GREATER FUNDY ECOSYSTEM RESEARCH PROJECT

UNB Faculty of Forestry and Environmental Management

State of the Greater Fundy Ecosystem

The State of Terrestrial Ecosystems

Stephen Woodley 1 and Stephen Flemming 2
1 Natural Resources Branch - Parks Canada, Hull, Que. K1A 0H3
2 Gros Morne National Park, P.O. Box 130, Rocky Harbour, NF A0K 4N0

Humans have been part of the Greater Fundy Ecosystem (GFE) for perhaps 15,000 years. It is now established that human populations significantly modified natural ecosystems and plant and animal populations during that period. However, there is only good evidence of intensive use of the terrestrial ecosystems of the GFE for about 250 years. During this period, terrestrial ecosystems have been modified and in many cases degraded. These modifications have manifested themselves by changes in forest composition and structure, species loss, the introduction of exotic species and the fragmentation of the landscape into small forest stands. More importantly the trend is toward increasing intensification in land use.

CHANGES IN SPECIES COMPOSITION

One of the single greatest threats to the integrity of an ecosystem is the loss of native species. Perhaps the next most significant threat is the introduction of exotic species, especially if they are highly invasive in nature. This combination of native species loss and the introduction of new species can result in significant changes in biodiversity. Along with this change can also come changes in ecological function.

Species composition changes in the GFE were reviewed earlier in this volume (Chapter 3). In terms of large-scale impact, the loss of the Gray Wolf, Eastern Cougar, Wolverine, and Woodland Caribou may have been very significant. These mammals represented the three largest predators in the system and a very important large herbivore. Although little data exist, it is very plausible that the loss of these species has resulted in significant vegetation changes, at least in terms of relative abundance and distribution. By losing the predators, the herbivorous species on which they preyed would have increased in numbers, potentially over-grazing parts of their range. Likewise, the loss of the Caribou may have also resulted in altered grazing patterns, in this case due to a loss of grazing. While the exact effects are unknown due to the lack of historical data on wildlife populations and vegetation, it is fair to say that the loss of large-sized mammals that have very large home ranges, can significantly alter an ecosystem (Meffe et al., 1994).

In addition to the loss of these potentially keystone species, numerous other species losses have also occurred in the terrestrial ecosystem. Extinct species include Sea Mink, Eskimo Curlew, Passenger Pigeon, and Labrador Duck. Extirpated species include Fisher, Marten, Peregrine Falcon, Spruce Grouse, and Northern Leopard Frog as well as 20 species of plants. Indeed, two additional species of bog plants, Magenta-Pink and Snakemouth may have become extirpated from Fundy National Park in the last decade (Clay and Richard, 1993). Species loss appears to be a significant and ongoing process in the terrestrial ecosystem.

Ecosystems can also be altered by the addition of species. Invasive introduced plants do not have to "conquer" a habitat to pose a significant threat. Invasive plants can also out-compete rare plants and rare plant communities (Meffe et al., 1994). These changes are less obvious, but equally important. In this instance, we may not necessarily see a decrease in biodiversity, but rather a change in species composition.

This change in biodiversity may also be occurring among the large mammals. While a new large carnivore/ herbivore relationship may be establishing itself between White-tailed Deer and Coyote, it is important to note that this relationship is distinctly different from that of the historical past. Coyote and White-tailed Deer are very different animals from the Gray Wolf and Woodland Caribou, both in terms of their life history and ecological role. Moreover, without the Cougar and Gray Wolf, the Moose has no significant predator. Today, Moose numbers are largely dictated by hunting and by Deer numbers through the indirect effects of the Brainworm. The incidence of the Brainworm parasite tracks the abundance of White-tailed Deer, and while harmless to the Deer, it can be fatal to Moose.

With the disappearance of traditional large predators
in the GFE, such as the Wolf and Cougar, Moose
numbers have been largely determined by hunting and
the Brainworm parasite (Photo: Fundy NP).

It is clear that there have been significant changes to the terrestrial ecosystem of the GFE. These changes have long been recognised, and efforts have been made to reintroduce some key predatory species, namely the Fisher, Marten, and Peregrine Falcon, in an effort to begin to re-balance the system.

The efforts to introduce these species, which were detailed in Chapter 3, can teach us two lessons. First, there is an element of luck to the whole process. The success of the Fisher reintroduction with only 16 animals is most fortunate. Usually, much greater effort must be exerted to re-establish a population. In contrast to the Fisher reintroduction, the Peregrine Falcon reintroduction was a huge effort to captively breed and hack (slowly reintroduced from cages at release sites) 178 birds in order to re-establish a breeding population of just six pairs of birds. The second lesson is that a reintroduction has little chance of success if the ecosystem to which the animal belongs is significantly altered. This is the most plausible explanation for the lack of success for the Marten reintroduction. Despite the extensive effort exerted to make the program a success, it appears that the diminished habitat quality and quantity may be ultimately limiting the population. In short, once a species is extirpated from an area, it is difficult to re-establish it. Moreover, if the habitat is degraded in the interim, the prospect of a successful reintroduction may be substantially reduced.

CHANGES IN FOREST COMMUNITIES

The exact composition and structure of the forests of the GFE prior to European settlement is unknown. Still, efforts have been made to determine potential forest cover based on ecological land classification (Zelazny et al., 1997), as well as to identify remnant forest community types (MacDougall and Loo, 1996). Considered together with present-day, forest cover data, these studies can tell us much about potential changes in forest communities. The following summarises these changes (additional details can be found in Chapter 3).

Based on the analyses of Zelazny et al. (1997), MacDougall and Loo (1996), and Lutz (1997), it is clear that spruce and fir are more abundant today than they have been in the past. This appears to be largely due to abandoned farmland growing up as White Spruce, coupled with intensive forest protection measures aimed at suppressing insect infestation and wild fire. Natural disturbances such as Spruce Budworm outbreaks are an important limitation for spruce and fir, so it is not surprising that large-scale insecticide spraying has enhanced the prevalence of these species over time. But another factor is also contributing to the prevalence of spruce. Mixed-wood stands are being actively converted into monoculture coniferous plantations, so that the next pass on these lands will be more productive from a fibre perspective. Largely being carried out on Industrial Freehold and Crown Lands, the most frequently planted tree species in these plantations are Black Spruce, Jack Pine, and Norway Spruce.

Several formally significant communities now only occur in remnant patches. These include the Hemlock slope, Pine-Oak, wet Cedar, coastal ravine Red Spruce, Sugar Maple-White Ash-Ironwood-Beech, and the Silver Maple-American Elm alluvial bottomland forest community types. These communities became rare due to two driving forces: agriculture and forestry. Some of these communities are characteristic of soil types much in demand for agriculture. Wet Cedar forests and bottomland communities were cleared and drained to take advantage of soils conducive to growing clover and hay, respectively. Other communities were specifically harvested for their valuable timber. Hemlock and Red Spruce were used as saw-logs and White Pine was heavily harvested for the production of ship masts. Many of these communities now only occur in small highly isolated patches. Associated plant and animal species are becoming rare or are locally extirpated.

Old-growth forest, regardless of community type is becoming increasingly rare in the GFE. This is especially true for coniferous stands that are being intensively managed, primarily for the pulp and paper industry. For example, only about 4% of coniferous stands in the Greater Fundy Ecosystem are classified as "overmature", far lower that the long term historical average for such forests of about 30%. Older aged communities are critical for the conservation of biological diversity because it is only in old age that structural complexity can fully emerge. This complexity is characterised by substantial amounts of coarse woody debris, both standing and in various states of decay on the ground; multiple canopy layers; uneven age structure; and gaps in the forest canopy (if the stand type is gap replacing). This complexity is the key to the creation of micro-habitat types that can often be unique to old-growth stands. These habitats in turn give rise to specialized species assemblages. While only some old-growth communities harbour high species richness, almost all possess unique and dependent species. In the GFE, old-growth stands constitute preferred habitat for species such as the Marten, Pileated Woodpecker, and the Northern Flying Squirrel.

Anthropogenic plant communities such as fields, abandoned apple orchards, clear-cuts, and road sides are significant components of the present day GFE landscape. Agricultural fields and crops, and apple orchards may not constitute wildlife habitat in the traditional sense, but there is no doubt that they are important plant communities, at least seasonally. For example, Black Bears and White-tailed Deer make seasonal use of blueberry fields and wild apple orchards in the late summer-early fall (see Forbes et al. case study, this volume). Similarly, recently cut areas and road sides may also offer berries at certain times of the year. However, these communities are not always benign or positive. Crops can attract wildlife but also put it into direct conflict with the agricultural industry, leading to the destruction of animals. Furthermore, while some wildlife species may see clearcuts and road sides as opportunities, others may perceive them as partial or even complete barriers to movement across the landscape, as is the case for the Northern Flying Squirrel (Bourgeois et al., In prep).

CHANGES IN ECOSYSTEM FUNCTION

The changes that have occurred in the terrestrial ecosystem in the last 200 years have been substantial. Change has occurred at the species, community, and landscape levels, and in all likelihood, though not evaluated, at the genetic level as well. Biological systems can be very resilient to change. The question that remains to be answered for the terrestrial ecosystem is this: has the system been degraded to the point that ecosystem collapse is imminent? The Northern Flying Squirrel provides an interesting glimpse into this critical question.

The Flying Squirrel is an arboreal rodent that moves through the forest by gliding. Only active at night, this species is dependent on older forest characteristics for its survival (Mowrey and Zasada, 1984; Rosenburg and Anthony, 1992; Gerrow, 1996, this volume). This dependence is in part due to its primary food source, underground fruiting fungi. Termed hypogeous mycorrhizal fungi, many of these species form obligate mycorrhizal associations with woody plants (Maser and Maser, 1988), facilitating for the plants critically important nutrient absorption from the soil (Maser et al., 1978). As hypogeous fungi have no means of releasing spores through the air (Maser et al., 1978; Kotter and Forntinos, 1984; Maser et al., 1985), the activities of mycophagists, such as Flying Squirrels, provide the only mechanism for spore dispersal. In the GFE, the Flying Squirrel is by far the most significant mechanism for the dispersal of hypogeous mycorrhizal fungi (Bishop, 1995; Gerrow, 1996, this volume). Hence, given the fundamental relationship between hypogeous mycorrhizal fungi and woody plants, including trees used in the forest industry, one can make an argument for the Northern Flying Squirrel as a keystone species of the terrestrial ecosystem of the GFE.

If the Northern Flying Squirrel is indeed a keystone species, as it appears to be, its demise could trigger a collapse in the terrestrial ecosystem. In this case, the process could go something like this. With the loss of the Flying Squirrel, spores of hypogeous mycorrhizal fungi would be poorly dispersed. As a consequence, over time, fewer woody plants may achieve a symbiotic relationship with mycorrhizal fungi resulting in diminished vigour for some species of plants. These plants would then be more susceptible to being out-competed and hence, over time, new forest communities would emerge resulting in large-scale faunal change. While this scenario is highly speculative, it is clear that the loss of the Flying Squirrel could have far reaching consequences.

Less speculative is the potential loss of the Flying Squirrel over the next few decades. As mentioned above, the species is dependent on older forests. Yet older forest stands are becoming increasingly rare in the GFE. Moreover, these remnant patches are becoming increasingly isolated from one another. Habitat loss and forest fragmentation can separate populations into smaller isolated or semi-isolated habitat patches. If connections are inadequate, impeding movement or dispersal of animals between habitat patches, then populations can become isolated (Merriam, 1991). Small isolated populations are more susceptible to extinction (Fahrig and Merriam, 1985; Lefkovitch and Fahrig, 1985; Merriam, 1991; Lacy, 1996).

Studies conducted on the Flying Squirrel in the GFE indicate that typical forest harvest landscapes such as clear-cuts, select-cuts, and young regenerating stands constitute barriers to movement for the species (Bourgeois et al., in prep). That this is starting to impact at the population level is indicated by the finding that the relative abundance of Flying Squirrels in the fragmented forest surrounding Fundy NP was only one-third of that in the Park (Flemming, Unpublished data). If the forest continues to be intensively harvested creating even smaller forest fragments, the Flying Squirrel may not survive. The implication of losing this and other potential keystone species is alarming.

CHANGES IN TERRESTRIAL LANDSCAPES

The rate of change in the Greater Fundy Ecosystem was analyzed using a change detection from satellite images. A 1974 MSS (multi-spectral scanner) image was compared to a 1993 TM (Thematic Mapper Image). The results are shown below at three landscape scales.

Figure 5.1 shows the changes that have occurred in a large section of southern New Brunswick in an area of 12,500 km2. In this map, fully one-fourth or 25% of the entire region has undergone a substantial change in the last 20 years, mainly from forestry which accounts for 73% of all changes. Other significant land use changes resulted from agriculture (9%). There was also a considerable amount of land abandonment and this accounted for 16% of land use change.

Figure 5.1. Satellite image detection of 20 Years of landscape change in
an area of 12,500 km2 surrounding Fundy National Park.

The issue is shown at a smaller scale in Figure 5.2. This is an area of 845 km2 (638 km2 outside the park) immediately surrounding Fundy National Park. At this scale the rate of change is even more evident again dominated by forest harvest as a change agent. Outside the park, 96% of the land use change in the last 20 years has been from forest harvest. The other changes were minor and included land abandonment (0.7%) and farm expansion (2.2%). In total this impacted 32% of the landscape. Such a rate of change is unprecedented in the history of the area. The available conifer and mixed-species forests have been cut, leaving an age class structure that is dominated by young forests.

Figure 5.2. Satellite image detection of 20 Years of landscape change
in an area of 845 km2 surrounding Fundy National Park.

Within the park, the rate of change and the type of change has been completely different. In total the rate of change was low, with only 6.7% of the area within the park detected as changed over a period of 20 years. Also different was the type of alteration, with the majority of the change coming from Spruce Budworm (73% of all changes). The remainder was due to regenerating old fields and cuts within the park.

FRAGMENTATION OF TERRESTRIAL LANDSCAPES

Associated with the very large rates of change in the landscape of the Greater Fundy Ecosystem are changes to the structure of the landscape. With intensive forest harvest and a high density of road, the landscape becomes fragmented into smaller patches of habitat. Fragmentation has been called the greatest worldwide threat to forest wildlife (Rosenburg and Raphael, 1986) and the primary cause of species extinction (Wilcox and Murphy, 1985). In the GFE, fragmentation was measured as (1) the area of distinct patches of vegetation that were either not impacted by human activities or had recovered from previous human disturbance, (2) the degree of isolation of forest habitat from developed edges, and (3) the distribution of the size classes of remnant patches of forest. Data presented here are from 1988.

Fragmentation was measured by using the geographic information system SPANS to isolate all patches of relatively undisturbed forest from developed areas or areas that had the forest cover removed. These developed areas occurred as a wide range of land-use classes including; (1) clear-cuts and plantations of less that 10 years of age; (2) all forestry staging areas; (3) roads of all types; (4) parking lots; (5) agricultural fields; (6) lawns and golf courses; and (7) urban sites. Buffers were created on both sides of the developed edges at distances of 100 m, 250 m and 500 m and the areas associated with each zone were calculated (see Woodley, 1993). Finally the areas of remaining forest interior were calculated, along with their frequency distributions. Calculations were done on the GFE’s Intensive Study Area (ISA) and then subdivided into inside and outside of Fundy National Park.

The map of the fragmentation categories created by buffering on each side of the developed edge is presented in Figure 5.3. The area values for each map class are given in Table 5.1.

Figure 5.3. Map of fragmentation caused by human development
in the Intensive Study Area (ISA)

Table 5.1. Fragmentation classes in the ISA, measured as the distance from a developed edge.

Of the entire ISA, only 20.5% remains in the forest interior class 1 (greater that 500 m from a developed edge). The value rises to 35.4% if the forest interior class is considered to begin at 250 m and 50.1% if the forest interior class is considered to begin at 100 m. No matter which value is selected, it is clear that the system is highly fragmented and forest interior habitat is greatly diminished because of human development

An indication of the degree of separation or isolation of the remnant forest patches can be seen in Table 5.1, by examining the class 5 - 8 buffers that extend into the developed areas. Only 0.1% of the total area is in class 8 (greater that 500 m into a developed area) and only 4.1% is in the combined classes of 6, 7 and 8 which collectively are the sum of areas greater than 100 meters into a developed area. Thus, greater than 95% of forest patches are not separated by more than 100 m from each other.

A comparison of the degree of fragmentation inside and outside the park boundary is given in Table 5.2. There is a dramatic difference in the degree of fragmentation inside and outside of Fundy National Park. Inside the National Park, 60.8% of the total area is in the class 1 of forest interior of greater than 500 m from a developed edge and only 5.2% of the park is in classes 5-8 or developed areas. Outside the National Park, only 10.7% of the total area is in the class 1 (forest interior greater than 500 m from a developed edge) and 29.5% of the external lands are in classes 5-8 (developed lands).

Table 5.2. A comparison of fragmentation classes inside and outside the Fundy National Park boundary.

The average patch size for all the class 1 forest interior patches in the Greater Fundy area is 2.04 km2 (n= 112). The frequency distribution of these class 1 forest interior patches is presented in Figure 5.4. The figure illustrates the small size of the remnant patches of class 1 forest interior in the Intensive Study Area. Fully 86.3% of the forest interior patches are in the size category of less than 0.5 km2 (50 hectares).

Figure 5.4. Frequency distribution of the number and size of forest interior patches
greater than 500 m from a developed edge in the ISA, 1988.

There are only five patches in the largest size category of greater than 10 km2 and three of these are found inside Fundy National Park.. These five large patches make up 35% of the total of class 1 forest interior. Small patches of less than 50 hectares have been shown to be limiting to a range of species including forest passerine birds and woodpeckers (Rolstad, 1991). Loss of species in isolated small patches can occur in a relatively short time. Five forest-interior bird species were lost in a 23 hectare forest patch in Connecticut, U.S.A. in only a 23 year period, likely due to fragmentation (Rolstad, 1991).

The ISA is highly fragmented by human development, with the majority of the fragmentation outside the park border. The remaining forest interior patches are small and only five large patches of greater than 10 km2 are left on the landscape. The impact of this fragmentation on wildlife populations is extremely variable, but it is well known that some species are more sensitive than others. The impact of fragmentation on populations of Marten has been calculated to be severe. It is probable that this population will become extirpated simply because of habitat fragmentation (Woodley, 1993).

Patch size has been shown to be an important predictor of the presence of Fisher, Pileated Woodpecker and Sharp-shinned Hawk in Douglas-fir forests in northern California that were fragmented by clear-cutting (Rosenburg and Raphael, 1984). All three of these species are found in the Greater Fundy Ecosystem’s ISA. Pileated Woodpecker presence fell dramatically in remnants less than 20 ha, Sharp-shinned Hawks in remnants less than 50 ha., and Fishers in remnants less than 100 ha. (Rosenburg and Raphael, 1984). The majority of the remnant patches in the ISA are less than 100 ha.

Distance between remnant patches is generally less than 100 meters. The impact of such isolation is unknown and will certainly vary between species. However, even a separation of 100 meters may isolate some sensitive populations. Agricultural fields of 100 meters in width have been shown to be a barrier to dispersal for small organisms such as invertebrates (Mader, 1984) and some species of birds (Saunders and ReBeira, 1991). The impact of isolation of amphibian and reptile populations is unknown but may be highly significant (Verner, 1986). It is likely that clearcuts will not isolate forest patches the same way as agricultural fields.

In conclusion, the Greater Fundy Ecosystem is a highly fragmented system and the degree of fragmentation is likely affecting the viability of sensitive species.

FUTURE TRENDS

It is always difficult, perhaps impossible, to predict the future. The simplest way is to project present trends into the future, realizing that such a practice is full of untestable assumptions and pitfalls. However such a projection is probably realistic in the short term, meaning the 10 to 20 year time horizon. Moreover, there are few other practical alternatives

It is unlikely that there will be significant changes in the permanent human population of the region. Population change from 1971 to 1996 increased 16% in the Southern Uplands Ecoregion (see Chapter 2), with a decrease of 4% in the coastal strip of the Fundy Coast Ecoregion. However the transient summer population in the Fundy Coast Ecoregion is five times the recorded permanent population. It is expected these trends will remain stable in the next 10 years with an overall annual growth rate of 0.46% (Statistics Canada). There is some shift in the type of growth throughout New Brunswick with an increase in the non-farm rural population. Over the same period of 1971 to 1995, the annual growth rate of this sector has been 1.5%. This trend has been seen throughout much of North America with the rise of home business and increase in electronic communications such as the internet. This trend may actually increase.

Tourism is now the world's largest industry, with 592 million international arrivals recorded in 1996. By the year 2010, the annual world income from tourism is expected to top $1500 billion (People and Planet, 1997). Tourism is an important, but relatively small industry in the Greater Fundy Ecosystem. Visitation to Fundy National Park has been relatively stable over the last 10 years with approximately 235,000 annual person visits. Currently there is development of a Fundy multi-purpose trail for hiking, bicycling and snowmobiling between St. Martins and Moncton. In addition there is currently the development of a scenic coastal road between Saint John and the northwestern tip of the Park. Both of these initiatives are expected to significantly increase tourism visits to the area in the 10-20 year horizon.

Forest harvest is showing an increasing trend toward mechanization and intensification worldwide and this holds true for the Greater Fundy Ecosystem. On New Brunswick lands, post harvest plantations have increased from an annual establishment rate of 1,000 ha per year in 1972 to approximately 8,000 ha per year in 1995. Similarly stand tending (such as pre-commercial thinning) have increased from approximately 0 ha per year in 1972 to an annual rate of 25,000 ha per year in 1995. There is also a strong trend toward utilization of a wider range of species, especially tolerant hardwoods. From 1991 to 1995, hardwood utilization in the province has grown substantially, increasing over 50% to 2,241,157 m3 in only four years. Hardwood harvesting has had the greatest growth on owner freehold and on crown licenses. Much of the hardwood in the province has been allocated for harvest.

In summary, terrestrial ecosystems have been significantly altered over the last 250 years and the rate of change appears to be increasing rather than decreasing. There appears to be a continual loss of species from the system in conjunction with habitat loss and fragmentation. The main drivers of this change has been intensive forest harvesting and associated activities.

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Last Update: May 7, 1998
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