Hidden dispersal in an urban world: genetic analysis reveals occasional long-distance dispersal and limited spatial substructure among Dutch pine martens

Fine-scale variation within urban landscapes affects marking patterns and gastrointestinal parasite diversity in red foxes

Urban areas are often considered to be a hostile environment for wildlife as they are highly fragmented and frequently disturbed. However, these same habitats can contain abundant resources, while lacking many common competitors and predators. The urban environment can have a direct impact on the species living there but can also have indirect effects on their parasites and pathogens. To date, relatively few studies have measured how fine-scale spatial heterogeneity within urban landscapes can affect parasite transmission and persistence.Here, we surveyed 237 greenspaces across the urban environment of Edinburgh (UK) to investigate how fine-scale variation in socio-economic and ecological variables can affect red fox (Vulpes vulpes) marking behavior, gastrointestinal (GI) parasite prevalence, and parasite community diversity.We found that the presence and abundance of red fox fecal markings were nonuniformly distributed across greenspaces and instead were dependent on the ecological characteristics of a site. Specifically, common foraging areas were left largely unmarked, which indicates that suitable resting and denning sites may be limiting factor in urban environments. In addition, the amount of greenspace around each site was positively correlated with overall GI parasite prevalence, species richness, and diversity, highlighting the importance of greenspace (a commonly used measure of landscape connectivity) in determining the composition of the parasite community in urban areas.Our results suggest that fine-scale variation within urban environments can be important for understanding the ecology of infectious diseases in urban wildlife and could have wider implication for the management of urban carnivores.

Sex-biased dispersal patterns of a social passerine: complementary approaches and evidence for a role of spatial scale

Animal dispersal patterns have important implications for many biological processes, but the measurement of dispersal is challenging and often requires the use of complementary approaches. In this study, we investigated the local-scale sex-biased dispersal pattern in a social bird, the black-throated tit (Aegithalos concinnus), in central China. Spatial genetic autocorrelation analyses suggested that significant fine-scale genetic structure existed in males but not in females. Mark–recapture analyses of ringed individuals also showed that female offspring were more dispersive than male offspring, supporting genetic evidence of local female-biased dispersal. These results were contrary to a previous finding of male-biased long-distance dispersal in this species that was based on analyses of gene flow across the species range in China. This implies that the species might potentially have a scale-dependent dispersal strategy, with females frequently dispersing further than males at the local level, but with a proportion of males occasionally dispersing over long distances and contributing more to gene flow at a larger geographical scale. Long-distance dispersal by male black-throated tits might be induced by competition for resources or by unfavourable environmental conditions, warranting further investigation, but our findings increase the evidence that geographical scale is an important factor to be considered when investigating animal dispersal patterns.

Outbreaks of canine distemper in Dutch and Belgian mink farms

Background: Vaccination of farmed minks against canine distemper virus (CDV) has proved to be very effective. In the Netherlands, vaccination of farmed minks against CDV was mandatory until the closure of the local agricultural product boards at the end of 2014.

Objectives: To describe the first documented outbreaks of CD in Dutch mink farms since the closure of the agricultural product boards, as well as an outbreak in Belgium, with special attention to genotyping of the isolates.

Methods: A full post-mortem was performed on three carcasses per submission from farms A–C and on two carcasses from farm D. Molecular detection with subsequent typing was performed on eleven samples originating from four different farms. To assess genetic diversity partial sequences of the H gene of CDV were compared based on phylogenetic analysis.

Results: In 2017, there was a sudden series of CD outbreaks affecting four mink farms in the Netherlands (A–C) and Belgium (D). Gross, histologic and immunohistochemical findings were similar. There was a degree of genetic similarity between the viruses on farms A and D (98.5%) and between the viruses on farms B and C (97.3%), but the viruses from farms A and D belonged to a different clade than the viruses from farms B and C. Higher mortalities were reported in white and pastel minks.

Conclusions: Findings indicated that the difference in severity of the outbreaks was partially related to the genetic composition of the farm populations. Vaccination against CDV on Dutch and Belgian mink farms seems warranted.

Genetic population structure of fishers (Pekania pennanti) in the Great Lakes region: remnants and reintroductions

Reintroduction programs have been pivotal in augmenting populations of fishers (Pekania pennanti (Erxleben, 1777)) and re-establishing them to their former range in North America. The majority of reintroduction efforts in fishers have been considered demographically successful, but reintroductions can alter genetic population structure and success has rarely been evaluated in fishers from a genetic standpoint. We used microsatellite data (n = 169) to examine genetic population structure of fishers in the Great Lakes region and comment on the success of past reintroductions at two different spatial scales. We found significant genetic population structure among source and reintroduced populations within the Great Lakes region and large-scale genetic structure between fisher populations located in two geographically distant regions (Great Lakes and Northeast) in the eastern United States. Reintroductions associated with the Great Lakes produced results that were largely consistent with other studies of fisher reintroductions in the Northeast. However, our data are the first to support a measurable impact on genetic population structure in Pekania pennanti pennanti (Erxleben, 1777) from a reintroduction using geographically distant source and reintroduced populations. When feasible, we strongly recommend that reintroduction programs include an investigation of the underlying genetic structure to better define intended goals and supplement measures of demographic success.

Long-Distance Dispersal after the Last Glacial Maximum (LGM) Led to the Disjunctive Distribution of Pedicularis kansuensis (Orobanchaceae) between the Qinghai-Tibetan Plateau and Tianshan Region

Quaternary climate fluctuations have profoundly affected the current distribution patterns and genetic structures of many plant and animal species in the Qinghai-Tibetan Plateau (QTP) and adjacent mountain ranges, e.g. Tianshan (TSR), Altay, etc. In this greater area disjunct distributions are prominent but have nevertheless received little attention with respect to the historical processes involved. Here, we focus on Pedicularis kansuensis to test whether the current QTP and TSR disjunction is the result of a recent Holocene range expansion involving dispersal across arid land bridge(s) or a Pleistocene range fragmentation involving persistence in refugia. Two chloroplast DNA spacers were sequenced for 319 individuals from 34 populations covering the entire distribution range of this species in China. We found a total of 17 haplotypes of which all occurred in the QTP, and only five in the TSR. Overall genetic diversity was high (H_T = 0.882, H_S = 0.559) and higher in the QTP than in the TSR. Genetic differentiation among regions and populations was relatively low (G_ST = 0.366) and little evidence for a phylogeographic pattern emerged. The divergence times for the four main lineages could be dated to the early Pleistocene. Surprisingly, the two ubiquitous haplotypes diverged just before or around the Last Glacial Maximum (LGM) and were found in different phylogenetic lineages. The Species Distribution Model suggested a disappearance of P. kansuensis from the TSR during the LGM in contrast to a relatively constant potential distribution in the QTP. We conclude that P. kansuensis colonized the TSR after the LGM. The improbable long-distance dispersal by wind or water across arid land seed flow may well have had birds or men as vector.