African Journal of Range & Forage Science最新文献

{"title":"Drought as a driver of vegetation change in Succulent Karoo rangelands, South Africa","authors":"S. Milton, H. Petersen, G. Nampa, H. van der Merwe, JR Henschel","doi":"10.2989/10220119.2021.1992501","DOIUrl":"https://doi.org/10.2989/10220119.2021.1992501","url":null,"abstract":"We document changes in rangeland during a prolonged drought in the arid Karoo. Rangeland in this arid region is species-rich and dominated by a mixture of long-lived succulent and non-succulent shrubs. Ranching has led to the domination of vegetation by less palatable species, and resting does little to restore diversity because most species are long-lived. Between 2015 and 2020, a combination of rising temperatures and low rainfall reduced vegetation cover and grazing potential throughout the Karoo. Mortality varied among species, habitat and with predrought rangeland condition, but appeared independent of size class. Growth form was not a good predictor of drought survival, although vegetation dominated by non-succulent shrub species before the drought was dominated by a succulent shrub species toward the end of the drought. Dieback was greater on deep soil than in drainage lines and on stony rises. Historically degraded landscapes lost relatively more vegetation cover and grazing capacity than areas protected from grazing. By reducing dominant, long-lived, non-forage shrub species, drought appears to be changing the composition of the vegetation to a state that may have higher grazing potential, particularly if livestock numbers are reduced and reseeding is carried out during the recovery period.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"11 1","pages":"181 - 195"},"PeriodicalIF":1.4,"publicationDate":"2022-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87721899","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":"Effects of short-duration kraaling depend on initial conditions in a mesic grassland","authors":"H. Hawkins, N. Mgwali, S. Vetter","doi":"10.2989/10220119.2021.2012716","DOIUrl":"https://doi.org/10.2989/10220119.2021.2012716","url":null,"abstract":"Short-duration overnight kraaling has been suggested as a tool for restoring degraded rangelands. However, the response of different plant functional types and communities to such intense livestock impact may vary depending on local context. We thus examined the effects of short-duration overnight kraaling on soil and vegetation characteristics in a mesic montane grassland in South Africa using paired kraal and control sites, as part of a low intensity grazing approach. Kraaling increased soil P and S, as well as soil organic matter (except when initial values were over 12%). The effect of kraaling on vegetation was strongly dependent on initial condition. Basal cover of grasses and forbs increased by approximately 50 and 15%, respectively, if sites had very low initial basal cover, but decreased by up to 15% if initial values were over 50% and 10%, respectively. Kraaling always decreased herbaceous biomass, but especially when initial values were over 2 000 kg ha−1. In mesic grasslands, short-duration overnight kraaling is promising as a tool for rehabilitating degraded sites or fertilizing abandoned cropland, but should be avoided where the grass sward is intact. We recommend that the suitability of kraaling be evaluated per vegetation type and local context.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"4 1","pages":"196 - 205"},"PeriodicalIF":1.4,"publicationDate":"2022-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75268741","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":"Fieldwork Ready: An Introductory Guide to Field Research for Agriculture, Environment and Soil Scientists","authors":"M. Tedder","doi":"10.2989/10220119.2022.2032344","DOIUrl":"https://doi.org/10.2989/10220119.2022.2032344","url":null,"abstract":"","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"13 1","pages":"349 - 350"},"PeriodicalIF":1.4,"publicationDate":"2022-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74082613","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":"Tipping the scales: how fire controls the balance among functional groups in Angolan grasslands","authors":"Paulina Meller, Raquel Frazão, F. Lages, N. Jürgens, M. Finckh","doi":"10.2989/10220119.2021.2012822","DOIUrl":"https://doi.org/10.2989/10220119.2021.2012822","url":null,"abstract":"Fire plays an important role in the ecology of tropical grasslands globally. However, detailed studies comparing the response of plant functional groups to fire seasonality, and thus phenological timing, are scarce from humid Afrotropical grasslands. Such information, however, is crucial for understanding what keeps the grasslands open and for enabling evidence-based management, and conservation. We initiated an experiment in frost- and fire-prone Angolan geoxyle grasslands in 2017, investigating the effect of different timing of fires on cover and diversity of trees, grasses, geoxyles and herbs. We installed permanent, randomised plots with fire exclusion, annual early and late dry-season burning, representing the local burning practices. Functional plant groups reacted differently to the treatments, becoming apparent at species level and their performance metrics. After three years, grass species benefitted from late and no burning, and herbs from late burning, whereas geoxyles thrived under early burning. Tree growth was suppressed under late burning, and did not increase with fire exclusion. Species richness and diversity was higher in burnt than in unburnt plots. Seasonal timing of fire tips the scales between geoxyles and grasses. The extraordinary plant diversity of Angolan geoxyle grasslands is a result of pyrodiversity and frost, keeping the grasslands open even in absence of fire.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"7 1","pages":"56 - 69"},"PeriodicalIF":1.4,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87854140","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":"High-intensity fire experiments to manage shrub encroachment: lessons learned in South Africa and the United States","authors":"R. Scholtz, Victoria M. Donovan, T. Strydom, C. Wonkka, U. Kreuter, W. E. Rogers, C. Taylor, I. Smit, N. Govender, W. Trollope, Dillon T. Fogarty, D. Twidwell","doi":"10.2989/10220119.2021.2008004","DOIUrl":"https://doi.org/10.2989/10220119.2021.2008004","url":null,"abstract":"Human alteration of fire regimes is a hallmark of the Anthropocene; yet few studies have fully explored the implications of utilizing high-intensity fires in grasslands and savannas to manage shrub encroachment. Decades of fire research in South Africa inspired a unique convergence of high-intensity fire experiments in the USA. In the Great Plains of North America, high-intensity fire trials were designed to remove traditional investigator constraints that minimised variability in fire intensity and to explore woody mortality thresholds across a broader suite of experimental conditions. At the same time, studies in the Kruger National Park, South Africa, similarly investigated high-intensity fires to examine previously unstudied relationships between high-intensity fires and woody encroachment. These scientific pursuits have contributed to theoretical advances in our understanding of fire-vegetation dynamics. In this paper, we synthesise these high-intensity fire experiments, the empirical evidence emerging from them and their importance for managing grassland and savanna ecosystems, and the lessons learned and challenges ahead to maintaining critical ranges of variation in fire regimes during the Anthropocene.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"14 1","pages":"148 - 159"},"PeriodicalIF":1.4,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90773363","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":"Lessons from a century of evidence-based fire management in grassy ecosystems","authors":"N. Govender, Carla Staver, S. Archibald, C. Wigley-Coetsee, T. Strydom, Glynis Humphrey, Duncan Kimuyu","doi":"10.2989/10220119.2022.2035489","DOIUrl":"https://doi.org/10.2989/10220119.2022.2035489","url":null,"abstract":"Since prehistory, fire has been influential as an ecosystem process and has been used by people as a tool to support livelihoods and maintain landscapes worldwide. This is especially true in grassy ecosystems, where landscapes and ecological systems are fire-adapted and fire-dependent and where, even today, people are reliant on fire to manage resources (e.g. grazing areas and important food plants). Currently, global attitudes towards fire and the use thereof are shaped by the impacts of fire in forests, resulting in flawed negative perspectives of the impacts and role of fire in grasslands. The environment in which we manage fire is also changing, climatically, politically, socially, and economically, at scales ranging from local to regional to global, with the potential to alter essential fire regimes that support biodiversity, ecosystem services, and people’s livelihoods. Understanding and managing fire to support both the social and ecological dynamics presents a formidable challenge. In Southern africa, the first formal scientific investigations of fire started in the early 1900s. although learning was common practice among traditional land managers, prevailing perceptions of fire in grassy ecosystems among European colonists and scientists were negative. Ecologists from this era (e.g. John William bews and John fV Philips) questioned prevailing negative attitudes, calling for more empirical and experimental investigations into fire impacts and behaviour. These efforts helped grow generations of fire ecologists, foster interactions among scientists, managers, and local communities, and raised important questions about whether the scientific approach complements or undermines indigenous knowledge and practices. One hundred years after the first scientific studies on fire impacts in southern africa were published, it is time to both celebrate and critically assess our current understanding and progress. Information from fire experiments offer a strong foundation for evidence-based fire management, with increasing emphasis on incorporating indigenous and traditional fire management practices that have been shown to reduce fire risk and carbon emissions and increase fire safety, while also promoting fire-dependent ecosystem processes and services. In this Special Issue, we include diverse perspectives that examine the evidence from ecological and social disciplines on fire management in grassy ecosystems across the world. More than a century of fire experiments and applied fire management and suppression, together with modern technological advances in fire detection, mappings and monitoring, offer a strong foundation for evidence-based fire management.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"62 3 1","pages":"v - vii"},"PeriodicalIF":1.4,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86393008","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":"Too much, too late: fires and reactive wildfire management in northern Botswana’s forests and woodland savannas","authors":"L. Cassidy, JS Perkins, J. Bradley","doi":"10.2989/10220119.2022.2033833","DOIUrl":"https://doi.org/10.2989/10220119.2022.2033833","url":null,"abstract":"Across much of southern Africa’s savanna wildernesses, wildfires burn unchecked. This is particularly true in the woodland savannas of northern Botswana, where wildfires originate outside of management activities, and are left to burn uncontrolled, because of limited resources and remoteness. There is concern that severe annual wildfires are resulting in the ‘savannisation’ of large tracts of wooded land across forest reserves, protected areas and surrounding wilderness areas. Because the current fire regime is unknown, management interventions are hard to introduce. We examine the recent 20-year (2001–2020) fire history in northern Botswana using MODIS satellitederived fire products to reveal fire frequency and seasonality. Six wildfire hotspots are identified for exploration of fire frequency and possible origins. Annual fire frequencies are far higher than would be expected without anthropogenic ignition. Extensive areas in some hotspots are shown to have burned between 14 and 16 out of the 20-year period. Fires peak in September, several weeks before the onset of the rainy season and associated lightning strikes, and when the fuel load is at its maximum and conditions at their driest. Adaptive fire management practices, such as those being followed in neighbouring South Africa and elsewhere should inform Botswana’s fire management policies.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"31 1","pages":"160 - 174"},"PeriodicalIF":1.4,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81719908","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 Winston Smuts Watts Trollope – a firebrand and visionary in fire research","authors":"N. Govender, S. Archibald, S. Vetter, C. Wigley-Coetsee","doi":"10.2989/10220119.2021.2017132","DOIUrl":"https://doi.org/10.2989/10220119.2021.2017132","url":null,"abstract":"","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"317 1","pages":"viii - x"},"PeriodicalIF":1.4,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74814601","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":"Woody cover change in relation to fire history and land-use in the savanna-woodlands of north-east Namibia (1996–2019)","authors":"Glynis Humphrey, Conor Eastment, L. Gillson, M. Timm Hoffman","doi":"10.2989/10220119.2021.2005145","DOIUrl":"https://doi.org/10.2989/10220119.2021.2005145","url":null,"abstract":"Vegetation cover estimates for trees, shrub-grass mosaics, and grassland and bare ground, were quantified in the savanna-woodland of Bwabwata National Park, north-east Namibia. Changes in woody cover were analysed using repeat photographs in combination with aerial photographs and recent satellite imagery taken between 1996 and 2019. Cover estimates for each vegetation type were obtained using object-based classification techniques and a non-parametric random forest classifier algorithm in eCognition Trimble software. Results show that over the two decades under investigation (1996–2019), trees declined (−10.6%), and the shrub-grass mosaic vegetation type increased (8.1%) across the park. The largest decline in trees occurred in the western land use areas (−36%), which also experienced the greatest increase in the shrub-grass mosaic (17%), when compared with areas in the east (11%). Variation of woody cover estimates is attributed to different seasonal fire management practices in the east versus the west of the park. The fire history (2000–2018) revealed that late dry season fires were frequent in the west, whereas in the east, early dry season fires were frequent. The stages of encroachment recorded in this study have consequences for biodiversity, people’s livelihoods, and tourism.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"10 1","pages":"96 - 106"},"PeriodicalIF":1.4,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74419550","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":"Intentions behind common and risky fires in south-eastern Tanzania","authors":"Ellie Wood, Mercy Mgaya, Christopher Andrews, K. Schreckenberg, J. Fisher, I. Grundy, C. Ryan","doi":"10.2989/10220119.2021.2000026","DOIUrl":"https://doi.org/10.2989/10220119.2021.2000026","url":null,"abstract":"Human-set fires are a crucial component of African savannas, affecting ecosystem structure, carbon emissions, local hazards and livelihoods. Yet, most fire research in these ecosystems focuses on the fire ecology of protected areas. Research exploring fire regimes in inhabited landscapes remains limited, undermining opportunities for culturally and environmentally sustainable fire management. To address this gap, we used interviews in Tanzanian farming communities and remote sensing to identify intentions behind fire use and the perceived relative frequency and riskiness of fires set for different purposes. We found that the most common ignitions were intentional and important to livelihoods. Burning was adaptive, responsive to environmental conditions, and optimised for the intended outcome with the perceived riskiest fires intentionally spreading uncontrolled. Remote sensing showed that most of the total burned area was accounted for by fires during the late dry season when people burned for activities, such as field preparation, and when environmental conditions encouraged fire spread. Our findings offer an insight into fire regimes in inhabited landscapes, by exploring how intentions shape the fire regime at the landscape scale. We discuss how understanding these intentions and local priorities, including adaptive uses of fire, is key to sustainable fire management outside protected areas.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"384 1","pages":"124 - 135"},"PeriodicalIF":1.4,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73791903","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}