Cropland Cover Research Articles

What Environmental Factors Influence the Concentration of Fecal Indicator Bacteria in Groundwater? Insights from Explanatory Modeling in Uganda and Bangladesh.

Information about microbial water quality is critical for managing water safety and protecting public health. In low-income countries, monitoring all drinking water supplies is impractical because financial resources and capacity are insufficient. Data sets derived from satellite imagery, census, and hydrological models provide an opportunity to examine relationships between a suite of environmental risk factors and microbial water quality over large geographical scales. We investigated the relationships between groundwater fecal contamination and different environmental parameters in Uganda and Bangladesh. In Uganda, groundwater contamination was associated with high population density (p < 0.001; OR = 1.27), high cropland coverage (p < 0.001; OR = 1.47), high average monthly precipitation (p < 0.001; OR = 1.14), and high surface runoff (p < 0.001; OR = 1.37), while low groundwater contamination was more likely in areas further from cities (p < 0.001; OR = 0.66) and with higher forest coverage (p < 0.001; OR = 0.70). In Bangladesh, contamination was associated with higher weekly precipitation (p < 0.001; OR = 1.44) and higher livestock density (p = 0.05; OR = 1.11), while low contamination was associated with low forest coverage (p < 0.001; OR = 1.23) and high cropland coverage (p < 0.001; OR = 0.80). We developed a groundwater contamination index for each country to help decision-makers identify areas where groundwater is most prone to fecal contamination and prioritize monitoring activities. Our approach demonstrates how to harness satellite-derived data to guide water safety management.

Reconstruction of cropland cover using historical literature and settlement relics in farming areas of Shangjing Dao during the Liao Dynasty, China, around 1100 AD

To improve the accuracy of historical cropland data, we reconstructed cropland cover in the northern China’s farming–pastoral zone during the Liao dynasty using historical literature and settlement relics. We first reconstructed the total cropland area using historical household data based on the cropland area per household. Next, we allocated the cropland area into 5′ grid cells weighted by settlement density to generate a cropland data. Our main findings were as follows: (1) Data on settlement relics enabled not only the identification of ancient farming areas but also the allocation of cropland cover within high resolution grids in the study area. (2) In the flourishing period of the Liao dynasty, the total cropland area was 0.39 × 104 km2. The cropland grids comprised 28.30% of the total grids, with average and maximum values of cropland fractions of 6.61% and 31.18%, respectively. (3) Compared with our result, we found that the PJ overestimate the cropland area of the study area in 1100 AD, whereas the HYDE 3.2 underestimate it. The area of anthropogenic land use in KK 10 was larger than the cropland area in this study too. None of the three global datasets revealed the mosaic spatial distribution pattern of cropland cover in this study area. (4) The orders of land suitability for cultivation during the Liao dynasty and the present period were almost the identical, even in the farming–pastoral zone of northern China, which has fragile ecological environment.

An assessment of remote sensing-based drought index over different land cover types in southern Africa

ABSTRACT An understanding of drought and land cover interaction plays a crucial role in vegetation vulnerability studies and land use planning. However, there is paucity of information on drought, land cover and land use interaction in southern Africa. We analysed the drought impact on land cover using Globcover land cover data and Vegetation Condition Index (VCI) for the 2015 to 2016 season. The 2015 to 2016 season was chosen because it was the worst drought in southern Africa since the 1980s. We developed a novel land cover ‘social pixels’ or ‘village pixels’ which represents rural communities. The Kruskal–Wallis test was used to evaluate whether there is a significant difference in drought impact among the land cover classes. The response of each land cover to drought impact was calculated by correlating Standardized Precipitation Evapotranspiration Index (SPEI) and Normalized Difference Vegetation Index (NDVI). Our results reveal that the evergreen forests and the flooded vegetation were the most severely affected by the 2015–2016 drought. However, the lowest VCI values were recorded within the village pixels land cover, indicating the vulnerability of rural communities to drought impacts. The vegetation response to drought impact ranged from 2 months (crops) to 8 months (flooded vegetation). With regards to drought recurrence (1998 to 2018), the crop and grassland land cover recorded the highest drought frequency whilst the forest had the least drought frequency.

Changing Land use Pattern in the Raniganj Coal Belt and Its Sustainable Management: A Case Study of Mangalpur Opencast Colliery

Opencast coal mining has an immense impact on the changing land use and land cover pattern of any colliery belt. This is the main thrust of the present study. Land-use practices, like built-up area, cropland, vegetation, water body, bare land, mining area etc. have been identified. The pattern of changing land use and land cover in the Mangalpur private opencast colliery has been analysed. At the same time, entire Raniganj block has been studied with the help of secondary data. SOI Topographic map 73M/2 has been used to show the situation of collieries both underground and opencast of Raniganj block in 1967. The land use and land cover changes in the Raniganj block have been analysed for 12 years i.e., from the year 2007 to 2019 using remote sensing techniques. The changes have been detected at 6 year time gap. For that purpose Landsat-5 TM, Landsat-8 OLI/ TIRS satellite images are used. Apart from that, the quantification of spatio-temporal dynamics of land use and land cover patterns are also examined by supervised image classification. The study exposed that extend of the mining area and the bare land area has increased in 2019 compared to 2007. On the contrary, cropland and vegetation cover have decreased significantly during the period under study. To achieve sustainable use of land in the study area, some management procedures have been discussed at the end

Changes in forest landscape patterns resulting from recent afforestation in Europe (1990–2012): defragmentation of pre-existing forest versus new patch proliferation

Recent afforestation in Europe might involve deep changes on landscape composition and configuration. We show that afforestation promotes defragmentation of pre-existing forests and new patch proliferation, in forest-dominated and non-forest-dominated landscapes respectively, while it is not associated to decreasing landscape diversity. These processes are modulated by geographic factors and might affect functional connectivity and biodiversity conservation in newly forested landscapes. A recent forest increase in Europe might drive changes in the landscape pattern, with increasing forest defragmentation and connectivity but decreasing land cover diversity that, in turn, might affect biodiversity conservation. However, little is known about these patterns of change and their association with the environmental context. To explore the association of forest cover increase with changes in the spatial pattern of European landscapes, while considering their original landscape composition, geographical position and elevation. We obtained data from ESA and GFC land cover maps and other GIS layers and performed a set of GLM on randomly selected 752 landscapes with recent (1990–2012) forest increase. A decrease in landscape diversity in the last decades was not associated to forest increase but to high cropland and low scrub-grassland cover. A forest increase promoted the defragmentation of already-existing forests and new patch proliferation in forest-dominated and non-dominated landscapes, respectively. These processes also depend on elevation and geographical position, with forest defragmentation concentrated in Northern and Eastern Europe and new patch proliferation in southern and western regions, and in mid-elevation areas. Changes in afforested landscapes are more complex than expected and cannot be solely attributable to forest increase, but also to landscape composition and location across elevation and geographical gradients across Europe.

Nutrition management in conversion-to-organic citrus orchard in the Indonesian citrus and subtropical fruits research institute

One of the main challenges in organic citrus cultivation is how to manage land and nutrients so that plant needs can be met all the time while maintaining soil quality. This paper provides information on applied nutrition management, evaluation of changes in soil characters, and production in the conversion-to-organic citrus orchard in the Indonesian Citrus and Subtropical Fruits Research Institute. The citrus used are 5-year-old Siam citrus (Citrus nobilis Lour.) grafted on Japansche Citroen rootstock. The initial stage in the conversion to organic farming is the creation of ecosystems that support organic agriculture and improvement of soil fertility through the cultivation of gliricidia (Gliricidia sepium) and marigold (Tagetes erecta L.) as living hedges around the garden, planting citronella grass (Cymbopogon nardus) and marigold (Tagetes erecta L.) in the embankment, and planting land cover crop. Nutrition management in the orchard includes the application of green manure sourced from biomass of the living hedges, soybeans (Glycine max (L.) Merill) and wild plants obtained from the orchard; application of compost from dolomite enriched goat manure; and application of liquid organic fertilizer from fermented goat manure with local microorganisms. Nutrition management applied in the organic conversion orchard in the first year was followed by improvement in some soil characters, namely pH, organic matter content, cation exchange capacity, total N and exchangeable Ca but vice versa for available P, exchangeable K, and Mg. Citrus production in the first year fell by about 11% from the previous year and was followed by a decrease in the other quality parameters of fruits, except for the levels of vitamin C and total acid.

Methodology for credibility assessment of historical global LUCC datasets

Land use-induced land cover change (LUCC) is an important anthropogenic driving force of global change that has influenced, and is still influencing, many aspects of regional and global environments. Accurate historical global land use/cover datasets are essential for a better understanding of the impacts of LUCC on global change. However, there are not only evident inconsistencies in current historical global land use/cover datasets, but inaccuracies in the data in these global dataset revealed by historical record-based reconstructed regional data throughout the world. A focus in historical LUCC and global change research relates to how the accuracy of historical global land cover datasets can be improved. A methodology for assessing the credibility of existing historical global land cover datasets that addresses temporal as well as spatial changes in the amount and distribution of land cover is therefore needed. Theoretically, the credibility of a global land cover dataset could be assessed by comparing similarities or differences in the data according to actual land cover data (the “true value”). However, it is extremely difficult to obtain historical evidence for assessing the credibility of historical global land cover datasets, which cannot be verified through field sampling like contemporary global land cover datasets. We proposed a methodological framework for assessing the credibility of global land cover datasets. Considering the types and characteristics of the available evidence used for assessments, we outlined four methodological approaches: (1) accuracy assessment based on regional quantitative reconstructed land cover data, (2) rationality assessment based on regional historical facts, (3) rationality assessment based on expertise, and (4) likelihood assessment based on the consistency of multiple datasets. These methods were illustrated through five case studies of credibility assessments of historical cropland cover data. This framework can also be applied in assessments of other land cover types, such as forest and grassland.

An enhanced spatiotemporal fusion method – Implications for coal fire monitoring using satellite imagery

Many real-world applications require remotely sensed images at both high spatial and temporal resolutions. This requirement, however, is generally not met by single satellite system. A number of spatiotemporal fusion models have been developed to overcome this constraint. Landsat and Visible Infrared Imaging Radiometer Suite (VIIRS) data have been extensively used for detection and monitoring of active fires at different scales. Fusing the data obtained from these sensors will, therefore, significantly contribute to the satellite-based monitoring of fires. Among the available spatiotemporal fusion methods, the spatial and temporal adaptive reflectance fusion model (STARFM) and enhanced STARFM (ESTARFM) algorithms have been widely used for studying the land surface dynamics in the homogeneous and heterogeneous regions. The present study explores the applicability of STARFM and ESTARFM algorithms for fusing the high spatial resolution Landsat-8 OLI data with high temporal resolution VIIRS data in the context of active surface coal fire monitoring. Further, a modified version of ESTARFM algorithm, referred as modified-ESTARFM, is developed to improve the performance of the fusion model. Jharia coalfield (India), known for widespread occurrences of coal fires, is taken as the study area. The qualitative and quantitative assessments of the predicted (synthetic) Landsat-like images from different algorithms (STARFM, modified-STARFM, ESTARFM, modified-ESTARFM) indicate that the modified-ESTARFM outperforms the other fusion approaches used in this study. Considering the advantages, limitations and performance of the algorithms used, modified-ESTARFM along with STARFM can be used for surface coal fire monitoring. The study will not only contribute to remote sensing based coal fire studies but also to other applications, such as forest fires, crop residue burning, land cover and land use change, vegetation phenology, etc.

Exposure of Foraging Bees (Hymenoptera) to Neonicotinoids in the U.S. Southern High Plains.

Exposure to pesticides is a major threat to insect pollinators, potentially leading to negative effects that could compromise pollination services and biodiversity. The objectives of this study were to quantify neonicotinoid concentrations among different bee genera and to examine differences attributable to body size and surrounding land use. During the period of cotton planting (May-June), 282 wild bees were collected from habitat patches associated with cropland, grassland, and urban land cover and analyzed for three neonicotinoids (thiamethoxam, clothianidin, and imidacloprid). Twenty bees among eight genera contained one or more of the neonicotinoid compounds and detections occurred in all landscape types, yet with the most detections occurring in cropland-associated habitats. Apis Linnaeus (Hymenoptera: Apidae), Melissodes Latreille (Apidae), Perdita Smith (Andrenidae), and Lasioglossum Curtis (Halictidae) had multiple individuals with neonicotinoid detections. Two of the largest bees (Apis and Melissodes) had the greatest number of detections within genera, yet the relatively small-bodied genus Perdita had the three highest neonicotinoid concentrations reported. The number of detections within a genus and average generic body mass showed a marginally significant trend towards larger bees having a greater frequency of neonicotinoid detections. Overall, the relatively low percentage of detections across taxa suggests practices aimed at conserving grassland remnants in intensified agricultural regions could assist in mitigating exposure of wild bees to agrochemicals, while differences in bee traits and resource use could in part drive exposure. Further work is needed to address variable agrochemical exposures among pollinators, to support strategies for conservation and habitat restoration in affected landscapes.

Spatiotemporal patterns of water use efficiency in China and responses to multi-scale drought

Drought is a natural disaster that profoundly affects the carbon and water cycles in terrestrial ecosystems. Quantifying the responses of terrestrial carbon and water cycles to drought is crucial for assessing the impacts of climate variability on these ecosystems. Using Moderate Resolution Imaging Spectroradiometer gross primary productivity (GPP) and evapotranspiration (ET) products, this study evaluated the spatiotemporal patterns and trends of water use efficiency (WUE) for China’s terrestrial ecosystems from 2000 to 2014 and analyzed their responses to multi-scale drought across different river basins, vegetation types, and climatic zones. The key findings are as follows: (1) The annual WUE in China’s vegetated areas has significantly increased at a linear rate of 0.01/gC kg−1 H2O a−1 (P < 0.05). (2) The spatial patterns of average annual WUE in China’s vegetated areas had large spatial variability. Higher average annual WUE values were found in the basins with high forest or cropland coverage and within humid climatic zones. Lower average annual WUE values were found in the basins with high grassland coverage and within arid and semi-arid climate zones. In total, 40.59% of the WUE in China’s vegetated areas significantly increased (P < 0.05). They were mainly distributed in Northern China. (3) From 2000 to 2014, WUE values in 32.79%, 7.21%, 23.33%, and 8.57% of the China’s vegetated areas were highly sensitive to drought in the growing season, spring, summer, and autumn, respectively. (4) The growing season, summer, and autumn had significantly higher correlations (P < 0.05) over the Standardized Precipitation and Evapotranspiration Index-24 time scale than those over the other time scales. (5) During the growing season, WUE values in river basins with a humid climate and forest coverage were more sensitive to drought than to other river basins.

Geostatistical mapping and quantitative source apportionment of potentially toxic elements in top- and sub-soils: A case of suburban area in Beijing, China

Abstract The risk assessment and source identification for potentially toxic elements (PTEs) in soils, particularly agricultural soils from megacities, are significant for environmental protection and pollution control. In this study, an intensive sampling (4127 topsoil samples and 994 subsoil samples) was conducted in the Shunyi District, Beijing, which is a suburban area with extensive cropland cover and has been impacted by the megacity over several decades. Concentrations and distributions of 8 PTEs, including V, Cr, Ni, As, Cd, Zn, Pb and Hg, were determined, and their possible sources were quantitatively assessed by principal component analysis (PCA), redundancy analysis (RDA), positive matrix factorization (PMF) analysis, and anthropogenic contribution ratio method. Among 8 PTEs, Zn, V and Cr exhibited significantly high concentrations in soils, with means of 68.29, 68.19 and 52.13 mg/kg, respectively, followed by Pb (23.84 mg/kg), Ni (22.91 mg/kg), As (8.30 mg/kg), Cd (0.15 mg/kg) and Hg (0.05 mg/kg). RDA and PCA demonstrated that the rock weathering was a significant source of V, Cr, Ni and As, and the local emissions and atmospheric deposition respectively contributed most of Cd, Zn and Pb, and of Hg in soils. This source category was confirmed the spatial variations of anthropogenic contribution ratios to individual PTEs. PMF results showed that the local emissions contributed 96.3% of Cd, 44.4% of Zn and 32.0% of Pb in soils, and the atmospheric source carrying urban pollutants amounted to 78.7–80.2% of Hg. In this case, several effective analysis methods have been successfully applied to quantify the impact of a megacity to PTEs in suburban soils. These results improve understanding of the contamination status of PTEs in suburban soils from Beijing megacity, and provide basis for policymaker regarding environmental protection and pollution control.

Ecosystem service valuation of a natural reserve region for sustainable management of natural resources

Abstract The mangrove ecosystem is extremely important for providing essential ecosystem services, which are crucial for subsistence and human well-being. Using time-series satellite data products and different unit values, the spatially explicit Ecosystem Service Value (ESV) of six eco-regions of the Sundarbans Biosphere Reserve (SBR), India, has been calculated for four reference years, viz. 1973, 1988, 2002 and 2013. The maximum ESV (million US$ year1) is provided by the mangrove forest (2292–44468), followed by water surface (65–4244), cropland (26–3938), and sparse vegetation cover (0–326). The total ESV (million US$ year1) of Sundarbans is estimated to be 16629.5, 20175.7, 19733.4, and 16761.3 for 1973, 1988, 2002, and 2013 respectively. The regulation of gas and climate, raw material production, and cultural ecosystem services are entirely dependent on the mangrove ecosystem, while the waste treatment, cultural, and water regulation services are found to be highly sensitive to the changes in water bodies. The food production and biodiversity services exhibiting higher sensitivity to the changes in cropland, water regulation and soil formation and retention services show higher sensitivity to the changes in mixed vegetation cover. The current study has thoroughly evaluated the sensitivity and response behavior of six ecoregions of Sundarbans. The outcome of this study will enable the decision-makers, planners, as well as researchers to adopt necessary action plans for strengthening and protecting the natural resources of this biosphere reserve.

Beyond deforestation: Land cover transitions in Mexico

Conversion of land cover is one of the main causes of global environmental change and identifying the regions where sustained trends of land change are occurring provides useful information for land and resources management. For all ecoregions in Mexico, we analyzed land use changes over 14 years (2001–2014) using MODIS images (250m) and identified regions that had significant gains or loss of woody vegetation, pasturelands, or croplands. The land use patterns varied greatly among the 40 major ecoregions, but in general, woody vegetation and cropland cover increased while pastures decreased. In contrast to previous studies, much of the increase in croplands did not correspond with hotspots of decline in pastures but occurred in the Sonora and Chihuahuan deserts ecoregions in northern Mexico. Industrial cotton, sorghum, and pecans production for export where the major crops responsible for the increase in these ecoregions. Similar to patterns in the rest of Latin America, pasture expansion mainly occurred in ecoregions in the tropical moist forest biome (e.g. Veracruz and Peten-Veracruz ecoregions). The ecoregions that experienced the greatest increase in woody vegetation were the Balsas dry forest ecoregion along the Pacific coast and Trans Mexican volcanic oak-pine ecoregion. In both regions, rural-urban migration appears to be an important driver of the transition from grasslands to woody vegetation, while the conversion of croplands to woody vegetation in the Tamaulipan mezquital ecoregion was clearly associated with drug related violence. This study documents how the complex interactions among national and international demand for agricultural products, national policies, demography, violence and climate change are affecting land change across Mexico.

Tree Cover in the Surrounding Landscape Reduces Burrowing Owl (Athene cunicularia) Occupancy of Black-Tailed Prairie Dog Colonies in South Dakota

Burrowing Owl (Athene cunicularia) population declines have led to the owl's designation as a species of conservation concern in South Dakota. Burrowing Owls nest primarily in black-tailed prairie dog (Cynomys ludovicianus) colonies, but a significant proportion of colonies in South Dakota are not occupied by owls. We studied the influence of landscape-level habitat variables on colony selection by Burrowing Owls. We used call-playback surveys to document presence or absence of Burrowing Owls at 613 prairie dog colonies throughout western and central South Dakota. We used a geographic information system to calculate the percent cover of prairie dog colonies, grassland, cropland, and tree canopy in the surrounding landscape at four buffer sizes. We modeled Burrowing Owl occupancy of prairie dog colonies using logistic regression, and ranked models using Akaike's Information Criterion. All competitive models contained a tree-canopy-cover variable. Increasing tree canopy cover within 800 m and 1200 m of colony centers was associated with decreasing likelihood of occupancy by Burrowing Owls. Grassland, cropland, and prairie dog colony cover variables did not influence occupancy by Burrowing Owls, and these variables did not improve model fit or discrimination. In landscapes where the presence of nesting burrows is not a limiting factor, as in central and western South Dakota, Burrowing Owls occupied colonies based on the absence of trees. Trees provide habitat for avian and mammalian predators and reduce the available foraging area for Burrowing Owls around prairie dog colonies. Management for Burrowing Owls should include conserving prairie dog colonies in landscapes with few trees and preventing the establishment of trees near occupied colonies.

PENGARUH PERBEDAAN HABITAT KELAPA SAWIT (Elaeis guineensis Jacq.) TERHADAP KELIMPAHAN MUSUH ALAMI ULAT API (LEPIDOPTERA : PSYCHIDAE)

One of the important pests attacking coconut palm is Ulat Pemakan Daun Kelapa Sawit (UPDKS) like the Caterpillar. The management of habitat can be done with clean cultivation practices or cultivation use nuts cover soil (cover crop) to increase natural enemies. The research was carried out in April until July 2017. The purpose of this study was to know the abundance of natural enemies population Caterpillar fire contained in research. The location of the research consists of a private plantation with a cover crop and land communities without a cover crop. Observations of the Caterpillar's fire done every week, from first week to third week. The observation is done by swiping pitfall trap method and net. Each block palm oil taken 5 plot used to sweep net and each plot placed 2 pitfall trap. The abundance of natural enemies population level Caterpillar fires on plantation with a cover crop of 137 individuals. The community's land without a cover crop of 107 individuals. Natural enemies was found in the predator type of land cover crop as much as 88% and natural enemies of type parasitoid as much as 12%. Predator type natural enemies present on the land without a cover crop as much as 99% and parasitoid type of natural enemies as much as 1%. Keywords: caterpillar, natural enemies, palm oil, parasitoid, predator

Antagonistic, synergistic and direct effects of land use and climate on Prairie wetland ecosystems: Ghosts of the past or present?

AbstractAimWetland loss and degradation threaten biodiversity to an extent greater than most ecosystems. Science‐supported responses require understanding of interacting effects of land use and climate change on wetland biodiversity.LocationAlberta, Canada.MethodsWe evaluated how current climate, climate change (as a ghost of the past), land use and wetland water quality relate to aquatic macroinvertebrates and birds.ResultsClimatic relationships and climate–land use interactions were observed on chironomid abundance, but not macroinvertebrate taxa richness (MTR) or odonate abundance, which responded to land use and water chemistry. Chironomid abundance was positively associated with cropland and negatively associated with total precipitation. Higher cropland cover and dissolved organic carbon synergistically interacted with total precipitation to affect chironomids. MTR was negatively related to salinity, yet greater area of non‐woody riparian vegetation attenuated salinity effects on MTR. Odonate abundance was negatively related to total phosphorus. Higher grassland cover also increased the negative relationship of total phosphorous to odonate abundance. Climatic relationships and climate–land use interactions were observed on bird species richness (BSR) and abundance of several bird functional groups. Higher BSR and abundances of several bird groups were positively related to average rainfall and greater warming temperatures over time. Area of non‐crop cover and wetlands was positively associated with most bird groups and BSR. Warming temperatures over time ameliorated the negative relationship of higher cropland or less shrubland on aerial insectivores and other bird groups.Main conclusionsClimate patterns and climate change are as important as land use pressures with stronger impacts on birds. Climate change was more influential than current climate and provided novel empirical evidence that progressively warmer, wetter conditions is benefiting some bird groups, including aerial insectivores, a group of conservation concern. Riparian vegetation ameliorated the negative impacts of climate and water quality gradients on MTR and could mitigate global change impacts in agricultural systems.

Historical records reveal the distinctive associations of human disturbance and extreme climate change with local extinction of mammals

Accelerated anthropogenic impacts and climatic changes are widely considered to be responsible for unprecedented species extinction. However, determining their effects on extinction is challenging owing to the lack of long-term data with high spatial and temporal resolution. In this study, using historical occurrence records of 11 medium- to large-sized mammal species or groups of species in China from 905 BC to AD 2006, we quantified the distinctive associations of anthropogenic stressors (represented by cropland coverage and human population density) and climatic stressors (represented by air temperature) with the local extinction of these mammals. We found that both intensified human disturbances and extreme climate change were associated with the increased local extinction of the study mammals. In the cold phase (the premodern period of China), climate cooling was positively associated with increased local extinction, while in the warm phase (the modern period) global warming was associated with increased local extinction. Interactive effects between human disturbance and temperature change with the local extinction of elephants, rhinos, pandas, and water deer were found. Large-sized mammals, such as elephants, rhinos, and pandas, showed earlier and larger population declines than small-sized ones. The local extinction sensitivities of these mammals to the human population density and standardized temperature were estimated during 1700 to 2000. The quantitative evidence for anthropogenic and climatic associations with mammalian extinction provided insights into the driving processes of species extinction, which has important implications for biodiversity conservation under accelerating global changes.

Testing the native invasion hypothesis to explain anthropogenic influence on stream fish assemblages

In communities or regions where non-native fish species still do not predominate, changes in the assemblage composition are driven by loss, gain or substitution by native species only. We investigated the native invasion hypothesis in small streams, in which human modifications may influence fish assemblage composition by boosting the expansion and establishment of widespread species, as well as of species commonly found in large streams and rivers. Fish community data from 54 lowland streams from South Brazil were used to investigate this hypothesis. We found a positive relationship between cropland cover at the catchment scale and the dominance of fish species that commonly inhabit large streams or rivers (inferred on museum records). We also observed a weak and negative relationship between site elevation and the percentage of widely distributed species in fish assemblages. Our results partly support the hypothesis of native invasion in lowland streams, but the low explanatory power of the models suggests that it is less pronounced compared to highland streams. Our results contribute to understand inconsistencies among studies on the effects of land use on stream fish assemblages using traditional metrics (alpha and beta diversities). For instance, land use can initially increase fish species richness in small streams by favouring the occurrence and establishment of fish species common to rivers. In this sense, alternative metrics that consider specific changes in native species distribution, such as proliferation of common species, should be used to better assess the mechanisms that drive changes in communities of aquatic ecosystems.

Socio-economic predictors of environmental performance among African nations

Socio-economic changes in Africa have increased pressure on the continent’s ecosystems. Most research investigating environmental change has focused on the changing status of specific species or communities and protected areas, but has largely neglected the broad-scale socio-economic conditions underlying environmental degradation. We tested national-scale hypotheses regarding the socio-economic predictors of ecosystem change and degradation across Africa, hypothesizing that human density and economic development increase the likelihood of cumulative environmental damage. Our combined environmental performance rank includes national ecological footprint, proportional species threat, recent deforestation, freshwater removal, livestock density, cropland coverage, and per capita emissions. Countries like Central African Republic, Botswana, Namibia, and Congo have the best relative environmental performance overall. Structural equation models indicate that increasing population density and overall economic activity (per capita gross domestic product corrected for purchasing-power parity) are the most strongly correlated with greater environmental degradation, while greater wealth inequality (Gini index) correlates with better environmental performance. This represents the first Africa-scale assessment of the socio-economic correlates of environmental degradation, and suggests that dedicated family planning to reduce population growth, and economic development that limits agricultural expansion (cf. intensification) are needed to support environmental sustainability.

A comparison of remotely-sensed and inventory datasets for burned area in Mediterranean Europe

Quantitative estimate of observational uncertainty is an essential ingredient to correctly interpret changes in climatic and environmental variables such as wildfires. In this work we compare four state-of-the-art satellite fire products with the gridded, ground-based EFFIS dataset for Mediterranean Europe and analyse their statistical differences. The data are compared for spatial and temporal similarities at different aggregations to identify a spatial scale at which most of the observations provide equivalent results. The results of the analysis indicate that the datasets show high temporal correlation with each other (0.5/0.6) when aggregating the data at resolution of at least 1.0° or at NUTS3 level. However, burned area estimates vary widely between datasets. Filtering out satellite fires located on urban and crop land cover classes greatly improves the agreement with EFFIS data. Finally, in spite of the differences found in the area estimates, the spatial pattern is similar for all the datasets, with spatial correlation increasing as the resolution decreases. Also, the general reasonable agreement between satellite products builds confidence in using these datasets and in particular the most-recent developed dataset, FireCCI51, shows the best agreement with EFFIS overall. As a result, the main conclusion of the study is that users should carefully consider the limitations of the satellite fire estimates currently available, as their uncertainties cannot be neglected in the overall uncertainty estimate/cascade that should accompany global or regional change studies and that removing fires on human-dominated land areas is key to analyze forest fires estimation from satellite products.