Climate Regulation Services Research Articles

Urban expansion induced land use changes and its effect on ecosystem services in Addis Ababa, Ethiopia

The study examines the dynamics of urban expansion and changes in land use in Addis Ababa from 1993 to 2023 using satellite data and GIS analysis, as well as the benefit transfer approach for valuing ecosystem services. In addition, an expert survey was conducted using the analytical hierarchy process (AHP) method to determine the factors driving urban expansion. Results reveal oscillations in urban expansion rates and intensities over the three-decade period. While the 2003–2013 decade witnessed rapid urban growth, subsequent years showed a slowdown. The overall period (1993–2023) has an intensity index greater than 1, indicating that urban areas expanded faster than the city’s overall growth during the entire time frame. Land cover analysis revealed a significant decrease in green areas and croplands and a remarkable increase in built-up areas. In aggregate, the natural land cover was reduced by 128.6% whereas built-up increased by 224.7%. This shift signifies a transition from natural and agricultural land uses to urbanization and development. Moreover, the study evaluates changes in ecosystem service values (ESVs), indicating a consistent decline over time, particularly in forestlands and urban green areas. The significant alteration in land use that built up caused to ecosystems has resulted in an annual loss of 90.7 million USD from 1993 to 2023 in terms of ecosystem service value. The most significant impacts were observed in food production, climate regulation, and habitat ecosystem services. The encroachment of built-up areas on different land use categories leads to substantial losses in ecosystem service values. Socioeconomic factors, notably population growth and migration, emerge as primary drivers of urban expansion, emphasizing the interconnectedness of demographic changes and land use patterns. Overall, the findings underscore the complex interplay between urban expansion, land use dynamics, and ecosystem services in Addis Ababa, highlighting the importance of informed urban planning and policy interventions to mitigate adverse environmental impacts.

Assessing the carbon stock in the Alps: Considerations on three different approaches

Alpine protected areas provide a wide range of ecosystem services, with climate regulation being one of the most significant. In line with the European Biodiversity Strategy for 2030, which emphasizes the conservation and enhancement of ecosystem services, there is an urgent need to correctly manage these areas in order to maximize biodiversity conservation and the supply of ecosystem services. To achieve efficient management and decision-making processes, it is crucial to first assess the current supply of ecosystem services and to have a basic reference for monitoring activities. Various approaches can be used to evaluate the carbon storage, a widely used indicator of the climate regulation service. In this study three approaches were compared: fieldwork data collection, the Italian National Inventory and the TESSA toolkit. Discrepancies in the results emerged, in the Aosta Valley, TESSA reported 423 Gg for OC stock in mixed broadleaves, compared to 263 Gg from field data and 210 Gg from the National Inventory. Fieldwork data collection, while the most accurate, was the most time and resource intensive. The national inventory yielded values similar to fieldwork data; for example, in the Adamello spruce forest, the National Inventory reported 1838 Gg, while field data measured 1964 Gg. However, TESSA depicted qualitatively the same organic carbon stock distribution across the habitats compared to the other approaches. Based on the results, we propose different applications for these approaches, considering the advantages and disadvantages of each. Specifically, we suggest using the TESSA toolkit for preliminary and a qualitative screening of a study area to identify potential areas of interest for the carbon stock, while more precise but demanding approaches should be employed for local studies.

A priory allocation of ecosystem services to forest stands in a forest management context considering scientific suitability, stakeholder engagement and sustainability concept with multi-criteria decision analysis (MCDA) technique: A case study in Turkey

Various research endeavours are designed to identify ecosystem services, assess their spatial distribution, and prioritize them in a given forest landscape. The Turkish State Forest Organization has introduced an ecosystem-based multiple-use forest management philosophy since 2008, which emphasizes the need for identifying and allocating ecosystem services to each forest planning unit. This paper aims to investigate the use of Multiple Criteria Decision Analysis (MCDA) techniques and explores their effectiveness and suitability in identifying and allocating ecosystem services to forest units, considering scientific suitability, stakeholder engagement and the sustainability concept in the context of ecosystem-based forest management decision-making processes in a case study area of Turkey. We propose a framework that entails an iterative process comprising various stages, starting from identifying ecosystem services (ES) to allocating them to forest stands with a participatory approach. We employed the Analytical Hierarchy Process (AHP) and the Delphi method to determine stakeholder preferences and allocate ecosystem services to forest stands. This was achieved through an equation newly developed using scientific suitability, stakeholder preferences, and the sustainability concept. The landscape percentage allocated primarily to ES was as follows: water regulation (55.44%), soil protection (16.47%), biodiversity conservation (14.03%), wood production (13.08%), and aesthetic-recreation (0.84%). Notably, no allocations were made for national defence and climate regulation services. In conclusion, the stratification of Posof forests into zones was efficiently achieved a priori, considering both scientific-technical and socio-cultural criteria through MCDA techniques based on stakeholder preferences. This study streamlines the decision-making process involved in spatially allocating ecosystem services and provides crucial information instrumental in determining management objectives and optimal forest activities.

Land use transformation by urban informal settlements and ecosystem impact

The rapid expansion of informal settlements poses significant challenges to urban ecosystems and their services, a pressing issue that this study addresses by examining its impacts in Addis Ababa. This study delves into the impact of informal settlements on ecosystem services in Addis Ababa, comparing them with formal settlements. Utilizing geographic information systems (GIS) and remote sensing, it employed Landsat imagery, aerial photography, and base maps to track spatiotemporal changes and analyze trends. Through a GIS overlay approach, informal settlements and associated land use changes were identified, while the benefit transfer method assessed ecosystem service values. The findings revealed a significant increase in informal settlements on the city’s outskirts, expanding from 77 ha in 2009 (2% of the total area) to 765.6 ha in 2023 (21% of the total area). Nearly half (48.5%) of these informal settlements were established on previously natural land covers through encroachment. The research highlighted the ongoing conversion of agricultural land, forests, and urban green spaces into informal settlements, particularly on the city’s outskirts, leading to significant encroachment on these areas. This transformation caused an annual loss of $1,665,033.7 in ecosystem services from 2009 to 2023. Significant impacts were identified on food production, climate regulation, and habitat ecosystem services. Overall, the annual loss in ecosystem services due to land use changes amounted to $1,933,320.08. Informal settlements accounted for 86.1% of this total loss, highlighting the urgent need for targeted interventions to mitigate their disproportionate effects on ecosystem services. The study underscores the urgency of addressing the impact of informal settlements on ecosystem services through effective urban planning, sustainable land management practices, prevention of encroachment on natural land covers, and promotion of sustainable ecosystem management and utilization.

Analyzing NASA Satellite image dataset to track forest cover change over one year

This research paper aims to analyze the NASA Satellite image dataset in order to monitor and understand forest cover changes over the course of the past year. Forest cover change is a crucial environmental indicator, with implications for biodiversity, climate regulation, and ecosystem services. By employing advanced remote sensing techniques and machine learning algorithms, this study seeks to provide insights into the spatial and temporal patterns of forest cover change and its potential drivers. The research methodology involves data preprocessing, feature extraction, classification, change detection, and trend analysis. The results will contribute to a better understanding of the dynamics of forest ecosystems and support informed decision-making for sustainable land management. Keywords: Satellite imagery, forest cover change, remote sensing, data analysis, machine learning, classification, change detection.

Extreme weather characteristics and influences on urban ecosystem services in Wuhan Urban Agglomeration

In recent years, there has been a pronounced increase in the frequency of extreme weather events. To comprehensively examine the impact of extreme weather on ecosystem services within the Wuhan Urban Agglomeration (WUA), this study utilized meteorological station data, the Mann-Kendall (MK) test, and the Standardized Precipitation-Evapotranspiration Index (SPEI) to quantify the variation trends in heatwaves (HW) and droughts from 1961 to 2020. Then the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model was employed to evaluate and compare the differences in water yield and climate regulation ecosystem services under various HW, droughts, and HW-drought combination scenarios. The results show that over the past 60 years, the temperature, duration, and frequency of HW have significantly increased in the WUA. Specifically, the highest HW temperature, total HW days, HW frequency, and average HW temperature showed changing trend of +0.17 ℃/decade, +1.4 day/decade, +0.19 event/decade, and +0.07 ℃/decade, respectively. The year 2000 was identified as a mutation year for HW, characterized by increased frequency and heightened severity thereafter. The SPEI value exhibited an insignificant upward trend, with 1980 marked as a mutation year, indicating a decreasing trend in drought occurrences after 1980. Heatwaves have a weakening effect on both water yield and climate regulation services, while drought significantly weakened water yield and had a relatively modest effect on climate regulation. During HW-drought composite period, the average monthly water yield showed a notable discrepancy of 60 mm compared to humid years. Besides, as heatwaves intensify, the area of low aggregation for ecosystem services expands, whereas the area of high aggregation decreases. This study provides a preliminary understanding of the impact of urban extreme weather on urban ecosystem services under changing climatic conditions.

Forest Plot Decay Level Classification from ALS-Derived L-moments

Abstract. Forests play key roles in climate regulation and essential environmental services for living organisms. This is why forests are the central focus of the United Nations (UN) Sustainable Development Goal (SDG 15). Thus, effective forest management is critical for forest sustainability and preservation. Remote sensing advancements have improved forest mensuration leveraging cost and time, contrary to the field surveying approach. Often, field data is required to validate remotely sensed results. However, circumstances in the forest may render field data collection impossible. This study applied LiDAR-derived L-moments to directly estimate and classify five forest plot decay levels, to understand forest growth dynamics in the absence of field data. Two L-moment-based rules were tested and evaluated for classifying the plot decay levels from ALS height returns. Our findings show that the first rule (Lcv = 0.5) classified decay Levels 1 and 2 at Lcv < 0.5 and Levels 3 to 5 at Lcv > 0.5, while the second rule (Lskew = 0) classified decay Level 1 at Lskew < 0, and Levels 2 to 5 at Lskew > 0. This indicates that, while discriminating plot decay levels, the L-moment-based rules can classify healthy forest areas and areas of deadwood of varying decay levels directly from ALS height returns. This can be convenient for forest managers to exploit for classifying plot decay levels and for mapping areas of large gaps for planning forest resources for effective forest management. Furthermore, the approach can equally be significant for assessing forest biomass, biodiversity, and carbon stock.

Biodiversity management challenges: A policy brief

Global biodiversity has been lost at an alarming rate in the past century leading to what is often described as ‘the sixth mass extinction'. Leading causes of this loss are chemical pollution, habitat loss, unsustainable use of resources, invasive species, and climate change. Such environmental change can alter ecosystem functions irreversibly, leading to a direct loss of ecosystem services, such as food provision, climate regulation, and cultural services, which are estimated to have a global value of tens of trillions of dollars. International governing bodies have repeatedly set targets to preserve biodiversity and ecosystem services, especially within the framework of the UN Convention on Biological Diversity (CBD). Despite nation states’ pledges at the Rio Summit in 1992 to conserve biological diversity, progress has been lamentable. One reason for such failure is that action to redress biodiversity loss depends on national governments but it is of relatively low concern on the public agenda. This article reviews the UK and EU legal and policy biodiversity frameworks and exposes some of the complexities surrounding biodiversity loss, including non-compliance, public awareness, and valuation. Following a multidisciplinary roundtable on biodiversity in 2023, we suggest policy recommendations to overcome these issues.

Gross ecosystem product accounting in Miyun County: the supply and use of ecosystem services

The ability of an ecosystem to provide services differs from its actual consumption and use by human society. Overuse of ecosystems can degrade ecosystems. In order to evaluate the supply capacity and use status of the ecosystem in Miyun County, so as to better apply the ecosystem services to different policies and management, the supply and use of 10 types of ecosystem services in Miyun County were calculated by using value indicators, namely potential gross ecosystem product (GEP) and actual gross ecosystem product. The results show that: (1) In 2020, potential gross ecosystem product of Miyun County is 254.32 billion yuan, and actual gross ecosystem product is 53.28 billion yuan, accounting for 21% of the potential gross ecosystem product. (2) Among all kinds of ecosystem services, the contribution of water conservation services in potential gross ecosystem product is the highest, and the contribution of climate regulation services in actual gross ecosystem product is the highest. (3) The contribution of wetland was the highest in potential gross ecosystem product, while the contribution of forest was the highest in actual gross ecosystem product. (4) Natural ecosystem area and vegetation coverage are the main factors affecting potential gross ecosystem product, while actual gross ecosystem product is mainly affected by GDP and population. (5) By studying the potential supply and actual use of ecosystem services, we evaluated and distinguished between the services that ecosystem could produce and the services that were actually used by humans, and compared the supply capacity and actual use to assess the sustainability of ecosystem services, in order to formulate different policies and management measures for gross ecosystem product surplus and deficit regions. Potential gross ecosystem product could provide data support for the assessment of ecological protection benefits. Actual gross ecosystem product could be included in the system of national accounts, and as a standard for ecological compensation and ecological trading. Confusing potential supply and actual use in policy application would affect the effect of policy implementation, and distinguishing them could ensure policy implementation. The relative size of the relationship between the two could reflect the present and future levels of human well-being in a region. Both together provided management basis and policy-making support for guiding regional ecological protection and sustainable development.

Organic carbon accumulation in British saltmarshes

Saltmarshes are a crucial component of the coastal carbon (C) system and provide a natural climate regulation service through the accumulation and long-term storage of organic carbon (OC) in their soils. These coastal ecosystems are under growing pressure from a changing climate and increasing anthropogenic disturbance. To manage and protect these ecosystems for C and to allow their inclusion in emissions and natural-capital accounting, as well as carbon markets, accurate and reliable estimates of OC accumulation are required. However, globally, such data are rare or of varying quality. Here, we quantify sedimentation rates and OC densities for 21 saltmarshes in Great Britain (GB). We estimate that, on average, saltmarshes accumulate OC at a rate of 110.88 ± 43.12 g C m−2 yr−1. This is considerably less than widely applied global saltmarsh averages. It is therefore highly likely that the contribution of northern European saltmarshes to global saltmarsh OC accumulation has been significantly overestimated. Taking account of the climatic, geomorphological, oceanographic, and ecological characteristics of all GB saltmarshes and the areal extent of different saltmarsh zones, we estimate that the 451.65 km2 of GB saltmarsh accumulates 46,563 ± 4353 t of OC annually. These low OC accumulation rates underline the importance of the 5.20 ± 0.65 million tonnes of OC already stored in these vulnerable coastal ecosystems. Going forward the protection and preservation of the existing stores of OC in GB saltmarshes must be a priority for the UK as this will provide climate benefits through avoided emissions several times more significant than the annual accumulation of OC in these ecosystems.

Land Use/Cover-Related Ecosystem Service Value in Fragile Ecological Environments: A Case Study in Hexi Region, China

The monetary value assigned to ecosystems and their essential goods and services is known as ecosystem service value (ESV). Fragile ecological environments, susceptible to climate change and human disturbances, require significant ecological protection. This protection is vital not only for stabilizing socio-economic conditions but also for fostering a positive feedback loop within natural systems. Looking ahead, identifying priority conservation areas and regions of particular concern in fragile environments based on ESV changes is a proactive approach. Until now, current studies on ESV in fragile ecological environments have been insufficient, falling short of adequately serving the purpose of ecological protection in such areas. The Hexi region (HXR), situated in the interlaced area of the Qilian Mountains and the Alxa Plateau in northwest China, possesses a fragile ecological environment. Due to the intricate interactions between humans and the environment, it stands out as a crucial area for studying ecosystem services in fragile habitats. Hence, this study aims to systematically analyze the ESV in the HXR over the past 30 years. Here, the values of 11 ecosystem service categories in HXR during 1990–2020 were calculated, clarifying their spatiotemporal difference and dynamic changes based on land use/cover (LULC) products for years 1990, 1995, 2000, 2005, 2010, 2015, and 2020, using an improved equivalent factors method. The findings revealed that the unit standard equivalent factor is 1.51 × 105 CNY·km−2·a−1, and the total ESV value has grown from CNY 182.50 to 185.48 billion from 1990 to 2020. Hydrologic regulation, climate regulation, and soil conservation service values are the principal single ESV categories across HXR. Over the past three decades, ESV changes in HXR have been primarily driven by water area, grassland, and wetland, with the sensitivity of ESV to LULC generally increasing (0.15~9.10%). Natural forcing and anthropogenic perturbations have combined to cause changes in LULC in HXR, influencing ESV fluctuations. Future ecosystem protection activities in HXR should prioritize the maintenance of grasslands, water regions, and wetlands to ensure the preservation of ESV. This study clarifies the impacts of LULC change on ESV in fragile natural environments and highlights the significance of focusing on ESV changes for the health promotion of natural-social systems. The findings provide a foundation for constructing a sustainable development model that is in harmony with both people and the environment.

Exploring the complex trade-offs and synergies of global ecosystem services

The trade-off and synergy relationship of ecosystem services is an important topic in the current assessment. The value of each service provided by the ecosystem is substantially affected by human activities, and conversely, its changes will also affect the relevant human decisions. Due to varying trade-offs among ecosystem services and synergies between them that can either increase or decrease, it is difficult to optimize multiple ecosystem services simultaneously, making it a huge challenge for ecosystem management. This study firstly develops a global Gross Ecosystem Product (GEP) accounting framework. It uses remote sensing data with a spatial resolution of 1 km to estimate the ecosystem services of forests, wetlands, grasslands, deserts, and farmlands in 179 major countries in 2018. The results show that the range of global GEP values is USD 112–197 trillion, with an average value of USD 155 trillion (the constant price), and the ratio of GEP to gross domestic product (GDP) is 1.85. The trade-offs and the synergies among different ecosystem services in each continent and income group have been further explored. We found a correspondence between the income levels and the synergy among ecosystem services within each nation. Among specific ecosystem services, there are strong synergies between oxygen release, climate regulation, and carbon sequestration services. A trade-off relationship has been observed between flood regulation and other services, such as water conservation and soil retention services in low-income countries. The results will help clarify the roles and the feedback mechanisms between different stakeholders and provide a scientific basis for optimizing ecosystem management and implementing ecological compensation schemes to enhance human well-being.

Quantification of ecosystem service value and its guidance to land use strategy in Loess Plateau region: A case study of Qingyang City

Abstract Alterations in land use strategies significantly influence regional sustainable development, affecting ecosystem service functions, surface energy balance, and biodiversity. This study explores the impact of ecosystem service values on land use within Qingyang City, situated in the Loess Plateau. We employ an index system to assess ecosystem services at the Loess Plateau across four dimensions—supply, regulation, culture, and support. Utilizing physical and ecological value equivalent factors, we quantify these indices and the value of Qingyang City’s ecological service system. Specifically, the ecosystem equivalent factors for sloped cropland and terraced fields in Qingyang City are quantified as 1.1545 and 1.9788, respectively. Our findings reveal that ecosystem services significantly influence land use; notably, cropland and grassland, which collectively provide approximately 98% of climate regulation services, have experienced a reduction in their total climate regulation capacity by −14.19% and −9.42%, respectively, from 2010 to 2020. This reduction highlights a marked weakening in the climate regulatory capabilities of these land types, underscoring the need for Qingyang City to reassess and adjust its land use strategies to enhance the climate regulation service capacities of cropland and grassland.

Based on ecological footprint and ecosystem service value, research on ecological compensation in Anhui Province, China

Anhui Province plays a significant ecological role and acts as a “ecological barrier” in the Yangtze River Delta ecological integration project. In order to study numerous aspects impacting the balance between economy and environment, this article uses Anhui Province as the research object and analyzes each ecosystem from three dimensions: ecosystem service value, ecological footprint, and ecological carrying capacity. On this basis, the amount of ecological compensation is calculated to provide a foundation for the coordination of environmental rights and ecological protection in Anhui Province. These are the findings: (1) Anhui Province's ecosystem service value in 2021 was 731.874 billion yuan, which was comparatively high. Among them, the contribution of ecosystem service value was mainly made by waters and forest, which together provided 90.35% of the province's value and were the key ecosystems that need to be protected. Among the main functions of the ecosystem service, the value of regulating service and its secondary functions, such as hydrologic regulation, climate regulation and environmental purification services, had always accounted for the largest proportion among all services, indicating that regulating service played a significant part in Anhui’s ecosystem. (2) Anhui Province's ecological footprint in 2021 was approximately 115.7417 million hectares, with a total ecological carrying capacity of approximately 10.7757 million hectares. Anhui was actually in an ecological deficit situation. Among them, the ecological deficit of cultivated land and fossil energy land were the most serious. In the future, reasonable measures must be taken to adjust the state of these two ecosystems, and ultimately realize the province of Anhui's total ecological sustainability. (3) Anhui Province's ecological overload index for 2021 was −9.74, the province's overall resources supply and demand were significantly out of balance, and negative environmental benefits were exported, and an ecological compensation payment of roughly 3706.795 billion yuan was necessary.

Assessment of forest cover and forest loss using satellite images in Thua Thien Hue province, Vietnam

Deforestation in the tropics continues inexorably with severe implications for biodiversity conservation, climate regulation and ecosystem services. This study investigated variation in forest cover in Thua Thien Hue province, Vietnam, using the Landsat Thematic Mapper and Operational Land Imager satellite images over the period 1989–2021. Imageries were classified using the maximum likelihood classification technique for the years 1989, 2006, and 2021 and were evaluated for accuracy using the kappa coefficient for each year. Furthermore, forest cover losses and gains were evaluated using the Normalized Difference Vegetation Index and Soil Adjusted Vegetation Index, which were compared with the output of the supervised classification. Results showed that the forest cover of Thua Thien Hue province has drastically declined over the years. The forest cover, which was estimated at 68.88% (3461.46 km2) of the total land area in 1989, increased to 69.04% (3469.51 km2) in 2006 and subsequently decreased to 57.55% (2891.81 km2) in 2021. Severely reduced forest cover is often associated with the expansion of agriculture on the forest edge; other contributing factors include logging, illegal production land, and forest fires. Overall, our results show the necessity of forest management, rational land-use planning policy, and increased community awareness of conservation and sustainable development of forest resources in the study area in the future.

Soil climate regulation services: high SOC stock in Podzols and Umbrisols in an alpine grassland (Valle Adamé, Italy)

The United Nations Sustainable Development Goals include soil conservation as an urgent climate action to be taken; alpine grassland soils, rich in organic matter and particularly vulnerable to climate change, require special attention. In the upper Adamé valley (Italy), the effects of soil and vegetation types and environmental parameters, on soil carbon (SOC) stock and other soil properties were evaluated. Sampling points were chosen starting from the main vegetation types (dominant species: Rhododendron ferrugineum, Nardus stricta, Festuca luedii, Adenostyles leucophylla and Salix herbacea). For each vegetation type, five plots were selected, within which three soil minipits were described and sampled by layers (0–10 cm, 10–20 cm and 20–40 cm), at 75 georeferenced points. The results highlighted that: (1) Podzols and Umbrisols showed high capacity to store OC in the top 40 cm (17.3 ± 8.2 kg m−2), whereas Fluvisols and Leptosols demonstrated a low capacity (5.0 ± 3.5 kg m−2); (2) topographical factors indirectly affected the variability of the SOC stock by influencing the spatial distribution of vegetation; (3) 74% of the SOC stock was sequestered in the upper 0–20 cm layer; (4) regardless of soil type, Festuca and Salix were the vegetation types that mostly contributed to the surface SOC enrichment, followed by Rhododendron, Nardus and Adenostyles. Following climate change, a shift of the Salix and Nardus vegetation types in favour of the Rhododendron type is expected in the short to medium term. As a consequence, a possible reduction in the effectiveness of the climate regulation service provided by the soils may occur.

Assessment of ecosystem services for climate regulation: case study of the Madu Ganga wetlands

The ecosystem services assessment plays one of the key role in the modern concept of sustainable development, including combat climate change and achievement carbon neutrality, since the value assessment of all benefits and risks from ecosystem services is the most visible for decision makers (business and government). Mangrove forests in developing countries, such as Sri Lanka, are important factor in achieving carbon neutrality. The purpose of present investigation was the economic assessment of climate regulation services on the example of the Madu Ganga wetlands (Sri Lanka). The carbon stock was calculated as the marginal cost of reducing carbon emissions, and the sequestration was assessed through the calculation of the carbon social cost or the marginal cost of damage. As a result, the high cost of carbon storage by the Madu Ganga wetlands was revealed - approximately, it amounted to $153,341,221. The cost of the ES for carbon sequestration was $2,153,424. The total cost of services to regulate the carbon cycle of the Madu Ganga wetlands was $155,494,645, or 0.18% of the nominal GDP of the island of Sri Lanka for 2021. The high value of the mangrove forests of Madu Ganga shows their crucial role in achieving carbon neutrality within the framework of the concept of sustainable development.

Ecosystem services of lake-wetlands exhibit significant spatiotemporal heterogeneity and scale effects in a multi-lake megacity

Climate change and anthropogenic disturbances are altering global lake-wetlands (LWs) and their ecosystem services (ESs), posing a threat to sustainable development. Understanding the spatiotemporal heterogeneity and scale effects of LWESs has risen to be a critical concern in the sustainable management of wetlands. Although the LWESs of large lakes or at the macro-region are well documented, their complexity in urbanizing areas remains to be further addressed. Here we aim to reveal the spatiotemporal heterogeneity and scale effects of LWESs under the coinciding effects of wetland conservation and urbanization through a study in Wuhan, a multi-lake city of central China. The LWESs and their spatiotemporal variations from 1999 to 2019 were characterized by nine indicators based on time-series remote-sensing images and statistical data. A V-shaped trend was observed in the area of the LWs over time, which decreasing by 8.12% in 1999–2010 while recovering by 9.57% in 2010–2019. The LW loss in the main urban area (MA) was mainly encroached by construction lands, while the restoration of croplands to LWs in the rural area (RA) completely offsets the loss of LWs. We found that the change rates of most LWESs were more severely degraded along a rural–urban gradient, except for cultural services. Specifically, the water supply (-57.39%), flood regulation (-34.19%), climate regulation (-31.36%), and biodiversity conservation (-62.13%) services were the most severely damaged in LWs in the MA. However, the carbon sink services of LWs in the RA suffer the most severe degradation. Not only with spatiotemporal heterogeneity but LWESs also showed obvious scale effects. The larger the LWs, the higher the ES capacity tends to be. Smaller LWs were heavily encroached, with the worst ES capacities. These results highlight that LW conservation should no longer be homogeneous, but should combine indicators of scale effects and spatial heterogeneity. Due to land resource constraints, those close to urban center should improve regulating and supporting service capacities, while further away, improvements in area and LWESs can be pursued to balance the demand growth. Further, it is important to conserve existing and small LWs from over-encroachment.

Identification of a wetland ecological network for urban heat island effect mitigation in Changchun, China

The rapid development of cities has led to severe fragmentation of wetland landscapes, destroying their ecological function in climate regulation. However, most studies on the climate regulation services of wetlands focused on isolated wetland units, ignoring the overall function of wetland networks. The climate regulation function of wetlands can be improved by integrating fragmented wetland resources and building a stable wetland network. A case study was carried out in Changchun City, China, to improve the method of identifying ecological networks by considering the network energy flows. First, morphological spatial pattern analysis and landscape connectivity index combined with the wetland cooling index were used to identify ecological sources with high cooling capacity, and an ecological resistance surface was constructed with surface temperature as the main factor. The minimum cumulative resistance model was then used to identify the ecological network, which was then optimized by integrating patches as stepping stones to form the optimized ecological network. Finally, the importance of ecological corridors was evaluated by identifying ventilation corridors and integrated with the complex network theory to determine the ecological network robustness. We found that the degree of fragmentation in the studied wetlands was relatively high, and that construction of an ecological network with patches as stepping stones can improve its robustness. Each component in the ecological network had a high potential to mitigate the urban heat island effect, which can be further promoted by ecological corridors with high ventilation potential. Mutations in ecological nodes that cause network robustness played a key role in maintaining ecological network stability. This improved methodology effectively improves the scientific and practical application of wetland networks to mitigate the urban heat island effect and provides regions facing the contradiction of rapid development and wetland protection with strategies to reduce the threat of this effect.

Variation in methodology obscures clarity of cropland global warming potential estimates.

Global warming potential (GWP) estimates from agroecosystems are valuable for understanding management effects on climate regulation services. However, GWP estimates are complex, including attributes with high spatiotemporal variability. Published GWP estimates from cropland were compiled and methodological attributes known to influence GWP were extracted. Results revealed considerable variation in approaches to estimate GWP. Among carbon balance methods, respiration methods were used most frequently (33%), followed by soil carbon stock change over time (30%). Twenty-six percent of studies did not account for carbon change in GWP estimates. Duration of gas flux measurements ranged from 0.5 to 60 months, with weekly and sub-weekly sampling most common (34% and 33%, respectively). Carbon dioxide equivalent conversion factors generally aligned with Intergovernmental Panel on Climate Change recommendations through 2014 but diverged thereafter. This review suggests the need for increased transparency in how GWP estimates are derived and communicated. Presentation of key metadata alongside GWP estimates is recommended.