Spatial Heterogeneity of Forest-Steppes

A special issue of Forests (ISSN 1999-4907). This special issue belongs to the section "Forest Ecology and Management".

Deadline for manuscript submissions: closed (25 November 2020) | Viewed by 24234

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IEB (Institute of Ecology and Botany) Department of Terrestrial Ecology, MTA Centre Ecology Research, 2163 Vácrátót, Hungary
Interests: spatial heterogeneity; forest-steppes;, phytocoenology; floristical research; nature conservation

Special Issue Information

Dear Colleagues,

Forming a transitional zone between the closed forest and the treeless steppe belts, forest-steppes are among the most complex non-tropical ecosystems. Forest-steppes have an extremely high spatial heterogeneity of both environmental factors and plant communities. The long-term co-existence of various forest, scrub, and grassland communities results in high taxonomic and functional diversities at both the local and the landscape scales. Moreover, forest-steppes host numerous taxa of special conservation interest, including a high number of rare, endangered, or endemic species.

Unfortunately, forest-steppes belong to the most threatened biomes on Earth. Vast forest-steppe areas, especially in Europe and West Asia, have been turned into croplands and tree-plantations, while surviving forest-steppe fragments are usually extremely small.

Despite its enormous conservation importance, spatial heterogeneity has received relatively little scientific attention in forest-steppe ecosystems. The aim of this Special Issue of Forests is to contribute to a better understanding of the key role spatial heterogeneity plays in maintaining the high alpha, beta, and gamma diversities of forest-steppe landscapes, and to help effective conservation measures to ensure the maintenance of this unique ecosystem.

Dr. Laszlo Erdos
Guest Editor

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Keywords

  • forest-grassland mosaics
  • habitat complexity
  • landscape heterogeneity
  • semi-arid vegetation
  • wooded steppe
  • woodland

Published Papers (10 papers)

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Research

13 pages, 4035 KiB  
Article
Habitat Mosaics of Sand Steppes and Forest-Steppes in the Ipoly Valley in Hungary
by Ildikó Járdi, Dénes Saláta, Eszter S.-Falusi, Ferenc Stilling, Gergely Pápay, Zalán Zachar, Dominika Falvai, Péter Csontos, Norbert Péter and Károly Penksza
Forests 2021, 12(2), 135; https://0-doi-org.brum.beds.ac.uk/10.3390/f12020135 - 25 Jan 2021
Viewed by 1609
Abstract
The present study focuses on the mosaic-like occurrences of patches of steppes and fore-steppes in the Pannonian forest-steppe zone. We present the current vegetation, which is maintained including by human landscape use, i.e., grazing and mowing. The area is complex and for this [...] Read more.
The present study focuses on the mosaic-like occurrences of patches of steppes and fore-steppes in the Pannonian forest-steppe zone. We present the current vegetation, which is maintained including by human landscape use, i.e., grazing and mowing. The area is complex and for this reason it shows the changes in the landscape and differences in the vegetation more diversely. We wanted to answer the questions: Do sand steppes and forest-steppes occur in the Ipoly Valley and what location? What kind of environmental effects influence the species composition on these areas? Besides classic habitat mapping, are the satellite data from Sentinel-2A useful for distinction of different areas? Comparison of vegetation patches was based on the Hungarian habitat classification system (ÁNÉR). Based on satellite images, quantile data of the Normalized Vegetation Index (NDVI) were used for comparison. Based on the result, water bodies and urban areas are clearly distinguishable from other natural habitats. In some natural vegetation types, we found visible differences, such as grasslands, i.e., sandy steppe meadows and shrubby, woody vegetation patches. Sandy vegetation mainly grows on calcareous soils, which appear to be mosaic-like in the landscape on raised alluvials on the patches of past islands and reefs. From open to continuous closed grasslands, these vegetation types mainly grow on lithosoils. New occurrences of Pannonian sandy vegetation were discovered. In the sandy areas along the Ipoly Valley, open sandy grasslands were found, which is where the northernmost known occurrences of this vegetation type are. Besides common sandy grassland species, the vegetation also contains herbs that are typical in loess-grasslands and it is maintained by grazing, similarly to the eastern Pannonian area. This type of grazing can be useful when maintaining the mosaic-like appearance and diversity of the vegetation. Full article
(This article belongs to the Special Issue Spatial Heterogeneity of Forest-Steppes)
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15 pages, 2533 KiB  
Article
Do Sandy Grasslands along the Danube in the Carpathian Basin Preserve the Memory of Forest-Steppes?
by Károly Penksza, Dénes Saláta, Gergely Pápay, Norbert Péter, Zoltán Bajor, Zsuzsa Lisztes-Szabó, Attila Fűrész, Márta Fuchs and Erika Michéli
Forests 2021, 12(2), 114; https://0-doi-org.brum.beds.ac.uk/10.3390/f12020114 - 20 Jan 2021
Cited by 2 | Viewed by 1869
Abstract
Research highlights: In the present survey we examined the sandy grasslands appearing in the steppe-forest-steppe vegetation in the central part of the Carpathian Basin along the Danube. Background and objectives: We aimed to answer the following questions: Is it possible to build a [...] Read more.
Research highlights: In the present survey we examined the sandy grasslands appearing in the steppe-forest-steppe vegetation in the central part of the Carpathian Basin along the Danube. Background and objectives: We aimed to answer the following questions: Is it possible to build a picture of the past form of the vegetation through the examination of these vegetation units based on dominant grass taxa? Is Festuca wagneri an element of open grasslands or steppes? According to our hypothesis, these surveys can help reveal the original or secondary woody, shrubby patches through clarifying dominant taxa. Materials and Methods: We studied the grasslands in terms of coenology, putting great emphasis on the dominant Festuca taxa. Based on our preliminary surveys and literature, three vegetation types can be separated based on one single dominant Festuca taxon in each. The survey was conducted in four different locations in the Carpathian Basin. The cover of dominant grass species was used as an indicator value. The pedological background was also examined. Results: F. vaginata grassland is an open vegetation type based on its coenosystematic composition and ecological values. It grows in very weakly developed calcareous soil with sandy texture, with its lowest and highest organic carbon content ranging from 0.2% to 11.3% (0.2%), and the highest carbonate content (11.3%). Where the grasslands were disturbed, F. pseudovaginata and the recently discovered F. tomanii appeared. These taxa were also found in forest patches. The soil under F. pseudovaginata was more developed, in the surface horizon with higher organic carbon content (1.1%) and lower carbonate content (6.9%). The soil profile under F. wagneri developed the most, as the presence of deep and humus rich soil material from deflation and degradation showed. Conclusions: the dominant Festuca taxa of these vegetation types are good indicators of the changes in the vegetation and their ecological background. Full article
(This article belongs to the Special Issue Spatial Heterogeneity of Forest-Steppes)
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12 pages, 2711 KiB  
Article
Smaller and Isolated Grassland Fragments Are Exposed to Stronger Seed and Insect Predation in Habitat Edges
by Kitti Kuli-Révész, Dávid Korányi, Tamás Lakatos, Ágota Réka Szabó, Péter Batáry and Róbert Gallé
Forests 2021, 12(1), 54; https://0-doi-org.brum.beds.ac.uk/10.3390/f12010054 - 02 Jan 2021
Cited by 10 | Viewed by 3371
Abstract
Habitat fragmentation threatens terrestrial arthropod biodiversity, and thereby also leads to alterations of ecosystem functioning and stability. Predation on insects and seeds by arthropods are two very important ecological functions because of their community-structuring effects. We addressed the effect of fragment connectivity, fragment [...] Read more.
Habitat fragmentation threatens terrestrial arthropod biodiversity, and thereby also leads to alterations of ecosystem functioning and stability. Predation on insects and seeds by arthropods are two very important ecological functions because of their community-structuring effects. We addressed the effect of fragment connectivity, fragment size, and edge effect on insect and seed predation of arthropods. We studied 60 natural fragments of two grassland ecosystems in the same region (Hungarian Great Plain), 30 forest-steppes, and 30 burial mounds (kurgans). The size of fragments were in the range of 0.16–6.88 ha for forest-steppe and 0.01–0.44 ha for kurgan. We used 2400 sentinel arthropod preys (dummy caterpillars) and 4800 seeds in trays for the measurements. Attack marks on dummy caterpillars were used for predator identification and calculation of insect predation rates. In the case of seeds, predation rates were calculated as the number of missing or damaged seeds per total number of exposed seeds. Increasing connectivity played a role only in generally small kurgans, with a negative effect on insect and seed predation rates in the edges. In contrast, fragment size moderated edge effects on insect and seed predation rates in generally large forest-steppes. The difference between edges and centres was more pronounced in small than in large fragments. Our study emphasizes the important role of landscape and fragment-scale factors interacting with edge effect in shaping ecosystem functions in natural grassland fragments of modified landscapes. Managing functional landscapes to optimize the assessment of ecosystem functions and services needs a multispatial scale approach. Full article
(This article belongs to the Special Issue Spatial Heterogeneity of Forest-Steppes)
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16 pages, 2247 KiB  
Article
Wood Pastures: A Transitional Habitat between Forests and Pastures for Dung Beetle Assemblages
by László Somay, Viktor Szigeti, Gergely Boros, Réka Ádám and András Báldi
Forests 2021, 12(1), 25; https://0-doi-org.brum.beds.ac.uk/10.3390/f12010025 - 28 Dec 2020
Cited by 3 | Viewed by 2407
Abstract
Wood pastures are home to a variety of species, including the dung beetle. Dung beetles are an important functional group in decomposition. Specifically, in terms of livestock manure, they not only contribute to nutrient cycling but are key players in supporting human and [...] Read more.
Wood pastures are home to a variety of species, including the dung beetle. Dung beetles are an important functional group in decomposition. Specifically, in terms of livestock manure, they not only contribute to nutrient cycling but are key players in supporting human and animal health. Dung beetles, however, are declining in population, and urgent recommendations are needed to reverse this trend. Recommendations need to be based on solid evidence and specific habitats. Herein, we aimed to investigate the role of an intermediate habitat type between forests and pastures. Wood pastures are key areas for dung beetle conservation. For this reason, we compared dung beetle assemblages among forests, wood pastures, and grasslands. We complemented this with studies on the effects of dung type and season at three Hungarian locations. Pitfall traps baited with cattle, sheep, or horse dung were used in forests, wood pastures, and pasture habitats in spring, summer, and autumn. Dung beetle assemblages of wood pastures showed transient characteristics between forests and pastures regarding their abundance, species richness, Shannon diversity, assemblage composition, and indicator species. We identified a strong effect of season and a weak of dung type. Assemblage composition proved to be the most sensitive measure of differences among habitats. The conservation of dung beetles, and the decomposition services they provide, need continuous livestock grazing to provide fresh dung, as well as the maintenance of wood pastures where dung beetle assemblages typical of forests and pastures can both survive. Full article
(This article belongs to the Special Issue Spatial Heterogeneity of Forest-Steppes)
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17 pages, 13120 KiB  
Article
Possibilities of Speciation in the Central Sandy Steppe, Woody Steppe Area of the Carpathian Basin through the Example of Festuca Taxa
by Károly Penksza, Attila Csík, Anna Fruzsina Filep, Dénes Saláta, Gergely Pápay, László Kovács, Kristina Varga, János Pauk, Csaba Lantos and Zsuzsa Lisztes-Szabó
Forests 2020, 11(12), 1325; https://0-doi-org.brum.beds.ac.uk/10.3390/f11121325 - 14 Dec 2020
Cited by 3 | Viewed by 2022
Abstract
Research Highlights: We examined the vegetation appearing in forest-steppes in the Pannon region. In the present survey taxonomical relations of the dominant Festuca species were examined. Background and Objectives: After deforestation and shrubcutting bare soil patches exposed to anthropogenous effects provided an opportunity [...] Read more.
Research Highlights: We examined the vegetation appearing in forest-steppes in the Pannon region. In the present survey taxonomical relations of the dominant Festuca species were examined. Background and Objectives: After deforestation and shrubcutting bare soil patches exposed to anthropogenous effects provided an opportunity for new vegetation to form. Materials and Methods: Inflorescence parameters and micromorphological characters of the leaves were examined in a new taxon and compared with two, presumably closely related, species of the genus Festuca L. Festuca tomanii Korneck & T.Gregor, with silvery leaf surface, Festuca vaginata W. K. and Festuca pseudovaginata Penksza were compared based on 24 traits of the inflorescence and their leaf anatomy studied on leaf cross-sections. Moreover, leaf micromorphological features were compared using a stereomicroscope, a scanning electron microscope completed with Energy Dispersive X-Ray Spectroscopy measurements and phytolith analysis method to establish the taxonomic applications of the micromorphological characters of the epidermis. Results: The awns of the lemma of Festuca tomanii were shown to be longer than those of the two other species. Festuca vaginata and Festuca pseudovaginata specimen showed low variability in inflorescence parameters but inflorescence characters were not uniform because the panicle of Festuca tomanii individuals was found to be bigger in the northern part than the panicles originating from the southern part of the sampled area. The phytolith assemblages of the Festuca pseudovaginata and Festuca tomanii differ from the Festuca vaginata in the abundance of ELONGATE SINUATE phytolith morphotype. Conclusions: we confirmed the appearance of F. vaginata in natural grasslands and discovered new occurrences of F. pseudovaginata and F. tomanii. F. pseudovaginata inhabits only the Pannon region, we found endemic and natural stands of it, but in its secondary habitats it was confirmed as a completely new species. Furthermore, taxa of disturbed vegetations are currently being examined. These habitats are potential hotspots of speciation. Full article
(This article belongs to the Special Issue Spatial Heterogeneity of Forest-Steppes)
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16 pages, 6585 KiB  
Article
Does Shrub Encroachment Indicate Ecosystem Degradation? A Perspective Based on the Spatial Patterns of Woody Plants in a Temperate Savanna-Like Ecosystem of Inner Mongolia, China
by Xiao Wang, Lina Jiang, Xiaohui Yang, Zhongjie Shi and Pengtao Yu
Forests 2020, 11(12), 1248; https://0-doi-org.brum.beds.ac.uk/10.3390/f11121248 - 25 Nov 2020
Cited by 4 | Viewed by 2154
Abstract
Shrub encroachment, i.e., shrub emergence or an increase in woody plant cover, has been widely observed in arid and semiarid grasslands and savannas worldwide since the 2000s. However, until now, there has been a clear division of opinion regarding its ecological implications. One [...] Read more.
Shrub encroachment, i.e., shrub emergence or an increase in woody plant cover, has been widely observed in arid and semiarid grasslands and savannas worldwide since the 2000s. However, until now, there has been a clear division of opinion regarding its ecological implications. One view is that shrub encroachment is an indicator of ecological degradation, and the other is that shrub encroachment is a sign of the restoration of degraded ecosystems. This division leads to completely different judgments about the states and transition phases of shrub-encroached ecosystems, which further affects decisions about their conservation and management. To determine whether ecosystems experiencing shrub encroachment are degrading or are in a postdegraded restoration stage, the spatial distributions and interactions of woody plants after shrub encroachment were investigated in this study. An Ulmus pumila-dominated temperate savanna-like ecosystem with significant shrub encroachment in the Otindag Sandy Land, Inner Mongolia, China, was selected as the research area, and woody plants were surveyed within a 25-hectare (500 × 500 m) plot. Spatial point pattern analysis was employed to analyze the distribution patterns of the woody plants. The results indicated different patterns for U. pumila trees, i.e., a random distribution pattern for old trees (with a diameter at breast height (DBH) of more than 20 cm) and aggregated distribution patterns for medium (5 cm ≤ DBH < 20 cm) and juvenile trees (DBH < 5 cm) at scales of 0–9 and 0–12 m, respectively. For most shrubs, there was significant aggregation at a scale of 0–6 m. However, there were significant negative relationships between old U. pumila trees (DBH ≥ 20 cm) and most shrub species, such as Caragana microphylla and Spiraea aquilegifolia. In contrast, there were positive relationships between juvenile trees (DBH < 5 cm) and most shrub species. These results suggest that, to some extent, shrub encroachment may have disrupted the normal succession pattern in the U. pumila community in this area, and without conservation, the original tree-dominated temperate savanna-like ecosystem may continue to deteriorate and eventually become a shrub-dominated temperate savanna-like ecosystem. Full article
(This article belongs to the Special Issue Spatial Heterogeneity of Forest-Steppes)
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16 pages, 4166 KiB  
Article
Climate-Driven Holocene Migration of Forest-Steppe Ecotone in the Tien Mountains
by Ying Cheng, Hongyan Liu, Hongya Wang, Qian Hao, Yue Han, Keqin Duan and Zhibao Dong
Forests 2020, 11(11), 1139; https://0-doi-org.brum.beds.ac.uk/10.3390/f11111139 - 28 Oct 2020
Cited by 8 | Viewed by 2663
Abstract
Climate change poses a considerable threat to the forest-steppe ecotone in arid mountain areas. However, it remains unclear how the forest-steppe ecotone responds to climate change due to the limitation of the traditional pollen assemblages, which greatly limits the understanding of the history [...] Read more.
Climate change poses a considerable threat to the forest-steppe ecotone in arid mountain areas. However, it remains unclear how the forest-steppe ecotone responds to climate change due to the limitation of the traditional pollen assemblages, which greatly limits the understanding of the history of the forest-steppe ecotone. Here, we examined the Tien Mountains, the largest mountain system in the world’s arid regions, as a case study to explore the migration of the forest-steppe ecotone using the pollen taxa diversity, by combining modern vegetation surveys, surface pollen and two fossil pollen sequences—in the mid-elevation forest belt (Sayram Lake) and in the low-elevation desert belt (Aibi Lake). We found that the forest-steppe migration followed Holocene climate change. Specifically, the forest belt where Picea schrenkiana Fisch. & C.A.Mey. dominates has a very low pollen taxa diversity, characterized by high richness and low evenness, which plays a key role in mountainous diversity. By detecting the diversity change of the deposition sites, we found that in coping with the warm and wet middle Holocene, the forest belt expanded and widened as the observed diversities around the two lakes were very low, thus the forest-steppe ecotone moved downward accordingly. During the early and late Holocene, the forest belt and the forest-steppe ecotone moved upward under a warm and dry climate, and downward under a cold and wet climate, as there was a reduced forest belt effect on, or contribution to, the sites, and the observed diversities were high. Moisture loss may pose the greatest threat to the narrow forest-steppe ecotone, considering the climatic niche space and the limited living space for humidity-sensitive taxa. This study highlights that temperature and moisture co-influence the forest belt change, which further determines the position migration of the forest-steppe ecotone. Full article
(This article belongs to the Special Issue Spatial Heterogeneity of Forest-Steppes)
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16 pages, 4983 KiB  
Article
Fine-Scale Microclimate Pattern in Forest-Steppe Habitat
by Gabriella Süle, János Balogh, Szilvia Fóti, Bernadett Gecse and László Körmöczi
Forests 2020, 11(10), 1078; https://0-doi-org.brum.beds.ac.uk/10.3390/f11101078 - 09 Oct 2020
Cited by 4 | Viewed by 2381
Abstract
Microclimate and vegetation architecture are interdependent. Little information is available, however, about the fine-scale spatio-temporal relationship between the microclimate and herb layer of forest-steppe mosaics. In 2018 a three-season-long vegetation sampling and measurements of air temperature and air humidity were performed along 4 [...] Read more.
Microclimate and vegetation architecture are interdependent. Little information is available, however, about the fine-scale spatio-temporal relationship between the microclimate and herb layer of forest-steppe mosaics. In 2018 a three-season-long vegetation sampling and measurements of air temperature and air humidity were performed along 4 transects (44 m long each) in the herb layer with 89 dataloggers in the sandy region of Central Hungary, in a poplar grove and the surrounding open grassland. In order to improve data analysis, we introduced the use of a duration curve widely used in hydrology and proved to be useful in the processing of intensive climatic data. We analysed the effect of the direction and altitude of the solar irradiation and the edge effect on the microclimatic pattern. We also surveyed, seasonally, the spatial pattern of the exceedance rate for the vapour pressure deficit (VPD) in relation to the transect direction and to the edge of the grove. The exceedance rate for the VPD indicated considerable seasonal differences. The VPD exceedance rate indicates the stress effect for the vegetation. The moderating effect of the grove was small at 1.2 kPa VPD, but at 3.0 kPa—stronger stress—it was considerable. On the warmer side of the transects, mostly exposed at the south-eastern edge, the exceedance rate rose abruptly with distance from the edge compared to the gradual increase on the colder side. The cardinal and intercardinal directions as well as the altitude of the Sun all had influences on the moderating and shading effects of the grove. The southern edge was not always consistently the warmest. The distribution of the VPD values above the 3.0 kPa threshold varied within a seemingly homogeneous grassland, which highlights the importance of fine-scale sampling and analysis. This knowledge is valuable for assessing the dynamics and spatio-temporal patterns of abiotic factors and physiognomy in this type of ecosystem. Full article
(This article belongs to the Special Issue Spatial Heterogeneity of Forest-Steppes)
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12 pages, 13282 KiB  
Article
Divergent Hydraulic Strategies Explain the Interspecific Associations of Co-Occurring Trees in Forest–Steppe Ecotone
by Jingyu Dai, Hongyan Liu, Chongyang Xu, Yang Qi, Xinrong Zhu, Mei Zhou, Bingbing Liu and Yiheng Wu
Forests 2020, 11(9), 942; https://0-doi-org.brum.beds.ac.uk/10.3390/f11090942 - 28 Aug 2020
Cited by 7 | Viewed by 2243
Abstract
Research Highlights: Answering how tree hydraulic strategies explain the interspecific associations of co-occurring trees in forest–steppe ecotone is an approach to link plant physiology to forest dynamics, and is helpful to predict forest composition and function changes with climate change. Background and Objectives: [...] Read more.
Research Highlights: Answering how tree hydraulic strategies explain the interspecific associations of co-occurring trees in forest–steppe ecotone is an approach to link plant physiology to forest dynamics, and is helpful to predict forest composition and function changes with climate change. Background and Objectives: The forest–steppe ecotone—the driest edges of forest distribution—is continuously threatened by climate change. To predict the forest dynamics here, it is crucial to document the interspecific associations among existing trees and their potential physiological drivers. Materials and Methods: Forest–steppe ecotone is composed of forest and grassland patches in a mosaic pattern. We executed two years of complete quadrat surveys in a permanent forest plot in the ecotone in northern China, calculated the interspecific association among five main tree species and analyzed their hydraulic strategies, which are presented by combining leaf-specific hydraulic conductivity (Kl) and important thresholds on the stem-vulnerability curves. Results: No intensive competition was suggested among the co-occurring species, which can be explained by their divergent hydraulic strategies. The negative associations among Populus davidiana Dode and Betula platyphylla Suk., and P. davidiana and Betula dahurica Pall. can be explained as the result of their similar hydraulic strategies. Tilia mongolica Maxim. got a strong population development with its effective and safe hydraulic strategy. Generally, hydraulic-strategy differences can explain about 40% variations in interspecific association of species pairs. Oppositely, species sensitivity to early stages of drought is convergent in the forest. Conclusions: The divergent hydraulic strategies can partly explain the interspecific associations among tree species in forest–steppe ecotone and may be an important key for semiarid forests to keep stable. The convergent sensitivity to early stages of drought and the suckering regeneration strategy are also important for trees to survival. Our work revealing the physiological mechanism of forest compositions is a timely supplement to forest–steppe ecotone vegetation prediction. Full article
(This article belongs to the Special Issue Spatial Heterogeneity of Forest-Steppes)
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13 pages, 2379 KiB  
Article
Climatic, Edaphic and Biotic Controls over Soil δ13C and δ15N in Temperate Grasslands
by Xing Zhao, Xingliang Xu, Fang Wang, Isabel Greenberg, Min Liu, Rongxiao Che, Li Zhang and Xiaoyong Cui
Forests 2020, 11(4), 433; https://0-doi-org.brum.beds.ac.uk/10.3390/f11040433 - 10 Apr 2020
Cited by 8 | Viewed by 2444
Abstract
Soils δ13C and δ15N are now regarded as useful indicators of nitrogen (N) status and dynamics of soil organic carbon (SOC). Numerous studies have explored the effects of various factors on soils δ13C and δ15N [...] Read more.
Soils δ13C and δ15N are now regarded as useful indicators of nitrogen (N) status and dynamics of soil organic carbon (SOC). Numerous studies have explored the effects of various factors on soils δ13C and δ15N in terrestrial ecosystems on different scales, but it remains unclear how co-varying climatic, edaphic and biotic factors independently contribute to the variation in soil δ13C and δ15N in temperate grasslands on a large scale. To answer the above question, a large-scale soil collection was carried out along a vegetation transect across the temperate grasslands of Inner Mongolia. We found that mean annual precipitation (MAP) and mean annual temperature (MAT) do not correlate with soil δ15N along the transect, while soil δ13C linearly decreased with MAP and MAT. Soil δ15N logarithmically increased with concentrations of SOC, total N and total P. By comparison, soil δ13C linearly decreased with SOC, total N and total P. Soil δ15N logarithmically increased with microbial biomass C and microbial biomass N, while soil δ13C linearly decreased with microbial biomass C and microbial biomass N. Plant belowground biomass linearly increased with soil δ15N but decreased with soil δ13C. Soil δ15N decreased with soil δ13C along the transect. Multiple linear regressions showed that biotic and edaphic factors such as microbial biomass C and total N exert more effect on soil δ15N, whereas climatic and edaphic factors such as MAT and total P have more impact on soil δ13C. These findings show that soil C and N cycles in temperate grasslands are, to some extent, decoupled and dominantly controlled by different factors. Further investigations should focus on those ecological processes leading to decoupling of C and N cycles in temperate grassland soils. Full article
(This article belongs to the Special Issue Spatial Heterogeneity of Forest-Steppes)
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