Aidan M. Keith

Exploring the ecological constraints to multiple ecosystem service delivery and biodiversity

1. Understanding and quantifying constraints to multiple ecosystem service delivery and biodiversity is vital for developing management strategies for current and future human well-being. A particular challenge is to reconcile demand for increased food production with provision of other ecosystem services and biodiversity. 2. Using a spatially extensive data base (covering Great Britain) of co-located biophysical measurements (collected in the Countryside Survey), we explore the relationships between ecosystem service indicators and biodiversity across a temperate ecosystem productivity gradient. 3. Each service indicator has an individual response curve demonstrating that simultaneous analysis of multiple ecosystem services is essential for optimal service management. The shape of the response curve can be used to indicate whether ‘land sharing’ (provision of multiple services from the same land parcel) or ‘land sparing’ (single service prioritization) is the most appropriate option. 4. Soil carbon storage and above-ground net primary production indicators were found to define opposing ends of a primary gradient in service provision. Biodiversity and water quality indicators were highest at intermediate levels of both factors, consistent with a unimodal relationship along a productivity gradient. 5. Positive relationships occurred between multiple components of biodiversity, measured as taxon richness of all plants, bee and butterfly nectar plants, soil invertebrates and freshwater macroinvertebrates, indicating potential for management measures directed at one aspect of biodiversity to deliver wider ecosystem biodiversity. 6. We demonstrate that in temperate, human-dominated landscapes, ecosystem services are highly constrained by a fundamental productivity gradient. There are immediate trade-offs between productivity and soil carbon storage but potential synergies with services with different shaped relationships to production. 7. Synthesis and applications. Using techniques such as response curves to analyse multiple service interactions can inform the development of Spatial Decision Support tools and landscape-scale ecosystem service management options. At intermediate productivity, ‘land-sharing’ would optimize multiple services, however, to deliver significant soil carbon storage ‘land-sparing’ is required, that is, resources focused in low productivity areas with high carbon to maximize investment return. This study emphasizes that targets for services per unit area need to be set within the context of the national gradients reported here to ensure best use of limited resources.

Interactions between the hemiparasitic angiospermRhinanthus minor and its hosts: From the cell to the ecosystem

Parasitic plants can significantly influence the species to which they attach. The host response is variable however, and ranges from death of the host to no detectable effects in terms of both growth and physiology. The parasite can directly influence its hosts through resource abstraction, and indirectly by influencing inter- and intra-specific interactions. Abiotic factors interact with these direct and indirect effects to moderate the potential outcome of the host parasite interaction. This paper sets out to review a series of experiments that have been undertaken in our laboratory over a number of years that examine these effects and help us to understand mechanisms underpinning the variability in host response.

Land-use and land-management change: relationships with earthworm and fungi communities and soil structural properties

BackgroundChange in land use and management can impact massively on soil ecosystems. Ecosystem engineers and other functional biodiversity in soils can be influenced directly by such change and this in turn can affect key soil functions. Here, we employ meta-analysis to provide a quantitative assessment of the effects of changes in land use and land management across a range of successional/extensification transitions (conventional arable → no or reduced tillage → grassland → wooded land) on community metrics for two functionally important soil taxa, earthworms and fungi. An analysis of the relationships between community change and soil structural properties was also included.ResultsMeta-analysis highlighted a consistent trend of increased earthworm and fungal community abundances and complexity following transitions to lower intensity and later successional land uses. The greatest changes were seen for early stage transitions, such as introduction of reduced tillage regimes and conversion to grassland from arable land. Not all changes, however, result in positive effects on the assessed community metrics. For example, whether woodland conversion positively or negatively affects community size and complexity depends on woodland type and, potentially, the changes in soil properties, such as pH, that may occur during conversion. Alterations in soil communities tended to facilitate subsequent changes in soil structure and hydrology. For example, increasing earthworm abundances and functional group composition were shown to be positively correlated with water infiltration rate (dependent on tillage regime and habitat characteristics); while positive changes in fungal biomass measures were positively associated with soil microaggregate stability.ConclusionsThese findings raise the potential to manage landscapes to increase ecosystem service provision from soil biota in relation to regulation of soil structure and water flow.

Implications of land-use change to Short Rotation Forestry in Great Britain for soil and biomass carbon

Land‐use change can have significant impacts on soil and aboveground carbon (C) stocks and there is a clear need to identify sustainable land uses which maximize C mitigation potential. Land‐use transitions from agricultural to bioenergy crops are increasingly common in Europe with one option being Short Rotation Forestry (SRF). Research on the impact on C stocks of the establishment of SRF is limited, but given the potential for this bioenergy crop in temperate climates, there is an evident knowledge gap. Here, we examine changes in soil C stock following the establishment of SRF using combined short (30 cm depth) and deep (1 m depth) soil cores at 11 sites representing 29 transitions from agriculture to SRF. We compare the effects of tree species including 9 coniferous, 16 broadleaved and 4 Eucalyptus transitions. SRF aboveground and root biomass were also estimated in 15 of the transitions using tree mensuration data allowing assessments of changes in total ecosystem C stock. Planting coniferous SRF, compared to broadleaved and Eucalyptus SRF, resulted in greater accumulation of litter and overall increased soil C stock relative to agricultural controls. Though broadleaved SRF had no overall effect on soil C stock, it showed the most variable response suggesting species‐specific effects and interactions with soil types. While Eucalyptus transitions induced a reduction in soil C stocks, this was not significant unless considered on a soil mass basis. Given the relatively young age and limited number of Eucalyptus plantations, it is not possible to say whether this reduction will persist in older stands. Combining estimates of C stocks from different ecosystem components (e.g., soil, aboveground biomass) reinforced the accumulation of C under coniferous SRF, and indicates generally positive effects of SRF on whole‐ecosystem C. These results fill an important knowledge gap and provide data for modelling of future scenarios of LUC.

Spatial patterns and environmental constraints on ecosystem services at a catchment scale.

Improved understanding and prediction of the fundamental environmental controls on ecosystem service supply across the landscape will help to inform decisions made by policy makers and land-water managers. To evaluate this issue for a local catchment case study, we explored metrics and spatial patterns of service supply for water quality regulation, agriculture production, carbon storage, and biodiversity for the Macronutrient Conwy catchment. Methods included using ecosystem models such as LUCI and JULES, integration of national scale field survey datasets, earth observation products and plant trait databases, to produce finely resolved maps of species richness and primary production. Analyses were done with both 1×1km gridded and subcatchment data. A common single gradient characterised catchment scale ecosystem services supply with agricultural production and carbon storage at opposing ends of the gradient as reported for a national-scale assessment. Species diversity was positively related to production due to the below national average productivity levels in the Conwy combined with the unimodal relationship between biodiversity and productivity at the national scale. In contrast to the national scale assessment, a strong reduction in water quality as production increased was observed in these low productive systems. Various soil variables were tested for their predictive power of ecosystem service supply. Soil carbon, nitrogen, their ratio and soil pH all had double the power of rainfall and altitude, each explaining around 45% of variation but soil pH is proposed as a potential metric for ecosystem service supply potential as it is a simple and practical metric which can be carried out in the field with crowd-sourcing technologies now available. The study emphasises the importance of considering multiple ecosystem services together due to the complexity of covariation at local and national scales, and the benefits of exploiting a wide range of metrics for each service to enhance data robustness.

Initial soil C and land use history determine soil C sequestration under perennial bioenergy crops

In the UK and other temperate regions, short rotation coppice (SRC) and Miscanthus x giganteus (Miscanthus) are two of the leading ‘second‐generation’ bioenergy crops. Grown specifically as a low‐carbon (C) fossil fuel replacement, calculations of the climate mitigation provided by these bioenergy crops rely on accurate data. There are concerns that uncertainty about impacts on soil C stocks of transitions from current agricultural land use to these bioenergy crops could lead to either an under‐ or overestimate of their climate mitigation potential. Here, for locations across mainland Great Britain (GB), a paired‐site approach and a combination of 30‐cm‐ and 1‐m‐deep soil sampling were used to quantify impacts of bioenergy land‐use transitions on soil C stocks in 41 commercial land‐use transitions; 12 arable to SRC, 9 grasslands to SRC, 11 arable to Miscanthus and 9 grasslands to Miscanthus. Mean soil C stocks were lower under both bioenergy crops than under the grassland controls but only significant at 0–30 cm. Mean soil C stocks at 0–30 cm were 33.55 ± 7.52 Mg C ha−1 and 26.83 ± 8.08 Mg C ha−1 lower under SRC (P = 0.004) and Miscanthus plantations (P = 0.001), respectively. Differences between bioenergy crops and arable controls were not significant in either the 30‐cm or 1‐m soil cores and smaller than for transitions from grassland. No correlation was detected between change in soil C stock and bioenergy crop age (time since establishment) or soil texture. Change in soil C stock was, however, negatively correlated with the soil C stock in the original land use. We suggest, therefore, that selection of sites for bioenergy crop establishment with lower soil C stocks, most often under arable land use, is the most likely to result in increased soil C stocks.

Evaluation of the ECOSSE model for simulating soil carbon under short rotation forestry energy crops in Britain

Understanding and predicting the effects of land‐use change to short rotation forestry (SRF) on soil carbon (C) is an important requirement for fully assessing the C mitigation potential of SRF as a bioenergy crop. There is little current knowledge of SRF in the UK and in particular a lack of consistent measured data sets on the direct impacts of land use change on soil C stocks. The ECOSSE model was developed to simulate soil C dynamics and greenhouse gas (GHG) emissions in mineral and organic soils. The ECOSSE model has already been applied spatially to simulate land‐use change impacts on soil C and GHG emissions. However, it has not been extensively evaluated under SRF. Eleven sites comprising 29 transitions in Britain, representing land‐use change from nonwoodland land uses to SRF, were selected to evaluate the performance of ECOSSE in predicting soil C and soil C change in SRF plantations. The modelled C under SRF showed a strong correlation with the soil C measurements at both 0–30 cm (R = 0.93) and 0–100 cm soil depth (R = 0.82). As for the SRF plots, the soil C at the reference sites have been accurately simulated by the model. The extremely high correlation for the reference fields (R ≥ 0.99) shows a good performance of the model spin‐up. The statistical analysis of the model performance to simulate soil C and soil C changes after land‐use change to SRF highlighted the absence of significant error between modelled and measured values as well as the absence of significant bias in the model. Overall, this evaluation reinforces previous studies on the ability of ECOSSE to simulate soil C and emphasize its accuracy to simulate soil C under SRF plantations.

Evaluation of the ECOSSE model for simulating soil organic carbon under Miscanthus and short rotation coppice-willow crops in Britain

In this paper, we focus on the impact on soil organic carbon (SOC) of two dedicated energy crops: perennial grass Miscanthus x Giganteus (Miscanthus) and short rotation coppice (SRC)‐willow. The amount of SOC sequestered in the soil is a function of site‐specific factors including soil texture, management practices, initial SOC levels and climate; for these reasons, both losses and gains in SOC were observed in previous Miscanthus and SRC‐willow studies. The ECOSSE model was developed to simulate soil C dynamics and greenhouse gas emissions in mineral and organic soils. The performance of ECOSSE has already been tested at site level to simulate the impacts of land‐use change to short rotation forestry (SRF) on SOC. However, it has not been extensively evaluated under other bioenergy plantations, such as Miscanthus and SRC‐willow. Twenty‐nine locations in the United Kingdom, comprising 19 paired transitions to SRC‐willow and 20 paired transitions to Miscanthus, were selected to evaluate the performance of ECOSSE in predicting SOC and SOC change from conventional systems (arable and grassland) to these selected bioenergy crops. The results of the present work revealed a strong correlation between modelled and measured SOC and SOC change after transition to Miscanthus and SRC‐willow plantations, at two soil depths (0–30 and 0–100 cm), as well as the absence of significant bias in the model. Moreover, model error was within (i.e. not significantly larger than) the measurement error. The high degrees of association and coincidence with measured SOC under Miscanthus and SRC‐willow plantations in the United Kingdom, provide confidence in using this process‐based model for quantitatively predicting the impacts of future land use on SOC, at site level as well as at national level.

Chapter 3:Soil Natural Capital and Ecosystem Service Delivery in a World of Global Soil Change

Society exploits nature to produce goods and services that are of benefit to our individual and societal well-being, food being a primary example of nature’s provision. Supporting this is the thin layer of soil that envelopes the earth, lying between us, our prosperity and certain starvation. Stewar...

Predatory soil nematodes (Nematoda: Mononchida) in major land-use types across Ireland

The distribution of predatory soil nematodes (Mononchida) across Europe is well described. However, in Ireland knowledge of mononchids is limited to a single study. The CréBeo project was the first systematic survey of soil biodiversity in the major land-use types across the Republic of Ireland. Nematodes were sampled from 61 locations with an extensive geographical spread including arable, pasture, broadleaf forest, coniferous plantation, rough grazing and peatland sites. This study resulted in 11 first records of mononchid species from Ireland (of which 2 are new records for Britain and Ireland). We discuss the mononchid species found and aspects of their distribution across major land uses.