For all researches, please visit our "Peer-reviewed publications" page.
Bellard C, Genovesi P, Jeschke J (2016)
Proceedings of the Royal Society B: Biological Sciences 283(1823) 20152454.
Biological invasions as drivers of biodiversity loss have recently been challenged. Fundamentally, we must know where species that are threatened by invasive alien species (IAS) live, and the degree to which they are threatened. We report the first study linking 1372 vertebrates threatened by more than 200 IAS from the completely revised Global Invasive Species Database. New maps of the vulnerability of threatened vertebrates to IAS permit assessments of whether IAS have a major influence on biodiversity, and if so, which taxonomic groups are threatened and where they are threatened. We found that centres of IAS-threatened vertebrates are concentrated in the Americas, India, Indonesia, Australia and New Zealand. The areas in which IAS-threatened species are located do not fully match the current hotspots of invasions, or the current hotspots of threatened species. The relative importance of biological invasions as drivers of biodiversity loss clearly varies across regions and taxa, and changes over time, with mammals from India, Indonesia, Australia and Europe are increasingly being threatened by IAS. The chytrid fungus primarily threatens amphibians, whereas invasive mammals primarily threaten other vertebrates. The differences in IAS threats between regions and taxa can help efficiently target IAS, which is essential for achieving the Strategic Plan 2020 of the Convention on Biological Diversity.
Biber-Freudenberger L, Ziemacki J, Tonnang H, Borgemeister C (2016)
PloS one 11(4) e0153237.
Most agricultural pests are poikilothermic species expected to respond to climate change. Currently, they are a tremendous burden because of the high losses they inflict on crops and livestock. Smallholder farmers in developing countries of Africa are likely to suffer more under these changes than farmers in the developed world because more severe climatic changes are projected in these areas. African countries further have a lower ability to cope with impacts of climate change through the lack of suitable adapted management strategies and financial constraints. In this study we are predicting current and future habitat suitability under changing climatic conditions for Tuta absoluta, Ceratitis cosyra, and Bactrocera invadens, three important insect pests that are common across some parts of Africa and responsible for immense agricultural losses. We use presence records from different sources and bioclimatic variables to predict their habitat suitability using the maximum entropy modelling approach. We find that habitat suitability for B. invadens, C. cosyra and T. absoluta is partially increasing across the continent, especially in those areas already overlapping with or close to most suitable sites under current climate conditions. Assuming a habitat suitability at three different threshold levels we assessed where each species is likely to be present under future climatic conditions and if this is likely to have an impact on productive agricultural areas. Our results can be used by African policy makers, extensionists and farmers for agricultural adaptation measures to cope with the impacts of climate change.
Bocksberger G, Schnitzler J, Chatelain C, Daget P, Janssen T, Schmidt M et al. (2016)
Journal of Vegetation Science.
Questions Which environmental variables influence grass diversity in West Africa? What are the effects of climate and grass functional traits on the spatial patterns (richness and abundance) of the grass clades Andropogoneae, Paniceae and Chloridoideae? Location West Africa, demarcated by the Atlantic Ocean in the west and south (20° W and 4° N), the Sahara desert in the north (25° N) and the border between Niger and Chad in the east (20° E). Methods Based on 38 912 georeferenced occurrence records, we modelled the distribution of 302 grass species (51% of West African grass diversity). We integrated species richness, abundance and functional traits (life cycle, photosynthetic type and height) to determine the contribution of the most speciose grass clades (Andropogoneae, Paniceae and Chloridoideae) to overall grass diversity in West Africa. Results Precipitation is the variable most often influencing the species distribution models of grasses in West Africa. Richness and relative abundance of the tribe Andropogoneae show a centre of diversity in Sudanian savanna regions. The height of Andropogoneae species, generally >150 cm, is driving this ecological dominance. Species richness of the tribe Paniceae is more dispersed and shows two main centres of abundance: The southern regions with higher mean annual precipitation and tree density are dominated by C3 Paniceae species. The Sahelian regions in the north are dominated by short Paniceae species with the C4 NAD-ME photosynthetic subtype, as well as Chloridoideae possessing the same functional attributes. Conclusions Our study provides insight into the environmental correlates of grass species richness in West Africa and contributes to the much-needed research on tropical rangelands. Moreover, the integration of evolutionary history significantly improves our understanding of large-scale biodiversity patterns.
Keywords: Andropogoneae, Chloridoideae, Maxent, Paniceae, Poaceae, Savanna, Species distribution modelling, West Africa, species richness
Duan R, Kong X, Huang M, Varela S, Ji X (2016)
The potential effects of climate change on amphibian distribution, range fragmentation and turnover in China
Many studies predict that climate change will cause species movement and turnover, but few studies have considered the effect of climate change on range fragmentation for current species and/or populations. We used MaxEnt to predict suitable habitat, fragmentation and turnover for 134 amphibian species in China under 40 future climate change scenarios spanning four pathways (RCP2.6, RCP4.5, RCP6 and RCP8.5) and two time periods (the 2050s and 2070s). Our results show that climate change will cause a major shift in the spatial patterns of amphibian diversity. Suitable habitats for over 90% of species will be located in the north of the current range, for over 95% of species in higher altitudes, and for over 75% of species in the west of the current range. The distributions of species predicted to move westwards, southwards and to higher altitudes will contract, while the ranges of the species not showing these trends will expand. Amphibians will lose 20% of their original ranges on average; the distribution outside current ranges will increase by 15%. Climate change will likely modify the spatial configuration of climatically suitable areas. Changes in area and fragmentation of climatically suitable patches are related, which means that species may be simultaneously affected by different stressors as a consequence of climate change.
Keywords: Amphibians, Climate impacts, Dispersal, Distribution, Fragmentation, MaxEnt, Range shifts, Turnover
Dufresnes C, Litvinchuk S, Leuenberger J, Ghali K, Zinenko O, Stöck M et al. (2016)
Evolutionary melting pots: a biodiversity hotspot shaped by ring diversifications around the Black Sea in the Eastern tree frog ( Hyla orientalis )
Hotspots of intraspecific genetic diversity, which are of primary importance for the conservation of species, have been associated to glacial refugia, i.e. areas where species survived the Quaternary climatic oscillations. However, the proximate mechanisms generating these hotspots remain an open issue. Hotspots may reflect the long-term persistence of large refugial populations; alternatively, they may result from allopatric differentiation between small and isolated populations, that later admixed. Here we test these two scenarios in a widely distributed species of tree frog, Hyla orientalis, which inhabits Asia Minor and Southeastern Europe. We apply a fine-scale phylogeographic survey, combining fast-evolving mitochondrial and nuclear markers, with a dense sampling throughout the range, as well as ecological niche modeling, to understand what shaped the genetic variation of this species. We documented an important diversity center around the Black Sea, composed of multiple allopatric and/or parapatric diversifications, likely driven by a combination of Pleistocene climatic fluctuations and complex regional topography. Remarkably, this diversification forms a ring around the Black Sea, from the Caucasus through Anatolia and Eastern Europe, with terminal forms coming into contact and partially admixing in Crimea. Our results support the view that glacial refugia generate rather than host genetic diversity, and can also function as evolutionary melting pots of biodiversity. Moreover, we report a new case of ring diversification, triggered by a large, yet cohesive dispersal barrier, a very rare situation in nature. Finally, we emphasize the Black Sea region as an important center of intraspecific diversity in the Palearctic with implications for conservation.
Keywords: Amphibians, Climate impacts, Dispersal, Distribution, Fragmentation, MaxEnt, Range shifts, Turnover
Herkt K, Barnikel G, Skidmore A, Fahr J (2016)
Ecological Modelling 320 9-28.
Bats are the second-most species-rich mammal group numbering more than 1270 species globally. Our knowledge of their geographic distributions and diversity patterns however is very limited – possibly the poorest among mammals – mainly due to their nocturnal and volant life history, and challenging fieldwork conditions in the tropics where most bat species occur. This knowledge gap obscures the geographic extent of ecosystem services provided by bats (i.e. pollination, seed dispersal and insect control), translates into inefficient conservation policies, and restricts macroecological analyses to coarse spatial resolutions. In contrast to the currently prevailing method of estimating species distributions using expert-drawn range maps, correlative species distribution models (SDMs) can provide estimates at very fine spatial grains and largely account for widespread sample bias as well as the prevalent Wallacean shortfall in species occurrence data. Very few such studies have hitherto been published that cover a large and complete taxonomic group with fine resolution at continental extent. Using an unparalleled amount of occurrence data, the MaxEnt algorithm and tailored solutions to specific modelling challenges, we created SDMs for nearly all 250 African bat species to explore emerging diversity patterns at a resolution of 1km2. Predicted species richness generally increases towards the equator conforming to expectations. Within the tropical area of elevated richness, several pronounced richness peaks and lows stand out, hinting at a complex interplay of determining factors. Richness gradients are often steep, decreasing strongly away from streams, and especially so in savanna biomes. Species richness also seems positively associated with rugged terrain, in particular at lower elevations. Centres of endemism are found primarily at low latitudes near major elevational ranges. Overlap with hotspots of species richness is rather low, and confined to five or six topodiverse, relatively low lying areas between western Guinea and the East African coast. Several poorly sampled regions are identified that may represent rewarding future survey targets. Our results demonstrate the value of stacking SDMs to infer plausible continent-wide diversity gradients at a spatial resolution fine enough to directly inform conservation policies and to open up new avenues in macroecological research.
Keywords: Africa, Chiroptera, Range size rarity, Spatial resolution, Species distribution modelling (SDM), Species richness
Jia S, Zhang M, Raab-Straube E, Thulin M (2016)
Evolutionary history of Gymnocarpos (Caryophyllaceae) in the arid regions from North Africa to Central Asia
Biological Journal of the Linnean Society.
Gymnocarpos has only about ten species distributed in the arid regions of Asia and Africa, but it exhibits a geographical disjunction between eastern Central Asia and western North Africa and Minor Asia. We sampled eight species of the genus and sequenced two chloroplast regions (rps16 and psbB–psbH), and the nuclear rDNA (ITS) to study the phylogeny and biogeography. The results of the phylogenetic analyses corroborated that Gymnocarpos is monophyletic, in the phylogenetic tree two well supported clades are recognized: clade 1 includes Gymnocarpos sclerocephalus and G. decandrus, mainly the North African group, whereas clade 2 comprises the remaining species, mainly in the Southern Arabian Peninsula. Molecular dating analysis revealed that the divergence age of Gymnocarpos was c. 31.33 Mya near the Eocene and Oligocene transition boundary, the initial diversification within Gymnocarpos dated to c. 6.69 Mya in the late Miocene, and the intraspecific diversification mostly occurred during the Quaternary climate oscillations. Ancestral area reconstruction suggested that the Southern Arabian Peninsula was the ancestral area for Gymnocarpos. Our conclusions revealed that the aridification since mid-late Miocene significantly affected the diversification of the genus in these areas.
Keywords: 2016, CN, China, DE, GBIF_used, Germany, SE, Sweden, phylogenetic analysis, phylogenetics
Kratochwil A (2016)
Stuttgarter Beiträge zur Naturkunde A 9(1) 217-227.
Nur eine Art unter den apoiden Hymenopteren ist in Island heimisch: Bombus jonellus (Kirby, 1802). Eine zweite Art, Andrena tarsata Nylander, 1848, wurde von Schmiedeknecht (1882–1884) erwähnt; ihr Vorkommen erscheint sehr zweifelhaft. Vier Hummelarten wurden bisher eingeführt: B. hortorum (Linnaeus, 1761), erster Nachweis 1959; B. lucorum (Linnaeus, 1761), erster Nachweis 1979; B. hypnorum (Linnaeus, 1758) und B. pascuorum (Scopoli, 1763), erste Nachweise 2010. Ferner wird B. terrestris (Linnaeus, 1761) zur Bestäubung von Tomaten in Gewächshäusern in Island eingesetzt (seit 2002). Beobachtungen im Jahr 2014 erbrachten das Ergebnis einer starken Ausbreitung von B. lucorum besonders im Nordosten Islands. Die heutige Verbreitung aller in Island vorkommenden Hummelarten wird vorgestellt und Angaben über ihren taxonomischen Status, Habitat-Präferenzen, besondere Anpassungen und Besiedlungsgeschichte angeführt. Über eine vergleichende Analyse wird die zukünftige Entwicklung diskutiert. Die Auswirkungen der globalen Erderwärmung sollten B. jonellus zurückdrängen und einzelne eingeführte Bombus-Arten fördern. B. lucorum wird sich weiter ausbreiten (sowohl außerhalb des Bereichs der Siedlungen und des kultivierten Gebietes als auch innerhalb). B. hortorum ist auf Siedlungsgebiete mit Gärten beschränkt (Bevorzugung tiefkroniger Blüten). Jedoch wird B. lucorum mit B. hortorum um Nektarquellen stark konkurrieren. B. hypnorum ist aufgrund seines spezifischen Nistverhaltens ebenfalls weitgehend auf Siedlungsgebiete beschränkt. Die weitere Entwicklung von B. pascuorum wird wahrscheinlich ebenfalls durch die Effekte der globalen Erwärmung und die höhere Wettbewerbsfähigkeit positiv beeinflusst werden. B. terrestris kann außerhalb von Gewächshäusern in Island derzeit langzeitig nicht überleben.
Keywords: Andrena, Bombus, Iceland, flower visits, global warming, introduced species
Krehenwinkel H, Graze M, Rödder D, Tanaka K, Baba Y, Muster C et al. (2016)
A phylogeographical survey of a highly dispersive spider reveals eastern Asia as a major glacial refugium for Palaearctic fauna
Journal of Biogeography.
Aim The phylogeographical history of wide-ranging Palaearctic species is not well understood. Here, we present a range-wide phylogeographical study of the wasp spider, Argiope bruennichi (Scopoli, 1772), a highly dispersive and widely distributed Palaearctic species. We aim to identify glacial refugia and patterns of interglacial gene flow across the Palaearctic. Location Palaearctic region, including the Azores, Madeira, Europe, North Africa and Asia. Methods We conduct a range-wide phylogeographical survey. Our study is based on nuclear and mitochondrial DNA markers, as well as morphological characters. We use species distribution models to predict the species’ current range as well as its historical distribution during and shortly after the Last Glacial Maximum (LGM). Results All analysed genetic markers and morphological characters support the divergence of a lineage in eastern Asia from the remainder of the Palaearctic. Within the Western Palaearctic, a less pronounced divergence into an Azorean and a European clade is found. Species distribution models predict a pronounced loss of suitable habitat for Western Palaearctic lineages during the LGM, whereas the range of East Asian populations remained largely unaffected. Main conclusions Our results highlight the existence of non-European glacial refugia for Palaearctic species, particularly in East Asia. The current genetic structure is best explained by the recent recolonization of the Western Palaearctic from eastern Asia, or repeated interglacial contact of populations.
Keywords: Azores, East Asia, Madeira, Palaearctic, gene flow, mitochondrial–nuclear incongruence, morphometry, palaeoclimate, phylogeography, species distribution model
Krehenwinkel H, Rödder D, Năpăruş-Aljančič M, Kuntner M (2016)
Rapid genetic and ecological differentiation during the northern range expansion of the venomous yellow sac spider Cheiracanthium punctorium in Europe
Although poleward range expansions are commonly attributed to global change, a complex interaction of ecological and evolutionary factors might contribute to expansion success. Here, we study the expansion of the yellow sac spider Cheiracanthium punctorium, a medically important species in Central Europe. Using microsatellite markers and DNA sequences, morphological and climate niche analyses, we identify factors associated with the spider's expansion success. Our results indicate that the species’ initial expansion has been triggered by environmental change and preadaptation in the source populations. However, despite extensive gene flow, expanding populations maintain genetic and morphological differentiation from native ones, which is correlated with climatic niche differences. Moreover, expanding spiders might have temporarily escaped an eggsac parasite that causes high mortality in the native range. Hence, our results paint a complex picture of diverse factors associated with expansion success. We speculate that expanding populations might be capable of adapting to novel ecological conditions in Northern Europe. This could allow a substantial range expansion, much farther than by environmental change alone. Our distribution model predicts that the spider will soon massively spread over most of Northern Europe, bringing along considerable health concerns.
Keywords: Range expansion, adaptation, global change, isolation by environment, venomous spider