ORCID Profile
0000-0002-8685-9603
Current Organisations
Hogeschool Van Hall Larenstein - Velp
,
University of Johannesburg
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Publications
Human activities, propagule pressure and alien plants in the sub-Antarctic: tests of generalities and evidence in support of management
Publisher: Elsevier BV
Date: 05-2013
A global indicator for biological invasion
Publisher: Wiley
Date: 13-11-2006
DOI: 10.1111/J.1523-1739.2006.00579.X
Abstract: "Trends in invasive alien species" is one of only two indicators of threat to bio ersity that form part of the Convention on Biological Diversity's (CBD) framework for monitoring progress toward its "2010 target" (i.e., the commitment to achieve by 2010 a significant reduction in the current rate of bio ersity loss). To date, however, there is no fully developed indicator for invasive alien species (IAS) that combines trends, derived from a standard set of methods, across species groups, ecosystems, and regions. Here we provide a rationale for the form and characteristics of an indicator of trends in IAS that will meet the 2010 framework goal and targets for this indicator. We suggest single and composite indicators that include problem-status and management-status measures that are designed to be flexible, readily disaggregated, and as far as possible draw on existing data. The single indicators at national and global scales are number of IAS and numbers of operational management plans for IAS. Global trends in IAS are measured as the progress of nations toward the targets of stabilizing IAS numbers and the implementation of IAS management plans. The proposed global indicator thus represents a minimum information set that most directly addresses the indicator objective and simultaneously aims to maximize national participation. This global indicator now requires testing to assess its accuracy, sensitivity, and tractability. Although it may not be possible to achieve the desired objective for a global indicator of biological invasion by 2010 as comprehensively as desired, it seems possible to obtain trend estimates for a component of the taxa, ecosystems, and regions involved. Importantly, current indicator development initiatives will also contribute to developing the mechanisms necessary for monitoring global trends in IAS beyond 2010.
Climate change and elevational diversity capacity: do weedy species take up the slack?
Publisher: The Royal Society
Date: 23-02-2013
Abstract: Climate change leads to species range shifts and consequently to changes in ersity. For many systems, increases in ersity capacity have been forecast, with spare capacity to be taken up by a pool of weedy species moved around by humans. Few tests of this hypothesis have been undertaken, and in many temperate systems, climate change impacts may be confounded by simultaneous increases in human-related disturbance, which also promote weedy species. Areas to which weedy species are being introduced, but with little human disturbance, are therefore ideal for testing the idea. We make predictions about how such ersity capacity increases play out across elevational gradients in non-water-limited systems. Then, using modern and historical data on the elevational range of indigenous and naturalized alien vascular plant species from the relatively undisturbed sub-Antarctic Marion Island, we show that alien species have contributed significantly to filling available ersity capacity and that increases in energy availability rather than disturbance are the probable underlying cause.
Are road verges corridors for weed invasion? Insights from the fine‐scale spatial genetic structure of R aphanus raphanistrum
Publisher: Wiley
Date: 21-06-2013
DOI: 10.1111/WRE.12033
Patterns of weed invasion: evidence from the spatial genetic structure of Raphanus raphanistrum
Publisher: Springer Science and Business Media LLC
Date: 25-04-2013
Road verges as invasion corridors? A spatial hierarchical test in an arid ecosystem
Publisher: Springer Science and Business Media LLC
Date: 14-02-2008
Human activity strongly influences genetic dynamics of the most widespread invasive plant in the sub‐Antarctic
Publisher: Wiley
Date: 07-07-2022
DOI: 10.1111/MEC.16045
Abstract: The link between the successful establishment of alien species and propagule pressure is well‐documented. Less known is how humans influence the post‐introduction dynamics of invasive alien populations. The latter requires studying parallel invasions by the same species in habitats that are differently impacted by humans. We analysed microsatellite and genome size variation, and then compared the genetic ersity and structure of invasive Poa annua L. on two sub‐Antarctic islands: human‐occupied Marion Island and unoccupied Prince Edward Island. We also carried out niche modelling to map the potential distribution of the species on both islands. We found high levels of genetic ersity and evidence for extensive admixture between genetically distinct lineages of P . annua on Marion Island. By contrast, the Prince Edward Island populations showed low genetic ersity, no apparent admixture, and had smaller genomes. On both islands, high genetic ersity was apparent at human landing sites, and on Marion Island, also around human settlements, suggesting that these areas received multiple introductions and/or acted as initial introduction sites and secondary sources (bridgeheads) for invasive populations. More than 70 years of continuous human activity associated with a meteorological station on Marion Island led to a distribution of this species around human settlements and along footpaths, which facilitates ongoing gene flow among geographically separated populations. By contrast, this was not the case for Prince Edward Island, where P . annua populations showed high genetic structure. The high levels of genetic variation and admixture in P . annua facilitated by human activity, coupled with high habitat suitability on both islands, suggest that P . annua is likely to increase its distribution and abundance in the future.
Related Organisations
Related Funding Activities
No related grants have been discovered for Jesse Kalwij.