Trees, Grasses and Crops. People and Plants in Sub-Saharan Africa and Beyond, 2019
Front cover: Photos by Hans-Peter Wotzka (Baobab, Adansonia digitata, Gobnangou region, east of K... more Front cover: Photos by Hans-Peter Wotzka (Baobab, Adansonia digitata, Gobnangou region, east of Kantchari, Burkina Faso, 1989) and Jennifer Markwirth (various infructescences of Sorghum, Sorghum bicolor and one of pearl millet, Cenchrus americanus, syn. Pennisetum glaucum).
To improve data availability and exchange in the area of the WAP complex, West Africa's largest c... more To improve data availability and exchange in the area of the WAP complex, West Africa's largest continuous area of reserves, we set up a citizen science project on the iNaturalist platform, allowing contribution of observations, ideally documented by photographs and/or sounds. Along with the project we created a number of online field guides for the local flora. Within only two months, 852 observations of 312 species have been assembled. We expect this dataset to further grow in the future and complement existing data sets from scientific collections and surveys. Résumé: Afin d'améliorer la disponibilité et l'échange de données dans le domaine du complexe WAP, le plus grand complex d'aires protégées en Afrique de l'Ouest, nous avons mis en place un projet scientifique citoyen sur la plate-forme iNaturaliste. Parallèlement à ce projet, un certain nombre de guides de terrain ont été créé en ligne pour la flore locale. En deux mois déjà, 852 observations sur 312 espèces ont été rassemblées. Nous espérons pour l'avenir une croissance continue de cette base de données qui sera également complétée par celles existantes au niveau des collections et travaux scientifiques.
Sudanian Savannas are under high agricultural pressure and are therefore changing rapidly. Due to... more Sudanian Savannas are under high agricultural pressure and are therefore changing rapidly. Due to high population densities and an increasing need for food and cash crops, the mosaic of traditional agroforestry systems, fallows and savanna is being transformed into intensively used croplands and savannas only remain in protected areas. e focus of this study is to characterize the differences in plant diversity and composition between protected areas and surrounding agricultural lands and to identify areas most important for plant conservation. Building on observation and collection records, we modelled distributions of individual plant species and summarized these. We mapped the species richness of vascular plants in general, of woody plants, graminoids and forbs, the share of weeds and the average size of grasses and trees and calculated means for the reserves and outside areas. Distinct differences between protected areas and agricultural lands have been found in the richness of herbs (both forbs and graminoids) and weeds as well as in the size of grasses : Woody species seem to be less affected by human impact in the agricultural lands concerning both species richness and plant size. Weeds are playing an important role in the higher species richness of the agricultural lands.
RÉSUMÉ L'herbier est un outil fondamental pour la gestion de la diversité végétale. C'est pour ce... more RÉSUMÉ L'herbier est un outil fondamental pour la gestion de la diversité végétale. C'est pour cela qu'il convient d'outiller les gestionnaires forestiers et les botanistes débutants sur les bonnes pratiques en matière d'herborisation et de préparation des échantillons d'herbier. C'est l'objet du présent article qui informe sur le concept et l'importance de l'herbier et donne des indications sur les pratiques à adopter au cours des différentes étapes de sa réalisation. Le matériel nécessaire étant réuni, les étapes fondamentales pour la réalisation d'un herbier sont l'herborisation, les informations de terrain à noter, le séchage et pressage des échantillons, le montage, l'étiquetage et la conservation des spécimens. Pour chaque étape, le matériel technique utilisé est cité ainsi que les méthodes pour parvenir à la réalisation d'une bonne collection d'herbier. ABSTRACT The herbarium is a fundamental tool for the management of plant diversity. That is why it is appropriate to empower forest managers and novice botanists on good practices for preparing herbarium samples. This is the aim of this paper that provides information on the concept and importance of herbarium and provides guidance on the practices to adopt during the different steps of its implementation. Having the necessary equipment, the basic steps for making a herbarium are specimen collection, field information gathering, drying and pressing, assembling, labeling and packing specimens. For each step, the technical equipment is cited and the methods to achieve the realization of a good herbarium collection are described.
Although there is an increasing need for data in ecological studies, many datasets are still lost... more Although there is an increasing need for data in ecological studies, many datasets are still lost or not sufficiently visible due to a lack of appropriate data archives. With the West African Data and Metadata Repository, we present a secure long-term archive for a data-poor region allowing detailed documentation by metadata following the EML standard and giving data holders the opportunity to define levels of data access and conditions of use. This article gives an overview of structure, functions and content. The repository is online at the URL http://westafricandata.senckenberg.de.
To determine the resilience of soil organic C and N pools during land degradation processes in a ... more To determine the resilience of soil organic C and N pools during land degradation processes in a semi-arid landscape of West Africa, we compared the magnitude of soil organic C and N differences in bulk soil and aggregate fractions between contrasting types of land cover (degraded land and native land cover) and soil (Luvisols and Cambisols). We analyzed the following soil key indicators: CEC, soil respiration, C and N contents, and δ13C and δ15N signatures of soil organic C. The average CO2 respired from native land cover was at least 82% higher than its value from degraded land cover andwas significantly higher in Luvisols than in Cambisols. Likewise, the soil organic C and N contents in bulk soil were significantly affected by land cover and soil contrasts. The average C loss in bulk soil from degraded land cover was equivalent to 49% in Cambisols and 54% in Luvisols. In both soil types, all aggregate fractions were sensitive to land degradation processes and the C loss decreased from macroaggregates to the clay + silt fraction. Compared to the native land cover, organic C loss from the macroaggregates in degraded land cover was 92% and 84%, respectively, in Cambisols and Luvisols. The soil type affected significantly the C content only in the clay + silt fraction. The C/N ratio of finer fractions (microaggregates and clay + silt) was significantly higher in degraded land cover than in native land cover, indicating greater losses of N than C during land degradation processes. The differences of δ13C signatures throughout C pools between the two types of land cover suggest a relative dominance of C3 derived C inmacroaggregates and C4 derived C in the clay+silt fraction in the degraded lands. The reduction of soil respiration and the rapid N loss in degraded land cover slowed downthe humification processes of C3 plant derived materials which were effectively dominant in macroaggregates.
Detailed plant diversity information is lacking for Africa, as for many other regions in the trop... more Detailed plant diversity information is lacking for Africa, as for many other regions in the tropics, therefore we have used our collection and observation databases to search for possible indicator groups. Digitization of specimen label data for Burkina Faso from the Herbarium Senckenbergianum (FR) and the Ouagadougou University Herbarium (OUA) led to a database containing 18 000 specimens. Field observations from about 3700 relevés (Braun-Blanquet method, BIOTA standard relevés, simple inventories) were added to the database and together used to model potential species distributions for Burkina Faso on a ten-minute grid. Genetic Algorithm for Rule-set Production (GARP) was used with temperature, precipitation, humidity, and elevation data. Based on these modeled distributions, overall vascular plant diversity was correlated to the diversities of the ten commonest families (Poaceae, Fabaceae, Cyperaceae, Rubiaceae, Combretaceae, Euphorbiaceae, Mimosaceae, Asteraceae, Caesalpiniaceae, Malvaceae). Poaceae and Fabaceae turned out to be the most suitable taxa. The value of these families as indicators for assessing biodiversity is discussed. The results are compared to similar analyses based on relevés only.
Seit 2008 gibt es eine umfangreiche Fotodatenbank zu den Pflanzen Westafrikas, die online von Wis... more Seit 2008 gibt es eine umfangreiche Fotodatenbank zu den Pflanzen Westafrikas, die online von Wissenschaftlern und Laien genutzt werden kann. Mit bisher mehr als 140.000 Besuchen haben botanisch Interessierte das Portal „www.westafricanplants.senckenberg.de“ gut angenommen. Nun ist dieses virtuelle Bestimmungs-„Buch“ um die Regionen Zentral- und Ostafrika erweitert worden.
Based on extensive fieldwork in the last 20 years, we present an updated checklist of the Vascula... more Based on extensive fieldwork in the last 20 years, we present an updated checklist of the Vascular Plants of Burkina Faso, including relevant synonymy, references and iconography. Additionally informations on life-form, vernacular names, economic value, medicinal and cultural uses, habitat and distribution were added, based on literature and own studies. Furthermore, the investigated herbarium specimens are listed under each species. The flora now amounts to 2067 species, that is an increase of 70% compared to the last comprehensive list by LEBRUN & al. from 1991, which has been an essential scientific base for the presented checklist. The checklist updates our knowledge about the plant diversity of Burkina Faso, is expected to aid biodiversity conservation issues considerably and is intended to be a first, essential step towards the long-term project of a “Flore analytique du Burkina Faso”. Nous présentons la version actualisée du catalogue des plantes vasculaires du Burkina Faso e...
The distribution of 18 species of Combretaceae occurring in Burkina Faso is determined through th... more The distribution of 18 species of Combretaceae occurring in Burkina Faso is determined through the countrywide prospection, location and description of different species populations. A total of 902 sites and 2705 populations has been characterized through a codification based on the abundance of individuals. Real distribution of species has been achieved by projection of observation points and the potential area of distribution by GARP modelling considering population characteristics and climatic factors taken into account. The Combretaceae specific richness is also evaluated in each climatic zone of the country.
Question: How can quantitative data from vegetation surveys best be assembled in a large regional... more Question: How can quantitative data from vegetation surveys best be assembled in a large regional vegetation database? What effects have intellectual property rights concerns of individual and institutional data holders on data contribution and how can incentives to contribute data be generated?
We combined grass (Poaceae) occurrence data from the Sahelian parts of Burkina Faso, West Africa,... more We combined grass (Poaceae) occurrence data from the Sahelian parts of Burkina Faso, West Africa, with data on the photosynthetic type of these species. Occurrence data were compiled from relevés and collections of the Herbarium Senckenbergianum, and the assignment of photosynthetic types was taken from the literature and completed by leaf anatomical observations of our own. We used the occurrence data to model species distributions using GARP (Genetic algorithm of rule-set production) and high-resolution satellite data (Landsat ETM+) as environmental predictors. In a subsequent step we summarized the distributions of single species for each photosynthetic type. The resulting distribution patterns reflect the ecological preferences connected with photosynthetic pathways. The only C3 species is strictly bound to watercourses and temporary lakes, C4 MS species mainly occur on the dunes, C4 PS-PCK species are mainly from dunes and watercourses, C4 PS-NAD type species dominate the drier...
The partial faunal reserve of Pama is situated in the province of Kompienga, in the South-East of... more The partial faunal reserve of Pama is situated in the province of Kompienga, in the South-East of Burkina Faso, with typical Sudanian savanna vegetation. Adjacent to the Arli National Park and the Pendjari National Park, it is part of the so-called WAP complex, one of the largest wildlife areas in West Africa. Up to now, only little has been known about its flora. The present study aimed at reducing this gap in knowledge, and represents an important tool for conservation and research. The list of species was compiled from the surveys carried out from 2001 to 2004, additional relevé data, and herbarium specimens. We found 450 species, which belong to 244 genera and 73 families. The most species-rich family is Poaceae (83 species), followed by Fabaceae (64), Cyperaceae (24), Rubiaceae (22), Euphor- biaceae (20), Combretaceae (15), Asteraceae (14), Caesalpiniaceae (14), Mimosaceae (12), and Convolvulaceae (11).
Background: The West African country of Burkina Faso (BFA) is an example for the enduring importa... more Background: The West African country of Burkina Faso (BFA) is an example for the enduring importance of traditional plant use today. A large proportion of its 17 million inhabitants lives in rural communities and strongly depends on local plant products for their livelihood. However, literature on traditional plant use is still scarce and a comprehensive analysis for the country is still missing.
Boussim J.I., 2015. Land cover change and plants diversity in the Sahel: A case study from northe... more Boussim J.I., 2015. Land cover change and plants diversity in the Sahel: A case study from northern Burkina Faso. Ann. For. Res. 58(1): _-_ 2015.
Trees, Grasses and Crops. People and Plants in Sub-Saharan Africa and Beyond, 2019
Front cover: Photos by Hans-Peter Wotzka (Baobab, Adansonia digitata, Gobnangou region, east of K... more Front cover: Photos by Hans-Peter Wotzka (Baobab, Adansonia digitata, Gobnangou region, east of Kantchari, Burkina Faso, 1989) and Jennifer Markwirth (various infructescences of Sorghum, Sorghum bicolor and one of pearl millet, Cenchrus americanus, syn. Pennisetum glaucum).
To improve data availability and exchange in the area of the WAP complex, West Africa's largest c... more To improve data availability and exchange in the area of the WAP complex, West Africa's largest continuous area of reserves, we set up a citizen science project on the iNaturalist platform, allowing contribution of observations, ideally documented by photographs and/or sounds. Along with the project we created a number of online field guides for the local flora. Within only two months, 852 observations of 312 species have been assembled. We expect this dataset to further grow in the future and complement existing data sets from scientific collections and surveys. Résumé: Afin d'améliorer la disponibilité et l'échange de données dans le domaine du complexe WAP, le plus grand complex d'aires protégées en Afrique de l'Ouest, nous avons mis en place un projet scientifique citoyen sur la plate-forme iNaturaliste. Parallèlement à ce projet, un certain nombre de guides de terrain ont été créé en ligne pour la flore locale. En deux mois déjà, 852 observations sur 312 espèces ont été rassemblées. Nous espérons pour l'avenir une croissance continue de cette base de données qui sera également complétée par celles existantes au niveau des collections et travaux scientifiques.
Sudanian Savannas are under high agricultural pressure and are therefore changing rapidly. Due to... more Sudanian Savannas are under high agricultural pressure and are therefore changing rapidly. Due to high population densities and an increasing need for food and cash crops, the mosaic of traditional agroforestry systems, fallows and savanna is being transformed into intensively used croplands and savannas only remain in protected areas. e focus of this study is to characterize the differences in plant diversity and composition between protected areas and surrounding agricultural lands and to identify areas most important for plant conservation. Building on observation and collection records, we modelled distributions of individual plant species and summarized these. We mapped the species richness of vascular plants in general, of woody plants, graminoids and forbs, the share of weeds and the average size of grasses and trees and calculated means for the reserves and outside areas. Distinct differences between protected areas and agricultural lands have been found in the richness of herbs (both forbs and graminoids) and weeds as well as in the size of grasses : Woody species seem to be less affected by human impact in the agricultural lands concerning both species richness and plant size. Weeds are playing an important role in the higher species richness of the agricultural lands.
RÉSUMÉ L'herbier est un outil fondamental pour la gestion de la diversité végétale. C'est pour ce... more RÉSUMÉ L'herbier est un outil fondamental pour la gestion de la diversité végétale. C'est pour cela qu'il convient d'outiller les gestionnaires forestiers et les botanistes débutants sur les bonnes pratiques en matière d'herborisation et de préparation des échantillons d'herbier. C'est l'objet du présent article qui informe sur le concept et l'importance de l'herbier et donne des indications sur les pratiques à adopter au cours des différentes étapes de sa réalisation. Le matériel nécessaire étant réuni, les étapes fondamentales pour la réalisation d'un herbier sont l'herborisation, les informations de terrain à noter, le séchage et pressage des échantillons, le montage, l'étiquetage et la conservation des spécimens. Pour chaque étape, le matériel technique utilisé est cité ainsi que les méthodes pour parvenir à la réalisation d'une bonne collection d'herbier. ABSTRACT The herbarium is a fundamental tool for the management of plant diversity. That is why it is appropriate to empower forest managers and novice botanists on good practices for preparing herbarium samples. This is the aim of this paper that provides information on the concept and importance of herbarium and provides guidance on the practices to adopt during the different steps of its implementation. Having the necessary equipment, the basic steps for making a herbarium are specimen collection, field information gathering, drying and pressing, assembling, labeling and packing specimens. For each step, the technical equipment is cited and the methods to achieve the realization of a good herbarium collection are described.
Although there is an increasing need for data in ecological studies, many datasets are still lost... more Although there is an increasing need for data in ecological studies, many datasets are still lost or not sufficiently visible due to a lack of appropriate data archives. With the West African Data and Metadata Repository, we present a secure long-term archive for a data-poor region allowing detailed documentation by metadata following the EML standard and giving data holders the opportunity to define levels of data access and conditions of use. This article gives an overview of structure, functions and content. The repository is online at the URL http://westafricandata.senckenberg.de.
To determine the resilience of soil organic C and N pools during land degradation processes in a ... more To determine the resilience of soil organic C and N pools during land degradation processes in a semi-arid landscape of West Africa, we compared the magnitude of soil organic C and N differences in bulk soil and aggregate fractions between contrasting types of land cover (degraded land and native land cover) and soil (Luvisols and Cambisols). We analyzed the following soil key indicators: CEC, soil respiration, C and N contents, and δ13C and δ15N signatures of soil organic C. The average CO2 respired from native land cover was at least 82% higher than its value from degraded land cover andwas significantly higher in Luvisols than in Cambisols. Likewise, the soil organic C and N contents in bulk soil were significantly affected by land cover and soil contrasts. The average C loss in bulk soil from degraded land cover was equivalent to 49% in Cambisols and 54% in Luvisols. In both soil types, all aggregate fractions were sensitive to land degradation processes and the C loss decreased from macroaggregates to the clay + silt fraction. Compared to the native land cover, organic C loss from the macroaggregates in degraded land cover was 92% and 84%, respectively, in Cambisols and Luvisols. The soil type affected significantly the C content only in the clay + silt fraction. The C/N ratio of finer fractions (microaggregates and clay + silt) was significantly higher in degraded land cover than in native land cover, indicating greater losses of N than C during land degradation processes. The differences of δ13C signatures throughout C pools between the two types of land cover suggest a relative dominance of C3 derived C inmacroaggregates and C4 derived C in the clay+silt fraction in the degraded lands. The reduction of soil respiration and the rapid N loss in degraded land cover slowed downthe humification processes of C3 plant derived materials which were effectively dominant in macroaggregates.
Detailed plant diversity information is lacking for Africa, as for many other regions in the trop... more Detailed plant diversity information is lacking for Africa, as for many other regions in the tropics, therefore we have used our collection and observation databases to search for possible indicator groups. Digitization of specimen label data for Burkina Faso from the Herbarium Senckenbergianum (FR) and the Ouagadougou University Herbarium (OUA) led to a database containing 18 000 specimens. Field observations from about 3700 relevés (Braun-Blanquet method, BIOTA standard relevés, simple inventories) were added to the database and together used to model potential species distributions for Burkina Faso on a ten-minute grid. Genetic Algorithm for Rule-set Production (GARP) was used with temperature, precipitation, humidity, and elevation data. Based on these modeled distributions, overall vascular plant diversity was correlated to the diversities of the ten commonest families (Poaceae, Fabaceae, Cyperaceae, Rubiaceae, Combretaceae, Euphorbiaceae, Mimosaceae, Asteraceae, Caesalpiniaceae, Malvaceae). Poaceae and Fabaceae turned out to be the most suitable taxa. The value of these families as indicators for assessing biodiversity is discussed. The results are compared to similar analyses based on relevés only.
Seit 2008 gibt es eine umfangreiche Fotodatenbank zu den Pflanzen Westafrikas, die online von Wis... more Seit 2008 gibt es eine umfangreiche Fotodatenbank zu den Pflanzen Westafrikas, die online von Wissenschaftlern und Laien genutzt werden kann. Mit bisher mehr als 140.000 Besuchen haben botanisch Interessierte das Portal „www.westafricanplants.senckenberg.de“ gut angenommen. Nun ist dieses virtuelle Bestimmungs-„Buch“ um die Regionen Zentral- und Ostafrika erweitert worden.
Based on extensive fieldwork in the last 20 years, we present an updated checklist of the Vascula... more Based on extensive fieldwork in the last 20 years, we present an updated checklist of the Vascular Plants of Burkina Faso, including relevant synonymy, references and iconography. Additionally informations on life-form, vernacular names, economic value, medicinal and cultural uses, habitat and distribution were added, based on literature and own studies. Furthermore, the investigated herbarium specimens are listed under each species. The flora now amounts to 2067 species, that is an increase of 70% compared to the last comprehensive list by LEBRUN & al. from 1991, which has been an essential scientific base for the presented checklist. The checklist updates our knowledge about the plant diversity of Burkina Faso, is expected to aid biodiversity conservation issues considerably and is intended to be a first, essential step towards the long-term project of a “Flore analytique du Burkina Faso”. Nous présentons la version actualisée du catalogue des plantes vasculaires du Burkina Faso e...
The distribution of 18 species of Combretaceae occurring in Burkina Faso is determined through th... more The distribution of 18 species of Combretaceae occurring in Burkina Faso is determined through the countrywide prospection, location and description of different species populations. A total of 902 sites and 2705 populations has been characterized through a codification based on the abundance of individuals. Real distribution of species has been achieved by projection of observation points and the potential area of distribution by GARP modelling considering population characteristics and climatic factors taken into account. The Combretaceae specific richness is also evaluated in each climatic zone of the country.
Question: How can quantitative data from vegetation surveys best be assembled in a large regional... more Question: How can quantitative data from vegetation surveys best be assembled in a large regional vegetation database? What effects have intellectual property rights concerns of individual and institutional data holders on data contribution and how can incentives to contribute data be generated?
We combined grass (Poaceae) occurrence data from the Sahelian parts of Burkina Faso, West Africa,... more We combined grass (Poaceae) occurrence data from the Sahelian parts of Burkina Faso, West Africa, with data on the photosynthetic type of these species. Occurrence data were compiled from relevés and collections of the Herbarium Senckenbergianum, and the assignment of photosynthetic types was taken from the literature and completed by leaf anatomical observations of our own. We used the occurrence data to model species distributions using GARP (Genetic algorithm of rule-set production) and high-resolution satellite data (Landsat ETM+) as environmental predictors. In a subsequent step we summarized the distributions of single species for each photosynthetic type. The resulting distribution patterns reflect the ecological preferences connected with photosynthetic pathways. The only C3 species is strictly bound to watercourses and temporary lakes, C4 MS species mainly occur on the dunes, C4 PS-PCK species are mainly from dunes and watercourses, C4 PS-NAD type species dominate the drier...
The partial faunal reserve of Pama is situated in the province of Kompienga, in the South-East of... more The partial faunal reserve of Pama is situated in the province of Kompienga, in the South-East of Burkina Faso, with typical Sudanian savanna vegetation. Adjacent to the Arli National Park and the Pendjari National Park, it is part of the so-called WAP complex, one of the largest wildlife areas in West Africa. Up to now, only little has been known about its flora. The present study aimed at reducing this gap in knowledge, and represents an important tool for conservation and research. The list of species was compiled from the surveys carried out from 2001 to 2004, additional relevé data, and herbarium specimens. We found 450 species, which belong to 244 genera and 73 families. The most species-rich family is Poaceae (83 species), followed by Fabaceae (64), Cyperaceae (24), Rubiaceae (22), Euphor- biaceae (20), Combretaceae (15), Asteraceae (14), Caesalpiniaceae (14), Mimosaceae (12), and Convolvulaceae (11).
Background: The West African country of Burkina Faso (BFA) is an example for the enduring importa... more Background: The West African country of Burkina Faso (BFA) is an example for the enduring importance of traditional plant use today. A large proportion of its 17 million inhabitants lives in rural communities and strongly depends on local plant products for their livelihood. However, literature on traditional plant use is still scarce and a comprehensive analysis for the country is still missing.
Boussim J.I., 2015. Land cover change and plants diversity in the Sahel: A case study from northe... more Boussim J.I., 2015. Land cover change and plants diversity in the Sahel: A case study from northern Burkina Faso. Ann. For. Res. 58(1): _-_ 2015.
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Papers by Marco Schmidt
visible due to a lack of appropriate data archives. With the West African Data and Metadata Repository, we present a secure long-term archive for a data-poor region allowing detailed documentation by metadata following the EML standard and giving data holders the opportunity to define levels of data access and conditions of use. This article gives an overview of structure, functions and content. The repository is online at the URL http://westafricandata.senckenberg.de.
of West Africa, we compared the magnitude of soil organic C and N differences in bulk soil and aggregate
fractions between contrasting types of land cover (degraded land and native land cover) and soil (Luvisols and
Cambisols). We analyzed the following soil key indicators: CEC, soil respiration, C and N contents, and δ13C and
δ15N signatures of soil organic C.
The average CO2 respired from native land cover was at least 82% higher than its value from degraded land cover
andwas significantly higher in Luvisols than in Cambisols. Likewise, the soil organic C and N contents in bulk soil
were significantly affected by land cover and soil contrasts. The average C loss in bulk soil from degraded land
cover was equivalent to 49% in Cambisols and 54% in Luvisols. In both soil types, all aggregate fractions were sensitive
to land degradation processes and the C loss decreased from macroaggregates to the clay + silt fraction.
Compared to the native land cover, organic C loss from the macroaggregates in degraded land cover was 92%
and 84%, respectively, in Cambisols and Luvisols. The soil type affected significantly the C content only in the
clay + silt fraction. The C/N ratio of finer fractions (microaggregates and clay + silt) was significantly higher
in degraded land cover than in native land cover, indicating greater losses of N than C during land degradation
processes. The differences of δ13C signatures throughout C pools between the two types of land cover suggest a
relative dominance of C3 derived C inmacroaggregates and C4 derived C in the clay+silt fraction in the degraded
lands. The reduction of soil respiration and the rapid N loss in degraded land cover slowed downthe humification
processes of C3 plant derived materials which were effectively dominant in macroaggregates.
visible due to a lack of appropriate data archives. With the West African Data and Metadata Repository, we present a secure long-term archive for a data-poor region allowing detailed documentation by metadata following the EML standard and giving data holders the opportunity to define levels of data access and conditions of use. This article gives an overview of structure, functions and content. The repository is online at the URL http://westafricandata.senckenberg.de.
of West Africa, we compared the magnitude of soil organic C and N differences in bulk soil and aggregate
fractions between contrasting types of land cover (degraded land and native land cover) and soil (Luvisols and
Cambisols). We analyzed the following soil key indicators: CEC, soil respiration, C and N contents, and δ13C and
δ15N signatures of soil organic C.
The average CO2 respired from native land cover was at least 82% higher than its value from degraded land cover
andwas significantly higher in Luvisols than in Cambisols. Likewise, the soil organic C and N contents in bulk soil
were significantly affected by land cover and soil contrasts. The average C loss in bulk soil from degraded land
cover was equivalent to 49% in Cambisols and 54% in Luvisols. In both soil types, all aggregate fractions were sensitive
to land degradation processes and the C loss decreased from macroaggregates to the clay + silt fraction.
Compared to the native land cover, organic C loss from the macroaggregates in degraded land cover was 92%
and 84%, respectively, in Cambisols and Luvisols. The soil type affected significantly the C content only in the
clay + silt fraction. The C/N ratio of finer fractions (microaggregates and clay + silt) was significantly higher
in degraded land cover than in native land cover, indicating greater losses of N than C during land degradation
processes. The differences of δ13C signatures throughout C pools between the two types of land cover suggest a
relative dominance of C3 derived C inmacroaggregates and C4 derived C in the clay+silt fraction in the degraded
lands. The reduction of soil respiration and the rapid N loss in degraded land cover slowed downthe humification
processes of C3 plant derived materials which were effectively dominant in macroaggregates.