State of the Greater Fundy Ecosystem

GREATER FUNDY ECOSYSTEM RESEARCH PROJECT

UNB Faculty of Forestry and Environmental Management

State of the Greater Fundy Ecosystem

Conclusion: State of the Greater Fundy Ecosystem

Stephen Woodley1 and Graham Forbes2
1Natural Resources Branch - Parks Canada, Hull, Que. K1A 0H3
2GFE Research Project, University of New Brunswick, Fredericton, N.B. E3B 6C2

INTRODUCTION

This document contains over 200 pages of detailed information on the state of the Greater Fundy Ecosystem, including information on 24 specific scientific studies. Compared to most other areas on the planet, this area is very well understood. However, any assessment of the state of an ecosystem must be accompanied with some critical caveats. First and foremost, our fundamental understanding of how ecosystems are structured is weak. For example, the basic question of whether an ecosystem is impaired with the loss of a single species remains unanswered. What is the true relationship between structure, such as the number and arrangement of species and ecosystem functions such as decomposition? Although there are insights into the nature of these relationships, hard and fast rules are elusive.

Second, although we may understand many ecosystem functions, our ability to measure most ecosystem variables is limited by our technology and also practical considerations. For example, we are unable to easily measure the rate at which ecosystems are using energy. Because of these limitations, we fall back on cruder ways of assessing condition, based on sets of ecological indicators. In assembling sets of indicators, we attempt to account for ecosystem structure and function and also hope to account for the inherent multi-scaled nature of ecosystems.

Because we live in, and are supported by ecosystems, our assessment of their well-being is tied up in our own desires and demands. We recognize that science does not offer us a completely unbiased and objective set of criteria by which to assess the state of ecosystems. However, neither is science completely silent on the matter. It is important to state our assumptions at the start. Our assessment of the state of the Greater Fundy Ecosystem is based on assessing its ecological integrity. This is defined as:

....a state of ecosystem development that is optimized for its geographic location, including energy input and colonization history (Woodley, 1993).

Such an optimal state means that native species are present at viable population levels and, within successional limits, the system is likely to persist. Ecological integrity is a state in which ecosystem functions and structure are present and operating to support viable populations of native species. Ecosystems with integrity do not exhibit the trends associated with stressed ecosystems, such as an inability to conserve nutrients or overall system retrogression.

PAST ASSESSMENT

Ecological integrity in the Greater Fundy Ecosystem was initially assessed in 1993 (Woodley). This present study is based on a greatly expanded data base and 24 additional research studies. However, there is a very strong correlation of results. The 1993 study was based on assessing a suite of ecological indicators, with the overall indicator set chosen to be 1) sensitive to stress, 2) diagnostic, and 3) relatively easily and reliably measured. The indicator set was as follows (for details on the indicators see Woodley, 1993):

Succession/Retrogression - The reversion to an earlier stage of succession is discussed by several authors as a trend exhibited by stressed ecosystems (Rapport et al., 1985; Schaeffer et al., 1988). Woodwell (1967) noted that pollutant stressors tend to cause changes that are just the reverse of those occurring during normal succession - the communities are simplified, niches are opened and succession begins again. In the case of the 1993 Fundy study, this measure examined the return rate of the main disturbance element, Spruce Budworm, and the average stand age of the budworm impacted forest. The target value was the historical value from the last century.

Loss of native species - Species loss is seen as detrimental to the ecosystem and assumed to be detrimental to ecosystem function. In the case of the 1993 Fundy study, the measure looked at the number of species of mammals lost in the historical period. The target value was no loss of native species.

Invasion of exotic species - It is well established that exotic species can have detrimental impacts on native species. In the case of the 1993 Fundy study, the measure looked at the number of exotic species of vascular plants, measured as a percentage of the overall flora. The target value was no exotic species.

Loss in average body size - This measure takes the mean of male and female body weights for each species and then computes a simple average for all species present. When a species is extirpated from the area, the average changes. This measure is based on the observation that stressed ecosystems exhibit a change in community structure in which the size of organisms would decrease (Odum, 1985; Woodwell, 1967; Freedman and Hutchison, 1980). In the case of the 1993 Fundy study, the measure was of the average body size of all mammal species present in the ecosystem. The target value was the average body size with all native species present.

Reproduction in key indicator species - A change in rate of reproduction of sensitive species is often the first indicator of stress in an ecosystem. In the case of the 1993 Fundy study, reproductive rates of Sharp-shinned Hawks were used, based on available data. The target value was taken from studies in the literature of unimpaired populations and research in Fundy NP.

Ability to retain nutrients - Stressed terrestrial ecosystems have been shown to export large amounts of nutrients, especially calcium and nitrogen, compared to unstressed systems (Bormann et al., 1974; Likens et al., 1978). In the case of the 1993 Fundy study, the ability of the system to retain calcium was assessed by looking at changes in total calcium export from the Point Wolfe River basin. The target value was no increase in the long-term trend.

Landscape fragmentation - 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 case of the 1993 Fundy study, 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. The target value was the historical unfragmented forest.

Viability of populations - The viability of a population can be estimated as a probability, from a set of measures of age-specific mortality, natility, immigration and emigration. Habitat and genetic factors can also be accounted for in the probability estimate. It is necessary to assess the viability of species sensitive to stress. In the case of the 1993 Fundy study, viability estimates were conducted on American Martin populations. The target value was a population of 250 adult American Marten.

Using the above set of ecological indicators, the results from the 1993 Greater Fundy study are summarized below. Table 8.1 data illustrate the situation for the eight ecological variables described in the 1993 study. All the variables are measured as deviations from fixed targets that were set to a reference level of 1. For example, all native species were considered to be important to the species richness measure, so the reference level of 1 means all historical species should be present Deviations from the reference level are deviations from the desired state of ecological integrity.

Table 8.1. A summary of ecological integrity scores from the suite of eight
measures used in the 1993 assessment of the Greater Fundy Study
Area (Woodley, 1993)

In the 1993 study, the largest deviation from the reference level was for landscape fragmentation. The other two measures with large deviations were for succession/retrogression and populations viability (of American Marten). These measures indicate the Greater Fundy study area and Fundy NP show large deviations from reference levels. The measures showed that the GFE has lost a significant degree of its ecological integrity in historical times. This loss of integrity is caused by high levels of human use of the landscape, chiefly for forestry, but also by recreation, tourism and agriculture. The area has lost significant species and many exotic species have invaded. The landscape is highly fragmented and there is evidence of a decline in ecosystem function. Perhaps more importantly, the likelihood of further losses of species is high.

THE CURRENT ASSESSMENT

This assessment of the state of ecological integrity fully supports the 1993 results. If anything, the intense research effort in recent years has pointed out increases in the problems listed in 1993 as well as additional threats to ecological integrity. Below are each of the ecological indicators reported in 1993 and discussion of the new information recorded since then.

Succession/Retrogression - In the GFE, all the disturbance processes are resulting in younger, early successional forests, when compared to historical levels. Epidemics of Spruce Budworm have historically been the main disturbance element in the coniferous forest. These epidemics appear to be increasing in both intensity and frequency. The interval between budworm outbreaks in the New Brunswick/Quebec Acadian forest has decreased from a range of 42-75 years in the 19th century to 19-34 years in the 20th century (Blais, 1983). In New Brunswick, Spruce Budworm populations became epidemic in 1949 and again in 1968, an interval of only 19 years. The number of outbreaks in New Brunswick dropped from three in the 19th century to two in the 20th century. In large scale, intense epidemics, virtually all individual trees of susceptible species are attacked. While individual trees might survive one epidemic, they are unlikely to survive a second attack. Thus the maximum age of spruce trees in areas subject to intense budworm outbreaks should be less than twice the budworm return interval. In the GFE, if recent trends continue into the future, there is little chance of stands of spruce persisting beyond two epidemics, or 39-68 years of age (Woodley, 1993).

The other main disturbance element in the GFE is forest harvest. While this has traditionally been concentrated in coniferous communities, there have been recent and large-scale shifts to deciduous communities. Within the last 20 years approximately 30% of the entire ecosystem has been harvested or otherwise disturbed for forestry roads and other harvesting-associated features (see Chapter 5, this volume). This disturbance rate is equivalent to a 66-year cycle of disturbance. Historically the overall disturbance cycle in the ecosystem would have been 4-5 times as long (Wein and More, 1977).

The disturbances from budworm and forestry are not necessarily additive. A significant portion of the budworm-impacted forest was cut as a salvage harvest. However, taken together, there is a rate of disturbance in the ecosystem that is much higher that the historical rate. The high disturbance rate has led to an overall retrogression in the system and a loss of older aged forest stands, which is a reliable indicator of a decline in ecological integrity.

Loss of native species - Further work has identified a significantly higher number of native species that have been lost to the GFE than previously reported (Forbes et al., this volume, summary Table 3.8, Chapter 3). New information shows high levels of species losses in stream and river ecosystems, most likely caused by log-driving in the 1800's (Clay, Chapter 6, this volume). There is a loss of at least one fresh-water mussel (Dwarf Wedge Mussel) and three species of anadromous fish not longer spawn in Fundy's rivers. The most recent loss was the Atlantic Salmon, which has declined catastrophically in the entire upper Bay of Fundy. The Northern Leopard Frog has not been recorded in Fundy National Park in 10 years and is now considered extirpated. Additional information has allowed the compilation of a list of 20 species of plants that have not been recorded in the GFE since 1960 and are also considered extirpated (Table 3.4, Chapter 3). In summary the GFE has recorded losses of 14 species of vertebrates, one invertebrate and 20 plants. These losses have mainly occurred since the turn of the century and appear to be ongoing. The losses have affected all communities and trophic levels. Collectively they indicate a serious and ongoing decline in the ecological integrity of the ecosystem.

Invasion of exotic species - The current numbers of exotic species that occur in the GFE are summarized in Table 3.8, Chapter 3. In total 153 known exotic species have been recorded, including three mammals, three breeding birds, 132 vascular plants and 15 Lepidoptera. This comprises 17.5% of the total known species in these groups. In addition to these groups, there are key exotic invertebrates such as Beech scale, but this group has not been sufficiently well surveyed to report upon in any comprehensive manner.

The Coyote and the White-tailed Deer are two exotic species that have become important keystone species. Deer populations exert a determining force on vegetation patterns and are in turn probably controlled by Coyotes. To date, there are no serious invasive problems with the 132 species of vascular plants although many species are widespread. Most of these exotic species are found in areas of human disturbance, including plantations (see Roberts and Methven, Table 1, pages 83-84).

There are major impacts from exotics that act as pathogens on American Elm (Dutch Elm Disease) and American Beech tree populations, which are both dramatically reduced. The impact of the virtual removal of Beech mast from the food web can only be guessed at, but Beech mast is a major food source in areas where it is healthy.

In summary, exotic species are well established in the GFE in all communities and at all trophic levels. They have already restructured entire forest communities by effectively eliminating key canopy tree species. Because exotic species exist in high numbers over a range of taxa, they have the potential to make dramatic changes in the future.

Loss in average body size - This measure is unchanged to reported levels in 1993. It was based on the average body weight of all mammal species present and there have been no changes in mammal species richness since 1993. The 1993 (Woodley) study demonstrated a decline in average body weight of 8.2% for all species and 13.9% for native species, an indication of a loss in ecological integrity in the Fundy system.

Reproduction in key indicator species - For this report, reproduction was reported for several species. Following is a table of such species, with reference to healthy levels of reproduction (Table 8.2)

Table 8.2.

The data on reproduction indicate some both good and bad news. The data on Ovenbird mating success indicate fragmentation from forest harvest may not be as severe as that reported from agricultural landscapes. Also tourism pressure, on at least one lake, has been managed to allow successful reproduction of Common Loon. On the other hand, there are major problems with recruitment in Atlantic Salmon. However, this does not appear to be a problem with reproduction, rather a problem with adult and sub-adult survival. Noted reproduction problems in Spring Peepers and Spotted Salamanders in clearcuts are related to a change in the hydrological regimes. This change will likely be temporary.

Overall reproductive rates do not appear to be impaired. Changes in populations appear to be the result of changes in mortality rates and loss of habitat.

Ability to retain nutrients - The 1993 assessment was based on changes in the export of Ca ions from the Point Wolfe watershed. The Point Wolfe River had a significant increase in Ca ion export during the mid 1980's (Woodley, 1993). This was the period when approximately 25% of the watershed was disturbed through intensive forestry. The ability of a system to conserve nutrients is a good indicator of the state of the system. A detailed analysis of the impact of forestry practices on K ion export was conducted for the period of 1972 to 1992, also for the Point Wolfe watershed (Pomeroy et al., this volume, page 157). This study showed elevated levels of K ion export due in intensive forest harvest, scarification and replanting during the years 1975-76. O’Brien and Freedman (this volume, page 89) showed elevated concentrations of several nutrients, including total nitrogen in streams draining clearcuts. Thus, there is a demonstrated relationship between forest harvest and the inability to retain nutrients, which is a decline in ecological integrity. The loss of Ca and K ions impacts the productivity of the Point Wolfe basin, with impacts on the ecosystem and the economic viability of future forestry.

Landscape fragmentation - This indicator is unchanged from reported levels in 1993 as the level of fragmentation has not been re-analyzed. The 1993 study showed the Greater Fundy study area as highly fragmented by human development, with the majority of the fragmentation outside the park border. For example, road densities in the GFE are very high at 0.9 km/km2. Evidence from other regions suggests that a road density of 0.58 km/km2 is associated with losses in ecological integrity (Forman and Hersperger, 1996). The impact of forest fragmentation on wildlife populations is extremely variable, but it is well known that some species are more sensitive than others (see Chapter 5, this volume). Certainly species sensitive to fragmentation, such as the Red-backed Salamander and Flying Squirrel appear to be impacted. The current level of fragmentation is concluded to be affecting the ecological integrity of the area.

Viability of populations - Some populations in the GFE are unlikely to persist in the future, because of the stresses operating on the ecosystem. The probability of American Marten persisting in the system was calculated to be low in 1993 (Woodley, 1993). The tenuous nature of this population was reconfirmed in this volume (see Bourgeois, p. 132 ). Populations of Flying Squirrels also appear tenuous due to loss of older-aged forests and forest fragmentation (Flemming, pers. comm.). Calculations of population viability require detailed understanding of mortality, natility, immigration and emigration, as well as habitat use in a given area. For the GFE, we have only attempted viability analysis for two species. However the fact that populations of two species of mammals have a low probability of persisting is cause for concern. Both are habitat specialists, and their habitat is being altered to an extent that will likely result in their extirpation.

Other Concerns

In addition to the indicators of ecological integrity discussed above, there are a number of additional sources of information that are important to understanding ecological integrity. There has been a significant change in community structure (see Chapters 3 and 5, this volume). Compared to past estimates of the forest, there is a increase in Balsam Fir, Spruce and Poplar and a decrease in Cedar, Beech, Ash, Larch and Hemlock . There has also been a dramatic change in the relative abundance of bird populations. While most of this change is attributable to habitat changes due to Spruce Budworm outbreaks, there is an unexplained decline in many species of birds that migrate to the tropics (so called neo-tropical migrants) (Christie, page 127, this volume). The decline in neo-tropical migrants is found across a wide variety of species, including many species not associated with the Spruce Budworm outbreak. In forest plantations, there is marked change in ecosystem structure, including understory vegetation (Roberts and Methven, page 83, this volume), woody biomass (Fleming and Freedman, page 86, this volume), and breeding birds (Johnson and Freedman, page 92, this volume).

There are both regional and localized problems from toxics and pollutants in the GFE. The widespread problems are from ground level ozone, acidic precipitation (see page 35) and widespread levels of persistent organo-chlorides, such as DDT. The use of herbicides, particularly in plantations, has increased 50% since 1986. The localized problems occur on the Fundy NP golf course greens (page 36), where concentrations of mercury exceed national standards. This is a legacy from years of mercury based fungicide application. There are also very high copper concentrations at the old Agricultural Research Station in the National Park (page 36), left from potato sterilization operations.

Hunting and trapping may be causing adverse impacts on at least two species. Black Bear are heavily hunted around the park through the use of bait stations (see Forbes et al., page 137, this volume). Such an intense harvest selects for large adult males, which are virtually absent from the population. American Marten are at very low numbers in the area and are taken as a by-catch.

IN SUMMARY

Research has shown the Greater Fundy Ecosystem to be heavily impacted, with a demonstrated loss of ecological integrity. More importantly, trends are toward continued loss of ecological integrity as land use pressures intensify. Some of the ecosystem impacts are dramatic. The rivers have only a few of their native fish species remaining, older-aged forest communities are dramatically reduced and the viability of sensitive species is doubtful. The remaining forest communities are highly fragmented by forest roads, clearcuts and plantations. The GFE has recorded losses of 14 species of vertebrates, one invertebrate and 20 plants. This species loss seems to be ongoing. There has been a widespread change of community structure and many community types have been reduced in extent. The primary stressor in the ecosystem currently is forest harvest, although land-clearing for agriculture, and hunting and trapping, have been significant in the past.

The level of ecological impact is surprising, given the area has always had a relatively low population density and functions primarily as a "harvested hinterland". This study demonstrates the impact of only 200 years of human harvest on an ecosystem, done at relatively low population densities.

WHAT CAN BE DONE TO MANAGE FOR ECOLOGICAL INTEGRITY

Given the demonstrated decline in ecological integrity, what can be done to manage the Greater Fundy Ecosystem more sustainably? The area has a great advantage in being part of Canadian Model Forest - The Fundy Model Forest. Land managers have been working closely with the scientists that have contributed to this report, with an aim to manage for ecological integrity. Implicit in this goal is to conserve native biodiversity. The Greater Fundy Ecosystem Research Group has attempted to provide a solution to forest management so that ecological integrity could be maintained and enhanced. That solution is contained in the publication "Forest Management Guidelines to Conserve Native Biodiversity in the Fundy Model Forest" (Woodley and Forbes, 1997)(see Chapter 7 for summary).

The Fundy Model Forest has calculated the impact of implementing the Forest Management Guidelines on the annual allowable cut. If all the guidelines are implemented, the impact is a reduction of approximately 35% of the annual allowable cut. To some this might see high and therefore unacceptable. To others, it is a small amount and not enough of a conservation safeguard. We submit this as one of the only calculations of the economic cost of managing an area to conserve biodiversity. The Greater Fundy Ecosystem Group seeks to provide scientific advice on what is required to manage a landscape on an ecologically sustainable basis. We conclude that the landscape is currently not being managed on an ecologically sustainable basis. We submit that the Forest Management Guidelines presented in Chapter 7 are our best professional advice for sustainable management. Whether or not the cost is acceptable will have to be determined by a larger public.

- Table of Contents

- View case studies

- Bibliography