Squeezed out: the consequences of riparian zone modification for specialist invertebrates

While anthropogenic biodiversity loss in fresh waters is among the most rapid of all ecosystems, impacts on the conservation of associated riparian zones are less well documented. Riverine ecotones are particularly vulnerable to the combined ‘squeeze’ between land-use encroachment, discharge regulation and climate change. Over a 3-year period of persistent low discharge in a regulated, temperate river system (River Usk, Wales, UK; 2009–2011), specialist carabid beetles on exposed riverine sediments (ERS) were used as model organisms to test the hypotheses that catchment-scale flow modification affects riparian zone invertebrates more than local habitat character, and that this modification is accompanied by associated succession among the Carabidae. Annual summer discharge during the study period was among the lowest of the preceding 12 years, affecting carabid assemblages. The richness of specialist ERS carabids declined, while generalist carabid species’ populations either increased in abundance or remained stable. Community composition also changed, as three (Bembidion prasinum, B. decorum and B. punctulatum) of the four dominant carabids typical of ERS increased in abundance while B. atrocaeruleum decreased. Despite significant inter-annual variation in habitat quality and the encroachment of ground vegetation, beetle assemblages more closely tracked reach-scale variations between sites or catchment-scale variations through time. These data from multiple sites and years illustrate how ERS Carabidae respond to broad-scale discharge variations more than local habitat character. This implies that the maintenance of naturally variable flow regimes is at least as important to the conservation of ERS and their dependent assemblages as are site-scale measures

Microcosm studies of the role of land plants in elevating soil carbon dioxide and chemical weathering

A decrease in atmospheric carbon dioxide (CO2) concentration during the mid-Palaeozoic is postulated to have been partially the consequence of the evolution of rooted land plants. Root development increased the amount of carbonic acid generated by root respiration within soils. This led to increased chemical weathering of silicates and subsequent formation of carbonates, resulting in lower atmospheric CO2 concentrations. To test this assumption, analog (morphologically equivalent) plant species, ranging from those possessing no roots to those with complex rhizomatous rooting systems, were grown in trays within microcosms at ambient (360 ppm/0.37 mbar) and highly elevated (3500 ppm/3.55 mbar) atmospheric CO2 concentrations in a controlled environment facility. Substrate CO2 concentrations increased significantly under elevated atmospheric CO2, and Equisetum hyemale (L.). The latter is postulated to result from the effects of deeply rooted plants, elevated atmospheric CO2 concentrations, or both. Plants with simple or no rooting systems or the addition of dead organic matter as a substrate for microorganisms did not enhance substrate CO2 concentrations

The effects of supplementary food on the breeding performance of Eurasian reed warblers Acrocephalus scirpaceus; implications for climate change impacts

Understanding the mechanisms by which climate variation can drive population changes requires information linking climate, local conditions, trophic resources, behaviour and demography. Climate change alters the seasonal pattern of emergence and abundance of invertebrate populations, which may have important consequences for the breeding performance and population change of insectivorous birds. In this study, we examine the role of food availability in driving behavioural changes in an insectivorous migratory songbird; the Eurasian reed warbler Acrocephalus scirpaceus. We use a feeding experiment to examine the effect of increased food supply on different components of breeding behaviour and first-brood productivity, over three breeding seasons (2012–2014). Reed warblers respond to food-supplementation by advancing their laying date by up to 5.6 days. Incubation periods are shorter in supplemented groups during the warmest mean spring temperatures. Nestling growth rates are increased in nests provisioned by supplemented parents. In addition, nest predation is reduced, possibly because supplemented adults spend more time at the nest and faster nestling growth reduces the period of vulnerability of eggs and nestlings to predators (and brood parasites). The net effect of these changes is to advance the fledging completion date and to increase the overall productivity of the first brood for supplemented birds. European populations of reed warblers are currently increasing; our results suggest that advancing spring phenology, leading to increased food availability early in the breeding season, could account for this change by facilitating higher productivity. Furthermore, the earlier brood completion potentially allows multiple breeding attempts. This study identifies the likely trophic and behavioural mechanisms by which climate-driven changes in invertebrate phenology and abundance may lead to changes in breeding phenology, nest survival and net reproductive performance of insectivorous birds

The impact of increased food availability on reproduction in a long-distance migratory songbird: implications for environmental change?

Many populations of migratory songbirds are declining or shifting in distribution. This is likely due to environmental changes that alter factors such as food availability that may have an impact on survival and/or breeding success. We tested the impact of experimentally supplemented food on the breeding success over three years of northern wheatears (Oenanthe oenanthe), a species in decline over much of Europe. The number of offspring fledged over the season was higher for food-supplemented birds than for control birds. The mechanisms for this effect were that food supplementation advanced breeding date, which, together with increased resources, allowed further breeding attempts. While food supplementation did not increase the clutch size, hatching success or number of chicks fledged per breeding attempt, it did increase chick size in one year of the study. The increased breeding success was greater for males than females; males could attempt to rear simultaneous broods with multiple females as well as attempting second broods, whereas females could only increase their breeding effort via second broods. Multiple brooding is rare in the study population, but this study demonstrates the potential for changes in food availability to affect wheatear breeding productivity, primarily via phenotypic flexibility in the number of breeding attempts. Our results have implications for our understanding of how wheatears may respond to natural changes in food availability due to climate changes or changes in habitat management

Home is where the heart rot is: violet click beetle, Limoniscus violaceus (Müller, 1821), habitat attributes and volatiles

The decreasing number of veteran trees in Europe threatens old‐growth habitats and the fauna they support. This includes rare taxa, such as the violet click beetle, Limoniscus violaceus (Müller, 1821). Samples of wood mould were taken from all beech trees in Windsor Forest previously confirmed to have contained L. violaceus larvae, and from trees where L. violaceus had not previously been detected, the latter categorised as having high, medium or low likelihood of containing the beetle during recent surveys. Habitat characteristics were measured, and volatile profiles determined using gas‐chromatography mass‐spectrometry. Water content significantly differed between tree hollows of different violet click beetle status, high‐potential habitats having higher and relatively stable water content compared with habitats with medium or low potential of beetle occupancy. Several volatile organic compounds (VOCs) were significantly associated with L. violaceus habitats. No differences in other characteristics were detected. The distinction in water regime between habitats highlights that recording this quantitatively could improve habitat surveys. Several potential L. violaceus attractant VOCs were identified. These could potentially be integrated into existing monitoring strategies, such as through volatile‐baited emergence traps or volatile‐based surveying of habitats, for more efficient population monitoring of the beetle

Research on the early implementation of Curriculum for Wales: Wave 2 report

This report presents findings of the second wave (Wave 2) of qualitative research with 62 senior leaders in schools and Pupil Referral Units (PRUs) carried out by Arad Research and the Open University in Wales. The aim of this research was to undertake two waves of qualitative research during academic year 2022/23 to understand how the curriculum and assessment reforms were working for practitioners and learners in schools and settings, and the barriers and facilitators to successful implementation. This report follows on from the Wave 1 report, which presented findings of the first round of interviews with senior leaders. In addition to presenting findings from follow-up interviews with senior leaders, it also presents evidence from fieldwork with groups of learners in primary and secondary schools, outlining their experiences of curriculum delivery during the academic year 2022/23

Research with schools on the early implementation of Curriculum for Wales: Wave 1 report

This report presents research conducted with schools on the early implementation of Curriculum for Wales. The research aims to undertake two waves of qualitative research during academic year 2022/23 to understand how the curriculum and assessment reforms are working for practitioners and learners in schools and settings, and the barriers and facilitators to successful implementation. The research informs the support that the Welsh Government and its partners are putting in place to maximise success. This report contains the findings of the first wave of qualitative research with 64 senior leaders in schools and Pupil Referral Units carried out on behalf of the Welsh Government between November 2022 to January 2023. A report detailing findings of a second wave of interviews with senior leaders, as well as fieldwork with learners, will be published later in 2023

Patterns of parasitism by Trybliographa rapae (Westw.), a cynipid parasitoid of the cabbage root fly.

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