Hemp Andreas

University of Bayreuth · Plant Systematics

Forests are a substantial terrestrial carbon sink, but anthropogenic changes in land use and climate have considerably reduced the scale of this system¹. Remote-sensing estimates to quantify carbon losses from global forests2–5 are characterized by considerable uncertainty and we lack a comprehensive ground-sourced evaluation to benchmark these est...

Two epiphytic Leptogium species from East Africa, both with transversely septate ascospores, are here described as new. They produce plicate thalli and have a paraplectenchymatous proper exciple and a one cell layer thick cortex on the thalline exciple. Leptogium bellum has so far only been collected from Mt. Kilimanjaro, Tanzania, where it occurs...

Understanding what controls global leaf type variation in trees is crucial for comprehending their role in terrestrial ecosystems, including carbon, water and nutrient dynamics. Yet our understanding of the factors influencing forest leaf types remains incomplete, leaving us uncertain about the global proportions of needle-leaved, broadleaved, ever...

Isoglossa pareensis I.Darbysh. & Hemp (Acanthaceae), from submontane moist forest at Mwala in the South Pare Mountains of northeastern Tanzania, is described and illustrated. This species is considered to be related to I. gregorii (S.Moore) Lindau and I. punctata (Vahl) Brummitt & J.R.I.Wood, which are widespread in the montane forests of eastern A...

Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species1,2. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies3,4. Here, leveraging global tree databases5-7, we explore how the phy...

Biodiversity is an important component of natural ecosystems, with higher species richness often correlating with an increase in ecosystem productivity. Yet, this relationship varies substantially across environments, typically becoming less pronounced at high levels of species richness. However, species richness alone cannot reflect all important...

Tropical forests are threatened by anthropogenic activities such as conversion into agricultural land, logging and fires. Land-use change and disturbance affect ecosystems not only aboveground, but also belowground including the ecosystems' carbon and nitrogen cycle. We studied the impact of different types of land-use change (intensive and traditi...

Tropical agroforestry systems support the wellbeing of many smallholder farmers. These systems provide smallholders with crops for consumption and income through their ecological interactions between their tree, soil, and crop components. These interactions, however, could be vulnerable to changes in climate conditions; yet a reliable understanding...

The lichen flora of Africa is still poorly known. In many parts of the tropics, recent studies utilizing DNA methods have revealed extraordinary diversity among various groups of lichenized fungi, including the genus Sticta. In this study, East African Sticta species and their ecology are reviewed using the genetic barcoding marker nuITS and morpho...

Tropical mountain forests are hotspots of biodiversity that are widely threatened by human population pressure and climate change. However, the cryptogamic species richness of many tropical mountain regions is insufficiently known, the poorly understood biodiversity of tropical African lichens being a prime example. To study the diversity of the ge...

The continuous decline and degradation of tropical rainforests is currently mainly driven by land-use change. Over the long term, climate change will further exacerbate the situation for the remaining forests. To develop sustainable conservation strategies, we need to understand the natural forest-recovery potential after disturbance and the impact...

Hemp 7152, a sterile herbarium plot voucher of a shrub from a rare type of deciduous forest in the Usambara Mts, Tanzania was tentatively identified using morphology as a new species of Vepris (Rutaceae). To gain further support for its placement its chemistry was investigated. The compounds isolated from Hemp 7152 were four quinoline alkaloids, ko...

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we...

Rhipidoglossum pareense, a new species, is described from the Pare mountains of NE Tanzania and compared with R. leedalii (P.J.Cribb) Farminhão & Stévart. Its habitat requirements and conservation status are assessed.

Data capturing multiple axes of tree size and shape, such as a tree's stem diameter, height and crown size, underpin a wide range of ecological research - from developing and testing theory on forest structure and dynamics, to estimating forest carbon stocks and their uncertainties, and integrating remote sensing imagery into forest monitoring prog...

Land use change and intensification are the most important direct drivers of decreasing biodiversity globally. Therefore, the European Union created the Natura 2000 network to protect endangered species and habitats. Here we are interested how the ambitious European goals are actually implemented studying a Natura 2000 habitat, the “Sarmatic steppe...

One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknow...

Effective approaches towards sustainability need to be informed by a diverse array of stakeholder perspectives. However, capturing these perspectives in a way that can be integrated with other forms of knowledge can represent a challenge. Here we present the first application of the conceptual framework of the Intergovernmental Science‐Policy Platf...

One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknow...

The monitoring of species and functional diversity is of increasing relevance for the development of strategies for the conservation and management of biodiversity. Therefore, reliable estimates of the performance of monitoring techniques across taxa become important. Using a unique dataset, this study investigates the potential of airborne LiDAR-d...

Significance Tree diversity is fundamental for forest ecosystem stability and services. However, because of limited available data, estimates of tree diversity at large geographic domains still rely heavily on published lists of species descriptions that are geographically uneven in coverage. These limitations have precluded efforts to generate a g...

Deadwood is an important structural and functional component of forest ecosystems and biodiversity. As deadwood can make up large portions of the total aboveground biomass, it plays an important role in the terrestrial carbon (C) cycle. Nevertheless, in tropical ecosystems and especially in Africa, quantitative studies on this topic remain scarce....

Land use change and intensification are the most important direct drivers of decreasing biodiversity globally. Therefore, the European Union created the Natura 2000 network to protect endangered species and habitats. Here we are interested how the ambitious European goals are actually implemented studying a Natura 2000 habitat, the “Sarmatic steppe...

The Scientific Station Nkweseko is one of few field stations in Tanzania. It is located at the lower border of the montane rain forest surrounding Mt. Kilimanjaro, protected as a National Park and a designated UNESCO world heritage site. The station itself lies in the so-called Chagga Homegardens, a sustainable agroforestry system with high biodive...

Many experiments have shown that biodiversity enhances ecosystem functioning. However, we have little understanding of how environmental heterogeneity shapes the effect of diversity on ecosystem functioning and to what extent this diversity effect is mediated by variation in species richness or species turnover. This knowledge is crucial to scaling...

One of the few general patterns in ecology is the increase of species richness with area. However, factors driving species-area relationship (SAR) are under debate, and the role of human-induced changes has been overlooked so far. Furthermore, SAR studies in tropical regions, in particular in multilayered rain forests are scarce. On the other side,...

Given the current challenges of global change, e.g., through increasing temperatures and changes in habitat quality, it is essential to gain a better understanding of how species are linked to the conditions of their environment. Bats and birds fulfill crucial ecosystem functions as highly mobile long-distance seed dispersers, pollinators, and inse...

One of the few general patterns in ecology is the increase of species richness with area. However, factors driving species-area relationship (SAR) are under debate, and the role of human-induced changes has been overlooked so far. Furthermore, SAR studies in tropical regions, in particular in multilayered rain forests are scarce. On the other side,...

Aim The identification of the mechanisms determining spatial variation in biological diversity along elevational gradients is a central objective in ecology and biogeography. Here, we disentangle the direct and indirect effects of abiotic drivers (climatic conditions, and land use) and biotic drivers (vegetation structure and food resources) on fun...

The amount of carbon stored in deadwood is equivalent to about 8 per cent of the global forest carbon stocks1. The decomposition of deadwood is largely governed by climate2–5 with decomposer groups—such as microorganisms and insects—contributing to variations in the decomposition rates2,6,7. At the global scale, the contribution of insects to the d...

Tropical forests store 40-50% of terrestrial vegetation carbon. Spatial variations in aboveground live tree biomass carbon (AGC) stocks remain poorly understood, in particular in tropical montane forests. Because of climatic and soil changes with increasing elevation, AGC stocks are lower in tropical montane compared to lowland forests. Here we ass...

Tropical forests store 40–50 per cent of terrestrial vegetation carbon1. However, spatial variations in aboveground live tree biomass carbon (AGC) stocks remain poorly understood, in particular in tropical montane forests2. Owing to climatic and soil changes with increasing elevation3, AGC stocks are lower in tropical montane forests compared with...

Diversity and community composition of soil microorganisms along the elevation climosequences have been widely studied, while the microbial metabolic potential, particularly in regard to carbon (C) cycling, remains unclear. Here, a metagenomic analysis of C related genes along five elevations ranging from 767 to 4190 m at Mount Kilimanjaro was anal...

Does traditional generalist herbarium collecting record grass diversity more effectively than plot-based recording common in ecology? We present a checklist of the Poaceae of Mount Kilimanjaro compiled from two datasets: records from 1646 plots of 0.1ha each made since the 1990s, as well as all the specimens held at K and NHT herbaria. We record a...

Aim Alpine ecosystems differ in area, macroenvironment and biogeographical history across the Earth, but the relationship between these factors and plant species richness is still unexplored. Here, we assess the global patterns of plant species richness in alpine ecosystems and their association with environmental, geographical and historical facto...

Tropical forests represent the largest store of terrestrial biomass carbon (C) on earth and contribute over-proportionally to global terrestrial net primary productivity (NPP). How climate change is affecting NPP and C allocation to tree components in forests is not well understood. This is true for tropical forests, but particularly for African tr...

Questions What are the functional trade‐offs of vascular plant species in global alpine ecosystems? How is functional variation related to vegetation zones, climatic groups and biogeographic realms? What is the relative contribution of macroclimate and evolutionary history in shaping the functional variation of alpine plant communities? Location G...

Tropical mountains and especially their forests are hot spots of biodiversity threatened by human population pressure and climate change. The diversity of lichens in tropical Africa is especially poorly known. Here we use the mtSSU and nuITS molecular markers together with morphology and ecology to assess Leptogium (Peltigerales, Ascomycota) divers...

The Mt. Kilimanjaro region is known for its long history of intensive agriculture, but the temporal extent of human activity and its impact on the regional ecosystem are not well known. In this study, climate-human-landscape interactions during the past ~2200 years were examined using climate and vegetation proxies extracted from the continuous and...

Aim: Although patterns of biodiversity across the globe are well studied, there is still a controversial debate about the underlying mechanisms and their generality across biogeographic scales. In particular, it is unclear to what extent diversity patterns along environmental gradients are directly driven by abiotic factors, such as climate, or ind...

Evolution is the source of all living organisms and hence the foundation for the ecosystem services that are directly supported by biodiversity. However, explicit connections between evolutionary history and human well-being are barely explored. Here, we focus on ethnobotanical data from Mt. Kilimanjaro (Tanzania) to identify significant associatio...

Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and...

Aim: Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) an...

Microbial elevational diversity patterns have been extensively studied, but their shaping mechanisms remain to be explored. Here, we examined soil bacterial and fungal diversity and community compositions across a 3.4 km elevational gradient (consists of 5 elevations) on Mt. Kilimanjaro located in East Africa. Bacteria and fungi had different diver...

The mobilization of soil nutrients bound in organic matter is largely mediated by enzymes derived from plants, soil microorganisms and animal residues. Land-use change alters important soil characteristics that may affect the activities of soil enzymes. However, mechanistic understanding of how land use and management practices influence the cataly...

Aim: Species differ in their degree of specialization when interacting with other species, with significant consequences for the function and robustness of ecosystems. In order to better estimate such consequences, we need to improve our understanding of the spatial patterns and drivers of specialization in interaction networks. Methods: Here, w...

Fine roots (≤2 mm) consume a large proportion of photosynthates and thus play a key role in the global carbon cycle, but our knowledge about fine root biomass, production, and turnover across environmental gradients is insufficient, especially in tropical ecosystems. Root system studies along elevation transects can produce valuable insights into r...

Research Highlights: Global coffee production, especially in smallholder farming systems, is vulnerable and must adapt in the face of climate change. To this end, shaded agroforestry systems are a promising strategy. Background and Objectives: Understanding local contexts is a prerequisite for designing locally tailored systems; this can be achieve...

Notwithstanding its crucial importance for assessing the vulnerability of tropical mountain ecosystems to both local anthropogenic pressure and climate change, knowledge of the relationships between climate, hydrology and vegetation on Mt. Kilimanjaro is highly fragmentary. Unraveling the pathway of water from precipitation to transpiration can als...

The 150 grassland plots were located in three study regions in Germany, 50 in each region. The dataset describes the yearly grassland management for each grassland plot using 116 variables. General information includes plot identifier, study region and survey year. Additionally, grassland plot characteristics describe the presence and starting year...

Classifying land use/land cover (LULC) with sufficient accuracy in heterogeneous landscapes is challenging using only satellite imagery. To improve classification accuracy inclusion of features from auxiliary geospatial datasets in classification models is applied since 1980s. However, the method is mostly limited to pixel-based classifications, and the...

Tropical mountain ecosystems cover a broad variety of climatic and vegetation zones and are global hotspots of biodiversity. These ecosystems are severely threatened by climate and land-use change, which also strongly affect soil properties. Mt. Kilimanjaro, with its large elevation gradient and relatively homogeneous geology of volcanic rocks and...

Aim Previous studies have shown that phylogenetic divergence (i.e. the average phylogenetic displacement between species in a community) is highly sensitive to the underlying branching patterns of phylogenies, suggesting that there is a need to integrate both facets of phylogenic information to obtain a better understanding of assemblage structure....

Leaf-wax n-alkanes are produced by terrestrial plants, and through long-term preservation in sediments their stable hydrogen-isotopic signature (δ²Hwax) provides useful information on past hydrological variation for paleoclimate reconstructions. However, gaps remain in our understanding of the relationships between the isotopic signatures of leaf w...

Accumulating evidence suggests that species sensitivity to climatic change is strongly related to their ecological niches, which are somewhat evolutionary conserved. Insofar as this is true, climate change-driven extinctions may be non-random with respect to phylogeny, and entire branches of the tree of life might be lost. In mountainous regions, w...

2019, The Author(s), under exclusive licence to Springer Nature Limited. In this Letter, the middle initial of author G. J. Nabuurs was omitted, and he should have been associated with an additional affiliation: ‘Forest Ecology and Forest Management Group, Wageningen University and Research, Wageningen, The Netherlands’ (now added as affiliation 18...

A spatially explicit global map of tree symbioses with nitrogen-fixing bacteria and mycorrhizal fungi reveals that climate variables are the primary drivers of the distribution of different types of symbiosis.

Agriculture and the exploitation of natural resources have transformed tropical mountain ecosystems across the world, and the consequences of these transformations for biodiversity and ecosystem functioning are largely unknown1–3. Conclusions that are derived from studies in non-mountainous areas are not suitable for predicting the effects of land-...

Since the publication of the Checklist and Red List of higher plants of Brandenburg in 2006 numerous changes in the flora of Berlin and Brandenburg have appeared. Some taxa have been newly found or refound, some have got extinct, others have become established, andtheir st atus has to be changed. Aim of this contribution is to indicate and document...

Asplenium arcumontanum (Aspleniaceae), a new terrestrial forest species from northern Tanzania, is described and illustrated. This taxon is closely related to the more widespread A. elliottii, a vicariant species with similar habitat requirements but a near-allopatric distribution. Asplenium arcumontanum fits the typical altitudinal zonation patter...

A phylogeny of the genus Phlesirtes Bolivar is presented, based on new sequence data of three genes (16S rDNA, COI, H3). Species of the genus Phlesirtes (subtribe Karniellina of the Tribe Conocephalini) occupy habitats of montane to afroalpine grasslands in East Africa. Phlesirtes is the most species-rich genus of the subtribe Karniellina, a group...

A phylogeny of the genus Phlesirtes Bolivar is presented, based on new sequence data of three genes (16S rDNA, COI, H3). Species of the genus Phlesirtes (subtribe Karniellina of the Tribe Conocephalini) occupy habitats of montane to afroalpine grasslands in East Africa. Phlesirtes is the most species-rich genus of the subtribe Karniellina, a group...