Form Of Land Use Change Research Articles

Thriving arid oasis urban agglomerations: Optimizing ecosystem services pattern under future climate change scenarios using dynamic Bayesian network

The effects of global climate change and human activities are anticipated to significantly impact ecosystem services (ESs), particularly in urban agglomerations of arid regions. This paper proposes a framework integrating the dynamic Bayesian network (DBN), system dynamics (SD) model, patch generation land use simulation (PLUS) model, and the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model for predicting land use change and optimizing ESs spatial patterns that is built upon the SSP-RCP scenarios from CMIP6. This framework is applied to the oasis urban agglomeration on the northern slope of the Tianshan Mountains in Xinjiang (UANSTM), China. The findings indicate that both the SD model and PLUS model can accurately forecast the distribution of future land use. The SD model shows a relative error of less than 2.32%, while the PLUS model demonstrates a Kappa coefficient of 0.89. The land use pattern displays obvious spatial heterogeneity under different climate scenarios. The expansion of cultivated land and construction land is the main form of land use change in UANSTM in the future. The DBN model proficiently simulates the interactive relationships between ESs and diverse factors. The classification error rates for net primary productivity (NPP), habitat quality (HQ), water yield (WY), and soil retention (SR) are 20.04%, 3.47%, 4.45%, and 13.42%, respectively. The prediction and diagnosis of DBN determine the optimal ESs development scenario and the optimal ESs region in the study area. It is found that the majority of ESs in UANSTM are predominantly influenced by natural factors with the exception of HQ. The socio-economic development plays a minor role in such urban agglomerations. This study offers significant insights that can contribute to the fields of ecological protection and land use planning in arid urban agglomerations worldwide.

Native forests transformed into cash crops reduced soil multi-functionality by modifying the microbial community composition and keystone species' abundance in the Jianghuai Hilly Region.

Conversion of native forest to cash crops is the predominant form of land use change in the Jianghuai Hilly Region. However, how plantations with different cash crops affect the soil multi-functionality is not well documented. In this study, we collected three kinds of cash crops soils (vegetable, orchard, and tea) and forest soil, to systematically review the relationship between soil microbial communities and soil multi-functionality. Soil multi-functionality had decreased in vegetable and orchard as compared to native forest, whereas tea plantation had no significant effects on soil multi-functionality. The results also showed that cash crop plantations decreased soil multi-functionality by shifting keystone species' abundance, for forest, vegetable, and orchard, the keystone species that were classified as module hubs in the bacterial co-occurrence network significantly negatively contributed to soil multi-functionality, but the keystone species categorized as module hubs in fungal co-occurrence network positively affected soil multi-functionality. Multiple soil properties were the drivers of the soil microbial community; thus, indicating that the altered soil properties under cash crop plantations were vital in determining microbial composition and biological processes. These results identified that sustainable management strategy in cash crop plantation needed to be developed for improving soil multi-functionality.

Diversity and abundance of bees (Hymenoptera: Apidae) in the campus 4 of Ahmad Dahlan University

Land conversion around campus 4 of Ahmad Dahlan University Yogyakarta affects the diversity and abundance of pollinating insects, one of which is bees. The purpose of this study was to calculate the level of diversity and abundance of bees on campus 4 UAD and its surroundings. The sampling area consisted of 4 plots, with each plot measuring 1750 m2( 35 m x 50 m) determined using the observation method. Sampling was carried out three times, which was carried out in the morning at 07.00 – 11.00 and continued in the afternoon at 15.00 – 17.00. Bees were identified by comparing their morphological characters with identification reference books and journals. The Spearman correlation test then analyzed the bee abundance data and abiotic factors. The results showed that the level of bee diversity on campus 4 UAD and its surroundings was moderate (1 H' 3). The most abundant bee species was Xylocopa aestuan, with 118 individuals, and the least abundant was Apis mellifera, with 7 individuals. The conclusion of this study is the state of the ecosystem on campus 4 UAD and its surroundings, there is a disturbance in the form of land use change, but bees can still tolerate the disturbance.

Soil quality cannot be improved after thirty years of land use change from forest to rangeland

Soil quality can be assessed by measuring its physical, chemical and biological properties. In terrestrial ecosystems, the knowledge of the status of soil quality under different land use/cover can increase our understanding of processes related to soil functioning and help to properly managing ecosystems and increase their services. Conversion of the forest to rangelands is one of the most common forms of land use change having a significant effect on soil quality indicators. Here, we addressed the following objectives: (ii) to study the current status of soil physical, chemical and biological characteristics after more than thirty years of land use change from forest (dominated by Carpinus betulus and Parrotia persica) to rangeland, and (ii) to provide an overview of the spatial distributions of soil properties in forest and rangeland covers using a geostatistical method. For this, two sites (i.e., forest and rangeland) were selected in northern Iran. Within each site, 50 soil samples were collected at 0–10 cm depth along two sampling lines (250 m length) with a total of 100 soil samples for each site. Results showed that following the change of land use from forest to rangeland soil porosity, aggregate stability, pH, electrical conductivity and nutrient (i.e., total N and available P, K, Ca and Mg) contents increased, whereas soil bulk density and C/N ratio decreased. In addition, the population of soil biota (i.e., earthworms, acarina, collembola, nematode, protozoa, bacteria and fungi), microbial and enzyme activities decreased after more than thirty years of land use change from forest to rangeland. Principal component analysis confirmed that forest site had a more fertile soil and a higher biological activity than rangeland cover. Based on heat plots of soil properties, forest ecosystems created hot spots of soil quality indicators in the study area. Based on the geostatistical approach, most of the soil variables in the rangeland site followed a linear model, while in the forest site, most models were exponential and spherical. The fractal dimension values of the soil properties in the forest (1.62–1.99) had larger variations than in the rangeland (1.75–1.99) site. As a general conclusion, soil quality was not improved after more than thirty years of land use change from forest to rangeland, suggesting that degraded forest habitats should be restored by native tree species rather than converted to other land uses.

Valuasi Ekonomi Konversi Lahan Pertanian Di Kawasan Aerotropolis Kulon Progo

The construction of the Yogyakarta International Airport (YIA) in Temon District, Kulon Progo Regency has various impacts, one of which is the growth of the aerotropolis area which causes changes in land use. The conversion of land use, causing any difference in economic valuation. The purpose of this research is to determine the impact of agricultural land conversion through economic value of the Kulon Progo aerotropolis area, with case studies in Palihan, Sindutan, Jangkaran, Kebonrejo and Glagah village. This research uses a non-empirical study method while research approach uses a mixed quantitative and qualitative approach. The analysis used in the form of land use change by digitizing the image (CSTR) of land and geo-referencing overlay in ArcGis, as well as economic valuation analysis. The result shows that changes in economic value have decreased for the use of agricultural and pond fields, while for settlements, the economic value after the construction of YIA has increased.

Land Use Dynamics and Mobility Patterns in Muscat Capital Area:Insights from a Detailed Study of Al-Ghubra North

Muscat, the capital of the Sultanate of Oman, has been developed since the 1970s with typical characteristics such as high urbanization rate, low-density urban sprawl, and private car based mobility. Land-use patterns favour the separation of functions, creating long distances for daily trips and a high traffic volume. State investments went into developing and improving the road network while the public transport has been neglected for a long time. In light of depleting resources and the recent decline of oil revenues, however, a first rethinking of transport policies and land use planning has set in. Diversifying the economy has become a major aim and efforts are made to encourage the private sector and to attract foreign direct investment. With regard to urban development, these policies are reflected in increasing changes in land use patterns. The paper analyses ongoing land use changes in al-Ghubra North, a multifunctional neighbourhood in Muscat, and discusses how far these forms of land use change contribute to a more sustainable urban structure and more sustainable mobility patterns.

Potential rents vs. potential lives

The seeking of potential rents directs flows of investment into built and natural environments, suffusing volatility into urban and rural landscapes, generating gentrification and other forms of land use change, and displacing lives and livelihoods to make space for ‘improvement’, ‘highest and best use’, ‘revitalization’, or the like. In this paper we argue that potential rents are captured at the cost of potential lives, and that rent gap theory, long central (and limited) to gentrification theory, is more widely applicable to the dynamics of land use change and uneven geographical development in capitalist societies. By reading David Harvey’s analyses of rent and accumulation by dispossession as a sophisticated formulation of rent gap theory, we relate the seeking and capturing of potential rents to the power of landed developer interests and a broadened conceptualization of rentiership. We furthermore relate the seeking of potential rents to an ideology of limitless accumulation, and the striving to rein in potential rents to ideas of degrowth and the need for a culture and a politics of limits. Brief vignettes from the ‘primary sector’ (fisheries in the Baltic Sea, dairy farming in Europe, and small-scale farming in Sweden) suggestively illustrate our central argument that the seeking and capturing of potential rents stand in stark opposition to potentials for wellbeing and flourishing of human and non-human lives. We conclude that constraining potential rents – founded as they are on faith in limitless growth – requires a culture of self-limitation and politically imposed limitations commensurable with post-capitalist societies.

Comprehensive Assessment of the Effect of Urban Built-Up Land Expansion and Climate Change on Net Primary Productivity

Urbanization is causing profound changes in ecosystem functions at local and regional scales. The net primary productivity (NPP) is an important indicator of global change, rapid urbanization and climate change will have a significant impact on NPP, and urban expansion and climate change in different regions have different impacts on NPP, especially in densely populated areas. However, to date, efforts to quantify urban expansion and climate change have been limited, and the impact of long-term continuous changes in NPP has not been well understood. Based on land use data, night light data, NPP data, climate data, and a series of social and economic data, we performed a comprehensive analysis of land use change in terms of type and intensity and explored the pattern of urban expansion and its relationship with NPP and climate change for the period of 2000–2015, taking Zhengzhou, China, as an example. The results show that the major form of land use change was cropland to built-up land during the 2000–2015 period, with a total area of 367.51 km2 converted. The NPP exhibited a generally increasing trend in the study area except for built-up land and water area. The average correlation coefficients between temperature and NPP and precipitation and NPP were 0.267 and 0.020, respectively, indicating that an increase in temperature and precipitation can promote NPP despite significant spatial differences. During the examined period, most expansion areas exhibited an increasing NPP trend, indicating that the influence of urban expansion on NPP is mainly characterized by an evident influence of the expansion area. The study can provide a reference for Zhengzhou and even the world's practical research to improve land use efficiency, increase agricultural productivity and natural carbon sinks, and maintain low-carbon development.

Pollinator Communities of Restored Sandhills: a Comparison of Insect Visitation Rates to Generalist and Specialist Flowering Plants in Sandhill Ecosystems of Central Florida

Globally, urbanization and other forms of land use change have been implicated in widespread pollinator declines and disruptions to plant–pollinator interactions. A growing body of literature, however, suggests that urban habitat fragments can provide oases for both plant and insect diversity. A micro-ecosystem on our college campus was created to represent the longleaf pine savannas (sandhills) that once dominated upland ridges throughout the Southeast. To assess the ability of this site to support wild insect pollinators, from May through August for three years (2016–2018) we compared visitation to two abundant flowering plant species, Bidens alba (a generalist-pollinated composite) and Chamaecrista fasciculata (a specialist-pollinated legume), between the campus micro-ecosystem and a nearby site within a large conservation area containing sandhill habitat undergoing restoration. We found that, for both plant species, total insect visitation rates did not differ between years or sites, suggesting that the small urban fragment is capable of maintaining abundant pollinators. The identity of generalist visitors to Bidens alba, however, differed dramatically between sites. Wild hymenopterans constituted more than two-thirds of all insect visits in the campus site but less than half in the conservation area, where butterflies, flies, and beetles were also common visitors. The high density of flowers in the campus site is likely at least partially responsible for the high abundance of hymenopterans, a result consistent with that of many other studies showing that hymenopterans are less sensitive to urbanization than are other insect groups.

Excess Nitrate Export in Mountaintop Removal Coal Mining Watersheds

AbstractThroughout the Central Appalachian ecoregion, mountaintop removal coal mining (MTM) is the predominant form of land use change. The streams draining MTM impacted watersheds have been reported to contain high stream nitrate (NO3−) concentrations, yet the source and persistence of elevated NO3− remains unknown. Here we compiled data from multiple sources to conduct a regional evaluation of the impact of mining on stream NO3−, examine NO3− persistence after mining cessation, and identify potential N sources. Using water quality data from six large watersheds, we observe elevated NO3− in watersheds with the highest active mining density. At four small MTM watersheds with repeat sampling, we found that high levels of NO3− concentrations declined after mining cessation but remain elevated above reference after several decades. At MTM watersheds, we found annual mass flux of NO3− was 3.68 to 26.4 kg N ha−1 year−1, which is 1 to 2 orders of magnitude higher than a nearby forested reference watershed. Stream water NO3− isotopic ratios at these sites did not match previously suggested NO3− sources such as explosives used during mining and fertilizer applied during reclamation but were highly enriched in both δ15N and δ18O compared to the reference watershed suggesting high rates of NO3− retention. Explosive residue could account for the bulk of watershed NO3− export during active mining phases but other mining related N sources including fertilizer and rock‐derived N, the construction of valley fills, and alterations in watershed NO3‐ cycling likely contribute to the persistence of elevated NO3− export observed in this study.

Amazon deforestation drives malaria transmission, and malaria burden reduces forest clearing: a retrospective study

BackgroundDeforestation and other forms of land use change are among the most pressing anthropogenic environmental impacts. In Brazil, a recent resurgence of malaria paralleled rapid deforestation and settlement in the Amazon basin, yet empirical evidence of a deforestation-driven increase in malaria remains surprisingly equivocal. We hypothesise that an underlying cause of this ambiguity is that deforestation and malaria influence each other in bidirectional causal relationships, where deforestation increases malaria through ecological mechanisms and malaria simultaneously reduces deforestation through socioeconomic mechanisms. MethodsWe tested our hypotheses with a large and robust geospatial dataset encompassing 807 municipalities across 13 years and show that deforestation has a strong positive effect on human malaria incidence, controlling for variation over space and time and across gradients of land use intensification. FindingsOur results suggest that a 10% increase in deforestation leads to a 3·7% increase in Plasmodium falciparum malaria cases (about 1730 additional cases in 2008). The effect is larger in the interior and absent on the fringe of the Amazon where little forest remains. However, this strong effect is only detectable after controlling for a feedback of malaria burden on forest loss, whereby increased malaria burden significantly reduces forest clearing, possibly mediated by human behaviour or economic development. We estimated that for a 1% increase in P falciparum malaria, we would expect a 1·5% decrease in forest area cleared (about 235 fewer km2 lost in 2008). InterpretationThis bidirectional socioecological feedback between deforestation and malaria, which attenuates as land use intensifies, shows the intimate ties between environmental change and human health. FundingUS National Science Foundation Postdoctoral Research Fellowship in Biology (#1611767).

Analyzing Land Use and Change Detection in Eastern Nigeria Using GIS and Remote Sensing

The pace and pattern of various forms of land use change and degradation continues at alarming proportion in several areas in Sub-Saharan Africa. Given the emergent risks, recurrent subsidence and erosions rank as permanent features in some areas of the continent like Nigeria. This exacerbates natural constraints on agricultural production and poor soil quality with damage to natural areas. The severity of gullies in all that, drive the destruction of vast areas in Eastern Nigeria due to intense farming and other elements. All these types of degradation cause declines in the productive capacity of land through reduced yields. For policy makers, the problem is difficult to determine precisely due to limited access to geo-spatial assessment as a decision support tool. Accordingly, there is an urgent need for regular use of such devices in assessing the severity of land degradation and change. To fill that void, this study analyzes land degradation issues in Eastern Nigeria with the latest advances in GIS and remote sensing technologies. Emphasis is on the issues, impacts, factors, efforts and remedies. In terms of methodology, the paper adopts a mix scale approach involving descriptive statistics coupled with geo-spatial technologies of GIS and remote sensing. The results from the use of these techniques point to widespread changes involving gains, declines and degradation in the region’s landscape over the years. While the size of land types devoted to agriculture, bare soil, forest and urban land surged in the study area, bushland, grassland and areas covered by water declined from 2000 to 2017. The region also experienced greater threats from the exposure to recurrent land degradation as manifested with the occurrence of erosion hazards across various sites. The emergent spatial patterns not only revealed concentration of agricultural land class along the upland northern axis of the region along Ebonyi and Enugu and clusters of forest cover on the lower south part (Imo and Abia). GIS mappings showed the dispersion of erosion hazards in some of the states. With change attributed to a host of factors raging from competing land use made up of mining, agriculture, ineffective policy, poor conservation and environmental and physical elements. The paper suggested the need for education, effective policy, local participation, soil conservation and the design of regional land use information system as remedies.

Linking carbon and water cycles with forests

ABSTRACTThis article discusses carbon and water cycles in relation to forested ecosystems, specifically the role forests play in storing and releasing carbon, and the role they can play in local to regional water cycles (including river flooding and evapotranspiration). It also looks at disturbances in the form of land use change, deforestation, and climate change. The article highlights how linking carbon and water cycles with forests demonstrates the interdisciplinary nature of these biogeochemical cycles in one of the most crucial of Earth's systems. The article closes with a discussion of how effective understanding of these topics will hinge on educators and students making synoptic links between these cycles, and how this can trigger outdoor learning through collection and analysis of data.

Spatial-temporal evolution and classification of marginalization of cultivated land in the process of urbanization

Marginalization of cultivated land, resulting from rapid urbanization, exists as an important form of land use change, and represents a new research direction in land-use and land-cover change (LUCC). This article proposes a classification of such marginalization on the basis of elasticity of input and income, categorizing marginalization of cultivated land as either policy-induced (PIM), nature-induced (NIM) or economy-induced (EIM) marginalization. These classifications are further explored as either positive or negative marginalization, depending on whether the land is transformed from or into cultivated land. This innovative framework is applied to analyses of marginalization in Lianjiang County, located in southeastern coastal China. This research analyzes characteristics of spatial-temporal evolution of categories of marginalization of cultivated land using 3D kernel density methods. Significant findings point to spatial-temporal processes and driving forces of marginalization, including: (1) Concentrations of positive (P-PIM) and negative (N-PIM) policy-induced marginalization both occur and agglomerate in separate spaces, with the former mainly in the southeastern portion of the county and the latter in the northwest. (2) By contrast, patterns of positive (P-NIM) and negative (N-NIM) nature-induced marginalization complement each other in space - N-NIM tends to be more discrete in areas with P-NIM aggregations, and vice versa. (3) Finally, areas with aggregations of positive (P-EIM) and negative (N-EIM) economy-induced marginalization overlap. The research suggests that relevant land use policies should be formulated in response to these characteristics of cultivated land marginalization so as to address marginalization of cultivated land, especially as associated with rapid urbanization.

A Global Synthesis of Jatropha Cultivation: Insights into Land Use Change and Management Practices.

Despite setbacks, interest in Jatropha cultivation remains high. This study addressed the question to what extent Jatropha cultivation has replaced specific vegetation and land use types and how the existing areas are managed. Major forms of land use change and management practices were identified based on cluster analysis of data from 106 interviewee's responses to a comprehensive global survey. Of the 1.04 × 10(6) ha cultivated with Jatropha in 2011 40% were established on land that was cleared of vegetation as a result of logging activities unrelated to Jatropha cultivation, 34% was defined as unused, and the remainder was attributable to areas previously used for crops or animal husbandry. With the exception of croplands, these areas were dominated (90-98%) by a few internationally active companies whose cultivation models were almost exclusively based on outgrower schemes. Management practices were largely extensive in nature (low mechanical input and infrequent use of fertilizers, pesticides and herbicides), and also dominated by large projects. Broad surveys, such as this, are useful in identifying general trends in this emerging global industry, but detailed case studies, particularly of large projects, are needed in order to draw more informed conclusions about the site-specific impacts of Jatropha cultivation.

Increasing nitrate concentrations in streams draining into Lake Ontario

Abstract Nitrate (NO 3 -N) concentrations in offshore waters of Lake Ontario increased by approximately 60% between the 1970s and 2000s, although the drivers are unclear. Here, we show that NO 3 -N concentrations also increased significantly in at least one season at 13 of 15 large southern Ontario tributaries (8.4 to 2779 km 2 ) that drain into Lake Ontario and have no known upstream wastewater treatment plants. Average NO 3 -N concentrations more than doubled between the 1970s and 2000s at some streams. Only the two most urbanized streams did not show any increase in NO 3 -N and NO 3 -N declined at the most urbanized catchment in this study (Sheridan Creek; 92% urban). Agriculture is the predominant form of human activity at the 13 watersheds where NO 3 -N increased, accounting for 51–71% of total land cover. Both the total area of agricultural land and the type of agriculture have changed dramatically in southern Ontario; and these shifts could alter nutrient transfer to waterways. Specifically, shifts in agriculture towards more N-demanding annual row crops like corn could result in higher NO 3 -N leakage to streams, and the impact of this form of land use change on nutrient export requires further investigation. Overall, these results suggest that changes in tributary loading may have contributed to recent observations of increasing NO 3 -N levels in offshore waters of Lake Ontario.

General Spatiotemporal Patterns of Urbanization: An Examination of 16 World Cities

Urbanization is the most dramatic form of land use change that has profoundly influenced environmental and socioeconomic conditions around the world. To assess these impacts and promote urban sustainability, a better understanding of urbanization patterns is needed. Recent studies have suggested several spatiotemporal patterns of urbanization, but their generality is yet to be adequately tested with long-term data. Thus, the main goal of our study was two-fold: (1) to examine the spatiotemporal patterns of urbanization of 16 world cities over a period of 200 years (1800–2000); and (2) to test four prominent hypotheses of urbanization patterns. Using a set of landscape metrics, we quantified temporal changes in the urban landscape pattern of the 16 cities and examined the four hypotheses individually. Our results show that these cities exhibit several common urbanization patterns: the urban landscape becomes compositionally more diverse, structurally more fragmented and geometrically more complex as urbanization progresses. Our study also suggests that urbanization is a process of shifting dominance among three urban growth modes: infilling, edge expanding and leapfrogging. However, idiosyncrasies do exist for individual cities, as detailed attributes of urbanization patterns often depend on the environmental and socioeconomic settings of cities. In addition, the choice of specific landscape metrics and the scales of analysis both influence the urbanization patterns revealed. Our study examined the urbanization patterns, for the first time, on long-term and global scales. The findings shed new light on the patterns and processes of urbanization, with implications for future studies of the ecology, planning and sustainability of cities.

Differential responses to woodland character and landscape context by cryptic bats in urban environments.

Urbanisation is one of the most dramatic forms of land use change which relatively few species can adapt to. Determining how and why species respond differently to urban habitats is important in predicting future biodiversity loss as urban areas rapidly expand. Understanding how morphological or behavioural traits can influence species adaptability to the built environment may enable us to improve the effectiveness of conservation efforts. Although many bat species are able to exploit human resources, bat species richness generally declines with increasing urbanisation and there is considerable variation in the responses of different bat species to urbanisation. Here, we use acoustic recordings from two cryptic, and largely sympatric European bat species to assess differential responses in their use of fragmented urban woodland and the surrounding urban matrix. There was a high probability of P. pygmaeus activity relative to P. pipistrellus in woodlands with low clutter and understory cover which were surrounded by low levels of built environment. Additionally, the probability of recording P. pygmaeus relative to P. pipistrellus was considerably higher in urban woodland interior or edge habitat in contrast to urban grey or non-wooded green space. These results show differential habitat use occurring between two morphologically similar species; whilst the underlying mechanism for this partitioning is unknown it may be driven by competition avoidance over foraging resources. Their differing response to urbanisation indicates the difficulties involved when attempting to assess how adaptable a species is to urbanisation for conservation purposes.

Fire and Parasites: An Under-Recognized Form of Anthropogenic Land Use Change and Mechanism of Disease Exposure.

Anthropogenic land use changes have altered ecosystems and exacerbated the spread of infectious diseases. Recent reviews, however, have revealed that fire suppression in fire-prone natural areas has not been recognized as a form of anthropogenic land use change. Furthermore, fire suppression has been an under-recognized mechanism altering the risk and transmission of infectious disease pathogens and host-parasite dynamics. However, as settlement patterns changed, especially due to colonial expansion in North America, Africa, and Australia, fire suppression became a major form of land use change which has led to broad-scale ecosystem changes. Because parasites of humans and animals can vector viral, bacterial, prion, fungal, or protozoan pathogens, concomitant changes associated with anthropogenic-induced changes to fire frequencies and intensities are of concern. I provide reference to 24 studies that indicate that restoring fire in natural areas has the potential to reduce ectoparasites without wings such as ticks, chiggers, fleas, and lice; ectoparasites with wings such as mosquitos, horn flies, face flies, and stable flies; and endoparasites affecting livestock and wildlife. This suggests that fire ecology and parasitology be considered as a priority area for future research that has implications for both humans and animals.

Changes in isotopic signatures of soil carbon and CO2 respiration immediately and one year after Miscanthus removal

AbstractThe removal of perennial bioenergy crops, such as Miscanthus, has rarely been studied although it is an important form of land use change. Miscanthus is a C4 plant, and the carbon (C) it deposits during its growth has a different isotopic signature (12/13C) compared to a C3 plant. Identifying the proportion of C stored and released to the atmosphere is important information for ecosystem models and life cycle analyses. During a removal experiment in June 2011 of a 20‐year old Miscanthus field (Grignon, France), vegetation was removed mechanically and chemically. Two replicate plots were converted into a rotation of annual crops, two plots had Miscanthus removed with no soil disturbance, followed by bare soil (set‐aside), one control plot was left with continued Miscanthus cultivation, and an adjacent field was used as annual arable crops control. There was a significant difference in the isotopic composition of the total soil C under Miscanthus compared with adjacent annual arable crops in all three measured soil layers (0–5, 5–10 and 10–20 cm). Before Miscanthus removal, total C in the soil under Miscanthus ranged from 4.9% in the top layer to 3.9% in the lower layers with δ13C values of −16.3 to −17.8 while soil C under the adjacent arable crop was significantly lower and ranged from 1.6 to 2% with δ13C values of −23.2. This did not change much in 2012, suggesting the accumulation of soil C under Miscanthus persists for at least the first year. In contrast, the isotopic signals of soil respiration 1 year after Miscanthus removal from recultivated and set‐aside plots were similar to that of the annual arable control, while just after removal the signals were similar to that of the Miscanthus control. This suggests a rapid change in the form of soil C pools that are respired.