Browsing by Author "Cowling, Richard M."
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- ItemChallenges in invasive alien plant control in South Africa(Academy of Science of South Africa, 2012) Van Wilgen, Brian W.; Cowling, Richard M.; Marais, Christo; Esler, Karen J.; McConnachie, Matthew; Sharp, DebbieWorking for Water owes much to the community of fynbos ecologists who were instrumental in putting forward an argument to government for its initiation in 1996.2 The 33rd Annual Fynbos Forum (attended by over 250 delegates at Cape St. Francis on 17–19 July 2012) included a plenary workshop on the effectiveness of Working for Water, and discussions on ways for the scientific community to assist in the identification and implementation of improvements. This brief report outlines the issues discussed, including the problems faced by Working for Water, and possible ways for the scientific community to assist in addressing them.
- ItemExtinction risk and diversification are linked in a plant biodiversity hotspot(Public Library of Science, 2011-05) Davies, T. Jonathan; Smith, Gideon F.; Bellstedt, Dirk U.; Boatwright, James S.; Bytebier, Benny; Cowling, Richard M.; Forest, Felix; Harmon, Luke J.; Muasya, A. Muthama; Schrire, Brian D.; Steenkamp, Yolande; Van der Bank, Michelle; Savolainen, VincentIt is widely recognized that we are entering an extinction event on a scale approaching the mass extinctions seen in the fossil record. Present-day rates of extinction are estimated to be several orders of magnitude greater than background rates and are projected to increase further if current trends continue. In vertebrates, species traits, such as body size, fecundity, and geographic range, are important predictors of vulnerability. Although plants are the basis for life on Earth, our knowledge of plant extinctions and vulnerabilities is lagging. Here, we disentangle the underlying drivers of extinction risk in plants, focusing on the Cape of South Africa, a global biodiversity hotspot. By comparing Red List data for the British and South African floras, we demonstrate that the taxonomic distribution of extinction risk differs significantly between regions, inconsistent with a simple, trait-based model of extinction. Using a comprehensive phylogenetic tree for the Cape, we reveal a phylogenetic signal in the distribution of plant extinction risks but show that the most threatened species cluster within short branches at the tips of the phylogeny—opposite to trends in mammals. From analyzing the distribution of threatened species across 11 exemplar clades, we suggest that mode of speciation best explains the unusual phylogenetic structure of extinction risks in plants of the Cape. Our results demonstrate that explanations for elevated extinction risk in plants of the Cape flora differ dramatically from those recognized for vertebrates. In the Cape, extinction risk is higher for young and fast-evolving plant lineages and cannot be explained by correlations with simple biological traits. Critically, we find that the most vulnerable plant species are nonetheless marching towards extinction at a more rapid pace but, surprisingly, independently from anthropogenic effects. Our results have important implications for conservation priorities and cast doubts on the utility of current Red List criteria for plants in regions such as the Cape, where speciation has been rapid, if our aim is to maximize the preservation of the tree-of-life.
- ItemFire regimes in eastern coastal fynbos : imperatives and thresholds in managing for diversity(AOSIS Publishing, 2013) Kraaij, Tineke; Cowling, Richard M.; Van Wilgen, Brian W.Until recently, fire ecology was poorly understood in the eastern coastal region of the Cape Floral Kingdom (CFK), South Africa. Rainfall in the area is aseasonal and temperatures are milder than in the winter-rainfall and drier inland parts of the CFK, with implications for the management of fire regimes. We synthesised the findings of a research programme focused on informing ecologically sound management of fire in eastern coastal fynbos shrublands and explored potential east–west trends at the scales of study area and CFK in terms of fire return interval (FRI) and fire season. FRIs (8–26 years; 1980–2010) were comparable to those elsewhere in the CFK and appeared to be shorter in the eastern Tsitsikamma than in the western Outeniqua halves of the study area. Proteaceae juvenile periods (4–9 years) and post-fire recruitment success suggested that for biodiversity conservation purposes, FRIs should be ≥ 9 years in eastern coastal fynbos. Collectively, findings on the seasonality of actual fires and the seasonality of fire danger weather, lightning and post-fire proteoid recruitment suggested that fires in eastern coastal fynbos are not limited to any particular season. We articulated these findings into ecological thresholds pertaining to the different elements of the fire regime in eastern coastal fynbos, to guide adaptive management of fire in the Garden Route National Park and elsewhere in the region. Conservation implications: Wildfires are likely to remain dominant in eastern coastal fynbos, whilst large-scale implementation of prescribed burning is unattainable. Fires occurring in any season are not a reason for concern, although other constraints remain: the need for sufficient fire intensity, safety requirements, and integration of fire and invasive alien plant management.
- ItemKaroo research update : progress, gaps and threats(ASSAf, 2021-01-29) Hoffman, Michael T.; Cowling, Richard M.; Petersen, Hana; Walker, CherrylIt has been more than three decades since the conclusion of the Karoo Biome Project (KBP).1 At its height in the late 1980s, the KBP coordinated the efforts of nearly 100 research projects across a range of mainly ecological and agricultural disciplines. In this brief update we examine the research that has occurred in the Nama-Karoo and Succulent Karoo biomes since then and describe the relative contributions made by different disciplines to this body of knowledge. We also highlight efforts to synthesise knowledge across the disciplinary divides. Finally, we identify notable gaps in the research, especially considering the major land-use changes that are occurring across the Karoo. We conclude that new questions should be asked and that significantly greater collaboration between disciplines should be fostered in order to address the pressing challenges facing the Karoo more effectively. This necessitates a far more coordinated response than has been the case to date. Institutional leadership and additional funding will also be required to achieve this.
- ItemMainstreaming biodiversity : conservation for the twenty-first century(Frontiers Media, 2015-12-08) Redford, Kent H.; Huntley, Brian J.; Roe, Dilys; Hammond, Tom; Zimsky, Mark; Lovejoy, Thomas E.; Da Fonseca, Gustavo A. B.; Rodriguez, Carlos M.; Cowling, Richard M.Insufficient focused attention has been paid by the conservation community to conservation of biodiversity outside of protected areas. Biodiversity mainstreaming addresses this gap in global conservation practice by “embedding biodiversity considerations into policies, strategies and practices of key public and private actors that impact or rely on biodiversity, so that it is conserved, and sustainably used, both locally and globally” (Huntley and Redford, 2014). Biodiversity mainstreaming is designed to change those policies and practices that influence land uses outside of protected areas as well as to change economic and development decision-making by demonstrating the importance of conserving biodiversity for achieving development outcomes. The practice of mainstreaming is tied to implementation of the Convention on Biological Diversity and is practiced with billions of dollars of investment by development agencies, national government agencies, and the Global Environment Facility (GEF) and its implementing organizations as well as other donors. It is essential for the long-term survival of biodiversity inside and outside protected areas. However, it is virtually unheard of in the main conservation science field. This must change so as to bring careful documentation, analysis, monitoring, publishing, and improvement of practices—all things that conservation science should provide as partners to practitioners of biodiversity mainstreaming. The situation is ripe for informed coordination and consolidation and creation of a science-driven field of biodiversity mainstreaming.
- ItemVegetation responses to season of fire in an aseasonal, fire-prone fynbos shrubland(PeerJ, 2017-08-10) Kraaij, Tineke; Cowling, Richard M.; Van Wilgen, Brian W.; Rikhotso, Diba R.; Difford, MarkSeason of fire has marked effects on floristic composition in fire-prone Mediterranean- climate shrublands. In these winter-rainfall systems, summer-autumn fires lead to optimal recruitment of overstorey proteoid shrubs (non-sprouting, slow-maturing, serotinous Proteaceae) which are important to the conservation of floral diversity. We explored whether fire season has similar effects on early establishment of five proteoid species in the eastern coastal part of the Cape Floral Kingdom (South Africa) where rainfall occurs year-round and where weather conducive to fire and the actual incidence of fire are largely aseasonal. We surveyed recruitment success (ratio of post-fire recruits to pre-fire parents) of proteoids after fires in different seasons. We also planted proteoid seeds into exclosures, designed to prevent predation by small mammals and birds, in cleared (intended to simulate fire) fynbos shrublands at different sites in each of four seasons and monitored their germination and survival to one year post-planting (hereafter termed `recruitment'). Factors (in decreasing order of importance) affecting recruitment success in the post-fire surveys were species, pre-fire parent density, post-fire age of the vegetation at the time of assessment, and fire season, whereas rainfall (for six months post-fire) and fire return interval (>7 years) had little effect. In the seed-planting experiment, germination occurred during the cooler months and mostly within two months of planting, except for summer-plantings, which took 2 3 months longer to germinate. Although recruitment success differed significantly among planting seasons, sites and species, significant interactions occurred among the experimental factors. In both the post-fire surveys and seed planting experiment, recruitment success in relation to fire- or planting season varied greatly within and among species and sites. Results of these two datasets were furthermore inconsistent, suggesting that proteoid recruitment responses are not related to the season of fire. Germination appeared less rainfall-dependent than in winter-rainfall shrublands, suggesting that summer drought-avoiding dormancy is limited and has less influence on variation in recruitment success among fire seasons. The varied response of proteoid recruitment to fire season (or its simulation) implies that burning does not have to be restricted to particular seasons in eastern coastal fynbos, affording more flexibility for fire management than in shrublands associated with winter rainfall.