurement of FNPV revealed interesting additional information about vegetation cover and trends in many ecoregions. The Australian and Global products are available via the GEOGLAM RAPP (Group on Earth Observations Global Agricultural Monitoring Rangeland and Pasture Productivity) website, and the scientific community is encouraged to utilize the data and contribute to improved validation.

Insects ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 269
Author(s):  
Eleanor N. Field ◽  
Ryan E. Tokarz ◽  
Ryan C. Smith

The ecology and environmental conditions of a habitat have profound influences on mosquito population abundance. As a result, mosquito species vary in their associations with particular habitat types, yet long-term studies showing how mosquito populations shift in a changing ecological landscape are lacking. To better understand how land use changes influence mosquito populations, we examined mosquito surveillance data over a thirty-four-year period for two contrasting sites in central Iowa. One site displayed increasing levels of urbanization over time and a dramatic decline in Culex pipiens group (an informal grouping of Culex restuans, Culex pipiens, and Culex salinarius, referred to as CPG), the primary vectors of West Nile virus in central Iowa. Similar effects were also shown for other mosquito vector populations, yet the abundance of Aedes vexans remained constant during the study period. This is in contrast to a second site, which reflected an established urban landscape. At this location, there were no significant changes in land use and CPG populations remained constant. Climate data (temperature, total precipitation) were compiled for each location to see if these changes could account for altered population dynamics, but neither significantly influence CPG abundance at the respective site locations. Taken together, our data suggest that increased landscape development can have negative impacts on Culex vector populations, and we argue that long-term surveillance paired with satellite imagery analysis are useful methods for measuring the impacts of rapid human development on mosquito vector communities. As a result, we believe that land use changes can have important implications for mosquito management practices, population modeling, and disease transmission dynamics.


2019 ◽  
Vol 1 ◽  
pp. 1-1
Author(s):  
Roxanne Lai ◽  
Takashi Oguchi

<p><strong>Abstract.</strong> Changing land use is an increasingly important issue as human habits, behaviors, and needs change. There has been an increase in land and agricultural abandonment in some places of the world. In Japan, movement of the population from rural to urban areas have resulted in much land and agricultural abandonment. In 2016, a land ministry survey showed that 4.1 million hectares of land in Japan had unclear ownership, with farmland making up 16.9% of the total. As vegetation cover changes after land abandonment, this temporal and spatial effect may have important effects on geomorphic processes such as landslide susceptibility and landslide kinematics.</p><p>Here we track long-term land use changes over vegetated landslide areas of the Sanbagawa and Mikabu Belts of Shikoku Island, Japan. The Sanbagawa and Mikabu Belts are metamorphic belts that run across Southwest Japan, and are home to numerous large crystalline schist landslides, including the widely-studied slow but continuously moving Zentoku landslide. Villages and communities have been built on these landslide areas due to historical and cultural factors, as well as the fertility of the soil. Consequently, given the changing land uses including land abandonment in these landslide areas over time, we use long-term high-resolution land cover vegetation datasets to examine first the long-term land use changes, and then use statistical methods to explore their relationships with landslide susceptibility and kinematics. Mapping of spatial data and their analysis using GIS constitute a core part of the research. The results suggest interconnections between land use changes and land movement.</p>


2020 ◽  
Vol 9 (5) ◽  
pp. 324
Author(s):  
Jiaao Guo ◽  
Victoria Fast ◽  
Philip Teri ◽  
Kirby Calvert

Land-based, utility-scale renewable energy (RE) systems using wind or solar resources to generate electricity is becoming a decisive solution to meet long-term carbon emission reduction goals. Local governments are responding in kind, by adopting their own goals and/or establishing policies to facilitate successful implementations of RE in their jurisdiction. One factor to successful RE development is to locate the most suitable lands, while continuing to sustain land-based economies and ecosystem services. Local governments often have limited resources; and this is especially true for small, land-constrained local governments. In this paper, we illustrate how a standardized RE technical mapping framework can be used by local governments to advance the implementation of RE in land-constrained areas, through a case study in the Town of Canmore, Alberta. Canmore has a limited municipal area surrounded by the Canadian Rockies, along with complex land-use bylaw and environmentally sensitive habitats. This mapping framework accounts for these conditions as it considers theoretical resources, technically recoverable lands, legally accessible lands, and the spatial capital cost of connecting new RE facilities. Different land-use planning scenarios are considered including changing setback buffers and expanding restrictions on development to all environmentally sensitive districts. The total RE potentials are then estimated based on the least-conflict lands. Technically speaking, even under restrictive land suitability scenarios, Canmore holds enough land to achieve ambitious RE targets, but opportunities and challenges to implementation remain. To eventually succeed in its long-term emission reduction goal, the most decisive step for Canmore is to balance the growth of energy demands, land-use changes, and practicable RE development. Mapping systems that can study the influence of land-use planning decisions on RE potential are critical to achieving this balance.


2011 ◽  
Vol 52 (No. 6) ◽  
pp. 239-244 ◽  
Author(s):  
P. Kovář

The paper is focused on the impact of land use changes on water regime. First, an emphasis was given to what extent the main components of the water balance on the experimental catchment V&scaron;eminka (region Vset&iacute;nsk&eacute; Hills) were influenced. For this reason, the WBCM-5 model was implemented for the period of 10 years in a daily step with a particular reference to simulate the components of direct runoff and of subsurface water recharge. In the selected years of the period 1990&ndash;2000, the major changes were made in land use and also the significant fluctuation of rainfall-runoff regimes were observed (e.g. dry year 1992 and flood year 1997). After WBCM-5 parameter calibration it was found that some water balance components can change in relation to substantial land use changes even up to tens of percent in a balance-consideration, i.e. in daily, monthly and yearly or decade values, namely the components of interception and also of direct runoff and of subsurface water recharge. However, a different situation appears when investigating significant short-term rainfall-runoff processes. There were about seven real flood events analysed using the model KINFIL-2 (time step 0.5 hr) during the same period of about 10 years on the same catchment. Furthermore, some land use change positive or negative scenarios were also analysed there. As opposed to long-term water balance analyses, there was never achieved any greater differences in the hydrograph peak or volume than 10%. Summarising, it is always important to distinguish a possible land use change impact in either long-term balance or short-term runoff consideration, otherwise a misunderstanding might be easily made, as can often be found when commenting on the impact on floods in some mass media.


2020 ◽  
Vol 48 ◽  
pp. 2313-2328
Author(s):  
Koki Takayama ◽  
Yuichiro Watanabe ◽  
Hsiang-Chuan Chang ◽  
Akinori Morimoto

2017 ◽  
Vol 21 (1) ◽  
pp. 235-249 ◽  
Author(s):  
Antonio Hayas ◽  
Tom Vanwalleghem ◽  
Ana Laguna ◽  
Adolfo Peña ◽  
Juan V. Giráldez

Abstract. Gully erosion is an important erosive process in Mediterranean basins. However, the long-term dynamics of gully networks and the variations in sediment production in gullies are not well known. Available studies are often conducted only over a few years, while many gully networks form, grow, and change in response to environmental and land use or management changes over a long period. In order to clarify the effect of these changes, it is important to analyse the evolution of the gully network with a high temporal resolution. This study aims at analysing gully morphodynamics over a long timescale (1956–2013) in a large Mediterranean area in order to quantify gully erosion processes and their contribution to overall sediment dynamics. A gully network of 20 km2 located in southwestern Spain has been analysed using a sequence of 10 aerial photographs in the period 1956–2013. The extension of the gully network both increased and decreased in the study period. Gully drainage density varied between 1.93 km km−2 in 1956, a minimum of 1.37 km km−2 in 1980, and a maximum of 5.40 km km−2 in 2013. The main controlling factor of gully activity appeared to be rainfall. Land use changes were found to have only a secondary effect. A new Monte Carlo-based approach was proposed to reconstruct gully erosion rates from orthophotos. Gully erosion rates were found to be relatively stable between 1956 and 2009, with a mean value of 11.2 t ha−1 yr−1. In the period 2009–2011, characterized by severe winter rainfalls, this value increased significantly to 591 t ha−1 yr−1. These results show that gully erosion rates are highly variable and that a simple interpolation between the starting and ending dates greatly underestimates gully contribution during certain years, such as, for example, between 2009 and 2011. This illustrates the importance of the methodology applied using a high temporal resolution of orthophotos.


Oryx ◽  
1994 ◽  
Vol 28 (3) ◽  
pp. 173-182
Author(s):  
Jon C. Lovett ◽  
Erik Prins

The Kitulo Plateau of southern Tanzania is a lava plateau covering 273 sq km at an altitude of over 2500 m. The vegetation is predominately grassland with more than 350 taxa of vascular plants, of which nearly 5 per cent are of restricted distribution. Although the plateau is extensive, much of it is now cultivated. Digital analysis of satellite images showed that at least 24 per cent of the plateau was bare soil, modified grassland or cultivation between 1973 and 1989. The botanical importance of the plateau and increase in cultivation make a strong case for the establishment of a nature reserve to protect its rare and threatened plants.


2013 ◽  
Vol 129 (2) ◽  
pp. 85-99 ◽  
Author(s):  
Luca Salvati ◽  
Antonella De Angelis ◽  
Sofia Bajocco ◽  
Agostino Ferrara ◽  
Pier Matteo Barone

BioScience ◽  
2020 ◽  
Vol 70 (7) ◽  
pp. 597-609
Author(s):  
Chantel E Markle ◽  
Paul A Moore ◽  
James M Waddington

Abstract Identifying ecosystems resilient to climate and land-use changes is recognized as essential for conservation strategies. However, wetland ecosystems may respond differently to stressors depending on their successional state and the strength of ecohydrological feedbacks resulting in fluctuations in habitat availability and suitability. Long-term habitat suitability is necessary for the persistence of wetland-dependent species and a key characteristic of climatic refugia. In the present article, we review and synthesize biogeochemical, thermal, ecological, and hydrological feedbacks and interactions that operate within wetlands and, consequently, regulate overwintering suitability for many freshwater turtles and snakes. We propose that understanding the breadth and interconnected nature of processes controlling temperature, dissolved oxygen, and water table position are vital for the conservation of northern reptile populations that depend on wetlands to survive winter conditions. Finally, we suggest that our integrated framework can guide future research and the management of wetland ecosystems in an era of unprecedented change.


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