Papers by BRUCE DIEGO CRUZ RODRIGUES
Inferences about sources and routes of colonization are important to understanding and managing i... more Inferences about sources and routes of colonization are important to understanding and managing introduced species. The Southern Red-backed Vole (SRBV; Myodes gapperi), not native to Newfoundland, was recently discovered in the western interior of the island, and its range is rapidly expanding. Theories regarding the origin of these animals include migration from an earlier release on a small coastal island, accompaniment of pulpwood imports, or an unsanctioned release as part of Newfoundland Marten (Martes americana atrata) recovery efforts. To determine the source, route, and potential timing of introduction to the island, we analyzed mitochondrial control-region sequences of 155 animals from Newfoundland and the two most likely sources, Cape Breton and Labrador. Although Cape Breton and Labrador contain phylogenetically distinct suites of haplotypes, both regions are part of the "eastern" clade of SRBV, indicating that the northeastern-most part of the range was recolonized from an eastern forest refugial lineage isolated during the Pleistocene. The Newfoundland population of SRBV contained only two haplotypes, one found in 89 individuals from multiple sampling locations that clusters with the Cape Breton subclade, and the other found in three individuals from Mine Pond and five from Labrador. We conclude that there have been at least two introductions to the island, with the Cape Breton-sourced introduction occurring earlier than the Labrador event; low diversity is consistent with recent timing of these events. Success of introduced voles in Newfoundland, despite little genetic diversity, probably reflects an exploitable niche for a broadly adapted boreal small mammal.
Viruses, 2021
The genus Protoparvovirus (family Parvoviridae) includes several viruses of carnivores. We descri... more The genus Protoparvovirus (family Parvoviridae) includes several viruses of carnivores. We describe a novel fox protoparvovirus, which we named Newlavirus as it was discovered in samples from Newfoundland and Labrador, Canada. Analysis of the full non-structural protein (NS1) sequence indicates that this virus is a previously uncharacterized species. Newlavirus showed high prevalence in foxes from both the mainland (Labrador, 54/137, 39.4%) and the island of Newfoundland (22/50, 44%) but was not detected in samples from other carnivores, including coyotes (n = 92), lynx (n = 58), martens (n = 146), mink (n = 47), ermines (n = 17), dogs (n = 48), and ringed (n = 4), harp (n = 6), bearded (n = 6), and harbor (n = 2) seals. Newlavirus was found at similar rates in stool and spleen (24/80, 30% vs. 59/152, 38.8%, p = 0.2) but at lower rates in lymph nodes (2/37, 5.4%, p < 0.01). Sequencing a fragment of approximately 750 nt of the capsid protein gene from 53 samples showed a high freq...
Gammaherpesviruses (GHVs) infect many animal species and are associated with lymphoproliferative ... more Gammaherpesviruses (GHVs) infect many animal species and are associated with lymphoproliferative disorders in some. Previously, we identified several novel GHVs in North American felids, however a GHV had never been identified in Canada lynx (Lynx canadensis). We therefore hypothesized the existence of an unidentified GHV in lynx. Using degenerate nested and subsequently virus-specific PCR, we amplified and sequenced 3.4 kb of DNA from a novel GHV in lynx, which we namedLynx canadensisgammaherpesvirus 1 (LcaGHV1). We then estimated the prevalence of LcaGHV1 in lynx by developing a PCR-based assay and detected LcaGHV1 DNA in 36% (95% CI: 22-53%) of lynx spleen DNA samples from Maine, USA and 17% (95% CI: 8-31%) from Newfoundland, Canada. Phylogenetic analysis determined that LcaGHV1 is a distinct GHV species belonging to the genusPercavirus. The potential ecologic and pathologic consequences of this novel virus for Canada lynx populations warrant further study.
Infection, Genetics and Evolution, 2017
Avian Conservation and Ecology, 2015
Across North America, Bald Eagle (Haliaeetus leucocephalus) populations appear to be recovering f... more Across North America, Bald Eagle (Haliaeetus leucocephalus) populations appear to be recovering following bans of DDT. A limited number of studies from across North America have recorded a surplus of nonbreeding adult Bald Eagles in dense populations when optimal habitat and food become limited. Placentia Bay, Newfoundland is one of these. The area has one of the highest densities of Bald Eagles in eastern North America, and has recently experienced an increase in the proportion of nonbreeding adults within the population. We tested whether the observed Bald Eagle population trends in Placentia Bay, Newfoundland during the breeding seasons 1990-2009 are due to habitat saturation. We found no significant differences in habitat or food resource characteristics between occupied territories and pseudo-absence data or between nest sites with high vs. low nest activity/occupancy rates. Therefore there is no evidence for habitat saturation for Bald Eagles in Placentia Bay and alternative hypotheses for the high proportion of nonbreeding adults should be considered. The Newfoundland population provides an interesting case for examination because it did not historically appear to be affected by pollution. An understanding of Bald Eagle population dynamics in a relatively pristine area with a high density can be informative for restoration and conservation of Bald Eagle populations elsewhere. Hausse de la population de Pygargue à tête blanche (Haliaeetus leucocephalus) dans la baie de Placentia, Terre-Neuve : indice de la saturation de l'habitat? RÉSUMÉ. Partout en Amérique du Nord, les populations de Pygargue à tête blanche (Haliaeetus leucocephalus) semblent se remettre à la suite de l'interdiction d'utilisation du DDT. Selon certaines recherches menées en Amérique du Nord, un surplus de pygargues adultes non nicheurs a été observé lorsque la densité des populations est élevée et que les conditions optimales d'habitat et de ressources alimentaires deviennent limitantes. La baie de Placentia, à Terre-Neuve, présente une telle situation : elle est l'hôte d'une densité de pygargues parmi les plus élevées de l'est de l'Amérique du Nord et a récemment connu une hausse du nombre d'adultes non nicheurs dans la population. Nous avons examiné si la saturation de l'habitat pouvait expliquer la tendance de la population de pygargues dans la baie de Placentia au cours des saisons de nidification de 1990 à 2009. Aucune différence significative des caractéristiques de l'habitat ou des ressources alimentaires n'a été observée entre les territoires occupés et ceux apparemment inoccupés, ni entre les sites de nidification montrant une forte activité de nidification/taux d'occupation et ceux en montrant une faible. Ainsi, il n'y a pas de preuve de saturation de l'habitat des pygargues dans la baie de Placentia, de sorte que d'autres hypothèses pouvant expliquer cette forte proportion d'adultes non nicheurs devraient être considérées. La population de Terre-Neuve représente un cas intéressant à examiner parce qu'elle n'aurait pas été affectée par la pollution ayant eu cours dans le passé. La compréhension de la dynamique de population des pygargues dans une région relativement vierge et hôte d'une densité élevée peut contribuer à la restauration et à la conservation des populations de pygargues ailleurs dans l'aire de reproduction.
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Papers by BRUCE DIEGO CRUZ RODRIGUES