Conserving socio-ecological landscapes: An analysis of traditional and responsive management practices for floodplain meadows in England

Contemporary practice in the conservation of socio-ecological landscapes draws on both a model of responsive management, and also on ideas about historic management. This study considered what evidence might exist for the exercise of these approaches to management in the conservation of floodplain meadows in England, in order to inform understanding and knowledge of conservation management and assessment practice. Evidence for a model of responsive management was limited, with managing stakeholders often alternating between this model and an alternative approach, called here the ‘traditional management approach’, based on ideas, narratives and prescriptions of long-established land management practices. Limited monitoring and assessment appeared to undermine the former model, whilst uncertainty over past long-standing management practices undermined the latter. As a result of the relative power of conservation actors over farmers delivering site management, and their framings of meadows as ‘natural’ spaces, management tended to oscillate between aspects of these two approaches in a sometimes inconsistent manner. Conservation managers should consider the past motivating drivers and management practices that created the landscapes they wish to conserve, and bear in mind that these are necessarily implicated in aspects of the contemporary landscape value that they wish to maintain. They should ensure that assessment activity captures a broad range of indicators of site value and condition, not only biological composition, and also record data on site management operations in order to ensure management effectiveness

The sensing of drying soil by roots, and the involvement of abscisic acid as a signal

SIGLEAvailable from British Library Document Supply Centre- DSC:DX174103 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Soil aeration status in a lowland wet grassland

The maintenance or development of plant community diversity in species-rich wet grasslands has been a focus of water management considerations in the UK for the past 20 years. Much attention has been given to the control of water levels in the ditch systems within these wet grassland systems. In this paper we report measurements of aeration status and water-table fluctuation made on a peat soil site at Tadham Moor in Somerset, UK, where water management has focused on the maintenance of wet conditions that often result in flooding in winter and wet soil conditions in the spring and summer. Measurement and modelling of the water-table fluctuation indicates the possibility of variability in the aeration of the root environment and anoxic conditions for much of the winter period and for part of the spring and summer. We have used water content and redox potential measurements to characterize the aeration status of the peat soil. We find that air-filled porosity is related to water-table depth in these situations. Redox potentials in the spring were generally found to be low, implying a reducing condition for nitrate and iron. A significant relationship (p < 0·01) between redox potential and water-table depth exists for data measured at 0·1 m depth, but no relationship could be found for data from 0·4 m depth. Copyright © 2004 John Wiley & Sons, Ltd

Use of effective stress to predict the penetrometer resistance of unsaturated agricultural soils

One of the most important functions of soil is to provide an environment for root growth. Ideally, roots will elongate with minimal impedance and acquire water and nutrients so that crops may grow to their full potential. In practice, physical stresses in the root environment restrict root growth: one of the most commonly-cited physical stresses that affect root growth is “mechanical impedance”. When soils are strong, because they are compact or dry, roots elongate more slowly and this in turn has a detrimental effect on plant growth. In this paper, we examine the relative importance of compaction and soil drying as factors that lead to strong soil. We measured soil strength with both a tensile test and a penetrometer. We compared pressures of rotating and fixed (non-rotating) penetrometers. The utility of the rotating penetrometer is that it is thought to give a resistance to penetration similar to that experienced by elongating plant roots. For three soils, we confirmed published work reporting that effective stress can be used to define a relationship between tensile strength and soil water status that is common for a range of soils. Then, for loamy sand and silty clay loam soils at two dry bulk densities, we considered the relationship between penetrometer pressure and effective stress at matric potentials greater than −100 kPa. We found that for both soils, penetrometer pressure increased with effective stress and for the loamy sand, but not the silty clay loam soil, penetrometer pressure increased with density for a given effective stress. To examine the relationship between soil density and effective stress more fully, we measured the penetrometer pressures of five soils at two densities following equilibration at −100 kPa. We suggest that effective stress can be used to predict penetrometer pressure (provided the soil is compressible) and therefore the resistance to root penetration offered by the soil. Rotation decreased penetrometer pressure in the soils tested. Data obtained from the rotating penetrometer suggests that relatively moist soils (matric potential as high as −100 kPa) can provide high mechanical impedance to root elongation

Stomatal control by both ABA in the xylem sap and leaf water status : a test of a model for droughted or ABA-fed field-grown maize

International audienc

Impact of nitrogen deposition on the species richness of grasslands

A transect of 68 acid grasslands across Great Britain, covering the lower range of ambient annual nitrogen deposition in the industrialized world (5 to 35 kg Nha–1 year–1), indicates that long-term, chronic nitrogen deposition has significantly reduced plant species richness. Species richness declines as a linear function of the rate of inorganic nitrogen deposition, with a reduction of one species per 4-m2 quadrat for every 2.5 kg Nha–1 year–1 of chronic nitrogen deposition. Species adapted to infertile conditions are systematically reduced at high nitrogen deposition. At the mean chronic nitrogen deposition rate of central Europe (17 kg Nha–1 year–1), there is a 23% species reduction compared with grasslands receiving the lowest levels of nitrogen deposition

Does soil strength play a role in wheat yield losses caused by soil drying?

Shoot growth in wheat is sensitive to high soil strength, but as high strength and drying tend to occur together it has proved difficult to separate the effects of water stress and mechanical impedance. The results of two field experiments in 2003 and 2004, where soil strength was manipulated by compaction and irrigation, demonstrated that the yield of wheat (Triticum aestivum L.) was sensitive to physical stress in the root zone. We obtained linear relationships between yield and soil strength and between yield and accumulated soil moisture data (accumulation analogous to thermal time), with similar slopes for both seasons. We were unable to detect root-sourced signals of xylem-sap ABA concentration, despite changes in stomatal conductance. When mechanical impedance and matric potential were varied independently in controlled environments, the growth of wheat was sensitive to mechanical impedance, but not to small changes in matric potential. While the response of stomatal conductance to soil drying in the field could be interpreted as evidence of hydraulic signalling, we suggest that the role of high soil strength, in limiting growth rates on moderately dry soil, requires further research

A framework for the assessment of ecosystem goods and services; a case study on lowland floodplains in England

The rural space is increasingly valued for the multiple ecosystem services that it can deliver. For example, priorities in many lowland floodplains in England have changed in recent years from a focus on agricultural production towards environmental quality and the management of flood risk, in part linked to climate change. Recent concerns about food security, however, may reinstate the importance of agricultural production in these fertile areas. This paper explores changes in rural land use in floodplains by measuring the range of ecosystem services provided under different management scenarios. Generic land use scenarios consider management options that focus on single objectives, such as maximising agricultural production, maximising biodiversity and maximising flood storage capacity. Indicators are developed to value the ecosystem services provided by floodplains under each scenario, identifying potential synergy and conflict. This integrated ecosystems approach can help to inform future policy and practice for floodplain management, hopefully in ways that appeal to key stakeholders