Carol Palmer

Changing leaf nitrogen and canopy height quantify processes leading to plant and butterfly diversity loss in agricultural landscapes

Summary We describe a novel method for quantifying ecosystem drivers that potentially compromise the effectiveness of agri-environment schemes. We use three sources of data that for many countries are already in the public domain: governmental agricultural statistics, which provide a quantitative assessment of farming intensity in the ‘working landscape’, data on threat status and species distribution for plants and butterflies from conservation agencies and similar bodies and functional traits of plant species abstracted from published data bases. Changes in land use alter ecosystem processes which in turn modify both biodiversity and representation of functional types at the landscape scale. We interpret functional shifts to quantify important ecological drivers of floristic and faunal change and their causal land use origins. We illustrate the power of this approach by means of a worked example. We demonstrate that despite conservation policies to counteract them, eutrophication, identified by leaf nitrogen content, and abandonment, correlated with plant canopy height, are still causing biodiversity loss to native higher plants and butterflies in the English countryside. We use our analyses to suggest how conservation policies can be made more effective and discuss how similar approaches could be applied elsewhere.

The triangular seed mass-leaf area relationship holds for annual plants and is determined by habitat productivity

Summary Plant allometries help us to understand resource allocation in plants and provide insight into how communities are structured. For woody species, a triangular allometric relationship between seed size and leaf size occurs in which all combinations are all possible, except for species with big seeds and small leaves (Cornelissen 1999). This relationship is thought to be a consequence of between habitat variation in abiotic conditions. In this study, we tested if the triangular relationship between seed mass and leaf area holds for annual species, and if variation in soil productivity and light (measured as Ellenberg indicator values: EIVs) are driving this relationship. We show that the triangular relationship also holds for annuals, which suggests that the allometric combinations between leaf area and seed mass are conserved across life-forms. The triangular relationship was driven by between-habitat variation in soil productivity. This means that as soil productivity increases, plants with bigger leaves could have either big or small seeds. However, in low soil productivity habitats, plants are constrained in their options, and plants with small leaves can only have small seeds. This article is protected by copyright. All rights reserved.

An early to Middle Saxon settlement at Quarrington, Lincolnshire

Excavations undertaken at Quarrington, near Sleaford, Lincolnshire, revealed part of an Early and Middle Saxon settlement with associated fields or enclosures. Several timber buildings were identified, both round and rectangular, and there was evidence of ferrous and non-ferrous metalworking at the site. Finds included a large and regionally significant pottery assemblage, showing that Quarrington had an extensive trading network and obtained pottery from Lincolnshire and Leicestershire in the Early Saxon period. Pottery from the Northamptonshire area dominated the assemblage in the Middle Saxon period, with a smaller component from Lincolnshire and a limited quantity from Ipswich. Spatial variations in the Saxon ceramic assemblage suggest that the focus of settlement shifted towards the west or north west in the Middle Saxon period. Few rural sites of Early and Middle Saxon date have produced sufficient faunal material to permit an analysis of changes during the fifth to eighth centuries until now; the large bone assemblage from Quarrington indicates changes in diet and the husbandry of domestic animals through time, with sheep becoming more important as pig diminished. Alterations to the slaughter profiles of cattle and sheep were also evident and may indicate changes from subsistence to surplus production. An apparently isolated Neolithic cremation and a post-medieval stone building were also revealed.