Genic introgression from an invasive exotic fungal forest pathogen increases the establishment potential of a sibling native pathogen

Significant hybridization between the invasive North American fungal plant pathogen Heterobasidion irregulare and its Eurasian sister species H. annosum is ongoing in Italy. Whole genomes of nine natural hybrids were sequenced, assembled and compared with those of three genotypes each of the two parental species. Genetic relationships among hybrids and their level of admixture were determined. A multi-approach pipeline was used to assign introgressed genomic blocks to each of the two species. Alleles that introgressed from H. irregulare to H. annosum were associated with pathways putatively related to saprobic processes, while alleles that introgressed from the native to the invasive species were mainly linked to gene regulation. There was no overlap of allele categories introgressed in the two directions. Phenotypic experiments documented a fitness increase in H. annosum genotypes characterized by introgression of alleles from the invasive species, supporting the hypothesis that hybridization results in putatively adaptive introgression. Conversely, introgression from the native into the exotic species appeared to be driven by selection on genes favoring genome stability. Since the introgression of specific alleles from the exotic H. irregulare into the native H. annosum increased the invasiveness of the latter species, we propose that two invasions may be co-occurring: the first one by genotypes of the exotic species, and the second one by alleles belonging to the exotic species. Given that H. irregulare represents a threat to European forests, monitoring programs need to track not only exotic genotypes in native forest stands, but also exotic alleles introgressed in native genotypes.

Warming impacts potential germination of non-native plants on the Antarctic Peninsula

The Antarctic Peninsula is under pressure from non-native plants and this risk is expected to increase under climate warming. Establishment and subsequent range expansion of non-native plants depend in part on germination ability under Antarctic conditions, but quantifying these processes has yet to receive detailed study. Viability testing and plant growth responses under simulated Antarctic soil surface conditions over an annual cycle show that 16 non-native species, including grasses, herbs, rushes and a succulent, germinated and continued development under a warming scenario. Thermal germination requirement (degree day sum) was calculated for each species and field soil-temperature recordings indicate that this is satisfied as far south as 72° S. Here, we show that the establishment potential of non-native species, in number and geographical range, is considerably greater than currently suggested by species distribution modelling approaches, with important implications for risk assessments of non-native species along the Antarctic Peninsula.

Natural regeneration of Pinus spp. around seed production areas and orchards

This study aims at determining the establishment potential of the main species of the Pinus genus planted in Brazil and broaden the knowledge on the conditions that facilitate the invasion. The density of regenerants neighboring pine stands planted with 35 populations of Pinus spp. (P. caribaea (var. bahamensis and var. caribaea), P. elliottii, P. kesiya, P. merkussi, P. oocarpa, P. patula, P. pseudstrobus, P. strobus, P. taeda, and P. tecunomanii) was evaluated in three locations in the state of São Paulo. The vegetal covers neighboring the pine stands were evaluated regarding native vegetation occupation, open area, and eucalypts plantation. The census of regenerants was conducted up to 100 m away from the pine stand edges; samples were collected over an area divided into four 25m-wide transects. In each transect, the regenerants were quantified and classified into three size classes: sprouts (≤ 0.3 m), seedlings (≥ 0.3 m ≤ 1.0 m), and trees (> 1.0 m). The results indicate that Pinus elliottii is the species with the greatest invasion potential in the studied areas since it adapts to different environments. Areas without established vegetation favored regeneration, indicating the effect of the environment on regeneration occurrence. The number of regenerants increased near the seed source but decreased significantly between 50 and 100 m away, despite the directional effect of the prevailing winds and the long-distance dispersal capacity of the genus.

Wave Modeling for the Establishment Potential Area of Offshore Aquaculture in Indonesia

Aquaculture is expected to further improve in the future and can provide 57 percent of fish for human consumption by 2025. In Indonesia, the aquaculture sector produced 5.77% of the world total production in 2014 and increases annually by, on average, 0.62%. Prigi Bay, located in the south of east Java, is one potential area to develop sustainable aquaculture in Indonesia. This study presents numerical wave modeling to investigate the potential area for offshore aquaculture in Prigi Bay. The method used Delft3D Flow and CG WAVE model to simulate wave and current. The superimposed analysis is used to select potential areas between the results of the model and the criteria of environmental parameters. The result shows that the location which meets the aquaculture criteria is located at coordinates 8.311° S–8.322° S and 111.734° E–111.747° E. This site has a depth of around 18–26 m with current velocity between 0.10 and 0.14 m/s and significant a wave height between 0.2–0.4 m. This location is the most suitable location for aquaculture in the Prigi Bay.

Predicting Establishment Potential of an Invasive Wood-Boring Beetle, Trichoferus campestris (Coleoptera: Cerambycidae) in the United States

Solid wood packaging material (WPM) is widely recognized as a high-risk pathway for transport and potential introduction of wood-boring insects, including longhorned beetles in the family Cerambycidae. These beetles also are occasionally imported in finished wood products, such as furniture and decorative items. A targeted effort to identify wood borers intercepted as larvae in WPM at U.S. ports between 2012 and 2018 revealed that one of the most frequently intercepted species was Trichoferus campestris (Faldermann), a cerambycid native to Asia. Trichoferus campestris is a pest of quarantine concern in the United States, Canada, and Europe. The establishment risk of this beetle in the United States is high because of its frequent introduction through multiple pathways and its potential to inhabit natural and urban forests as well as agricultural systems. In this study, we compiled port interception and detection data to examine risk based on historical introductions and pathways. We tested whether the intended destination of cargo intercepted with T. campestris-infested WPM can be used as a predictor of inland introductions, assuming that individuals of T. campestris are likely to be moved through established trade routes between export–import partners. We also developed maps to predict likely areas of introduction and establishment in the United States based on pathway analysis and climate suitability data. The maps will enable informed prioritization of resources in pest surveillance, and may serve as models for other wood borers identified in the WPM and wood products pathway.

Forecasting the potential distribution of the invasive vegetable leafminer using ‘top-down’ and ‘bottom-up’ models

The vegetable leafminer, Liriomyza sativae, is an internationally significant pest of vegetable and flower crops, that was detected for the first time on the Australian mainland in 2015. Due to the early stage of its invasion in Australia, it is unclear how climatic conditions are likely to support and potentially restrict the distribution of L. sativae as it expands into a novel range and threatens agricultural production regions. Here we predicted the future establishment potential of L. sativae in Australia, using both a novel ‘bottom-up’ process-based model and a popular ‘top-down’ correlative species distribution model (SDM), leveraging the unique strengths of each approach. Newly compiled global distribution data spanning 42 countries was used to validate the process-based model of establishment potential based on intrinsic population growth rates, as well as parameterise the correlative SDM. Both modelling approaches successfully captured the international distribution of L. sativae based on environmental variables and predicted the high suitability of non-occupied ranges, including northern regions of Australia. The largely unfilled climatic niche available to L. sativae in Australia demonstrates the early stage of its Australian invasion, and highlights locations where important vegetable and nursery production regions in Australia are highly vulnerable to L. sativae establishment.

Potential Invasion Risk of Pet Traded Lizards, Snakes, Crocodiles, and Tuatara in the EU on the Basis of a Risk Assessment Model (RAM) and Aquatic Species Invasiveness Screening Kit (AS-ISK)

Because biological invasions can cause many negative impacts, accurate predictions are necessary for implementing effective restrictions aimed at specific high-risk taxa. The pet trade in recent years became the most important pathway for the introduction of non-indigenous species of reptiles worldwide. Therefore, we decided to determine the most common species of lizards, snakes, and crocodiles traded as pets on the basis of market surveys in the Czech Republic, which is an export hub for ornamental animals in the European Union (EU). Subsequently, the establishment and invasion potential for the entire EU was determined for 308 species using proven risk assessment models (RAM, AS-ISK). Species with high establishment potential (determined by RAM) and at the same time with high potential to significantly harm native ecosystems (determined by AS-ISK) included the snakes Thamnophis sirtalis (Colubridae), Morelia spilota (Pythonidae) and also the lizards Tiliqua scincoides (Scincidae) and Intellagama lesueurii (Agamidae).

Investigating the probability of establishment of Zika virus and detection through mosquito surveillance under different temperature conditions

Because of the increasing threat that Zika virus (ZIKV) poses to extra-tropical regions due to increased global travel, there is a need for better understanding of the effect(s) of temperature on the establishment potential of ZIKV within these subtropical, temperate, and/or seasonal Ae. aegypti populations. The first step to determining risk establishment of ZIKV in these regions is to assess ZIKV’s ability to infect mosquitoes at less tropical temperatures, and thus be detected through common surveillance programs. To that end, the effect of two rearing temperatures (RT) and extrinsic incubation temperatures (EIT) on infection and dissemination rates was evaluated, as well as the interactions of such. Total, there were four combinations (RT24-EIT24, RT24-DEI28, RT28-EIT24, RT28- EIT28). Further, a stochastic SEIR framework was adapted to determine whether observed data could lead to differential success of establishment of ZIKV in naive mosquito populations. There was no consistent pattern in significant differences found across treatments for either infection or dissemination rates (p>0.05), where only a significant difference was found in infection rates between RT24- EIT24 (44%) and RT28-EIT24(82.6%). Across all temperature conditions, the model predicted between a 77.3% and 93.1% chance of successful establishment of ZIKV in naive mosquito populations under model assumptions. Further, the model predicted between 4.1% and 46.7% chance of at least one mosquito developing a disseminated infection, depending on temperature conditions, despite no significant differences in the experimental data. These results indicate that 1) there is no straightforward relationship between RT, EIT, and infection/dissemination rates for ZIKV, similar to what has been reported for DENV, 2) in more temperate climates, ZIKV may still have the ability to establish in populations of Ae. aegypti, and 3) despite a lack of statistical differences in observed experimental data, model predictions indicate that the interplay of rearing and extrinsic incubation temperatures may still alter the kinetics of ZIKV within the mosquito enough to affect numbers of infected/disseminated mosquitoes and the associated probability of detection through surveillance programs.