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Mapping and understanding degradation of alpine wetlands in the northern Maloti-Drakensberg, southern Africa

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Journal of Mountain Science 2024年第9期21卷 2956-2966页

作者： johan van TOL Department of Soil Crop and Climate SciencesUniversity of the Free StateBloemfontein 9300South Africa

The alpine terrestrials of the Maloti-Drakensberg in southern Africa play crucial roles in ecosystem functions and livelihoods,yet they face escalating degradation from various factors including overgrazing and climate *** study employs advanced Digital Soil Mapping(DSM)techniques coupled with remote sensing to map and assess wetland coverage and degradation in the northern *** model achieved high accuracies of 96%and 92%for training and validation data,respectively,with Kappa statistics of 0.91 and 0.83,marking a pioneering automated attempt at wetland mapping in this *** attributes such as terrain wetness index(TWI)and valley depth(VD)exhibit significant positive correlations with wetland coverage and erosion gully density,Channel Network Depth and slope were negative *** density analysis revealed terrain attributes as dominant factors driving degradation,highlighting the need to consider catchment-specific susceptibility to *** challenge traditional assumptions which mainly attribute wetland degradation to external forces such as livestock overgrazing,ice rate activity and climate *** sensitivity map produced could serve as a basis for Integrated Catchment Management(ICM)projects,facilitating tailored conservation *** research should expand on this work to include other highland areas,explore additional covariates,and categorize wetlands based on hydroperiod and sensitivity to *** comprehensive study underscores the potential of DSM and remote sensing in accurately assessing and managing wetland ecosystems,crucial for sustainable resource management in alpine regions.

关键词： Digital Soil Mapping Gully density Integrated catchment management Remote sensing Wetland degradation

The origin of the suspended particulate matter in the seagrass meadow of tropical waters, an evidence of the stable isotope signatures

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Acta Oceanologica Sinica 2019年第1期38卷 136-143页

作者： A'an johan Wahyudi Afdal Research Center for Oceanography Indonesian Institute of Sciences

Suspended particulate matter(SPM) has been known as an important variable in the organic matter flow of coastal ecosystem. Half of burial carbon in seagrass meadows is contributed by allochthonous sources that compose the SPM such as phytoplankton, seagrass detritus, marine snow aggregates and terrestrially derived particles. Each composition of the SPM contributes different roles and is important to be identified, for instance,the exact contribution of seagrass detritus will be useful for determination of carbon export through the detritus form in seagrass meadows. Here, the SPM of seagrass meadows is studied in Bintan Island and the Selayar Archipelago. The aim of this research is to determine the source origin of the SPM using a stable isotope *** order to fulfill this aim, the objectives are defined as:(1) to specify the stable isotope signature(δ13C and δ15N)of the SPM, and(2) to determine the proportional distribution of the SPM's prospectus sources. The result shows that the possibility of the source origin of the SPM includes a seagrass fraction(Enhalus acoroides and Thalassia hemprichii), terrestrial C4 plant, macroalgae, and terrestrial C3 plant. The SPM lies between the marine-and terrigenous-end members. However, it seems that the SPM is more to be terrigenous-end and *** to a Bayesian mixing model, the terrestrial C4 has the highest contribution of the SPM at all sites except Barugaia and Pasi Island in Selayar(i.e., the highest contribution of the SPM is from the detritus of E. acoroides).The second contribution has been contributed by either seagrass detritus(E. acoroides or Th. hemprichii) or terrestrial C3 plant. The finding of this study indicates that there is a strong influence of the terrigenous sources in the SPM of the seagrass meadows.

关键词： suspended particulate matter stable isotope source origin seagrass ecosystems

Gut health,stress,and immunity in neonatal dairy calves:the host side of host-pathogen interactions

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Journal of Animal Science and Biotechnology 2021年第1期12卷 49-63页

作者： johan.S.Osorio Dairy and Food Science Department South Dakota State University113 H Alfred Dairy Science HallBrookingsSD 57007USA

The cumulative evidence that perinatal events have long-lasting ripple effects through the life of livestock animals should impact future nutritional and management recommendations at the farm level. The implications of fetal programming due to malnutrition, including neonatal survival and lower birth weights, have been characterized,particularly during early and mid-gestation, when placental and early fetal stages are being developed. The accelerated fetal growth during late pregnancy has been known for some time, while the impact of maternal stressors during this time on fetal development and by extent its postnatal repercussions on health and performance are still being *** stressors during late pregnancy cannot only influence colostrogenesis but also compromise adequate intestinal development in the fetus, thus, that further limits the newborn's ability to absorb nutrients, bioactive compounds, and immunity(i.e., immunoglobulins, cytokines, and immune cells) from colostrum. These negative effects set the newborn calf to a challenging start in life by compromising passive immunity and intestinal maturation needed to establish a mature postnatal mucosal immune system while needing to digest and absorb nutrients in milk or milk replacer. Besides the dense-nutrient content and immunity in colostrum, it contains bioactive compounds such as growth factors, hormones, and cholesterol as well as molecular signals or instructions [e.g., microRNAs(miRNAs) and long non-coding RNAs(lncRNAs)] transferred from mother to offspring with the aim to influence postnatal gut maturation. The recent change in paradigm regarding prenatal materno-fetal microbiota inoculation and likely the presence of microbiota in the developing fetus intestine needs to be addressed in future research in ruminants. There still much to know on what prenatal or postnatal factors may predispose neonates to become susceptible to enteropathogens(e.g., enterotoxigenic Escherichia coli), causing

关键词： Dairy calves Fecal RNA Neonatal diarrhea

Effects of local vegetation and plantation age for the parasitoid Asecodes mento- a biocontrol agent in organic strawberry fields

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Insect Science 2012年第5期19卷 604-608页

作者： johan A. Stenberg Department of Ecology Swedish University of Agricultural Sciences Uppsala Sweden

The parasitoid Asecodes mento （Walker, 1839）（Hymenoptera： Eulophidae） is the most important biocontrol agent of the strawberry leaf beetle Galerucella tenella （L.）（Coleoptera： Chrysomelidae） in northern Europe. Here, I investigated whether natural parasitism in organic strawberry plantations was affected by the presence of the alternative host plant meadowsweet （Filipendula ulmaria）, and whether parasitism rates differed between plantations of different ages （6 to 79 years）. I also investigated whether parasitoid brood size, body size and sex ratio differed between the two host plants in the field. Parasitism was very low （0%） in newly established plantations and increased to a plateau （~40%） in fields where strawberries had been grown for approximately 20 years or longer. Such an extended colonization process is unacceptable for commercial growers. It would thus be desirable to find a method to catalyze parasitoid population buildup in young plantations. Parasitoid brood sizes were larger in beetles collected from meadowsweet, while body size and sex ratio did not differ between parasitoids collected from the two plants. These findings suggest that meadowsweet can export parasitoids to neighboring strawberry fields. Although this is a possibility, I did not find any significant differences in parasitism rates between isolated strawberry fields and fields adjacent to meadowsweet stands, indicating that effects of local vegetation are small on parasitism rates. Releasing parasitoids in newly established strawberry plantations may be a better strategy for quickly obtaining high parasitism than intercropping with meadowsweet.

关键词： Asecodes mento biocontrol biological control Fragaria x ananassa,Galerucella tenella landscape ecology

Exhuming the Meso-Cenozoic Kyrgyz Tianshan and Siberian Altai-Sayan:A review based on low-temperature thermochronology

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Geoscience Frontiers 2016年第2期7卷 155-170页

作者： Stijn Glorie johan De Grave Centre for Tectonics Resources and Exploration(TRaX)Department of Earth SciencesSchool of Physical SciencesThe University of Adelaide Dept.Geology & Soil Science MINPET GroupGhent University

Thermochronological datasets for the Kyrgyz Tianshan and Siberian Altai-Sayan within Central Asia reveal a punctuated exhumation history during the Meso-Cenozoic. In this paper, the datasets for both regions are collectively reviewed in order to speculate on the links between the Meso-Cenozoic exhumation of the continental Eurasian interior and the prevailing tectonic processes at the plate margins. Whereas most of the thermochronological data across both regions document late Jurassic -Cretaceous regional basement cooling, older landscape relics and dissecting fault zones throughout both regions preserve Triassic and Cenozoic events of rapid cooling, respectively. Triassic cooling is thought to reflect the Qiangtang-Eurasia collision and/or rifting/subsidence in the West Siberian basin. Alternatively, this cooling signal could be related with the terminal terrane-amalgamation of the Central Asian Orogenic Belt. For the Kygyz Tianshan, late Jurassic-Cretaceous regional exhumation and Cenozoic fault reactivations can be linked with specific tectonic events during the closure of the Palaeo-Tethys and Neo-Tethys Oceans, respectively. The effect of the progressive consumption of these oceans and the associated collisions of Cimmeria and India with Eurasia probably only had a minor effect on the exhumation of the Siberian Altai-Sayan. More likely, tectonic forces from the east （present-day co- ordinates） as a result of the building and collapse of the Mongol-Okhotsk orogen and rifting in the Baikal region shaped the current Siberian Altai-Sayan topography. Although many of these hypothesised links need to be tested further, they allow a first-order insight into the dynamic response and the stress propagation pathways from the Eurasian margin into the continental interior.

关键词： Central Asia Tianshan Altai Sayan Thermochronology Exhumation Fault reactivation

Classification of Flat Lagrangian Surfaces in Complex Lorentzian Plane

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Acta Mathematica Sinica,English Series 2007年第12期23卷 2111-2144页

作者： Bang-Yen CHEN johan FASTENAKELS Department of Mathematics Michigan State University East Lansing MI 48824-1027 USA Departement Wiskunde Katholieke Universiteit Leuven Celestijnenlaan 200B B-3001 Leuven Belgium

One of the most fundamental problems in the study of Lagrangian submanifolds from Riemannian geometric point of view is to classify Lagrangian immersions of real space forms into complex space forms. The main purpose of this paper is thus to classify flat Lagrangian surfaces in the Lorentzian complex plane C1^2. Our main result states that there are thirty-eight families of flat Lagrangian surfaces in C1^2. Conversely, every flat Lagrangian surface in C1^2 is locally congruent to one of the thirty-eight families.

关键词： flat Lagrangian surfaces Lorentzian complex plane Legendre curve

Are flight paths of nocturnal songbird migrants influenced by local coastlines at a peninsula？

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Current Zoology 2014年第5期60卷 660-669页

作者： Cecilia NILSSON johan BACKMAN Thomas ALERSTAM Department of Biology Lund University SE-223 62 Lund Sweden

By recording nocturnally migrating passerines with tracking radar we have investigated how coastlines affect the migrants＇ flight paths. Birds could use coastlines as an orientation aid or as a reference cue to compensate for wind drift while mi- grating. However, on the small scale of Falsterbo Peninsula in southern Sweden, we found very little effect of coastlines on migrants flight paths, irrespective of altitude. We tracked 2 930 migrants in three autumn and two spring seasons, at altitudes from 60 up to 3 000 meters. We compared tracks of migrants flying in three different areas, which correspond to the three main coastlines, and can demonstrate that the orientation of the tracks did not differ in a way consistent with the coastlines between the areas in autumn, and showed only a slight effect in spring. This is in accordance with earlier infrared device monitoring in Falsterbo, but contrary to earlier visual observations. It supports the view of nocturnally migrating passerines as mainly broad-front migrants. Even though the coastlines on the scale of the peninsula affected the flight paths very little, it is possible that the coastline has an effect on a larger regional scale, by migrants avoiding long sea crossings and thereby being funneled towards the peninsula, but this remains to be investigated [Current Zoology 60 （5）： 660-669, 2014].

关键词： Bird migration Passerines Coastlines Leading lines Flight paths

Why People Live in Flood-Prone Areas in Akuressa, Sri Lanka

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International Journal of Disaster Risk Science 2018年第2期9卷 143-156页

作者： johan Askman Olof Nilsson Per Becker Division of Risk Management and Societal Safety Lund University

To investigate why people live in areas at high risk of floods, a qualitative case study was carried out in the areas around Akuressa, in southwest Sri Lanka. Data collection consisted mainly of semistructured interviews with local residents and government officials. The purpose was to study why people live in areas at high risk of floods, by looking beyond the purely physical aspects of living with hazards and exploring the underlying social factors. Four main factors were identified: an overall good living situation; a sense of place; difficulties relocating; and being well-adapted to the situation. The analysis also examined whether government officials shared the views of local residents. The findings highlighted both areas of consensus and discrepancies related to risk awareness, and the efficiency of risk reduction measures that had been implemented by the government. The case study identified and explored underlying social factors, such as risk normalization, risk trade-offs, and push-and-pull processes, which seem to influence the decision to live in a high-risk area.

关键词： Flood risk Risk awareness Risk perception Sri Lanka

Rock mass response for lined rock caverns subjected to high internal gas pressure

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第1期15卷 119-129页

作者： Davi Rodrigues Damasceno johan Spross Fredrik johansson Division of Soil and Rock Mechanics KTH Royal Institute of TechnologySE-10044StockholmSweden

The storage of hydrogen gas in underground lined rock caverns(LRCs)enables the implementation of the first fossil-free steelmaking process to meet the large demand for crude *** the response of rock mass is important to ensure that gas leakage due to rupture of the steel lining does not *** and numerical models can be used to estimate the rock mass response to high internal pressure;however,the fitness of these models under different in situ stress conditions and cavern shapes has not been *** this paper,the suitability of analytical and numerical models to estimate the maximum cavern wall tangential strain under high internal pressure is *** analytical model is derived in detail and finite element(FE)models considering both two-dimensional(2D)and three-dimensional(3D)geometries are *** models are verified with field measurements from the LRC in Skallen,southwestern *** analytical model is inexpensive to implement and gives good results for isotropic in situ stress conditions and large cavern *** the case of anisotropic horizontal in situ stresses,as the conditions in Skallen,the 3D FE model is the best approach.

关键词： Lined rock caverns(LRCs) High pressure Rock mass response In situ stress condition Cavern shape Gas storage