Reassessment of the invasion history of two species of Cakile (Brassicaceae) in Australia

In this paper we revisit the invasion history of two species of Cakile in Australia. Cakile edentula subsp. edentula arrived in the mid 19th Century and spread into coastal strandline habitat from the southeast towards the west and to the north; Cakile maritima arrived in the late 19th Century and has replaced Cakile edentula over much of the range. While Cakile edentula is morphologically quite uniform, the great variation within Cakile maritima has confused field ecologists. Using herbarium records we update previous accounts of the spread of the species and report on field surveys that determined their current geographic overlap in Tasmania and in northern New South Wales/southern Queensland. We examine regional morphological variation within Cakile maritima using the national herbaria collections and variation within new population samples. We support previous interpretations that Cakile maritima has been introduced on more than one occasion from morphologically distinct races, resulting in regional variation within Australia and high variability within populations in the south-east. Western Australian populations appear distinct and probably did not initiate those in the east; we consider that eastern populations are likely to be a mix of Cakile maritima subsp. maritima from the Mediterranean and Cakile maritima subsp. integrifolia from Atlantic Europe. Although introgression from Cakile edentula into Cakile maritima cannot be discounted from our results, it is not required to explain the levels of variation in the latter species observed in Australia. Cakile maritima continues to spread southwards in Tasmania and northwards in NSW; in Queenland, a recent occurrence has proliferated in Moreton Bay, spreading slowly to the north but not appreciably southwards

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

Patterns of genetic and phenotypic variation in invasive Cakile species in Australia

© 2015 Dr. Sara OhadiBiological invasions are one of the key drivers of biodiversity changes. In spite of their environmental and economic impacts, invasive species provide a valuable system for studying evolution over contemporary timescales. However, the complexity of the habitats makes it hard to infer about the evolutionary processes, such as founder events, drift, and admixture and novel selection pressures, in the invasive populations. Invasion studies, however, can benefit from the simplicity of coastal systems where dispersal happens along a linear, one-dimensional habitat with usually less complex biotic interactions. Such a confined habitat makes eco-evolutionary changes in the population more tractable as compared with most two-dimensional terrestrial habitats. My dissertation addresses the patterns of genetic and phenotypic diversity in invasive populations of two coastal species; Cakile maritima and Cakile edentula. These two species have a unique history of invasions in Australia and in two other regions (West coast of North America and New Zealand): in all these three regions C. edentula arrived earlier than C. maritima; however, later on C. maritima replaced C. edentula in most regions. Using these two coastal invaders, the main questions of my thesis were: does variation follow geographical patterns expected from particular invasion mechanisms? If so, what mechanisms predominate? And, does hybridisation/introgression between the two Cakile spp. contribute to population variation and therefore affecting invasion outcomes? These questions were addressed through studies of microsatellite variation on a continental scale, followed up by the use of CAPS markers derived from genome sequencing. A common garden experiment examined phenotypic differences between populations. The species were hand-crossed in the glasshouse to examine the viability and mating systems of hybrid progeny, while putative hybrids from the field were examined using genetic techniques. It is concluded that C. maritima and C. edentula have been introduced to Australia from different sources (multiple introductions). In addition, introgression has occurred through hybridisation between the two species: established populations of each species contain the chloroplast genome of the other species, indicating that bidirectional hybridisation can occur. Furthermore, there was a clinal geographical relationship in phenotypic characteristics for both species: this relationship was stronger for C. edentula than C. maritima, perhaps reflecting post-invasion adaptation to Australian environments

Sex dimorphism in dioecious Palmer amaranth (Amaranthus palmeri) in response to water stress.

Main conclusionPhenological isolation can potentially reduce seed output and may be exploited as a novel tool for ecological management of dioecious weeds. Dioecious plants may benefit from a maximized outcrossing and optimal sex-specific resource allocation; however, this breeding system may also be exploited for weed management. Seed production in dioecious species is contingent upon the co-occurrence and co-flowering of the two genders and can be further disturbed by flowering asynchrony. We explored dimorphism in secondary sex characters in Amaranthus palmeri, and tested if reproductive synchrony can be affected by water stress. We have used seeds of A. palmeri from California, Kansas and Texas, and studied secondary sex characters under natural conditions and in response to water stress. Seeds of A. palmeri from California (CA) and Kansas (KS) were cordially provided by Dr. Anil Shrestha (California State University, Fresno, California) and Dr. Dallas E. Peterson (Kansas State University, Manhattan, Kansas), respectively. Seeds of a third population were collected from mature plants (about 30 plants) from a set-aside field in College Station, Texas. A. palmeri showed no sexual dimorphism with regard to the timing of emergence, plant height, and relative growth rate. While the initiation of flowering occurred earlier in males than females, females preceded males in timing of anthesis. Water stress delayed anthesis in males to a greater extent than females increasing the anthesis mismatch between the two sexes by seven days. Our data provide the first evidence of environment-controlled flowering asynchrony in A. palmeri. From a practical point of view, phenological isolation can potentially reduce seed output and may be exploited as a novel tool for ecological management of dioecious weeds

Surveying the spatial distribution of feral sorghum (Sorghum bicolor L.) and its sympatry with johnsongrass (S. halepense) in South Texas.

Sorghum (Sorghum bicolor) is an important grain and forage crop grown across the US. In some areas, sorghum can become feral along roadsides and other ruderal areas, as a result of seed spill during harvest or transport. In some of these situations, feral sorghum grows in or near established johnsongrass (S. halepense) populations. Johnsongrass, a wild relative of sorghum and an incredibly noxious weed, is capable of hybridizing with cultivated sorghum. Because commercial hybrid sorghum cultivars are produced with cytoplasmic male sterility, progeny of the hybrid crop which compose the founder feral populations also segregate for male sterility. Consequently, male sterility in feral sorghum may increase the risk of outcrossing with johnsongrass. Using field surveys and spatial modelling, the present study aimed at documenting the occurrence of feral sorghum and understanding the anthropogenic and environmental factors that influence its distribution. Further, this research documented the sympatry of feral sorghum and johnsongrass in the roadside habitat. A total of 2077 sites were visited during a systematic field survey conducted in fall 2014 in South Texas. Feral sorghum and johnsongrass were found in 360 and 939 sites, while the species co-existed at 48 sites (2.3% of all surveyed sites). The binary logistic analysis showed a significant association between the presence of feral sorghum and road type, road body-type, micro-topography of the sampling site, nearby land use, and the presence of johnsongrass, but no association with the distance to the nearest grain sorting facility. The probability of finding feral sorghum away from johnsongrass patches was generally higher than finding them co-occur in the same location. A probability map for spatial distribution of feral sorghum was developed using the nearby land use type and the regional habitat suitability for johnsongrass as two key predictors. Overall, results show that feral sorghum and johnsongrass co-occur at low frequencies in the roadside habitats of South Texas, but these low levels still present a significant opportunity for hybridization between the two species outside of cultivated fields

Response of Rice Algal Assemblage to Fertilizer and Chemical Application: Implications for Early Algal Bloom Management

California water-seeded rice is challenged with the rapid growth of nuisance algae at the beginning of the season. Rice seedlings entangled in the algal mat may not be established, causing empty rice patches in the field. Two separate studies were conducted to (1) evaluate the effect of nutrients (nitrogen and phosphorous) on algae growth, and (2) test various chemical options to control algae. Both studies utilized 19 L buckets inoculated with algae collected from a rice field. In the nutrient evaluation study, 36 nutrient treatments obtained from a combination of nitrogen (0, 60, 120, 180, 240 and 300 kg ha−1) and phosphorous (0, 20, 40, 60, 80 and 100 kg ha−1) rates were applied into the buckets, while eight chemicals with potential for algae control (two Protox inhibitor herbicides, four copper-based compounds, hydrogen peroxide, Zinc sulfate) were tested in the second experiment. In addition, a yeast extract-based surfactant (AMP activator) was tested in combination with a chelated copper formulation (Algimycin) and hydrogen peroxide. The studies had a completely randomized design with three replicates and each study was repeated two times. The result from the nutrient evaluation study showed that nitrogen and phosphorus can independently cause change in algae growth as reflected in the fresh and dry biomass. Moreover, low rates of either nitrogen or phosphorus resulted in a rapid increase in algae biomass and water chlorophyll a content, whereas the growth of algae declined at higher rates of applied fertilizer. Among tested chemicals in the second experiment, the chelated formulation of copper (Algimycin PWF) controlled algae (85%) better than the ethanolamine formulations [Cutrine-Ultra (70%) and Cutrine-Plus (52%)] and elemental copper (crystalline copper sulfate) (75%). Protox herbicides (oxyfluorfen and oxadiazon) were able to control algae by up to 70%. Hydrogen peroxide controlled algae by 50% and its efficacy dropped dramatically five days after treatment (DAT). Zinc sulfate was only effective at 1 DAT and algae recovered rapidly after that. Combining fertilizer management practices with chemical options will enable us toward an integrative approach for early algal bloom in the rice cropping system

Data from: Surveying the spatial distribution of feral sorghum (Sorghum bicolor L.) and its sympatry with johnsongrass (S. halepense) in South Texas

Sorghum (Sorghum bicolor) is an important grain and forage crop grown across the US. In some areas, sorghum can become feral along roadsides and other ruderal areas, as a result of seed spill during harvest or transport. In some of these situations, feral sorghum grows in or near established johnsongrass (S. halepense) populations. Johnsongrass, a wild relative of sorghum and an incredibly noxious weed, is capable of hybridizing with cultivated sorghum. Because commercial hybrid sorghum cultivars are produced with cytoplasmic male sterility, progeny of the hybrid crop which compose the founder feral populations also segregate for male sterility. Consequently, male sterility in feral sorghum may increase the risk of outcrossing with johnsongrass. Using field surveys and spatial modelling, the present study aimed at documenting the occurrence of feral sorghum and understanding the anthropogenic and environmental factors that influence its distribution. Further, this research documented the sympatry of feral sorghum and johnsongrass in the roadside habitat. A total of 2077 sites were visited during a systematic field survey conducted in fall 2014 in South Texas. Feral sorghum and johnsongrass were found in 360 and 939 sites, while the species co-existed at 48 sites (2.3% of all surveyed sites). The binary logistic analysis showed a significant association between the presence of feral sorghum and road type, road body-type, micro-topography of the sampling site, nearby land use, and the presence of johnsongrass, but no association with the distance to the nearest grain sorting facility. The probability of finding feral sorghum away from johnsongrass patches was generally higher than finding them co-occur in the same location. A probability map for spatial distribution of feral sorghum was developed using the nearby land use type and the regional habitat suitability for johnsongrass as two key predictors. Overall, results show that feral sorghum and johnsongrass co-occur at low frequencies in the roadside habitats of South Texas, but these low levels still present a significant opportunity for hybridization between the two species outside of cultivated fields

Camelina microcarpa hexaploid and Camelina sativa hybrid data March 12 2018

Information on seed sources, crossing work and characterization of the morphology and fertility of hybrids reared in the green house and field for crosses between Camelina microcarpa (2n = 40; female) and Camelina sativa (2n = 40; male). Metadata on contents is included in the first sheet of the workbook