35 research outputs found
Climate-driven range extension of Amphistegina (protista, foraminiferida) : models of current and predicted future ranges
© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS ONE 8 (2013): e54443, doi:10.1371/journal.pone.0054443.Species-range expansions are a predicted and realized consequence of global climate change. Climate warming and the poleward widening of the tropical belt have induced range shifts in a variety of marine and terrestrial species. Range expansions may have broad implications on native biota and ecosystem functioning as shifting species may perturb recipient communities. Larger symbiont-bearing foraminifera constitute ubiquitous and prominent components of shallow water ecosystems, and range shifts of these important protists are likely to trigger changes in ecosystem functioning. We have used historical and newly acquired occurrence records to compute current range shifts of Amphistegina spp., a larger symbiont-bearing foraminifera, along the eastern coastline of Africa and compare them to analogous range shifts currently observed in the Mediterranean Sea. The study provides new evidence that amphisteginid foraminifera are rapidly progressing southwestward, closely approaching Port Edward (South Africa) at 31°S. To project future species distributions, we applied a species distribution model (SDM) based on ecological niche constraints of current distribution ranges. Our model indicates that further warming is likely to cause a continued range extension, and predicts dispersal along nearly the entire southeastern coast of Africa. The average rates of amphisteginid range shift were computed between 8 and 2.7 km year−1, and are projected to lead to a total southward range expansion of 267 km, or 2.4° latitude, in the year 2100. Our results corroborate findings from the fossil record that some larger symbiont-bearing foraminifera cope well with rising water temperatures and are beneficiaries of global climate change.This work was supported by grants from the German Science Foundation (DFG; www.dfg.de) to ML and SL (LA 884/10-1, LA 884/5-1)
Speleothem and glacier records of latest Pleistocene–early Holocene climate change in the western North American interior
Eruption dynamics at Pahvant Butte volcano, Utah, western USA: insights from ash-sheet dispersal, grain size, and geochemical data
Orbital control of western North America atmospheric circulation and climate over two glacial cycles
Slip rate variations on normal faults during glacial–interglacial changes in surface loads
International Entrepreneurship and Geographic Location: An Empirical Examination of New Venture Internationalization
Slip rate variations on normal faults during glacial–interglacial changes in surface loads
International entrepreneurship and geographic location: an empirical examination of new venture internationalization
The export orientation and export performance of high-technology SMEs in emerging markets: the effects of knowledge transfer by returnee entrepreneurs
Combining international business research with the knowledge-based view,
this paper examines factors affecting the export orientation and export
performance of high-technology Small and medium enterprises (SMEs) in an
emerging economy. Using a unique, hand-collected dataset of 711 SMEs from
Zhongguancun Science Park in China, it argues that export orientation and
performance depend not only on the development of capabilities through R&D
and technology transfer, but also on entrepreneurial characteristics, such as the
founder’s international background and global networks. It is also shown that
both export orientation and performance are positively associated with the
presence of a ‘‘returnee’’ entrepreneur