The rocky shores of the north-east Atlantic have been long studied. Our focus is from Gibraltar to Norway plus the Azores and Iceland. Phylogeographic processes shape biogeographic patterns of biodiversity. Long-term and broadscale studies have shown the responses of biota to past climate fluctuations and more recent anthropogenic climate change. Inter- and intra-specific species interactions along sharp local environmental gradients shape distributions and community structure and hence ecosystem functioning. Shifts in domination by fucoids in shelter to barnacles/mussels in exposure are mediated by grazing by patellid limpets. Further south fucoids become increasingly rare, with species disappearing or restricted to estuarine refuges, caused by greater desiccation and grazing pressure. Mesoscale processes influence bottom-up nutrient forcing and larval supply, hence affecting species abundance and distribution, and can be proximate factors setting range edges (e.g., the English Channel, the Iberian Peninsula). Impacts of invasive non-native species are reviewed. Knowledge gaps such as the work on rockpools and host–parasite dynamics are also outlined.
Ground squirrels of the genus Marmota are known for their ability to tolerate bitterly cold climates, which they in part accomplish with their exceptional ability to hibernate for as much as eight months a year (Armitage et al., 2003). Most of the 15 living species are associated with montane habitats, and those that are not, like the North American woodchuck (Marmota monax) and the eastern European and central Asian bobak (M. bobak) inhabit regions with strongly seasonal climates and often bitterly cold winters (Armitage, 2000) (Figure 9.1). All marmots construct burrows, which can be more than one metre deep even in comparatively mild climates and as much as seven metres deep in the harsh climates of the Himalayas (Barash, 1989). During the cold phases of the last half of the Quaternary the fossil record demonstrates many marmots inhabited periglacial environments (Zimina and Gerasimov, 1973; Kalthoff, 1999). For these reasons, marmots are sometimes considered to be a quintessentially Quaternary clade, specialists on the cold variable climates that are unique to the past 2.6 million years of Earth's history. The world in which they originated, however, was very different; a warmer one in which there were no tundra biomes, no glacial–interglacial cycles, and no permanent ice cover in the Northern Hemisphere. In this chapter, we review the fossil and phylogenetic history of marmots, the palaeoenvironments in which they originated, and their relationship to glacial–interglacial cycles to better understand the contexts in which the specializations of this unique clade of rodents arose.
The Quaternary, the current geological period, is defined by the onset of permanent ice sheets in the Northern Hemisphere 2.58 million years ago and is by far the coldest period since the extinction of the last non-avian dinosaurs 65 million years ago (Zachos et al., 2001; Gibbard et al., 2010).
Potato is South America's greatest gift to world agriculture and human nutrition (Graves, 2001). A dietary staple of indigenous Andean peoples for eight millennia, potato was unknown to the rest of the world before the mid sixteenth century. Today, potato is the world's fourth most important food crop, after maize, wheat and rice, and is grown on a significant scale in more than 130 countries on six continents with annual tuber production exceeding 320 million tonnes (Food and Agriculture Organization, 2007). In recognition of potato's potential to provide food security and eradicate poverty, 2008 has been proclaimed International Year of the Potato.
In most production systems, potato is clonally propagated from “seed” tubers. Clonal propagation offers agronomic and genetic advantages, e.g. vigorous early growth, higher yields and consistent expression of desirable traits. More than 10% of world potato production is used to provide “seed tubers” for planting the next production season. Seed potato tubers can be infected with a wide range of pests and pathogens which may affect growth of the crop and health of progeny tubers. Thus, access to high-quality, disease-free seed potatoes has been described as “the single most important integrated pest management practice available to potato growers” (Gutbrod & Mosley, 2001). Seed potato lots can be downgraded or rejected for recertification for myriad causes from “varietal mix” to herbicide injury. However, aphid-transmitted, tuber-borne potato viruses far exceed all others.
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