Reduced Vegetation Cover Research Articles

Wildlife Corridors and Regional Biodiversity Conservation around Selected Wildlife Protected Areas in Uganda

Wildlife corridors play a vital role in regional biodiversity conservation. Ecological attributes, changes in corridors and wildlife populations, threats to wildlife corridor functionality were evaluated using a case study of the eight wildlife protected areas in Uganda. A survey was conducted from September 2017 to May 2019, using document review, interviews, the Nature Conservancy’s Conservation Action Planning methodology, and Geographical Information System/remote sensing. The findings revealed a total of 20 key wildlife corridors in the landscape with key ecological attributes that augment regional biodiversity conservation. These corridors experience reducing vegetation cover, degradation, loss of connectivity, and degraded stepping stone habitats. They (corridors) are threatened by illegal activities, poaching and illegal wildlife tracking, unsustainable natural resource use, human population pressure, habitat transition/changes, wild fires, trans-boundary threats, infrastructure development, and climate change which affect habitat quality, diversity, and continuity. Despite the existing changes and threats, the elephant population, a migratory animal population increased. The wildlife corridors are important in conservation of regional biological diversity through maintaining the nativeness, pristineness, diversity, and resilience or adaptability of the ecosystems. The policy makers, wildlife managers, local authorities and other conservation bodies and practitioners should develop plans, policies or strategies to sustainably manage and conserve migratory animal biodiversity. Further research should be conducted to establish the functional connectivity of wildlife corridors including trends in their width across the landscape and come up with corridor restoration options. Keywords: Biodiversity, Connectivity, Landscape, Protected areas, Threats, Wildlife DOI: 10.7176/JRDM/87-05 Publication date: September 30 th 2022

Age- and Sex-Specific Association Between Vegetation Cover and Mental Health Disorders: Bayesian Spatial Study.

BackgroundDespite growing evidence that reduced vegetation cover could be a putative risk factor for mental health disorders, the age- and the sex-specific association between vegetation and mental health disorder cases in urban areas is poorly understood. However, with rapid urbanization across the globe, there is an urgent need to study this association and understand the potential impact of vegetation loss on the mental well-being of urban residents.ObjectiveThis study aims to analyze the spatial association between vegetation cover and the age- and sex-stratified mental health disorder cases in the neighborhoods of Toronto, Canada.MethodsWe used remote sensing to detect urban vegetation and Bayesian spatial hierarchical modeling to analyze the relationship between vegetation cover and mental health disorder cases. Specifically, an Enhanced Vegetation Index was used to detect urban vegetation, and Bayesian Poisson lognormal models were implemented to study the association between vegetation and mental health disorder cases of males and females in the 0-19, 20-44, 45-64, and ≥65 years age groups, after controlling for marginalization and unmeasured (latent) spatial and nonspatial covariates at the neighborhood level.ResultsThe results suggest that even after adjusting for marginalization, there were significant age- and sex-specific effects of vegetation on the prevalence of mental health disorders in Toronto. Mental health disorders were negatively associated with the vegetation cover for males aged 0-19 years (−7.009; 95% CI −13.130 to −0.980) and for both males (−4.544; 95% CI −8.224 to −0.895) and females (−3.513; 95% CI −6.289 to −0.681) aged 20-44 years. However, for older adults in the 45-64 and ≥65 years age groups, only the marginalization covariates were significantly associated with mental health disorder cases. In addition, a substantial influence of the unmeasured (latent) and spatially structured covariates was detected in each model (relative contributions>0.7), suggesting that the variations in area-specific relative risk were mainly spatial in nature.ConclusionsAs significant and negative associations between vegetation and mental health disorder cases were found for young males and females, investments in urban greenery can help reduce the future burden of mental health disorders in Canada. The findings highlight the urgent need to understand the age-sex dynamics of the interaction between surrounding vegetation and urban dwellers and its subsequent impact on mental well-being.

Green Sahara tipping points in transient climate model simulations of the Holocene

The ‘Greening’ and subsequent desertification of the Sahara during the early to mid-Holocene is a dramatic example of natural climate change. We analyse a suite of simulations with a newly palaeo-conditioned configuration of the HadCM3 coupled model that is able to capture an abrupt desertification of North Africa during this time. We find that this model crosses a threshold of moisture availability for vegetation at around 6000 years before present. The resultant rapid reduction in vegetation cover acts to reduce precipitation through moisture recycling and surface albedo feedbacks. Precursor drying events which are not directly forced also indicate that the model is close to a critical moisture level. Similar precursor-like events appear in a Holocene record from the East of the continent, hinting that the natural system may resemble some of the properties of this model simulation. The overall response is not fundamentally altered by the inclusion of solar irradiance variations or volcanic eruptions. The simulated timing of the abrupt transition is mostly controlled by orbital forcing and local positive feedbacks, but it is also modulated to some extent by the state of the atmosphere and ocean. Comparisons with proxy records across North Africa show good agreement with the model simulations, although the simulations remain overly dry in the East. Overall, a threshold response may present a useful model of the real transition, but more high-resolution palaeoclimate records would help to discriminate among the predictions of climate models.

Spatiotemporal evolution of desertification based on integrated remote sensing indices in Duolun County, Inner Mongolia

Desertification causes not only a reduction of vegetation cover and surface moisture but also the expansion of sandy land. Considering that the modified soil adjusted vegetation index (MSAVI) is linearly related to canopy cover, albedo plays a significant role in the surface energy balance, and the sandy feature index (SFI) can identify sandy land. This paper proposed a desertification monitoring index (DMI) based on MSAVI, albedo and SFI to accurately monitor desertification. In addition, three classification methods (quantile grading, the susceptibility index segmentation method, and Jenks Natural Breaks) were used to divide the DMI into non-desertification, mild desertification, moderate desertification, and severe desertification. The relative exponential entropy model was adopted to select the optimal method for desertification classification. Spatiotemporal distributions of desertification in Duolun County were finally observed from 2005 to 2020. The results show that (1) although MSAVI, albedo and SFI have their own advantages in monitoring desertification, a single indicator is not suitable for various land uses. The DMI can combine the advantages of MSAVI, albedo and SFI in desertification monitoring and is more consistent with the real desertification levels. (2) Compared with quantile grading and susceptibility index segmentation methods, Jenks Natural Breaks has the smallest relative exponential entropy (2.124), with an overall classification accuracy of 88.21%, indicating that Jenks Natural Breaks is an optimal method for desertification monitoring. (3) Although approximately 1708.60 km2 of desertification areas have improved from 2005 to 2020, accounting for 44.23% of the whole area, the remaining areas are still under fluctuating or degraded conditions. This shows that the local government has made some progress in desertification protection, but the areas under fluctuating or degraded conditions still require protection or management.

Potential drivers of common brushtail possum (

Australia’s terrestrial mammalian fauna have experienced severe declines since European settlement. On the Murray–Darling floodplain in south-eastern Australia, common brushtail possums (Trichosurus vulpecula, ‘possums’), have contracted to riparian zones. Although an important possum refuge, little is known about possum population dynamics here. We examined possum population dynamics and potential drivers across two decades on the Murray River floodplain at Calperum Station. We related possum density to satellite derived fractional cover, (a measure of the proportion of green, non-green and bare ground cover), and contextualised these findings using tree condition and grazing pressure datasets. Possum surveys were conducted between 1998 and 2019 in riparian and non-riparian habitats and density was modelled in relation to fractional cover values of green, non-green, and bare ground. Possum density fluctuated between 1998 and 2008 but in 2018 and 2019, possums were undetectable. Possum density was negatively associated with bare ground and positively associated with non-green. Overgrazing by kangaroos likely reduced vegetation cover and diversity and contributed to possum decline, via a reduction in possum food resources and increased exposure to predation. Inconsistent monitoring meant that the population decline was not detected until after it had occurred, and management interventions were not triggered, highlighting the dilemma of allocating scarce monitoring resources.

Time Series of Remote Sensing Data for Interaction Analysis of the Vegetation Coverage and Dust Activity in the Middle East

Motivated by the lack of research on land cover and dust activity in the Middle East, this study seeks to increase the understanding of the sensitivity of dust centers to climatic and surface conditions in this specific region. In this regard, we explore vegetation cover and dust emission interactions using 16-day long-term Normalized Difference Vegetation Index (NDVI) data and daily Aerosol Optical Depth (AOD) data from Moderate Resolution Imaging Spectroradiometer (MODIS) and conduct spatiotemporal and statistical analyses. Eight major dust hotspots were identified based on long-term AOD data (2000–2019). Despite the relatively uniform climate conditions prevailing throughout the region during the study period, there is considerable spatial variability in interannual relationships between AOD and NDVI. Three subsets of periods (2000–2006, 2007–2013, 2014–2019) were examined to assess periodic spatiotemporal changes. In the second period (2007–2013), AOD increased significantly (6% to 32%) across the studied hotspots, simultaneously with a decrease in NDVI (−0.9% to −14.3%) except in Yemen−Oman. Interannual changes over 20 years showed a strong relationship between reduced vegetation cover and increased dust intensity. The correlation between NDVI and AOD (−0.63) for the cumulative region confirms the significant effect of vegetation canopy on annual dust fluctuations. According to the results, changes in vegetation cover have an essential role in dust storm fluctuations. Therefore, this factor must be regarded along with wind speed and other climate factors in Middle East dust hotspots related to research and management efforts.

Amphibian diversity in urban and peri-urban landscapes of Benin City, a Southern Nigerian City in the rainforest biotope

Benin City, the capital of Edo State of Nigeria has undergone tremendous changes in recent times, especially with the aggressive rate of urbanisation in the last two decades. This has invariably resulted in habitat loss and fragmentation for the amphibian community of the city and its environs. In order to determine the effect of urbanization on the amphibian diversity of the area, a survey was undertaken between July 2009 and July 2010 using Visual and Acoustic Encounter Survey method. Higher species diversity and richness was observed from the peri-urban compared to the urban areas. However, the abundance of amphibian in the urban zone was significantly higher than that of the peri-urban zone (p<0.05). Hyperolius concolor phases A and C, H. sylvaticus, Afrixalus nigeriensis and A. vittiger were restricted to the peri-urban area while Ptychadena pumilio and Sclerophrys maculata occurred more in the urban areas. The most dominant species was S. maculata (26.6%) while the least dominant species was A. vittiger (0.22%). Peri-urban areas contributed 53% while the urban zone contributed 47% to total abundance. More tree frogs were collected from the peri-urban than the urban sites, which could be due to the reduced vegetation cover in the latter. However, the paucity of tree frogs in the urban zone did not have any significant impact on the taxa differences between the two zones. The abundance of P. pumilio and P. mascareniensis, which are typical savanna frogs is an indication of the degraded nature of the study area. The low records of A. poecilonotus, A. vittiger and H. concolor phase A and the complete absence of forest-dependent species could be due to their inability to tolerate human influence on the environment. There is need for balance in the use of land resources for urbanization and amphibian conservation.

Identification of temporary livestock enclosures in Kenya from multi-temporal PlanetScope imagery

The use of night-time livestock enclosures, often referred to as “bomas”, “corrals”, or “kraals”, is a common practice across African rangelands. Bomas protect livestock from predation by wildlife and potential theft. Due to the concentration of animal faeces inside bomas, they not only become nutrient-rich patches that can add to biodiversity, but also hotspots for the emission of nitrous oxide (N2O), an important greenhouse gas, especially when animals are kept inside for long periods. To provide an accurate estimate of such emissions for wider landscapes, bomas need to be accounted for. Moreover, initial experiments indicated that more frequent shifts in the boma locations could help to reduce N2O emissions. This stresses the need for better understanding where bomas are located, their numbers, as well as when they are actively used. Given the recent advances in satellite technology, resulting in high-frequent spectral measurements at fine spatial resolution, solutions to address these needs are now within reach. This study is a first effort to map and monitor the appearance of bomas with the use of satellite image time series. Our main dataset was a dense times series of 3 m resolution PlanetScope multispectral imagery. In addition, a reference dataset of boma and non-boma locations was created using GPS-collar tracking data and 0.5 m resolution Pléiades imagery. The reduction of vegetation cover and increase of organic material following boma installation result in typical spectral changes when contrasted against its surroundings. Based on these spectral changes we devised an empirical approach to infer approximate boma installation dates from PlanetScope's near infrared (NIR) band and used our reference dataset for setting optimal parameter values. A NIR spatial difference index resulted in clear temporal patterns, which were more apparent during the wet season. At landscape scale our approach reveals clear spatio-temporal patterns of boma installation, which could not be revealed from less frequent sub-meter resolution imagery alone. While further improvements are possible, we show that small-sized (150–500 m2) temporary surface changes, such as those that occur when pastoralists use mobile bomas, can be detected with dense image time series like those offered by the PlanetScope constellation. In future, this could lead to better assessment of a) spatio-temporal livestock distribution, b) the contribution of bomas to N2O emissions and soil fertility at landscape scale, and c) the uptake of enclosure rotation practices at large spatial scales.

Erosion resistance of vegetation-covered soils: Impact of different grazing conditions in salt marshes and analysis of soil-vegetation interactions by the novel DiCoastar method

The analysis of soil-vegetation interactions in erosion processes along coastlines requires accurate information about various factors influencing the upper soil layer. Yet, some of these parameters were previously determined by simplified, often hand held devices, and these were often biased by the skill and experience of the operator. This study thus investigates the erosion resistance of salt marsh soils influenced by grazing conditions for providing crucial findings for policy making and land management decisions; to that end, we present and use a novel shear resistance measuring device. This measuring device, called DiCoastar, was developed with a controllable step-motor and now allows us for the first time the determination of time histories of shear resistance by repeatable in-situ measurements, gaining information about the interaction between soil and root systems. A field study was conducted in salt marshes at Cäciliengroden and at Sönke-Nissen-Koog, both foreland salt marshes at the German North Sea coast. The two sites had been chosen due to their difference in grazing intensities, featuring semi-natural/ungrazed, moderately grazed and intensively grazed salt marshes. This was to enable the investigation of influences on soil shear strength and vegetation cover. Measurements of shear resistance were conducted with the DiCoastar in the chosen sites in the vicinity of the dike toes; it is found that the new device now provides consistent and repeatable measurements, irrespective of the operator, and only based on the pre-set control parameters. Results of the field study demonstrate that a marked increase of shear strength is only found in sites with high intensity grazing, but this is accompanied by a strong reduction in the vegetation cover and plant diversity, especially with regard to the vertical density distribution of the vegetation cover. As the reduction in vegetation cover leads to reduced wave attenuation over salt marshes and increased flow velocities, an increased shear stress on the soil surface, which potentially exceeds the increased shear strength, is expected. Based on this, the results obtained lead to the assumption that an increase in the erosion potential of these foreland marshes by high grazing pressure is more likely as well as a reduction in dike stability.

Effect of Decreasing the Interception of Solar Illuminance by Vegetation on Ground Temperature in Degraded Grasslands

Reduced vegetation cover caused by grassland degradation results in the interception of solar illuminance significantly decreasing, then leading to an increase in ground temperature, which has a significant impact on biological growth and regional climate. Based on the field experiment, we explore the interception of solar illuminance by grasslands with three degrees of degradation and its effect on the soil temperature. Solar illuminance at various heights and times was measured to obtain the interception by vegetation, which included reduction by physical shielding and consumption by the plants’ life activities. Solar illuminance in the subareas sprayed with herbicide was merely reduced by physical shielding, and the difference in solar illuminance interception between normally growing grasslands and fatal grasslands was used for the plants’ life activities. This method described above was almost the first to be used for the exploration of the functional allocation of solar illuminance interception. The percentage of solar illuminance interception was largest in the non-degraded grassland (80–95% at different times), including a 50–60% reduction on account of physical shielding and a 20–45% consumption by the grass’s life activities. Light interception by grassland vegetation directly reduced the grassland temperature. The increment of ground temperature reaches 4–13 °C when a non-degraded grassland turns into a severely degraded grassland.

Context‐dependent effects of shifting large herbivore assemblages on plant structure and diversity

Abstract Despite wide recognition of the importance of anthropogenically driven changes in large herbivore communities—including both declines in wildlife and increases in livestock—there remain large gaps in our knowledge about the impacts of these changes on plant communities, particularly when combined with concurrent changes in climate. Considering these prominent forms of global change in tandem enables us to better understand controls on savanna vegetation structure and diversity under real‐world conditions. We conducted a field experiment using complete and semi‐permeable herbivore exclosures to explore the difference in plant communities among sites with wild herbivores only, with cattle in addition to wild herbivores, and with no large herbivores. To understand variation in effects across climatic contexts, the experiment was replicated at three locations along a topoclimatic gradient in California. Critically, this is the first such experiment to compare cattle and wildlife impacts along an environmental gradient within a single controlled experiment. Vegetation structure responded strongly to herbivore treatment regardless of climate. Relative to the isolated effects of wildlife, exclusion of all large herbivores generally increased structural components related to cover and above‐ground biomass while the addition of cattle led to reductions in vegetation cover, litter, shading and standing biomass. Furthermore, wildlife had a consistent neutral or positive effect on plant diversity, while the effect of livestock addition was context dependent. Cattle had a neutral to strongly negative effect at low aridity, but a positive effect at high aridity. These results suggest that (a) herbivore effects can override climate effects on vegetation structure, (b) cattle addition can drive different effects on diversity and (c) herbivore effects on diversity are modulated by climate. Synthesis. Our results illustrate very distinctive shifts in plant communities between two realistic forms of change in ungulate herbivore assemblages—livestock addition and large herbivore losses—particularly for plant diversity responses, and that these responses vary across climatic contexts. This finding has important implications for the management and protection of plant biodiversity given that over a quarter of the Earth's land area is managed for livestock and climate regimes are changing globally.

A Remote Sensing Approach for Displaying the Changes in the Vegetation Cover at Az Zakhnuniyah Island at Arabian Gulf, Saudi Arabia.

In the terrestrial ecosystem, vegetation is the important component of exchanging of water and energy in biogeochemical and climate cycle. A study was conducted to detect the vegetation cover change at Az Zakhnuniyah island by using remote sensing techniques. It includes vegetation analysis using normalized difference vegetation index (NDVI) while comparing with climatological data including temperature, humidity, and precipitation. A clear trend was seen in climatological parameters where temperature and humidity were rising decade by decade although NDVI did not show. In addition, increasing soil salinization over the years was observed when soil salinity index was used. NDVI-based long-term decadal analysis on vegetation cover based on Landsat surface reflectance data showed increase of vegetation cover which was also linked to precipitation trends. Also, the short-term demi-decadal comparison using PROBA-V showed the vegetation cover reduction between 2015 and 2019. Nevertheless, the sea level surrounding the island also showed an increasing trend of 0.34 cm/y, which could be the cause of inundation in some parts of the island in future. Furthermore, all these trends need to be observed in entirety as many of those trends can be interlinked.

Stage-Specific Environmental Correlates of Reproductive Success in Boreal Toads (Anaxyrus boreas boreas)

Compensatory recruitment can facilitate the persistence of populations experiencing high adult mortality. Because early life-stages of many taxa, including amphibians, are difficult to mark and recapture, sources of variation in survival at these stages often are unknown, which creates barriers to improving in situ recruitment rates. We leveraged count data and open N-mixture models to examine the environmental factors associated with the hatching of egg clutches, tadpole survival, and probability of metamorphosis in Boreal Toads (Anaxyrus boreas boreas) that inhabit pastures leased for cattle grazing in western Wyoming, USA. We conducted weekly surveys and measured a suite of environmental variables at 20 breeding ponds during May–September 2018. The hatching of egg clutches was most strongly related to pond surface area, as clutches often desiccated at smaller ponds. Weekly tadpole survival was lowest in ponds with high abundance of aquatic predators. Predation did not preclude metamorphosis, which was more strongly associated with higher dissolved oxygen and vegetation cover. Cattle grazing reduced vegetation cover in and around breeding ponds, which resulted in lower levels of dissolved oxygen. Grazing-induced habitat changes are therefore likely to negatively influence tadpole metamorphosis both via indirect effects on dissolved oxygen, and direct effects on vegetation cover, which also serves as feeding sites and escape cover from predators. We demonstrate the success of three critical phases in early life-stage development (egg hatching, tadpole survival, metamorphosis) was associated with different environmental factors. The inclusion of stage-specific responses in demographic analyses is therefore critical for a thorough understanding of what limits populations.

Drought as a driver of vegetation change in Succulent Karoo rangelands, South Africa

We document changes in rangeland during a prolonged drought in the arid Karoo. Rangeland in this arid region is species-rich and dominated by a mixture of long-lived succulent and non-succulent shrubs. Ranching has led to the domination of vegetation by less palatable species, and resting does little to restore diversity because most species are long-lived. Between 2015 and 2020, a combination of rising temperatures and low rainfall reduced vegetation cover and grazing potential throughout the Karoo. Mortality varied among species, habitat and with predrought rangeland condition, but appeared independent of size class. Growth form was not a good predictor of drought survival, although vegetation dominated by non-succulent shrub species before the drought was dominated by a succulent shrub species toward the end of the drought. Dieback was greater on deep soil than in drainage lines and on stony rises. Historically degraded landscapes lost relatively more vegetation cover and grazing capacity than areas protected from grazing. By reducing dominant, long-lived, non-forage shrub species, drought appears to be changing the composition of the vegetation to a state that may have higher grazing potential, particularly if livestock numbers are reduced and reseeding is carried out during the recovery period.

Vegetation, hydrology, and sand movement interactions on the Slate Canyon alluvial fan-Keeler Dunes Complex, Owens Valley, California

Relationships among hydrology, sand movement, and vegetation community dynamics within the Slate Canyon alluvial fan and Keeler Dunes Complex, Owens (dry) Lake, California, were characterized. Construction of flood control berms (1954, 1967) cut off surface overflow events on the alluvial fan, resulting in subsequent very low plant cover and significant sand movement. Hydrologic modeling and analysis of plant cover and sand movement from aerial photos were combined to document and explain changes in plant cover in the study area for upland vegetation and groundwater-dependent vegetation. Where hydrologic factors dominated, upland vegetation was observed to have much lower cover (median 6%) than groundwater-dependent vegetation (median 41%) and much higher variability throughout the 1944 to 2012 study period. For upland vegetation, simulated potential plant cover was 9.2% and this declined to 4.4% when channel flow inputs were eliminated due to berm construction. Areas with minimal sand movement over the study period expressed actual plant cover similar to simulated levels. Areas with significant sand movement, however, had much lower plant cover than simulated potential values and areas with flood flow inputs had much higher cover. The decline in plant cover from 9.2 to 4.4% resulted in an estimated 4.4-fold greater sand movement (normalized sand flux increased from 14% to 62% relative to 100% for bare soil). The sensitivity of surface stability at low vegetation cover and the potential for hydrologic changes to reduce vegetation cover in this range illustrates how hydrology and sand movement interactions can destabilize sensitive sand dunes.

Seasonal variation in the vertical distribution of birds in the dry deciduous forest of central western Madagascar

The annual patterns of precipitation in the dry deciduous forest of Madagascar are characterized by a dry season when the majority of trees lose their leaves and a wet season with full foliage development. Such variation allows the examination in shifts in the vertical distribution of birds and to their response to changing environmental conditions. Patterns of birds in the dry deciduous forest of Kirindy CNFEREF, central western Madagascar, were analyzed related to the vertical variation of vegetation structure and microclimate during 2 study periods: the dry (24 Aug to 16 Sep 2017) and wet seasons (25 Jan to 17 Feb 2018). Six line transects in forest habitat of 1,000 m each were used to survey birds, and each was associated with linear sampling to quantify vegetation structure. Data loggers were employed to record temperature and relative humidity across the vertical strata. During the dry season, associated with the microclimate aridity and reduction in vegetation cover in the upper strata, the number of species and individual birds found on the ground increased. During the wet season, fewer birds occurred on the ground, and abundance and species richness increased in the canopy. These results show the sensitivity of birds with regard to environmental fluctuations. However, regardless of the season, birds frequented mainly the mid-story, which had the highest abundance of species as compared to upper and lower vertical strata.

A Long-term Spatial and Temporal Analysis of NDVI Changes in Java Island Using Google Earth Engine

Java is Indonesia’s and the world’s most populous island. The increase in population on the island of Java reduces the area of forest and other vegetation covers. Landslides, floods, and other natural disasters are caused by reduced vegetation cover. Furthermore, it has the potential to lead to the extinction of flora and fauna. The Normalized Difference Vegetation Index (NDVI) can be used to monitor the vegetation cover. This study analyzes the NDVI changes value from 2005 to 2020 using Terra and Aqua MODIS image data processed using Google Earth Engine. Processing was carried out in some stages: down-setting, performing NDVI processing, calculating monthly average NDVI, calculating annual average NDVI, and analyzing. From the study results, the NDVI value of Terra and Aqua MODIS data has a solid but imperfect correlation coefficient due to differences in orbital time which causes differences in solar zenith angle, sensor viewing angle, and azimuth angle. Then from this study, it was found that overall, changes in vegetation density cover on the island of Java decreased, which was indicated by the NDVI decline rate of -0.00047/year. The most significant decrease in NDVI value occurred in the period 2015–2016, covering an area of 13994.630 km2, and the most significant increase in NDVI occurred in the period 2010–2011, covering an area of 2256.101 km2.

Impact of vegetation cover loss on surface temperature and carbon emission in a fastest-growing city, Cumilla, Bangladesh

Human pressures, combined with changing hydrology and land resources, have a distinct effect on the carbon chain and ecosystem resilience. The increase in urban areas contributes significantly to the loss of vegetation cover (VC), which accelerates carbon emissions, increasing land surface temperature (LST) and global warming. This study used remote sensing and GIS techniques to estimate the Land Use/Land Cover (LU/LC) changes by focusing on VC loss and its impact on LST and carbon emissions over Cumilla during 1994–2019. The study's findings confirmed an alarming reduction of VC by 6.65% from 1994 to 2009 with around 20% increase of urban area, contributing LST rise from 23 °C to 31 °C. The trends were continuous, with a decrease in VC loss by 1.75% during 2009–2019, contributing 28 °C–36 °C LST rise in the study area. The results also confirmed a significant positive correlation between VC loss and LST. Results indicate that the massive amount of carbon attracted the sun's rays due to the VC loss and raising the surface temperature by 11.2 °C (1.86 °C/year) since 1994, which directly contributing to global warming. Thus, to mitigate climate hazards, efforts to slow urbanization to reduce pollution gateways and increase carbon sinks through afforestation will significantly contribute to protecting humanity from global warming.

Effects of livestock and wildlife grazing intensity on soil carbon dioxide flux in the savanna grassland of Kenya

Although grazing is the primary land use in the savanna lowland of southern Kenya, the effects of grazing on soil carbon dioxide flux (RS) remain unclear. A 12-month study was conducted from January to December 2020 on the effects of six grazing intensities sites (overgrazed (OG), heavily grazed (HG), moderately grazed (MG), moderately to lightly grazed (M-LG), lightly grazed (LG) and no grazing (NG)) on RS on. A camera trap was used to monitor the total number of animals at each site, indicating the grazing intensity. Weekly measurements of RS were taken using static greenhouse gas chambers along with simultaneous measurements of soil temperature (TS) and volumetric soil water content (WS) (depth of 5 cm). Mean RS at HG, MG, M-LG and LG sites was approximately 15–25% higher than at NG and OG sites (p < 0.001). Mean WS increased with decrease in grazing especially in the dry season, while TS increased with increase in grazing. We observed bimodal temporal variation in RS and WS due to two wet seasons in the year. Thus, variation in RS across the study period followed the changes in WS rather than those in TS. Mean values of RS in the wet seasons were significantly higher (>45%) than those in the dry seasons, and WS accounted for 71% of the temporal variability in RS (p < 0.05). In addition, the enhanced vegetation index (EVI, interpreted as a proxy for vegetation cover) explained 60% of the variance of RS, and WS and EVI together explained 75%. EVI showed a negative relationship (p < 0.05) with animal intensity, indicating that more grazing reduced vegetation cover and, consequently, soil organic carbon and biomass. Soil bulk density was lower at less grazed sites. While RS variability was unaffected by total nitrogen content, pH, and texture, correspondence analysis demonstrated that the main factors influencing RS dynamics across the year under different grazing intensities were WS and vegetation cover. Our results contribute to closing the existing knowledge gap regarding the effects of grazing intensity on RS in East Africa savannas. Therefore, this information is of great importance in understanding carbon cycling in savanna grassland, as well as the identification of the potential consequences of increasing land pressure caused by rising livestock numbers, and will assist in the development of climate-smart livestock management in East Africa.

The Identification and Classification of Arid Zones through Multicriteria Evaluation and Geographic Information Systems—Case Study: Arid Regions of Northwest Mexico

Arid and semiarid regions are geographic units that cover approximately 43% of the earth’s surface worldwide, and conditions of extreme drought and reduced vegetation cover predominate in these regions. In Mexico, arid and semiarid ecosystems cover more than half of the territory, with desertification, mainly caused by anthropogenic activities and climatic events, as the main problem in these regions. The present research aimed to assess, identify, and classify arid and semiarid zones by employing a methodology based on multicriteria evaluation analysis (MCA) using the weighted linear combination (WLC) technique and geographic information systems (GIS) in the hydrological administrative regions (HARs) of the North Pacific, Northwest, and Baja California Peninsula, located in Northwest Mexico. Data related to aridity, desertification, degradation, and drought were investigated, and the main factors involved in the aridity process, such as surface temperature, soil humidity, precipitation, slopes, orientations, the normalized difference vegetation index (NDVI), and evapotranspiration, were obtained. For the standardization of factors, a fuzzy inference system was used. The weight of each factor was then determined with the analytical hierarchy process (AHP). To delimit arid regions, the classification of arid zones proposed by the United Nations Environment Program (UNEP) was used, and the result was an aridity suitability map. To validate the results, the sensitivity analysis method was applied. Quantitative and geospatial aridity indicators were obtained at the administrative hydrological level and by state. The main results indicated that semiarid and dry subhumid zones predominated, representing 40% and 43% of the surface of the study area, respectively, while arid regions represented 17%, and humid regions represented less than 1%. In addition, of the states for which 100% of the surface lay in the study area, it was observed that Baja California and Baja California Sur had the largest arid and semiarid zones, while subhumid regions predominated in Sonora and Sinaloa.