Miguel Alvarez

Miguel Alvarez
University of Bonn | Uni Bonn · Institute of Crop Science and Resource Conservation (INRES)

Dr. rer. nat.

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94
Publications
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Publications

Publications (94)
Article
Full-text available
Aims: Wetlands in East Africa are important ecosystems for biodiversity conservation and ecosystem service provisioning, yet threatened by degradation and conversion into croplands. Conservation and land use management require data on vegetation structure and dynamics. The presented work is a response to a lacking consistent classification of East...
Technical Report
Full-text available
Checklist of syntaxa recorded for the Chilean vegetation according to the Braun-Blanquet approach and supported by vegetation-plot observations in the database "sudamerica".
Technical Report
Full-text available
Detailed list of data sources for plot observations recorded for the Chilean vegetation and stored in the database "sudamerica".
Article
Full-text available
Aims : The Braun-Blanquet approach has been widely implemented to generate classification schemes at the country level and Chile is not an exception. In spite of numerous studies, a revised system for the whole country is still missing and most of the current surveys are restricted to a small set of vegetation groups or specific study sites. To fil...
Article
Full-text available
Parthenium hysterophorus L. (Asteraceae) is an invasive alien weed with detrimental effects on agricultural production, biodiversity, human and animal health, threating rural livelihoods in Asia and Africa. The problem emerged recently in the Kenyan Rift Valley, where it began to affect the landholdings of both agro-pastoralists and crop farmers. T...
Article
Full-text available
The emergence of arthropod-borne viruses (arboviruses) as linked to land-use changes, especially the growing agricultural intensification and expansion efforts in rural parts of Africa, is of growing health concern. This places an additional burden on health systems as drugs, vaccines, and effective vector-control measures against arboviruses and t...
Article
Full-text available
Questions: Vegetation-plot records provide information on presence and cover or abundance of plants co-occurring in the same community. Vegetation-plot data are spread across research groups, environmental agencies and biodiversity research centers, and thus, are rarely accessible at continental or global scales. Here we present the sPlot database,...
Article
en The spread of Prosopis juliflora in the Baringo basin, Kenya, has led to severe changes in the ecosystem with negative socio‐economic impacts. The drivers that foster the invasiveness of Prosopis are not fully understood. Thus, a method to quantify the degree of infestation will support the determination of environmental preferences and the risk...
Article
Wetlands in East Africa harbor a large biodiversity and provide diverse ecosystem services. Also, wetlands are highly suitable for crop production due to generally fertile soils and water availability. As a result of rising demand for cropland that is driven by population growth, degradation of upland areas and changing food demand patterns, wetlan...
Article
Full-text available
Taxonomic lists are crucial elements of vegetation-plot databases and provide the links between original entries, reference taxon views and different taxon concepts. We introduce the R package taxlist in the context of object-oriented modelling for taxonomic lists. This package provides a data structure based on species lists in Turboveg, which is...
Data
Applying taxlist to species lists on diversity records
Article
Full-text available
Although numerous descriptive studies have been published throughout the 20th century on peat communities in the Southern Cone of South America, the nomenclature applied to the different units recognised often fails to take into account the proposals of previous authors. Our aim is to clarify the nomenclature by applying the rules of the ICPN to pr...
Article
Aims: Wetlands in East Africa are important ecosystems providing valuable services to people living around them. Among various uses, agricultural production (cultivation and grazing) is the most frequent activity affecting the ecotone between dry land and wetland. A classification of aquatic and semi-aquatic vegetation focussing on less disturbed p...
Working Paper
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Chapter
In this chapter, based on the exhaustive bibliographical review, Chilean coastal wetlands are defined, marked off and classified, characterizing their macrophyte flora, in wetlands and marshes, starting with a brief review of morphology and simplification of the corms in these plants, and continuing with the physiology, highlighting details of hydr...
Poster
Full-text available
While flooding periods curtail cultivation, extended soil moisture availability during dry seasons make flood plains and riparian environments suitable for seasonal cropping activities and other agricultural uses. Unsustainable cultivation practices coupled with the establishment of drainage structures can however result in degradation of soil phys...
Poster
Full-text available
Land use changes and intensification driven by population growth are increasingly impairing the integrity of East African ecosystems. Diversity and functioning of habitats are directly affected by human activities and resulting changes may be reflected in the structure and floristic composition of vegetation. Thus, documentation of vegetation data...
Presentation
Full-text available
Prosopis juliflora has been reported as highly noxious invasive species in dry areas among the Tropics worldwide. In Eastern Africa, as in many other places, Prosopis species have been deliberately introduced for afforestation purposes. Due to its rapid spread by endozoochorous dispersal, fast growth and coppice ability, Prosopis became invasive, a...
Article
Prosopis juliflora is a perennial shrub introduced in the 1980s to the Baringo District in central Kenya, and became highly invasive starting around the late 1990s. This period coincides with a shift of the composition of ruminant herds from formerly cattle to goats in this area. To assess the possible role of this shift in herd structure on P. jul...
Article
The use of East African freshwater wetlands for agriculture has increased in recent decades, raising concerns about potential impacts on wetlands and the long-term sustainability of such land use trends. WET-health is an indicator-based rapid wetland assessment approach developed in South Africa. It allows determining the conditions of wetlands in...
Article
Full-text available
Biodiversity is highly valuable and critically threatened by anthropogenic degradation of the natural environment. In response, governments have pledged enhanced protected-area coverage, which requires scarce biological data to identify conservation priorities. To assist this effort, we mapped conservation priorities in Kenya based on maximizing al...
Chapter
The wetland vegetation of the Afro-(sub)alpine belt, which is dominated by tussock grassland, has embedded in it ericaceous shrubs, Helichrysum cushions and Carex bogs, which constitute small microhabitats with annuals.
Article
Full-text available
In the semi-arid savannahs around Lake Baringo, Kenya, the recent spread of bush encroachment by the invasive alien species Prosopis juliflora and the native Dodonaea viscosa has changed human–environment interactions. This article suggests how the spread dynamics of Prosopis and Dodonaea have operated. It also describes the strategies Baringo's pe...
Article
Full-text available
Structural attributes at different levels of biological organization (species, communities, landscape) and plant biodiversity are described and compared between the basins of Baker and Pascua Rivers in Aisen Region. Four hundred and ninety four vegetation samples were taken in forest ecosystems, bush, pasture, and peat to build tables of plant comm...
Chapter
The wetland vegetation of the Afro-(sub)alpine belt, which is dominated by tussock grassland, has embedded in it ericaceous shrubs, Helichrysum cushions and Carex bogs, which constitute small microhabitats with annuals. A synopsis of these annual turfs is presented in a constancy table, based upon the available plot data (168 relevés), sampled on t...
Article
Full-text available
Habitats of Schinus patagonicus and Schinus marchandii in the Chilean Patagonia were studied, in order to determine the plant communities into these species growing and the primary or secondary character of them, to help establish the conservation status of the two species. We worked with phytosociological methods to characterize floristic and vege...
Article
Full-text available
Species composition and geographical distribution of vernal pools in Mediterranean Chile are poorly studied. In order overcome this gap we collected 73 floristic samples in the Mediterranean-temperate gradient from Chile (31–44°S). Additionally, we carried out an exhaustive collection of published phytosociological relevés made in this area includi...
Article
Habitats of Schinus patagonicus and Schinus marchandii in the Chilean Patagonia were studied, in order to determinethe plant communities into these species growing and the primary or secondary character of them, to help establishthe conservation status of the two species. We worked with phytosociological methods to characterize floristic andvegetat...
Conference Paper
Full-text available
Abstract. The Late Cretaceous (Maastrichtian) Quiriquina Formation in Central Chile is well recorded around the Bay of Concepción and assigned to the late Early to Late Maastrichtian, based on a diverse ammonite assemblage. Species richness and abundance of ammonoids are high throughout the Quiriquina Formation but gradually decline in the uppermos...
Article
Full-text available
Using plant sociological data from the baseline of an aquaculture project the flora and terrestrial vegetation in five sectors of the banks of the Estero Walker, located in the western Chilean Patagonia is studied. According to a preliminary catalog the flora consisting of 68 native species, which dominate Dicotyledons, Monocotyledons and Ferns, la...
Article
Full-text available
Buglossoides arvensis (L.) I.M. Johnst. (Boraginaceae), una maleza de origen euroasiático, sólo ha sido mencionada en Sudamérica para las floras de Argentina y Uruguay. En este trabajo se amplía su distribución en el continente para Bolivia, Chile, Colombia y Perú, donde esta especie ha sido observada como maleza de cultivos y en ambientes alterado...
Article
Full-text available
Small wetlands in East Africa have grown in prominence driven by the unreliable and diminished rains and the increasing population pressure. Due to their size (less than 500 Ha), these wetlands have not been studied extensively using satellite remote sensing approaches. High spatial resolu-tion remote sensing approaches overcome this limitation all...
Article
Full-text available
Different stages of anthropogenic degradation series of one primary shrub were compared in Aisén, Chile. It consisted of a prolonged livestock pasture, with plant ecological indicators recognized and valued by Ellenberg for the factors of light, temperature and reaction, nitrogen and soil moisture. The primary ñirre thicket was considered the begin...
Article
Using plant sociological data from the baseline of an aquaculture project the flora and terrestrial vegetation in five sectors of the banks of the Estero Walker, located in the western Chilean Patagonia is studied. According to a preliminary catalog the flora consisting of 68 native species, which dominate Dicotyledons, Monocotyledons and Ferns, la...
Article
Wetlands of the river mouths along the Chilean Pacific coast are brackish that present similarities to salt marshes in terms of ecological conditions, with azonal flora and vegetation as these depend on ground water and not on macroclimate. The floristic structure along an altitudinal gradient was studied in two of such localities: Vegas del Itata...
Article
Crop cultivation under rain-fed conditions is a recent innovation among the formerly pastoral-nomadic Pokot in north-central Kenya. We have examined the socioecological dynamics of land-use change from an interdisciplinary perspective. The patterns of transition to agropastoralism are closely related to both the biogeophysical attributes of the are...
Conference Paper
Full-text available
The status of biodiversity in eastern Africa region indicates that most tropical ecosystems are losing biodiversity at an alarming rate. This has compromised ecosystems goods and services with a resultant loss of livelihoods among the local communities. The most impacted ecosystems are small wetlands of East Africa. The high production potential of...
Conference Paper
Full-text available
The status of biodiversity in eastern Africa region indicates that most tropical ecosystems are losing biodiversity at an alarming rate. This has compromised ecosystems goods and services with a resultant loss of livelihoods among the local communities. The most impacted ecosystems are small wetlands of East Africa. The high production potential of...
Conference Paper
Full-text available
In East Africa demographic growth, degradation of upland soils and inter-annual variability of rains is increasing cropping pressure on seasonal and nearly permanent wetlands. Duration and intensity of land use affect distinctly soil properties leading to negative impacts in functions of wetland ecosystems and on potential productivity of the soils...
Article
Full-text available
Invasive plant species are major drivers of biodiversity losses, especially on islands which are prone to invasions and extinctions. In the “endemic montane forest” of Robinson Crusoe Island (Pacific Ocean, Chile) invasive exotic plant species threaten conservation efforts by establishing in gaps and outcompeting native tree species regeneration. W...
Article
Full-text available
The use of mean value for the analysis of Ellenberg indicator values in plots or plant community types has been criticised by several authors. On the other hand, little attention has been paid to distribution patterns of the respective classes’ frequencies. Herewith we make a revision of metrics available for the characterization of tendency and di...
Article
Full-text available
Small wetlands in East Africa are increasingly converted into sites for agricultural production. The resulting changes in land use and cropping systems will impact on the wetlands’ vegetation. We characterized the plant communities in four wetlands of Kenya and Tanzania, each comprising four types of land use differentiated by the degree of anthrop...
Article
Full-text available
SWEA (agricultural use and vulnerability of small wetlands in East Africa) is a multidisciplinary project which task is to evaluate the effects of land use on the ecological and socio-economical functions of small wetlands in Kenya and Tanzania. In order to allow the availability of the collected data for further studies we stored them into SWEA-Da...
Article
Full-text available
Introduction The logging of several spruce plantations is planned for the next years in the Eifel National Park (Western Germany). To understand the ecological mechanisms of spontaneous forest regeneration that follows these impacts, it is crucial to investigate the species composition and functional diversity of the buried germinable seeds in thos...
Article
Minute size (nanism) and short live cycle (ephemerism) are characteristic features of many plants living in seasonal wetlands in Mediterranean biomes. Lepuropetalon (Celastraceae) is a monotypic genus with an antitropical distribution (disjunct in temperate regions of both Americas). L. spathulatum is the smallest vascular plant of Chile, not recor...
Article
We studied the dynamic of the vegetation degradation in a rural anthropogenic mosaic vegetal landscape of the Aisen Region, Chile to establish relations of origin in space and time between communities and propose series of degradation. With plant sociological methodology we make up 50 vegetation samples. The initial table was sorted using different...
Article
Full-text available
Small wetlands in Kenya and Tanzania cover about 12 million ha and are increasingly converted for agricultural production. There is a need to provide guide-lines for their future protection or use, requiring their systematic classification and characterisation. Fifty-one wetlands were inventoried in 2008 in four contrasting sites, covering a survey...
Article
Full-text available
We studied the dynamic of the vegetation degradation in a rural anthropogenic mosaic vegetal landscape of the Aisen Region, Chile to establish relations of origin in space and time between communities and propose series of degradation. With plant sociological methodology we make up 50 vegetation samples. The initial table was sorted using different...
Article
Until now, the vegetation of seasonal wetlands in South America has only been studied on local to regional scales. A synoptic view is lacking and the distribution of vegetation types remains unknown. Hence we attempt here to detect floristic patterns on the spatial dimension of the subcontinent and to identify the environmental factors behind them....
Article
Full-text available
We studied the abundance, phytogeographycal origin, biological spectrum and the habitats of the aquatic macrophyte flora in the limnic (lotic and lentic) wetlands and in salt marshes of the Aisén Region, Chile. We found 86 species of vascular macrophytes including in 54 genera and 33 families. Only 8 species are abundant (Myriophyllum quitense, Pot...