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Alternative successional trajectories (AST) may result in multiple climax states within an ecosystem when disturbances affect colonization history. In the boreal forest, ungulates have been proposed to drive AST because, under herbivore pressure, preferred species may go extinct and apparent competition may benefit browsing-resistant species. Over a 15-year period following logging, we tested whether deer herbivory altered plant species composition and whether the competitive advantage of resistant species was maintained following herbivore removal. We compared exclosures built immediately after logging with delayed exclosures built eight years later on Anticosti Island, Quebec, Canada. Although the palatable tree Betula papyrifera (paper birch) and some palatable herbs recovered in delayed exclosures, we observed legacies in both tree and herb cover. Woody regeneration in delayed exclosures was dominated by Picea glauca (white spruce), and Poaceae (grasses) were abundant in the field layer. Given that only early-successional species recovered, whereas late-successional broadleaf species and Abies balsamea (balsam fir) remained rare, succession may follow an AST after a limited browsing period during early succession.

Sport hunting may help in controlling cervid populations over large areas. As with natural predators, several environmental factors can influence sport harvest. A better understanding of the environmental variables that limit the efficiency of sport hunting could provide guidelines for more efficient wildlife management using hunting. We studied white-tailed deer (Odocoileus virginianus) hunting on a high deer density island where hunting was the sole form of predation. Our objective was to study the behavior of sport hunters and determine the habitat characteristics (e.g., abundance of deer forage, visibility of the deer from the hunter's point of view, and accessibility of the territory to hunters) that are associated with a successful harvest. We collected movements and harvest site location data from 477 hunters equipped with handheld Global Positioning System (GPS) units. Harvest sites were visited and characterized, along with a paired random site, to determine the environmental conditions associated with a successful hunt. We also developed a model to predict the daily number of deer seen by hunters considering weather conditions, hunter characteristics (e.g., age, experience), and date of hunting. We used the mean number of deer seen per hunter per day as a relative index of local density in each hunted territory. At both the site and landscape scales, the combination of visibility and access had a positive effect on the distribution of harvested deer. Habitat types with less visual obstruction from vegetation enabled hunters to see more deer in a given day. At the site scale, harvested deer were located in areas with a lower density of access routes compared to areas where hunters travelled throughout the day. Using an innovative approach of studying hunter behavior with GPS technology, digital maps, and questionnaires, we highlighted the factors associated with hunter success. Our study suggests that habitat characteristics could be modified to increase harvest by improving accessibility and visibility near roads. Creating openings in mature and regenerating forest near access roads could make sport hunting a more efficient management tool, but the potential impact of increased forage availability in forest openings should not be overlooked.

The exclusion of herbivores in forest areas is a strategy used to reduce the impact of selective browsing and increase the regeneration of desired plant species. On Anticosti Island (Québec, Canada), selective browsing by white‐tailed deer prevents the regeneration of balsam fir – white birch forests leading to their conversion into white spruce forests. Large deer exclosures were established for ca 10–12 years in clear‐cuts with patches of residual forest from 2001 to 2006 to assist in the natural regeneration of fir stands and to provide shelter and food resources for deer. Our objective was to assess how deer use exclosures after the removal of fences according to their spatial configuration and habitat composition. We randomly distributed automatic cameras for periods of 14 days during summer in six exclosures ranging from 3.1 to 11.2 km2 (n = 25 cameras per exclosure) from which deer were reduced for 10–12 years. We compared candidate occupancy models that included spatial configuration and food resource variables while simultaneously controlling for variables affecting detection probability. We obtained weak evidence that deer habitat use increased by 19% when forage resources, represented by the cover of Cornus canadensis, increased from 0 to 100%. None of the other variables (distance between the border of exclosures and cameras and distance between forest patches and cameras) was retained, suggesting that the use of regenerating forests by deer in summer after a period of exclusion is related to forage availability and therefore, any forest management that improves food production during summer should help maintain or increase habitat use by deer.

Anticosti Island, Canada, has long been recognized as an exceptional Ordovician–Silurian boundary succession with the potential to serve as one of the best records of climatic, oceanographic, and biological events associated with the Late Ordovician mass extinction. However, differing interpretations as to the position of the Hirnantian Stage within the stratigraphic succession due to the paucity of diagnostic graptolites, the apparent absence of a typical Hirnantia fauna within the Upper Ordovician Ellis Bay Formation, and lateral facies variability among outcrops has hindered the study of the Ordovician–Silurian boundary on the island, particularly in the eastern half of the outcrop belt. Definitively identifying the stratigraphic position of the Hirnantian Stage within the succession is therefore critical for understanding this classic Ordovician–Silurian boundary section, as well as for the integration of data from Anticosti into our global understanding of the Late Ordovician mass extinction. Here, we take an integrative approach to studying the Ellis Bay and lowermost Becscie formations, combining new paleobiological, geochemical, radiometric, and sequence stratigraphic constraints from ongoing fieldwork with existing biostratigraphic, geochemical, and palynological studies in the context of newly measured stratigraphic sections. These formations record six depositional sequences bounded by regionally traceable but subtle unconformities, often mantled by thin siliciclastic veneers reworked into transgressive lag facies. Many of these unconformities have gone unrecognized despite more than a century of work at certain localities. Furthermore, despite previous controversy, multiple lines of evidence favor a Hirnantian age for the entire Ellis Bay and lowermost Becscie formations, including newly recognized occurrences of Hirnantia and Hindella in the lower Ellis Bay Formation, a two-phased positive carbon isotope excursion, with the second phase reaching ~6‰ in the Laframboise Member of the Ellis Bay Formation, and a U-Pb TIMS age of 443.61 ± 0.52 Ma from zircons in a bentonite from the mid-Ellis Bay Formation. While graptolite and conodont biostratigraphy support this age model, determination based on chitinozoan biozonation is more equivocal but may be controlled by facies preferences. Conodont, brachiopod, and chemostratigraphic data additionally suggest that the Hirnantian Stage may extend slightly into the lower Becscie Formation on the western end of Anticosti and well into the lower Becscie Formation in the eastern part of Anticosti. Our reappraisal of a classic Ordovician–Silurian boundary section has important implications for understanding the sequence of climatic, environmental, and biological events throughout the Late Ordovician mass extinction. Given that the Ellis Bay and lowermost Becscie formations are indeed Hirnantian in age (encompassing ~2 My), these formations record six fourth-order depositional sequences of approximately ~333 ky. Furthermore, comparison of the Hirnantian of Anticosti to coeval exposures suggests that other regions may be incomplete at the level of the fourth-order cycles that occur in the Ellis Bay Formation. Resulting uncertainties in correlations based on unconformities and interpretations of stratigraphic architecture may therefore greatly complicate global correlation of Hirnantian records. Further study of this issue is critical, as stratigraphic architecture is expected to be an overarching control on the expression of oceanographic, climatic, and biotic events at a regional scale, complicating the interpretation of the pattern and drivers of the Late Ordovician mass extinction.

Overabundant populations of cervids have induced drastic negative effects on plant communities in several regions worldwide. Antlerless deer harvest by sport hunters has been proposed as a potential solution to overabundance because the philopatric behavior of female deer is expected to limit recolonization of hunted zones. The efficiency of this method, however, has rarely been tested in the wild. Using a large-scale experimental design, we reduced white-tailed deer (Odocoileus virginianus) density within 5 20-km2 areas on Anticosti Island (Québec, Canada). Our objective was to harvest 50% of antlerless deer in each site during the first year of the study in 2002, and 30% from 2003 to 2006. We monitored deer density, vegetation abundance and growth as well as deer life-history traits during 6 years in these experimental sites and in 5 control sites where harvest rate was 5-7%. Overall, we achieved 93% of harvest objectives. Contrary to our expectations, however, deer density, vegetation abundance and growth, and deer life-history traits did not vary differently in experimental and control sites during the study period. They rather varied stochastically but synchronously. We discuss several alternative hypotheses that may explain these results, including 1) compensatory mechanisms, 2) biases in density estimates, 3) limited access to territory for hunters, 4) large target areas for localized management, 5) low hunter density, 6) recolonization by surrounding deer, 7) slow plant response under canopy cover, and 8) bottom-up mechanisms. Given the large efforts invested in this study, we conclude that the local control of abundant cervid populations through sport hunting may be difficult to achieve in many natural environments.

End-Ordovician extinctions had a profound effect on shallow-water benthic communities, including the Crinoidea. Further, recovery after the extinctions resulted in a macroevolutionary turnover in crinoid faunas. Anticosti Island is the most complete Ordovician-Silurian boundary section recording shallow-water habitats. Both new taxa and changes in Anticosti Island stratigraphic nomenclature are addressed herein. New taxa include Becsciecrinus groulxi n. sp., Bucucrinus isotaloi n. sp., Jovacrinus clarki n. sp., Plicodendrocrinus petryki n. sp., Plicodendrocrinus martini n. sp., Thalamocrinus daoustae n. sp., and Lateranicrinus saintlaurenti n. gen. n. sp. The status of Xenocrinus rubus as a boundary-crossing taxon is confirmed, range extensions of several taxa are documented, and the distribution of crinoids with the revised stratigraphic nomenclature is documented.

The subfamily Hindellinae is an early group of athyride brachiopods, characterized by a simple jugum that connects the laterally directed spiralia, which are disjunct from the crura. Four genera (Hindella, Cryptothyrella, Koigia, and Hyattidina) are reexamined on the basis of their internal structures, such as the crura and their connection to the hinge, the jugum, and spiralia. The internal brachidium and shell of the Aeronian genus Cryptothyrella differ substantially from those of Hindella. Elkanathyris pallula n. gen. n. sp. is recognized as a posteriorly ribbed hindellide of Aeronian age. These genera are transferred from the Meristellinae to the subfamily Hindellinae (family Hindellidae). On Anticosti Island, Hindella is confined to the Hirnantian (latest Ordovician): it became extinct at the end Ordovician during the last of several mass extinction events that also extinguished the Laframboise reefs at the top of the Ellis Bay Formation. Post-extinction recovery of athyrides was pioneered by small-shelled Koigia, which are abundant in the basal Silurian Becscie Formation. Hyattidina, with a simple brachidium, is abundant in the Aeronian and Telychian of Anticosti, but absent earlier. True meristellines, as envisioned here, first appeared in the Aeronian Gun River Formation. The revised taxonomy and stratigraphic ranges of these earliest athyrides shed light on the nature of the Ordovician–Silurian mass extinction and recovery, and help refine the biostratigraphy of the O-S boundary interval.

Understanding how large herbivores shape plant diversity patterns is an important challenge in community ecology, especially because many ungulate populations in the northern hemisphere have recently expanded. Because species within plant communities can exhibit strong interactions (e.g., competition, facilitation), selective foraging by large herbivores is likely not only to affect the abundance of palatable species, but also to induce cascading effects across entire plant communities. To investigate these possibilities, we first tested the effects of deer browsing and soil disturbance on herbaceous plant diversity patterns in boreal forest, using standard analyses of variance. Second, we evaluated direct and indirect effects of deer browsing and soil disturbance on the small-scale richness of herbaceous taxa using a multilevel path analysis approach. The first set of analyses showed that deer browsing and soil disturbance influenced herb richness. Path analyses revealed that deer browsing and soil disturbance influenced richness via complex chains of interactions, involving dominant (i.e., the most abundant) browsing-tolerant (DBT) taxa and white birch ( Betula papyrifera ), a species highly preferred by white-tailed deer ( Odocoileus virginianus ). We found no evidence that an increase of white birch in fenced quadrats was the direct cause of a decrease in herb richness. However, we found strong evidence that a higher abundance of DBT taxa (i.e., graminoids and Circium arvense ), both in fenced and unfenced quadrats, increased herb layer richness. We propose an empirical model in which competitive interactions between white birch and DBT taxa regulate the strength of facilitative relationships between the abundance of DBT taxa and herb richness. In this model, deer browsing and the intensity of soil disturbance initiate a complex chain of cascading effects in boreal plant communities by controlling the abundance of white birch.

Rhenopyrgids are rare, turreted edrioasterid edrioasteroids from the lower Paleozoic with a distinctive and apparently conservative morphology. However, new, well-preserved rhenopyrgid edrioasteroid material from Canada, along with a review of described taxa, has revealed broader structural diversity in the oral surface and enabled a re-evaluation of rhenopyrgid functional morphology and paleoecology. The floor plates in Rhenopyrgus viviani n. sp., R. coronaeformisRievers, 1961 and, R. flosKlug et al., 2008 are well fused to each other and the interradial oral plate and lack obvious sutures, thereby forming a single compound interradial plate. This differs from other rhenopyrgids where sutures are more apparent. Such fused oral surface construction is only otherwise seen in some derived edrioblastoids and in the cyathocystids, suggesting homoplasy. Our analysis further suggests that the suboral constriction could contract but the flexible pyrgate zone could not. Thus, specimens apparently lacking a sub-oral constriction should not necessarily be placed in separate genera within the Rhenopyrgidae. It also supports rhenopyrgids as epifaunal mud-stickers with only the bulbous, textured, entire holdfasts (coriaceous sacs) anchored within the substrate rather than as burrow dwellers or encrusters. Rhenopyrgus viviani n. sp. is described from the Telychian (lower Silurian) Jupiter Formation of Anticosti Island, Québec, Canada and is differentiated by a high degree of morphological variability of pedunculate plates, broader oral plates, and narrower distal ambulacral zones. Specimens lacking or with obscured diagnostic plates from the Ordovician of Montagne Noire, France, and the Ordovician and Silurian of Girvan, Scotland are also described.

Endobiotic tentaculitoids formed symbiotic associations with tabulates, heliolitids, rugosans, bryozoans, crinoids, stromatoporoids, and chaetetids from the Late Ordovician to the Carboniferous. The Ordovician was dominated by coral hosts, but there was a shift from mostly coral-based associations to stromatoporoid-based associations in the early Silurian. Specialization increased during the evolution of tentaculitoid symbiosis. In the Devonian, specialized symbiotic endobiont genera appeared which did not occur separately from their hosts.