The importance of long-term post-release studies in classical biological control: Insect–plant monitoring and public awareness of water hyacinth management (Pontederia crassipes) in Dique Los Sauces, Argentina
- Faltlhauser, Ana C, Jiménez, Nadia L, Righetti, Tomas, Visintin, Andrés M, Torrens, Javier, Salinas, Nicolás A, Mc Kay, Fernando, Hill, Martin P, Cordo, Hugo A, Sosa, Alejandro J
- Authors: Faltlhauser, Ana C , Jiménez, Nadia L , Righetti, Tomas , Visintin, Andrés M , Torrens, Javier , Salinas, Nicolás A , Mc Kay, Fernando , Hill, Martin P , Cordo, Hugo A , Sosa, Alejandro J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424828 , vital:72187 , xlink:href="https://doi.org/10.1111/eea.13355"
- Description: Several components of classical biological control (CBC) programmes are necessary to assess the success of the management strategy (e.g., post-release monitoring) and also help prevent reintroductions or resurgences of invasive species (e.g., public awareness). Water hyacinth, Pontederia (= Eichhornia) crassipes (Mart.) Solms (Pontederiaceae) is an aquatic plant naturally distributed in the north-eastern region of the Del Plata basin in Argentina. In the 1960s it was introduced into the Dique Los Sauces reservoir located outside of its native range in La Rioja Province, in western Argentina, where it became invasive. The natural enemy, Neochetina bruchi Hustache (Coleoptera: Curculionidae), was intentionally introduced in 1974 to control the weed. To assess the success of this CBC programme, a long-term post-release study was conducted. Between 1965 and 2023, we monitored plant coverage, estimated N. bruchi densities, and quantified the associated damage by reanalysing previously published data and incorporating new sampling. We also conducted an online survey to analyse public knowledge and perception about this programme. Water hyacinth coverage fluctuated from its first record in 1965 (maximum coverage 90%) until the control of germinated plants (coverage 0%) in 2018. The plant decline was accompanied by an increase in the weevil population. In our survey, out of 325 respondents only a small group of mostly middle-aged and elderly people knew that the restoration had been achieved through a management strategy and even fewer were aware of the biocontrol approach taken. Respondents who had a positive approach to biological control were more aware of the management plan than respondents who had neutral or negative opinions. Neochetina bruchi has played a key factor in the control of P. crassipes. The intrinsic dynamics of these populations, the dormant seed bank, and the lack of public awareness support the need for long post-release evaluations including outreach campaigns to make a sustainable successful management programme.
- Full Text:
- Date Issued: 2023
- Authors: Faltlhauser, Ana C , Jiménez, Nadia L , Righetti, Tomas , Visintin, Andrés M , Torrens, Javier , Salinas, Nicolás A , Mc Kay, Fernando , Hill, Martin P , Cordo, Hugo A , Sosa, Alejandro J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424828 , vital:72187 , xlink:href="https://doi.org/10.1111/eea.13355"
- Description: Several components of classical biological control (CBC) programmes are necessary to assess the success of the management strategy (e.g., post-release monitoring) and also help prevent reintroductions or resurgences of invasive species (e.g., public awareness). Water hyacinth, Pontederia (= Eichhornia) crassipes (Mart.) Solms (Pontederiaceae) is an aquatic plant naturally distributed in the north-eastern region of the Del Plata basin in Argentina. In the 1960s it was introduced into the Dique Los Sauces reservoir located outside of its native range in La Rioja Province, in western Argentina, where it became invasive. The natural enemy, Neochetina bruchi Hustache (Coleoptera: Curculionidae), was intentionally introduced in 1974 to control the weed. To assess the success of this CBC programme, a long-term post-release study was conducted. Between 1965 and 2023, we monitored plant coverage, estimated N. bruchi densities, and quantified the associated damage by reanalysing previously published data and incorporating new sampling. We also conducted an online survey to analyse public knowledge and perception about this programme. Water hyacinth coverage fluctuated from its first record in 1965 (maximum coverage 90%) until the control of germinated plants (coverage 0%) in 2018. The plant decline was accompanied by an increase in the weevil population. In our survey, out of 325 respondents only a small group of mostly middle-aged and elderly people knew that the restoration had been achieved through a management strategy and even fewer were aware of the biocontrol approach taken. Respondents who had a positive approach to biological control were more aware of the management plan than respondents who had neutral or negative opinions. Neochetina bruchi has played a key factor in the control of P. crassipes. The intrinsic dynamics of these populations, the dormant seed bank, and the lack of public awareness support the need for long post-release evaluations including outreach campaigns to make a sustainable successful management programme.
- Full Text:
- Date Issued: 2023
Morphological variations in southern African populations of Myriophyllum spicatum: Phenotypic plasticity or local adaptation?
- Weyl, Philip S, Coetzee, Julie A
- Authors: Weyl, Philip S , Coetzee, Julie A
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424789 , vital:72184 , xlink:href="https://doi.org/10.1016/j.sajb.2015.07.01"
- Description: Variability in aquatic plant morphology is usually driven by phenotypic plasticity and local adaptations to environmental conditions experienced. This study aimed to elucidate which of these drivers is responsible for the morphological variation exhibited by three populations of Myriophyllum spicatum L. (Haloragaceae), a submerged aquatic plant whose status as native or exotic within southern Africa is uncertain. Individuals from three populations on the Vaal River (Northern Cape), Klipplaat River (Eastern Cape) and Lake Sibaya (KwaZulu-Natal) were grown under two nutrient treatments (high: 30 mg N/kg sediment and low: sediment only), while all other variables were kept the same. Morphological characteristics were measured at the start of the experiment to obtain a baseline morphology, and again eight weeks later. By the end of the experiment, the individuals from each population had responded to the different growing conditions. In most cases, the individuals from each population were significantly larger under the high nutrient treatment (Stem diameter: F(5,86) = 18.435, P is less than 0.001, Internode length: F(5,86) = 5.0747, P is less than 0.001, Leaf length: F(5,86) = 19.692, P is less than 0.001). Despite these differences in nutrient treatments, the growth pattern of each population remained true to the original starting point indicated by the lack of overlap between populations in the PCA groupings. This suggests that local adaptations are responsible for the differences in morphology between populations of M. spicatum, but shows that phenotypic plasticity does play a role as evidenced by individual responses to the different nutrient conditions. The development of these local adaptations within southern Africa suggests that the populations have had a long evolutionary history in the region and are relatively isolated with little reproductive mixing.
- Full Text:
- Date Issued: 2016
- Authors: Weyl, Philip S , Coetzee, Julie A
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424789 , vital:72184 , xlink:href="https://doi.org/10.1016/j.sajb.2015.07.01"
- Description: Variability in aquatic plant morphology is usually driven by phenotypic plasticity and local adaptations to environmental conditions experienced. This study aimed to elucidate which of these drivers is responsible for the morphological variation exhibited by three populations of Myriophyllum spicatum L. (Haloragaceae), a submerged aquatic plant whose status as native or exotic within southern Africa is uncertain. Individuals from three populations on the Vaal River (Northern Cape), Klipplaat River (Eastern Cape) and Lake Sibaya (KwaZulu-Natal) were grown under two nutrient treatments (high: 30 mg N/kg sediment and low: sediment only), while all other variables were kept the same. Morphological characteristics were measured at the start of the experiment to obtain a baseline morphology, and again eight weeks later. By the end of the experiment, the individuals from each population had responded to the different growing conditions. In most cases, the individuals from each population were significantly larger under the high nutrient treatment (Stem diameter: F(5,86) = 18.435, P is less than 0.001, Internode length: F(5,86) = 5.0747, P is less than 0.001, Leaf length: F(5,86) = 19.692, P is less than 0.001). Despite these differences in nutrient treatments, the growth pattern of each population remained true to the original starting point indicated by the lack of overlap between populations in the PCA groupings. This suggests that local adaptations are responsible for the differences in morphology between populations of M. spicatum, but shows that phenotypic plasticity does play a role as evidenced by individual responses to the different nutrient conditions. The development of these local adaptations within southern Africa suggests that the populations have had a long evolutionary history in the region and are relatively isolated with little reproductive mixing.
- Full Text:
- Date Issued: 2016
Two in one: cryptic species discovered in biological control agent populations using molecular data and crossbreeding experiments
- Paterson, Iain D, Mangan, Rose, Downie, Douglas A, Coetzee, Julie A, Hill, Martin P, Burke, Ashley M, Downey, Paul O, Henry, Thomas J, Compton, Stephen G
- Authors: Paterson, Iain D , Mangan, Rose , Downie, Douglas A , Coetzee, Julie A , Hill, Martin P , Burke, Ashley M , Downey, Paul O , Henry, Thomas J , Compton, Stephen G
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424877 , vital:72191 , xlink:href="https://doi.org/10.1002/ece3.2297"
- Description: There are many examples of cryptic species that have been identified through DNA-barcoding or other genetic techniques. There are, however, very few confirmations of cryptic species being reproductively isolated. This study presents one of the few cases of cryptic species that has been confirmed to be reproductively isolated and therefore true species according to the biological species concept. The cryptic species are of special interest because they were discovered within biological control agent populations. Two geographically isolated populations of Eccritotarsus catarinensis (Carvalho) [Hemiptera: Miridae], a biological control agent for the invasive aquatic macrophyte, water hyacinth, Eichhornia crassipes (Mart.) Solms [Pontederiaceae], in South Africa, were sampled from the native range of the species in South America. Morphological characteristics indicated that both populations were the same species according to the current taxonomy, but subsequent DNA analysis and breeding experiments revealed that the two populations are reproductively isolated. Crossbreeding experiments resulted in very few hybrid offspring when individuals were forced to interbreed with individuals of the other population, and no hybrid offspring were recorded when a choice of mate from either population was offered. The data indicate that the two populations are cryptic species that are reproductively incompatible. Subtle but reliable diagnostic characteristics were then identified to distinguish between the two species which would have been considered intraspecific variation without the data from the genetics and interbreeding experiments. These findings suggest that all consignments of biological control agents from allopatric populations should be screened for cryptic species using genetic techniques and that the importation of multiple consignments of the same species for biological control should be conducted with caution.
- Full Text:
- Date Issued: 2016
- Authors: Paterson, Iain D , Mangan, Rose , Downie, Douglas A , Coetzee, Julie A , Hill, Martin P , Burke, Ashley M , Downey, Paul O , Henry, Thomas J , Compton, Stephen G
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424877 , vital:72191 , xlink:href="https://doi.org/10.1002/ece3.2297"
- Description: There are many examples of cryptic species that have been identified through DNA-barcoding or other genetic techniques. There are, however, very few confirmations of cryptic species being reproductively isolated. This study presents one of the few cases of cryptic species that has been confirmed to be reproductively isolated and therefore true species according to the biological species concept. The cryptic species are of special interest because they were discovered within biological control agent populations. Two geographically isolated populations of Eccritotarsus catarinensis (Carvalho) [Hemiptera: Miridae], a biological control agent for the invasive aquatic macrophyte, water hyacinth, Eichhornia crassipes (Mart.) Solms [Pontederiaceae], in South Africa, were sampled from the native range of the species in South America. Morphological characteristics indicated that both populations were the same species according to the current taxonomy, but subsequent DNA analysis and breeding experiments revealed that the two populations are reproductively isolated. Crossbreeding experiments resulted in very few hybrid offspring when individuals were forced to interbreed with individuals of the other population, and no hybrid offspring were recorded when a choice of mate from either population was offered. The data indicate that the two populations are cryptic species that are reproductively incompatible. Subtle but reliable diagnostic characteristics were then identified to distinguish between the two species which would have been considered intraspecific variation without the data from the genetics and interbreeding experiments. These findings suggest that all consignments of biological control agents from allopatric populations should be screened for cryptic species using genetic techniques and that the importation of multiple consignments of the same species for biological control should be conducted with caution.
- Full Text:
- Date Issued: 2016
Molecular identification of Azolla invasions in Africa: The Azolla specialist, Stenopelmus rufinasus proves to be an excellent taxonomist
- Madeira, P T, Dray, F Allen, Coetzee, Julie A, Paterson, Iain D, Tipping, Philip W
- Authors: Madeira, P T , Dray, F Allen , Coetzee, Julie A , Paterson, Iain D , Tipping, Philip W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424765 , vital:72182 , xlink:href="https://doi.org/10.1016/j.sajb.2016.03.007"
- Description: Biological control of Azolla filiculoides in South Africa with the Azolla specialist Stenopelmus rufinasus has been highly successful. However, field surveys showed that the agent utilized another Azolla species, thought to be the native Azolla pinnata subsp. africana, which contradicted host specificity trials. It is notoriously difficult to determine Azolla species based on morphology so genetic analyses were required to confirm the identity of the Azolla used by the agent. Extensive sampling was conducted and samples were sequenced at the trnL-trnF and trnG-trnR chloroplastic regions and the nuclear ITS1 region. Current literature reported A. filiculoides as the only Section Azolla species in southern Africa but 24 samples were identified as Azolla cristata, an introduced species within Section Azolla that was not used during host specificity trials. A. pinnata subsp. africana was only located at one site in southern Africa, while the alien A. pinnata subsp. asiatica was located at three. What was thought to be A. pinnata subsp. africana was in fact A. cristata, a closer relative of A. filiculoides and a suitable host according to specificity trials. This study confirms that S. rufinasus is a proficient Azolla taxonomist but also supports the use of molecular techniques for resolving taxonomic conundrums.
- Full Text:
- Date Issued: 2016
- Authors: Madeira, P T , Dray, F Allen , Coetzee, Julie A , Paterson, Iain D , Tipping, Philip W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424765 , vital:72182 , xlink:href="https://doi.org/10.1016/j.sajb.2016.03.007"
- Description: Biological control of Azolla filiculoides in South Africa with the Azolla specialist Stenopelmus rufinasus has been highly successful. However, field surveys showed that the agent utilized another Azolla species, thought to be the native Azolla pinnata subsp. africana, which contradicted host specificity trials. It is notoriously difficult to determine Azolla species based on morphology so genetic analyses were required to confirm the identity of the Azolla used by the agent. Extensive sampling was conducted and samples were sequenced at the trnL-trnF and trnG-trnR chloroplastic regions and the nuclear ITS1 region. Current literature reported A. filiculoides as the only Section Azolla species in southern Africa but 24 samples were identified as Azolla cristata, an introduced species within Section Azolla that was not used during host specificity trials. A. pinnata subsp. africana was only located at one site in southern Africa, while the alien A. pinnata subsp. asiatica was located at three. What was thought to be A. pinnata subsp. africana was in fact A. cristata, a closer relative of A. filiculoides and a suitable host according to specificity trials. This study confirms that S. rufinasus is a proficient Azolla taxonomist but also supports the use of molecular techniques for resolving taxonomic conundrums.
- Full Text:
- Date Issued: 2016
Report containing learning, reflection and evaluation based on social learning:
- Burt, Jane C, Wilson, Jessica, Copteros, Athina, Lotz-Sisitka, Heila, Pereira, Taryn, Mokoena, Samson, Munnik, Victor, Ngcozela, Thabang, Lusithi, Thabo
- Authors: Burt, Jane C , Wilson, Jessica , Copteros, Athina , Lotz-Sisitka, Heila , Pereira, Taryn , Mokoena, Samson , Munnik, Victor , Ngcozela, Thabang , Lusithi, Thabo
- Date: 2016
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/142005 , vital:38023 , ISBN WRC Report no K5/2313 Deliverable 7
- Description: This report forms the seventh deliverable in the NWRS2 citizen monitoring project and builds on the previous 6 deliverables, which include methodology for the project (Del 1), an assessment of civil society involvement in water policy (Del 2), an overview of the social learning approach and introduction to the case studies (Del 3), draft citizen monitoring guidelines (Del 4), an update on social learning to-date, including action plans (Del 5) and a report on a description and assessment of the case studies (Del 6). This report describes the last social learning module of the ‘Changing Practice’ course and highlights preliminary reflections on the learning that has taken place during this course. The report also describes the plans that were taken at the follow up research meeting. Finally we present the approach towards evaluating the role of social learning in the project as a whole.
- Full Text:
- Date Issued: 2016
- Authors: Burt, Jane C , Wilson, Jessica , Copteros, Athina , Lotz-Sisitka, Heila , Pereira, Taryn , Mokoena, Samson , Munnik, Victor , Ngcozela, Thabang , Lusithi, Thabo
- Date: 2016
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/142005 , vital:38023 , ISBN WRC Report no K5/2313 Deliverable 7
- Description: This report forms the seventh deliverable in the NWRS2 citizen monitoring project and builds on the previous 6 deliverables, which include methodology for the project (Del 1), an assessment of civil society involvement in water policy (Del 2), an overview of the social learning approach and introduction to the case studies (Del 3), draft citizen monitoring guidelines (Del 4), an update on social learning to-date, including action plans (Del 5) and a report on a description and assessment of the case studies (Del 6). This report describes the last social learning module of the ‘Changing Practice’ course and highlights preliminary reflections on the learning that has taken place during this course. The report also describes the plans that were taken at the follow up research meeting. Finally we present the approach towards evaluating the role of social learning in the project as a whole.
- Full Text:
- Date Issued: 2016
Reviewing strategies in/for ESD policy engagement: Agency reclaimed
- Authors: Lotz-Sisitka, Heila
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182483 , vital:43834 , xlink:href="https://doi.org/10.1080/00958964.2015.1113915"
- Description: In this response article, I draw on critical realist perspectives to engage with the argument put forward in Bengtsson's study, which sees agency as an ontological necessity for Education for Sustainable Development (ESD) policy engagement. Bengtsson supports a notion of the logic of contingent action over the logic of power as dominance, suggesting possibilities for agency and resistance. Although I do not in principle disagree with the agentive possibilities embedded in this aspect of the Bengtsson argument, it is the scope of the conceptualization thereof that I consider in this response. I start with considering the limitations of a Westphalian analysis of policy appropriations and agency for ESD, and argue that the Westphalian frame for policy analysis may be inadequate for capturing the significance of non-state actors and wider generative mechanisms such as informal normative structures, and private, economic power in the global political economy. Drawing on Fraser's (2008) concept of the transnational public sphere, I explore other potential possibilities for agency-centered appropriations or negations of, and/or resistance to ESD policy discourses, potentially expanding the agency-centered perspective referred to in Bengtsson's analysis and critique of policy making for ESD, or, at the very least, by offering a wider view of possibility for what he refers to as the ‘ineradicable moment of conflict, or antagonism.’ In particular, I broaden the notion of the transnational public sphere to be inclusive of Dussel's (1998) three concerns of transformation, namely; poverty and wealth inequality, environmental degradation, and narrow rationalities involving ongoing colonization of people, territories and resources. In doing this, I concur with Fraser, who suggests that the concept of the public sphere may well be “so thoroughly Westphalian in its deep conceptual structure as to be unsalvageable as a critical tool for theorizing the present” and suggest that public sphere thinking and associated conceptions of agency require expansion, which I offer from postcolonial and decolonization literature, critical realism, ontological experiences, and reflection on Environmental Education (EE) /ESD policy in the southern African region. Ultimately, I propose need for a more radical framework for EE/ ESD policy research that reaches beyond analyses of appropriations of policy within the Wesphalian state framework, and that moves beyond critiquing or seeking out resistance moments associated with the assumptions of trickle down effects from UN level policy, or analysis that is centered on the EE versus ESD debate. Such a framework requires a revitalized notion of agency involving commitment to collective, relational (including the socio-materially relational) and transgressive forms of agency for deep societal transformations all round. Overall, it seems that environmental education policy and praxis research conceptualized within a decolonizing transnational sphere frame appears to still be an open and as yet under-explored terrain.
- Full Text:
- Date Issued: 2016
- Authors: Lotz-Sisitka, Heila
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182483 , vital:43834 , xlink:href="https://doi.org/10.1080/00958964.2015.1113915"
- Description: In this response article, I draw on critical realist perspectives to engage with the argument put forward in Bengtsson's study, which sees agency as an ontological necessity for Education for Sustainable Development (ESD) policy engagement. Bengtsson supports a notion of the logic of contingent action over the logic of power as dominance, suggesting possibilities for agency and resistance. Although I do not in principle disagree with the agentive possibilities embedded in this aspect of the Bengtsson argument, it is the scope of the conceptualization thereof that I consider in this response. I start with considering the limitations of a Westphalian analysis of policy appropriations and agency for ESD, and argue that the Westphalian frame for policy analysis may be inadequate for capturing the significance of non-state actors and wider generative mechanisms such as informal normative structures, and private, economic power in the global political economy. Drawing on Fraser's (2008) concept of the transnational public sphere, I explore other potential possibilities for agency-centered appropriations or negations of, and/or resistance to ESD policy discourses, potentially expanding the agency-centered perspective referred to in Bengtsson's analysis and critique of policy making for ESD, or, at the very least, by offering a wider view of possibility for what he refers to as the ‘ineradicable moment of conflict, or antagonism.’ In particular, I broaden the notion of the transnational public sphere to be inclusive of Dussel's (1998) three concerns of transformation, namely; poverty and wealth inequality, environmental degradation, and narrow rationalities involving ongoing colonization of people, territories and resources. In doing this, I concur with Fraser, who suggests that the concept of the public sphere may well be “so thoroughly Westphalian in its deep conceptual structure as to be unsalvageable as a critical tool for theorizing the present” and suggest that public sphere thinking and associated conceptions of agency require expansion, which I offer from postcolonial and decolonization literature, critical realism, ontological experiences, and reflection on Environmental Education (EE) /ESD policy in the southern African region. Ultimately, I propose need for a more radical framework for EE/ ESD policy research that reaches beyond analyses of appropriations of policy within the Wesphalian state framework, and that moves beyond critiquing or seeking out resistance moments associated with the assumptions of trickle down effects from UN level policy, or analysis that is centered on the EE versus ESD debate. Such a framework requires a revitalized notion of agency involving commitment to collective, relational (including the socio-materially relational) and transgressive forms of agency for deep societal transformations all round. Overall, it seems that environmental education policy and praxis research conceptualized within a decolonizing transnational sphere frame appears to still be an open and as yet under-explored terrain.
- Full Text:
- Date Issued: 2016
Encompassing the relative non-target risks from agents and their alien plant targets in biological control assessments
- Downey, Paul O, Paterson, Iain D
- Authors: Downey, Paul O , Paterson, Iain D
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417940 , vital:71496 , xlink:href="https://doi.org/10.1007/s10526-016-9744-1"
- Description: Criticisms about the safety of biological control of alien plants has resulted in a risk-averse approach, where the risks posed by the agent are paramount and the risks posed by the alien plant are neglected. We argue that the risk associated with non-target damage from agents needs to be assessed relative to that of their target alien plants. A literature review of the non-target risks associated with biological control agents was undertaken in terms of the risk to native species from agents relative to the risk to native species from their alien plant targets. We then developed a framework that compares the consequence with the likelihood of non-target damage for both agents and their targets to provide an overall risk rating. Assessments of the risk of damage from both agents and their target alien plants will enable researchers, managers and policy makers to better assess the risks from biological control.
- Full Text:
- Date Issued: 2016
- Authors: Downey, Paul O , Paterson, Iain D
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417940 , vital:71496 , xlink:href="https://doi.org/10.1007/s10526-016-9744-1"
- Description: Criticisms about the safety of biological control of alien plants has resulted in a risk-averse approach, where the risks posed by the agent are paramount and the risks posed by the alien plant are neglected. We argue that the risk associated with non-target damage from agents needs to be assessed relative to that of their target alien plants. A literature review of the non-target risks associated with biological control agents was undertaken in terms of the risk to native species from agents relative to the risk to native species from their alien plant targets. We then developed a framework that compares the consequence with the likelihood of non-target damage for both agents and their targets to provide an overall risk rating. Assessments of the risk of damage from both agents and their target alien plants will enable researchers, managers and policy makers to better assess the risks from biological control.
- Full Text:
- Date Issued: 2016
Forensic entomotoxicology revisited: towards professional standardisation of study designs
- da Silva, Erica I T, Wilhelmi, Brendan S, Villet, Martin H
- Authors: da Silva, Erica I T , Wilhelmi, Brendan S , Villet, Martin H
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140819 , vital:37921 , DOI: 10.1007/s00414-017-1603-9
- Description: Forensic entomotoxicology is the use of insects as evidence of whether a toxicant is present in an environment such as a corpse, river or landscape. The earliest overtly forensic study was published in 1977, and since then, at least 63 papers have been published, most of them focused on the detection of toxicants in insects or on effects of toxicants on diverse insect indicator taxa. A comprehensive review of the published literature revealed various inconsistencies between studies that could be addressed by introducing standard protocols for such studies. These protocols could include selecting widespread and common model organisms (such as Lucilia sericata, Calliphora vicina, Chrysomya megacephala and Dermestes maculatus) and model toxicants (e.g. morphine and amitriptyline) to build up comparative databases; developing a standard matrix for use as a feeding substrate; setting guidelines for statistically adequate sample sizes; and deploying more sophisticated analytical methods from the general field of toxicology.
- Full Text:
- Date Issued: 2017
- Authors: da Silva, Erica I T , Wilhelmi, Brendan S , Villet, Martin H
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140819 , vital:37921 , DOI: 10.1007/s00414-017-1603-9
- Description: Forensic entomotoxicology is the use of insects as evidence of whether a toxicant is present in an environment such as a corpse, river or landscape. The earliest overtly forensic study was published in 1977, and since then, at least 63 papers have been published, most of them focused on the detection of toxicants in insects or on effects of toxicants on diverse insect indicator taxa. A comprehensive review of the published literature revealed various inconsistencies between studies that could be addressed by introducing standard protocols for such studies. These protocols could include selecting widespread and common model organisms (such as Lucilia sericata, Calliphora vicina, Chrysomya megacephala and Dermestes maculatus) and model toxicants (e.g. morphine and amitriptyline) to build up comparative databases; developing a standard matrix for use as a feeding substrate; setting guidelines for statistically adequate sample sizes; and deploying more sophisticated analytical methods from the general field of toxicology.
- Full Text:
- Date Issued: 2017
The pattern-richness of graphical passwords
- Vorster, Johannes, Van Heerden, Renier, Irwin, Barry V W
- Authors: Vorster, Johannes , Van Heerden, Renier , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68322 , vital:29238 , https://doi.org/10.1109/ISSA.2016.7802931
- Description: Publisher version , Conventional (text-based) passwords have shown patterns such as variations on the username, or known passwords such as “password”, “admin” or “12345”. Patterns may similarly be detected in the use of Graphical passwords (GPs). The most significant such pattern - reported by many researchers - is hotspot clustering. This paper qualitatively analyses more than 200 graphical passwords for patterns other than the classically reported hotspots. The qualitative analysis finds that a significant percentage of passwords fall into a small set of patterns; patterns that can be used to form attack models against GPs. In counter action, these patterns can also be used to educate users so that future password selection is more secure. It is the hope that the outcome from this research will lead to improved behaviour and an enhancement in graphical password security.
- Full Text: false
- Date Issued: 2016
- Authors: Vorster, Johannes , Van Heerden, Renier , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68322 , vital:29238 , https://doi.org/10.1109/ISSA.2016.7802931
- Description: Publisher version , Conventional (text-based) passwords have shown patterns such as variations on the username, or known passwords such as “password”, “admin” or “12345”. Patterns may similarly be detected in the use of Graphical passwords (GPs). The most significant such pattern - reported by many researchers - is hotspot clustering. This paper qualitatively analyses more than 200 graphical passwords for patterns other than the classically reported hotspots. The qualitative analysis finds that a significant percentage of passwords fall into a small set of patterns; patterns that can be used to form attack models against GPs. In counter action, these patterns can also be used to educate users so that future password selection is more secure. It is the hope that the outcome from this research will lead to improved behaviour and an enhancement in graphical password security.
- Full Text: false
- Date Issued: 2016