The mosses of Terra Nova National Park, Eastern Newfoundland, a bryofloristic analysis and interpretation

The known moss flora of Terra Nova National Park, eastern Newfoundland, comp~ises 210 species. Eighty-two percent of the moss species occurring in Terra Nova are widespread or widespread-sporadic in Newfoundland. Other Newfoundland distributional elements present in the Terra Nova moss flora are the northwestern, southern, southeastern, and disjunct elements, but four of the mosses occurring in Terra Nova appear to belong to a previously unrecognized northeastern element of the Newfoundland flora. The majority (70.9%) of Terra Nova's mosses are of boreal affinity and are widely distributed in the North American coniferous forest belt. An additional 10.5 percent of the Terra Nova mosses are cosmopolitan while 9.5 percent are temperate and 4.8 percent are arctic-montane species. The remaining 4.3 percent of the mosses are of montane affinity, and disjunct between eastern and western North America. In Terra Nova, temperate species at their northern limit are concentrated in balsam fir stands, while arctic-montane species are restricted to exposed cliffs, scree slopes, and coastal exposures. Montane species are largely confined to exposed or freshwater habitats. Inability to tolerate high summer temperatures limits the distributions of both arctic-montane and montane species. In Terra Nova, species of differing phytogeographic affinities co-occur on cliffs and scree slopes. The microhabitat relationships of five selected species from such habitats were evaluated by Discriminant Functions Analysis and Multiple Regression Analysis. The five mosses have distinct and different microhabitats on cliffs and scree slopes in Terra Nova, and abundance of all but one is associated with variation in at least one microhabitat variable. Micro-distribution of Grimmia torquata, an arctic-montane species at its southern limit, appears to be deterJ]lined by sensitivity to high summer temperatures. Both southern mosses at their northern limit (Aulacomnium androgynum, Isothecium myosuroides) appear to be limited by water availability and, possibly, by low winter temperatures. The two species whose distributions extend both north and south or the study area (Encalypta procera, Eurhynchium pulchellum) show no clear relationship with microclimate. Dispersal factors have played a significant role in the development of the Terra Nova moss flora. Compared to the most likely colonizing source (i .e. the rest of the island of Newfoundland), species with small diaspores have colonized the study area to a proportionately much greater extent than have species with large diaspores. Hierarchical log-linear analysis indicates that this is so for all affinity groups present in Terra Nova. The apparent dispersal effects emphasize the comparatively recent glaciation of the area, and may also have been enhanced by anthropogenic influences. The restriction of some species to specific habitats, or to narrowly defined microhabitats, appears to strengthen selection for easily dispersed taxa.

Restoring forests degraded by overabundant moose on the island of Newfoundland

Global forests are being degraded at an alarming rate; hence ecological restoration becomes an integral component ensuring future forest health. Beneficial effects of restoration will arise from scientifically based practices that are efficient and effective. On the island of Newfoundland, moose (Alces alces) have become overabundant since their introduction in early 1900’s. Intensive selective browsing by moose on foundation species such as balsam fir (Abies balsamea) interacts with natural insect disturbance and limits advanced regeneration, creating moose meadows. In this thesis, I focused on where and how active restoration should be implemented in Terra Nova National Park (Newfoundland, Canada) balsam fir forests within the context of the natural disturbance regime under conditions of overbrowsing. Environmental surveys and experimental seedling planting were carried out along a disturbance gradient from closed canopy forest to large insect-disturbed stands. To develop cost-effective and science-based planting protocols, several ground treatments were tested to enhance seedlings success: (1) control, field planting, (2) removal of the aboveground vegetation and (3) ground scarification. Results indicate that (1) priority for restoration should be given to insectdisturbed areas > 5 ha rather than smaller gaps, and (2) that active restoration should be implemented following scientifically determined field planting protocols, as no substantial benefit was detected following ground treatment. The recommendations arising for this thesis allow for the development of efficient and effective protocols towards the reestablishment of multi-aged balsam fir forests in Newfoundland.