Browsing by Author "Schaefer, Hanno"
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- Bees of the Azores : an annotated checklist (Apidae, Hymenoptera)Publication . Weissmann, Julie A.; Picanço, Ana; Borges, Paulo A. V.; Schaefer, HannoWe report 18 species of wild bees plus the domesticated honeybee from the Azores, which adds nine species to earlier lists. One species, Hylaeus azorae, seems to be a single island endemic, and three species are possibly native (Colletes eous, Halictus villosulus, and Hylaeus pictipes). All the remaining bee species are most likely accidental introductions that arrived after human colonization of the archipelago in the 15th century. Bee diversity in the Azores is similar to bee diversity of Madeira and Cape Verde but nearly ten times lower than it is in the Canary Islands.
- Dispersal syndromes are poorly associated with climatic niche differences in the Azorean seed plantsPublication . Leo, María; Steinbauer, Manuel J.; Borges, Paulo A. V.; Azevedo, Eduardo B.; Gabriel, Rosalina; Schaefer, Hanno; Santos, Ana M.C.AIM: Environmental niche tracking is linked to the species ability to disperse. While well investigated on large spatial scales, dispersal constraints also influence small-scale processes and may explain the difference between the potential and the realized niche of species at small scales. Here we test whether niche size and niche fill differ systematically according to dispersal syndrome within isolated oceanic islands. We expect that species with higher dispersal abilities (anemochorous or endozoochorous) will have a higher niche fill, despite their environmental niche size. LOCATION: Azores archipelago. TAXON: Native seed plants. METHODS: We combined a georeferenced database of the species distribution within the archipelago (Azorean Biodiversity Portal/GBIF) with an expert-based dispersal syndrome categorization and a high-resolution climatic grid (CIELO model). Using four climatic variables (Annual Mean Temperature, Mean Diurnal Range, Annual Precipitation, Precipitation Seasonality), we calculated a four-dimensional hypervolume to estimate the niche size of each species. Niche fill was quantified as the suitable climatic space of the island that was occupied by the focal species. RESULTS: We found a significant relationship between dispersal syndromes and niche size, and also between dispersal syndromes and niche fill. Such relationships presented no phylogenetic signal. Endozoochorous species display higher niche fill compared to epizoochorous and hydrochorous species, and larger niches than anemochorous and epizoochorous. Differences among the remaining groups are not significant for either niche size or for niche fill. MAIN CONCLUSIONS: The ability of a species to track its niche at small scales is not tightly related to its dispersal syndrome, although endozoochorous species track their niche more efficiently than the rest of groups. Despite being intuitively appealing, dispersal syndrome classifications might not be the most appropriate tools for understanding dispersal processes at small scales.
- Honeybees (Apis mellifera) collect latex of Azores bellflowers (Azorina vidalii, Campanulaceae)Publication . Weissmann, Julie A.; Schaefer, HannoThe Azores bellflower (Azorina vidalii (H.C.Wats.) Feer, synonym: Campanula vidalii H.C.Wats.) is a small shrub in the bellflower family, Campanulaceae, which is endemic to the Azores archipelago. Its habitats are coastal rocks and cliffs, often with elevated nitrogen levels (sewage water, rubbish) and close to settlements. Azorina is found on all nine islands of the Azores archipelago but is most common on the western islands of Flores and Corvo (Schaefer 2003). The pollination biology of Azorina is still a bit of a mystery: while flower morphology would fit best to bird pollination, birds have never been observed visiting its flowers and today’s avifauna of the archipelago does not include any obvious candidate species. The first author therefore performed an extensive field study in the summer of 2015, mainly on Corvo but also on Flores and Pico islands, in order to identify the pollinators of this enigmatic endemic. […].
- The importance of generalist pollinator complexes for endangered island endemic plantsPublication . Weissmann, Julie A.; Schaefer, HannoTo investigate whether endangered endemic plants of the Azores are threatened by pollinator limitation, we studied the insect pollinator communities of Azorina vidalii, Euphrasia azorica, Myosotis azorica and Solidago azorica on Corvo Island. We found no evidence for dependence on a specialised pollinator. Instead, we found five to 21 mostly generalist insect pollinators per plant species, six of them probably introduced species. Diptera, with at least 12 species, and Hymenoptera, with at least nine species, are the most important insect orders and also most important in visitation frequency. The relatively high pollinator diversity for each of the studied plants and the high proportion of generalists indicate that the pollination networks of the four study plant species are rather resilient, i.e. the loss of a species would not constitute an immediate threat. Seed counts and numbers of juvenile plants indicate that reproductive success of all four species is stable. Altogether, our results suggest that there is no pollinator limitation in the four study species. Conservation measures should therefore focus on other threats, on Corvo mainly on grazing pressure.
- Is there solid evidence of widespread landscape disturbance in the Azores before the arrival of the Portuguese?Publication . Elias, Rui B.; Connor, Simon; Góis-Marques, Carlos A.; Schaefer, Hanno; Silva, Luís; Sequeira, Miguel M.; Moura, Mónica; Borges, Paulo A. V.; Gabriel, RosalinaRaposeiro et al. conclude that human occupation of the Azores islands began between 700 and 850 CE, causing widespread landscape disturbance and raising doubts about the islands’ presumed pristine nature when the Portuguese arrived. However, previous paleoecological studies from Flores, Pico, and Sao Miguel Islands (Table 1) show that permanent changes in the vegetation occurred only after the early 15th century. The authors’ work also shows the permanent decline, to the lowest levels, in arboreal pollen on Corvo and Flores occurring during Portuguese occupation, not before. […].
- Macaronesia as a Fruitful Arena for Ecology, Evolution, and Conservation BiologyPublication . Florencio, Margarita; Patiño, Jairo; Nogué, Sandra; Traveset, Anna; Borges, Paulo A. V.; Schaefer, Hanno; Amorim, Isabel R.; Arnedo, Miquel A.; Ávila, Sérgio P.; Cardoso, Pedro; Nascimento, Lea; Fernández-Palacios, José María; Gabriel, Sofia I.; Gil, Artur José Freire; Gonçalves, Vitor; Haroun, Ricardo J.; Illera, Juan Carlos; López-Darias, Marta; Martínez, Alejandro; Martins, Gustavo M.; Neto, Ana I.; Nogales, Manuel; Oromí, Pedro; Rando, Juan Carlos; Raposeiro, Pedro M.; Rigal, François; Romeiras, Maria M.; Silva, Luís; Valido, Alfredo; Vanderpoorten, Alain; Vasconcelos, Raquel; Santos, Ana M. C.Research in Macaronesia has led to substantial advances in ecology, evolution and conservation biology. We review the scientific developments achieved in this region, and outline promising research avenues enhancing conservation. Some of these discoveries indicate that the Macaronesian flora and fauna are composed of rather young lineages, not Tertiary relicts, predominantly of European origin. Macaronesia also seems to be an important source region for back-colonisation of continental fringe regions on both sides of the Atlantic. This group of archipelagos (Azores, Madeira, Selvagens, Canary Islands, and Cabo Verde) has been crucial to learn about the particularities of macroecological patterns and interaction networks on islands, providing evidence for the development of the General Dynamic Model of oceanic island biogeography and subsequent updates. However, in addition to exceptionally high richness of endemic species, Macaronesia is also home to a growing number of threatened species, along with invasive alien plants and animals. Several innovative conservation and management actions are in place to protect its biodiversity from these and other drivers of global change. The Macaronesian Islands are a well-suited field of study for island ecology and evolution research, mostly due to its special geological layout with 40 islands grouped within five archipelagos differing in geological age, climate and isolation. A large amount of data is now available for several groups of organisms on and around many of these islands. However, continued efforts should be made toward compiling new information on their biodiversity, to pursue various fruitful research avenues and develop appropriate conservation management tools.
- Original plant diversity and ecosystems of a small, remote oceanic island (Corvo, Azores): Implications for biodiversity conservationPublication . Connor, Simon E.; Lewis, Tara; van Leeuwen, Jacqueline F.N.; van der Knaap, W.O. (Pim); Schaefer, Hanno; Porch, Nicholas; Gomes, Ana I.; Piva, Stephen B.; Gadd, Patricia; Kuneš, Petr; Haberle, Simon G.; Adeleye, Matthew; Mariani, Michela; Elias, Rui B.Remote islands harbour many endemic species and unique ecosystems. They are also some of the world's most human-impacted systems. It is essential to understand how island species and ecosystems behaved prior to major anthropogenic disruption as a basis for their conservation. This research aims to reconstruct the original, pre-colonial biodiversity of a remote oceanic island to understand the scale of past extinctions, vegetation changes and biodiversity knowledge gaps. We studied fossil remains from the North Atlantic island of Corvo (Azores), including pollen, charcoal, plant macrofossils, diatoms and geochemistry of wetland sediments from the central crater of the island, Caldeirão. A comprehensive list of current vascular plant species was compiled, along with a translation table comparing fossilized pollen to plant species and a framework for identifying extinctions and misclassifications. Pollen and macrofossils provide evidence for eight local extinctions from the island's flora and show that four species listed as ‘introduced’ are native. Up to 23 % of the pollen taxa represent extinct/misclassified species. Corvo's past environment was dynamic, shifting from glacial-era open vegetation to various Holocene forest communities, then almost completely deforested by fires, erosion and grazing following Portuguese colonisation. Historical human impacts explain high ecological turnover, several unrecorded extinctions and the present-day abundance of vegetation types like Sphagnum blanket mire. We use Corvo as a case study on how fossil inventories can address the Wallacean and Hookerian biodiversity knowledge gaps on remote islands. Accurate baselines allow stakeholders to make informed conservation decisions using limited financial and human resources, particularly on islands where profound anthropogenic disruption occurred before comprehensive ecological research.
- Putting biogeography's cart back behind taxonomy's horse: a response to Triantis et al.Publication . Carine, Mark A.; Jones, Katy; Moura, Mónica; Maciel, Graciete Belo; Rumsey, Fred J.; Schaefer, HannoIn a recent paper, two of us discussed diversity patterns and diversification processes in the Azores flora. Triantis et al. (2012, Journal of Biogeography, 39, 1179-1184) challenged our hypothesis that palaeoclimatic differences had an effect on diversification rates and suggested that area, island age and isolation explain diversity patterns. They did not, however, fully address the results from our subsequent paper, in which we showed that diversity patterns evident from phylogeographic studies differ markedly from those suggested by checklists. Checklists are working hypotheses and we suggest that the discrepancies evident between molecular data and checklists may be indicative of deficiencies in our taxonomic understanding of the Azores flora. Patterns of molecular and morphological diversity need to be better understood, and the discrepancies between checklists and molecular data accounted for, before we can establish the relative importance of factors such as palaeoclimate, area, island age or isolation in generating endemic diversity patterns in the Azores flora.