Koedoe最新文献

{"title":"First report of various Fusarium species from the Stevenson-Hamilton Supersite granite catena system in the Kruger National Park, South Africa","authors":"M. Gryzenhout, M. Vermeulen, Gilmore T. Pambuka, Riana Jacobs","doi":"10.4102/koedoe.v62i2.1599","DOIUrl":"https://doi.org/10.4102/koedoe.v62i2.1599","url":null,"abstract":"The Kruger National Park (KNP) covers the north-eastern part of southern Africa (Carruthers 2017) and is also linked with the Gonarezhou National Park (Zimbabwe) and the Limpopo National Park (Mozambique) as the Great Limpopo Transfrontier Park. The KNP is part of the Kruger to Canyons Biosphere area designated by the United Nations Educational, Scientific and Cultural Organization (UNESCO) as an International Man and Biosphere Reserve (the ‘Biosphere’) (http://www.unesco.org/new/en/natural-sciences/environment/ecologicalsciences/biosphere-reserves/africa/south-africa/kruger-to-canyons/). The StevensonHamilton Supersite, where this study was conducted, is part of four research ‘supersites’ in the KNP, with each representing distinct geological, climatic and linked biodiversity patterns (Smit et al. 2013).","PeriodicalId":48892,"journal":{"name":"Koedoe","volume":"12 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90756460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A tribute to Frederick (Fred) J. Kruger","authors":"W. Swart, M. Seaman, Pieter AL Le Roux, B. Janecke","doi":"10.4102/koedoe.v62i2.1639","DOIUrl":"https://doi.org/10.4102/koedoe.v62i2.1639","url":null,"abstract":"","PeriodicalId":48892,"journal":{"name":"Koedoe","volume":"21 Sup12 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88683607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrological response in a savanna hillslope under different rainfall regimes","authors":"J. Tol, S. Julich, D. Bouwer, E. Riddell","doi":"10.4102/koedoe.v62i2.1602","DOIUrl":"https://doi.org/10.4102/koedoe.v62i2.1602","url":null,"abstract":"Savannas are currently experiencing extensive population and agricultural water resource pressure globally (Rockström et al. 2014). Because we are now moving into an era of adaptive management of ecosystems where information on state change thresholds is a prerequisite for their sustained management, it is necessary to invest in understanding the biophysical processes that maintain these systems. In savanna landscapes, soil water is the direct link between precipitation and ecological patterns (Weltzin et al. 2003). The co-domination by trees and grasses is bound by soil water availability, a key factor in establishing form and function. Therefore, spatial soil moisture dynamics is a crucial link in the equilibrium between climate, soil and vegetation in these systems (Rodriguez-Iturbe et al. 1999). The resulting hydrological processes contribute to the biophysical template of these semi-arid systems, controlling the distribution of water and other resources along a continuum within the landscape, which often comprises compound effects of non-linear relationships and thresholdtriggered responses. Given this complexity, novel interdisciplinary approaches should be sought to understand hydrological processes in such heterogeneous landscapes (Troch et al. 2008). Moreover, inter-disciplinarity is increasingly valuable for successful landscape management, given the emphasis on hydrological connectivity at landscape scale (Michaelides & Chappell 2009).","PeriodicalId":48892,"journal":{"name":"Koedoe","volume":"83 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81078459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of hydropedological flowpaths in Stevenson–Hamilton catena from soil morphological, chemical and hydraulic properties","authors":"D. Bouwer, P. L. Roux, J. Tol","doi":"10.4102/koedoe.v62i2.1584","DOIUrl":"https://doi.org/10.4102/koedoe.v62i2.1584","url":null,"abstract":"Soil acts as a first-order control in the portioning of hydrological flowpaths and governing residence periods of water in a landscape. Water, on the other hand, is a primary agent in soil formation and leaves unique soil morphological signatures of water movement and storage. This interactive relationship between soil and water serves as the basis for a relatively new, interdisciplinary field of study called hydropedology (Lin 2010; Lin et al. 2006a). This synergistic research field promotes a more integrated approach to address complex issues regarding water resource management in variable water regimes of semi-arid landscapes (Kutílek & Nielsen 2007; Lin 2003; Lin et al. 2006b). Hydropedological studies at landscape scale typically include various components of the hydrological cycle and recognise the intimate relationship between surface and groundwater at various spatiotemporal scales (Van Tol & Lorentz 2018).","PeriodicalId":48892,"journal":{"name":"Koedoe","volume":"3 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90188085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Groundwater–surface water interactions in an ephemeral savanna catchment, Kruger National Park","authors":"E. Riddell, J. Nel, J. V. van Tol, D. Fundisi, Faith Jumbi, Ashton Van Niekerk, S. Lorentz","doi":"10.4102/koedoe.v62i2.1583","DOIUrl":"https://doi.org/10.4102/koedoe.v62i2.1583","url":null,"abstract":"The semi-arid conditions in savanna landscapes ensure that ephemeral drainage dominates the hydrological network in these dryland systems. Quantification of their hydrological processes is important to inform ecosystem understanding and future conservation efforts under a changing climate, and to provide guidance for restoration. By combining in situ hydrometric observations, hydrochemistry, remote sensing and a soil water balance model, we characterise the groundwater–surface water interactions in ephemeral low-order catchments of the granitoid regions of the southern Kruger National Park (KNP). Streams at the lowest orders are augmented by lateral interflows from the catena, although the second- and third-order stream reaches are conduits for groundwater recharge to the fractured rock aquifer; the soils of the crests and foot-slopes also show preferential flow, and are truly recharge soils, whilst the duplex soils of the midslopes clearly show their responsive nature to a low soil moisture deficit in the shallow horizons. Actual evaporation (aET) differed between catena elements with surprisingly little variation at third-order hillslopes, with the greatest overall aET at the first order. Meanwhile, soil water balances demonstrated a significant variation in storage of the riparian zones as a result of interflow from upslope and aET losses. Furthermore, data support broader-scale observations that groundwater recharge through the vadose zone to the fractured rock aquifer is dependent upon threshold antecedent precipitation conditions. Moderate precipitation events (5 mm/day – 35 mm/day) over a 2–3 week period initiate groundwater responses with a 2–3 month lag, whilst intense precipitation events (100 mm/day) are expressed within 2–3 weeks.Conservation implications: Understanding the lateral connectivity of terrestrial ecosystems to the ephemeral drainage network expressed via hydrological processes in these savanna landscapes is important to infer potential impacts of climate variability on the continued conservation of these ecosystems, both within and external to protected areas.","PeriodicalId":48892,"journal":{"name":"Koedoe","volume":"75 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86284664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A tribute to Pieter Johannes (Johann) du Preez","authors":"Leslie R. Brown, Andri C. van Aardt, Beanelri B. Janecke","doi":"10.4102/koedoe.v62i2.1640","DOIUrl":"https://doi.org/10.4102/koedoe.v62i2.1640","url":null,"abstract":"","PeriodicalId":48892,"journal":{"name":"Koedoe","volume":"43 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73750773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fungal community structure variability between the root rhizosphere and endosphere in a granite catena system in Kruger National Park, South Africa","authors":"M. Gryzenhout, E. Cason, M. Vermeulen, George A.E. Kloppers, Brooke Bailey, Soumya Ghosh","doi":"10.4102/koedoe.v62i2.1597","DOIUrl":"https://doi.org/10.4102/koedoe.v62i2.1597","url":null,"abstract":"Soils harbour a great diversity of fungal species that have various ecological functions (Bridge & Spooner 2001; Havlicek & Mitchell 2014). Saprophytic fungi break down dead organic matter and, in turn, fertilise the soil (Setala & McLean 2004). Certain plant fungal pathogens are specifically adapted to infect plants through roots and to spread or survive in soils, while some pathogens affecting tissues of plants growing above the soil also have the ability to survive in soils. Propagules of more specialised below-ground fungi, such as mycorrhiza that form specialised root associations benefitting plant health, can also be found in surrounding soils (Moore, Robson & Trinci 2011). Similarly, propagules of various fungi occurring in different niches and substrates above ground can also be found in soils (Aylor 2003; Taylor & Bruns 1999).","PeriodicalId":48892,"journal":{"name":"Koedoe","volume":"4 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83617775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The rhizobiome of herbaceous plants in Clovelly and Sterkspruit soils of the Stevenson–Hamilton supersite","authors":"M. Vermeulen, E. Cason, W. Swart","doi":"10.4102/koedoe.v62i2.1596","DOIUrl":"https://doi.org/10.4102/koedoe.v62i2.1596","url":null,"abstract":"The rhizosphere is characterised by high microbial activity and an array of complex and dynamic physical, chemical and biological interactions termed the ‘rhizosphere effect’ (Helliwell et al. 2019; Hiltner 1904). These interactions play a crucial role in plant nutrition (Raaijmakers et al. 2009; Sørensen 1997) and ecosystem functioning in terrestrial ecosystems (Singh et al. 2004). Microbes associated with the rhizosphere (i.e. the rhizosphere microbiome or rhizobiome) represent a vast reservoir of microbial diversity that includes fungi, bacteria, nematodes, protozoa, algae, viruses and arthropods (Berg & Smalla 2009; Bonkowski et al. 2000; Bonkowski, Villenave & Griffiths 2009; Bulgarelli et al. 2013). Plant species actively determine the composition of their rhizobiome by secreting root exudates that attract or repel specific bacteria from the surrounding bulk soil (Berg & Smalla 2009; Doornbos, Van Loon & Bakker 2012). The composition of the rhizobiome is thus determined by numerous edaphic variables of the immediately surrounding bulk soil such as the soil mineralogy, soil moisture content and pH (Bardgett et al. 2005; Fierer & Jackson 2006; Myers et al. 2001). However, comparative studies on the effect of specific edaphic variables on the composition of the rhizobiome are rare because of a lack of suitable study sites where the influence of different soil types on the same plant species in close proximity can be compared effectively.","PeriodicalId":48892,"journal":{"name":"Koedoe","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83064200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plant community structure and possible vegetation changes after drought on a granite catena in the Kruger National Park, South Africa","authors":"A. V. Aardt, D. Codron, Ettienne J. Theron, P. D. Preez","doi":"10.4102/koedoe.v62i2.1585","DOIUrl":"https://doi.org/10.4102/koedoe.v62i2.1585","url":null,"abstract":"The Earth’s environment is dominated by three great natural components, namely, climate, vegetation and soil. Climate is considered the most important factor influencing the distribution and composition of vegetation on a micro and sub-continental scale (Campbell et al. 2008; Furley 2010; Scholes 1997; Schulze 1997). Vegetation development is controlled largely by light, temperature and moisture (Bond, Midgley & Woorward 2003; Schulze 1997). Topography and the chemical and physical compositions of the soil also influence vegetation and, in conjunction with climate, are responsible for the intricate interactions that govern the worldwide distribution of vegetation (Campbell et al. 2008; Furley 2010; Scholes 1997). Understanding how these interactions regulate the ecology of plant communities is critical for characterising the impacts of global change on biodiversity at local and regional scales.","PeriodicalId":48892,"journal":{"name":"Koedoe","volume":"2 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82271786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biotic and abiotic connections on a granitic catena: Framework for multidisciplinary research","authors":"B. Janecke, J. Tol, I. Smit, A. V. Aardt, E. Riddell, M. Seaman, W. Swart, P. D. Preez, P. L. Roux","doi":"10.4102/koedoe.v62i2.1600","DOIUrl":"https://doi.org/10.4102/koedoe.v62i2.1600","url":null,"abstract":"The concept of savanna heterogeneity has been fundamental in how this has informed the management of the Kruger National Park (KNP), and has influenced, for example, how fire, artificial surface water and large herbivores are managed to maintain, mimic or, in some cases, restore inherent heterogeneity. For an overview of the concepts of heterogeneity in the savanna context on different levels from a fine to a broader scale, and how that has influenced thinking and management of the KNP, see Du Toit, Rogers and Biggs (ed. 2003) and Rogers (2003). ‘Heterogeneity’ is a broad term, but can comprise differences and interactions between soil types and properties, vegetation composition and structure, patchiness and patterns, sub-habitats, animal presence and so on. Local environmental gradients on a catenal scale create ecological patterns from the crest to the stream of the hillslope. Bottom-up drivers interact with top-down controls to give rise to these patterns. A multidisciplinary project was conducted to study the processes that govern functioning, structure and heterogeneity on a catena in a third-order catchment in the Southern Granite Supersite in the Kruger National Park. The project included abiotic components (e.g. groundwater-surface water interactions, soil chemical and physical properties) as well as biotic components (e.g. soil microbes, small aquatic organisms in ephemeral pools, plant communities, vegetation structure and mammal diversity). Each of these components was investigated in detail along the catenal gradient and reported on in separate articles in this special issue. The drought of 2015–2016 occurred during the sampling period of the study and information on the response of vegetation and mammals to the drought were included. In this article, a synthesis of findings from the separate components or disciplines is provided to highlight the interactive functioning and ecological patterns of the catena. These findings were then used to develop a framework for multidisciplinary studies in similar environments. The framework highlights the interactive relationships between various components of the ecosystem and the importance of a multidisciplinary approach.","PeriodicalId":48892,"journal":{"name":"Koedoe","volume":"54 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87889445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}