• Energy Research

AbstractThe capacity to forecast the effects of climate change on biodiversity largely relies on identifying traits capturing mechanistic relationships with the environment through standardized field experiments distributed across relevant spatial scales. The effects of short‐term experimental manipulations on local communities may overlap with regional climate gradients that have been operating during longer time periods. However, to the best of our knowledge, there are no studies simultaneously assessing such long‐term macroecological drivers with local climate manipulations.We analysed this issue with springtails (Class Collembola), one of the dominant soil fauna groups, in a standardized climate manipulation experiment conducted across six European countries encompassing broad climate gradients. We combined community data (near 20K specimens classified into 102 species) with 22 eco‐morphological traits and reconstructed their phylogenetic relationships to track the evolution of adaptations to live at different soil depths, which is key to cope with desiccation. We then applied joint species distribution models to investigate the combined effect of the regional aridity gradient with the local experimental treatment (drought and warming) over the assembly of springtail communities and tested for significant trait–environment relationships mediating their community‐level responses.Our results show (1) a convergent evolution in all three major collembolan lineages of species adapted to inhabit at different soil strata; (2) a clear signature of aridity selecting traits of more epigeic species at a biogeographical scale and (3) the association of short‐term experimental drought with traits related to more euedaphic life‐forms.The hemiedaphic condition would be the plesiomorphic state for Collembola while the adaptations for an epigeic life would have been secondarily gained. Epigeic springtails are not only more resistant to drought, but also have a higher dispersal capacity that allows them to seek more favourable micro‐habitats after experiencing drier conditions. The observed relative edaphization of the springtail communities after short‐term experimental drought may thus be a transient community response.The disparity between macroecological trends and fast community‐level responses after climate manipulations highlights the need of simultaneously assessing long‐term and short‐term drivers at broad spatial scales to adequately interpret trait–environment relationships and better forecast biodiversity responses to climate change.Read the freePlain Language Summaryfor this article on the Journal blog.

Question: Can useful realised niche models be constructed for British plant species using climate, canopy height and mean Ellenberg indices as explanatory variables? Location: Great Britain. Methods: Generalised linear models were constructed using occurrence data covering all major natural and semi-natural vegetation types (n=40 683 quadrat samples). Paired species and soil records were only available for 4% of the training data (n=1033) so modelling was carried out in two stages. First, multiple regression was used to express mean Ellenberg values for moisture, pH and fertility, in terms of direct soil measurements. Next, species presence/absence was modelled using mean indicator scores, cover-weighted canopy height, three climate variables and interactions between these factors, but correcting for the presence of each target species in training plots to avoid circularity. Results: Eight hundred and three higher plants and 327 bryophytes were modelled. Thirteen per cent of the niche models for higher plants were tested against an independent survey dataset not used to build the models. Models performed better when predictions were based only on indices derived from the species composition of each plot rather than measured soil variables. This reflects the high variation in vegetation indices that was not explained by the measured soil variables. Conclusions: The models should be used to estimate expected habitat suitability rather than to predict species presence. Least uncertainty also attaches to their use as risk assessment and monitoring tools on nature reserves because they can be solved using mean environmental indicators calculated from the existing species composition, with or without climate data.

The global climate is predicted to become significantly warmer over the next century. This will affect ecosystem processes and the functioning of semi natural and natural ecosystems in many parts of the world. However, as various ecosystem processes may be affected to a different extent, balances between different ecosystem processes as well as between different ecosystems may shift and lead to major unpredicted changes. In this study four European shrubland ecosystems along a north-south temperature gradient were experimentally warmed by a novel nighttime warming technique. Biogeochemical cycling of both carbon and nitrogen was affected at the colder sites with increased carbon uptake for plant growth as well as increased carbon loss through soil respiration. Carbon uptake by plant growth was more sensitive to warming than expected from the temperature response across the sites while carbon loss through soil respiration reacted to warming in agreement with the overall Q10 and response functions to temperature across the sites. Opposite to carbon, the nitrogen mineralization was relatively insensitive to the temperature increase and was mainly affected by changes in soil moisture. The results suggest that C and N cycles respond asymmetrically to warming, which may lead to progressive nitrogen limitation and thereby acclimation in plant production. This further suggests that in many temperate zones nitrogen deposition has to be accounted for, not only with respect to the impact on water quality through increased nitrogen leaching where N deposition is high, but also in predictions of carbon sequestration in terrestrial ecosystems under future climatic conditions. Finally the results indicate that on the short term the above-ground processes are more sensitive to temperature changes than the below ground processes.

AbstractClimatic changes, including altered precipitation regimes, will affect key ecosystem processes, such as plant productivity and biodiversity for many terrestrial ecosystems. Past and ongoing precipitation experiments have been conducted to quantify these potential changes. An analysis of these experiments indicates that they have provided important information on how water regulates ecosystem processes. However, they do not adequately represent global biomes nor forecasted precipitation scenarios and their potential contribution to advance our understanding of ecosystem responses to precipitation changes is therefore limited, as is their potential value for the development and testing of ecosystem models. This highlights the need for new precipitation experiments in biomes and ambient climatic conditions hitherto poorly studied applying relevant complex scenarios including changes in precipitation frequency and amplitude, seasonality, extremity and interactions with other global change drivers. A systematic and holistic approach to investigate how soil and plant community characteristics change with altered precipitation regimes and the consequent effects on ecosystem processes and functioning within these experiments will greatly increase their value to the climate change and ecosystem research communities. Experiments should specifically test how changes in precipitation leading to exceedance of biological thresholds affect ecosystem resilience and acclimation.

Natural capital and ecosystem service concepts are embodied in the ecosystems approach to sustainable development, which is a framework being consistently adopted by decision making bodies ranging from national governments to the United Nations. In the Millennium Ecosystem Assessment soils are given the vital role of a supporting service, but many of the other soil goods and services remain obscured. In this review we address this using and earth-system approach, highlighting the final goods and services soils produce, in a stock-fund, fund-service model of the pedosphere. We also argue that focusing on final goods and services will be counterproductive in the long run and emphasize that final goods and services are derived from an ecosystem supply chain that relies on ecological infrastructure. We propose that an appropriate ecosystems framework for soils should incorporate soil stocks (natural capital) showing their contribution to stock-flows and emergent fund-services as part of the supply chain. By so doing, an operational ecosystems concept for soils can draw on much more supporting data on soil stocks as demonstrated in a case study with soils data from England and Wales showing stocks, gaps in monitoring and drivers of change. Although the focus of this review is on soils, we believe the earth-system approach and principles of the ecosystem supply chain are widely applicable to the ecosystems approach and bring clarity in terms of where goods and services are derived from.

Measuring and modelling the efflux of greenhouse gases from soils is crucial for gauging ecosystem responses to climate and land-use change, and potential contributions and feedbacks to gas emissions. Upland soils with high amounts of organic matter can produce large effluxes of CH4 and potentially N2O, and therefore understanding the sensitivity of such fluxes to changes in climate (e.g. temperature) is of importance. Here we consider the role of shallow podzols in the temperature response of CH4 and N2O efflux using a simple laboratory incubation. Such soils have a shallow peat layer overlain by coarse organic matter, and by splitting and incubating these layers across a 1-30 degrees C temperature ramp, we observed a significant negative temperature response for both gases, and a gas-dependent effect on the presence of a between-layer difference. Given these observations, there is a need to consider the temperature sensitivity of near surface layers as distinct, and to recognise the potential for shallow podzols to have a strong source sink transition across temperature ranges. (C) 2013 Elsevier Ltd. All rights reserved.

Water-borne pathogen contamination from untreated sewage effluent and runoff from farms is a serious threat to the use of river water for drinking and commercial purposes, such as downstream estuarine shellfish industries. In this study, the impact of climate change and land-use change on the presence of faecal indicator bacteria in freshwater was evaluated, through the use of a recently-developed catchment-scale pathogen model. The River Conwy in Wales has been used as a case-study, because of the large presence of livestock in the catchment and the importance of the shellfish harvesting activities in its estuary. The INCA-Pathogens catchment model has been calibrated through the use of a Monte-Carlo-based technique, based on faecal indicator bacteria measurements, and then driven by an ensemble of climate projections obtained from the HadRM3-PPE model (Future Flow Climate) plus four land-use scenarios (current land use, managed ecosystem, abandonment and agricultural intensification). The results show that climate change is not expected to have a very large impact on average river flow, although it might alter its seasonality. The abundance of faecal indicator bacteria is expected to decrease in response to climate change, especially during the summer months, due to reduced precipitation, causing reduced runoff, and increased temperature, which enhances the bacterial die-off processes. Land-use change can also have a potentially large impact on pathogens. The “managed ecosystems” scenario proposed in this study can cause a reduction of 15% in average water faecal indicator bacteria and up to 30% in the 90th percentile of water faecal indicator bacteria, mainly due to the conversion of pasture land into grassland and the expansion of forest land. This study provides an example of how to assess the impacts of human interventions on the landscape, and what may be the extent of their effects, for other catchments where the human use of the natural resources in the uplands can jeopardise the use of natural resources downstream.