ABSTRACT: Active stomatal regulation is a good trait for limiting water losses during mild droughts in temperate climates to minimise any loss of biomass production. A thermal camera detects differences in leaf temperatures. If they are lower than air temperature there is evidence for high conductance, e.g. high evapotranspiration. If leaf temperatures are higher, then this is evidence for low conductance, e.g. stomatal regulation. We conducted two independent drought stress experiments with the C3 grass perennial ryegrass and C4 Miscanthus spp. accessions. Drought impacted perennial ryegrass early on upon stress exposure before any visible senescence or wilting of leaves was observed. The impact of drought on stomatal conductance in Miscanthus was six weeks later than in perennial ryegrass, although the eventual impact of drought on water use efficiency (WUE) was greater in Miscanthus than in perennial ryegrass. In perennial ryegrass a correlation between the index of stomatal conductance ( I G) values obtained from thermal images and stomatal conductance ( g s) measured using porometry was found. In Miscanthus , this correlation was weaker but still significant. In Miscanthus , biomass accumulation was affected by both genotype and drought treatment. We have described an approach to phenotyping of grass species that could be easily scaled-up for application in large-scale screening and crop-breeding programmes. This approach entails a rapid, non-invasive, means of obtaining information about leaf physiology, combined with monitoring of resource use allowing an integrated measure of water resource use efficiency.
ABSTRACT: Paropsisterna selmani, a leaf beetle native to Tasmania, has recently established in Ireland and the UK, where it is considered an emerging defoliator of plantation eucalypts. Despite its pest potential, little is known about its genetic diversity or invasion history. A preliminary analysis was conducted of mitochondrial cytochrome oxidase I (COI) sequence variation in 83 individuals from 10 populations across Ireland, the UK and Tasmania. Seventeen haplotypes were identified, with low haplotype and nucleotide diversity observed in Ireland, higher diversity in Tasmania, and unique haplotypes in the UK population. A dominant haplotype (H1) was shared between Ireland and Tasmania but was absent from the UK. Phylogenetic and haplotype network analyses suggest shallow divergence among most haplotypes, consistent with a recent introduction. Due to limited within-site replication and reliance on a single mitochondrial marker, results are interpreted cautiously. This study provides baseline genetic data for P. selmani in Europe and highlights the need for broader sampling and multi-locus approaches to clarify invasion pathways and support management efforts.
Special areas of conservation (SAC) are designated areas established to protect important habitats and species. However, effective management and monitoring of these SACs is required in order to confirm they are working as intended. Marine surveys can be expensive, as well as dependent on weather, making them labour-intensive methods of monitoring species. Here, we conducted eDNA metabarcoding in the Blasket Island SAC in order to build a preliminary repository baseline of the vertebrate species present. Our results detected 23 taxa across different trophic levels, demonstrating the utility of this technique as a relatively quick, cost-effective and non-invasive tool for detecting species in a protected marine environment.
Lough Neagh is the largest freshwater lake (392km2) in Ireland and Britain, providing drinking water to 40% of Northern Ireland's population. Recently, however, it has been described as 'dying', due mainly to the effects of nutrients enabling eutrophication by blue-green algae. Solutions have been proposed to reduce runoff, but there has been limited discussion of establishing the equivalent of the diverse native woodlands that once existed and protected its catchment, particularly in the buffer zones adjacent to waterways. With a focus on woodland history, we present here the pollen record of a lake sediment core obtained from the deepest part of Lough Neagh. This provides a vegetation history spanning the period from open tundra grassland and sedge-rich habitats at the end of the last glaciation, through to mixed woodlands of broadleaves and conifers in the early and mid-Holocene. In the late Holocene, the landscape was converted to grassland, heath and peatland communities, largely due to increasing human impact. An abundance of the green alga Pediastrum clearly indicates nutrients entering the lake when the vegetation cover is limited and the landscape vulnerable to erosion. This is both prior to natural colonisation by woodlands and increasingly as the extensive mixed woodlands were cleared for agriculture, demonstrating the importance of woodland cover for reducing runoff. It is suggested that more emphasis be placed on facilitating the reestablishment of Atlantic woodlands as nature-based solutions to provide resilient watersheds, capable of mitigating future warming and extreme events.
The European or common ash (Fraxinus excelsior), which is native to the island of Ireland, has significant cultural, economic and environmental value. The species is currently being devastated by the invasive ascomycete pathogen Hymenoscyphus fraxineus. Managing H. fraxineus inoculum levels can protect important ash trees and stands by reducing disease inoculum and the spread of the pathogen. The aim of this research was to compare treatments for reducing H. fraxineus inoculum by disrupting sexual sporulation (apothecia and ascospore production). Three treatments (sheep grazing, tree thinning and urea application) were investigated at ash plantations located in County Armagh and in County Kildare. Although none of the treatments affected H. fraxineus ascospore production, sheep grazing significantly reduced the formation of large and medium sized apothecia at the field site in County Kildare. Sheep grazing also influenced the forest floor microclimate at this field site. In addition, our laboratory studies support previous evidence that H. fraxineus requires light and humidity for apothecia production. Therefore, manipulating the microclimate of ash stands might help manage H. fraxineus sexual sporulation. Further investigations into grazing and thinning, coupled with approaches such as the use of potentially tolerant ash populations, could mitigate the impact of H. fraxineus on F. excelsior.
