ENGLISH SUMMARY

Background and Organization

On 8 October 1992 the Norwegian Legislature decided that Gardermoen Airport should be expanded into the new National Airport for Norway. This involved a substantial expansion of the existing airport facilities together with construction of new supply routes and improvements of existing highways. The costs for this project include 14 million NOK for airport construction plus an estimated 3 bil-lion NOK in road projects and 6 bilbil-lion NOK for a new high speed rail line.

Much of this development occurs in the major winter feeding area utilized by 400 - 500 moose. Moose that spend summers in the surrounding upland areas are forced down to the low-lying Romerike plains by heavy snowfall. The migration of moose to this winter feeding area is one of the largest and most complex in the country, with between 500 and 700 moose moving onto the flats every winter.

This migration is necessary to maintain healthy populations of moose in the many neighboring areas normally subjected to large amounts of snowfall. Ancient trapping graves and stone fences indicate that the Romerike migration has been occurring for thousands of years.

In order to obtain baseline data on how moose used this winter range prior to development, and to enable a running exchange of information with the contractors during development a special moose project was established. «The Moose Project for upper Ro-merike» (Elgprosjektet på Øvre Romerike) was a cooperative project among the Environmental Department for the Governor of Oslo and Akershus, NSB Gardermobanen AS (High-speed railroad), and Statens vegvesen Akers-hus (Highway Department) from 1993-95.

Methods

Moose habitat-use and migration routes were mapped with frequent localization of 42 radiocollared individuals, pellet transects and studies of moose browse selection. Browse

selection was measured by following the trails of 46 different moose and recording all tree species available to the moose and those that were actually browsed upon. Browse quality was investigated by measuring the twig dia-meter from every fifth tree browsed by the moose. In addition, moose activity along plan-ned development routes (roads and railroads) and existing roads was registered with weekly track counts (so long as there was snow).

To get knowledge about the amount and distribution of browse on the winter range we constructed a digital map of the area based on CORINE land cover classifications with 5 daa as minimum area size. The foundation habitat data were based on SPOT satellite imagery taken 24 June 1995. Use of the satellite data enabled us to delineate habitat classifications over the entire Romerike Flats (750 km²) and most of the forested highlands to the north and west (1700 km²). The mapped areas encompassed both summer and winter habitats used for a moose population totaling about 1000 animals.

The biomass of browse species were measured by laying out sampling plots (circles with radius depending of forest density) within every habitat type. For bushes we counted and measured the diameter of all new shoots (latest years growth) within each plot. For trees we first calculated the correlation between twig biomass and more easily measure parameters such as: height, diameter at breast height, crown diameter, etc. Biomass of winter feed for moose was then calculated for each habitat type. By combining the biomass measurements with the digital map into a GIS program we calculated the quantity and distribution of winter browse for moose over the entire Romerike Flats.

The barrier effect of the larger traffic arteries on moose migration patterns and the risk of vehicle-moose collisions when cross-ing roads was investigated on E6 through Eids-voll (10,000 cars/day) by frequent control of tracks along this roadway.

To register the condition and productivity of the moose population prior to development we used: production information from hunter-observation data, collection of biologic

mate-13. SUMMARY

rial from harvested animals, and control of the radiocollared animals. This material, collected during the moose hunting season since 1991, was supplemented with data on moose-vehicle collisions, harvest statistics, and slaughter weights from 1985 to 1995.

Results

HABITAT USE, BROWSE CHOICE, AND BROWSE AVAILABILITY

It was not possible to find a clearly controlling factor for the onset of the annual migration onto the winter range or back again onto the sum-mer ranges. However, the amounts of snow on the summer range is considered to be an im-portant factor. The majority of the moose began to migrate towards the winter range in the end of November in 1993-94, while the main migration came 3-5 weeks later in the winter of 1994-95.

During winter the radiocollared moose concentrated in an area just north of the airport (Trandum) and to the west-southwest of the airport (Sogna ravine area). Fourteen of 34 moose (those with enough radio locations to calculate home ranges) used Trandum, 8 used the Sogna area, and 5 were located in the green area along Leira River. There was extensive wandering between the individual browsing areas throughout the winter resulting in large home ranges. Moose cows, forexample, had an average core area (60% of total home range) of 17 km².

Moose pellet transects mirrored the observations of radiocollared moose with the central portion of the winter range showing densities 7 times greater than the southern and eastern portions of Romerike Flats. The Gunhildrud, Trandum, Sogna, and Leira areas were shown to have the greatest winter moose densities on Romerike Flats. The density of moose pellets in the forested areas along E6 was 3.5 times greater on the west side compared to equivalent areas on the east side or areas without wildlife fences along the highway.

The pattern of wandering among different browsing areas was clearly illustrated in the track registrations. The road along the forest edge to the north and west of the central winter browsing area was the only place that have a

into the area). Along all the other roads and planned routes the number of tracks were roughly equal in both directions. This wandering back and forth across roads can be reduced with better planning of the green areas in the upper regions of Romerike Flats.

In the study area moose showed a preference of browse plants in the following order: aspen, willow, juniper, rowan, pine, and alder. Birch and spruce were not preferred. Only willow showed a significant preference in relation to availability. The quantity available of the other species was too small to accurately measure significance. Pine composed 52% of the winter diet for moose largely because of the abundant availability. The largest diameter twigs browsed by moose were in the area around the airport and the smallest in the area around Hauerseter. The Bergermoen and Sogna-ravine areas fell between these two extremes. The twig diameter browsed by moose reflect browsing pressure on the range, and quality of the food, with the largest twigs representing the worst quality.

Radiocollared moose showed no statistically significant preference for any of the classified habitat types. This is probably because the terrain is quite uneven and fragmented into small habitat types and the precision of the radio locations was not good enough to ascertain the exact habitat use. In relation to availability of the various habitats radiocollared moose were found most often in the pine forest habitat types.

Calculations of the distribution of browse resources showed that the forest area between E6 and Vorma/Glomma River (east of E6) had twice as much moose browse as that found on Romerike Flats west of E6. The minimum estimated biomass of winter shrubs available to moose (0.5 - 3 meter high) is 3,000,000 kg over the entire Romerike Flats with 1,500,000 kg being the current years growth (1995).

MOOSE AND TRAFFIC

Investigations of the barrier effect of the larger roadways showed that moose turned around in 40% of the occasions when they came upon E6 (n = 191). This was in spite of the fact that in 63% of the cases the track pattern indicated that the moose knew where it was possible to cross the road. At wildlife sluices, where moose

13. English summary

reflected much stress on the animals part. In 74% of the cases moose made several attempts before they eventually turned around or proceeded over the highway. The bridges over E6 are seldom used by moose (note: all are road or agricultural bridges, no wildlife bridges). Only the largest of the underpasses available were used regularly with good vision to the other side, and large, light openings appearing to be the most important factors.

When moose made attempts to cross the road they were hit by vehicles in 5.2% of the cases.

The traffic density was 10 000 cars/ day.

On all the track routes controlled regularly for fresh sign we mapped special points and stretches of roads that were subjected to particularly many moose crossings. These locations would be an outstanding start point for employing measures designed to reduce the number of moose collisions along existing or planned roadways. A critical factor involved in evaluating the actual measures to be employed along roadways are whether the development occurs within the moose core home range or in the migration route. On Ro-merike Flats most of the road and railroad projects are located central in the winter browsing area, the area where it is most im-portant to complete mitigation measures.

Based on a literature study and investigations along E6 it appears that complete fencing in combination with over- or under-passes is the only mitigation measure that will prevent moose collisions and still avoid creating an unwanted barrier effect. These fauna passages must be shaped and sized such that moose will not reject them.

MITIGATION MEASURES ALONG TRAFFIC ARTERIES (ROADWAYS AND RAILROADS)

Analysis of the planned routes for development of roads and railways identified the following four areas having major conflicts with the moose population:

• The section of high-speed railroad line between the airport and the tunnel entrance at Råholt (8 km) had over 1500 moose crossings in the course of a 20 week winter season.

Seventy-eight percent of the crossings occurred between the airport and State Highway 176.

heavily used winter range mitigation measures must be employed. No particular points stand out in regards to crossing intensity so theref-ore the exact placement of fauna passages can be decided on other conditions

• The planned State Highway 35 between Gardermoen and Slettmoen follows much of the same route as the moose use in their seasonal migration onto the winter range. Track counts indicate that over 300 moose crossings can be expected during the winter. This road has an expected traffic density of 6600 cars/

day after the opening and Gardermoen Airport, and over 9000 cars/day in 2010. It will theref-ore be necessary to employ extensive mitigation measures in order to prevent moose-vehicle collisions and still avoid a barrier effect. A wild-life fence will be necessary along the roadway together with sufficient fauna passages. Four points stand out as optimum places for these passages.

• State Highway 120 will be improved to function as an alternative to E6 for access to the airport from the south. The road crosses through some the of the largest continuous winter range areas. Approximately 125 moose crossings can be expected during the winter concentrated mostly at 3 points. At 2 of these points, where Rv 120 crosses the Sogna and Leira Rivers, moose can be led under the roadway. At the third point a wildlife sluice be set up allowing moose to cross the road on a flat area. In addition will wildlife fences be necessary to steer the moose into all crossing points.

• E6 north of Kverndalen is improved into a 4 lane highway. The section between Kvern-dalen and Hauerseter was the most used cross-ing point prior to development, with 165 crossings registered. With development of a 4 lane highway wildlife fencing must be set up to prevent these moose from coming onto the road. This will press the main migration route to the section of highway between Hauerseter and Dal. Improvements of E6 will thereby necessitate that mitigating measures also be incorporated here. With an expected traffic load of 18,000 cars/day the roadway must be shielded with wildlife fencing. The migration to the winter range east of E6 must be made

passages. Without such mitigating measures this stretch of highway will become a “road of death” for both animals and people.

POPULATION DATA

The population data gathered to date generally indicates no clearly negative developments in the last 5-6 years. However, the slaughter weights of calves has indicated a clearly nega-tive trend. The actual status and productivity of the Romerike moose population will be determined after combining data gathered before, with data gathered after the development projects are finished.

FOLLOW-UP INVESTIGATIONS The goal of the Romerike Moose Project has been to gather data for use in regional manage-ment with an emphasis on moose habitat use and browse selection for the greater Romerike area. In order to evaluate the ultimate consequences of the Gardermoen Airport development follow-up investigations must address the following two questions:

1. Has the Gardermoen development changed the moose landuse patterns in a way that has led to increased conflicts in other portions of the winter range? These conflicts include increased collision hazards (at both existing and new crossing points); serious dam-age to the feed resources of the winter range;

and reductions of the biological diversity of the area.

2. Has the Gardermoen development changed the status of the moose population such that the health and production is reduced.

With respect to the comprehensive investments being made in establishing mitigation measures to preserve diverse ani-mal life throughout the greater Romerike area it would seem only natural to evaluate infor-mation on how these measures worked. This evaluation should be conducted with the idea of adjusting the measures so that they work better and evaluating them for use in other areas.

These questions demand the continued monitoring of radiocollared moose, registrations of how these moose use the constructed mitigation measures, and a

from both the radiocollared moose and from the moose hunts in Nannestad, Ullensaker, Hurdal, and Eidsvoll communities.

On a national perspective moose-vehicle collisions cost 250-300 million kroner per year.

Numerous mitigation measures have been attempted without a notable positive effect.

Recent research indicates that the mitigation measures most cost-effective are those that lead moose away from high conflict areas and into areas with fewer conflicts.

The situation now exists in Romerike to develop new resource management models, relevant on a national level. The background knowledge on the Romerike moose population’s habitat use, the digitized map built over the resources available for the entire population, and the mitigation measures employed to reduce moose collisions provide a foundation for follow-up studies set in a na-tional perspective.

Conclusions

The results from the Romerike Moose Project show that when the construction is finished it will be more important than ever that a well coordinated plan be developed for the remaining natural areas in the greater Rome-rike area. It is also important that mitigation measures in the form of wildlife fences and fauna passages established along the airport travel routes be placed such that they promote moose access to desired natural areas.

Especially important for the health of the moose population is that access to the abundant winter range on the east side of E6 be improved over today’s level.

A landscape ecological perspective must be prioritized in the future plans for the remaining natural areas of Romerike. Vegetat-ion corridors of appropriate size must be pre-served between feeding areas so that moose and other animal species can safely travel among the remaining forested areas. Without these mitigating measures the food resources available to moose will be unacceptably reduced in the core winter habitat area. This will result in generally reduced health for the moose population and increase the movements related to feeding thereby increasing the num-ber of moose-vehicle collisions.