A Cloud-Based Evaluation of the National Land Cover Database to Support New Mexico’s Food–Energy–Water Systems

Abstract

Accurate estimation of land use/land cover (LULC) areas is critical, especially over the semi-arid environments of the southwestern United States where water shortage and loss of rangelands and croplands are affecting the food production systems. This study was conducted within the context of providing an improved understanding of New Mexico’s (NM’s) Food–Energy–Water Systems (FEWS) at the county level. The main goal of this analysis was to evaluate the most important LULC classes for NM’s FEWS by implementing standardized protocols of accuracy assessment and providing bias-corrected area estimates of these classes. The LULC data used in the study was based on National Land Cover Database (NLCD) legacy maps of 1992, 2001, 2006, 2011, and 2016. The analysis was conducted using the cloud-based geospatial processing and modeling tools available from System for Earth Observation Data Access, Processing, and Analysis for Land Monitoring (SEPAL) of the Food and Agricultural Organization. Accuracy assessment, uncertainty analysis, and bias-adjusted area estimates were evaluated by collecting a total of 11,428 reference samples using the Open Foris Collect Earth tool that provided access to high spatial and temporal resolution images available in Google Earth. The reference samples were allocated using a stratified random sampling approach. The results showed an overall accuracy that ranged from 71%–100% in all six study counties. The user’s and producer’s accuracy of most LULC classes were about or above 80%. The obtained bias-adjusted area estimates were higher than those based on pixel counting. The bias-adjusted area estimates simultaneously showed decreasing and increasing trends in grassland and shrubland, respectively in four counties that include Curry, Roosevelt, Lea, and Eddy during the 1992–2016 period. Doña Ana county experienced increasing and decreasing trends in grassland and shrubland areas, respectively. San Juan county experienced decreasing trends in both grassland and shrubland areas. Cultivated cropland areas showed decreasing trends in three counties in southeast NM that rely on groundwater resources including Curry, Roosevelt, and Lea. Similarly, cultivated cropland areas showed increasing trends in the other three counties that rely on surface water or conjunctive use of surface and groundwater resources including San Juan, Doña Ana, and Eddy. The use of SEPAL allowed for efficient assessment and production of more accurate bias-adjusted area estimates compared to using pixel counting. Providing such information can help in understanding the behavior of NM’s food production systems including rangelands and croplands, better monitoring and characterizing NM’s FEWS, and evaluating their behavior under changing environmental and climatic conditions. More effort is needed to evaluate the ability of the NLCD data and other similar products to provide more accurate LULC area estimates at local scales.

Building an Improved Drought Climatology Using Updated Drought Tools: A New Mexico Food-Energy-Water (FEW) Systems Focus

“…However, during winter, summer, drought, and periods with extreme heat events, rangelands productivity decreases leading to increased demand for forage supplements to limit nutritional deficiency of grazing animals (Holechek et al, 2010;Samuelson et al, 2016). A recent study suggested that there have also been some land use land cover changes over some regions in New Mexico that can negatively affected the availability of suitable grazing rangelands that have been attributed mostly to woody plant encroachment (Gedefaw et al, 2020). These feed supplements are mostly based on irrigated and dryland production consisting mainly of combination of hay, grain sorghum, and corn (Schake et al, 1976;Davis et al, 1977;Holechek et al, 1989;Zaied et al, 2020).…”

“…New Mexico is specifically included in 11 of the Billion Dollar drought designations since 2000, and the threeyear 2011-13 period that severely affected New Mexico had an estimated $59.6 billion of losses nationally from the direct and indirect impacts that occurred (NOAA NCEI, 2020). For New Mexico, drought impacts affect crop and livestock productivity (Sawalhah et al, 2019;Zaied et al, 2019Zaied et al, , 2020Gedefaw et al, 2020); water supplies for public and ecosystem consumption; human, animal, and wildlife health; forests and wildfires; and recreation and tourism. These sectors have also become more vulnerable to natural hazards (i.e., droughts and wildfires) given changes occurring in the climate (NMOSE and NMWRRI, 2018).…”

Assessment of Rangeland Degradation in New Mexico Using Time Series Segmentation and Residual Trend Analysis (TSS-RESTREND)

“…There were relatively higher human activities in northeastern, northwestern and southeastern NM represented by crude oil and natural gas production and livestock grazing practices. The prevalence of irreversible degradation and initiation of degradation were apparent in these regions [63]. On the other hand, significant changes in productivity (i.e., increase) was observed mostly in southwestern and northwestern NM, where forest were minimally influenced by human activities.…”

Climate Change, Rangelands, and Sustainability of Ranching in the Western United States

“…The area of world rangeland ecosystems ( Figure 1) is being impacted by several opposing anthropogenic and natural processes that can result in (a) an increase in rangeland areas such as conversions of tropical forests into grazing lands, glaciated areas into rangeland, and cropland to rangeland due to climate change, soil degradation, and/or depletion of irrigation water supply from aquifers and drying of rivers [15]; or conversely (b) a decrease in rangeland areas such as conversion of arable rangelands into croplands, and rangelands into urban landscapes (e.g., [14]). For example, recent findings suggest that the depletion of large aquifers used for irrigation, such as the Ogallala in the Southern Great Plains of the US, is already causing shifts from cropland to rangeland [21].…”

“…Extreme weather events are already increasing in frequency and severity in the US and globally [5][6][7]. Global concern is growing over the possibility that eventual irreversible, catastrophic climate change will result in massive loss of human livelihoods and mortality through adverse impacts on food production systems over both croplands and rangelands [5,6,[8][9][10][11][12][13][14]. Rangelands globally account for 80-85% of feed needs for…”