Natural landscape heterogeneity and barriers resulting from urbanization can reduce genetic connectivity between populations. The evolutionary, demographic, and ecological effects of reduced connectivity may lead to population isolation and ultimately extinction. Alteration to the terrestrial and aquatic environment caused by urban influence can affect gene flow, specifically for stream salamanders who depend on both landscapes for survival and reproduction. To examine how urbanization affects a relatively common stream salamander species, we compared genetic connectivity of Eurycea bislineata (northern two‐lined salamander) populations within and between streams in an urban, suburban, and rural habitat around the New York City (NYC) metropolitan area. We report reduced genetic connectivity between streams within the urban landscape found to correspond with potential barriers to gene flow, that is, areas with more dense urbanization (roadways, industrial buildings, and residential housing). The suburban populations also exhibited areas of reduced connectivity correlated with areas of greater human land use and greater connectivity within a preserve protected from development. Connectivity was relatively high among neighboring rural streams, but a major roadway corresponded with genetic breaks even though the habitat contained more connected green space overall. Despite greater human disturbance across the landscape, urban and suburban salamander populations maintained comparable levels of genetic diversity to their rural counterparts. Yet small effective population size in the urban habitats yielded a high probability of loss of heterozygosity due to genetic drift in the future. In conclusion, urbanization impacted connectivity among stream salamander populations where its continual influence may eventually hinder population persistence for this native species in urban habitats.

The status of the Fernandina Island Galapagos giant tortoise (Chelonoidis phantasticus) has been a mystery, with the species known from a single specimen collected in 1906. The discovery in 2019 of a female tortoise living on the island provided the opportunity to determine if the species lives on. By sequencing the genomes of both individuals and comparing them to all living species of Galapagos giant tortoises, here we show that the two known Fernandina tortoises are from the same lineage and distinct from all others. The whole genome phylogeny groups the Fernandina individuals within a monophyletic group containing all species with a saddleback carapace morphology and one semi-saddleback species. This grouping of the saddleback species is contrary to mitochondrial DNA phylogenies, which place the saddleback species across several clades. These results imply the continued existence of lineage long considered extinct, with a current known population size of a single individual.

No abstract

1Urbanization is an increasingly pervasive form of land transformation that reduces biodiversity 2 of many taxonomic groups. Beetles exhibit a broad range of responses to urbanization, likely due 3 to the high functional diversity in this order. Carrion beetles (Order: Coleoptera, Family: 4 Silphidae) provide an important ecosystem service by promoting decomposition of small-bodied 5 carcasses, and have previously been found to decline due to forest fragmentation caused by 6 urbanization. However, New York City (NYC) and many other cities have fairly large 7 continuous forest patches that support dense populations of small mammals, and thus may harbor 8 relatively robust carrion beetle communities in city parks. In this study, we investigated carrion 9 beetle community composition, abundance and diversity in forest patches along an urban-to-rural 10 gradient spanning the urban core (Central Park, NYC) to outlying rural areas. We conducted an 11 additional study focusing on comparing the current carrion beetle community at a single 12 suburban site in Westchester County, NY that was intensively surveyed in the early 1970's. We 13 collected a total of 2,170 carrion beetles from eight species at 13 sites along this gradient. We 14 report little to no effect of urbanization on carrion beetle diversity, although two species were not 15 detected in any urban parks. Nicrophorus tomentosus was the most abundant species at all sites 16 and seemed to dominate the urban communities, potentially due to its generalist habits and 17 shallower burying depth compared to the other beetles surveyed. Variation between species in 18 body size, habitat specialization, and % forest area also did not influence carrion beetle 19 communities. Lastly, we found few significant differences in relative abundance of 10 different 20

Galapagos giant tortoises are endemic to the Galapagos Archipelago, where they are found in isolated populations. While these populations are widely considered distinguishable in morphology, behavior, and genetics, the recent divergence of these taxa has made their status as species controversial. Here, we apply modern methods of species delimitation to whole genome resequencing data from 38 tortoises across all 13 extant taxa to assess support for delimiting these taxa as species. We find strong evidence to reject the hypothesis that all Galapagos giant tortoises belong to a single species. Instead, a conservative interpretation of model-based and divergence-based results indicates that these taxa form a species complex consisting of a minimum of 5 species, with some analyses supporting as many as 13 species. There is mixed support for the species status of taxa living on the same island, with some methods delimiting them as separate species and others suggesting there is a single species per island. These results make clear that Galapagos giant tortoise taxa represent different stages in the process of speciation, with some taxa further along in that evolutionary process than others. A better understanding of the more complex parts of that process is urgently needed, given the threatened status of Galapagos giant tortoises.