Genetic diversity patterns in Curcuma reflect differences in genome size

The relationships between genome size and the systematic and evolutionary patterns in vascular plants are equivocal, although a close relationship between genome size and evolutionary patterns has been previously reported. However, several studies have also revealed the dynamic nature of genome size evolution and its considerable ‘ups’ and ‘downs’. Thus, in this study, the phylogenetic relationships among three previously revealed genome size groups and among species of the highly polyploid genus Curcuma were evaluated using AFLP. Our results suggest two main lineages within Indian Curcuma reflecting evolution of genome size. The first one includes hexaploids and higher polyploids of the previously recognized genome size group I, and the second one includes mainly hexaploids of genome size groups II and III. Within genome size group I, relationships among species seem to be influenced by reticulate evolution and higher polyploids are likely to be of allopolyploid origin. Reproductive systems in Indian Curcuma vary considerably among ploidy levels and these differences considerably affect morphological and genetic variation. In general, clonally reproducing species are expected to exhibit low genotypic diversity, but, at the same time, species of allopolyploid origin are expected to maintain higher levels of heterozygosity compared with their progenitors. We investigated intra‐populational genetic variability in Curcuma spp. to evaluate whether mode of reproduction or ploidy represent the main factor influencing the degree of genetic diversity. We found that hexaploid species exhibited significantly higher genetic diversity than higher polyploids (9x, 15x). Our results suggest that this genetic diversity pattern is largely influenced by the mode of reproduction, as higher polyploids reproduce exclusively vegetatively, whereas hexaploids reproduce mainly sexually. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 165 , 388–401.     

Evaluation of Turtle Exclusion and Escapement Devices for Hoop-Nets

Abstract Baited and unbaited hoop-nets commonly are used to capture catfish in lotic and lentic systems. Turtle bycatch and post-capture mortality has been problematic during catfish surveys in Missouri, USA, most recently in the Gasconade River, Gasconade and Osage counties. We evaluated 3 modified hoop-net designs that would reduce turtle bycatch without reducing catfish capture in the Gasconade River during 15 May-15 July 2006 after pilot study evaluation of 5 hoop-net designs in April 2006. We deployed modified and control-nets in blocks for 48 hours to evaluate differences in turtle and catfish catch rate, as well as abundance, size, and mortality rate of turtle bycatch. The chimney design reduced turtle bycatch by 84% when compared to the control, without decreasing the number or average size of captured flathead catfish (Pylodictis olivaris). Environmental conditions that affected turtle mortality included Secchi disc transparency, temperature, dissolved oxygen, and stream river depth. This is the first known attempt to create turtle exclusion or escapement devices for hoop-nets deployed in freshwater systems. Biologists using hoop-nets to sample aquatic vertebrates in moderate to large river systems will benefit from our study. The application of this methodology will reduce turtle bycatch mortality, especially when sampling is conducted in high water temperatures.     

Genetic structure of Eurasian badgers Meles meles (Carnivora: Mustelidae) and the colonization history of Ireland

The present study examined the contemporary genetic composition of the Eurasian badger, Meles meles, in Ireland, Britain and Western Europe, using six nuclear microsatellite loci and a 215‐bp fragment of the mitochondrial DNA control region. Significant population structure was evident within Europe (global multilocus microsatellite F_ST = 0.205, P < 0.001; global mitochondrial control region Φ_ST = 0.399, P < 0.001). Microsatellite‐based cluster analyses detected one population in Ireland, whereas badgers from Britain could be subdivided into several populations. Excluding the island populations of Ireland and Britain, badgers from Western Europe showed further structuring, with evidence of discrete Scandinavian, Central European, and Spanish populations. Mitochondrial DNA cluster analysis grouped the Irish population with Scandinavia and Spain, whereas the majority of British haplotypes grouped with those from Central Europe. The findings of the present study suggest that British and Irish badger populations colonized from different refugial areas, or that there were different waves of colonization from the source population. There are indications for the presence of an Atlantic fringe element, which has been seen in other Irish species. We discuss the results in light of the controversy about natural versus human‐mediated introductions. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

The minute books of the Linnean Club, from 1811 to 1955

Sometime during the early spring of 1970 I was asked to write an account of our old minute books and was given a large box containing many books and sundry papers. All the old books were there and in good condition, except the first–1811 to 1815. So I wrote a report lamenting the absence of this book, but afterwards it turned up. It had never been lost, but being rather different from all the others it was not recognized. I now think this was rather fortunate, for the first book which is the most interesting, deserves ampler treatment. My report is kept strictly on the books, and only very occasionally have I drawn on information from the Society's records, or from the introduction to the list of the Club compiled by H. W. Monckton in 1922, using the Society's records.     

The ecological significance of exchange processes between rivers and groundwater

1. This review focuses on the connectivity between river and groundwater ecosystems, viewing them as linked components of a hydrological continuum. Ecological processes that maintain the integrity of both systems and those that are mediated by their ecotones are evaluated. 2. The hyporheic zone, as the connecting ecotone, shows diverse gradients. Thus it can be characterized by hydrological, chemical, zoological and metabolic criteria. However, the characteristics of the hyporheic zone tend to vary widely in space and time as well as from system to system. The exact limits are difficult to designate and the construction of static concepts is inadequate for the representation of ecological processes. The hyporheic interstices are functionally a part of both the fluvial and groundwater ecosystems. 3. The permeability of the ecotone depends on the hydraulic conductivity of the sediment layers which, because of their heterogeneity, form many flowpath connections between the stream and the catchment, from the small scale of a single microhabitat to the large scale of an entire alluvial aquifer. Local up- and downwellings are determined by geomorphologic features such as streambed topography, whereas large-scale exchange processes are determined mainly by the geological properties of the catchment. Colmation—clogging of the top layer of the channel sediments—includes all processes leading to a reduction of pore volume, consolidation of the sediment matrix, and decreased permeability of the stream bed. Consequently, colmation can hinder exchange processes between surface water and groundwater. 4. Physicochemical gradients in the interstices result from several processes: (i) hyporheic flow pattern and the different properties of surface and groundwaters; (ii) retention, caused by the filtering effect of pore size and lithologic sorption as well as the transient storage of solutes caused by diminished water velocities; (iii) biogeochemical transformations in conjunction with local residence time. Each physicochemical parameter may develop its own vertical dynamics laterally from the active channel into the banks as well as longitudinally because of geomorphologic changes. 5. The river–groundwater interface can act as a source or sink for dissolved organic matter, depending on the volume and direction of flow, dissolved organic carbon concentrations and biotic activity. Interstitial storage of particulate organic matter is influenced mainly by grain size distribution and by spates involving bedload movement that may import or release matter, depending on the season. After initial transient and abiotic storage, hyporheic organic matter is mobilized and transformed by the biota. Micro-organisms account for over 90% of the community respiration. In subterranean waters most bacteria are attached to surfaces and remain in a biofilm. 6. Hyporheic interstices are functionally significant for phreatic and riverine metazoans because they act as a refuge against adverse conditions. The net flow direction exerts a dominant influence on interstitial colonization, but many other factors also seem to be important in structuring the hyporheos. 7. The hyporheic corridor concept emphasizes connectivity and interactions between subterranean and surface flow on an ecosystem level for floodplain rivers. It is a complementary concept to others which focus on surficial processes in the lateral and longitudinal dimensions. 8. The ecological integrity of groundwater and fluvial systems is often threatened by human activities: (i) by reducing connectivity; (ii) by altering exchange processes; and (iii) by toxic or organic contamination.     

Consequences of reduced nutrient loading on a lake system in a lowland catchment: deviations from the norm?

1. Lake restoration from eutrophication often rests on a simple paradigm that restriction of phosphorus sources will result in recovery of former relatively clear‐water states. This view has apparently arisen from early successful restorations of deep lakes in catchments of poorly weathered rocks. Lakes in the lowlands, however, particularly shallow ones, have proved less tractable to restoration. This study of three lowland lakes provides insights that illuminate a more complex picture. 2. The lakes lie in a sequence along a single stream in a mixed urban and rural landscape. Severely deoxygenating effluent from an overloaded sewage treatment works was diverted from the catchment in 1991. Effects on two lakes, Little Mere (z_max <2 m) and Rostherne Mere (z_max 31 m) were followed until 2002. Mere Mere (z_max = 8 m), upstream of the former works, acted as a comparison for changes in water chemistry. Mere Mere showed no change in total phosphorus (TP), total inorganic nitrogen, or planktonic chlorophyll a concentrations. Increased winter rainfall was associated with higher winter soluble reactive phosphorus (SRP) and ammonium concentrations in its water. 3. Little Mere changed from a deoxygenated, highly enriched, fishless system, with large populations of Daphnia magna Straus, clear water and about 40% aquatic plant cover, to a slightly less clear system following diversion. Daphnia magna was replaced by D. hyalina Leydig as fish recolonised. Spring peaks of chlorophyll a declined but summer concentrations increased significantly. Annual mean chlorophyll a concentrations thus showed no change. Submerged plants became more abundant (up to 100% cover), with fluctuating community composition from year to year. Summer release of SRP from the sediment was substantial and has not decreased since 1993. The summer phytoplankton was apparently controlled by nitrogen availability perhaps with some influence of zooplankton grazing. SRP was always very abundant. The lake appeared to have reached a quasi‐stable state by 2002. 5. Rostherne Mere showed a steady decline in TP and SRP concentrations following effluent diversion apparently as a result of steady dilution by water with lower phosphorus concentration. Decline in phosphorus concentrations was much less rapid than expected because of internal remobilisation from the hypolimnion and sediments. There have been no changes in chlorophyll a concentration or of nitrogen availability and by 2002 the phytoplankton probably remained limited by a combination of mixing, grazing and nitrogen. 6. A seeming paradox is, thus, that immense changes in phosphorus budgets have shown no consequences for phytoplankton chlorophyll concentrations in either of the lakes, although the seasonal distribution has altered in Little Mere. Although these case studies deviate from others, for both shallow and deep lakes, they represent distinctive situations rather than undermining conventional models.