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Strychnine is a neurotoxin and an active ingredient in some rodenticides which are placed in burrows to suppress pocket gopher (Thomomys talpoides) populations in range and crop land in western North America. The population level impact was modelled of the use of strychnine-based rodenticides on a non-target snake species, the Great Basin Gophersnake (Pituophis catenifer deserticola), which is a predator of pocket gopher and a Species at Risk in Canada. Using information on population density, demographics, and movement and habitat suitability for the Gophersnake living in an agricultural valley in BC, Canada, we estimated the impact of the poisoning of adult snakes on the long-term population size. To determine the area where Gophersnakes could be exposed to strychnine, we used vendor records of a rodenticide, and quantified the landcover areas of orchards and vineyards where the compound was most commonly applied. GIS analysis determined the areas of overlap between those agricultural lands and suitable habitats used by Gophersnakes. Stage-based population matrix models revealed that in a low density (0.1/ha) population scenario, a diet of one pocket gopher per year wherein 10 % of them carried enough strychnine to kill an adult snake could cause the loss of 2 females annually from the population and this would reduce the population by 35.3 % in 25 years. Under the same dietary exposure, up to 35 females could die per year in a high density (0.4/ha) population which would result in a loss of 50 % of adults in 25 years.

A quantitative, probabilistic approach to species and population assessment can be used to inform a species' legal at-risk designation and help determine priorities and targets for population recovery and protection measures. To that aim, we analysed the viability of a large number of individual populations of a species across its range in Canada, we compared that viability among populations, and we assess the viability of all those populations as a whole. We used Pitcher's thistle, Cirsium pitcheri, as a case because it is listed at risk in both Canada and the United States but its actual risk of extinction remains unclear. Also, for this monocarpic plant endemic to Great Lakes dunes and beaches, there are 35 years of monitoring data available for the populations in Pukaskwa National Park on Lake Superior, and nearly 17 years of data for populations on Lake Huron. Means and variances of the annual population growth rates were computed from those time series, to estimate the cumulative distribution function for time-to-extinction, using the diffusion approximation as well as simulations. We also ran multi-population stochastic projections to estimate the risk of decline of the whole Canadian population. We found that many Pitcher's thistle populations have a high probability of either extinction or undergoing a 50% decline at some point in their future. This is due mainly to steady declines experienced by small populations. However, multi-population stochastic projections and the projected growth of many large individual populations indicate that Pitcher's thistle is likely to persist in Canada over the next 100 years, assuming past conditions continue in the future. Keywords: Viability analysis, Species at risk, Species status assessment, Pitcher thistle, Plant population dynamics, Environmental variation, Endemic species

The distribution and abundance of woodland caribou (Rangifer tarandus caribou) have declined dramatically in the past century. Without intervention the most southern population of caribou in eastern North America is expected to disappear within 20 years. Although translocations have reintroduced and reinforced some populations, approximately half of caribou translocation efforts fail. Translocations are resource intensive and risky, and multiple interrelated factors must be considered to assess their potential for success. Structured decision-making tools, such as Bayesian belief networks, provide objective methods to assess different wildlife management scenarios by identifying the key components and relationships in an ecosystem. They can also catalyze dialogue with stakeholders and provide a record of the complex thought processes used in reaching a decision. We developed a Bayesian belief network for a proposed translocation of woodland caribou into a national park on the northeastern coast of Lake Superior, Ontario, Canada. We tested scenarios with favourable (e.g., good physical condition of adult caribou) and unfavourable (e.g., high predator densities) conditions with low, medium, and high numbers of translocated caribou. Under the current conditions at Pukaskwa National Park, augmenting the caribou population is unlikely to recover the species unless wolf densities remain low (

Aim The objectives of this study were: (1) to compare radial growth patterns between white oak (Quercus alba L.) and northern red oak (Quercus rubra L.) growing at the northern distribution limit of white oak; and (2) to assess if the radial growth of white oak at its northern distribution limit is controlled by cold temperature. Location The study was conducted in three regions of the Ottawa valley in southern Quebec. All stands selected were located at the northern limit of distribution of Q. alba. Methods Twelve mixed red and white oak stands were sampled and increment cores were extracted for radial growth analyses. For each oak species, 12 chronologies were derived from tree-ring measurement (residual chronologies). Principal components analysis and redundancy analysis were used to highlight the difference between radial growth in both species and to determine their radial growth-climate association. Results There was little difference between the radial growth of each species; Q. alba, however, exhibits more year-to-year variation in growth than Q. rubra. More than 65% of the variance in radial growth was shared among sites and species. Both species showed a similar response to climate, which suggested that the limit of distribution of Q. alba might not be determined by effects on growth. Both species had a classic response to climate and drought in the early growing season. Main conclusions The northern distribution limit of Q. alba does not appear to be directly controlled by effects on growth processes as indicated by the similarities in radial growth and response to climate between the two species. The location of the stands on southern aspects suggested that cold temperature could have been a major factor controlling the distribution limit of Q. alba. However, it is speculated that stands growing on southern aspects may be more prone to forest fires or to drought, which would favour the maintenance and establishment of oaks, and of Q. alba in particular. Models relating the northern distribution limits of species to broad climate parameters like annual mean temperature will need to be reviewed to incorporate more biologically relevant information. Such assessments will in turn provide better estimates of the effect of climate changes on species distribution.

Goldenseal ( Hydrastis canadensis ) is a North American perennial clonal herb highly prized for its medicinal value. It is threatened at the northern range limit with only 20 populations known in Canada. To assist recovery planning, 13 populations were sampled to model dynamics. The fate of all ramets in one square-meter was monitored from 1998 to 2001. Transition matrices were built for 2000–2001, using three stage classes based on size and reproductive status. A six-stage pooled matrix, separating established ramets from newly produced ramets, was also constructed. Recruitment by seed was not observed and therefore excluded. The average population growth rate ( λ ) was 1.062 ± 0.053, which did not significantly differ from the equilibrium value (1.0) suggesting that the northern population is stationary. However, growth rates among population samples varied largely and had wide confidence intervals. Populations with λ -values less than or close to 1.0 require environmental change to increase. Recovery of goldenseal, and possibly other woodland perennials at risk, requires intervention aimed at population size augmentation, habitat optimization, and targeted dispersal.

The prevalence of secondary forests is increasing across tropical landscapes, but the effects of these environments on the population dynamics of understory species and on their capacity to regenerate after harvest remains poorly documented. We compare the population dynamics of the understory bromeliad, Aechmea magdalenae, between old-growth and secondary rainforests in Southeast Mexico. A. magdalenae is a non-timber forest product (NTFP), the ramets of which are harvested from wild populations to make forest plantations. The fates of 600 rosettes in the two forest types were monitored over 3 years to build annual transition matrices. Population projections using the matrices show that secondary forest populations have finite rates of growth significantly higher than those of old-growth populations under both ramet-harvest and no-harvest conditions. Life table response experiments indicate that differences in the capacity for re-growth after harvest was due to greater vegetative reproduction of the largest secondary forest rosettes and faster growth of their ramets. For understory NTFP such as A. magdalenae, secondary forests may offer more economic incentive and greater potential for forest conservation than old-growth forests.

Successful conservation of nontimberproducts and their rainforest habitats requires the identifica- tion of optimal harvest regimes, the accurate estimation of maximum harvest limits, and the implementation of those limits by local harvesters. We used a combination of participatory research techniques and demo- graphic modeling to determine maximum sustainable harvest rates of the bromeliad Aechmea magdalenae in the buffer zone of the Los Tuxtlas Biosphere Reserve in Mexico. We examined the effects of three types of vari- ation on maximum harvest rates: variation between forest types, between harvest regimes, and over time. We also tested the accuracy of estimating maximum harvest limits using matrix-model projections of unhar- vested populations. Maximum harvest rates of ramets from secondary forest populations were much higher than from primary-forest populations. Likewise, variation in local harvest regimes had a large effect on max- imum harvest rates. Populations concurrently harvestedfor leaves and ramets had higher maximum sustain- able levels of ramet harvest than those harvested for ramets only. Simulations using harvested and unhar- vested populations yielded significantly different estimates of maximum sustainable harvest limits, indicating that methods for calculating maximum harvest limits that assume linear responses to harvest may lead to er- roneous conclusions. Active participation in the research process enabled local harvesters to accept as valid the harvest limits determined in this study, to switch to using a more sustainable harvest regime, and to pass a local law prohibiting the destruction of their remaining primary forest because of its potential as A. magdale- nae habitat.

Summary 1 The clonal perennial herb Helianthus divaricatus and the clonal shrub Rhus aromatica reach the northern limit of their distribution in southern Quebec (Canada), where both are rare, but they are more common southwards in the adjacent province of Ontario. We tested whether peripheral populations of these species maintain themselves by having highly variable individual growth and survival rates. Their annual rates of population growth, λ, would then vary more, from year to year, than those of more southern populations in neighbouring Ontario, where the species are common. 2 Demographic analyses compared, over two transition intervals, size-based transition matrices for two northern (Gatineau Park, southern Quebec) and two southern populations (Pinery Park, southern Ontario) of each species. Comparisons used log-linear analyses, bias-corrected λ-values with 95% confidence intervals, and elasticity values. 3 For both species, the northern populations showed a larger variation between transition intervals and local populations in some of their vital rates and in λ-values. For H. divaricatus, elasticity values combined with log-linear analyses indicated that differences in the growth and survival of medium-sized ramets contributed most to the differences in λ-values between northern and southern populations. For R. aromatica, they indicated that differences in the fate of both medium and large ramets contributed to variation in λ. 4 Most of our data indicated a greater demographic variability in the northern populations of H. divaricatus and R. aromatica. At the northern periphery, these species grow in very few of the numerous habitat patches that appear to be suitable for them, whereas the two species together present a near continuous cover in all suitable habitats further south. High demographic variability therefore appears to contribute to determining the distribution of plant species, by increasing the extinction probabilities of local populations at the distribution limit.

On the west coast of Newfoundland (Canada) about 40% of the provincially rare plant species are not protected within the system of three national parks and two ecological reserves existing in the region. This study examines how heuristic algorithms can be used for selecting areas filling this gap while minimizing potential land use conflicts. One algorithm selected 78 areas of 1 km 2 each, representing the minimum set of areas that includes all species at least once. Only 13 out of these 78 areas were selected from existing protected areas; therefore, 65 would have to be added to this system to achieve full representation. A second algorithm reduced this number to 55 by seeking, from the beginning, only species not included in existing protected areas. A third algorithm constrained the choice of complementary areas to those that would have the lowest potential for conflicting land use (CLU). With this algorithm, however, full representation of rare plants within protected areas would need 79 areas instead of 55, i.e. trying to minimize the number of potentially conflicting areas entails selecting a significantly larger number of areas to achieve the same conservation goal. An index such as the CLU proposed here adds to the value of heuristic selection algorithms as indicative tools for planning a network of protected areas.

Many populations of threatened American ginseng (Panax quinquefolium) and vulnerable wild leek (Allium tricoccum) have declined and gone extinct because of overharvesting in Canada. We assessed the impact of harvesting on populations of these species in stochastically varying environments and estimated their extinction thresholds and minimum viable populations. With both species we used four transition ma- trices taken from the literature in stochastic population projections under various harvesting regimes. For American gingseng the mean population growth rate (A) declined with increasing harvesting rate (h) accord- ing to the number of years between harvests (tr), as -0.54 h tr0-( 909. When plants with more than two leaves are harvested every 5 years, a harvest rate of approximately 30% was sufficient to bring the A below the equi- librium value of 1.0. Extinction thresholds, the minimum number of plants needed to rebuild a population, varied from 30 to 90 plants, and the minimum viable population size was estimated at 170 plants. Only a dozen populations known in Canada exceed 170 plants, so most populations could not support any harvest- ing without serious threats to their long-term persistence. For wild leek, two harvesting strategies were identi- fied from confiscated, illegal harvests from Gatineau Park (Quebec): (1) "cboosy" harvesters collect fewer but larger bulbs, and (2) "busy" harvesters collect numerous but smaller bulbs. These data allowed simulations of more-realistic harvesting strategies. The rate of the decline A along the harvest gradient was faster for wild leek than for ginseng and varied with harvesting strategies. At harvesting rates between I and 8% the proba- bility that A falls below the equilibrium value was less than 5%. The extinction threshold of wild leek was esti- mated at 140-480 plants and the minimum viable population at 300-1030 plants, according to the threshold

Anticipating the effects of climate change on biodiversity is now critical for managing wild species and ecosystems. Climate change is a global driver and thus affects biodiversity globally. However, land-use planners and natural resource managers need regional or even local predictions. This provides scientists with formidable challenges given the poor documentation of biodiversity and its complex relationships with climate. We are approaching this problem in Quebec, Canada, through the CC-Bio Project (http://cc‑bio.uqar.ca/), using a boundary organization as a catalyst for team work involving climate modelers, biologists, naturalists, and biodiversity managers. In this paper we present the CC-Bio Project and its general approach, some preliminary results, the emerging hypothesis of the northern biodiversity paradox (a potential increase of biodiversity in northern ecosystems due to climate change), and an early assessment of the conservation implications generated by our team work.

L’agastache faux-népéta (Agastache nepetoides) est une plante vivace herbacée remarquable par sa hauteur qui peut dépasser 2 mètres. Elle pousse dans des milieux semi-ouverts, sur des sols calcaires, dans la grande région de Montréal. Sa situation est actuellement très précaire au Québec, et la population locale au parc national d’Oka serait la seule de taille viable. Des inventaires réalisés de 2010 à 2020 ont permis d’établir que cette population comprend 6 occurrences ou groupes d’individus occupant chacun une aire distincte, dont 2 disparues et 2 de découverte récente. Le suivi de plantes marquées dans 2 occurrences a révélé que cette espèce croît rapidement, fleurit, puis meurt après 3-4 ans. Le nombre d’individus fluctue grandement dans le temps, reflétant le cycle de vie court de l’espèce et son lien avec des conditions écologiques éphémères. Des projections démographiques sur 20 ans indiquent que les 2 occurrences sont vulnérables à long terme. Pour assurer la pérennité de l’espèce au parc, nous proposons 3 mesures d’atténuation des menaces : i) maintenir des habitats semi-ouverts ; ii) maintenir au moins 200 individus au sein du parc, répartis dans au moins 3 occurrences ; iii) propager l’espèce dans les habitats propices du secteur de la Grande Baie., The yellow giant hyssop (Agastache nepetoides) is an impressive herbaceous perennial plant that can reach over 2 metres in height. In the Greater Montréal region (Québec, Canada), it grows on calcareous soils in semi-open habitats. This species is likely to be designated threatened or vulnerable in Québec, and the local population in the Oka National Park appears to be the only one of a viable size. Surveys conducted from 2010 to 2020 identified 6 occurrences (well-delimited groups of individuals). Two of these disappeared over this period and 2 were newly discovered. Our monitoring of marked plants in 2 of the occurrences showed that the species grows fast, flowers, and dies after 3-4 years. The number of individuals fluctuated greatly over time, reflecting the short life cycle of the species and its association with ephemeral ecological conditions. Twenty-year population projections for the 2 monitored occurrences indicate that in the long-term, they are vulnerable. Three threat mitigation measures are proposed to ensure the survival of the species in the park: i) maintain semi-open habitat, ii) maintain at least 200 individuals distributed among at least 3 occurrences, and iii) introduce the species to suitable habitat in the Grande Baie sector.