Thesis (Ph. D.)--Griffith University, 2002. / Title from PDF title page (viewed on May 8, 2005). Includes bibliographical references (p. 136-156).

Thesis (M. Sc.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 103-115). Also available via the World Wide Web.

No description available.

From all the species that arrive to a novel environment, very few manage to form a viable population. The guppy, a very successful invader, is a highly social species that performs some of its vital tasks (e.g., foraging, avoiding predators) in groups. This thesis aimed to quantify heterospecific association benefits that enhance invasion success. Interactions between invaders and natives could be one of the environmental characteristics of a place that increase its risk of invasion. I evaluated the tendency of an invasive species to associate with native individuals with similar ecological requirements. I tested the hypothesis that invaders gain exploring, acquisition of information and foraging benefits when socializing with natives. In these experiments I used the guppy as the invasive model species and endangered native Mexican topminnows (Poeciliopsis infans, Skiffia bilineata, Ameca splendens, Zoogoneticus tequila, Xenotoca eiseni and Girardinichthys viviparous). I found that guppies shoal with other species in Trinidad (Poecilia picta and Poecilia sphenops), where they are native (Chapter 2) and that this trait remains when they are invasive (Chapter 3). Guppies are equally willing to explore novel environments when accompanied by heterospecifics or conspecifics. Guppies are more willing to explore complex environments than simple ones. Moreover, when exploring simple environments they have a higher association tendency, regardless of the partner' species (Chapter 4), which could lead them to acquire the benefits of grouping behaviour and avoid Allee effects - the disadvantages of being part of a small group. In the contexts in which they were tested guppies gained as much information by associating with heterospecifics as with conspecifics (Chapter 5). Finally, I found that when shoaling in bigger shoals guppies are able to locate food faster and spent more time foraging. The benefits of increased shoal size were maintained when the additional guppies were replaced with heterospecifics. However, they derive more benefits from the species they are more willing to associate with (Chapter 6). These results uncover a mechanism enabling founding individuals to survive during the most vulnerable phase of an invasion and help explain why guppies have established viable populations in many parts of Mexico as well as in every continent except Antarctica.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Habitat loss and fragmentation are major threats to global biodiversity. A cornerstone of traditional conservation involves setting aside land as formally protected areas (PAs). However, for effective biological conservation in the long term there needs to be connectivity between these PAs. When possible, improved connectivity can be achieved using natural corridors at a landscape scale. Even better is to establish a network of corridors and nodes in the form of ecological networks (ENs). ENs are currently being employed by commercial forestry companies in South Africa. While larger corridors and nodes are considered optimum, factors other than design, such as management and environmental heterogeneity, have also been found to be important for species maintenance. This study aims to explore the role of corridor width in driving the composition of invertebrate assemblages across a transformed landscape in KwaZulu-Natal, South Africa, and to investigate other possible environmental variables significant for species distributions. In Chapter 2, I investigated the contribution of smaller grassland corridors within a timber production matrix to overall biodiversity conservation using two important bioindicator taxa. Ants and dung beetles were sampled in grassland corridors of three size classes, plantation blocks and a nearby PA, iMpendle Nature Reserve. The two taxa showed differential responses to landscape level fragmentation. Dung beetles showed a decrease in species richness and corresponding increase in species turnover with increased fragmentation, while ants were unaffected, although counter intuitively smaller corridors even contained more unique ant species compared to larger corridors. Dung beetle assemblages also showed strong differences between the PA and grassland corridors. While the conservation effectiveness of large corridors undoubtedly exceeds that of smaller corridors, for ants it seems that smaller corridors contribute to their overall conservation within this production landscape. In Chapter 3, I explore the importance of spatial and environmental factors for species distribution across this landscape. Dung beetles were split into functional guilds according to size and nesting behaviour for analyses. Within grassland corridors, tunnelling dung beetle species richness was sensitive to landscape level fragmentation, especially for larger species, while elevation and vegetation type influenced ant species richness. Since rolling dung beetles showed a close association with the PA, the marked difference in dung beetle assemblages between these two land-uses may be due to the presence of pellet producing grazers in the protected area and their replacement by pat producing cattle in the grassland corridors. Other environmental variables that were found to be important for dung beetle species composition were elevation, vegetation type, and soil hardness. For ant species composition, only elevation was found to be important. In conclusion, as large corridors were comparable to the PA in dung beetle and ant species richness, ENs act as extensions of formally PAs, given that they are large enough. Nevertheless, smaller corridors had surprisingly high species richness. Including additional information other than species data improved our knowledge of the underlying factors that drive dung beetle species composition. Even though dung beetle and ant species responded differentially to habitat fragmentation, environmental heterogeneity seemed important for both taxa. Incorporating habitat heterogeneity into the current management scheme may improve the conservation effectiveness within this transformed landscape. / AFRIKAANSE OPSOMMING: Die vermindering en fragmentasie van natuurlike habitat is ‘n groot bedreiging vir globale biodiversiteit. ‘n Belangrike tradisionele benadering tot natuurbewaring behels die afbakening van land vir formele beskermde areas (BAs). Ten einde effektiewe biologiese bewaring oor die langtermyn te verseker moet daar verbinding wees tussen hierdie BAs. Indien moontlik kan verbeterde verbinding verkry word deur die gebruik van natuurlike gange op ʼn landskaps-vlak. Nog beter is om ʼn netwerk van gange en nodes in die vorm van ekologies netwerke (ENe) saam te stel. ENe word tans deur kommersiële bosboumaatskappye in Suid Afrika aangewend. Terwyl groter gange en nodes as optimaal beskou word, is ander faktore behalwe ontwerp, soos bestuur en omgewingsheterogeniteit, ook al gevind as belangrik vir die onderhouding van spesies. Hierdie studie is gemik daarop om die rol van gangwydte as dryfkrag vir die samestelling van invertebraatversamelings oor ʼn getransformeerde landskap in KwaZulu-Natal, Suid-Afrika, te ondersoek, asook ander moontlike omgewingsveranderlikes wat belangrik vir spesiesverpreidings kan wees. In Hoofstuk 2 het ek die bydrae van kleiner gange tot totale biodiversiteit-bewaring ondersoek deur twee belangrike bio-indikator taxa te bestudeer. Miere en miskruiers is versamel in grasland-gange van drie grootte-klasse, plantasie blokke en ‘n naby geleë BA, iMpendle Natuurreservaat. Die twee taxa het verskillende reaksies tot landskaps-vlak fragmentasie getoon. Miskruiers het ‘n verlaging in spesiesrykheid en ‘n gesamentlike verhoging in spesiesomset met verhoogde fragmentasie gewys, terwyl miere nie geaffekteer is nie, alhoewel kleiner gange het trouens meer unieke mierspesies bevat as groter gange. Die miskruierversamelings in die BA het ook opmerklik verskil van dié in die grasland-gange. Alhoewel die bewaringsdoeltreffendheid van groot gange beslis dié van kleiner gange oorskry, kom dit voor dat kleiner gange wel bydra tot die totale bewaring van miere binne hierdie produksielandskap. In Hoofstuk 3 het ek die belangrikheid van ruimtelike en omgewingsfaktore vir spesiesverspreiding oor hierdie landskap ondersoek. Miskruiers is ook in funksionele groepe verdeel volgens grootte en nes-gedrag vir aparte analise. Binne grasland-gange was tonnellende miskruierspesies sensitief vir landskaps-vlak fragmentasie, veral groter spesies, terwyl hoogte bo seevlak en vegetasie tipe mier spesiesrykheid beïnvloed het. Aangesien rollende miskruierspesies ‘n nabye assosiasie met die BA gewys het, mag die opmerklike verskil in miskruier versamelings tussen hierdie twee grondgebruike ʼn gevolg wees van die aanwesigheid van korrel-mis produserend beweiders in die BA en hulle vervanging deur nat-mis produserende beeste in die grasland-gange. Omgewingsveranderlikes uitsluitende ganggrootte wat belangrik gevind is vir miskruier spesiessamestelling was hoogte bo seevlak, vegetasie tipe en grond-hardheid. Vir mier spesiessamestelling was slegs hoogte bo seevlak belangrik. Om af te sluit, aangesien groot gange vergelykbaar was met die BA in miskruier en mier spesiesrykheid, tree ENe op as uitbreidings van BAs, mits hulle groot genoeg is. Desnieteenstaande het kleiner gange ‘n verbasende hoë spesiesrykheid gehad, veral onder miere. Die insluiting van addisionele inligting buiten spesiesdata het ons kennis van die onderliggende faktore wat miskruier spesiessamestelling dryf verbeter. Alhoewel miskruier- en mierspesies verskillend gereageer het op habitat fragmentasie, het dit voorgekom asof omgewingsheterogeniteit belangrik was vir die spesiesverspreiding van beide taxa. Die insluiting van habitatheterogeniteit binne die huidige bestuursplan mag die doeltreffendheid van bewaring binne hierdie getransformeerde landskap verbeter.

No description available.

Over two thousand environmental, non-governmental organizations (ENGOs) exist in Canada, many of which are concerned with biodiversity. This thesis documents a participatory action research (PAR) project that was designed to identify and explore effective ENGO strategies for protecting biodiversity, key barriers that impede progress, and to develop actions for overcoming the barriers. The qualitative findings and outcomes, which are the product of interviews and workshops conducted over a fifteen month period, primarily with eleven selected ENGOs, are discussed and recommendations made. These results have been used to identify key principles to enable ENGOs to design more effective programs. To adequately protect biodiversity, many new programs, from local, highly specific to global and broad, will be needed. The study emphasizes the importance of both ENGOs and the general public being involved in such programs, and of focusing on the underlying causes, and not the symptoms, of the biodiversity crisis.

Invasive weeds inflict significant harm on native species, ecosystem processes, and natural disturbance regimes. When managing these weed threats, some of the most useful tools are the outputs of predictive distribution models. As they supplement existing distribution data to assess where in the landscape is most susceptible to weed invasion, they allow for more efficient weed management because the areas most suited to weed species may be targeted for control. This research develops a habitat suitability model for the weed lantana (Lantana camara L. sensu lato) in a portion of the Greater Blue Mountains World Heritage Area at present and under forecast warmer climates. A generalised additive model (GAM) is used, which fits the regression curve used for prediction to the calibration data themselves and allows for an exploration of which environmental conditions favour lantana as well as where in the landscape is most suitable for the weed. Temperature was positively correlated with suitable habitat and explained over 90% of the variation in lantana presence predicted by the model. 15% of the study area was found to be suitable for lantana at present, with this figure reaching 58% after a simulated 3??C rise in temperature. Mapping habitat suitability across the study area allowed for the identification of five distinct pathways for lantana to further invade the Blue Mountains. Responding to calls for the integration of weed management with biodiversity conservation, the research also integrates the habitat suitability model with information regarding the distribution of vegetation communities and endangered species in the Blue Mountains. Thirteen native vegetation communities were found to have more than 20% suitable habitat for lantana at present, and an additional three contained more than 80% suitable habitat after a simulated 3??C rise in temperature. Five of these communities are listed as threatened under relevant legislation and harbour at least 27 endangered species, placing additional urgency on their conservation. This research has successfully used modelling techniques to identify areas for targeted weed management integrated with biodiversity conservation. The methods are easily adaptable to other weeds and regions and could thus be used to illustrate the comprehensive threat weeds pose to Australia???s biodiversity.

Invasive weeds inflict significant harm on native species, ecosystem processes, and natural disturbance regimes. When managing these weed threats, some of the most useful tools are the outputs of predictive distribution models. As they supplement existing distribution data to assess where in the landscape is most susceptible to weed invasion, they allow for more efficient weed management because the areas most suited to weed species may be targeted for control. This research develops a habitat suitability model for the weed lantana (Lantana camara L. sensu lato) in a portion of the Greater Blue Mountains World Heritage Area at present and under forecast warmer climates. A generalised additive model (GAM) is used, which fits the regression curve used for prediction to the calibration data themselves and allows for an exploration of which environmental conditions favour lantana as well as where in the landscape is most suitable for the weed. Temperature was positively correlated with suitable habitat and explained over 90% of the variation in lantana presence predicted by the model. 15% of the study area was found to be suitable for lantana at present, with this figure reaching 58% after a simulated 3??C rise in temperature. Mapping habitat suitability across the study area allowed for the identification of five distinct pathways for lantana to further invade the Blue Mountains. Responding to calls for the integration of weed management with biodiversity conservation, the research also integrates the habitat suitability model with information regarding the distribution of vegetation communities and endangered species in the Blue Mountains. Thirteen native vegetation communities were found to have more than 20% suitable habitat for lantana at present, and an additional three contained more than 80% suitable habitat after a simulated 3??C rise in temperature. Five of these communities are listed as threatened under relevant legislation and harbour at least 27 endangered species, placing additional urgency on their conservation. This research has successfully used modelling techniques to identify areas for targeted weed management integrated with biodiversity conservation. The methods are easily adaptable to other weeds and regions and could thus be used to illustrate the comprehensive threat weeds pose to Australia???s biodiversity.

Invasive weeds inflict significant harm on native species, ecosystem processes, and natural disturbance regimes. When managing these weed threats, some of the most useful tools are the outputs of predictive distribution models. As they supplement existing distribution data to assess where in the landscape is most susceptible to weed invasion, they allow for more efficient weed management because the areas most suited to weed species may be targeted for control. This research develops a habitat suitability model for the weed lantana (Lantana camara L. sensu lato) in a portion of the Greater Blue Mountains World Heritage Area at present and under forecast warmer climates. A generalised additive model (GAM) is used, which fits the regression curve used for prediction to the calibration data themselves and allows for an exploration of which environmental conditions favour lantana as well as where in the landscape is most suitable for the weed. Temperature was positively correlated with suitable habitat and explained over 90% of the variation in lantana presence predicted by the model. 15% of the study area was found to be suitable for lantana at present, with this figure reaching 58% after a simulated 3??C rise in temperature. Mapping habitat suitability across the study area allowed for the identification of five distinct pathways for lantana to further invade the Blue Mountains. Responding to calls for the integration of weed management with biodiversity conservation, the research also integrates the habitat suitability model with information regarding the distribution of vegetation communities and endangered species in the Blue Mountains. Thirteen native vegetation communities were found to have more than 20% suitable habitat for lantana at present, and an additional three contained more than 80% suitable habitat after a simulated 3??C rise in temperature. Five of these communities are listed as threatened under relevant legislation and harbour at least 27 endangered species, placing additional urgency on their conservation. This research has successfully used modelling techniques to identify areas for targeted weed management integrated with biodiversity conservation. The methods are easily adaptable to other weeds and regions and could thus be used to illustrate the comprehensive threat weeds pose to Australia???s biodiversity.