Urban Pressure Research Articles

Effect of land use change on carbon stocks in an agricultural region of southern Benin

AbstractLand use change is one of the most important determinants of carbon storage and dynamics in ecosystems. Areas in the proximity of metropoles undergo land use changes but are poorly studied for their soil and biomass carbon budget, especially in Africa. Close to Benin's economic capital, the Lama Territory located on the Allada Plateau and is subject to high demographic and urbanization pressures. Carbon (C) stocks in the region are likely to be rapidly changing. This research assessed the land use changes and quantified the spatial distribution and variation of C stocks between 2000 and 2018 on the Ferralsols of the study area. Random forest models using spectral bands of LANDSAT images and some spectral indices as predictors were calibrated to classify the land use. C stocks of four C pools (aboveground, belowground biomass, litter, and soil) were mapped with InVEST (integrated valuation of ecosystem services and tradeoffs) model. Land use change occurred in 61% of the Ferralsol area between 2000 and 2018. The surface of forests and crop‐plantation associations decreased in benefit of tree plantations, adult palm groves, and built‐up areas. With the loss of forest surface and the increasing urbanization, C stocks of the region decreased by −218 Gg C with 4% uncertainty (−175 Gg C in soil pools, and − 125 Gg C in aboveground biomass with both 6% uncertainty) between 2000 and 2018. Results highlight: (i) the need for soil C stock accounting to avoid underestimation of C stocks evolution in a rural region; and (ii) the relevance of tree plantations and deforestation control to maintain the C stocks in tropical areas.

Why local is not enough! Constrains for adaptive governance in peri-urban areas. A case study in Mexico City

The current state of conceptual approaches to study peri-urban areas focusses foremost on land use changes and informal human settlements because of cities' urban expansion. The uncertainty and insecurity related to the expansion of the metropolis increases the complexity of the harmonization of institutional systems and the integration of local actors and communities to respond to urban planning processes. We address the calls for an examination of local community involvement in governance processes in Milpa Alta (MA), a peri-urban agricultural area in Mexico City (CDMX), a megacity with strong peri-urbanization trends. Livelihoods and adaptive capacities approaches were applied for analysis of the results of surveys, interviews, and participatory workshops. We report that in MA there is no integral adaptive capacity to deal with the effects of urban pressures, regional environmental deterioration, and local agricultural dynamics. There are close linkages between limited participation, low local organizational levels, and the social commitment of the population dedicated to agriculture and the existing distrust of government institutions. Sustainable management of peri-urban areas requires the creation of collaborative networks from which local institutional norms can emerge. Furthermore, peri-urban areas require the establishment of participatory systems for decision-making, including the recovery of community and local councils, to activate processes supportive of achieving peri-urban adaptive governance. We conclude that “local is not enough,” based on an adaptive governance approach, to understand the paradigms of decision-making processes and public and local interests in resource management for agriculture in this peri-urban case study.

Assessment of urban river water quality using modified NSF water quality index model at Siliguri city, West Bengal, India

Rivers are the source of freshwater for any urban community and hence, monitoring of river water is an obligatory yet challenging task. This study was conducted in a subtropical urban river in India with the view of developing a quantitative approach to assess its water quality (WQ) status. For the purposes of this study, water samples were collected from five locations across the Mahananda River main streams encompassing both urbanised and non-urbanised parts of the Siliguri city during April to June of 2021 and collected samples were analysed for fourteen common WQ indicators: pH, Temperature, Conductivity, TDS, Turbidity, Total Hardness (TH), DO, BOD, COD, NO 3 − , PO 4 3− , Cl − , Fecal Coliform (FC) and E. coli for assessing water quality. In order to obtain WQ status, the present study utilised the modified national sanitation foundation (NSF) water quality index (WQI) model, whereas the crucial WQ indicators were identified using the principal components analysis (PCA) technique. All WQ indicators were considered to compute the NSF-WQI except water pH and TH. Most WQ indicators were breached the guideline values of the Bureau of Indian Standards (BIS) and Indian Standards (IS) for surface water. The modified NSF-WQI results revealed that the Mahananda River water quality was “good” to “medium” quality and the water is only suitable for limited purposes under certain conditions. The findings of this study provided evidence that the river WQ is heavily influenced by urban pressures because relatively “good” WQ was found at the sampling location of the outer part of the urban area. The results of this research could be effective in improving the Mahananda River's water quality and maintaining its complex ecosystem in order to ensure sustainable urban growth.

Poliitilised ökoloogiad ja antropotseen urbaansuse pingeväljade maastikes

This article approaches complex relationships between disturbance-based ecologies and processes of urbanisation by focusing on urban fringes and valuation of life-forms within landscapes. The thematic discussion is inspired by changes of the Paljassaare Peninsula in Tallinn, which motivated the author to analytically assemble historical layers, ecological imaginations, and stories of planetary affects. The fieldwork related to the article’s argumentation is mainly based on the ethnographic method bringing together observations, interviews, and thematic narratives. The study indicates that disturbances and non-humans/birds become part of the landscape as intertwined materiality and perceiving-with, which involve tensions between presence and absence, and also tensions between past and future. The environment is not a passive “stage” in the process, but appears through emotional landscapes by creating relations between humans and non-humans. Transboundary flight trajectories of birds widen the perspective on earth-bound connections in urban space and make to rethink ways of co-existing. Urban landscapes linked to the sea accumulate diverse disturbances and ruptures, and their effects can be conflicting and interpretations change in time. The current study reveals tension fields and partial continuity of processes in which the Soviet-era legacy forms just one part in the complex assemblage. The border zone and the closed military-industrial complex in Tallinn coastal terrain generated conditions for disturbance-based ecologies, which have significantly influenced urban landscapes. Interim usages and valued ecologies slowed down effects of urbanisation and gave “voice” to particular characteristics of urban nature through which the Paljassaare Peninsula and migratory corridors of birds became part of a wider urban change. The desired (urban) nature appears as an expression of good and bad ecologies influenced by imaginations about landscapes and infrastructure. The evolvement of green areas and waterfront spaces in post-socialist cities is approached as part of Europeanisation, in which practices of European Union states are smoothly and uncritically adapted. The example of Paljassaare reveals entangled multi-dimensional connections between history, civil-society initiatives, and ideas of spatial planning, which were based on care and enabled the bordering of Natura 2000 bird protection area despite urbanisation pressure. Therefore, urban nature and urban landscapes as contested links between the (post)Soviet heritage and Europeanisation require in-depth analysis for revealing a more complex process than linear transformation. The following of disturbance-based ecologies and longer durations make it possible to problematise the Soviet-era homogenous legacy. Anthropocene traces, as a dominant force of humankind, have materialised in Paljassaare through industry, mining, building of a military complex and infrastructure of urbanisation, which, step-by-step, firmly linked the former islands to the city. Urban spatial futures lean on environmental legacy and simultaneously try to distance from the dark side of legacies. The paradox is that the terrains extensively disturbed by human activities can become meaningful within landscapes in problematising the forces of humankind and the position of humans in the context of the Anthropocene.

Outward expansion or networked growth? Comparing farmland loss in evolving urban agglomerations across Mollisol regions in the northern hemisphere

Many cities in Mollisol (black earth) regions need to revitalize their local economies while avoiding excessive farmland consumption, which could have a global impact. To resolve this dilemma, we have to understand how urbanization interacts with farmland loss, which requires factoring in their interconnected influences. The Chicago urban agglomeration (CUA), Harbin−Changchun urban agglomeration (HCUA) and Dnipro−Kamianske urban agglomeration (DKUA) were selected to compare farmland loss in relation to urban morphology, growth patterns and networked cities during 2000–2020. Our results show that trends in farmland loss can be differentiated between individual cities, and also controlled via their interconnections. Overall, expansion of CUA and DKUA has decelerated but HCUA is still undergoing rapid urbanization, with its area increasing by 116 %. Urbanization pressure has shifted from core cities to small and medium-sized cities, which have also experienced directional farmland loss, towards their influential neighbors. Farmland loss disparities between different intra- and inter-UA subgroups are prominent, demonstrating that occupation pressure is diverse and phased in a UA, and cannot be addressed by a one-size-fits-all form of zoning control. These findings support the conservation and protection of fertile soils from urbanization pressure, and promote international cooperation between global Mollisol regions.

Effective degradation of organophosphate ester flame retardants and plasticizers in coastal sediments under high urban pressure

Empirical evidence of the effective degradation at environmentally relevant conditions of organophosphate esters (OPEs) flame retardants and plasticizers in coastal sediments from an impacted area in the NW Mediterranean Sea is provided. Half-lives varied from 23.3 to 77.0 (abiotic conditions) and from 16.8 to 46.8 days (biotic conditions), depending on the compound, highlighting the relevant role of microbial assemblages enhancing OPE degradation. After an immediate significant reduction of the bacterial abundance due to OPE addition to the sediment at the very beginning of the experiment, the observed biodegradation was associated to a general stimulation of the growth of the bacterial community during a first period, but without a marked change of the structure of the community. However, OPE contamination induced a decrease on the diversity of the bacterial community in the coastal sediment, noticeable after 14 days of incubation. It is likely that on one side the contamination had favoured the growth of some bacterial groups maybe involved in the biodegradation of these compounds but, on the other side, had also impacted some sensitive bacteria. The estimated half-lives fill a data gap concerning OPE degradation rates in marine sediments and will be valuable data for the refinement of OPE chemical risk assessment in marine environments, particularly on impacted sites.

Peri-urban agrifood systems and a landscape project in the southern Mediterranean. The case of the urban agglomeration of Sousse (Tunisia)

Peri-urban agrifood systems are often subject to urban pressure and other territorial factors, which justifies a detailed study and analysis from multiple points of view. The main objective of this work is to analyze the periurban agri-food systems of the urban agglomeration of Sousse (Tunisia), one of the most important in the country, from a landscape perspective. This work adds to the literature on policies and strategies for the planning and development of Tunisian cities, which are currently facing several environmental and social challenges, of which climate change, food security and sustainable development are the most important. This research focuses, as mentioned above, on the case of the urban agglomeration of Sousse (Tunisia), where the concurrence of different factors (political, environmental, economic, etc.), together with clearly deficient regulations and uncontrolled urban development, is threatening the survival of a traditional, largely family-based agricultural model, based on a mixed or polyculture production system, with olive groves predominating. The latter is vital to ensure the economic maintenance of many families and to actively contribute to food security, with the consequent production of varied, fresh, and quality food. In this sense, we present a specific method that, based on the integrative and strategic significance of landscapes, and on the Landscape Character Assessment methodology, employs the so-called “landscape project” as a tool to strengthen the resilience and sustainability of peri-urban agriculture and to prevent the loss of a landscape heritage that has always been considered crucial for the identity of the local population. The document highlights the importance of the concept of green infrastructure, which, when properly integrated into land-use planning instruments, can contribute to enhancing local and sustainable agri-food systems. It also points out the need to promote Agricultural Parks, a protected status already recognized in Spain and other countries, as instruments for management, promotion, and development, and puts forward some specific proposals for the enhancement and activation of peri-urban agricultural landscapes in the Sousse conurbation. In relation to this last aspect, it insists on the need to modify the current forms of governance, which would require greater leadership and involvement of the main actors in peri-urban agriculture.

The effects of urbanisation pressures on smallholder staple food crop production at the fringes of African cities: Empirical evidence from Ghana

The effects of urbanisation pressures on smallholder staple food crop production at the fringes of African cities: Empirical evidence from Ghana

Multipurpose plants in home gardens of Guarulhos (São Paulo State, Brazil): from biodiversity conservation to public health

Introduction: Among the human adaptive strategies, plant cultivation is one of the most important over the last ten thousand years. However, with the development of large urban centers, human population resign some habits in relation of plant cultivation. Recently home gardens have received attention as an important germplasm bank, preserving many non-commercial species. Objective: This study aims to investigate the diversity of plants cultivated in home gardens. Was also explored how the human population relation with these resources. Originality: Home gardens have a high potential to maintain resources for urban biodiversity through the variety of plants that are cultivated. However, predominantly small cities are targets of studies of this nature, and large cities are the ones that suffer the most from urbanization pressure. Thus, this work brings this approach to the second largest city in the metropolitan region of São Paulo. Methodology: The population of President Dutra and Bonsucesso in the city of Guarulhos, SP, was studied. We interview 150 people, being 102 at the Presidente Dutra district and 48 in Bonsucesso neighborhood. It was used a semi-structured and random selection of households surveyed. Results: The neighborhoods prevailed the cultivation of ornamental plants which were represented by 51 botanical families, followed by food related plants with 38 botanical families and medicinal plants with 15 botanical families. Contributions: These data indicate a preference for the cultivation of ornamental plants in backyards in the city of Guarulhos, SP. Conclusions: Residential backyards of the city of Guarulhos showed numerous purposes such as leisure space, housework, car garage and shelter for animals; however, there is a strong occurrence of cultivated plants.

Religious Tastes in a Gentrified Neighbourhood

Abstract This article examines how religious diversity is manifested and represented in contexts undergoing intense urban pressures. Drawing on ethnographic research conducted in the Raval quarter of Barcelona, we analyse the open-air festivities of religious minorities and the emergence of new neighbourhood associations’ mobilizations. Specifically, we focus on the role of food in these events as a way to explore how diversification and urban transformation interrelate. Whilst food becomes the means through which religious and secular actors interact and articulate forms of place-making, it also becomes a resource to present religion in forms deemed ‘acceptable’ to the general public.

Characterisation and Treatment of Automobile and Battery Water Waste Using Coagulation and Adsorption Technique

Adsorption processes have seen a broad level of usage by various researchers over the years to remove heavy metals from waste streams. An adsorbent frequently used is activated carbon. Although activated carbon is used extensively in water and wastewater industries, it remains expensive. In recent years, there has been a need for economical and safe methods for heavy metal elimination from contaminated water. This need has only grown, which gave rise to research aimed toward producing low-cost alternatives to activated carbon. There is an urgent need to explore all possible sources of inexpensive agro-based adsorbents, and heavy metal removal's feasibility should be studied in great detail. This research objective is to learn how inexpensive adsorbents can remove heavy metals from wastewater. Treating Automobile battery waste efficiently remains a significant challenge due to its enormous quantity, hazardous nature, and complexity. When effective treatment technology has poor implementation, this aggravates the situation and worsens the situation further in countries with high and rising populations. This leads to more pressures of urbanisation and industrials, giving room for more industrial waste. This research suggests the best possible options by critically reviewing the existing practices. While slow biological treatment schemes usually fail to support microbial activities in the presence of toxic components in concentrations, other physicochemical plans often need to meet strict waste disposal and discharge regulations. The approach where sludge disposal is thermally incinerated has never seen environmental justification, and this is because of dioxin release and obnoxious substances transferred directly. Newly emerging membrane-based schemes can be flexible, environmentally friendly, petite, economically self-sufficient, and easy to implement and maintain after installation.

Spatial patterns of reef fishes and corals in the thermally extreme waters of Qatar

The Persian Gulf is a thermally extreme environment in which reef corals have adapted to survive through temperature ranges that would be lethal to corals from other regions. Despite offering a unique opportunity to better understand how corals from other regions may adapt in the future, through a changing climate, much of the Gulf coral and fish communities remain to be described. In the southwestern Gulf nation of Qatar few reef sites have been described to date. We here characterize reef communities from 16 sites around the Qatar Peninsula, encompassing depths from 3 to 25m. We found the healthiest coral reef communities to be in deeper offshore reefs, with high coral and fish species richness and high coral abundance, likely a result of their occurrence below summer thermocline depths and distance from urban pressures. In contrast, we found shallow reefs, both nearshore and offshore, to have low species richness and abundance relative to deeper reefs, presumably due to impacts from recurrent bleaching events and development pressures over recent decades. The results of this work underscore the Qatar Peninsula as being at the biogeographic epicenter of the wider Gulf. However, further temperature increases may push both fishes and corals over their physiological limits. Management efforts at both the regional and global level are needed to reduce thermal stressors and preserve the rich reef ecosystems found in the waters surrounding Qatar.

Protected area geographical management model from design to implementation for specially protected environment area

Turkish National GIS (TNGIS) studies have been accelerated to standardize Turkish land administration after INSPIRE and LADM and to be a part of the e-Turkey transformation process. In the process, one of the geographical data sets transferred from the classical environment to e-government platforms is the protected areas. This study was carried out for a Specially Protected Environment Area (SPEA). The Göksu Delta has been determined as the study area. In the study, an interview form was used as a data collection tool. Then, the geographical data model design of the SPEA was carried out with UML schemes. The most important results obtained from the study are the necessity of preparing UML diagrams for all protected areas together with field experts and integrating them into TNGIS, and the necessity of using such protected areas under urban pressure in a more controlled manner in a dynamic structure with the GIS system.

Construction and Quality Control of Subway Wet Loess in Concealed Tunnel Based on Particle Swarm Optimization Algorithm

To reduce urban pressure, urban rail transit has become an effective way to reduce traffic congestion, mitigate traffic accidents, reduce environmental pollution, and improve commuting efficiency. Subway as the main means of urban public transport travel, in recent years by people’s favor, although the construction industry of rail transit is developing rapidly and the industry scale is expanding, but because the construction of rail transit construction projects is very difficult, especially in the wet loess within the concealed excavation tunnel, but also frequent accidents, and the quality of the project is not easy to guarantee, so the underground railroad wet loess within the concealed excavation tunnel construction technology is poor. Therefore, it is especially important to study the construction technology and project quality management of underground railway concealed tunnel in wet loess. In this paper, based on the in-depth study of the basic principle of quantum particle swarm optimization calculation and the realization of key engineering technologies, the particle swarm optimization algorithm is programed using MATLAB software, and the coding scheme, operation specification, and operation parameters are designed. Then, combined with the particle swarm optimization algorithm and assisted MATLAB software, the main analysis of the construction and quality control of wet loess in concealed tunnels of subway projects was carried out, mainly by systematizing the relationship between the three major elements of subway project schedule, cost, and management and the construction and quality control of wet loess in concealed tunnels of a subway, and concluded that the construction and quality control of wet loess in concealed tunnels of the subway needed schedule. It is concluded that the construction and quality control of subway wet loess tunnel requires stable schedule, adequate cost budget, and management personnel.

Ecological Response of Urban Forest Carbon Density to Site Conditions: A Case Study of a Typical Karst Mountainous Regions in Southwest China

Understanding the ecological constraints of limiting the magnitude and the allocation of carbon density is critical for executing adaptive forest management programs and upgrading the size of carbon sinks. Taking a typical karst mountainous region Guiyang City as a case study area, this study computed the biomass of different forest types using the volume–biomass equations and mapped the carbon density distribution of forests. Furthermore, the random forest algorithm and spatial autoregression model were adopted to reveal the effects of site conditions on carbon density in karst forests. The results indicate that the forest ecosystems of Guiyang City had a high carbon sequestration potential, and there was a significant difference in the carbon density of forests in terms of space dimensions. Road density, 0 cm cation exchange capacity, and soil parent materials were the dominant factors determining the spatial distribution of homogeneous units with different levels of carbon density. This study underlines the urgency adapting to the growing conditions of forests in terms of complex site conditions, and provides a scientific basis for optimizing forest management practices, to maintain their carbon sequestration capacity under urbanization pressure and fragile habitats.

The dark side of the Common Agricultural Policy

The dark side of the Common Agricultural Policy

Predicting housing deprivation from space in the slums of Dhaka

Cities in developing countries have been struggling to deal with the pressures of urbanization on infrastructure, basic services, land, and housing that often manifest as poor living conditions found in slums and informal settlements. One of the key challenges to effectively target policy interventions and meet Sustainable Development Goals (SDGs) for improving lives of people living in slums is the lack of data on their housing condition. Furthermore, the slum/non-slum dichotomy is inadequate in identifying specific deprivations that prevents effective policymaking and implementation. To this end, we propose a methodological framework to predict multidimensional housing deprivation with slums of Dhaka, Bangladesh as our case study. Our framework predicts multidimensional housing deprivation using geospatial and remote sensing variables. Several indicators, including distance to the central business district, arterial roads, major road junctions, railroads, average dwelling size, and street type within slums were related to increased risk of overall deprivation whereas proximity to heavy industry and shoreline, building density, informal street pattern, the low-level connectivity and proximity to social amenities were related to lower risk of housing deprivation. The results from the statistical models indicate their potential to predict the extent and type of housing deprivation, which could in turn support planning and policy interventions for achieving SDGs for the most vulnerable populations in slums of developing countries.

Distribution patterns of lake-wetland cultural ecosystem services in highland

Environmental and ecological degradation are more prominent within lake-wetland ecosystem than any other ecosystem on Earth, especially in the highlands. The continued pressures of population growth and rapid urbanization on cultural ecosystem services (CES) provided by lake-wetland ecosystem in highlands present ongoing challenges to decision-makers and managers. In this paper, Social Values for Ecosystem Services model (SolVES) was used to map, quantify and assess CES in Dianchi lake basin (DLB) and Erhai lake basin (ELB) to understand the spatial dynamics of CES perceived by residents and tourists. After combining the field survey data with four environmental variables, our analysis shows that (1) The Maximum Value Index (M-VI) ranking of the three CES in descending order within DLB was aesthetic (M-VI = 10), recreation (M-VI = 10), cultural (M-VI = 8). (2) Different stakeholders (residents and tourists) had different perceptions of CES. Recreation value between residents and tourists had the same M-VI (M-VI = 10), but the M-VI of aesthetic value (M-VI = 10) perceived by tourists was higher than those perceived by residents. (3) The four environmental variables significantly influenced CES, especially distance to water and dominant landcover. (4) CES were transferable from DLB to ELB due to the potential transferability of Maxent's DLB models for each CES, and CES hotspots in ELB generated from SolVES were highly consistent with high kernel-density areas. In conclusion, SolVES incorporating CES can benefit the basin resource managers when seeking to integrate a social perspective into the resource management decision-making process. In particular, the involvement of various stakeholders ensures that they are not marginalized in environmental planning and management.

Multiscale spatiotemporal dynamics analysis of urban green space: Implications for green space planning in the rapid urbanizing Hefei City, China

Under the pressure of rapid urbanization, the spatiotemporal dynamics of urban green spaces (UGS) have enormous impacts on the local ecological system and environment at different scales. In this study, UGS in Hefei City, which has experienced rapid urbanization from 1995 to 2015, were extracted based on time-series Landsat-5 TM and Landsat-8 OLI images, and different types of parks were mapped based on GF-2 images combined with multi-source metadata. Dynamic patterns of green space were examined by drawing the spatial variations of green space at the city, inner city, and park scales. Results revealed that: (1) At the city level, UGS decreased with the rapid urbanization, especially farmland sharply lost in areas around existing urban areas and along the transportation corridors. (2) At the inner-city level, concentric analyses showed that UGS changes in different rings had unique trends, and the dynamic changes were the most significant in Rings 2 and 3. Comparative analysis of old and new districts showed that the common characteristics of UGS changes were the transfer-out of farmland and the transfer-in of built-up land, and the newer the region, the more intense the changes. (3) At the park level, the number and area of urban parks were increasing from the center to the periphery, and the type of park gradually changed from single to rich. Significant spatial heterogeneity was identified in the landscape patterns of urban parks based on fishnet cell analysis. It is fundamental to assign urban construction land for socio-economic development, while planning UGS at different scales; moreover, integrating different green space-related policies could protect the UGS and maintain its stability. Only in this way can UGS combine economic, social, and ecological benefits under the background of rapid urbanization.

Potential energetic return on investment positively correlated with overall soil microbial activity

Microbial communities are a critical component of the soil carbon (C) cycle as they are responsible for the decomposition of both organic inputs from plants and of soil organic C. However, there is still no consensus about how to explicitly represent their role in terrestrial C cycling. The objective of the study was to determine how the molecular and energetic properties of readily available organic matter affect the metabolic activity of the resident microbial communities in soils. This was achieved by cross-amending six soils, taken from woodland and grassland sites along an urban pressure gradient, with organic matter extracted from the same six soils and measuring heat dissipated due to the increase in microbial metabolic activity. The energetic properties of the organic matter were used to estimate a potential energetic return on investment (ROI) that microbial communities could obtain from the transformation of the organic matter. Specifically, the ROI was calculated as the ratio between the total net energy available (ΔE) and the weighted average standard state Gibbs energies of oxidation half reactions of organic C (ΔG°Cox). ΔE was measured as the heat of combustion using bomb calorimetry. ΔG°Cox was estimated using the average nominal oxidation state of C (NOSC) of the molecular species in the organic matter. The overall metabolic activity of microbial communities was positively related to the potential energetic return on investment but no significant relationship was found with the molecular diversity of organic matter. The temporal differences in metabolism across soils indicate that bacterial communities do not exploit the potential energetic return on investment in the same way: the suburban grassland communities responded more rapidly and the suburban woodland communities more slowly to the organic matter additions than the other communities. The urban gradient did not affect the properties of the molecular or energetic properties of the organic matter nor the response of the microbial communities to the organic matter additions. However, the organic matter from the grassland soils caused soils to dissipate 36.4% more heat than organic matter from the woodland soils. The metabolic response was also more rapid after the addition of grassland organic matter: the time taken for half the heat to be dissipated was 6.4 h after the addition of grassland organic matter and 6.1 h after the addition of woodland organic matter. Overall, our results suggest that microbial communities preferentially use organic matter with a high potential energetic return on investment, i.e. organic molecules that do not require high cost associated with catalysis whilst yielding a high net energetic benefit.