Guide to the Naturalized and Invasive Plants of Laikipia

The impetus for the development of this Field Guide came about as a result of pleas from the community around the village of Doldol, Laikipia County, to initiate a control programme for Australian prickly pear [Opuntia stricta (Haw.) Haw.; Fabaceae], an invasive plant which was having a dramatic impact on livelihoods. However, a number of other exotic plants, which were less widespread, but had the potential of becoming invasive, were not seen as a potential problem. In order to avoid a similar situation from arising in the future, the community expressed a need for a Field Guide, which would include descriptions of naturalized and invasive species already present in, and those that were most likely to invade Laikipia County and, information on how best to manage them. An additional impetus was to contribute to the four main objectives of the National Strategy and Action Plan for the Management of Invasive Species in Kenya's Protected Areas. The Field Guide contributes in some or other way to all of these objectives which are to (i) Enhance awareness of invasive species to relevant actors; (ii) Prevent new invasions, manage established invasions and rehabilitate degraded habitats; (iii) Enhance research, monitoring and information management on invasive species; and (iv) Enhance capacity, resource mobilization and coordination. Extensive surveys revealed the presence of a number of introduced plant species which had escaped cultivation and established populations in the 'wild' to the detriment of natural resources and the people that depend on them. Introduced succulents, especially those in the genus Opuntia (Cactaceae), were found to be the most widespread and abundant invasive species in the semi-arid regions in the north and east of Laikipia County. Other succulents, those in the genus Bryophyllum (Crassulaceae), were also found to have escaped cultivation and were locally abundant. In the higher rainfall areas to the west and southwest, introduced trees such as black wattle (Acacia mearnsii De Wild.; Fabaceae) and Australian blackwood (Acacia melanoxylon R. Br.; Fabaceae) and the shrubs/climbers, Mauritius thorn [Caesalpinia decapetala (Roth) Alston; Fabaceae] and yellow cestrum (Cestrum aurantiacum Lindl.; Solanaceae), were invasive. Introduced plants, which have the potential to become problematic in Laikipia, unless eradicated or controlled, have also been included in the Guide. This includes species such as famine weed (Parthenium hysterophorus L.; Asteraceae) and 'mathenge' [Prosopis juliflora (Sw.) DC.; Fabaceae], which are already abundant in areas adjoining the County.illustrato

Concurrent validity of VmaxPro, Kinovea, and Speedograph for the assessment of peak barbell velocity during the bench press: A comparison of technological approaches and historical evolutions

Measurement of barbell velocity is a simple and effective way to control strength training. To assess the concurrent validity of different technological approaches measuring barbell velocity, video-analysis (Kinovea), linear velocity transducer (Speedograph), and an inertial measurement unit (VmaxPro) were compared. Sixty-eight female and male sport science students lifted two repetitions in the bench press exercise at self-selected barbell loads. Peak vertical barbell velocity (Vmax) was parallel measured during the concentric phase of the lift using the aforementioned devices. Concordance correlation coefficient (CCC), Deming regression (DR) and Bland-Altman analysis (BA) were used to assess relative and absolute concurrent validity of Vmax measured with Kinovea, Speedograph, and VmaxPro. Results confirmed high concurrent validity of Speedograph and VmaxPro (CCC = 0.99, standard deviation of differences [SDD] = 0.04 m∙s-1) without detecting proportional or constant bias. In contrast, Vmax measured with Kinovea showed poor concurrent validity to Speedograph (CCC = 0.83) and VmaxPro (CCC = 0.81) with significant proportional and constant bias. Regression based re-calibration of Vmax from Kinovea resulted in an SDD = 0.09 m∙s-1 compared to Speedograph and an SDD = 0.08 m∙s-1 compared to VmaxPro. Among the three tested devices, Vmax assessed using Kinovea showed poor concurrent validity. Furthermore, as Kinovea showed proportional bias compared to Speedograph and VmaxPro, application-specific re-calibration of Kinovea should be applied when barbell velocity data is compared to Speedograph and VmaxPro

Biological control of Bryophyllum delagoense (crassulaceae)

Ph.D., Faculty of Science, University of the Witwatersrand, 2011Introduced plants will lose interactions with natural enemies, mutualists and competitors from their native ranges, and possibly gain interactions with new species, under new abiotic conditions in their new environment. The use of biocontrol agents is based on the premise that introduced species are liberated from their natural enemies, although in some cases introduced species may not become invasive because they acquire novel natural enemies. In this study I consider the potential for the biocontrol of Bryophyllum delagoense, a Madagascan endemic, and hypothesize as to why this plant is invasive in Australia and not in South Africa. Of the 33 species of insects collected on B. delagoense in Madagascar, three species, Osphilia tenuipes, Eurytoma bryophylli, and Rhembastus sp. showed potential as biocontrol agents in Australia. Surveys in southern Africa revealed that B. delagoense had acquired 14 species of insects, compared to only two in Australia, which supported the hypothesis that an introduced plant is less likely to become invasive in regions where there are many closely related species. A beetle, Alcidodes sedi, was found to be widespread and damaging in South Africa and also sufficiently host specific for release in Australia. Studies were also undertaken to determine the biology of B. delagoense and characteristics of the recipient environments in Australia and South Africa. Analysis of soils in South Africa found that B. delagoense has the ability to grow on a range of soils and is tolerant of moderate shade. Bryophyllum delagoense exhibited phenotypic plasticity by re-allocating resources to stem production in light-limited; and to root production in nutrient- or water limited, environments. Competition trials indicated that B. delagoense is a weak competitor with overgrazing and the concomitant reduction in fires facilitating invasions. The absence of damaging natural enemies and characteristics of the Australian environment may make it more prone to B. delagoense invasions than in southern Africa. The study indicates that no single trait or group of traits can completely explain the invasive ability of a plant species because the success of an invader often depends on complex interactions between the species and its recipient environment. This has widespread implications for predicting the invasibility of imported plants. Keywords: Alcidodes sedi, biological control, Bryophyllum delagoense, Crassulaceae, Eurytoma bryophylli, fire, invasions, Madagascar, Osphilia tenuipes, Rhembastus sp., soil

Distribution of invasive alien Tithonia (Asteraceae) species in eastern and southern Africa and the socio-ecological impacts of T. diversifolia in Zambia

Background: Many alien plant species, such as Tithonia diversifolia, T. rotundifolia and T. tubaeformis, have been introduced to areas outside of their natural distribution range to provide benefits, but have subsequently become invasive, threatening biodiversity and agricultural productivity. Objectives: The aim of this study was to determine the current distribution and dates of introduction of invasive Tithonia species in eastern and southern Africa and to document the effects of T. diversifolia on rural livelihoods in Zambia. Method: Roadside surveys, and other sources of information, were used to determine the distribution of invasive Tithonia species in eastern and southern Africa. Household interviews were conducted to gauge perceptions and understand the impacts of T. diversifolia on local livelihoods in Zambia’s Copperbelt province. Results: Tithonia diversifolia is widespread in Uganda, Kenya, Tanzania, South Africa, Malawi and parts of Zambia but less so in Zimbabwe. Tithonia rotundifolia was comparatively uncommon in eastern Africa but common in some southern African countries, while T. tubaeformis was invasive in Swaziland, South Africa, Zambia and possibly also Zimbabwe. According to the majority of respondents in Zambia, T. diversifolia has negative impacts on native vegetation, mobility or access, water availability, crop yields and animal health. Conclusion: Invasive Tithonia species are widespread and spreading throughout much of Africa. Livelihood and biodiversity costs have not been considered by those actively promoting the use and further dissemination of T. diversifolia. We therefore recommend that detailed cost–benefit studies should be undertaken to support informed decisions on the future management of these species

Biological invasions in World Heritage Sites: current status and a proposed monitoring and reporting framework

UNESCO World Heritage Sites (WHS) are areas of outstanding universal value and conservation importance. They are, however, threatened by a variety of global change drivers, including biological invasions. We assessed the current status of biological invasions and their management in 241 natural and mixed WHS globally by reviewing documents collated by UNESCO and IUCN. We found that reports on the status of biological invasions in WHS were often irregular or inconsistent. Therefore, while some reports were very informative, they were hard to compare because no systematic method of reporting was followed. Our review revealed that almost 300 different invasive alien species (IAS) were considered as a threat to just over half of all WHS. Information on IAS management undertaken in WHS was available for fewer than half of the sites that listed IAS as a threat. There is clearly a need for an improved monitoring and reporting system for biological invasions in WHS and likely the same for other protected areas globally. To address this issue, we developed a new framework to guide monitoring and reporting of IAS in protected areas building on globally accepted standards for IAS assessments, and tested it on seven WHS. The framework requires the collation of information and reporting on pathways, alien species presence, impacts, and management, the estimation of future threats and management needs, assessments of knowledge and gaps, and, using all of this information allows for an overall threat score to be assigned to the protected area. This new framework should help to improve monitoring of IAS in protected areas moving forward

Global Actions for Managing Cactus Invasions

The family Cactaceae Juss. contains some of the most widespread and damaging invasive alien plant species in the world, with Australia (39 species), South Africa (35) and Spain (24) being the main hotspots of invasion. The Global Cactus Working Group (IOBC GCWG) was launched in 2015 to improve international collaboration and identify key actions that can be taken to limit the impacts caused by cactus invasions worldwide. Based on the results of an on-line survey, information collated from a review of the scientific and grey literature, expertise of the authors, and because invasiveness appears to vary predictably across the family, we (the IOBC GCWG): (1) recommend that invasive and potentially invasive cacti are regulated, and to assist with this, propose five risk categories; (2) recommend that cactus invasions are treated physically or chemically before they become widespread; (3) advocate the use of biological control to manage widespread invasive species; and (4) encourage the development of public awareness and engagement initiatives to integrate all available knowledge and perspectives in the development and implementation of management actions, and address conflicts of interest, especially with the agricultural and ornamental sectors. Implementing these recommendations will require global co-operation. The IOBC GCWG aims to assist with this process through the dissemination of information and experienc

Dissecting the Shared Genetic Architecture of Suicide Attempt, Psychiatric Disorders, and Known Risk Factors

Background Suicide is a leading cause of death worldwide, and nonfatal suicide attempts, which occur far more frequently, are a major source of disability and social and economic burden. Both have substantial genetic etiology, which is partially shared and partially distinct from that of related psychiatric disorders. Methods We conducted a genome-wide association study (GWAS) of 29,782 suicide attempt (SA) cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC). The GWAS of SA was conditioned on psychiatric disorders using GWAS summary statistics via multitrait-based conditional and joint analysis, to remove genetic effects on SA mediated by psychiatric disorders. We investigated the shared and divergent genetic architectures of SA, psychiatric disorders, and other known risk factors. Results Two loci reached genome-wide significance for SA: the major histocompatibility complex and an intergenic locus on chromosome 7, the latter of which remained associated with SA after conditioning on psychiatric disorders and replicated in an independent cohort from the Million Veteran Program. This locus has been implicated in risk-taking behavior, smoking, and insomnia. SA showed strong genetic correlation with psychiatric disorders, particularly major depression, and also with smoking, pain, risk-taking behavior, sleep disturbances, lower educational attainment, reproductive traits, lower socioeconomic status, and poorer general health. After conditioning on psychiatric disorders, the genetic correlations between SA and psychiatric disorders decreased, whereas those with nonpsychiatric traits remained largely unchanged. Conclusions Our results identify a risk locus that contributes more strongly to SA than other phenotypes and suggest a shared underlying biology between SA and known risk factors that is not mediated by psychiatric disorders.Peer reviewe