Percentage Of Vegetation Cover Research Articles

Stream Temperature and Environment Relationships in a Semiarid Riparian Corridor

This study examined the relationship between stream temperature and environmental variables in a semiarid riparian corridor in northcentral Oregon, USA. The relationships between riparian vegetation cover, subsurface flow temperature, and stream temperature were characterized along an 800 m reach. Multiple stream temperature sensors were located along the reach, in open and closed canopy areas, with riparian vegetation cover ranging from 4% to 95%. A support vector regression (SVR) model was developed to assess the relationship between environmental characteristics and stream temperature at the larger valley scale. At the reach scale, results show that air temperature was highly correlated with stream temperature (Pearson’s r = 0.97), and no significant (p < 0.05) differences in stream temperature levels were found among sensor locations, irrespective of percent vegetation cover. Channel subsurface temperature levels from an intermittent flow tributary were generally cooler than those in the perennial stream in the summer and warmer during winter months, indicating that the tributary may have a localized moderating effect on stream temperature. At the valley scale, results from the SVR model showed that air temperature, followed by streamflow, was the strongest variable influencing stream temperature. Also, riparian area land cover showed little effect on stream temperature along the entire riparian corridor. This research indicates that air temperature, subsurface flow, and streamflow are important variables affecting the stream temperature variability observed in the study area.

Influence of rainfall and seasonal crop practices on nutrient and pesticide runoff from soybean dominated agricultural areas in Pampean streams, Argentina

An increase in the spatial variability of rainfall is expected due to climate change. This implies increasing rainfall rates during spring and summer in the Pampas region, Argentina, period of maximum application of agrochemicals, which might cause an increase in pesticides and nutrients carried to surface water systems, as runoff by rainfall is one of the main pathways for diffuse pollution. The crops phenological stage can also affect pesticide and nutrient runoff since the applied agrochemicals and soil cover differ in each stage. In this study, we assessed the influence of rainfall and seasonal crop practices on water quality (nutrient and pesticide concentrations) in three streams in the Pampas region, Argentina. Five sampling campaigns were performed before and after three rainfall events during two different seasons of crop practices (SCP1, SCP2) and the physicochemical characteristics of the stream and runoff water were analyzed. The pesticide concentrations in the streams presented a general increase immediately after the rainfall event. Water quality was also affected, as an increase in ammonium, soluble reactive phosphorus (SRP), biological oxygen demand (BOD), and turbidity was observed. The crops phenological stage influenced pesticide and nutrient types and concentrations detected in the streams. During SCP1, mainly characterized by chemical fallow and sowing of soybean and vegetative growth and flowering of corn, ammonium, SRP, BOD, turbidity, and some pesticides, such as metolachlor, showed significantly higher results than those found in SCP2 (grain filling and vegetative growth of soybean and corn sowing). The pesticide concentrations detected in runoff water depended mostly on the pesticide solubility, the lateral slope of the streams, and the percentage of woody riparian vegetation cover. The results obtained show the relevance of assessing the influence of rainfall and crops phenological stages on the dynamics of surface water and on pesticide and nutrient runoff for environmental monitoring.

Improving the efficiency and accuracy of evaluating aridland riparian habitat restoration using unmanned aerial vehicles

AbstractUnmanned Aerial Vehicles (UAVs) offer new opportunities for accurate, repeatable vegetation assessments, which are needed to adaptively manage restored habitat. We used UAVs, ground surveys, and satellite imagery to evaluate vegetation metrics for three riparian restoration sites along the Colorado River in Mexico and we compared the data accuracy and efficiency (cost and time requirements) between the three methods. We used an off‐the‐shelf UAV coupled with a multispectral sensor to determine Normalized Difference Vegetation Index (NDVI) and vegetation cover. We were unable to accurately classify vegetation by individual species, but by grouping riparian species of interest (cottonwood‐willow, mesquite, shrubs), we achieved high overall model accuracies of 87–96% across sites (Kappa = 0.82–0.95). Producer’s and user’s accuracies were moderate to high for target vegetation classes (69–100%). UAV and ground‐survey vegetation percent cover differed due to differences in methodologies (UAVs measure aerial cover; ground surveys measure foliar cover) and sources of error for each method. Correlations between UAV and ground survey vegetation cover were moderate (rs(90) = 0.24–0.58, p < 0.05). UAV NDVI (0.50–0.61) was significantly higher than Landsat NDVI (0.40–0.45) for all sites (p < 0.0001), likely due to presence of shadows with high NDVI values in UAV imagery. UAV NDVI, Landsat NDVI and UAV total vegetation cover were strongly correlated (rs(90) = 0.72–0.85, p < 0.05). UAV surveys were more labor‐ and cost‐ intensive than ground surveys in the first year, but were slightly less so in the second year. We conclude that UAVs can provide efficient, accurate assessments of riparian vegetation, which can be used in restoration site management. Due to UAV limitations to assess vegetation in a multi‐layered canopy and inability to classify individual riparian species with similar spectral signals, we recommend a combined approach of UAV and ground surveys.

The effects of deficit irrigation practices on evapotranspiration, yield and quality characteristics of two sesame varieties (Sesamum indicum L.) grown in lysimeters under the Mediterranean climate conditions

In this study, we investigated the effects of deficit drip irrigation practices on evapotranspiration, water-yield relations, and quality characteristics of two sesame varieties (Muganli-57 and Birkan) grown in the lysimeters under the Mediterranean climate conditions. Irrigation treatments were rainfed (non-irrigated) (I0), drip irrigation with 25% (DI25), 50% (DI50), 75% (DI75), and 100% (DI100) of cumulative evaporation (Epan) measured in Class A pan with three replications. The applied water was corrected by the percentage of vegetation cover until the full cover was attained. Evapotranspiration of Muganli-57 and Birkan ranged from 157.8 to 518.8 mm and 156.4 to 509.2 mm, on average, respectively. The yield values changed between 0.46 and 2.06 t ha−1 in Muganli-57 and between 0.35 and 1.95 t ha−1 in Birkan. Based on the 2-year results, water use efficiency (WUE) of Muganli-57 variety (3.5 kg ha−1 mm−1) was numerically higher than that of the Birkan variety (3.4 kg ha−1 mm−1). In both varieties, it was determined that deficit irrigation generally reduced the yield. However, WUE did not decrease monotonically with decreasing irrigation level. DI50 treatment maximized WUE for two varieties in both years while DI75 maximized WUE for Muganli-57 in 2014. Although irrigation-variety interaction affected relative water content, chlorophyll content index, and seed dry matter, their effect tended to be weak and inconsistent between the 2 years of the study. Deficit irrigation decreased the oil content of sesame and increased its protein content. Similarly, deficit irrigation treatments decreased the linoleic acid content and increased oleic acid content in 1 year but not the other. It was concluded that the Birkan variety is more suitable for irrigated conditions due to the growth characteristics and less saturated fatty acid content. On the contrary, Muganli-57 variety is suitable for non-irrigated conditions in terms of water economy and fatty acid composition.

KAJIAN KONDISI BIOFOSIK LAHAN DAERAH ALIRAN SUNGAI DI SUBDAS CIUJUNG HULU, PROVINSI BANTEN

The upstream of a watershed is a buffer zone and it protects the whole watershed. The degradation of a watershed is caused by uncotrolled uses of the land and exploitation of the nature resources such as forest, land, and water. It causes the changes in the carrying capacity of the watershed, especially in biophysical aspects. This research aims to study the watershed biophysical condition in Ciujung Hulu Watershed, Banten Province. Biophysical condition analyzed using Forestry Minister Regulation P.61/Menhut-II/2014 for degraded land class, land cover percentage, and Erosion Hazard Index. The condition of the land, such as degraded land, vegetation cover, and erosion index, analyzed using modification of Forestry Minister Regulation Perdirjen BPDAS PS Nomor P.4/V-SET/2013. The result of the study showed that the percentage of degraded land, vegetation cover percentage, and erosion index were 25,85% (severe degraded land), 9,77% (very low covered), and 30,89 (Very high).

Matocompetição em pastagem de Panicum maximum BRS Tamani

Para a adoção de estratégias de manejo de plantas daninhas torna-se imprescindível o conhecimento dos períodos de interferência entre a comunidade infestante e a cultura de interesse econômico. Nesta pesquisa objetivou-se avaliar os efeitos da matocompetição na implantação da pastagem de Panicum maximum BRS Tamani e na rebrotação desta após o corte. Dois ensaios foram conduzidos em blocos ao acaso, com quatro repetições. No primeiro ensaio, a forrageira foi mantida em convivência com as plantas daninhas pelos períodos de 0, 7, 14, 21, 28, 35, 42, 49, 56 e 63 dias após a emergência (DAE) da pastagem, e no segundo ensaio, a forrageira foi mantida sem a convivência das plantas daninhas pelos mesmos períodos até o corte da forrageira, aos 63 DAE. As parcelas foram mantidas livres da convivência de plantas daninhas por capinas manuais, conforme tratamento. A matocompetição se estabeleceu logo após a emergência da forrageira e reduziu o rendimento de forragem. O período crítico de prevenção da interferência de plantas daninhas na pastagem de P. maximum BRS Tamani situou-se entre 1(um) e se estendeu até aos 42 DAE. A interferência de plantas daninhas diminuiu a produção da forragem, bem como a porcentagem de cobertura vegetal, altura do dossel e perfilhamento da forrageira.

The effect of some environmental variables on the abundance and distribution of aquatic macrophytes in Al-Hawizeh marsh, Iraq

Aquatic macrophyte communities and environmental factors were studied at four Al-Hawizeh marsh sites from December 2017 until November 2018. Quantitative data from thirty species of aquatic plants were collected to investigate density, vegetation cover, biomass and their relationship to the environmental factors. For emerging plants, relative abundance reached the highest values (36%) than submerged and wet species, while free-floating plants produced the lowest value (17%).Physical and chemical properties have been studied including water temperature ranging from 11.3 ° C in January to 31.4 ° C in August, dissolved oxygen (DO)ranging from 1.88 mg/L in September to 10.5 mg / L in April, pH varied from 7.2 in June to 8.4 in December, electrical conductivity (EC μ.S/cm) differs from 2257 μ.S/cm in November to 6859 μ.S/cm in April. The results identified the highest percentages of vegetation cover reported during the summer, the lowest percentages revealed during the winter for all plant groups. The highest annual vegetation cover rates for submergent species achieved 52.54% by C.demersum, for free-floating plants 66.67% of S. polyrrhiza, for emergent plants 85.5% of P. australis, 41.62% of P. paspaloide for wet plants. Total mean biomass of plant groups showed the highest value of 844.02 (gm dry weight/m2) reported by emerging plants, the lowest value of 47.25 (gm dry weight / m2) by the wet plants. Thus, biomass values were correlated with the vegetation cover values for all plants.

Іле өзенінің жоғарғы ағысында сирек кездесетін, эндемдік Rosa iliensis Chrshan. популяциясының өсімдіктер жабынының геоботаникалық сипаттамасы

The article gives a geobotanical characterization of plant communities of the population of the rare, endemic plant Rosa iliensis in the floodplain of the river Ili. The assocations of three cenopopulations and the percentages of vegetation cover in this population, the vegetation cover of tiers, are also described. Within each cenopopulation, a 10×10 transect was constructed and the age structure of the vegetation cover in it was determined. In the upper reaches of the river or the state of life of Rosa iliensis can be called satisfactory. Because here Rosa iliensis blooms and bears fruit every year. However, not a single seedling of this plant was found within the populations. This indicates that Rosa iliensis in natural conditions propagates by seeds extremely rarely and its renewal is mainly vegetative, root offspring. Taking this into account, we suggest that the floodplain of the upper Ili river, where the population of Rosa iliensis is found, conduct constant monitoring work and thereby keep the state of its population under control. In addition, we offer Rosa iliensis Chrshan. to be introduced in the main botanical garden of Almaty and the Ili Experimental Botanical Garden of the Balkhash district of Almaty region.

Associations of objective and perceived greenness measures with cardiovascular risk factors in Philadelphia, PA: A spatial analysis

There is mounting scientific evidence that greenness is associated with improved cardiovascular health. However, few studies have distinguished between vegetation type, measured perceived green space access, or investigated heterogeneity of associations across categories of neighborhood sociodemographic and racial/ethnic composition. We conducted an ecologic spatial analysis of associations of three objective measures of greenness (percent vegetation cover, percent tree canopy cover, and greenness density), and one measure of perceived access to green spaces with census tract level percentages of the adult population who were obese, ever had a high blood pressure diagnosis, and ever had a diabetes diagnosis, in the city of Philadelphia, PA, year 2013. We explored effect modification by census-tract level percent living in poverty and percent non-Hispanic Black categories. We used data from the Southeastern Pennsylvania Household Health Survey (SEPAHH) linked with high-resolution landcover, remotely sensed, and American Community Survey data and estimated associations using spatial lag models. We observed modest protective associations between percent of the adult population reporting perceived access to green spaces and percent with the cardiovascular risk factors, particularly in moderate and high poverty census tracts. Percent tree canopy cover was also protective against the cardiovascular risk factors, particularly in census tracts with low percentages of the population living in poverty and with low percent non-Hispanic Black populations. These results suggest that perceived access to green spaces and objectively measured high tree canopy cover, may protect against cardiovascular disease, but associations may vary across neighborhood sociodemographic categories.

Changes in vegetation cover and connectivity of private gardens at traditional wooden townhouses in the ancient city of Kyoto

A large number of Kyoto’s traditional wooden townhouses (referred to here as “KWTs”; kyo-machiya in Japanese), characterized by various types of gardens, have been demolished in recent years as lifestyles have changed. Against a background of limited research into the ecological status of such gardens (referred to here as “KWT gardens”), the authors investigated related changes in a school district where numerous KWTs have been removed, although many still remain, based on the aerial photographs of the local area and related distribution data. The results indicated that KWT gardens as a percentage of overall vegetation cover (“VC”) decreased from 39 to 28% between 1987 and 2008, and that separation/miniaturization of green spaces had progressed. However, some KWT gardens still remained at new houses renovated from KWTs. It was found that, although VC and the connectivity of KWT gardens had decreased due to KWT demolition, such areas still represent a significant part of VC in the ancient city of Kyoto. Accordingly, it is necessary to evaluate remaining KWT gardens and promote their preservation as cultural and ecological assets.

Cobertura vegetal y la distribución de islas de calor/oasis urbanos en Hermosillo, Sonora

The case of an arid Northwest city of Mexico is studied with the general objective of assessing the influence of the percentage of vegetation cover (VC) in Land Surface Temperature (LST) and mapping its spatial distribution, through a geographic information system using remote sensing data. Results showed: 1) on average, 12% (min. 0 to max. 59%) of a city block is covered with vegetation, 38% of the blocks had % VC ≤ 10; 2) the LST regression model estimated temperatures range from 37 to 45°C, the main explanatory variable was % VC, increasing % VC in 10 is associated with cooling effect of 1.1 °C. The spatial heterogeneity in the distribution of LST can be interpreted as the human effect modifying the climate on a small scale; this creates internal diurnal oasis.

SURFACE RUNOFF IN TWO REHABILITATION PERIODS OF A BAUXITE MINE

ABSTRACT The objective of this study was to monitor and compare runoff at 2.5 and 3.5 years of rehabilitation of a mined bauxite area with clonal planting of Eucalyptus. Seven plots were allocated for collecting runoff and precipitation was recorded with a pluviograph. The physical and environmental factors which interfere with runoff were characterized in both periods and subjected to principal component analysis (PCA) to show the most explanatory factors. The average monthly runoff percentage at 2.5 years was 0.25% (± 0.26%) of precipitation and equal (p-value<0.05) to the 3.5 years (0.15 ± 0.22%) of rehabilitation. Both values were lower than the Eucalyptus plantation area without mining (0.56%) in the same region and declivity. The high vegetation cover percentage by Eucalyptus crowns and Brachiaria sp. and the high infiltration rates were the determining factors in PCA, and may explain the statistically equal runoff values between the rehabilitation periods. The combination of good edaphic conditions and the fast coverage of the plants resulted in runoff below 1% in a rehabilitated area after bauxite mining.

Dynamic change and prediction of vegetation cover in Shenzhen, China from 2000 to 2018

With landsat-series multi-temporal image data, percentage of vegetation cover (PVC) was estimated by pixel dichotomy. The linear regression analysis and center of gravity migration methods were used to explore the characteristics of the spatiotemporal changes of vegetation cover in Shenzhen from 2000 to 2018. The CA-Markov model was combined to predict future land cover in Shenzhen. The results showed that the PVC in Shenzhen demonstrated obvious regional differentiation characteristics from 2000 to 2018. The eastern region occupied larger proportion than the wes-tern part, while the southern region was larger than the north part. This feature exhibited good consistency with regional topographic effect. The spatial migration characteristic of the center of gravity of PVC was from northwest to southeast, and then from southeast to northwest, with a migration rate of 551.2 m·a-1. This process was closely related to urbanization in Shenzhen. The PVC in Shen-zhen tended to be generally improved from 2000-2018, with a improvement rate of 0.005·a-1. The percentage of significantly improved and degraded PVC area was 30.8% and 12.8%, respectively. The CA-Markov method was used to predict the land cover/use pattern of Shenzhen in 2024 under two scenarios, theoretical scenario and natural scenario. There was no significant difference in proportion of the area of the land cover/use patterns obtained by the two kinds of prediction method, with the difference threshold being 0-1.2%. Compared with the data before 2018, the proportion of arbor forests and arable land converted into construction land in Shenzhen would be significantly reduced in 2024, whereas the contradiction between supply and demand would be still tense.

A High Spatial Resolution Satellite Remote Sensing Time Series Analysis of Cape Bounty, Melville Island, Nunavut (2004–2018)

Changes in vegetation have been observed in areas of the Arctic due to changing climate. This study examines a normalized difference vegetation index (NDVI) time series (2004–2018) of high spatial resolution satellite data (i.e., IKONOS, WorldView-2, WorldView-3) to determine if vegetation abundance has changed over the Cape Bounty Arctic Watershed Observatory, Melville Island, Nunavut. Image data were corrected to top-of-atmosphere reflectance and normalized for time series analysis using the pseudo-invariant feature (PIF) method. Percent vegetation cover measurements and indices derived from local climate data (growing degree days base 5 °C; GDD5) were used to contextualize NDVI trends in different vegetation types and within active layer detachments (ALDs). NDVI showed similar patterns within the different vegetation types and across the ALDs. There was no significant change in NDVI nor in GDD5 over time. However, there were statistically significant (p < 0.05) relationships between the GDD5 and NDVI for all vegetation types. Using field measurements with high spatial resolution remote sensing data helps link changes in NDVI with changes to vegetation and earth surface processes. The challenges of integrating high spatial resolution satellite data from different sensors in a time series analysis are also discussed.

Investigation of land surface phenology detections in shrublands using multiple scale satellite data

Shrublands occupy about 13% of the global land surface, contain about one-third of the biodiversity, store about half of the global terrestrial carbon, and provide many ecosystem services to a large amount of world's human population and livestock. Because phenology is a sensitive indicator of the response of shrubland ecosystems to climate change, the alteration of ecosystems following species invasions, and the dynamics of shrubland ecosystem function, biodiversity, and carbon budgets, it is critical to monitor and assess phenological dynamics in shrubland ecosystems. However, most current land surface phenology (LSP) products derived from satellite data do not provide phenology detections in some semiarid shrublands where the amplitude of seasonal vegetation greenness is small. Therefore, we investigated the LSP detection using multiple spatial resolution satellite data and examined the impacts of spatial scales and shrubland ecosystem components (shrub and herb cover) on LSP detections over the western United States. Specifically, greenup onset date (GUD) in shrublands was detected from 30 m Harmonized Landsat and Sentinel-2 (HLS) data and 500 m Visible Infrared Imaging Radiometer Suite (VIIRS) data to quantify scale effects. The GUD spatial patterns were explored with 30 m pixel variations in shrubland ecosystem components. The results show that GUD values varied with percent vegetation cover and shifted to earlier dates with increasing vegetation cover, demonstrating that satellite observations were not able to capture greenup onset until a threshold of green vegetation cover is reached. GUD was mostly undetectable from both HLS and VIIRS pixels with vegetation cover less than 10% and became fully detectable with vegetation covers larger than 50%. Similarly, the differences of GUD between HLS and VIIRS detections also decreased with increased vegetation cover. As a result of high shrubland heterogeneity, GUD from 30 m HLS pixels could be partially detected within a 500 m pixel despite GUD being undetectable from VIIRS time series. Moreover, vegetation cover heterogeneity also made it difficult for GUD at 30 m to be aggregated to coarse scales (such as to 500 m VIIRS pixels). These findings have significant implications to the detection and characterization of shrubland LSP responses to environmental and climate changes.

What does Atlantic Forest soundscapes can tell us about landscape?

The ecoacoustics approach for environmental recordings analysis is used to understand and identify big ecological patterns related to different sound sources, like animals, humans and the environment itself. Sounds can vary according to several features that can be on its surroundings or far away, therefore they are very much reliant on scale. Because humans are changing the environment so much and we cannot account for all those changes in the same speed as they happen, we need fast evaluation tools, such as remote sensing and acoustic monitoring (considered the equivalent of spatial remote sensing for sounds). Considering that the scale of effect was never measured for soundscapes before, we aimed to see in what scale different acoustic indices were responsive. Also, we tested how acoustic indices are influenced by natural vegetation cover. We recorded environmental sounds in Atlantic Forest fragments during three months on the rainy season. Then we calculated different acoustic indices and the percentage of natural vegetation cover in different scales. Our results corroborated our initial hypotheses: different indices respond to different scales and their medians varied according to the amount of vegetation cover on the surroundings. More studies are needed with less fragmented areas, to test indices behaviour in a continuum, but we consider this work an important starting point to understand acoustic indices behaviour in tropical areas, especially in such degraded and threatened area as Atlantic Forest.

Distribution, habitat suitability, conservation state and natural history of endangered salamander Bolitoglossa pandi.

BackgroundPandi’s mushroom-tongue salamander (Bolitoglossa pandi) is one of the threatened amphibians in South America, as well as a flagship species for the Colombian conservation agenda. This species is endemic to the Andean cloud forests of the western slope of the Cordillera Oriental of Colombia, occurring only in the department of Cundinamarca within a narrow elevational range. At night, B. pandi can be seen perching on the upper side of leaves at heights ranging from ground level to 2.5 m. During the day, it can be found under leaf litter or cover objects. Few studies have provided relevant information that can help the Colombian government to formulate lines of action for the conservation of this species; consequently, its threat assessments so far have been based on very limited information.MethodsWe conducted surveys for salamanders in four municipalities of Cundinamarca, Colombia, using two approaches: visual encounter surveys (Guaduas and Villeta) and the basic sampling protocol for single-species occupancy modeling (Supatá and Venecia). Multivariate analyses were employed to explore the correlation between habitat structure and natural history traits, abundance, and detection/non-detection of B. pandi. We evaluated the B. pandi activity pattern through kernel density curves for each sampling occasion and explored the variability of salamander abundance during their activity period by performing a nested ANOVA.ResultsWe report the discovery of two new populations of B. pandi, which represent the most northwestern records known. A significant correlation between body length, body mass, and habitat structure was observed. Multivariate analyses indicated that leaf litter depth, mean temperature, percent vegetation cover, and altitude were the habitat variables that together explained 60.3% of the B. pandi abundance variability, as well as the main determinants of its optimal habitat. Bolitoglossa pandi exhibits an activity pattern characterized by two main activity peaks, in which niche time-partitioning was observed. Across the surveyed area, we found a healthy, stable, highly dense population of B. pandi (>1,300 individuals), with seasonal variability between development stages.DiscussionGiven the high habitat specificity of B. pandi, the species is highly vulnerable to local changes. Thus, we recommend that B. pandi be retained as Endangered (EN) on the IUCN Red List, based on the IUCN Criterion B, given its restricted extent of occurrence (ca. 2,500 km2) and the ongoing threats from agriculture, cattle ranching, logging, and urban development, which continue to reduce its suitable habitat.

Prediction of future grassland vegetation cover fluctuation under climate change scenarios

Grasslands are subject to degradation in arid and semi-arid areas as the result of various pressures, including climate change. Therefore, spatial and temporal monitoring of vegetation cover fluctuation is needed for better understanding and management of natural resources to sustain livelihoods that depend on these grasslands. In this study, changes in vegetation cover were monitored over 1985–2015, using vegetation indices derived from the Landsat images in Chaharmahal-va-Bakhtiyari province, Iran. The percentage of vegetation cover was recorded from sampling plots in the study areas and vegetation indices were calculated from Landsat data over the study period. The relationship between vegetation cover and climate parameters (temperature (T) and precipitation (P)) was determined from precipitation maps, produced from spatial interpolation of weather stations data and temperature maps, produced by regression equation established between DEM-derived elevation and temperature. Then, a regression equation between climate variables and vegetation cover over a period of 30 years’ period was developed and applied on projected climatic variables for the 2050 under RCP2.6 and RCP8.5 scenarios. The Green Vegetation Index (GVI) was found to be the best index for estimation of vegetation cover from the correlation coefficient (r = 0.79) and model RMSE (1.98). The GVI fluctuation was associated with the fluctuation in climate variables, and this was especially evident in especially dry years (1999, 2001 and 2012). From the difference between current and future vegetation cover maps, future vegetation cover change maps were produced and vulnerable areas most likely to be impacted by climate change were identified. The results predict that vegetation cover will be reduced under both scenarios, mostly in the eastern parts of the study region, while 5–25% of vegetation cover increases are projected for some areas in the western parts of the region. Further analysis showed that currently, oak forest covers large swaths of the western parts adjacent to grasslands, but forest degradation will lead to increase of grassland areas at the expense of oak forests. Overall, substantial loss of vegetation cover is predicted in the central parts and extends to the southern parts of the province. Loss of vegetation cover would pave the way to conversion of grassland to other non-productive cover types for pastoral systems. Appropriate management programs and adaptation strategies should be designed and implemented to reduce climate change impacts on grasslands in the identified vulnerable areas.

Effectiveness of re-vegetated forest and grassland on soil erosion control in the semi-arid Loess Plateau

Afforestation reduces soil loss and minimizes landslide risk worldwide, but little is known on the effectiveness of afforestation policies to control soil erosion with different vegetation types in semi-arid areas. Understanding the effectiveness of distinct re-vegetation types under different physiographic conditions (slope gradient, percentage of vegetation cover and rainfall depth) is essential for better policy formulation. This study examines the benefits of soil erosion control in forests and grasslands using published data. This analysis proves that the benefits of vegetation restoration increase with increasing the vegetation cover and tend to be stable when the coverage exceeds 60%. The benefits on sediment yield reduction are more sensitive (vs. runoff reduction benefit) to rainfall intensity. Regarding slopes and soil erosion control, the highest efficiencies appear in forests on 20–25° slopes and in grasslands on 15–20° slopes. Grasslands can effectively reduce soil erosion, as well as forests with understory grasses. For long-term restoration, a 60% vegetation cover maximizes the benefits of reducing soil erosion and maintaining enough soil water supply that prevents possible soil drought. We propose that future afforestation policies should evaluate in advance the appropriate re-vegetation type; meanwhile, suitable vegetation coverage and local physiographic conditions should be considered. Importantly, promotion of grassland and preservation of forest understory grasses must be enforced in land use policies when considering afforestation to minimize soil erosion. We suggest further research to quantify the efficiency of understory vegetation on soil erosion control, which might provide scientific and practical guidance for afforestation policy in semi-arid areas.

Reclassifying the Wildland–Urban Interface Using Fire Occurrences for the United States

The wildland–urban interface (WUI) occurs at the intersection of houses and undeveloped wildlands, where fire is a safety concern for communities, motivating investment in planning, protection, and risk mitigation. Because there is no operational definition of WUI based on where fires in fact have occurred, I used fire occurrences to objectively establish a definition of WUI, while examining spatiotemporal changes, for the conterminous United States. I applied four classifiers, but focused on C5.0, which produced equivalent sensitivity (0.87 to 0.91 at prevalence = 0.67) and generated a ruleset that indicated housing density was the preferable basis for definitions. Fire occurrences overall were predicted for housing densities &lt;100 houses/km2 with potentially low (≥10%) thresholds for percent vegetation cover, varying by housing densities and models. A generalized guideline according to classifications is continued use of existing definitions for wildlands of &lt;6.17 houses/km2 and a low-density intermix class of 6.17 to 50 houses/km2. Departing from other definitions, the medium-density class encompasses 50 to 100 houses/km2 and the high-density class is 100 to 200 houses/km2. Interface, or suburban, communities are 200 to 400 houses/km2. Implications of refining the definition include a larger critical area classified as greater fire risk (low and medium-density WUI below 100 houses/km2) at 855,000 km2 during 2010, and; therefore, incorporation of more communities and homeowners into a high-risk status. The low-density class had greatest risk of fire exposure, but the medium-density class contained a greater concentration of houses. Classification of the wildland–urban interface or intermix based on realized fire occurrences provides an objective foundation for identifying residential densities at risk of fire exposure, which permits disclosure of risk, prioritization of resources to communities and homeowners with greater wildfire exposure, development of strategies for communities to coexist with fire, and responses to reduce vulnerability.