GREATER FUNDY ECOSYSTEM RESEARCH PROJECT
UNB Faculty of Forestry and Environmental Management
State of the Greater Fundy Ecosystem
Ecological Change in the Greater Fundy Ecosystem
Graham Forbes1, Hilary Veen2, Judy Loo3, Vincent Zelazny2, and Stephen Woodley4
1 Sir JamesDunn Wildlife Research Centre, University of New Brunswick, Fredericton, NB E3B 6C2
2 New Brunswick Dept. of Natural Resources and Energy, Fredericton, NB E3B 5H1
3 Canadian Forest Service - Atlantic Region, P.O. Box 4000, Fredericton NB E3B 5P7
4 Natural Resources Branch - Parks Canada, Hull, Que. K1A 0H3
Ecosystems are dynamic and change over space and time through processes of disturbance, succession, decomposition and migration. Over hundreds and thousands of years the climate warms and cools and glaciers come and go. Such external and internal stresses cause natural systems to react. Sometimes the natural system is resilient and little changes. Other times, the stress is large enough to dramatically change the landscape. In this respect, species extinction and creation is a natural process that occurs over many years. It is now suggested through geological evidence that species extinction and creation is interspersed with catastrophic die-off about every 26 million years (Raup and Sepkoski, 1984).
The rates of extinction today, however, arise from human activity and are 1,000 to 10,000 times greater than natural rates (Wilson, 1988). The worldwide demand for natural resources means that ecosystems will continue to be altered. How the natural system responds to these stresses will dictate the ecological health of an area and the rate of change it experiences.
NATURAL DISTURBANCE REGIMES
A variety of natural disturbances play an integral role in the long-term maintenance of ecosystems (Christensen, 1988). The main natural disturbance agents in New Brunswick are epidemics of the Spruce Budworm, fire and wind (Methven and Kendrick, 1995).
A total of six Spruce Budworm outbreaks have been documented in New Brunswick since 1760. Before 1900, the return interval was 42 and 75 years. After 1900, the return interval increased to every 19 to 34 years (Blais, 1983). The increase in the return interval can probably be attributed to human activities, such as long-term selective Spruce harvesting, changes in harvesting standards brought about by the rise of the pulp and paper industry, pesticide spraying to protect Balsam Fir, and fire suppression (Blais, 1983; Seymour, 1992). All these activities have served to increase the amount of mature Balsam Fir on the landscape. Spruce Budworm disturbance cycles can therefore be linked to the longevity of Balsam Fir and a landscape dominated by a single age class of Balsam Fir that would advance over time until the next outbreak.
Spruce budworm larvae (Photo: B. Townsend)
Pines, Black Spruce, Oak and Trembling Aspen are just a few species dependent on fire for successful regeneration. A study of the present distribution of fire-dependent species provides clues on the distribution of natural fires. Natural stands of Red and Jack Pine and Red Oak do not occur on the Fundy Coast or the Fundy Plateau because the cool, wet climate precludes wildfires (Power and Matson, 1995). White Pine does occur on a small number of sun-exposed river canyon cliffs and edges and slopes where temperatures rise high enough to permit germination (Power and Matson, 1995).
Forest fire (Photo: Fundy NP)
It is likely that fire, in prehistoric times, varied significantly in frequency by ecoregion because of the wide range of geomorphic and climatic conditions. Although information is sparse, it also appears that aboriginal peoples may have extensively used fire to alter the landscape. Evidence for this comes from information gathered in New England (Day, 1953; Denevan, 1992) and the present-day occurrence of extensive stands of Jack Pine, upland Black Spruce, and Red and White Pine, in some areas of the province. Lightning and human-caused fires began to be actively suppressed in the province in the 1930s. As a result, it is difficult to separate human effects on fire frequency and size in more recent times from that which would occur naturally.
FireNB (RemSoft Inc.) is a computerized forest fire simulation model which allows the user to estimate the frequency and size of wildfires over time as a function of fuel-type, local climate and landscape character, including topography and the presence of natural firebreaks such as rivers. The program was run by Zelazny et al. (1997) on the area of the FMF in two simulations. The first simulation removed fuel-type as a variable, thus highlighting the landscape-level climatic and geomorphologic controls (i.e. fire breaks such as rivers) on fire size (Table 3.1). The second simulation used ecosite maps as a proxy for fuel-type (Table 3.2).
Table 3.1. Summary fire statistics from FireNB without fuel effects (Simulation 1)
Table 3.2. Summary fire statistics from FireNB including fuel effects (Simulation 2).
Fire cycle assumes a fire rate of 0.45 lightning fires per 1,000 sq. km. per year
(Wein and Moore, 1997)
Results from these simulations suggest that the Fundy Coastal Ecodistrict and the Fundy Plateau Ecodistrict were infrequently burned, apparently due to the cool, moist climate, and, in the case of the Fundy Plateau, unfavourable fuel-type due to the high frequency of hardwood and mixedwood stands. The highest frequency of fires of a large size occurred in the Petitcodiac River Ecodistrict. The Anagance Ridge Ecodistrict was intermediate in the frequency of fires of a large size. A predominance of relatively fire-resistant mixedwood forest types on fertile slopes, and the presence of significantly large lakes and rivers (fire breaks), limit the size of fires, except on poor soil sites where Pines are still an important forest component. As expected, the ecodistricts in the Eastern Lowlands Ecoregion (e.g. Petitcodiac River) have the shortest fire cycles and the two ecodistricts along the coast (Fundy Plateau and Fundy Coastal) have the longest. Fires appear to be relatively rare in the Continental Lowlands Ecoregion (Anagance Ridge Ecodistrict) and rarer in the Fundy Coastal Ecoregion (Fundy Coastal Ecodistrict).
On the Fundy coast, wind disturbance is probably a more important stand-replacing disturbance than in the rest of southern New Brunswick. However, this susceptibility extends no more than 0.5 km inland. For the Continental Lowlands Ecoregion (Anagance Ridge Ecodistrict) and the Southern Uplands Ecoregion (Fundy Plateau Ecodistrict), the return interval for blowdowns larger than 25 ha. has been estimated to be more than 1,000 years. Small patch and individual tree blowdowns that create small gaps of various sizes in the forest are the most frequent type of disturbance. Non-clearcut harvesting techniques such as strip cuts, selection cuts, and shelterwood would be most appropriate forestry techniques in these forest situations to best approximate the natural forest condition in these areas.
Fallen trees, such as this Red Spruce, create openings in
forest canopies which allow regeneration of Red Spruce
and other species (Photo: A. Skibicki)
POTENTIAL FORESTS OF THE GFE
Although it may be impractical to completely re-create the forest landscape of the past because of changes due to agriculture, forestry and urbanization, it is valuable for resource managers to determine a historical benchmark for comparing human impacts. Potential vegetation is the late-successional stand composition and pattern of forest types that would have existed before farming, harvesting, and fire and insect suppression began dominating forest dynamics in the region. A study recently completed by Zelazny et al. (1997) for the FMF was intended to provide a best estimate description of the potential forest of the FMF area.
The distribution of forests across the landscape is dependent on an inherent pattern and an induced pattern. The inherent pattern is the environment on which the forest grows. It is comprised of non-living ecosystem features such as climate, topography, bedrock and soils. In Zelazny et al., the Ecological Land Classification (ELC), at the ecosite level, was used to describe this inherent pattern.
The induced pattern is caused by natural disturbance regimes such as fire, windstorm, insect and disease attacks and small canopy gaps. After estimates are made of where potential forest would occur based on the inherent pattern, further refinement can be made with a good understanding of the disturbance regimes.
The ELC for New Brunswick provided area summaries of forest communities by ecosite. These areas were then adjusted based on photointerpreter error and amount of area in abandoned fields. Information on disturbance regimes, including the previously mentioned fire model, was used to give further insight on distribution of forest communities. These descriptions of potential/historical forests can be used in management planning.
Figure 3.1 shows the potential forest vegetation for the Intensive Study Area (ISA) of the GFE. Figure 3.2 shows present day forest types in the ISA grouped into generalized categories of softwood, mixedwood and hardwood. The following sections describe the potential forest composition within the ecodistricts comprising the ISA.
Figure 3.1. Potential forests of the GFE's Intensive Study Area, by ecosite.
Figure 3.2. Present day (1993) forest types of the GFE's Intensive Study Area.
Potential Forests of the Fundy Coastal Ecodistrict
Within the ISA, the Fundy Coastal Ecodistrict to the west of Alma is dominated by almost pure Red Spruce communities. These communities occur on the higher plateaus (Ecosite 5h) and coniferous steep valley slopes (Ecosite 2s)(Figure 3.1). The remainder of this area consists mainly of mixtures of Red Spruce with White and Black Spruce, or Balsam Fir with some Red Maple, White Birch and Yellow Birch. To the east of Alma, the moist, gentle slopes (Ecosite 2) are historically dominated by a high proportion (60%) of Red Spruce communities, with lesser amounts of Black Spruce, Cedar and mixedwood. A number of Black Spruce peat bogs (Ecosite 3b) and cool, rocky coastal niches support remnant populations of sub-arctic species. Typically found on dry slopes (Ecosite 4) and moist upper slopes (Ecosite 7) are a small number of tolerant hardwood stands, comprised mostly of Yellow Birch, with small quantities of Sugar Maple and Beech. Heat-loving species such as Pine, Oak, Ironwood, and Ash are virtually absent from this ecodistrict. After harvesting, the intolerant hardwood community is mostly White Birch with Red Maple and Yellow and Grey Birch.
Harvesting which promotes Red Spruce regeneration will promote value throughout the ecodistrict. Hardwood management is best suited to Ecosites 4 and 7. Black Spruce is best suited to the wet soils of Ecosite 3.
Potential Forests of the Fundy Plateau Ecodistrict
Well-drained hilltops and upper slopes (Ecosite 8) dominate the Fundy Plateau Ecodistrict in the ISA. Historically, Ecosite 8 supports a tolerant hardwood association of Sugar Maple, Yellow Birch, and Beech, often with a Red Spruce component. Mixedwood communities of Red Spruce, Yellow Birch, Red Maple, and some Balsam Fir are typically found on gentle slopes and upland flats (Ecosite 5). Valley bottoms (Ecosite 2) and flat areas with impeded drainage (Ecosite 3) are few and often support pure stands of Spruce and Balsam Fir. Sugar Maple, Red Spruce, Yellow Birch, and White Ash are the most valuable timber producing species. In formerly harvested areas, the vegetation is mostly White Birch in mixture with Yellow Birch, Trembling Aspen, and Balsam Fir. Scarcity of Pine, Black Spruce and Poplar suggests a low frequency of fire due to the cool, wet climate.
Limiting clearcuts on the well-drained hilltops and upper slopes (Ecosite 8) will favour tolerant hardwoods and Red Spruce, while shelterwood or group selection harvests would promote natural value in Red Spruce-dominated communities. Red Spruce and Balsam Fir are the preferred species of Ecosite 2, while Black Spruce is best suited to Ecosite 3 and 3b. For maximum productivity, silvicultural activities should be undertaken first in Ecosites 5 and 8.
Potential Forests of the Anagance Ridge Ecodistrict
Parts of the Anagance Ridge Ecodistrict extend over the north and northwest corner of the ISA. This part of the ecodistrict is characterized by hardwood ridge (Ecosite 8), hardwood dry ridge or steep slope (Ecosite 9), lower acidic slopes (Ecosite 2) and moist mixedwood calcareous upper slope (Ecosite 7c). Historically, Ecosite 8 is composed of tolerant hardwood stands of Beech, Sugar Maple, and Yellow Birch with a minor component of White Ash and Ironwood. Higher elevation areas have been heavily disturbed by logging and are today dominated by intolerant hardwoods such as Red Maple, Trembling Aspen, Large-toothed Aspen, White Birch, and Grey Birch. Ecosite 9 (dry, ridge tops) is characterized by these intolerant hardwoods and also has a Beech component, suggesting that a Beech-dominated climax community would develop on the sandy, nutrient poor soils. Ecosite 2 is characterized by White Pine, Jack Pine, and Red Pine.
The area today has many agricultural fields, both active and abandoned, which quickly revert to White Spruce, often mixed with Red Spruce, Balsam Fir, and White Birch. Jack Pine may occupy old fields on sandy soils. Harvesting and fires have also altered the landscape, leaving many areas comprised of short-lived, intolerant hardwoods. Limiting clearcutting on Ecosite 7c would favour longer-lived, more valuable tolerant hardwoods including White Ash.
POSSIBLE RESPONSES TO FOREST CHANGES
What the future holds for our forests is difficult to know, partly because regional climate change scenarios are presently not well understood. Some scientists believe that species that thrive in warmer and drier environments, such as White Pine, Sugar Maple, and Beech, will have a natural advantage over species of cold, humid environments, such as Spruce and Balsam Fir, which may move further north as the climate warms (Jacobson et al., 1987). Others see Spruce and Balsam Fir gaining ground in the GFE area in the coming decades and centuries because expected temperature variability will cause further dieback in hardwoods which are more susceptible to this process. Insects and disease outbreaks will continue to affect the forest in ways that are difficult to predict. These factors interact with others, including atmospheric nutrient and acid input, which makes prediction of future trends of natural forest change very difficult and risky.
In addition, human activity in the post-settlement period has resulted in a reduction in the number of tree species of moderate to high shade tolerance in the forest, and an increase in the dominance of shade-intolerant hardwood species, and other species readily able to exploit clearcuts, such as Balsam Fir and Red Maple.
Given the uncertainties associated with future climate change, a reasonable forest objective for the working landscape would be to conserve the genetic and species diversity of trees in the forest, or to re-introduce species and genetic diversity where its loss is suspected. The principal benefit is the building of forest stability and resilience for an uncertain future by building stand-level diversity of tolerant and moderately tolerant species. A second benefit of managing for diverse natural regeneration reflecting historical composition is the conservation of microsite variability throughout the forest, which would have positive effects on non-tree species that have limited area requirements, such as many plants, animals and fungi. This does not mean that every species should be propagated everywhere. Rather, species should be matched to the sites where they can be expected to thrive. Natural forest landscape patterns of recent prehistoric and historic time provide clues to how this can be done.
Replacement of lost diversity can be attempted by various means, including seeding or planting. Where species and genetic diversity remains intact, harvesting should be conducted so as to maintain species and genetic diversity through natural regeneration. Increased use of tactics such as partial harvesting and limiting opening sizes will provide seed sources and a variety of microsite conditions that will promote diversity at the stand level.
REMNANT FOREST COMMUNITY TYPES
A number of forest community types were historically more common in the GFE than they are today. The following remnant forest community types are described by MacDougall and Loo (1996). They include: Hemlock slope forest, Pine-Oak forest, wet Cedar forest, and coastal ravine Red Spruce forest.
The Hemlock slope forest is found in cool moist conditions such as shady ravines, streamsides, and north-facing slopes. Associated species include Red Spruce, White Pine and Yellow Birch. This community type is uncommon in the GFE today, though it was likely more frequent prior to the intensive exploitation of coniferous species during the past two centuries.
A Hemlock slope forest in the GFE (Photo: G. Forbes)
The Pine-Oak forest community type was probably also more common in southern New Brunswick than its scattered and uncommon occurrence today would indicate. White Pine was heavily harvested for commercial and military use during the late 1700's and early 1800's.
The wet Cedar forest community type has decreased in frequency throughout much of New Brunswick and particularly in the south-central part of the province where much land was cleared in the past for agriculture. The community type often occurs on alkaline soils which are also conducive for growing Clover. Many Cedar forests were drained and cleared to plant Clover fields by the mid 1800's. A number of plant species that are now rare or uncommon are associated with wet Cedar forests.
The coastal ravine Red Spruce forest community type generally occurs on well-drained to moderately well-drained soils along the sides and rims of coastal ravines. Some individual Red Spruce trees in these ravines reach large sizes and ages of 300 years or more. Many of the ravines were used for log drives in the last century, with the result that the existing patches of undisturbed stands of old trees are small and scattered. Other tree species associated with this community type include Balsam Fir, Black Spruce, Red Maple, White Birch, and Yellow Birch. Although vascular understory vegetation is sparse, the sites represent a reservoir of pure Red Spruce genes that may be diminished elsewhere.
Other remnant forest community types that occur at a greater distance from Fundy NP include the Sugar Maple-White Ash-Ironwood-Beech community type and the Silver Maple-American Elm alluvial bottomland community type. Both of these community types have been extensively cleared for agriculture and settlement, and a number of associated plant species have become rare or locally extirpated as a result.
TREE SPECIES FREQUENCY AND DISTRIBUTION CHANGE IN KINGS COUNTY
Until recently, hypotheses about tree species composition changes, as a result of human intervention, in this area of New Brunswick were based on anecdotal evidence and stand successional models. A recent study using witness tree data by Lutz (1997) has provided more direct evidence of species compositional changes for Kings County in southern New Brunswick. Kings County extends to the west of the GFE (Figure 3.3) but habitat change here has been similar throughout southern New Brunswick.
Figure 3.3. Location of Kings County
Witness trees were property line and corner markers, blazed by early surveyors. The surveyors were instructed to mark the tree at the corner and at specified distances along property sides, instead of tying in to the closest appropriate tree in the stand, as surveyors were instructed to do in the New England states.
Original land grants were surveyed in this part of New Brunswick from 1775 to about 1835, and surveyors recorded the species, or at least the genus, of the witness trees, yielding almost 4000 points scattered across Kings County. Aside from possible harvest of White Pine for ship masts, and possibly occasional fire setting by the aboriginal population of the area, human impact on the forests is thought to have been minimal before the land was granted. Thus, the frequency and distribution of the witness trees is assumed to be a fair representation of the state of the forest before European settlement.
In the Lutz (1997) study, witness trees were mapped as a GIS layer, and species (or genus) frequency was estimated for each ecosite falling, at least in part, within Kings County. Present-day species frequency and distribution were estimated for each ecosite using Forest Development Survey (FDS) basal area data collected in 1986 and 1993. Part of five ecoregions, ten ecodistricts, and 23 ecosites are included in Kings County but more than 80% of all of the historical and present-day data refer to the Continental Lowlands Ecoregion. Eleven percent of the witness trees and 8% of the FDS data were from the Southern Uplands Ecoregion, primarily representing three ecosites.
Table 3.3 presents a summary of the species, or genus, frequency for Kings County circa 1800 and today. In general, the data indicate that Balsam Fir, Spruce and Poplar species increased substantially, by factors of 2.7, 1.4, and 2, respectively, while many other species decreased. Notably, Cedar, Beech, Ash, Larch, and Hemlock each appear to have been reduced to less than half of their previous frequency. Other hardwood genera showed increases in some areas and decreased frequency in other areas, probably reflecting a reduction in frequency of tolerant hardwood species on the ridge tops, and an increase in the intolerant hardwood species of the same genus in the lower areas.
Table 3.3. Percent tree species composition of pre-settlement and
present-day Kings County (Adapted from Lutz, 1997)
Figures 3.4 to 3.12 show species or genus frequency circa 1800 and today for the nine ecosites of the Continental Lowlands Ecoregion. Though the data sources for the two points in time are very different and confidence intervals have not been attempted, the major trends are clear.
Questions remain about the frequency of Pine two centuries ago, because the pine harvest in the area was initiated before much of the land was surveyed. Pine trees that remained in the forest by the early 1800's were marked with the kings arrow meaning that they belonged to the crown for construction of naval vessels and could not be legally harvested for other purposes. Thus bias is possible for two reasons; first because of the extensive previous harvest of pine in the province, the species may have already been depleted by the time the surveys were carried out; and second, because the trees marked with a kings arrow could be taken at any time, they would not be good candidates to mark as witness trees.
White Pines along Laverty Brook, Fundy NP
Natural and human-caused disturbance and combinations of the two have all influenced the observed changes in tree species frequency and distribution in Kings County. Between the time of the original land grant surveys and today, there have been several Spruce Budworm outbreaks, the Eastern Larch Beetle has had a substantial impact, beech bark disease, caused by an introduced combination of insect and fungus, has drastically reduced the frequency of Beech. Dutch Elm Disease, caused by another introduced fungus, has virtually eliminated the small population of Elm that once inhabited the area, and Birch dieback, caused by unknown stressors, reduced the frequency of Birch species.
There were attempts to farm substantial areas of Kings County at one time. The farmland that was subsequently abandoned commonly grew into almost pure White Spruce stands. This accounts for some of the observed shift from hardwood species to Spruce. Balsam Fir and White Spruce are the preferential food sources for Spruce Budworm. During recent budworm outbreaks, forests with high proportions of conifers were treated with insecticide to extend their lifespan, thus further increasing the frequency of Spruce as well as Balsam Fir.
Balsam Fir was not considered a crop tree in harvesting operations until relatively recent times. Many of the other species were sought for speciality products, starting with White Pine for ship masts, Pine and Spruce for other building purposes, Hemlock for tannin, Ash for staves, Tamarack for ship building, Cedar for fence posts and shingles, Yellow Birch and Sugar Maple for furniture and cabinet making, and Beech and Sugar Maple for flooring. Harvest of these species was sequential, with the same area being picked over many times for different products. Through it all, a few species, such as Balsam Fir remained more or less untouched, allowing their frequency to gradually increase.
CHANGES IN SPECIES RICHNESS
Extinct and Extirpated Species
What is the impact to an ecosystem when most of the largest animals produced in the system are suddenly absent? Consider that only a few generations ago, the Gray Wolf, Eastern Cougar, and likely the Wolverine - the three largest and most efficient predators of large herbivores in the GFE - were extirpated, likely due to over-hunting. The last confirmed Gray Wolf in New Brunswick was recorded in 1921 (Lohr and Ballard, 1996), the last confirmed Eastern Cougar was last recorded before the 1900s. [Note: three cases of Cougar of unknown pedigree have been confirmed since 1931 (Cumberland and Dempsey, 1994; Stocek, 1995)]. The last confirmation of Wolverine comes from eight pelts that were sold at Saint John between 1764 and 1776 (Squires, 1946).
Another important species, both in being a food source for predators and for its foraging of plants, was the Woodland Caribou; a large ungulate that disappeared by 1935 (Squires, 1946). The Sea Mink, a coastal species similar to the Mink of rivers and wetlands, likely existed along the upper Bay of Fundy, but was extinct by 1860 (Waters and Ray, 1961). The Dwarf Wedge Mussel, native to the upper Bay of Fundy, is believed to have become extirpated as recently as the late 1960s.
A number of large bird species are known to have been lost in the last 100 years. The Eskimo Curlew and the Passenger Pigeon, species known to have migrated through or nested in the region, were abundant in the millions during migration, and hunted continent-wide to extinction in the late 1800s. The extinct Labrador Duck was documented along the New Brunswick coast, likely wintering after breeding in unknown areas to the north. Of the known native-species complement of 93 breeding birds in Fundy NP, two species, the Passenger Pigeon and the Spruce Grouse are no longer present. The Northern Leopard Frog, a species associated with drastic population declines in Canada, was recorded in Fundy NP in 1984, but could not be located during two years of amphibian surveys 10 years later (Clay and Brownlie, 1997).
Species loss extends to the plant community as well. Table 3.4 shows plant species in the GFE that likely have been extirpated since the late 1800s. The table shows the last time a particular species was found in the wild and catalogued within the provinces herbarium collection.
Table 3.4. Possibly extirpated plant species within the GFE. These species have not been
recorded in this area since 1960. The date shown is the most recent herbarium collection
Our ignorance of changes in the ecosystem is very evident whenever we discuss the status of such taxa as insects, mosses and lichens. Although these species comprise the majority of all species in the GFE, and play integral roles in its functioning, we know relatively little about their abundance, biology, and conservation needs. Without adequate historical records to compare with it is very difficult to determine which species are extirpated or newly arrived.
For example, one species of moss, Splachnum luteum, is thought to be extirpated, possibly due to the concurrent extirpation of the Woodland Caribou. All species in this genus occur on the dung of large herbivores, especially Moose and Caribou. S. luteum has only been collected once in New Brunswick, at an unspecified locality in Kent County, 1872 and it is speculated that its presence was a function of its reliance on dung found in boggy Black Spruce forests once used by Caribou (S. Clayden, NB Museum, pers comm.).
At the same time that some species have declined or disappeared from the GFE, other species have arrived (Table 3.5). About 132 of the 658 vascular plants in the area are non-natives released accidentally, or purposefully, from Europe, Asia, or other parts of North America. The impact of these exotic species on native systems is varied, ranging from unknown, to apparently benign, to a major stress. For example, Purple Loosestrife only became prevalent several years ago and already dominates some coastal wetland sites. One plant can produce 2.7 million seeds and, if dense mats are established, other wetland plants and associated animals can be displaced (White et al, 1993). In 1997, two leaf-feeding beetles (Galerucella pusilla and G. calmariencis) and a Coot-boring Weevil (Hylobius transversovittatus) were released in New Brunswick in an attempt to control Purple Loosestrife by using some of its European predators.
Norway Spruce is an introduced European tree which grows faster than native Spruce species. It has been planted in the GFE by forest managers for the past 60 years. In 1996 there was 0.4% (1,330 ha.) of Norway Spruce plantation in the Fundy Model Forest. Most of this was on J.D. Irving Ltd. and Crown land. About 10% of new plantation area being established in the FMF each year is in Norway Spruce (J. Pellham, pers. comm). Its impact to biodiversity in the area is not known.
The number of new vertebrate species, however, is much lower. Starlings and House Sparrows are common only in urban or farmed areas of the GFE, although Evening Grosbeak is widely present in both mixed and coniferous forest after arriving from western Canada in 1890 (Lewis, 1913; Christie, 1997). Although no new amphibian or reptile species have become established, three mammal species have become abundant. These include the Coyote, White-tailed Deer and Norway Rat. The first Coyote in the province was killed in Sussex in 1958 (Squires, 1968). Today, the Coyote is abundant throughout the region and feeds mainly on White-tailed Deer, Snowshoe Hare, and small rodents. The White-tailed Deer may have been present in very small numbers in the Maritimes but increased dramatically with the habitat changes associated with European arrival (Squires, 1946). The urban-associated Norway Rat is the only other new mammal species.
The Evening Grosbeak is a new bird in New Brunswick that may have
benefited from the presence of bird feeders and other
sources of winter food (Photo: D. Clark)
The White-tailed Deer has benefited greatly from land clearance
for farming and forestry (Photo: Fundy NP)
The number of new insect species is not known. Of the 675 or so species of macro-lepidoptera (larger sized butterflies and moths) identified in Fundy NP, 15 are known to be non-native, one of which was purposefully introduced to combat the Tansy Ragwort, a plant that is toxic to cattle. As well, 40 species of moth, which are known to occur in both Europe and the GFE, have uncertain origin (Table 3.6) There are also an estimated 600 or so species of micro-lepidoptera which have not been extensively inventoried in the GFE (Edsall and Clay, 1994; Thomas, 1997).
New viral or bacteria species have had a major ecological impact on several species and communities. Dutch Elm Disease was first recorded in New Brunswick in 1957, and has since killed most large Elm in the province (Canadian Forestry Service, 1985). The Beech Bark Canker disease and its associated insect pathogen, Beech Scale, have effectively eliminated large American Beech trees from the tolerant hardwood forests of the GFE (Burzynski et al., 1986). Both species arrived from Europe and were established in the GFE by 1927 (Hawboldt, 1944). As a mast producing tree, Beech must have been an important food source for many species. Beech now survives only in restricted areas and is generally infected by the Beech Canker (Burzynski et al., 1986). In a diseased state, the Beech produces very few seeds and thus its role as a food source is reduced. It is believed that the loss of beechnuts from the fall diet of Black Bear likely influences the productivity of bears in the GFE. Black Bears in northeastern forests would normally eat large amounts of the fat-rich beechnuts before hibernation. The overall lack in the autumn of hard mast (nuts of any species) other than Beaked Hazel possibly increases the need to frequent hunted bait stations.
Another species with numerous indirect effects is the parasitic Brainworm, Paralephostrongylus tenuis. As White-tailed Deer moved north into New Brunswick with the increase of young forest growth, they brought this parasite which is harmless to deer but fatal to Moose and Caribou.
Further changes can be expected. Eurasian Watermilfoil, an aggressive wetland species, has been moving north into New Brunswick from Maine since 1985 (White et al, 1993). The Butternut, a tree once common on sites with rich soils (Perley, 1847), was reduced by over-cutting and clearing for farm land. The remaining trees may soon face a new threat from a new fungus, Sirococcus clavignenti-juglanda cearum that has killed most of the Butternut in North America in only 15 years. The fungus reached Maine in 1993 and was confirmed in New Brunswick in 1997 (K. Harrison, pers. comm).
Some species in the GFE have returned on their own but others have been given assistance. The reintroduction of Atlantic Salmon is discussed in Chapter 6 of this report. The Fisher and the American Marten, two species of weasel that had been lost due to over-trapping and habitat change, have been reintroduced into the GFE.
The Fisher is a large-bodied, black weasel that had been extirpated in the area by the 1940's (Dilworth, 1974). Because it is a major predator of Porcupine and Snowshoe Hare, both of which influence regenerating forests, the return of Fisher to the ecosystem likely had far-reaching effects on vegetation, and plantations in particular. In 1966 and 1968, 16 Fisher (five male and 11 female), captured in northern New Brunswick, were released at the headwaters of the Pollett River (Dilworth, 1974). Two were trapped in the first winter near the northeast corner of the Park but only three more were known to be trapped in the next 10 years, and all of these were offspring of the re-introduction (Pettigrew, 1978). This species appears to have established well. A total of 206 Fisher have been commercially trapped in the region since 1985 (Figure 3.13).
Figure 3.13. Number of Fisher collected (thick line) and pelt value (thin line)
within three Wildlife Management Zones (WMZs) in the GFE.
Unlike Fisher, the restoration of the American Marten has not appeared to be successful. Fifty Marten (26 male, 19 female, and five newborn) were released in Fundy NP from 1984 to 1989 in the hope of re-establishing a Marten population that had been lost, by the 1930s, to over-trapping and habitat change (Bateman, 1982). However, a research program of intensive live-trapping from 1993-1995 only captured five male Marten, only one of which was a juvenile. The presence of a juvenile indicated that some breeding had occurred but the low captures suggest the population is not viable. A habitat assessment by Woodley (1993) suggested that the extent of fragmented forest and the small amount of mature conifer forest in the area limited the opportunity to maintain a viable population in the area.
The last recorded breeding of the Peregrine Falcon in the GFE occurred on the cliffs of Matthews Head, Fundy NP, in 1948, and for the entire Bay of Fundy region in 1955 at Cape d'Or, Nova Scotia (Stocek and Pearce, 1978). Twenty years later the Peregrine had been virtually extirpated in eastern North America because of the effects of toxic chemicals. Without a major restoration initiative undertaken by the federal government in the 1980s, it is likely that the fastest bird in the world would not be found in New Brunswick today. A total of 178 Peregrine chicks were hacked (slowly re-introduced from cages at release sites) between 1982-1991 from the cliffs along the Bay of Fundy, 55 of which were released at the Point Wolfe River in Fundy NP. In 1995, six breeding pairs had established in the Bay of Fundy, likely the historical density for the region (Amirault et al., 1997).
Peregrine Falcon (Juvenile)
Peregrine Falcon re-introduction in
Implications of Changes in Species Richness
The importance of richness and diversity of species has been likened to the rivets that hold the wings of a plane together. Some rivets (or species) play critical roles; located at crucial points along the wing, their loss would cause the plane (or ecosystem) to crash. Other, more numerous, species play supporting roles, and their loss may go unnoticed until another species, dependent on it for food or habitat, suddenly declines or increases. In this analogy we do not know where or when the critical moments occur. Both a mature tolerant hardwood forest and a cement parking lot have degrees of ecological integrity. The difference is important when scale and context is considered. For example, did the hardwood forest lose integrity when the pavement was poured or when the Flying Squirrels, Sugar Maples, or nematodes left?
The GFE has undergone substantial changes in its species richness since 1840. By far, the greatest relative loss of native species has been to the mammals and the greatest invasion of non-native species has been among vascular plants. It is important to understand that this measure of species richness does not measure the changes in abundance of individuals within a particular species. It also does not measure any resulting changes in the functioning of the ecosystem. In many cases there have been dramatic changes in the abundance of a species (eg. Beech), but the species has not become extirpated. The loss of some species is undoubtedly much more significant to the community than others.
Table 3.7 shows the number of known species in the GFE. However, the actual number of species is not known. Many taxanomic groups are not well studied, and with our present level of understanding, it appears that these numbers still reflect whether an expert has surveyed the area and likely not what is actually present. The arrival of an expert on insects or lichens will undoubtedly result in additional species being discovered to inhabit the GFE.
Table 3.7. Known number of species in Fundy NP.
The status of the larger, or well documented taxanomic groups, was determined as native or non-native, with native species defined as those species present as ongoing breeding populations prior to 1840. In all cases, if there was debate on whether a species still existed, it was assumed that it had been extirpated. An example of such debate is the Canada Lynx. A Lynx was shot outside the Park as recently as 1980. However, it was a rare event at the time, and the species is very rare in all of New Brunswick (Dilworth, 1984). In the case of birds, a few records exist of species that managed a single successful nest but have not been observed during the breeding season before or after. An example is a single successful Hawk Owl nest in 1989. This record was disregarded as anomalous.
It can be seen from Table 3.8 and Figures 3.14 and 3.15 that the species richness of both mammals and vascular plants has been largely altered. For mammals, a total of six native species, representing 14.3% of the total number of native mammal fauna, have been lost or are at such low levels as to be at risk in the ecosystem. There are now three non-native mammal species present, representing 7.7% of the total mammal fauna. There has been a dramatic invasion of non-native vascular plants, which now number 132 species, over 20% of the total number of species Twenty species of native vascular plants are believed to have been extirpated from the GFE area, out of a total of 524 native vascular plant species.
Table 3.8. A summary of the changes in species richness among
six taxonomic groups in Fundy NP from 1840 to 1997.
Figure 3.14. Comparison of the numbers of native vs. non-native
species among five taxonomic groups in Fundy NP.
Figure 3.15. Percent changes in native and non-native species composition
in Fundy NP, 1840-1997.
In contrast to mammals and vascular plants, breeding birds have been only slightly altered, and herpetofauna have decreased by just one species.
In total, there were 680 native species of mammals, birds, reptiles and amphibians, and vascular plants in the Fundy NP area prior to intensive land use by Europeans. Since 1840, 29 of those native species, comprising 4.3% of the total, have been lost to the community. There have been 138 non-native species, comprising 17.5% of the total, that have invaded and established reproducing populations.
The ecological impacts of non-native species are even more difficult to assess. The large majority of the non-native species are annual vascular plants, often invading old fields, ditches and disturbed areas. It can be readily observed that native species of vascular plants continue to dominate any of the areas not recently disturbed by human activity. However, non-native species of vascular plants are found throughout Fundy NP and can be found in the most remote forest stands.
In contrast to vascular plants, non-native species of mammals have come to dominate the Park. White-tailed Deer are the most common ungulate, and Coyotes are the most common predator. Both of these mammals species are considered ecological generalists that have moved into the landscape following alteration by humans. Both species can subsist off a wide variety of food sources and are found in a wide variety of habitats. It is generally agreed that biological invasions tend to both increase the numbers of ecological generalists and decrease the total numbers of species (Norton, 1992). These predictions are both true for mammals in the GFE. The total number of native mammal species has decreased from 42 to 36 species between 1840 and 1997, two of which were re-introduced by humans. Disregarding the re-introductions, there is a 14.3% reduction in native mammal species over that time period.
The body mass of native mammal species in the 1800s was 14.8% heavier than the species that comprise the community of mammals species today. The loss in body mass from extirpated Caribou, Wolf, Lynx, Cougar, Wolverine, and Sea Mink would constitute a decrease of 26.3% if not for the arrival of Deer and Coyote, and the reintroduction of Fisher and Marten. Between 1840 and 1997, there was a reduction in the average body size of the mammal fauna of the GFE by 10.6% If native species are considered alone, there was a reduction in the average body size of 15.6%.
The decline in average body weight is an indication of a loss in ecological integrity in the Fundy system. A stressed ecosystem tends to be unable to support large-bodied organisms and this trend is clear for Fundy. This decline corresponds to a period of intensive utilization of the landscape for forestry, agriculture, hunting and trapping. There is a clear correspondence between anthropogenic stress and the loss of these species (Corbett, 1985).
It could be argued that hunting by humans and Coyotes, and the arrival of White-tailed Deer has filled part of the ecological roles once played by Wolves, Cougar, and Caribou. However, we must admit that we just do not have the information to answer these questions.
Information provided by:
Dr. Graham Forbes
Faculty of Forestry and Environmental Management at UNB
Last Update: May 7, 1998
This document: http://www.unb.ca/web/forestry/centers/cwru/soe/chapter3.htm