Weak large‐scale population genetic structure in a philopatric seabird,the European Shag Phalacrocorax aristotelis

Quantifying population genetic structure is fundamental to testing hypotheses regarding gene flow, population divergence and dynamics across large spatial scales. In species with highly mobile life‐history stages, where it is unclear whether such movements translate into effective dispersal among discrete philopatric breeding populations, this approach can be particularly effective. We used seven nuclear microsatellite loci and mitochondrial DNA (ND2) markers to quantify population genetic structure and variation across 20 populations (447 individuals) of one such species, the European Shag, spanning a large geographical range. Despite high breeding philopatry, rare cross‐sea movements and recognized subspecies, population genetic structure was weak across both microsatellites and mitochondrial markers. Furthermore, although isolation‐by‐distance was detected, microsatellite variation provided no evidence that open sea formed a complete barrier to effective dispersal. These data suggest that occasional long‐distance, cross‐sea movements translate into gene flow across a large spatial scale. Historical factors may also have shaped contemporary genetic structure: cluster analyses of microsatellite data identified three groups, comprising colonies at southern, mid‐ and northern latitudes, and similar structure was observed at mitochondrial loci. Only one private mitochondrial haplotype was found among subspecies, suggesting that this current taxonomic subdivision may not be mirrored by genetic isolation.     

Systematic planning for river rehabilitation: integrating multiple ecological and economic objectives in complex decisions

1. Owing to intensive human use, freshwaters are among the most seriously threatened and modified environments on the planet. Their poor condition and the risk to services that humans need from these ecosystems make their rehabilitation a priority. However, many previous studies have reported the poor performance of many rehabilitation activities. 2. Here, we analyse reasons for this poor performance, focussing on the planning of rehabilitation activities, and propose a new approach. We argue that the failure to include driving factors at a scale adequate to capture the ecological processes involved, together with an insufficient incorporation of socio‐economic aspects, is a key factor leading the poor performance of many rehabilitation activities. 3. We propose a new approach, ‘systematic rehabilitation planning’, that brings together advances made in conservation planning (cost‐effectiveness analysis) and ecosystem science (understanding the complexity of ecosystem processes). This enables planning to be done at the catchment scale, and the trade‐offs between various rehabilitation actions to be integrated and prioritised. 4. Finally, it is important, given the constraints imposed by a lack of knowledge, that the planning process is part of an adaptive cycle where it can benefit from and consolidate the experience gained during the implementation and monitoring stages.     

A Comparison of Changes in the Germination Responses and Phospholipid Composition of Naturally and Artificially Aged Tomato Seeds

The changes in germinability and phospholipid content of naturallyand artificially aged tomato seeds, variety Kingley Cross, werecompared. Subsequent low temperature pre-sowing treatment (LTPST)was unable to prevent decreases in the germination capacityof aged samples, but significantly improved germination rates.However, in contrast to previous studies on artificial ageingusing the variety Moneymaker, losses of total phospholipid werenot always well correlated with decreased germinability. Totalphospholipid levels in naturally aged seeds were largely unaffectedby pre-sowing treatment, but the proportion of phosphatidylcholinewas greatly increased. These results strongly suggest that lossesof phospholipid are coincidental rather than causative eventsin the loss of seed viability during ageing, and that the patternof changes depends on the type of ageing experienced by theseeds. Controlled deterioration, seed ageing, tomato seeds, seed treatment, phospholipids     

Design and Evaluation of a Simple Signaling Device for Live Traps

Abstract: Frequent checks of live traps require enormous amounts of labor and add human scents associated with repeated monitoring, which may reduce capture efficiency. To reduce efforts and increase efficiency, we developed a trap-signaling device with long-distance reception, durability in adverse weather, and ease of transport, deployment, and use. Modifications from previous designs include a normally open magnetic switch and a mounting configuration to maximize reception. The system weighed <225 g, was effective ≤17.1 km, and failed in <1% of trap-nights. Employing this system, researchers and wildlife managers may reduce the amount of effort checking traps while improving the welfare of trapped animals.     

Dual Pattern of Potassium Transport in Plant Cells: A Physical Artifact of a Single Uptake Mechanism

Analysis of potassium transport in plant root cells shows tworate-influencing regions: an unstirred boundary layer adjacentto the cell wall acts as a rate-limiting region and the negativelycharged cell wall acts as a rate-enhancing region. The rate-enhancingregion gives rise to a pseudo ‘dual mechanism’.These two regions act in concert to influence significantlythe characteristics of the concentration-dependent potassiumuptake process. The anomalous ion uptake behaviour found inthe literature is explained on the basis of a single activeuptake mechanism operating under the influence of these tworegions. The most critical property in support of the conceptof a ‘dual mechanism’ for cation uptake in plantroots is explained on this basis. It is unnecessary to invokeseparate groups of enzymes, each one of which is active overdifferent concentration ranges. One mechanism operating overthe entire concentration range is sufficient. Key words: Potassium transport, Rate-limiting region, Rate-enhancing region     

Differences in Cell Cycle Duration of Sister Cells in Secondary Root Meristems of Cocos nucifera L.

Cell lengths of Gl/Gl pairs of sister cells and in mitotic packetsof cells were measured in secondary roots of Cocos nuciferaL. Due to symplastic growth cell length ratios of sister cells,over a cell cycle, remained constant for the dwarf, hybrid andtall varieties of C. nucifera; the mean cell length ratio, betweenthe larger and smaller cell, was between 116:1 and 1 –20:1.From the cell length ratios, mean differences in cell cycleduration for sister cells were calculated to lie between 0–22and 0–27 of the average cell cycle duration. Cumulative distributions of the cell length ratios of sistercells, when converted to differences in cell cycle durationand plotted on semi-log graph paper deviated from an exponentialdistribution. In 86 per cent of the sister cells studied, thelarger cell of a sister pair divided first, however in the remaining14 per cent, half had the smaller cell of a sister pair dividingfirst while in the other half of the sister pairs, the cellswere of equal length but one had entered mitosis ahead of itssister. These results support neither cell cycle models basedon a cell sizer control per se nor on a random transition frominactive to active parts of the cell cycle.     

The separation of Pterodroma madeira (Zino's Petrel) from Pterodroma feae (Fea's Petrel) (Aves: Procellariidae)

The taxonomic status of petrels from the North East Atlantic has long been a matter of debate. Breeding colonies of petrels occurring on the islands of Madeira, Bugio and Cape Verde were originally thought to be outlying populations of the polytypic species Pterodroma mollis . Subsequent taxonomic treatments have varied considerably in their classification of birds from these islands. The petrel populations on Madeira and Bugio represent some of Europe's rarest breeding birds and their exact species designation, and hence relation to conservation mandates, is a question of considerable importance. In this study we use molecular techniques alongside more traditional taxonomic characters to confirm the existence of two species of the genus Pterodroma in the Archipelago of Madeira. We also discuss identification of these species in the field and the implications for their conservation management.