Fire,landscape change and models of small mammal habitat suitability at multiple spatial scales

Fire is an important process in many ecosystems, but inappropriate fire regimes can adversely affect biodiversity. We identified a naturally flammable heathy woodland ecosystem where the use of planned fire had increased the extent of older vegetation, and quantified the abundance of two small native mammals in this landscape (silky mouse Pseudomys apodemoides and heath rat P. shortridgei). We defined four time‐since‐fire (TSF) categories representing a 2‐ to 55‐year post‐fire sequence and, on the basis of a habitat accommodation model, predicted that both species would select younger age‐classes over older ones. We also predicted that (i) much of the variance in vegetation structure would remain unexplained by TSF and (ii) statistical models of mammal abundance and occupancy including structural variables as predictors would be better than models including TSF. Pseudomys apodemoides selected 17‐ to 23‐year‐old sites, while there was no evidence that P. shortridgei selected a particular TSF category, findings that were inconsistent with our predictions. In line with our predictions, relatively large portions of the variance in vegetation structure remained unexplained by TSF (adjustedr² for four structural variables: 0.24, 0.29, 0.35 and 0.57), and in three of four cases there was strong evidence that statistical models of mammal abundance and occupancy including structural variables were better than those including TSF. At the site scale (hectares), P. shortridgei abundance was positively related to the cover of dead material at the base of Xanthorrhoea plants and at the trap scale (metres), the trapability of both species was significantly related to vegetation volume at 0–20 cm. Our findings suggest that TSF may not be a good proxy for either vegetation structure or species abundance/occupancy.     

Reinvestigating good genes benefits of mate choice in Drosophila simulans

Studies investigating the genetic benefits of female mate choice frequently find Fisherian benefits to choice, at the same time as detecting small or no good genes (viability) effects. This could be because sons trade‐off viability for increased mating success and, accordingly, it has been suggested that good genes benefits should be investigated in daughters. However, good genes benefits via daughters could also be disrupted by intralocus sexual conflict. As a result, it is not clear when and if good genes benefits should accrue. We investigated potential good genes effects in Drosophila simulans using an isofemale line approach. We assessed the attractiveness of males in two different ways and then measured the longevity, as well as lifetime reproductive success, of their daughters. We also assessed potential direct benefits of female mate choice and good genes effects through the longevity of sons. We found no evidence of direct or good genes benefits to females mating with attractive males, and the failure to find good genes effects via daughters was apparently not a result of masking through intralocus sexual conflict. The results obtained in the present study are consistent with previous findings in this species, and suggest that good genes benefits are at best very small in our study population. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 295–306.     

Biological controls upon the physical taphonomy of exceptionally preserved salamanders from the Miocene of Rubielos de Mora,northeast Spain

McNamara, M.E., Orr, P.J., Manzocchi, T., Alcalá, L., Anadón, P. & Peñalver, E. 2011: Biological controls upon the physical taphonomy of exceptionally preserved salamanders from the Miocene of Rubielos de Mora, northeast Spain. Lethaia, Vol. 45, pp. 210–226. The middle Miocene Rubielos de Mora Konservat‐Lagerstätte of northeast Spain is hosted within profundal, finely laminated, lacustrine mudstones. The diverse biota includes abundant salamanders. Most individuals died during separate episodes and sank rapidly postmortem. Specimens are typically preserved in dorso‐ventral aspect, the most hydrodynamically stable orientation. The near‐cylindrical morphology of the body, however, allowed some carcasses to settle in or subsequently re‐orientate into, lateral orientations. Loss of skeletal elements (i.e. reduced completeness) reflects their location within the body and followed a distal to proximal trend. Two stages are identified: initial loss of a small number of phalanges, followed by loss of more proximal limb bones plus additional phalanges. Disarticulation is more complex: it occurred via several mechanisms (notably, abdominal rupture and re‐orientation of part of the body and limbs during decay) and shows no consistent pattern among specimens. The physical taphonomy of the salamanders is controlled predominantly by intrinsic biological factors, i.e. the geometry of the body and of individual skeletal elements, the orientation, inherent strength and location of specific joints and the extent to which soft tissues, particularly the skin, persist during decay. These biological factors probably control patterns of physical taphonomy of other fossil tetrapods with a similar skeletal configuration. □Articulation, completeness, Konservat‐Lagerstätten, orientation, quantitative taphonomy, salamanders.     

An integrative approach to characterize cryptic species in the Thoracostoma trachygaster Hope, 1967 complex (Nematoda: Leptosomatidae)

Nematode diversity may seriously be underestimated when taking into account cryptic speciation. Thoracostoma trachygaster is commonly found in kelp holdfasts along the California coastline and was recently shown to consist of at least two distinct molecular clades (I and II). Here, we provide detailed morphological analysis of both clades, based on measurements taken from video vouchers of respectively eight and 16 individuals from the previous study, as well as 80 newly collected specimens from four Californian beaches. The latter were vouchered, measured, and then subjected to molecular analyses of the mitochondrial cytochrome oxidase c subunit I (COI) gene, and the ribosomal D2D3 and internal transcribed spacer (ITS) regions. This integrative approach shows that the three molecular clades are phylogenetically and morphologically distinct species, but a combination of morphological characters is needed to distinguish them. Two new species, Thoracostoma fatimae sp. nov. and Thoracostoma igniferum sp. nov. , are identified and described. The spicule length of T. fatimae sp. nov. is significantly shorter than that of T. trachygaster. Thoracostoma igniferum sp. nov. can be distinguished by the irregular posterior edge of the cephalic capsule and the two internal subdorsal tropis‐like projections in the wall of the cephalic capsule, which are lacking in T. fatimae sp. nov. and T. trachygaster. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 18–35.     

Influence of an ecosystem engineer,the emergent macrophyte Sparganium erectum,on seed trapping in lowland rivers and consequences for landform colonisation

1. Plant physical ecosystem engineers can influence vegetation population and community dynamics by modifying, maintaining or creating habitats. They may also have the potential to act upon biotic processes, such as seed dispersal. 2. Examples exist of reduction in seed dispersal distances in vegetated compared to unvegetated terrestrial environments, and concentration of seed deposits associated with plant patches. Such effects in aquatic environments have been little studied, but the engineering effect of plant patches on patterns of flow velocity and sediment deposition in streams suggests that they may play a similar role. 3. In this study, we assess the potential of an emergent aquatic species, Sparganium erectum, to play a role in physically modifying river habitats and trapping seeds by examining patterns of seed deposition and substrate type in 47 river reaches across England and southern Scotland, U.K. 4. Areas of the river channel within or adjacent to S. erectum patches harboured more plant seeds and more species than unvegetated areas and had finer, sandier substrates with higher organic matter, total nitrogen and total phosphorus content. Most seed species were competitive, indicating that they were well suited to colonise the competitive environment of an S. erectum patch, and could potentially further stabilise accumulated sediments and contribute to landform development. 5. We demonstrate that S. erectum patches influence both the physical environment and the retention of seeds, in consistent patterns across the channel bed, for a range of lowland rivers that vary in stream power and geology and which can be expected to vary in levels of supply of fine sediment and seeds. 6. Our findings support the hypothesis that the fundamental influence of a riverine ecosystem‐engineering species on slowing fluid flow links the habitat creation process of sediment sorting and retention to seed trapping. We suggest the process is applicable to a wide range of aquatic and riparian vegetation. We also suggest that the mono‐specific and competitive growth, which is typical of these engineering species, will strongly influence the recruitment of trapped seeds.     

Species loss of stoneflies (Plecoptera) in the Czech Republic during the 20th century

1. Rapid expansion and intensification of anthropogenic activities in the 20th century has caused profound changes in freshwater assemblages. Unfortunately, knowledge of the extent and causes of species loss (SL) is limited due to the lack of reliable historical data. An unusual data set allows us to compare changes in the most sensitive of aquatic insect orders, the Plecoptera, at some 170 locations in the Czech Republic between two time periods, 1955–1960 and 2006–2010. Historical data (1890–1911) on assemblages of six lowland rivers allow us to infer even earlier changes. 2. Regional stonefly diversity decreased in the first half of the 20th century. Streams at lower altitudes lost a substantial number of species, which were never recovered. In the second half of the century, large‐scale anthropogenic pressure caused SL in all habitats, leading to a dissimilarity of contemporary and previous assemblages. The greatest changes were found at sites affected by organic pollution and a mixture of organic pollution and channelisation or impoundment. Colonisation of new habitats was observed in only three of the 80 species evaluated. 3. Species of moderate habitat specialisation and tolerance to organic pollution were most likely to be lost. Those with narrow specialisations in protected habitats were present in both historical and contemporary collections. 4. Contemporary assemblages are the consequence of more than a 100 years of anthropogenic impacts. In particular, streams at lower altitude and draining intensively exploited landscapes host a mere fragment of the original species complement. Most stonefly species are less frequently present than before, although their assemblages remain almost intact in near‐natural mountain streams. Our analyses demonstrate dramatic restriction of species ranges and, in some cases, apparent changes in altitudinal preference throughout the area.     

RESPECTING AUTONOMY WITHOUT DISCLOSING INFORMATION

There is widespread agreement that it would be both morally and legally wrong to treat a competent patient, or to carry out research with a competent participant, without the voluntary consent of that patient or research participant. Furthermore, in medical ethics it is generally taken that that consent must be informed. The most widely given reason for this has been that informed consent is needed to respect the patient's or research participant's autonomy. In this article I set out to challenge this claim by considering in detail each of the three most prominent ways in which ‘autonomy’ has been conceptualized in the medical ethics literature. I will argue that whilst these accounts support the claim that consent is needed if the treatment of competent patients, or research on competent individuals, is to respect their autonomy, they do not support the claim that informed consent is needed for this purpose.