Selection of candidate coding DNA barcoding regions for use on land plants

An in silico screen of 41 of the 81 coding regions of the Nicotiana plastid genome generated a shortlist of 12 candidates as DNA barcoding loci for land plants. These loci were evaluated for amplification and sequence variation against a reference set of 98 land plant taxa. The deployment of multiple primers and a modified multiplexed tandem polymerase chain reaction yielded 85–94% amplification across taxa, and mean sequence differences between sister taxa of 6.1 from 156 bases of accD to 22 from 493 bases of matK. We conclude that loci should be combined for effective diagnosis, and recommend further investigation of the following six loci: matK, rpoB, rpoC1, ndhJ, ycf5 and accD. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 1–11.     

Microhabitat as a determinant of diversity: stream invertebrates colonizing leaf packs

1. Macroinvertebrate colonization of artificial leaf packs of differing palatability to detritivores was measured in a low-order stream. 2. The most palatable leaf types—alder and young beech—were colonized mainly by detritivores and consumed rapidly, so that species diversity on the substrate remained low. In the case of the less palatable old beech and paper ‘leaves’, however, colonization was slower but species diversity approached that of the surrounding benthos. 3. After 1 week, species diversity in paper ‘leaf packs was equivalent to that of the benthos, but species composition was dissimilar. 4. I argue that species diversity of a patch of stream bed may be inversely related to the abundance or palatability of a given food resource, and that this relationship is maintained by the instability of the stream bed habitat, precluding a long-term community response to increased food availability. It may be, however, that the dispersal abilities of many aquatic insects allow a rapid response to the creation of novel habitats.     

Late Holocene flooding in the Ecuadorian rain forest

SUMMARY 1. The stratigraphy, radiocarbon chronology, sedimentary pigment, and cation records of sediment cores from four lakes in the Ecuadorian rain forest show that regional flooding occurred from about 1300 to 800 'BP. Each core contains a stratum of alluvial clay, silt and sand overlain by lacustrine deposits of peat, gyttja or clayey gyttja. Radiocarbon dates show that the onset and termination of the alluvial event was synchronous across the sites. Short-term, possibly regional, flooding occurred at each of the sites at least once since the major flood.
2. A core from Anangucocha, a black-water lake, records the geoche- mical signature of white-water incursion during this flooding interval. Sedimentary pigments show that aquatic production at Anañgucocha was low during the lotic interval but rose sharply and remained high within the modern lake period.
3. The Amazon's dynamic river system may have been an important force in promoting and maintaining high floral and faunal diversity.     

Population genetic structure of the winter moth,Operophtera brumata Linnaeus,in the Orkney Isles suggests long‐distance dispersal

1. The application of population genetic analysis and molecular ecological approaches allows us to examine the invasion of species in the wild. In particular, we can gain an insight into the role of dispersal, a key determinant of the invasion and population dynamics of important pest species. Since the 1980s, severe outbreaks of the winter moth, Operophtera brumata (Linnaeus), have caused extensive damage to heather moorlands in the Orkney Isles. The population genetic structure of O. brumata in Orkney was examined in order to establish whether the widely dispersed outbreaking populations are connected. 2. Amplified fragment length polymorphism (AFLP) analysis showed a high level of genetic diversity within subpopulations. This is consistent with an initial mass colonisation event and/or continuing dispersal between populations of O. brumata in Orkney. 3. Genetic differentiation among populations is low, and although some weak isolation by distance is detectable, no effect of isolation as a result of a sea barrier was found. High gene flow between populations is consistent with the low genetic differentiation observed, although there is evidence to suggest that the populations are not panmictic. 4. Given the limited dispersal of adults, the present results suggest that larvae may disperse over considerable distances by ballooning on strong winds across the Orkney Isles.     

Factors affecting habitat selection in a specialist fossorial skink

Habitat specialists maximize their fitness by using a subset of the habitats that are potentially available to them and fare poorly if they move elsewhere. The factors that constrain habitat use are diverse and often difficult to identify, but are important to distinguish if we are to understand the trade-offs that drive species to become specialists. In the present study, we investigated habitat use in a fossorial skink, Lerista labialis , and explore the factors that confine it to the crests of sand dunes in the Simpson Desert, central Australia. Models positing that L. labialis selects dune crests because of their sparse cover of vegetation, more favourable temperatures, and greater abundance of preferred prey, received no support. Instead, a model positing that dune crests provide soft and less compacted sand that facilitates movement by L. labialis , was strongly supported. Sand on the crests was consistently softer that that on the sides and swales of the dunes; the skinks preferred soft rather than hard sand for movement in captivity, and were captured more often on experimentally softened sand than on compacted sand in the field. There was no evidence that L. labialis responds to attributes of the substrate other than softness because captive animals used loose sand from the dune crests, sides, and swales equally. We suggest that the dune crest environment allows L. labialis to reduce the energetic costs of locomotion, provides priority of access to the subterranean galleries of its termite prey, and also a secure refuge from surface-active predators and extreme surface temperatures.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 531–544.