Pub Date : 2020-10-29DOI: 10.4102/koedoe.v62i1.1629
Kevin M. Coldrey, J. Turpie
Climate change has the potential to have significant impacts on the global tourism industry through changes in accessibility and comfort levels, as well as geographic or seasonal changes to attractions (Rosselló-Nadal 2014; Scott, Gössling & Hall 2012). Global and regional studies based on climate indices and data suggest that there will be global shifts in tourism, with an improvement in conditions in many temperate areas and a deterioration in conditions in many subtropical and tropical areas (Bigano, Hamilton & Tol 2007; Rosselló & Santana 2012; Tol & Walsh 2012). Indications are that tourism may decline in much of the Global South. This is of particular concern, not only because tourism is a significant source of foreign exchange earnings in developing countries (Scott et al. 2012), but also because of the global importance of biodiversity conservation in these countries and the direct and indirect reliance of conservation on nature-based tourism. However, comparatively little empirical work has been done on nature-based or protected area tourism, particularly in developing countries.
气候变化有可能通过可达性和舒适度的变化，以及景点的地理或季节变化，对全球旅游业产生重大影响(Rosselló-Nadal 2014;Scott, Gössling & Hall 2012)。基于气候指数和数据的全球和区域研究表明，全球旅游业将发生变化，许多温带地区的条件将得到改善，而许多亚热带和热带地区的条件将恶化(Bigano, Hamilton & Tol 2007;Rosselló &桑塔纳2012;Tol & Walsh 2012)。有迹象表明，全球南方大部分地区的旅游业可能会下滑。这一点尤其令人担忧，不仅因为旅游业是发展中国家外汇收入的重要来源(Scott et al. 2012)，还因为这些国家生物多样性保护的全球重要性，以及保护对以自然为基础的旅游业的直接和间接依赖。然而，特别是在发展中国家，关于基于自然或保护区的旅游的实证工作相对较少。
{"title":"Potential impacts of changing climate on nature-based tourism: A case study of South Africa’s national parks","authors":"Kevin M. Coldrey, J. Turpie","doi":"10.4102/koedoe.v62i1.1629","DOIUrl":"https://doi.org/10.4102/koedoe.v62i1.1629","url":null,"abstract":"Climate change has the potential to have significant impacts on the global tourism industry through changes in accessibility and comfort levels, as well as geographic or seasonal changes to attractions (Rosselló-Nadal 2014; Scott, Gössling & Hall 2012). Global and regional studies based on climate indices and data suggest that there will be global shifts in tourism, with an improvement in conditions in many temperate areas and a deterioration in conditions in many subtropical and tropical areas (Bigano, Hamilton & Tol 2007; Rosselló & Santana 2012; Tol & Walsh 2012). Indications are that tourism may decline in much of the Global South. This is of particular concern, not only because tourism is a significant source of foreign exchange earnings in developing countries (Scott et al. 2012), but also because of the global importance of biodiversity conservation in these countries and the direct and indirect reliance of conservation on nature-based tourism. However, comparatively little empirical work has been done on nature-based or protected area tourism, particularly in developing countries.","PeriodicalId":48892,"journal":{"name":"Koedoe","volume":"35 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80975759","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}
Pub Date : 2020-10-29DOI: 10.4102/koedoe.v62i2.1639
W. Swart, M. Seaman, Pieter AL Le Roux, B. Janecke
{"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}
Pub Date : 2020-10-29DOI: 10.4102/koedoe.v62i2.1602
J. Tol, S. Julich, D. Bouwer, E. Riddell
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).
稀树草原目前正面临着全球范围内广泛的人口和农业水资源压力(Rockström et al. 2014)。因为我们现在正进入一个生态系统适应性管理的时代，在这个时代，状态变化阈值的信息是其持续管理的先决条件，因此有必要投资于理解维持这些系统的生物物理过程。在稀树草原景观中，土壤水分是降水和生态模式之间的直接联系(Weltzin et al. 2003)。树木和草的共同支配受土壤水分有效性的制约，土壤水分有效性是形成形态和功能的关键因素。因此，空间土壤水分动态是这些系统中气候、土壤和植被平衡的关键环节(Rodriguez-Iturbe et al. 1999)。由此产生的水文过程有助于形成这些半干旱系统的生物物理模板，控制着景观内沿连续体的水和其他资源的分布，这通常包括非线性关系和阈值触发响应的复合效应。鉴于这种复杂性，应该寻求新的跨学科方法来理解这种异质景观中的水文过程(Troch et al. 2008)。此外，鉴于强调景观尺度上的水文连通性，跨学科对成功的景观管理越来越有价值(Michaelides & Chappell 2009)。
{"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}
Pub Date : 2020-10-29DOI: 10.4102/koedoe.v62i2.1584
D. Bouwer, P. L. Roux, J. Tol
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).
土壤在水文流道的分配和水在景观中的停留期中起着一级控制作用。另一方面，水是土壤形成的主要因素，并留下了水分运动和储存的独特土壤形态特征。土壤和水之间的这种相互作用关系是一个相对较新的跨学科研究领域的基础，称为水文学(Lin 2010;Lin et al. 2006)。这一协同研究领域促进了一种更综合的方法来解决有关半干旱景观中可变水状况下水资源管理的复杂问题(Kutílek & Nielsen 2007;林2003;Lin et al. 2006b)。景观尺度的水文学研究通常包括水文循环的各个组成部分，并认识到地表和地下水在不同时空尺度上的密切关系(Van Tol & Lorentz 2018)。
{"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}
Pub Date : 2020-10-29DOI: 10.4102/koedoe.v62i2.1583
E. Riddell, J. Nel, J. V. van Tol, D. Fundisi, Faith Jumbi, Ashton Van Niekerk, S. Lorentz
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.
{"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}
Pub Date : 2020-10-29DOI: 10.4102/koedoe.v62i2.1640
Leslie R. Brown, Andri C. van Aardt, Beanelri B. Janecke
{"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}
Pub Date : 2020-10-29DOI: 10.4102/koedoe.v62i2.1597
M. Gryzenhout, E. Cason, M. Vermeulen, George A.E. Kloppers, Brooke Bailey, Soumya Ghosh
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).
{"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}
Pub Date : 2020-10-29DOI: 10.4102/koedoe.v62i2.1596
M. Vermeulen, E. Cason, W. Swart
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.
根际的特点是微生物活性高，以及一系列复杂和动态的物理、化学和生物相互作用，称为“根际效应”(Helliwell等人，2019;Hiltner 1904)。这些相互作用在植物营养中起着至关重要的作用(Raaijmakers et al. 2009;Sørensen 1997)和陆地生态系统的生态系统功能(Singh et al. 2004)。与根际相关的微生物(即根际微生物组或根瘤菌组)代表了微生物多样性的巨大储存库，包括真菌、细菌、线虫、原生动物、藻类、病毒和节肢动物(Berg & Smalla 2009;Bonkowski et al. 2000;Bonkowski, Villenave & Griffiths, 2009;Bulgarelli et al. 2013)。植物物种通过分泌根系分泌物来吸引或排斥周围块状土壤中的特定细菌，从而主动决定其根瘤菌群的组成(Berg & Smalla 2009;Doornbos, Van Loon & Bakker 2012)。因此，根瘤菌群的组成是由紧邻的大块土壤的许多土壤变量决定的，如土壤矿物学、土壤水分含量和pH值(Bardgett et al. 2005;Fierer & Jackson 2006;Myers et al. 2001)。然而，关于特定土壤变量对根瘤菌群组成影响的比较研究很少，因为缺乏合适的研究地点，可以有效地比较不同土壤类型对近距离同一植物物种的影响。
{"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}
Pub Date : 2020-10-29DOI: 10.4102/koedoe.v62i2.1585
A. V. Aardt, D. Codron, Ettienne J. Theron, P. D. Preez
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.
{"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}
Pub Date : 2020-10-29DOI: 10.4102/koedoe.v62i2.1600
B. Janecke, J. Tol, I. Smit, A. V. Aardt, E. Riddell, M. Seaman, W. Swart, P. D. Preez, P. L. Roux
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.
{"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}
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