Evidence for low genetic diversity and metapopulation structure in Canada yew (&lt;i&gt;Ta×us canadensis&lt;/i&gt;): considerations for conservation

Senneville, Sauphie; Beaulieu, J. P.; Daoust, Gaëtan; Deslauriers, Marie; Bousquet, Jean

doi:10.1139/cjfr-31-1-110

Cited by 10 publications

(2 citation statements)

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“…An exclosure study in the same system also revealed that protected T. canadensis produced more male and female strobili than individuals outside of exclosures, but significant differences were not seen until the fourth year of protection (Allison 1990a). Although sexual reproduction is important for the exchange of genetic material, this species appears to maintain its populations locally through vegetative propagation rather than seed dispersal (Senneville et al 2001). Taxus canadensis reproduces vegetatively through layering (Allison 1990a); therefore, it is likely that this process is also being negatively impacted by deer.…”

Section: Discussionmentioning

confidence: 90%

“…However, some understory shrubs such as the conifer Taxus canadensis Marsh., commonly known as Canada yew or ground hemlock, appear to lack any apparent resistance to ungulate browsers. Despite the presence of the toxin paclitaxel in its foliage (Senneville et al 2001), this shrub is favored browse for white-tailed deer (Odocoileus virginiana Zimmermann) in winter and for moose (Alces alces americana Clinton) year-round (Martell 1974).…”

Section: Introductionmentioning

confidence: 99%

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Death and Taxus: the high cost of palatability for a declining evergreen shrub, Taxus canadensis

et al. 2009

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Taxus canadensis Marsh., a shade-tolerant evergreen shrub, is in decline as a result of past anthropogenic disturbances and increased cervid browsing. To identify factors that may be influencing establishment for this species, we planted 1080 T. canadensis cuttings in a hemlock–hardwood forest in the spring of 2004. Cuttings were planted across a gradient of light environments, consisting of artificial canopy gaps (61–441 m2) and closed-canopy conditions, and half were protected with deer exclosures. Following four growing seasons, T. canadensis survival in exclosures was 92% compared with 75% in controls. A mixed-effects binary logistic regression analysis revealed that deer exclusion had the most influence on the probability of survival; all else being equal an individual was nearly seven times more likely to survive if planted inside an exclosure (P < 0.001). Increasing light intensity had a counterbalancing effect on growth and survival; light increased leader growth (P = 0.019) but reduced an individual’s probability of survival (P < 0.001), possibly owing to enhanced herbivory and elevated moisture stress. Consequently, enhancing resource availability and growth may not decrease the impact of biomass loss to herbivory. These results suggest that even with relatively low herbivore densities, exclosures are required for the recovery of highly palatable species.

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Section: Discussionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Death and Taxus: the high cost of palatability for a declining evergreen shrub, Taxus canadensis

et al. 2009

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Spatial genetic structure of Taxus baccata L. in the western Mediterranean Basin: Past and present limits to gene movement over a broad geographic scale

González‐Martínez

Dubreuil²,

Riba³

et al. 2010

Molecular Phylogenetics and Evolution

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Genetic Diversity, Population Structure, and Conservation of Sophora moorcroftiana (Fabaceae), a Shrub Endemic to the Tibetan Plateau

et al. 2006

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Sophora moorcroftiana is a perennial leguminous low shrub endemic to the middle reaches of Yarlung Zangbo River in Tibet. It is an important species to fix sand dunes and to avoid the formation of shifting sands; therefore, its progressive over-exploitation may enhance land desertification. The levels and distribution of genetic variability of this species were evaluated from 10 natural populations at 24 loci encoding 13 enzymes, using allozyme analysis by starch gel electrophoresis. Data obtained revealed moderate levels of genetic variation within populations (Pp=27.5%, Ap=1.5, Hep=0.122) and a considerable divergence among populations (FST=0.199). Significant positive correlations (r2=0.49, p<0.05; r2=0.46, p<0.05) were found between elevation and both mean number of alleles per locus (A) and gene diversity (He) in the studied populations of S. moorcroftiana. Lower genetic diversity in lower elevation populations might be due to the negative effects of human pressures and habitat fragmentation, to adaptation to high altitudes as a consequence of a peripatric speciation process, or to directional gene flow along the river basin from the source populations located in the west at higher altitudes. The evaluation of the degree of threat has led to the inclusion of this species in the category of EN ("endangered"), and conservation strategies for this endemic species are discussed on the basis of these findings.

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Evidence for low genetic diversity and metapopulation structure in Canada yew (<i>Ta×us canadensis</i>): considerations for conservation

Cited by 10 publications

References 0 publications

Death and Taxus: the high cost of palatability for a declining evergreen shrub, Taxus canadensis

Death and Taxus: the high cost of palatability for a declining evergreen shrub, Taxus canadensis

Spatial genetic structure of Taxus baccata L. in the western Mediterranean Basin: Past and present limits to gene movement over a broad geographic scale

Genetic Diversity, Population Structure, and Conservation of Sophora moorcroftiana (Fabaceae), a Shrub Endemic to the Tibetan Plateau

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