Isolation mediates persistent founder effects on zooplankton colonisation in new temporary ponds

Understanding the colonisation process in zooplankton is crucial for successful restoration of aquatic ecosystems. Here, we analyzed the clonal and genetic structure of the cyclical parthenogenetic rotifer Brachionus plicatilis by following populations established in new temporary ponds during the first three hydroperiods. Rotifer populations established rapidly after first flooding, although colonisation was ongoing throughout the study. Multilocus genotypes from 7 microsatellite loci suggested that most populations (10 of 14) were founded by few clones. The exception was one of the four populations that persisted throughout the studied hydroperiods, where high genetic diversity in the first hydroperiod suggested colonisation from a historical egg bank and, no increase in allelic diversity was detected with time. In contrast, in another of these four populations, we observed a progressive increase of allelic diversity. This population became less differentiated from the other populations suggesting effective gene flow soon after its foundation. Allelic diversity and richness remained low in the remaining two, more isolated, populations, suggesting little gene flow. Our results highlight the complexity of colonisation dynamics, with evidence for persistent founder effects in some ponds, but not in others, and with early immigration both from external source populations, and from residual, historical diapausing egg banks

Colonization and dispersal patterns of the invasive American brine shrimp Artemia franciscana (Branchiopoda: Anostraca) in the Mediterranean region

Cysts of the brine shrimp Artemia franciscana are harvested from the Great Salt Lake (GSL) and San Francisco Bay (SFB) saltworks in the USA, and marketed worldwide to provide live food for aquaculture. This species has become invasive across several countries. We investigated (1) if the introduced populations in the Mediterranean region could have originated from these USA populations, (2) how the genetic diversity of Mediterranean compares to that at GSL and SFB, and (3) if genetic patterns in the Mediterranean can shed light on colonization routes. We sequenced a fragment of the cytochrome c oxidase subunit I and screened microsatellites loci from Mediterranean populations and the two putative USA sources. Haplotypes from Mediterranean populations were identical or closely related to those from SFB and GSL, and not related to other available American populations. Microsatellite analyses showed a reduced population diversity for most Mediterranean populations suggesting bottleneck effects, but few populations were showing similar or higher genetic diversity than native ones, which are likely to be admixed from both GSL and SFB because of multiple introductions. Results suggest natural dispersal, potentially via flamingos, between two Spanish populations. Our analyses show that all invaded populations could have originated from those commercialized USA populations. © 2013 Springer Science+Business Media Dordrecht

Immigration enhances fast growth of a newly established source population

Immigration and local recruitment play a central role in determining the growth rate of breeding populations. Unraveling these processes in newly established pop-ulations is of great importance to increase our understanding of how species change their distributions in response to global change. We studied the largest colony of glossy ibis (Plegadis falcinellus) in Western Europe (established in 1996 in Doñana, SW- Spain) by using capture- recapture methods, count estimates, and projection matrix modeling to: (1) test the effect of resource availability and competition on local recruitment dynamics, (2) inves-tigate the contribution of local recruitment vs. immigration on population growth, and (3) assess the role of this population in source/sink dynamics. We found different dynamics before and after the establishment of satellite colonies in Doñana in 2004. Between 1996 and 2003, the population increased rapidly, fueled by immigrants (≈58 breeding females/yr). Between 2003 and 2007, however, both colony size increase and immigration were negligible. Immigration played a major role in colony growth, but simultaneously this colony was a source population driving expansion of the species range as suggested by (1) absolute and relative estimates of the observed growth rate relative to that predicted by self- recruitment, and (2) numerous observations of Doñana- born individuals breeding elsewhere. Local recruitment, which was particularly high for first- year individuals (prob-ability >0.8 for the early study years), was not directly related to resource availability or previous- year breeding success. Local recruitment decreased rapidly at a threshold popu-lation size, however, when other satellite colonies became established at Doñana. Our study suggests that even when recruitment at an early age and high productivity are observed, immigration can still play a pivotal role in promoting the fast growth of new populations at the edge of a species range, at least until density- dependent effects arise. This process can be so fast that within a few years a new population can itself become a source population, further driving range expansion of the species.Peer reviewe

Genetic studies facilitated management decisions on the invasion of the ruddy duck in Europe

The ruddy duck (Oxyura jamaicensis), a stifftail native to the Americas, was introduced to the UK in the 1950s and has since been recorded in 22 western Palearctic countries. By 2000, the UK popu- lation peaked at nearly 6,000 individuals. In 1991, hybridisation with the native and globally threatened (IUCN Endangered) white-headed duck (Oxyura leu- cocephala), a stifftail restricted to the Mediterranean and Asia, was recorded in Spain and culling of hybrids and ruddy ducks began. Here we report on a series of genetic studies that have enabled and supported management decisions to the benefit of the white- headed duck. First, genetic data confirmed that these are two distinct species, each of which is more closely related to other stifftail species. Second, molecular studies indicated that ruddy ducks in Spain, Iceland and elsewhere in Europe were of captive origin and not descendants from vagrants from their native North America. Third, genetic methods were used to distin- guish among different hybrid generations in Spain and detected no ruddy duck introgression in birds identi- fied morphologically as white-headed ducks. Collec- tively, these results supported management decisions to eradicate ruddy ducks from Europe. Subsequently, a control programme reduced the UK population by over 95 % by 2010, and the arrival of ruddy ducks to Spain decreased from 21 birds in 2003 to two sightings in 2010–2011. However, increased efforts to control small ruddy duck populations elsewhere in Europe and Morocco are still required to ensure conservation of the white-headed duck. This case of invasion by hybridization demonstrates that successful control is feasible given early detection followed by a rapid response plan; it also shows the contribution of research to management and that to guarantee the conservation of an endangered native species action may be required in countries outside its distribution range.Peer reviewe

Rice grain cadmium concentrations in the global supply-chain

Artículo escrito por un elevado número de autores, solo se referencia el que aparece en primer lugar, el nombre del grupo de colaboración, si lo hubiere, y los autores pertenecientes a la UAMOne of cadmium’s major exposure routes to humans is through rice consumption. The concentrations of cadmium in the global polished (white), market rice supply-chain were assessed in 2270 samples, purchased from retailers across 32 countries, encompassing 6 continents. It was found on a global basis that East Africa had the lowest cadmium with a median for both Malawi and Tanzania at 4.9 μg/kg, an order of magnitude lower than the highest country, China with a median at 69.3 μg/kg. The Americas were typically low in cadmium, but the Indian sub-continent was universally elevated. In particular certain regions of Bangladesh had high cadmium, that when combined with the high daily consumption rate of rice of that country, leads to high cadmium exposures. Concentrations of cadmium were compared to the European Standard for polished rice of 200 μg/kg and 5% of the global supply-chain exceeded this threshold. For the stricter standard of 40 μg/kg for processed infant foods, for which rice can comprise up to 100% by composition (such as rice porridges, puffed rice cereal and cakes), 25% of rice would not be suitable for making pure rice baby foods. Given that rice is also elevated in inorganic arsenic, the only region of the world where both inorganic arsenic and cadmium were low in grain was East Afric

Dispersal of Plants by Waterbirds

The widespread distribution of fresh-water plants and of the lower animals, whether retaining the same identical form or in some degree modified, I believe mainly depends on the wide dispersal of their seeds and eggs by animals, more especially by fresh-water birds, which have large powers of flight, and naturally travel from one to another and often distant piece of water. — Charles Darwin (1859)Peer reviewe

Seed dispersal by dabbling ducks: an overlooked dispersal pathway for a broad spectrum of plant species

1. Dabbling ducks (Anatinae) are omnivorous birds that are widespread, numerous, highly mobile and often migratory, and therefore have great potential for (long distance) dispersal of other organisms, including plants. However, their ability to act as plant dispersal vectors has received little attention compared to frugivores and is often assumed to be relevant only for wetland species. 2. To evaluate the potential for plant dispersal by dabbling ducks, we collated and analysed existing data. We identified all plant species whose seeds have been recorded in the diets of the seven dabbling duck (Anas) species in the Western Palaearctic, as reported from gut content analyses. We then analysed the habitats and traits of these plant species to identify general patterns, and related these to data on gut passage survival and duck movements. 3. A large number of plant species (> 445 species of 189 genera and 57 families) have been recorded in the diet of dabbling ducks. These plant species represent a very wide range of habitats, including almost the full range of site fertility, moisture and light conditions, excluding only very dry and deeply shaded habitats. The ducks prefer seeds of intermediate sizes (1–10 mm3), which have good chances to survive gut passage, but also ingest smaller and larger seeds. Ingested seeds represent a wide range of dispersal syndromes, including fleshy fruits. Many species (62%) were not previously considered animal- dispersed in plant data bases, and 66% were not identified as bird-dispersed. Rarefaction analyses suggest that our analysis still greatly underestimates the total number of plant species ingested. 4. Synthesis. Dabbling ducks do not exclusively ingest seeds of wetland plants, which make up only 40% of the ingested species. Rather, they feed opportunistically on a wide cross-section of plant species available across the landscapes they inhabit. Given the millions of ducks, the hundreds to thousands of seeds ingested per individual on a daily basis, and known gut passage survival rates, this results in vast numbers of seeds dispersed by ducks per day. Internal seed dispersal by dabbling ducks appears to be a major dispersal pathway for a far broader spectrum of plant species than previously consideredPeer reviewe

A comparison of spectacles purchased online and in UK optometry practice

YesPurpose: To compare spectacles bought online with spectacles from optometry practices. Methods: Thirty-three participants consisting of single vision spectacle wearers with either a low (N = 12, mean age 34 ± 14 years) or high prescription (N = 11, mean age 28 ± 9 years) and 10 presbyopic participants (mean age 59 ± 4 years) wearing progressive addition lenses (PALs) purchased 154 pairs of spectacles online and 154 from UK optometry practices. The spectacles were compared via participant-reported preference, acceptability, and safety; the assessment of lens, frame, and fit quality; and the accuracy of the lens prescriptions to international standard ISO 21987:2009. Results: Participants preferred the practice spectacles (median ranking 4th, IQR 1–6) more than online (6th, IQR 4–8; Mann-Whitney U = 7345, p < 0.001) and practice PALs (median ranking 2nd, IQR 1–4) were particularly preferred (online 6.5th, IQR 4–9, Mann-Whitney U = 455, p < 0.001). Of those deemed unacceptable and unsafe, significantly more were bought online (unacceptable: online 43/154 vs. practice 15/154, Fisher’s exact p = 0.0001; unsafe: online 14/154 vs. practice 5/154, Fisher’s exact p = 0.03). Conclusions: Participants preferred spectacles from optometry practice rather than those bought online, despite lens quality and prescription accuracy being similar. A greater number of online spectacles were deemed unsafe or unacceptable because of poor spectacle frame fit, poor cosmetic appearance, and inaccurate optical centration. This seems particularly pertinent to PAL lenses, which are known to increase falls risk. Recommendations are made to improve both forms of spectacle provision.College of Optometrist

Projected health effects of realistic dietary changes to address freshwater constraints in India : a modelling study

Acknowledgements This study forms part of the Sustainable and Healthy Diets in India project supported by the Wellcome Trust's Our Planet, Our Health programme (grant number 103932). LA's PhD is funded by the Leverhulme Centre for Integrative Research on Agriculture and Health. SA is supported by a Wellcome Trust Capacity Strengthening Strategic Award-Extension phase (grant number WT084754/Z/08/A). We would like to thank Zaid Chalabi (London School of Hygiene & Tropical Medicine) for providing valuable guidance on the modelling methods.Peer reviewedPublisher PD