Exclusion of ground predators improves Northern Lapwing Vanellus vanellus chick survival

Many farmland‐breeding wader species have declined across Europe, probably due to reductions in reproductive output caused by high nest losses as a result of agriculture or predation, or low chick survival between hatching and fledging. Most studies have focused on nest failures, and the factors affecting post‐hatching survival of chicks are poorly known. In an experimental approach, we fenced parts of the arable foraging areas of Northern Lapwing Vanellus vanellus families to quantify chick survival simultaneously in the presence and absence of ground predators. Lapwing chicks were radiotagged to estimate survival probabilities by daily locations, applying multistate capture–recapture models. During the night, chick survival was considerably lower outside fenced plots than within. During the day, chick survival was higher than at night and did not differ between protected and unprotected plots. This suggests that nocturnal ground predators such as Red Foxes Vulpes vulpes were responsible for a significant proportion of chick mortality. Cumulative survival probability from hatching to fledging was 0.24 in chicks within fenced plots, but virtually zero in chicks outside fenced plots. In farmland, temporary electric fences can be effective in minimizing the impact of ground predators and offer a promising short‐term method to increase fledging success of precocial birds.     

Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance

Estimates of carbon leaching losses from different land use systems are few and their contribution to the net ecosystem carbon balance is uncertain. We investigated leaching of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and dissolved methane (CH₄), at forests, grasslands, and croplands across Europe. Biogenic contributions to DIC were estimated by means of its δ¹³C signature. Leaching of biogenic DIC was 8.3±4.9 g m^?2 yr^?1 for forests, 24.1±7.2 g m^?2 yr^?1 for grasslands, and 14.6±4.8 g m^?2 yr^?1 for croplands. DOC leaching equalled 3.5±1.3 g m^?2 yr^?1 for forests, 5.3±2.0 g m^?2 yr^?1 for grasslands, and 4.1±1.3 g m^?2 yr^?1 for croplands. The average flux of total biogenic carbon across land use systems was 19.4±4.0 g C m^?2 yr^?1. Production of DOC in topsoils was positively related to their C/N ratio and DOC retention in subsoils was inversely related to the ratio of organic carbon to iron plus aluminium (hydr)oxides. Partial pressures of CO₂ in soil air and soil pH determined DIC concentrations and fluxes, but soil solutions were often supersaturated with DIC relative to soil air CO₂. Leaching losses of biogenic carbon (DOC plus biogenic DIC) from grasslands equalled 5–98% (median: 22%) of net ecosystem exchange (NEE) plus carbon inputs with fertilization minus carbon removal with harvest. Carbon leaching increased the net losses from cropland soils by 24–105% (median: 25%). For the majority of forest sites, leaching hardly affected actual net ecosystem carbon balances because of the small solubility of CO₂ in acidic forest soil solutions and large NEE. Leaching of CH₄ proved to be insignificant compared with other fluxes of carbon. Overall, our results show that leaching losses are particularly important for the carbon balance of agricultural systems.     

Latitudinal patterns of magnitude and interannual variability in net ecosystem exchange regulated by biological and environmental variables

Over the last two and half decades, strong evidence showed that the terrestrial ecosystems are acting as a net sink for atmospheric carbon. However the spatial and temporal patterns of variation in the sink are not well known. In this study, we examined latitudinal patterns of interannual variability (IAV) in net ecosystem exchange (NEE) of CO₂ based on 163 site-years of eddy covariance data, from 39 northern-hemisphere research sites located at latitudes ranging from ∼29°N to ∼64°N. We computed the standard deviation of annual NEE integrals at individual sites to represent absolute interannual variability (AIAV), and the corresponding coefficient of variation as a measure of relative interannual variability (RIAV). Our results showed decreased trends of annual NEE with increasing latitude for both deciduous broadleaf forests and evergreen needleleaf forests. Gross primary production (GPP) explained a significant proportion of the spatial variation of NEE across evergreen needleleaf forests, whereas, across deciduous broadleaf forests, it is ecosystem respiration (Re). In addition, AIAV in GPP and Re increased significantly with latitude in deciduous broadleaf forests, but AIAV in GPP decreased significantly with latitude in evergreen needleleaf forests. Furthermore, RIAV in NEE, GPP, and Re appeared to increase significantly with latitude in deciduous broadleaf forests, but not in evergreen needleleaf forests. Correlation analyses showed air temperature was the primary environmental factor that determined RIAV of NEE in deciduous broadleaf forest across the North American sites, and none of the chosen climatic factors could explain RIAV of NEE in evergreen needleleaf forests. Mean annual NEE significantly increased with latitude in grasslands. Precipitation was dominant environmental factor for the spatial variation of magnitude and IAV in GPP and Re in grasslands.     

Histopathology of virus-like particles in Heliothis spp

Larvae of Heliothis spp. collected from cotton, soybean, and peanut fields in South Carolina were found to be infected with virus-like particles (VLPs). Infected larvae became pale and swollen, stopped feeding, and remained alive for 2–3 weeks. Hemolymph from these larvae was milky and contained numerous spherical bodies ranging in diameter from 2 to 10 μm. The hemolymph also contained VLPs which were oval and measured 375 × 125 nm. Infectivity tests with crude saline extracts of infected larvae demonstrated that the pathogen could be transmitted by injection but not per os. The spherical bodies contained VLPs (387 × 149 nm) surrounded by two envelopes and packed together in clusters. These VLPs were also found in fat body cells, cuticular epithelial cells, tracheal cells, and connective tissue associated with the body wall and the gut. They were not found in muscle tissue or in midgut epithelial cells. Similar VLPs have been found in Heliothis zea from Mississippi and Trichoplusia ni from California, but a positive identification of the VLPs has not been made in any of these studies. Morphologically they appear to be distinct from any other previously described insect viruses.     

The infectivity of a nuclear polyhedrosis virus of the velvetbean caterpillar for eight noctuid hosts

Eight species of noctuid larvae were tested for susceptibility to a nuclear polyhedrosis virus of the velvetbean caterpillar, Anticarsia gemmatalis. Velvetbean caterpillar larvae were highly susceptible to crude preparations of polyhedral inclusion bodies (PIBs; LD₅₀ = 4.7 PIBs/larva), but preparations of purified polyhedra were much less effective against these larvae (LD₅₀ = 319.7 PIBs/larva). Of seven other noctuid species tested, only Heliothis virescens was as susceptible to the virus as A. gemmatalis. High dosages were required to kill Heliothis zea, Trichoplusia ni, Pseudoplusia includens, and Spodoptera ornithogalli. Plathypena scabra and Spodoptera frugiperda were not susceptible.     

Characterization of three ascovirus isolates from cotton insects

Three new ascovirus isolates were discovered from lepidopteran larvae in cotton fields in Blackville, South Carolina, USA, and were named TnAV-2c, TnAV-2d, and HvAV-3f. TnAV-2c and TnAV-2d were compared by restriction endonuclease (REN) profiles and found to be similar. HvAV-3f was isolated from Helicoverpa zea, and bears remarkable dissimilarity in REN profiles to the reported SeAV-5a from Spodoptera exigua but DNA hybridization shows they are closely related. Major capsid protein (MCP) and delta DNA polymerase from the three isolates were sequenced, which suggests the three isolates are novel. Phylogenetic analyses showed that TnAV-2c is distantly related to other lepidopteran ascoviruses. HvAV-3f and SeAV-5a may also be variants of the same species based on Southern, Western, and MCP/DNA polymerase gene sequence analyses. High levels of TnAV-2 infection in an H. zea population (as high as 74%) were recorded in a cotton field in Blackville, SC. Observations in this field showed that infection by ascovirus altered the feeding behavior of H. zea larvae.     

Early Jurassic gastropods from England

Abstract: Twenty‐five gastropod taxa are reported from the Early Jurassic (Hettangian to Toarcian) of England. Of these, 14 are identified to species level, and the remaining 11 are treated in open nomenclature. One genus (Lensataphrus) and six species are introduced as new. The new species are Lensataphrus tatei, Lensataphrus tenuis, Tricarilda toddi, Cylindrobullina dorsetensis, Cylindrobullina ventricosa and Consobrinella greeni. The following new combinations are introduced: Cassianopsis hebertana (d’Orbigny, 1852) for Neritopsis hebertana; Cryptaulax abscisum (Terquem and Piette, 1868) for Cerithium abscisum; and Cylindrobullina avena (Terquem, 1855) for Striactaeonina avena. Most of the genera and some of the species are also known from Central Europe (Germany and France). Typical vetigastropod genera that are present in England and Central Europe are Colpomphalus, Costataphrus, Ooliticia, Eucycloscala and Eucycloidea. The caenogastropod genera Levipleura and Cryptaulax are present in both regions, as are the heterobranchs Tricarilda and Cylindrobullina. The heterobranch genus Consobrinella is reported from England for the first time. Gastropods seem to follow the diversity trends of other marine invertebrates during the Early Jurassic. They diversify until the Late Pliensbachian but decrease sharply in number around the Pliensbachian–Toarcian boundary. This may reflect both regional anoxia and a global mass extinction event in the Early Toarcian.     

Molecular and morphological variation of rare endemic oncocyclus irises (Iridaceae) of Lebanon

Oncocyclus irises endemic to Lebanon form a complex of three closely related taxa replacing each other over short geographical distances in a linear habitat. In order to characterize the appropriate taxonomic levels and to assess their conservation status, we investigated patterns of phenotypic variability and the partitioning of genetic variation within and among populations using random amplified polymorphic DNA (RAPD) markers. Multivariate analysis (principal components analysis and multiple correspondence analysis), based on 16 quantitative and six qualitative characters, revealed no separation between populations or taxa. Moreover, no morphological character could be used to define clear boundaries between populations/taxa. The genetic characterization revealed high levels of polymorphism and diversity (H_s). Principal components analysis showed population delimitations, but no groupings reflecting the currently defined taxa could be identified. Both morphological and genetic data showed that Lebanese oncocyclus irises could not be fitted into clear taxonomic boundaries. Consequences for conservation are discussed. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 123–135.