Fungal Spores in Insect Trapping Fluids: Simultaneous Sampling for Insects and Pathogens

Surveillance for early detection of non-native, invasive pathogens requires simple, sturdy, and easy to use collecting devices. In this study, we compared the fungal species detected in wet collection cups of Lindgren traps versus those detected on slides with oiled cheesecloth as aerial spore collectors. DNA was extracted and amplified from both using the primers ITS1F -ITS7G, and Illumina sequencing was used for metabarcoding of fungi present in samples. In 90 samples there were 1277 fungal OTUs. For fungal OTUs only detected by one collection method, insect traps had three times the number of fungal OTUs compared to slides, and this pattern persisted when analyses were restricted to pathogens and forest pathogens. Annually, thousands of insect traps are deployed in North America and the associated trap fluids have added value in forest disease research and monitoring.

Simulated trampling by cattle negatively impacts invasive Yellow-Flag Iris (Iris pseudacorus) when submerged

Yellow-Flag Iris (Iris pseudacorus L.) is a non-native, invasive wetland plant that disrupts riparian ecosystem processes and is widely distributed across the US and Canada. Due to its physiological and morphological characteristics, I. pseudacorus has the capacity to exclude native vegetation and form extensive monocultures in both lotic and lentic wetland systems. Methods commonly used to manage I. pseudacorus include manual (e.g., hand-pulling, digging) and mechanical (e.g., mowing) treatments for small populations and herbicide applications for larger populations; however, herbicide applications near water may be prohibited due to label restrictions. The objective of this research was to evaluate cattle trampling as a non-chemical method to reduce I. pseudacorus in riparian habitats. A greenhouse study was conducted to investigate the effects of inundation and two different timings of simulated trampling on I. pseudacorus density, height, and soluble sugar concentrations in the rhizomes. A complementary field demonstration was established on a ranch in northwestern Nebraska to evaluate cattle trampling effects on I. pseudacorus density and height after two consecutive years. Simulated cattle trampling in the greenhouse had no effect on I. pseudacorus density or height of non-inundated samples. However, combining trampling with inundation reduced I. pseudacorus density from a median of 10 iris per pot to 0 iris per pot and median height from 0.35 m to 0 m by the conclusion of the study. Additionally, the field demonstration resulted in reductions of both density and height of I. pseudacorus after two consecutive years (72% and 67% reduction, respectively). Soluble sugar concentrations were not impacted by any treatment.

Complex genetic patterns and distribution limits mediated by native congeners of the worldwide invasive red-eared slider turtle

Non-native (invasive) species offer a unique opportunity to study the geographic distribution and range limits of species, wherein the evolutionary change driven by interspecific interactions between native and non-native closely related species is a key component. The red-eared slider turtle, Trachemys scripta elegans (TSE), has been introduced and successfully established worldwide. It can coexist with its native congeners T. cataspila, T. venusta and T. taylori in Mexico. We performed comprehensive fieldwork, executed a battery of genetic analyses and applied a novel species distribution modeling approach to evaluate their historical lineage relationships and contemporary population genetic patterns. Our findings support the historical common ancestry between native TSE and non-native (TSEalien), while also highlighting the genetic differentiation of the exotic lineage. Genetic patterns are associated with their range size/endemism gradient, the microendemic T. taylori showed significant reduced genetic diversity and high differentiation, whereas TSEalien showed the highest diversity and signals of population size expansion. Counter to our expectations, lower naturally occurring distribution overlap and little admixture patterns were found between and its congeners, exhibiting reduced gene flow and clear genetic separation across neighboring species despite having zones of contact. We demonstrate that these native Trachemys species have distinct climatic niche suitability, likely preventing establishment of and displacement by the non-native TSE. Additionally, we found major niche overlap between TSEalien and native species worldwide, supporting our prediction that sites with closer ecological optima to the invasive species have higher establishment risk than those that are closer to the niche-center of the native species.

Standardized invasive species terminology for effective education of Floridians

In this document we introduce a standardized set of seven terms compiled by the members of the UF|IFAS Invasive Species Council that can describe most situations involving invasive species. We do so to promote a common language among Florida’s Extension and outreach professionals. This will limit confusion caused by excessive jargon used to describe invasive species and the fact that much of this jargon is used incorrectly. This confusion hinders stakeholder understanding of environmental and economic impacts caused by invasive species which can prevent stakeholders from adopting behaviors that can both limit the introduction of new invasive species and decrease the impacts of those already established. The seven terms we propose are “native”, “nonnative”, “introduced”, “established”, “invasive”, “nuisance”, and “range change”. We also list six terms to avoid due to their tendency to create confusion and/or be misused and misinterpreted (“native invasive”, “invasive exotic”, “invasive weed”, “alien”, “foreign”, and “nonindigenous”) as well as precise definitions of common legal terms (“noxious weed”, “injurious”, “prohibited”, and “conditional/restricted”). By speaking this common language, Florida’s Extension and outreach professionals can deliver a simplified and unified message about the impacts of invasive species and how to best prevent and control them, potentially increasing the environmental and socioeconomic benefits of invasive species Extension and outreach programs.

Revealing the Introduction History and Phylogenetic Relationships of Passiflora foetida sensu lato in Australia

Genomic analysis can be a valuable tool to assistmanagement of non-native invasive species, through determining source and number of introductions as well as clarifying phylogenetic relationships. Here, we used whole chloroplast sequencing to investigate the introduction history of Passiflora foetida sensu lato in Australia and clarify its relationship with other Passiflora species present. Phylogenetic analysis of chloroplast genome data identified three separate genetic lineages of P. foetida s. l. present in Australia, indicating multiple introductions. These lineages had affinities to samples from three separate areas within the native range in Central and South America that represented phylogenetically distinct lineages. These results provide a basis for a targeted search of the native range of P. foetida s. l. for candidate biological control agents that have co-evolved with this species and are thus better adapted to the lineages that are present in Australia. Results also indicated that the Passiflora species native to Australia are in a separate clade to that of P. foetida s. l. and other introduced Passiflora species cultivated in Australia. This knowledge is important to assess the likelihood of finding biological control agents for P. foetida s. l. that will be sufficiently host-specific for introduction in Australia. As P. foetida s. l. is a widespread non-native invasive species across many regions of the world, outcomes from this work highlight the importance of first evaluating the specific entities present in a country before the initiation of a biological control program.

Management and Control Issues for Native, Invasive Species (Reed Canarygrass): Evaluating Philosophical, Management, and Legislative Issues

The issue of native invasive species management rarely occurs and is fraught with biological, social, and economic challenges as well as posing difficulties in decision-making for land managers. The terminology for categorization of invasive species is examined in the context of their bias(es), which complicates control. An example of a newly determined native species, which is also invasive, is used as an example to navigate control and regulatory issues. Native, invasive reed canarygrass (Phalaris arundinacea L.) occurs throughout Minnesota and most likely the entire midwest region of central United States and Canadian provinces. The species was previously assumed to be an exotic, nonnative Eurasian import but recent molecular evidence supports its status as a native but invasive species. We address how this change to being a native but highly invasive species modifies approaches to mitigate its potential control for state, Tribal, and local authorities. The implications of these new findings will require differential shifts in land managers’ perspectives and approaches for control. Particular differences may exist for Tribal Land Managers vs. departments of natural resources and private agencies. Additionally, regulatory challenges have yet to be decided on how to legislate control for a native invasive species that had been previously assumed as exotic or foreign in origin. These opportunities to change attitudes and implement judicial control measures will serve as a template for other invasive species that are native in origin.

Plant-Mediated Rhizosphere Oxygenation in the Native Invasive Salt Marsh Grass Elymus athericus

In the last decades, the spread of Elymus athericus has caused significant changes to the plant community composition and ecosystem services of European marshes. The distribution of E. athericus was typically limited by soil conditions characteristic for high marshes, such as low flooding frequency and high soil aeration. However, recently the spread of E. athericus has begun to also include low-marsh environments. A high-marsh ecotype and a low-marsh ecotype of E. athericus have been described, where the latter possess habitat-specific phenotypic traits facilitating a better adaption for inhabiting low-marsh areas. In this study, planar optodes were applied to investigate plant-mediated sediment oxygenation in E. athericus, which is a characteristic trait for marsh plants inhabiting frequently flooded environments. Under waterlogged conditions, oxygen (O2) was translocated from aboveground sources to the roots, where it leaked out into the surrounding sediment generating oxic root zones below the sediment surface. Oxic root zones were clearly visible in the optode images, and no differences were found in the O2-leaking capacity between ecotypes. Concentration profiles measured perpendicular to the roots revealed that the radius of the oxic root zones ranged from 0.5 to 2.6 mm measured from the root surface to the bulk anoxic sediment. The variation of oxic root zones was monitored over three consecutive light–dark cycles (12 h/12 h). The O2 concentration of the oxic root zones was markedly reduced in darkness, yet the sediment still remained oxic in the immediate vicinity of the roots. Increased stomatal conductance improving the access to atmospheric O2 as well as photosynthetic O2 production are likely factors facilitating the improved rhizosphere oxygenation during light exposure of the aboveground biomass. E. athericus’ capacity to oxygenate its rhizosphere is an inheritable trait that may facilitate its spread into low-marsh areas. Furthermore, this trait makes E. athericus a highly competitive species in marshes facing the effects of accelerated sea-level rise, where waterlogged sediment conditions could become increasingly pronounced.