Marion Stellmes

• Dr.
• Senior Researcher at Freie Universität Berlin

The country of Spain is representative of land change processes in Mediterranean member states of the European Union (EU). These land change processes are often triggered by European, national and sub-national policies and include widespread land abandonment and urbanisation trends, as well as an increase in land use intensities accompanied by stro...

The repopulation of abandoned areas in Angola after 27years of civil war led to a fast and extensive expansion of agricultural fields to meet the rising food demand. Yet, the increase in crop production at the expense of natural resources carries an inherent potential for conflicts since the demand for timber and wood extraction are also supposed t...

The analysis and evaluation of ecosystems in the Okavango region must include a thorough analysis of the fire regime. This requires a full understanding of its components such as fire frequency, fire season and fire intensity. For the Okavango region these components were derived based on an extensive multi-scale compilation of the MODIS products “...

We developed a large-area preprocessing framework for multisensor Landsat data, capable of processing large data volumes. Cloud and cloud shadow detection is performed by a modified Fmask code. Surface reflectance is inferred from Tanré's formulation of the radiative transfer, including adjacency effect correction. A precompiled MODIS water vapor d...

There have been increasing calls in gentrification studies to examine the geography of gentrification in slums, as little is known about the patterns and processes of slum gentrification, especially in sub-Saharan African cities where slums house over 50% of the urban population. This study explored the spatiotemporal changes in slums in Lagos, Nig...

The prediction of conflicts is performed, if at all, on large spatial and temporal scales. They rely on national and often incomplete databases, especially regarding sub-Saharan Africa. However, since conflicts become more and more a matter of intrastate violence, conflict related information on regional level can improve the identification of vuln...

Background This paper presents an analysis of fire regimes in the poorly studied Angolan catchment of the Okavango Delta in Botswana. We used MODIS data to examine the frequency and seasonality of fires over 20 years (from 2000 to 2020) in three dominant vegetation types (miombo woodlands, open woodlands and grasslands, and short closed to open bus...

We present a framework for mapping grazing management units in extensive pastoral landscapes. Mapping such units from remote sensing, particularly in the pastoral landscapes of East Africa, is usually hampered by high cost of field data collection and by the fact that the relationship between rangeland ecological characteristics and rangeland use f...

Aim Tropical old-growth grasslands are increasingly acknowledged as biodiverse ecosystems, but they are understudied in many aspects. Geoxyle species are a key component in many of these ecosystems, their belowground storage organs and bud banks are functionally diverse and contribute to the grasslands’ resilience. However, the drivers of the geoxy...

Drylands range across more than half of the global terrestrial area and harbour about a quarter of continental vertebrate species, many of them endemic. However, this fauna is being increasingly threatened, in particular the one that inhabits deserts, one of the last biomes on earth. This work tracks the most relevant global change drivers acting o...

Different slums exhibit different levels of resilience against the threat of eviction. However, little is known about the role of the social capital of the slum community in this context. This study investigates the factors contributing to slum resilience in the Lagos Metropolis, Nigeria, through a social capital lens. This study first investigates...

Many studies analyzing spaceborne hyperspectral images (HSIs) have so far struggled to deal with a lack of pure pixels due to complex mixtures of urban surface materials. Recently, an alternative concept of gradients in urban surface material composition has been proposed and successfully applied to map cities with spaceborne HSIs without the requi...

Mapping heathland habitats is generally challenging due to fine-scale habitats as well as spectral ambiguities between different classes. A multi-seasonal time-series of multispectral RapidEye data from several phenological stages was analysed towards the classification of different vegetation communities. A 3-level hierarchical dependent classific...

Within the Miombo belt the tri-national Okavango Basin is one of the last remaining intact river basins in Africa. It supports highly diverse social-ecological systems with the majority of the population strongly depending on the direct provision of multiple ecosystem services. Following independence and peace treaties the region is now rapidly bei...

Analysis Ready Data (ARD) have undergone the most relevant pre-processing steps to satisfy most user demands. The freely available software FORCE (Framework for Operational Radiometric Correction for Environmental monitoring) is capable of generating Landsat ARD. An essential step of generating ARD is atmospheric correction, which requires water va...

Atmospheric correction is a crucial preprocessing step for the analysis of optical satellite imagery like Landsat. Among the radiance-modifying gases, atmospheric water vapor is spatially and temporally variable, and cannot be measured reliably from the Landsat sensors. As such, atmospheric correction of Landsat data requires spatially and temporal...

Earth observation derived land surface phenology (LSP) provides important information on status and dynamics of land cover. Commonly, LSP metrics are derived from coarse resolution sensors due to their high temporal repetition rate. The coarse spatial resolution is often not sufficient of tracking land cover and its change in spatially heterogeneou...

The spatial extension of the countries covered by SASSCAL, the diversity of their landscapes, and the range of social and ecological processes, constitute a challenge to environmental research. The latter have sometimes needed to focus on small test sites for very specific questions, or else required data and methods that allowed large area assessm...

Dry tropical forests are facing large-scale conversion and degradation processes and are the most endangered forest type worldwide. We analyse these processes in the dry tropical forest type of miombo woodlands in a rural area of south-central Angola. We show that large-scale conversion to agricultural areas takes place in this area, as does modifi...

Dry tropical forests undergo massive conversion and degradation processes. This also holds true for the extensive Miombo forests that cover large parts of Southern Africa. While the largest proportional area can be found in Angola, the country still struggles with food shortages, insufficient medical and educational supplies, as well as the ongoing...

Societal, economic and scientific interests in knowing where biodiversity is, how it is faring and what can be done to efficiently mitigate further biodiversity loss and the associated loss of ecosystem services are at an all-time high. So far, however, biodiversity monitoring has primarily focused on structural and compositional features of ecosys...

Tropical dry forests provide globally important ecosystem services and host exceptionally high biodiversity. These biomes are currently under immense pressure, particularly for conversion to agriculture, and already experience high global deforestation rates. Miombo forests in Southern Angola are affected by deforestation, fragmentation and degrada...

The need for operational monitoring of landscape processes on the national to global scale led to an increased demand for pixel-based composites using complete earth observation (EO) archives. Commonly, composites are generated without explicit consideration of temporal criteria but are rather based on optimizing band indices within a pre-defined t...

TFO researchers presented their respective results concerning the targets to raise the awareness of people of the values of biodiversity (A1), to reduce the rate of loss of all natural habitats (B5), to enhance the area under conservation (C11), to enhance the contribution of biodiversity to carbon storage (D15) and to enhance the level of particip...

In many parts of Africa, spatially-explicit information on plant α-diversity, i.e., the number of species in a given area, is missing as baseline information for spatial planning. We present an approach on how to combine vegetation-plot databases and remotely-sensed land surface phenology (LSP) metrics to predict plant α-diversity on a regional sca...

Satellite-derived land surface phenology (LSP) serves as a valuable input source for many environmental applications such as land cover classifications and global change studies. Commonly, LSP is derived from coarse-resolution (CR) sensors due to their well-suited temporal resolution. However, LSP is increasingly demanded at medium resolution (MR),...

Fire spread information on a large scale is still a missing key layer for a complete description of fire regimes. We developed a novel multilevel object-based methodology that extracts valuable information about fire dynamics from Moderate Resolution Imaging Spectroradiometer (MODIS) burned area data. Besides the large area capabilities, this appro...

Poster presented at the GfÖ in Göttingen 2015

We developed a spatio-temporal path reflectance climatology for use in atmospheric corrections for a Landsat pre-processing framework. The climatology is intended as a fallback strategy for aerosol estimation in bright Southern African savannah ecosys-tems where the rarity of dark objects decreases the applicability of common image-based aerosol es...

Durante um período de cinco anos (setembro de 2010 a agosto de 2015), 140 pesquisadores de oito países, 23 universidades e instituições de pesquisa adicionais, principalmente de Angola, Botsuana, Namíbia e Alemanha, realizaram o projeto de pesquisa transdisciplinar ‚The Future Okavango‘ (TFO) dentro de toda a Bacia do Okavango-Cubango. Este livro é...

Durante um período de cinco anos (setembro de 2010 a agosto de 2015), 140 pesquisadores de oito países, 23 universidades e instituições de pesquisa adicionais, principalmente de Angola, Botsuana, Namíbia e Alemanha, realizaram o projeto de pesquisa transdisciplinar ‚The Future Okavango‘ (TFO) dentro de toda a Bacia do Okavango-Cubango. Este livro é...

The Okavango catchment is a hot spot of accelerating land use change. In particular, climate predictions, demographic developments and a growing utilization of ecosystem services and functions are expected to increase pressure on resources and land. Land use conflicts, the sustenance of precarious livelihoods, deforestation of woodland savannahs, u...

We modelled species distributions of tree species in southeast Angola using solely remotely sensed predictors.

Aboveground net primary productivity (ANPP) is limited by water availability especially in dry and desert regions, and many studies have linked ANPP to current and previous “effective” rainfall events. In this study a distributed lag-model (DLM) was used to assess the impact of current and previous 16day rainfall anomalies on the Enhanced Vegetatio...

Understanding the impact of land transformation processes on ecosystem services (ESS) is an essential prerequisite for drafting and implementing sustainable land management concepts. This study presents an analysis of land transformation processes in Horqin Sandy Lands, one of the dry areas in Inner Mongolia (China). It aims at demonstrating the im...

The repopulation of abandoned areas in Angola after the 27 years of civil war led to a fast and extensive expansion of agricultural fields to meet the rising food demand. This effect is supported by the improvement of infrastructure and has a large impact on the natural vegetation.We evaluated agricultural expansion in our study area in the south o...

The landscape of the Okavango Catchment is structured much more diverse than is perceptible at first sight. From the mountainous Angolan highlands with altitudes of more than 1700 meters above sea level to less than 1000 meters at the delta and the surrounding Kalahari sands; accordingly the relief intensity decreases steadily, from high mountainou...

Trade-off analysis can be defined as an approach to natural resource management that incorporates multiple objectives for the management of a given area (and its resources) within a decision framework. The analysis of trade-off or synergetic relationships among multiple objectives for a given system is essential for the implementation of interdisci...

In order to monitor dryness stress under controlled conditions, we set up an experiment with beech seedlings in plant pots and built a platform for observing the seedlings with field imaging spectroscopy. This serves as a preparation for multi-temporal hyperspectral air- and space-borne data expected to be available in coming years. Half of the tre...

Drylands cover about 41% of the globe's surface and provide important ecosystem services, but land use and climate change exert considerable pressure on these ecosystems. Both of these drivers frequently result in gradual vegetation change and landscape-scale trend analysis based on yearly vegetation estimates can capture such changes. Such trend a...

Interpreting hyperspectral images of forests can be challenging because reference measurements are difficult to obtain. Forest stands are too high for field spectroscopy, and up-scaling leaf reflectance to canopy reflectance is not straightforward. We took reflectance, transmittance and water and chlorophyll content measurements of forest leaves co...

Als direkte Reaktion auf Klimaveränderungen, Wasserverknappung und Übernutzung von natürlichen Ressourcen werden Landdegradation und Desertifikation in den Trockengebieten der Erde als eine der größten Bedrohungen für die globale Umwelt eingeschätzt. Um nachhaltige Landmanagementstrategien zu entwickeln, ist es notwendig, die oftmals sehr komplexen...

The aim of this study was to evaluate the potentials and limits of remote sensing time series regarding change analysis of drylands. We focussed on the assessment and monitoring of land degradation using different scales of remote sensing data. Special interest was paid on how the spatial resolutions of different sensors influence the derivation of...

Diagnosis of land condition is a basic prerequisite for finding the degradation of a territory under climatic and human pressures leading to desertification. Ecosystemic approaches, such as the one presented here, address ecosystem maturity or resilience. They are low cost, not very prone to error propagation and well-suited to implementation on re...

Horqin Sandy Lands in NE-China represent a widely discussed case of ongoing land degradation which receives much attention in China and the outside world. Located in an area of strongly continental climate and extended sandy substrates, the region is undergoing substantial land use change dynamics, largely determined by political decisions and regu...

A novel multiannual land-cover-classification scheme for classifying hypertemporal image data is suggested, which is based on a supervised decision fusion (DF) approach. This DF approach comprises two steps: First, separate support vector machines (SVMs) are trained for normalized difference vegetation index (NDVI) time-series and mean annual tempe...

In this study a link was established between anomalies in climatic and Advanced Very High Resolution Radiometer (AVHRR)/Normalized Difference Vegetation Index (NDVI) data in Spain for the period from 1989 to 1999 on a monthly and annual basis using multivariate distributed lag (DL) models and generalized least‐square (GLS) parameter estimation. In...

The Japanese satellite ALOS, launched in spring 2006, is equipped with a panchromatic and multiangle remote sensing instrument (PRISM), a visible and near infrared radiometer (AVNIR-2) and a fullpoliametric L-Band radar sensor (PalSAR). In case of acquisition dates within a short time periode, this instrumentation offers the opportunity for investi...

The exceptional dry and hot summer in Europe 2003 showed apparent effects on forest ecosystems. Thus, especially for the south western part of Germany extensive damages on trees caused by the dry climatic conditions have been reported by the forest services. Particularly spruce reacts sensitive to drought stress. This is of interest since recently...

The CEFLES2 campaign during the Carbo Europe Regional Experiment Strategy was designed to provide simultaneous airborne measurements of solar induced fluorescence and CO2 fluxes. It was combined with extensive ground-based quantification of leaf- and canopy-level processes in support of ESA's Candidate Earth Explorer Mission of the "Fluorescence Ex...

In past decades, the European Mediterranean has undergone widespread land use transformations. These are largely driven by changes of socio-economic conditions, such as accession to the European Community, and had strong effects on the way the land is being used. Aiming at a systematic description of such change processes on a global level, the syn...

Land degradation is caused by and has impacts on both the social and natural components of coupled human–environment systems. However, few studies integrate both aspects simultaneously. The main objective of this study is to test a method to evaluate land degradation based on the integration of aggregate metrics of biophysical and socio-economic “d...

Land use conversions or changes of land management practices are primary drivers of global environmental change. 'Natural experiment' situations, where some conditions vary, but other potential land use determinants remain relatively constant, offer unique opportunities to study land use change, its drivers and feedbacks on human-environment system...

In the field of hydrological modelling, there is mostly a lack of spatially distributed data that may allow a detailed analysis of simulation results. This study was to demonstrate that remote sensing can partly fill this gap, as combining reflective and thermal data allows the retrieval of estimates for evapotranspiration (ET). Two Landsat-5 TM sc...

In the present study long-term variations (1989 to 2004) on the Iberian Peninsula are addressed using the "Mediterranean Extended Daily One Km AVHRR Data Set" (MEDOKADS). The Normalised Difference Vegetation Index (NDVI) was used as proxy for land surface response to precipitation variability and human activities with ecological and social impacts...

Results of ground based experiments on spectral reflectance of dock leaves using a ZEISS spectrometer MCS501 UV-NIR with 2.5 nm resolution clearly show the well known induction kinetics of chlorophyll fluorescence when dark adapted leaves were exposed to continuous illumination. This observed feature demonstrates the origin of the transient behavio...

The combined output of LADAMER should be a comprehensive as well as spatially explicit image of land degradation effects and associated processes for the relevant European Mediterranean countries, in particular for the prototype region of the Iberian Peninsula. It will hence serve as a kind of integrating project between former research approaches...