GREATER FUNDY ECOSYSTEM RESEARCH PROJECT
UNB Faculty of Forestry and Environmental Management
State of the Greater Fundy Ecosystem
Ecological Magnets and Black Bears
in the Greater Fundy Ecosystem
Graham Forbes1, Derek Johnson2, Edouard Daigle3 and Paul Chamberland3
1 Sir James Dunn Wildlife Research Centre, University of New Brunswick,
Fredericton, N.B. E3B 6C2
2 Faculty of Forestry and Environmental Management, University of
New Brunswick, Fredericton, N.B. E3B 6C2
3 Fundy National Park, P.O. Box 40, Alma N.B. E0A 1B0
|A potential conflict exists in Fundy National Park (Fundy NP) as to whether apple trees in the Park should be eliminated in order to rehabilitate native biodiversity. The issue that could be affected is the maintenance of the Black Bear within the Park. Black Bear is a species which uses apples as a food source in the fall. A central question is the effect on the black bear population from a potential elimination of apples trees within the Park. If it can be proven that bears use the apple trees as a food source, the trees may be protected and managed for as a critical wildlife habitat beneficial to the bear population.
The primary goal of the study was to assess the effect that apple trees in Fundy NP are having on Black Bear feeding patterns. Bears need to develop a reserve of fat in order to survive the winter months until late spring when new food sources appear (Lynch, 1993). Considering the lack of hard mast food sources (e.g. beech nuts, hazel nuts) in much of the region, it is possible that apples could be a valuable food source for bears during this time.
Black Bear (Photo: G. Forbes)
Apple trees near the entrance to Foster Brook Trail,
Although apples are abundant, they do not contain any fat (Jansen et al., 1990). As such, it was necessary to determine if and why the bears fed on apples. A possible theory was that the bears ate the apples for their high energy content. This would allow them to place all fat consumed in reserve for the winter season.
A second goal was to identify alternative food sources if the apples were not sufficient to meet bear fat requirements. There are several sources of food in and around the Park. The problem was to identify ones that contained the quality and quantity of nutritional values that the bears required for their winter sleep. The main criteria for the food source was that it had high fat content.
A third goal was to use this information to make recommendations for the management of apple trees in Fundy NP.
Twenty-three bears were radio-collared and monitored in Fundy NP and the ISA from May to October, 1994, and 1995. Radio-collared bears were tracked by ground and aerial teams and their location was plotted on 1:5000 topographic maps. The bears were monitored daily during the summer and early fall months (June - September) and weekly or biweekly in the late fall (October - December).
The locations of apple trees within Fundy NP were determined from ground surveys in the fall of 1996. Information recorded about the apple trees included condition, approximate height, productivity of apples, and sign of bear and other animal presence. The conditions of the trees were determined by visual assessment which focused on the amount of decay, including the condition of the bark and foliage. Apple tree productivity was determined by the percent of apple coverage of the tree canopy.
Further information such as signs of bears, other wildlife, bait stations and general vegetation coverage were recorded during ground surveys. Signs recorded in the fall of 1996 included claw marks on trees, track, paths and trails, and scat. Scat samples were examined on site for evidence of apple consumption.
Aerial photos, cover-type maps and ground surveys were used to identify new food sources for the bears in the Park. Aerial photos and cover-type maps were used to identify suitable conditions for the likely production of large quantities of soft and hard mast food sources (fruit and nuts).
Forest Units Algorithms (FUNA) information provided by Fundy National Park was used to identify the main types of areas that could contain the best, or the highest, potential for soft or hard mast provider species during the fall period (August - November). The most plentiful or suitable land types were old fields or clearings (Class 1), hardwood forest (Class 4) and mixed forest (Class 2). Mature softwood forest areas with high crown closure (Class 3) were also found to contain some edible vegetation but in lower quantities.
The 1996 ground survey showed that apple trees were restricted to a few isolated areas. The areas with the highest apple tree populations were at Point Wolfe, Herring Cove, Micmac, the golf course, Foster Brook, and near the branch-off of the road to Herring Cove (Figure 1). The majority of apple trees in these areas were deteriorating but still producing crops of apples. The most productive area for apples was the golf course. The majority of the apple trees around the golf course were in very good condition because they had been maintained for aesthetic purposes. Although the golf course area contained an abundant source of apples, no bear signs were noted.
Figure 1. Areas of high apple tree concentrations within Fundy NP.
The collaring data collected in 1994-95 suggests that several bears appear to use or live in the area of the apple trees (Figures 2 and 3). Some of the bears are resident to the area all year and would be expected to be associated with the apples. Several males with home ranges > 200 km2 spent much of the fall in the apple areas of the Park instead of the areas outside the Park. These external areas were most commonly used in spring and summer.
Figure 2. Bear distributions within Fundy NP in fall 1994.
Figure 3. Bear distributions within Fundy NP in 1995.
During the ground surveys, about 60 bait stations were discovered in a 5 km area outside the boundary of the Park (Figure 4). Bait stations were usually located within 200 m of a road prior to and during hunting season. Roads of various types (highway, paved, graded and logging) run in a network around the Park. Discussions with local residents suggest that the actual number of bait stations around the Park may be between 60 and 200. No bait stations were found within the Park itself. Radio-tracking suggests that bears use these bait stations frequently. The old, outdated food used at these stations (e.g. donuts) may be beneficial to wildlife because it provides large quantities of fat and sugar. It is probable that bait stations make up the bulk of some bears' diet during the late summer and fall.
Figure 4. Locations of known bait stations around Fundy NP.
It was estimated that there are about 11,408 ha of productive land (i.e. land that is conducive to the production of food for bear) in the Park. Apple trees are found on less than 100 ha of this productive land. Assuming that alternative food sources provide less than 1 m3/ha of soft and hard mast within the Park and apple trees provide about 10 m3/ha of soft mast (apples), it seems likely that sufficient alternative food could be found by the bears to replace what they could obtain from the apple trees. The alternate food source would also consist of some foods that are higher in fat than the apples (animals and nuts).
Food sources that are widely distributed and in low concentrations require more time and energy which may outweigh the amount of energy consumed. Foods found in large concentrations require much less energy consumption and maximize the amount of energy acquired. Both the apple trees and bait station provide an easily accessible and plentiful supply of food during the fall. This results in lower energy expenditure by the bears in searching for food. Apples also produce large amounts of sugar which may contribute to an abundance of energy to perform other activities. It is possible that the bears that frequent the apples trees maintain their fat reserves which they gathered in the spring and summer by exclusively utilizing the energy provided by the apples during the fall. The bait stations contain food which is high in fat and can be stored for the overwintering period.
If apple trees were removed from the Park, the remaining food sources, with the exception of bait stations, would be widely dispersed. Bears would have to travel longer distances and spend more time scavenging to attain sufficient food to survive. As well, the increased use of the numerous bait stations outside the park would increase the amount of bear mortality.
The results of the radio-collar tracking indicate that bears fed mostly on food sources found in large concentrations. Both apple trees and bait stations provide large concentrations of food during the fall and are the two most frequented areas by the bears. Should the apple trees be removed, it is assumed that the bears that frequented the apple trees will move to the areas of the bait stations which are next largest sources or concentrations of food. They may also eat more meat from wildlife, scavenge local dumps and frequent camping areas and homes. Bears that frequent areas outside of the Park are also at a higher risk of being killed by hunters or poisoned by pollutants or other substances thrown away at dumps or bait stations.
It was determined that sufficient food resources are available for the black bears in the Park should the apple trees be removed. The problem is that bears are attracted to high concentrations of food instead of evenly distributed food. This can result in the migration of bears out of the Park and to areas of high food concentrations (bait stations) and therefore reduction of the bear population in the Park. The migration of bears to areas outside of the Park will lead to an increase in bear deaths and an overall decrease in black bear populations in the area.
IMPLICATIONS FOR MANAGEMENT
It is concluded that if Fundy NP wishes to decrease the mortality rates of bear using the Park then apples should remain part of the Park vascular flora.
It is recommended that the Park integrate an apple tree maintenance program that would improve the condition of apple trees. The condition of apple trees may be improved by pruning, thinning, fertilizing and pest control. Improving apple tree conditions may improve apple tree yield and thus potentially increase the number of bears living in the Park. It is also recommended that measures be taken to prevent the expansion of apple tree territory within the Park. The apple trees represent a historical role in the Park but are not native to the area. The apple trees must be restricted to areas where they possess historical value, such as old homesteads.
Johnson, D. 1997. The effects of residual apple trees on the Black Bears of Fundy National Park. B.Sc. thesis in Forestry. University of New Brunswick. Fredericton, N.B. 58 pp.
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/bear1.htm