Browsing by Author "Foxcroft, L. C."

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    Developing thresholds of potential concern for invasive alien species : hypotheses and concepts
    (AOSIS, 2009) Foxcroft, L. C.
    The Kruger National Park (KNP) has developed and refined a system of management called 'strategic adaptive management' (SAM), which rests on the concept of 'threshold of potential concern' (TPC). TPCs represent end-points in a continuum of change. When thresholds are reached - at which point concerns of negative impacts on biodiversity are raised - management options are explicitly considered and implemented. This paper describes the TPCs developed for monitoring and managing invasive alien species (IAS). More importantly, however, it describes the conceptual understanding, principles and hypotheses adopted as the foundations for setting these TPCs. In accordance with adaptive management practices, the TPCs will be revised as the ecological and conceptual understanding of invasions grows and information is gained through research in the KNP and elsewhere. Conservation implication: In accepting that species and systems are variable, and that flux is inevitable and desirable, these TPCs developed for invasive alien species specifically, provide end points against which monitoring can be assessed. Once a threshold is reached, the cause of the threshold being exceeded is examined and management interventions recommended. © 2009. The Authors.
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    The development and application of strategic adaptive management within South African national parks
    (AOSIS, 2011) Roux, D. J.; Foxcroft, L. C.
    Adaptive management is an appealing approach to deal with inherent uncertainty in complex and interactive social-ecological systems (Holling 2001; Rogers 2003). In short, adaptive management is about learning-by-doing in a scientific way, adapting behaviour and overall direction as new information becomes available. It provides a structured way for improving our incomplete understanding through an iterative process of setting objectives, implementing policy decisions and evaluating the implications of their outcomes for future decision making.
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    Implementing invasive species management in an adaptive management framework
    (AOSIS, 2011) Foxcroft, L. C.; Mcgeoch, M.
    Adaptive management theory has attracted substantial interest in recent years, in natural resource management in general and also for invasive alien species management. However, whilst many theoretical and conceptual advances have been made, documented cases of practical applications are rare. Coupling invasive species management components with adaptive feedback processes is not without challenges, requiring a substantial change in the thinking and practice of all those involved. Drawing on a decade of experience in South African National Parks, we suggest an approach to implementing adaptive management for controlling invasive alien species. Whilst efforts have been made to advance components of the overall management strategy, the absence of a framework for decision making and feedback mechanisms, inflexibility in the system and shortcomings in the governance structure are all identified as barriers to learning and knowledge integration for the purposes of effective invasive alien species management. The framework provided here, encompassing documents, committees and processes, is aimed at addressing these shortcomings. © 2011.
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    Predicting incursion of plant invaders into Kruger National Park, South Africa : the interplay of general drivers and species-specific factors
    (PLOS, 2011-12) Jarosik, V.; Pysek, P.; Foxcroft, L. C.; Richardson, David M.; Rouget, M.; MacFadyen, S.
    Background: Overcoming boundaries is crucial for incursion of alien plant species and their successful naturalization and invasion within protected areas. Previous work showed that in Kruger National Park, South Africa, this process can be quantified and that factors determining the incursion of invasive species can be identified and predicted confidently. Here we explore the similarity between determinants of incursions identified by the general model based on a multispecies assemblage, and those identified by species-specific models. We analyzed the presence and absence of six invasive plant species in 1.061.5 km segments along the border of the park as a function of environmental characteristics from outside and inside the KNP boundary, using two data-mining techniques: classification trees and random forests. Principal Findings: The occurrence of Ageratum houstonianum, Chromolaena odorata, Xanthium strumarium, Argemone ochroleuca, Opuntia stricta and Lantana camara can be reliably predicted based on landscape characteristics identified by the general multispecies model, namely water runoff from surrounding watersheds and road density in a 10 km radius. The presence of main rivers and species-specific combinations of vegetation types are reliable predictors from inside the park. Conclusions: The predictors from the outside and inside of the park are complementary, and are approximately equally reliable for explaining the presence/absence of current invaders; those from the inside are, however, more reliable for predicting future invasions. Landscape characteristics determined as crucial predictors from outside the KNP serve as guidelines for management to enact proactive interventions to manipulate landscape features near the KNP to prevent further incursions. Predictors from the inside the KNP can be used reliably to identify high-risk areas to improve the costeffectiveness of management, to locate invasive plants and target them for eradication.
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    The status of Koedoe one year after changing to an online publication mode
    (AOSIS, 2009) Foxcroft, L. C.
    2008 represented the start of a new online era for Koedoe, which provided us with a number of challenges and opportunities. The challenges lay in developing an entirely new publication and information dissemination system containing a number of new processes. The opportunities however, allowed us to build on Koedoes' 50 year publication history. The main opportunity for Koedoe lies in using the open access publication route, where all our articles are freely available via the World Wide Web. Further, all back issues of the journal will be available as PDF downloads by March 2009, additional special interest sections were added (for example, essays and book reviews) and the marketing strategy was expanded to reach a wider audience.