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Thesis (MSc )--Stellenbosch University, 2010. / ENGLISH ABSTRACT: The patterns of spread of non-indigenous species and the factors influencing their distribution have been studied infrequently on Southern Ocean Islands, where the prevention and control of biological invasions is a priority for conservation management. Owing to its remoteness and relatively small size, sub-Antarctic Marion Island provides an ideal opportunity to investigate the patterns of spread of invasive species and the factors likely influencing the distribution of alien species. Therefore, this study provides a spatially explicit documentation of the alien and invasive vascular plant species on Marion Island, the change in their distribution patterns through time, an assessment of the correlates of the current distributions, documentation of species rich areas, and provides recommendations for control based on these data and life history data available for each species. To ensure comprehensive coverage for the current estimate of distributions, a combination of a systematic (spatially explicit) survey and an ad hoc data collection method was used to examine the abundance and occupancy of each alien plant species across the island. The spatially explicit survey was used to identify sampling sites on a ½ minute by ½ minute scale (926 m × 926 m) which resulted in 348 sites across the island, whereas 2356 additional presence records were added during the ad hoc sampling. The residence time of each species was also estimated from the first records reported in various literature. While it has been documented in many studies that residence time is an important factor explaining species distribution, this study showed that distribution of alien species on Marion Island is not explained by residence time. The alien plant species on Marion Island differ markedly in their occupancy, distribution and rate of expansion. Agrostis stolonifera, Cerastium fontanum, Poa annua and Sagina procumbens are all expanding their ranges, whereas the range of Stellaria media appears to be contracting. Cerastium fontanum is the most widespread species on Marion Island while Sagina procumbens is the most abundant (number of records) and most rapidly expanding species on both Marion and Prince Edward Islands. Generalized linear models demonstrated that altitude, distance to human disturbed sites, and nearest neighbour presence are all significant and often strong correlates of spatial variation in alien vascular plant species richness and individual species presences on Marion Island. In particular, alien species richness on Marion Island declines sharply with increasing elevation, and that the distribution of the most widespread species is spatially aggregated. The surroundings of the Meteorological station and Mixed Pickle hut exhibit high richness and a high likelihood of the presence of individual species. None of the models developed for this study resulted in habitat type being significant explanatory variable for the distribution of any of the alien plant species, although from the records alone it is clear that the salt spray vegetation type is avoided. Together with assessments of the life history of the species, the current distribution data suggest that few alien plant species can be easily eradicated. Most are already too widespread already for cost effective eradication. Moreover, given the current rate of spread of Agrostis stolonifera, Cerastium fontanum, Poa annua and Sagina procumbens, and their apparent lack of habitat preference, it seems likely that within the next few decades many lowland habitats will be dominated by these species. By contrast, Rumex acestosella, Agrostis gigantea, Agropyron repens, Juncus effusus, Luzula cf. multiflora and the newly established shrub species should be the subject of control or eradication efforts. This thesis provides comprehensive baseline data on alien vascular plant distributions as a benchmark for future assessments. / AFRIKAANSE OPSOMMING: Die verspreidingspatrone van uitheemse spesies en die faktore wat hulle verspreiding beïnvloed is selde op Suidelike Oseaan Eilande bestudeer, waar die voorkoming en beheer van biologiese indringing ‘n prioriteit is vir bewaringsbestuur. Te danke aan sy afgeleëndheid en relatiewe klein grootte, voorsien sub-Antarktiese Marion Eiland ‘n ideale geleentheid om die patrone van verspreiding van indringer spesies en die faktore wat moontlik die verspreiding van uitheemse spesies beïnvloed te ondersoek. Daarom voorsien hierdie studie ‘n ruimtelik eksplisiete dokumentering van die uitheemse en indringer vaatplant spesies op Marion Eiland, die verandering in hulle verspreidingspatrone oor tyd, ‘n bepaling van die korrelasies van die huidige verspreidings, dokumentering van spesiesryke areas, en voorsien aanbevelings vir beheer gebasseer op hierdie data en die lewensloopdata beskikbaar vir elke spesie. Om omvattende dekking vir die huidige skatting van vespreidings te verseker, is ‘n kombinasie van sistematiese en ad hoc metodes gebruik om die talrykheid en besetting van elke uitheemse spesie oor die eiland te ondersoek. Die ruimtelik eksplisiete opname is gebruik om moniteringsplotte op ‘n ½ minuut by ½ minuut skaal (926 m × 926 m), met die resultaat van 348 plotte oor die eiland, terwyl 2356 addisionele voorkomsrekords bygevoeg is tydens die ad hoc versameling. Die verblyftyd van elke spesie is ook beraam vanaf die eerste rekords in die literatuur. Terwyl dit aangeteken is dat verblyftyd ‘n belangrike faktor is om spesie verspreiding te verduidelik, wys hierdie studie dat verspreiding van uitheemse spesies op Marion Eiland nie verduidelik word deur verblyftyd nie. Die uitheemse spesies op Marion Eiland verskil aansienlik in hulle besetting, verspreiding en tempo van uitbreiding. Agrostis stolonifera, Cerastium fontanum, Poa annua en Sagina procumbens brei almal hulle areas uit, terwyl die area van Stellaria media bleik te krimp. Cerastium fontanum is die mees wydverspreide spesie op Marion Eiland, terwyl Sagina procumbens die oorvloedigste (aantal rekords) en die vinnigste uitbreidende spesie is op beide Marion en Prince Edward Eiland. Veralgemeende lineêre modelle het aangetoon dat hoogte, afstand na menslike versteurde plotte, en naaste buurman teenwoordigheid almal betekenisvol is en gereeld sterk korreleer met ruimtelike variasie in uitheemse vaatplant spesierykheid en individuele spesie voorkoms op Marion Eiland. Uitheemse spesierykheid op Marion Eiland neem in besonder sterk af met ‘n toename in hoogte en die verspreiding van die mees wyduitgebreide spesies is ruimtelik saamgesteld. Die omgewing om die Weerstasie en Mixed Pickle hut toon hoë rykheid en ‘n hoë waarskynlikheid van die voorkoms van individuele spesies. Nie een van die modelle wat vir hierdie studie ontwikkel is toon ‘n belangrikheid in habitat tipe as ‘n verduidelikbare veranderlike vir die verspreiding van enige van die uitheemse plant spesies nie, alhoewel vanuit die rekords alleen is dit duidelik dat soutsproei plantegroei nie verkies word nie. Tesame met ondersoeke oor die lewensloop van die spesies, stel die huidige verspreidingsdata voor dat min uitheemse plant spesies maklik uitgeroei kan word. Die meeste is eenvoudig te wydverspreid vir koste effektiewe uitroeiing. Voorts, gegewe die huidige tempo van uitbreiding van Agrostis stolonifera, Cerastium fontanum, Poa annua en Sagina procumbens en hulle skynbare gebrek aan habitat voorkeur, is dit hoogs waarskynlik dat baie van die laerliggende habitatte binne die volgende paar dekades gedomineer sal word deur hierdie spesies. In teenstelling, Rumex acestosella, Agrostis gigantea, Agropyron repens, Juncus effusus, Luzula cf. multiflora en die nuutgevestigde struik spesie moet die fokus wees van beheer/uitroeiing pogings. Hierdie tesis voorsien omvattende basislyn data oor uitheemse vaatplantverspreidings as ‘n standaard vir toekomstige ondersoeke. / This project was funded by the South African National Antarctic Programme of the National Research Foundation (NRF – SANAP). Additional funding was provided by The Prince Edward Islands book fund.

Diploma thesis deals with alien species, primarily invasive species. Only in Europe there are 10 822 alien species, of which 10-15% could have a negative economic or ecological impact. Thesis highlights the threat alien species pose to the original species, biodiversity and human health, and necessity of cooperation in resolving this issue. The author gives their characteristics and provides an overview of legislation in the field of international, European and Czech law.

The change in total evaporation through alteration of vegetative cover is a major influence on catchment hydrology. The transformation of grassland and scrub habitats to commercial tree plantations, as well as the uncontrolled spread of invasive alien plants (lAPs) to ecologically sensitive systems, riparian zones in particular, are a threat to biodiversity and integrity of natural systems. Furthermore, critical low flow periods are of particular concern to water managers and local communities, as well as the associated impacts of potentially compromised water resources for rural livelihoods. The Working for Water (WfW) programme was implemented in 1995 by the Department of Water Affairs and Forestry and its main goals are to remove lAPs in order to improve water supply while at the same time providing employment to marginalised communities. In this study, the hydrological response to lAPs in the Upper Blyde River catchment is assessed. This is done by developing a classification structure for lAPs as a land use using detailed mapping available from WfW for use in a hydrological model, and then configuring and running the ACRU hydrological model for the Upper Blyde River catchment in Mpumalanga. In the classification, lAPs are represented as spatially explicit land use units in the ACRU model according to the type of habitat they invade, viz. riparian or non-riparian; as well as by type of plant, i.e. tree or shrub; and their area and density. The results obtained from simulating catchment hydrological responses using the ACRU model indicate that riparian lAPs have a great er impact on streamflow than do landscape invasions alone, specifically during periods of low flow. An increase in streamflow after removing lAPs from riparian and non-riparian habitats is a consistent outcome at both subcatchment and catchment scales. Using a spatially explicit method in order to model the hydrological response of different types of lAPs for different density classes in both riparian and non-riparian habitats is found to be a useful technique in determining the degree to which lAPs influence catchment streamflow. Recommendations for future research include focussing hydrological assessments of lAPs on critical flow periods and their impacts on water quality; investigation into the water use of invasive and indigenous vegetation for more accurate estimates from modelling exercises; and finally, applying the classification system for lAPs with other land use sensitive hydrological models for validation, and their wider application by incorporating methodologies into guidelines for use by WfW at national and provincial level. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.

This study investigates the economic impact of the ARC PPRI Weeds Research Division. The Division researches appropriate methods of biological control for invasive alien plants (IAPs). These plants pose an increasing threat to environmental integrity and ecosystem service provision impacting on economic potential. Since the work of the Division is considered a public good, a predominantly descriptive approach has been adopted for the valuation process. A combination of quantitative cost analysis and a qualitative study of the impacts of research and invasive alien plants is used to deal with the challenges associated with non-market valuation. The study found that investment into the Weeds Division is a valuable activity that supports the long-term growth potential of the South African economy. The role of a well-functioning environment is highlighted as an essential base for the creation of sustained growth opportunities in any society. It was determined that investment into the Division should be increased into the future to support efficient spending of scarce state funds. Biological control research was found to provide strategic future growth potential, creating opportunities for the development of a competitive advantage in the biotechnology and environmental management sectors. The study adds to the increasing move towards a more holistic view of economic valuation, taking factors other than pure finance and econometrics into consideration. This is an important shift in prevailing economic thought, as a realisation is reached that a single, or even triple, bottom line is an outdated and insufficient decision making basis.

Thesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008. / This thesis examines the role of agricultural activity in the process of invasion of west coast renosterveld fragments by annual alien grass species. This highly endangered vegetation type has less than 5% remaining, it is vital to understand the mechanisms allowing invasion of annual alien grasses in order to effectively prevent the loss of the many rare and endemic species found in west coast renosterveld. This study was divided into three major components. Firstly the distribution of indigenous and alien plant species in relation to fence lines, separating active agricultural fields from untransformed vegetation, was described. Regression analysis was used to test for relationships between distances from agricultural fields and soil physical and chemical characteristics in natural vegetation. Cover by annual alien invasive grasses in untransformed vegetation decreased significantly with distance away from agricultural land. Secondly alien and indigenous grass seed banks were sampled along the transects, at the same sites, in order to establish whether the seed banks correlated with above ground cover. Results varied among sites and seed banks were correlated with the vegetation cover at only one site. It appears that there are a multitude of factors determining the distribution of annual alien grass cover. Thirdly a greenhouse experiment established the role that nitrogen plays in the success of the alien grass Avena fatua. This species was grown in competition with three indigenous species, an annual forb (Dimorphotheca pluvialis), a geophyte (Oxalis purpurea) and an indigenous perennial grass (Tribolium uniolae) at three levels of soil nitrogen. The geophyte was largely unaffected, while growth of the annual and indigenous perennial grasses was negatively affected by competition with A. fatua. Nitrogen did not seem to affect competitive interactions. Management of these renosterveld patches, in order to conserve them effectively, will require a multi-faceted approach, including prevention of further invasion and removal of invasive grasses already present.

Thesis (DSc)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: No abstract available / AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar

Biological diversity is an essential prerequisite for life on earth and for the function of its ecosystems. Without biological diversity the ecosystems will eventually collapse, and it is thus necessary to maintain a healthy level of variation at ecological-, species- and genetic- level. Invasive alien species (IAS) are now recognized as the second highest threat to biological diversity. As a result, new legislation aiming to counteract the increasing issues with IAS are introduced e.g. in the EU. The purpose of this essay is to evaluate the function and importance of the precautionary principle regarding the control of IAS, using legal analysis. The legal analysis is complemented by an analysis of other scientific sources e.g. in order to describe biological diversity in general as well as the real and potential the ecosystem-consequences of the introduction of species. EU environmental law is based on the precautionary principle and so is thus the newly established IAS Regulation. The IAS Regulation requires an extensive riskassessment before a species will be encompassed by the regulation. The risk-assessment process does however not entirely correspond with the (strong version of the) precautionary principle, as actions in accordance with this principle requires an assumed risk, which must not necessarily be scientifically established. This results in a discrepancy between the legal definition and the actual definition of an IAS; species which have undergone the risk-assessment process can obtain the status of IAS (legally) whilst others, which has not yet been assessed or do not fulfil all criteria, do not have this status and are thus not covered by the legislation. There are 12 000 alien species within the EU, of which 1800 are considered invasive. However, only 49 different species are currently covered by the IAS-regulation. This cannot be considered to be in keeping with the (strong version of the) precautionary principle. / Biologisk mångfald är en förutsättning för liv på jorden och ekosystem behöver en variation av arter likväl som gener. Invasiva främmande arter (IAS) har erkänts som ett av de största hoten mot den biologiska mångfalden, vilket har resulterat i ny lagstiftning inom EU. Syftet med den här uppsatsen är att fastställa vilken roll försiktighetsprincipen spelar vid regler som omfattar IAS; i allmänhet och i enskilda fall. För att utreda rättsläget används en rättsdogmatisk metod som kompletteras med en analys av naturvetenskapligt material för att klargöra vilka faktiska effekter IAS har. Miljörätten inom EU baseras på försiktighetsprincipen och den nyligen (relativt) utfärdade IAS-förordningen baseras därefter på försiktighetsprincipen. Det måste dock utföras en riskbedömning innan arter omfattas av IAS-förordningens bestämmelser (och legalt definieras som IAS inom EU). Försiktighetsprincipen (en stark version) ska emellertid betyda att en antagen risk är tillräckligt för att åtgärder ska vidtas; genom riskbedömningen betyder det däremot att det handlar om en fastställd risk. Detta betyder även att den faktiska definitionen IAS och den legala är olik; en art kan uppfylla definitionen IAS i praktiken men inte legalt. Försiktighetsprincipen (en stark version) tillämpas därför på legalt definierade IAS inom EU medan de facto IAS inte åtnjuter samma grad av försiktighet.  EU har själva yttrat, i det första skälet i IAS-förordningen, att det existerar 12 000 främmande arter inom EU varav 1800 av dessa är invasiva; IAS-förordningen omfattar dock endast 49 av dessa arter.

International law today is a discipline rife with dissensions. This is largely because international law has meant different things to different generations of scholars and nation-states. In 1996 a United States circuit court in Atlanta affirmed a civil judgment against an Ethiopian defendant in an action initiated by Ethiopian citizens for violations of that country’s law and international law. But about a decade earlier in 1984 another appeal court denied to enforce claims against Libyan and Palestinian defendants under international law because according to the court, international law is dedicated exclusively to the relationship between independent states and not their citizens. Although such different interpretations may appear startling, over the previous centuries, courts have eschewed one view while embracing the other. It is thus imperative to examine what constitutes international law or under what authority a U.S. court could challenge another state’s treatment of its own citizens, in its own land, under its own laws. The Judiciary Act of 1789 which created the Alien Tort Statute, a relatively obscure piece of legislation is at the center of these actions. But what was the original intent of the Alien Tort Statute? Is it possible to reconstruct the meaning of that statute? To answer these questions, this dissertation critically interrogated the meaning of international law and the law of nations as it existed at the time of the founding of the United States. What was called the law of nations and subsequently international law revealed multiple meanings. In unpacking the history of the Alien Tort Statute, this dissonance was reflected in the conflicts which assailed the discipline. This dissertation therefore reproduces the dissensions as it analyzes and reconstructs a hitherto unexplored front in this debacle: lawsuits filed by some Africans in the United States under the Alien Tort Statute against their leaders and corporations for egregious human rights violations in Africa. In the end therefore, the issue becomes, can justice and reparations be achieved in United States courts for human rights violations committed in Africa?

Skogsmård (Martes martes) har länge varit Sveriges enda mårdart men 2018 gjordes det första fyndet av en annan art, stenmård (Martes foina), i nordöstra Skåne. Efter att detta fynd uppmärksammats fick Invasiva Arter på Svenska Jägareförbundet in uppgifter om ytterligare tre fynd från området. Syftet med studien var således att undersöka om stenmård är en etablerad art i nordöstra Skåne samt att undersöka om det finns släktskap mellan de funna individerna. Utifrån tidigare fyra fynd utfördes en fältstudie för att försöka samla in ytterligare fynd av stenmård i nordöstra Skåne, med hjälp av fällfångst. Fältstudien utfördes 1 november 2020–28 februari 2021 vilket motsvarade jakttiden för mård i Skåne. Inga nya fynd av stenmård gjordes under fältstudien, men sju fynd rapporterades in från allmänheten inom studieområdet. Således har totalt elva bekräftade fynd gjorts i Sverige åren 2014–2021, samtliga i nordöstra Skåne. Genetiska analyser utfördes av Naturhistoriska riksmuseet på fyra av kadavren för att undersöka eventuellt släktskap mellan dem, genom att jämföra individernas mitokondrie-DNA. Resultatet visade att de fyra individerna hade samma haplotyp och således härstammar från en gemensam anmoder. Utifrån åldersbestämning och tidpunkt för fällning kunde även bekräftas att de fyra individerna härstammar från minst två kullar och därmed att föryngring skett i området. Vi bedömer stenmård som en etablerad främmande art i nordöstra Skåne, eftersom den inom historisk tid inte ingått i Sveriges fauna och eftersom föryngring bekräftats. Vidare bedömdes att artens potential att klassas som invasiv bör utredas ytterligare utifrån ekologiska, ekosystemrelaterade och ekonomiska aspekter. / Pine marten (Martes martes) was the only marten species in Sweden until 2018 when the first stone marten (Martes foina) was found in the north-east of Scania. When this finding becamepublic, four more records from the area were reported to the Swedish association for hunting and wildlife management. In this study it was investigated if the stone marten is an established species in the north-east of Scania and if there is a genetic relationship between the found individuals. Based on the localization of previous records, a trapping field study was performed to see if further records of stone marten could be made in the north-east of Scania. The field study was executed between 1 November 2020-28 February 2021, which is within the hunting season of martens in the area. The field study did not result in any new records, but in seven new reports from the public within the area. In summary, a total of eleven stone marten records have been made in Sweden 2014-2021, all in the north-east of Scania. The Swedish Museum of Natural History in Stockholm performed genetic analyses offour of the cadavers to investigate their genetic relationship by comparing mitochondrial DNA. Results showed that the four individuals had the same haplotype and therefore originate from one common ancestral female. Based on age determination and time of death it was also confirmed that the four individuals originate from at least two litters and that reproduction has occurred in the area. Since the stone marten historically is not part of theSwedish fauna and since local reproduction was confirmed, it was concluded that the species is an established alien species. It was also concluded that the species potential to be classified as invasive should be further investigated based on ecological, ecosystem related and economical aspects.