Ana səhifə

1998 annual meeting abstracts

Yüklə 44.92 Kb.
ölçüsü44.92 Kb.

Monitoring for Vegetation
Wilderness & Ecological Reserves...
Mercury Pathways & Trophic Interactions
Scale & Predictability in Ecology...
Population Genetic Structure...
Population Dynamics of Atlantic Salmon...
Long Term Effects of Snowmobile Traffic on Vegetation...
Changes in Community Structure of a Boreal Forest...
Fish Communities in Rockweed...
Historical Perspective of Canada Lynx...
Acquisition of Age Data from Big Game & Furbearing Animals...
Avian Migration Monitoring...
Conservation of NF Marten...
Seabird Colony Locations...
Hydroclimatology & Chemistry of Alpine Snow Cover...
Common Loon Breeding...
Status of Rabies in NB...
Managing for Deer Winter Habitat.
Prescribed Fire for Vegetation Management...

Aircraft Activity on the Behaviour of Nesting Osprey...

Monitoring for Vegetation Change in Forest, Peatland, and Tundra Landscapes in Gros Morne National Park

Marilyn Anions, J. Feltham, C. Wentzell, R. Young, S. Flemming, and L. Hermanutz
Gros Morne National Park, Rocky Harbour, NF.
Memorial University of Newfoundland, St. John's, NF.

During the past two years, permanent vegetation sample plots were established in forest, peatland, and tundra communities throughout Gros Morne National Park. These sampling sites will provide measurements of vegetation change through time. Permanent sample plots for forests follow the Newfoundland Forest Service protocol so that the data can be used for multiple purposes (forest management, community change, etc.). Methodologies for peatland and tundra communities follow approaches taken by others in Newfoundland and elsewhere, but were modified to fit the park's circumstances. In this presentation we review the rationale for conducting this type of ecosystem monitoring and the specific methodologies used to ensure that changes can be detected.

Wilderness and Ecological Reserves in Newfoundland and Labrador

Douglas Ballam

Parks and Natural Areas Division, St. John's, NF.

The Wilderness and Ecological Reserves Act (1980) is the strongest protected area legislation in the Province of Newfoundland. Seventeen (17) reserves have been established totalling 4,141 square kilometres. Wilderness Reserves are generally more than 1000 square kilometres and are designed to protect vast tracts of "wilderness". Ecological Reserves are smaller areas which protect special or unique natural features. Large-scale industrial activities are prohibited in both reserves, including forestry operations, mines, road construction and hydroelectric developments. Most traditional activities are permitted unless they are in conflict with the protected feature in question (eg. hunting in a Seabird Ecological Reserve). Current efforts focus on developing a Province-wide plan for a system of Wilderness and Ecological Reserves.

Mercury Pathways and Trophic Interactions in New Brunswick Lakes

E. Barry, and R.A. Curry

New Brunswick Cooperative Fish and Wildlife Research Unit, Biology Department,

University of New Brunswick, Fredericton, NB.
Understanding the movement of mercury through trophic levels is crucial for developing models predicting its fate in natural ecosystems. We sampled primary, secondary and tertiary consumers of 18 lakes and analysed mercury concentrations and trophic position (stomach contents and stable isotope ratios) in southern New Brunswick in 1997/8. Plankton, benthos and bullfrogs were sampled for methyl-mercury and stable isotope analyses in seven of these lakes in 1998 to provide a baseline for inter-lake comparisons. Fish mercury levels vary from 0.02 to 1.09 ug/g, large differences in mercury concentrations are found both within and between lakes. Relationships between lake morphology, water chemistry, trophic position and community structure (average of five fish species per lake) are considered when comparing the large range of fish mercury levels. This study is the first in-depth look at mercury concentrations in lakes of this region. Examination of the trophic interactions within these lakes will lead to a greater understanding of mercury pathways within lakes and further the development of predictive models of mercury levels in New Brunswick lake ecosystems.

Scale and Predictability in Ecology: The Example of Small Mammal Research
Jeffrey C. Bowman, G. J. Forbes, and T. G. Dilworth.

New Brunswick Cooperative Fish and Wildlife Research Unit, Dept. of Biology, University of New Brunswick, Fredericton, NB.

Many small mammal species are notoriously unpredictable in their habitat relationships. We suggest that this unpredictability is related to a scale issue. Often, small mammal studies are conducted at high resolutions (10s of metres) yet there is a demonstrable relationship between resolution and predictability. At higher resolutions, systems are less predictable. It is possible then, that the traditional lack of spatial predictability in small mammal ecology is an artifact of operational scale choices. We present examples from the literature and a case study of small mammals in northwestern New Brunswick. We demonstrate significant (P < 0.001) inter-annual predictability in the spatial distributions of small mammals on a 5000 ha study grid with a resolution of 1 km.

Population Genetic Structure and the Effect of Founder Events on the Genetic Variability of Moose (Alces alces) in Canada
H.G. Broders, S.P. Mahoney, W.A. Montevecchi, and W.S. Davidson

Biopsychology Programme, Memorial University of Newfoundland, St. John's, NF.

The evolutionary potential of any species is dependent upon its genetic variability. An understanding of the factors that influence loss or gain of genetic variability within a species can help us understand and prevent extinction. One such event that is expected to reduce genetic variation is the founding of a new population from a small number of individuals. Three such founder events have occurred through the founding of moose populations on the island of Cape Breton from Alberta, on the island of Newfoundland from New Brunswick and on the Avalon Peninsula from the island of Newfoundland. In order to determine the effects of these introductions on genetic variation in moose I have examined DNA microsatellite variation at five polymorphic loci in moose samples from throughout Canada, including all source and founder populations.
Canadian moose can be assigned to seven distinct populations: Avalon Peninsula-Newfoundland, Central Newfoundland-Northern Peninsula, Labrador, New Brunswick, Cape Breton, Ontario and Alberta. Cluster analysis shows two distinct groups of populations, one including Alberta and Cape Breton and the second including Avalon Peninsula-Newfoundland, Central Newfoundland-Northern Peninsula, Labrador, New Brunswick and Ontario. These two groups correspond to two recognized subspecies.
Four measures of genetic variability, observed and expected heterozygosity, the probability of identity and the mean number of alleles, show that genetic variability is reduced in all founder populations relative to their source populations. However, genetic variability in the founder populations is in some cases comparable to that in populations that have not undergone founder events. Risks associated with any particular level of variability must be assessed relative to specific populations.

Population Dynamics of Atlantic Salmon in Western Brook, Gros Morne National Park
Valerie Bujold, Jay Dietrich, Rick Cunjak, and Stephen Flemming

University of New Brunswick, Fredericton, NB.

Gros Morne National Park, Rocky Harbour, NF.
Since 1985, recreational fishing has been prohibited in Western Brook and Stag Brook in Gros Morne National Park, Newfoundland due to declining stock size of the Atlantic salmon (Salmo salar) in this system. During the late 1950's, spawning salmon may have numbered as many as 2 - 3 thousand fish per year but in 1985, a fish fence survey indicated that only 200 fish remained. Moreover, underwater surveys in the mid-1990's, estimated an annual maximum of 200 adult salmon. Still, a public perception exists that the salmon have recovered and that a recreational fishery should be allowed. Obviously, before this could be considered, the Park has to first assess the salmon population size and breeding ecology within this catchment. The aim of my project is to quantify the salmon egg-survival in this system, by comparing the number of eggs deposited in the stream (autumn) with the number of young-of-the-year (YOY) surviving to emerge the following summer. The first year of life of the salmon is considered to be particularly critical to population survival in this species. In 1998, adult migration was monitored by a counting-fence at the river mouth, from June until October. The fecundity of each female will be estimated to determine egg deposition using a length-fecundity relationship. The YOY population was evaluated during June and July, by sampling for drifting YOY, and by electrofishing to estimate the resident population of those YOY that have established territories . The seasonal use of different parts of the system by the adults as well as all the counting-fence information (sex-ratio, male length, other species, etc.) are also of interest.

Long Term Effects of Snowmobile Traffic on the Vegetation of a Coastal Plain Sphagnum Bog in Gros Morne National Park, Western Newfoundland
Alain Caissie, K.A. Frego, and Stephen Flemming

University of New Brunswick, St. John, NB.

Gros Morne National Park, Rocky Harbour, NF.
Snowmobiling occurs in Gros Morne National Park, both for recreation and for access to traditional harvesting blocks. The potential environmental impacts of these activities have been identified as a priority issue for the Park. The objective of the project was to document differences in substrate and vegetation properties between the trail and surrounding plant communities. The study was conducted at the Green Point Snowmobile Trail. Ninety-four paired samples were taken along a 2 km section of the trail that ran through a sphagnum bog. Substrate characteristics, plant height, and community composition were measured at each of these paired stations. In terms of substrate characteristics, the snowmobile trail was found to be more flat, deep, and wet than the surrounding plant communities. Mechanical damage to shrub species resulted in mean height being significantly reduced. Community composition was also negatively impacted. Species richness was significantly lower on the trail relative to the undamaged sites, and species composition was also significantly different between the disturbed and non-disturbed sites. After 20+ years of use, the Green Point Trail has been significantly impacted in terms of vegetation profile, height, and species composition. It is also plausible that the hydrological regime of the bog has been altered.

Changes in Community Structure of a Boreal Forest

Following 19 Years of Intense Herbivory by Moose
Kevin Conner

New Brunswick Cooperative Fish and Wildlife Research Unit,

University of New Brunswick, Fredericton, NB.

Browse surveys conducted in 1977 within Gros Morne National Park, Newfoundland were replicated during 1996. Browse use, availability and species diversity indices were compared in 1996 to results of Prescott (1977). Mean pellet group counts from surveys during 1996 were significantly greater than surveys in 1977 and sites located outside park boundaries in 1996 (U = 55.0, P = 0.0001 and U = 8.0, P= 0.017, respectively). In 1996, the mean browsing intensity (4293.9 twigs/site, SE=626.2)(33.9% of available twigs) was significantly greater than that of 1977 browse surveys (395.5 twigs/site, SE=76.1)(4.0% of available twigs). Significant differences (P < 0.001) occurred between proportions of available browse species between 1977 and 1996 at all sites. Species selected by moose in greater proportions relative to their availability in 1977 decreased in availability by 1996 while species not browsed or browsed infrequently in 1977 increased in abundance. Selection of browse species by moose changed with changing availability of forage. Mean indices of species diversity in 1977 were significantly greater than species diversity indices at the same sites in 1996. No significant difference was found between mean indices for 1977 and 1996 low moose density sites located outside the Park boundaries. Data suggest that moose have changed species composition, the

proportion of available browse remaining, and hence will influence future forest successional patterns within Gros Morne National Park.

Fish Communities in Rockweed in the Bay of Fundy
Sean Corrigan and A. Curry.

New Brunswick Cooperative Fish and Wildlife Research Unit, Department of Biology, University of New Brunswick, Fredericton, NB.

The commercial harvesting of Ascophyllum nodosum (rockweed) potentially alters the intertidal architecture influencing fish populations inhabiting the rockweed. The impact on these fish communities cannot be assessed until an inventory of species and a description of their microhabitat use have been compiled. I have surveyed unharvested sites near the mouth of the Bay of Fundy over the course of a year. Traps and nets were deployed in the intertidal zone and fish caught were identified and aged. By means of stomach content analyses, diet choice was described and compared to seasonal prey availability data from the Department of Fisheries and Oceans. I also analyzed underwater video images to quantify the spatial and temporal use of the rockweed beds by fishes. To date, 12 separate species of fish from varying age classes have been noted. Results will provide a critical guideline for assessing the sustainability of rockweed harvesting in the Bay of Fundy.

An Historical Perspective of Canada Lynx (Lynx canadensis) in New Brunswick
Rod Cumberland, Richard Doucette, and Todd Byers

New Brunswick Department of Natural Resources & Energy, Fredericton, NB.

Canada lynx (Lynx canadensis) have occupied New Brunswick's forest for at least the last 300 years, but only since the 1920's have their populations declined (Denys 1672, Novak et al.1987). Canada lynx is designated as a Regionally Endangered Species and thus protected under the New Brunswick Endangered Species Act. In recent years, increased incidental trapping of lynx has attracted more attention toward this species. This report is a compilation of currently available information on Canada lynx in New Brunswick. It is recommended that future research initiatives initially focus on determining relative population size and distribution of lynx in New Brunswick.

Acquisition of Age Data from Big Game and Furbearing Animals Harvested in New Brunswick
Ken Eagle

New Brunswick Department of Natural Resources and Energy, Fredericton, NB.

Seven species of animals are monitored in some detail in N.B. and age data are required from them. Analyses of annual cementum increment on tooth roots is the most reliable indicator of age. Teeth are readily collected but preparation of tooth sections and ageing are usually contracted out to a specialized laboratory. New Brunswick's Fish and Wildlife Branch is doing some sectioning and ageing of moose teeth in house.

Avian Migration Monitoring at Gros Morne National Park
Stephen Flemming, Wanda Maynard, and Ian Warkentin

Gros Morne National Park, Rocky Harbour, NF.

Sir Wilfred Grenfell College, Corner Brook, NF.
In recent years, much concern has been expressed about the fate of neotropical migrant birds. Data from breeding bird censuses, Christmas bird counts, and bird banding stations seem to indicate population declines for several species of birds. Still, sometimes the results from these various censuses seem to contradict one another. It has become clear that a large-scale monitoring network is required to properly record population changes for land birds. In Canada, a migration monitoring network is being established to better detect changes in bird populations and demographics. While a few stations have been running for many years, most stations are in a feasibility assessment phase. At Gros Morne National Park, a pilot study has been conducted to assess the feasibility of Lobster Cove Head as a potential monitoring site for bird populations during southward migration. A preliminary effort made in 1997 resulted in 450 birds being captured by mist-net, representing over 30 species of birds. Encouraged by this initial effort, a full-scale pilot project was initiated in 1998. So far, over 1700 birds have been banded, and usable migration monitoring data have been collected on more than 40 species of birds. It appears that the Lobster Cove Head site intercepts birds during southward migration from Labrador and elsewhere on the Northern Peninsula of Newfoundland. This site has excellent potential to help document population changes for northern waterthrush, blackpoll warbler, mourning warbler, common yellowthroat, black and white warbler, fox sparrow, hermit thrush, Swainson's thrush, Lincoln's sparrow, magnolia warbler, yellow-rumped warbler, ruby crowned kinglet, white-throated sparrow, Wilson's warbler, yellow warbler, boreal chickadee, and yellow-bellied flycatcher.

Conservation of Newfoundland Marten:

Preliminary Results of a 5-Year Study
Brian J. Hearn, Cyril Lundrigan, and Bill Curran

Natural Resources Canada, Canadian Forest Service, Corner Brook, NF.

The American marten (Martes americana) is 1 of only 14 terrestrial mammals native to the island of Newfoundland, and taxonomically is classified as a separate subspecies (Martes americana atrata). Currently, Newfoundland marten are restricted in distribution and occupy only a portion of their historical range despite closure to commercial trapping since 1934. In 1973, the Pine Marten Study Area (PMSA) was created by the provincial government as a Wildlife Reserve for protection of the Newfoundland marten. In 1996, Newfoundland marten were listed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as Endangered. Habitat management for marten in Newfoundland, as elsewhere, has centered on protection of mature and overmature coniferous forest (old growth) and local forest-management planning has required industry to include strategies for the protection of marten habitat. This forest-harvesting requirement (constraint) has coincided with a projected provincial wood shortage and has intensified the conflict. Since 1995, we have been investigating marten ecology and demography on the island, in an attempt to understand the relative importance of forest harvesting in determining marten population dynamics. We are monitoring marten populations on 2 study areas, one within the PMSA Reserve and a second population in an area open to forest harvesting, and recreational trapping and snaring. To date, approximately 91 individual marten have been handled, 85 of which have been fitted with radio collars. We will present our preliminary findings from the first 3 years of this 5-year study.

Seabird Colony Locations and Environmental Determination of Seabird Distribution: Towards a Seabird Breeding Model in the Canadian North

Falk Huettmann and Tony Diamond

Atlantic Cooperative Wildlife Ecology Research Network (ACWERN),

University of New Brunswick, Fredericton, NB.
The breeding season constrains movements of breeding seabirds at sea to the feeding range of their colonies. Non-breeders potentially are dispersed at sea wherever they find food; nevertheless, most of them are found also close to colonies. The location of most major Canadian seabird colonies is well known and we hypothesize that this is the driving force for seabird distribution in summer in the Canadian North Atlantic. This paper investigates the relevance of seabird colony proximity for seabirds at sea, based on the PIROP (Programme Intégré

de recherches sur les oiseaux pélagiques) data base. 21 Environmental data sets for the marine environment from a variety of sources grouped into biological, oceanographical and geographical factors are used in this study. A specific foraging range is drawn around these seabird colonies, and the environmental factors are characterized and analysed for their contribution to explaining the distribution of adults, juveniles and non-breeders. Logistic regression and CART (Classification and Regression Trees) are used to explore the influence of these factors on seabird distribution. The results also allow a modelling approach, which enables an evaluation of the quality and type of seabird colonies in relation to their marine environment, potential food sources and species composition, e.g. seabird richness and colony size.

Hydroclimatology and Chemistry of Alpine Snow Cover on Big Level,

Gros Morne National Park
John Jacobs, Colin Banfield, Chris McCarthy, and Moire Wadleigh

Memorial University of Newfoundland, St. John's, NF.

Gros Morne National Park, Rocky Harbour, NF.
Recognizing the significance of snow cover to alpine ecosystems, we set out to determine its physical and chemical characteristics (depth, density, pH, and concentrations of major ions), as well as seasonal evolution and spatial and interannual variability in relation to the local and regional climate. Of particular interest are the late-lying snow beds:

- How extensive are they?

- How much do they vary from year-to-year and over longer periods?

- As a long-lasting moisture source to alpine meadows and headwater streams, are they also a source of concentrated pollutants?

The project is ongoing, but some interesting results are emerging. At the end of the snow accumulation period, surface temperatures were approaching zero degrees C, although the snow pack was not yet isothermal. Maximum depth of snow beds was 400 cm. The basal temperature was -10 degrees C. Snow and ice samples were taken at 10 cm depth intervals. A profile of pH with depths was developed. Inflections in the pH curve indicate exclusion of ions with ice layer formation. By the end of the snow bed phase in late June, average pH had risen to 5.36, compared with 4.95 at the end of the accumulation period. It appears that pre-melt results in a substantial amount of dissolved pollutants being expelled. This may result in acid shock to nearby waterbodies. It is plausible that airborne pollutants are accumulated in snow beds and then released suddenly into biological communities. The implications of this finding are of concern for the sustainability of tundra communities in Gros Morne National Park.

Common Loon Breeding Success in Oligotrophic Lakes in Newfoundland
Joseph J. Kerekes, Roy Knoechel, and Patrick M. Ryan

Canadian Wildlife Service, Dartmouth, NS.

Memorial University of Newfoundland, St. John's, NF.
Monitoring of breeding populations of Common Loon (Gavia immer) in the Experimental Ponds Area (EPA), south of Grand Falls and Terra Nova National Park, Newfoundland, confirms the suggested relationship between lake size and the occupancy of lakes by residential and breeding fish-eating birds such as Common Loon (Gavia immer) and Common Merganser (Mergus merganser americanus). This pattern was attributed to the quantity of fish produced per unit lake surface area based on the nutrient loading - biological production relationship. In Newfoundland the fish production is very low (0.46 kg.ha-1.y-1 in deep lakes to 1.3 kg.ha-1.y-1 in shallow lakes). Since the food requirement to support and rear one loon chick to fledgling is about 180 kg, then the amount of lake area required to raise a loon chick in Newfoundland would range from about 140 hectares in shallow lakes to about 390 hectares in deep lakes. In the Experimental Ponds Area, it has often been observed that adult loons visit other lakes regularly, presumably to feed. It appeared that, in some cases, territory for a pair of loons included several smaller (<50 ha), adjacent lakes. By contrast in less oligotrophic lakes, with higher fish production in Nova Scotia loon reproduction generally occurs in lakes >40 ha, or <10 ha lakes in eutrophic lakes in Alberta. One 26 ha lake was fertilized in EPA with inorganic phosphorus from 1992 to 1996. During that period a pair of loons successfully nested and fledged young on that lake. When Cole's Pond was no longer fertilized in 1997, a chick was present in July but was no longer observed when the lake was thoroughly searched in early September. That lake did not support breeding loons prior to fertilization.

The Status of Rabies in New Brunswick
Gary Moore

New Brunswick Department of Natural Resources and Energy, Fredericton, NB.

Since 1997 a strain of raccoon rabies has been moving northeastward through the New England states at a rate of approximately 50 kilometers/year and entered Maine in 1994. At the same time there has been a gradual eastward movement of a fox strain of rabies from Ontario into Quebec and Maine. A synopsis is provided on the discussion/ preparation ongoing within the province of New Brunswick regarding the anticipated rabies epizootics (2-4 years) and associated problems. The approach encompasses preventative and educational aspects, as well as a clarification of roles and responsibilities of the various government Departments.

Managing for Deer Winter Habitat: A Stand Level Perspective
Shawn Morrison, Graham Forbes, Tim Dilworth, Stewart Lusk, and Steve Young

New Brunswick Cooperative Fish and Wildlife Research Unit,

University of New Brunswick, Fredericton, NB.
Winter is a critical time for white-tailed deer (Odocoileus virginianus). In response to falling temperature and/or snowfall, deer migrate to wintering areas (yards). These wintering areas allow deer to conserve energy and increase their chance of survival until the following spring. To ensure an adequate supply of deer winter habitat, we must first identify those factors influencing habitat use. Radio-telemetry was

used to determine winter habitat use within a northern yard. The use (or non-use) of a given forest stand was then related to habitat and browse conditions using logistic regression. The likelihood of a stand being used was significantly explained by 1) distance to stands with >50% softwood canopy cover (P<0.001), and 2) the presence/absence of maple browse (P<0.01). Regression trees were used to further examine this relationship and indicated that deer select first for cover within 200 m, and secondly for food sources.

Objectives and Considerations of Prescribed Fire for Vegetation Management

in Terra Nova National Park
Randy Power

Terra Nova National Park, Glovertown, NF

Terra Nova National Park (TNNP) is presently developing a vegetation management plan as part of Parks Canada's ongoing commitment to protecting natural resources and maintaining ecological integrity in Canada's national Parks. An integral part of this management program is the consideration of the role fire has played in shaping various park ecosystems and how to reintroduce this role to an obviously altered ecosystem. With the results of fire history and an understanding of the role of fire in the Boreal ecosystem, several fire related issues are evident. While there is documentary and ecological evidence of fire in the past it appears that it has not been of sufficient severity to renew high density black spruce-feather moss forest which is prevalent in TNNP. These primarily man-made, low severity fires, which do not remove either sufficient organic matter or the competing ericaceous shrub rooting layer, creates many regeneration problems. In addition, when fires have occurred under appropriately dry conditions, aggressive fire suppression has severely restricted the potential for burning to influence forest communities to the extent that they could if left alone.

The objective of an active fire management program in TNNP, therefore is easily defined. It would be to start fires or allow natural fire to burn in order to stimulate forest regeneration. The particular goals for prescription or planned ignition fire would include the following: 1) the removal of a sufficient amount of the duff layer in black spruce forest cover types, 2) the elimination of a significant portion of the ericaceous root layer, and 3) the establishment of a high post fire seedling density. Specifying these goals provides direction for defining appropriate fire weather conditions and ecological conditions for proactive fire use. These goals also provide quantifiable and measurable means for which to test the success of these prescriptions.

In order to initiate an active vegetation/fire management program several logistical, social and ecological realities must be addressed. Fire management zoning must consider the appropriate level of suppression response, the tactics used in suppression, and appropriate fire use prescriptions. In order to achieve the objective of duff removal, sufficient drying has to occur, which translates to summer rainfall below normal levels and subsequently, conditions for extreme fire behaviour. There is no guarantee that fire will create high density forest, as in areas where the organic mat is excessively thick or burning in years with low cone crop. A further ecological consideration is the effect an active fire management program could have on the removal of mature, high density coniferous forest habitat - habitat which is now seen as critical for the continued survival of the endangered Newfoundland marten (Martes martes atrata) in this part of Newfoundland. Other considerations revolve around garnering support from both provincial forestry officials and the public in local communities who currently regard fire in an unfavourable light. Finally, the availability of funding is a constant factor in any undertaking of an active fire management program.
Intensive Aircraft Activity on the Behaviour of Nesting Osprey
Perry G. Trimper, Tony E. Chubbs, Neil M. Standen, Gary W. Humphries

Jacques Whitford Environment Ltd., Goose Bay, Labrador

In response to a potential concern, active osprey (Pandion haliaetus) nests within the Low-level Training Area (LLTA) of Labrador and northern Quebec have been isolated from Low-level Flying (LLF) aircraft by an exclusion zone of 2.5 nm radius (Department of National Defence 1994). The selection of the 2.5 nm distance was arbitrarily proposed without the benefit of relevant research. In 1995, Trimper et al. (1998), examined the exclusion requirement for nesting osprey, through a behavioural effects study of their reactions to intensive jet activity on the Naskaupi River of labrador. Controlled low-level CF-18 jet aircraft overflights occurred at distances ranging from 2.5 nautical miles directly overhead active nests at speeds of 400-440 knots, only when observers were present. Despite maximum noise levels exceeding 100dB and rapid onset rates (26 decibels/second), adult osprey did not appear agitated or startled when overflown. Osprey behaviour (nest attendance, exposure of young or eggs, and feeding and defence of the young) did not differ significantly (P=0.126) between pre- and post-overflights periods. In 1996, a second study was undertaken to determine if repeated uncontrolled overflights would elicit a significant response. Using the same area, experimental nests and presumably the same pairs of osprey, unrestricted flights of jet and propellor military aircraft (F-4, F-16, F-18, Tornado and C-160) were able to train within the vicinity of the study area. Detectable overflight distances from the five active nests varied from directly overhead 60 >2.5 nm. Overflights were permitted without from 3 June 1996 (early incubation period) until the end of the training season. Similar to 1995, observations at these and control nests occurred at two week intervals during June and July coinciding with incubation and early nestling periods. A regional decline in osprey nesting success occurred in 1996, and precluded observations beyond the early nestling period. To maximize the opportunity for detecting overt reactions (i.e. reduced opportunity for habituation) overflights were initiated with individual overflights on 3 June 1996. Background noise level and maximum noise level associated with individual overflights remained similar at each location. However, the Equivalent Sound Level (Leg) values increased (<5 dBA as flight track reporting and field observations confirmed an increase of up tp 11 overflights daily, versus a maximum of 16 per month in 1995. Osprey incubation rates during June 1996 were typically greater than 95% and did not differ significantly from 1995 values (P=0.684). Osprey nest attendance also remained high during this period and did not differ wit 1995. As with Trimper et al. (1998) repeated jet aircraft overflights did not interfere with reproductive activities of osprey through behavioural changes associated with nest attendance. Reactions by osprey possibly influencing nest success (e.g. agitation, temporary nest abandonment), increased in severity in association with slower fixed-wing aircraft, other osprey or raptors entering territories and observers entering/existing blinds.

Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur © 2016
rəhbərliyinə müraciət