Mapping the world’s intact forest landscapes by remote sensing

Protection of large natural forest landscapes is a highly important task to help fulfill different international strategic initiatives to protect forest biodiversity, to reduce carbon emissions from deforestation and forest degradation, and to stimulate sustainable forest management practices. This paper introduces a new approach for mapping large intact forest landscapes (IFL), defined as an unbroken expanse of natural ecosystems within areas of current forest extent, without signs of significant human activity, and having an area of at least 500 km2. A global IFL map was created using..

Remote Sensing of Savannas and Woodlands

Savannas and woodlands are one of the most challenging targets for remote sensing. This book provides a current snapshot of the geographical focus and application of the latest sensors and sensor combinations in savannas and woodlands. It includes feature articles on terrestrial laser scanning and on the application of remote sensing to characterization of vegetation dynamics in the Mato Grosso, Cerrado and Caatinga of Brazil. It also contains studies focussed on savannas in Europe, North America, Africa and Australia. It should be important reading for environmental practitioners and scientists globally who are concerned with the sustainability of the global savanna and woodland biome

An introduction to the Australian and New Zealand flux tower network - OzFlux

Published: 31 October 2016OzFlux is the regional Australian and New Zealand flux tower network that aims to provide a continental-scale national research facility to monitor and assess trends, and improve predictions, of Australia's terrestrial biosphere and climate. This paper describes the evolution, design, and current status of OzFlux as well as provides an overview of data processing. We analyse measurements from all sites within the Australian portion of the OzFlux network and two sites from New Zealand. The response of the Australian biomes to climate was largely consistent with global studies except that Australian systems had a lower ecosystem water-use efficiency. Australian semi-arid/arid ecosystems are important because of their huge extent (70 %) and they have evolved with common moisture limitations. We also found that Australian ecosystems had a similar radiation-use efficiency per unit leaf area compared to global values that indicates a convergence toward a similar biochemical efficiency. The two New Zealand sites represented extremes in productivity for a moist temperate climate zone, with the grazed dairy farm site having the highest GPP of any OzFlux site (2620 gC m⁻² yr⁻¹) and the natural raised peat bog site having a very low GPP (820 gC m⁻² yr⁻¹). The paper discusses the utility of the flux data and the synergies between flux, remote sensing, and modelling. Lastly, the paper looks ahead at the future direction of the network and concludes that there has been a substantial contribution by OzFlux, and considerable opportunities remain to further advance our understanding of ecosystem response to disturbances, including drought, fire, land-use and land-cover change, land management, and climate change, which are relevant both nationally and internationally. It is suggested that a synergistic approach is required to address all of the spatial, ecological, human, and cultural challenges of managing the delicately balanced ecosystems in Australasia.Jason Beringer ... Wayne Meyer ... et al

An introduction to the Australian and New Zealand flux tower network - OzFlux

© Author(s) 2016. OzFlux is the regional Australian and New Zealand flux tower network that aims to provide a continental-scale national research facility to monitor and assess trends, and improve predictions, of Australia's terrestrial biosphere and climate. This paper describes the evolution, design, and current status of OzFlux as well as provides an overview of data processing. We analyse measurements from all sites within the Australian portion of the OzFlux network and two sites from New Zealand. The response of the Australian biomes to climate was largely consistent with global studies except that Australian systems had a lower ecosystem water-use efficiency. Australian semi-arid/arid ecosystems are important because of their huge extent (70 %) and they have evolved with common moisture limitations. We also found that Australian ecosystems had a similar radiation-use efficiency per unit leaf area compared to global values that indicates a convergence toward a similar biochemical efficiency. The two New Zealand sites represented extremes in productivity for a moist temperate climate zone, with the grazed dairy farm site having the highest GPP of any OzFlux site (2620 gC m-2 yr-1) and the natural raised peat bog site having a very low GPP (820 gC m-2 yr-1). The paper discusses the utility of the flux data and the synergies between flux, remote sensing, and modelling. Lastly, the paper looks ahead at the future direction of the network and concludes that there has been a substantial contribution by OzFlux, and considerable opportunities remain to further advance our understanding of ecosystem response to disturbances, including drought, fire, land-use and land-cover change, land management, and climate change, which are relevant both nationally and internationally. It is suggested that a synergistic approach is required to address all of the spatial, ecological, human, and cultural challenges of managing the delicately balanced ecosystems in Australasia

Decreasing net primary production due to drought and slight decreases in solar radiation in China from 2000 to 2012

Terrestrial ecosystems have continued to provide the critical service of slowing the atmospheric CO2 growth rate. Terrestrial net primary productivity (NPP) is thought to be a major contributing factor to this trend. Yet our ability to estimate NPP at the regional scale remains limited due to large uncertainties in the response of NPP to multiple interacting climate factors and uncertainties in the driver data sets needed to estimate NPP. In this study, we introduced an improved NPP algorithm that used local driver data sets and parameters in China. We found that bias decreased by 30% for gross primary production (GPP) and 17% for NPP compared with the widely used global GPP and NPP products, respectively. From 2000 to 2012, a pixel-level analysis of our improved NPP for the region of China showed an overall decreasing NPP trend of 4.65 Tg C a−1. Reductions in NPP were largest for the southern forests of China (−5.38 Tg C a−1), whereas minor increases in NPP were found for North China (0.65 Tg C a−1). Surprisingly, reductions in NPP were largely due to decreases in solar radiation (82%), rather than the more commonly expected effects of drought (18%). This was because for southern China, the interannual variability of NPP was more sensitive to solar radiation (R2 in 0.29–0.59) relative to precipitation (R2 \u3c 0.13). These findings update our previous knowledge of carbon uptake responses to climate change in terrestrial ecosystems of China and highlight the importance of shortwave radiation in driving vegetation productivity for the region, especially for tropical forests

Fire as a Fundamental Ecological Process: Research Advances and Frontiers

Fire is a powerful ecological and evolutionary force that regulates organismal traits, population sizes, species interactions, community composition, carbon and nutrient cycling and ecosystem function. It also presents a rapidly growing societal challenge, due to both increasingly destructive wildfires and fire exclusion in fire‐dependent ecosystems. As an ecological process, fire integrates complex feedbacks among biological, social and geophysical processes, requiring coordination across several fields and scales of study. Here, we describe the diversity of ways in which fire operates as a fundamental ecological and evolutionary process on Earth. We explore research priorities in six categories of fire ecology: (a) characteristics of fire regimes, (b) changing fire regimes, (c) fire effects on above‐ground ecology, (d) fire effects on below‐ground ecology, (e) fire behaviour and (f) fire ecology modelling. We identify three emergent themes: the need to study fire across temporal scales, to assess the mechanisms underlying a variety of ecological feedbacks involving fire and to improve representation of fire in a range of modelling contexts. Synthesis: As fire regimes and our relationships with fire continue to change, prioritizing these research areas will facilitate understanding of the ecological causes and consequences of future fires and rethinking fire management alternatives

Vegetation Phenology as a Function of Plant Functional Type and Urbanization

Urban land cover contributes to higher temperatures in urban areas compared to adjacent rural areas, which can cause an earlier start of the growing season for urban vegetation. Variations in plant community characteristics between urban and rural areas also produce intra-urban differences in vegetation phenophases, although few studies have investigated differences in phenology between plant functional types in multiple urban environments. In this study I used an exploratory analysis based on the Landsat Phenology Algorithm and weather station data to quantify differences in leaf-onset dates for different plant functional types in the New York City Metropolitan Area. The results demonstrate that Landsat can be used to identify urban-rural variations in leaf-onset for different plant functional types, and that these variations are driven by different climate variables depending on plant functional type. Furthermore, results from such analyses suggest that long-term changes in leaf onset vary across different plant functional types—i.e., grasslands may be advancing at a different rate than forests

Incidencia del fuego en un gradiente altitudinal de las sierras del centro de la Argentina

En los ecosistemas de montaña, la distribución de la vegetación a lo largo del gradiente altitudinal fue tradicionalmente interpretada en términos de la temperatura decreciente desde la base hacia arriba; pero los fuegos pueden co-variar con el gradiente de altitud, también cumpliendo un papel importante. En las montañas del centro de la Argentina (500-2800 m s. n. m.), los fuegos son uno de los disturbios principales y pueden cumplir una función importante en modular la dinámica de la vegetación a lo largo de la altitud. Sin embargo, hasta ahora ningún estudio describió la incidencia del fuego a lo largo del gradiente altitudinal. Nosotros comparamos la incidencia del fuego entre cinco intervalos altitudinales usando una base de datos de fuegos espacialmente explícita, de 18 años, derivada de sensores remotos. Para cada intervalo, descartamos las áreas no combustibles y calculamos para cada año la incidencia del fuego como el porcentaje de área quemada. La incidencia de fuego mostró un patrón unimodal a lo largo del gradiente de altitud. Las incidencias más altas se registraron a altitudes intermedias, en los intervalos de 1301-1700 m y 901-1300 m, con 3.2% y 2.7% de incidencia anual, respectivamente. La incidencia de fuego más baja se registró en el intervalo inferior (500-900 m), con 1.3% quemado anualmente, en promedio. La mayor incidencia del fuego observada a altitudes intermedias es consistente con un aumento importante de la cobertura de pastizales por encima de los 900 m s. n. m., con una simultánea reducción en la extensión de bosques. Hacia mayores altitudes, la menor incidencia del fuego es consistente con la presencia de barreras impuestas por la topografía y por las áreas rocosas no combustibles, y con las condiciones más húmedas. La mayor incidencia de fuegos observada a altitudes intermedias puede estar limitando la expansión de bosques en dichas áreas. A mayores altitudes, la baja cobertura arbórea podría estar explicada por una combinación de fuegos y presión ganadera. Nuestro estudio es el primero que muestra cómo varía la incidencia del fuego a lo largo del gradiente completo de altitud, brindando una herramienta importante para entender la distribución de la vegetación y planificar estrategias de conservación y restauración.In mountain ecosystems, vegetation distribution along elevation has been traditionally interpreted in terms of the decreasing temperature from base to top, but wildfires may co-vary with the elevation gradient, also playing an important role. In the mountains of central Argentina (500-2800 m a. s. l.) wildfires are one of the main disturbances, which may have an important role in shaping vegetation dynamics along elevation. However, to date, no study described the fire pattern along the elevation gradient. We compared fire incidence among five elevation intervals using an 18-year spatially explicit fire database derived from remote sensing. For each interval, we discarded unburnable areas and calculated fire incidence per year as the percentage of burned area. Fire incidence showed a hump-shaped pattern along the elevation gradient. The highest fire incidence occurred at intermediate elevations, in the 1301-1700 m and 901-1300 m intervals, with averages of 3.2 and 2.7% of the area being burned annually, respectively. The lowest fire incidence occurred at the lowest interval (500-900 m), with 1.3% being burned annually on average. The greater fire incidence observed at intermediate elevations is consistent with a sharp increase in the cover of grasslands above 900 m a. s. l., with an associated reduction in forest occupation. Towards higher elevations, the lower fire incidence is consistent with the presence of topographic breaks, greater proportion of unburnable surfaces that work as firebreaks and moister conditions. The greater fire incidence observed at intermediate elevations may be limiting forest expansion in those areas. At higher elevations the low forest cover may be explained by a combination of fire and livestock pressure. Our study is the first to show how fire incidence varies along the complete elevation gradient, bringing an important tool to understand vegetation distribution and plan future conservation and restoration strategies.Fil: Argañaraz, Juan Pablo. Comisión Nacional de Actividades Espaciales. Instituto de Altos Estudios Espaciales "Mario Gulich"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Cingolani, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Bellis, Laura Marisa. Comisión Nacional de Actividades Espaciales. Instituto de Altos Estudios Espaciales "Mario Gulich"; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecológica. Cátedra de Ecología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Giorgis, Melisa Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Fire as a fundamental ecological process: Research advances and frontiers

Fire is a powerful ecological and evolutionary force that regulates organismal traits, population sizes, species interactions, community composition, carbon and nutrient cycling and ecosystem function. It also presents a rapidly growing societal challenge, due to both increasingly destructive wildfires and fire exclusion in fire‐dependent ecosystems. As an ecological process, fire integrates complex feedbacks among biological, social and geophysical processes, requiring coordination across several fields and scales of study. Here, we describe the diversity of ways in which fire operates as a fundamental ecological and evolutionary process on Earth. We explore research priorities in six categories of fire ecology: (a) characteristics of fire regimes, (b) changing fire regimes, (c) fire effects on above‐ground ecology, (d) fire effects on below‐ground ecology, (e) fire behaviour and (f) fire ecology modelling. We identify three emergent themes: the need to study fire across temporal scales, to assess the mechanisms underlying a variety of ecological feedbacks involving fire and to improve representation of fire in a range of modelling contexts. Synthesis : As fire regimes and our relationships with fire continue to change, prioritizing these research areas will facilitate understanding of the ecological causes and consequences of future fires and rethinking fire management alternatives

Land use change in the high mountain belts of the central Apennines led to marked changes of the grassland mosaic

Aims High mountain pastures are hotspots of biodiversity, but grazing cessation and climate change are causing tall-grass encroachment and expansion of scrublands and forests. As part of biodiversity conservation efforts, grassland variation needs to be investigated at different spatial scales. We aimed to assess the landscape mosaic variation that occurred between 1988 and 2015 in the higher Mediterranean mountains. We investigated the recovery or land-degradation processes related to land use change, the effects of site condition, the impacts on grassland mosaic heterogeneity, and the threats to biodiversity. Location Sibillini Mountains (central Italy), over 1,650 m a.s.l. Methods We used two-step object-based supervised classification on Landsat 5 and 8 satellite images to analyze changes in landscape patterns and vegetation cover on formerly low-intensity pastures, by assessing the Normalized Difference Vegetation Index variation between 1988 and 2015. Twenty percent of the polygons obtained from segmentation were visually interpreted and assigned to five land cover classes. We generated a land use transition matrix and used Fourier Transforms to detect trends in variation of landscape mosaics and fragmentation. Results We observed prominent dynamics of the grassland mosaic leading to the homogenization of its structure through decreasing patch heterogeneity, especially on south-facing slopes. Grasslands shifted from open communities to dense pastures, with a reduction of scree and spread of tall grasses. The former trend could be understood as a recovery process reverting screes to conditions in equilibrium with local landform and climatic features, while the invasion of tall grasses is a land-degradation process that might lead to local species extinction and loss of habitat connectivity. Conclusions Pronounced changes in the large-scale landscape characteristics, mainly due to land use changes, of which scientists and managers of protected areas are not fully aware, are underway in the top mountain sectors of the study area