Hugh Cross

Summary: Global change is reshaping Earth's biodiversity, but the changing distributions of nonpathogenic fungi remain largely undocumented, as do mechanisms enabling invasions. The ectomycorrhizal Amanita phalloides is native to Europe and invasive in North America. Using population genetics and genomics, we sought to describe the life history traits of this successfully invading symbiotic fungus. To test whether death caps spread underground using hyphae, or aboveground using sexual spores, we mapped and genotyped mushrooms from European and US sites. Larger genetic individuals (genets) would suggest spread mediated by vegetative growth, while many small genets would suggest dispersal mediated by spores. To test whether genets are ephemeral or persistent, we also sampled from populations over time. At nearly every site and across all time points, mushrooms resolve into small genets. Individuals frequently establish from sexual spores. But at one Californian site, a single individual measuring nearly 10 m across dominated. At two Californian sites, the same genetic individuals were discovered in 2004, 2014, and 2015, suggesting single individuals (both large and small) can reproduce repeatedly over relatively long timescales. A flexible life history strategy combining both mycelial growth and spore dispersal appears to underpin the invasion of this deadly perennial ectomycorrhizal fungus.

Environmental DNA (eDNA) metabarcoding has shown great promise as an effective, non‐invasive monitoring method for marine biomes. However, long filtration times and the need for state‐of‐the‐art laboratories are restricting sample replication and in situ species detections. Methodological innovations, such as passive filtration and self‐contained DNA extraction protocols, have the potential to alleviate these issues. We explored the implementation of passive sampling and a self‐contained DNA extraction protocol by comparing fish diversity obtained from active filtration (1 L; 0.45 μm cellulose nitrate [CN] filters) to five passive substrates, including 0.45 μm CN filters, 5 μm nylon filters, 0.45 μm positively charged nylon filters, artificial sponges, and fishing net. Fish diversity was then compared between the PDQeX Nucleic Acid Extractor and the conventional Qiagen DNeasy Blood & Tissue protocol. Experiments were conducted in both a controlled mesocosm and in situ at the Portobello Marine Laboratory, New Zealand. No significant differences in fish diversity were observed among active filtration and more porous passive materials (artificial sponges and fishing net) for both the mesocosm and harbor waters. For the in situ comparison, all passive filter membranes detected a significantly lower number of fish species, resulting from partial sample drop‐out. While no significant differences in fish eDNA signal diversity were observed between either DNA extraction methods in the mesocosm, the PDQeX system was less effective at detecting fish for the in situ comparison. Our results demonstrate that a passive sampling approach using porous substrates can be effectively implemented to capture eDNA from seawater, eliminating vacuum filtration processing. The large variation in efficiency observed among the five substrate types, however, warrants further optimization of the passive sampling approach for routine eDNA applications. The PDQeX system can extract high‐abundance DNA in a mesocosm with further optimization to detect low‐abundance eDNA from the marine environment.

The marbled polecat, Vormela peregusna, is one of the least studied species in the Mustelidae family, especially with regard to phylogeography and genetic diversity. In this study, we determined the mitochondrial genome sequence of V. peregusna and investigated its position within the Mustelidae phylogeny. The generated mitogenome is 15,982 bp in length; it consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region.

The Caucasian Squirrel, Sciurus anomalus, is the only representative of the Sciuridae family in the Eastern Mediterranean region. In this study, the mitochondrial genome of the Sciurus anomalus species was generated, and we investigate its phylogenetic position within the Sciuridae family. The generated mitogenome sequence is 16,234 bp. It is composed of a control region and a conserved set of 37 genes containing 13 protein-coding genes, 22 tRNA genes and 2 rRNA genes.

Genetic swamping resulting from interspecific hybridisation can increase extinction risk for threatened species. The development of high-throughput and reduced-representation genomic sequencing and analyses to generate large numbers of high resolution genomic markers has the potential to reveal introgression previously undetected using small numbers of genetic markers. However, few studies to date have implemented genomic tools to assess the extent of interspecific hybridisation in threatened species. Here we investigate the utility of genome-wide single nucleotide polymorphisms (SNPs) to detect introgression resulting from past interspecific hybridisation in one of the world’s rarest birds. Anthropogenic impacts have resulted in hybridisation and subsequent backcrossing of the critically endangered Aotearoa New Zealand endemic kakī (black stilts; Himantopus novaezelandiae ) with the non-threatened self-introduced congeneric poaka (Aotearoa New Zealand population of pied stilts, Himantopus himantopus leucocephalus ), yet genetic analyses with a limited set of microsatellite markers revealed no evidence of introgression of poaka genetic material in kakī, excluding one individual. We use genomic data for ∼63% of the wild adult kakī population to reassess the extent of introgression resulting from hybridisation between kakī and poaka. Consistent with previous genetic analyses, we detected no introgression from poaka into kakī. These collective results indicate that, for kakī, existing microsatellite markers provide a robust, cost-effective approach to detect cryptic hybrids. Further, for well-differentiated species, the use of genomic markers may not be required to detect admixed individuals.