The GLOBIO3 model has been developed to assess human-induced changes in biodiversity, in the past, present, and future at regional and global scales. The model is built on simple cause-effect relationships between environmental drivers and biodiversity impacts, based on state-of-the-art knowledge. The mean abundance of original species relative to their abundance in undisturbed ecosystems (MSA) is used as the indicator for biodiversity. Changes in drivers are derived from the IMAGE 2.4 model. Drivers considered are landcover change, land-use intensity, fragmentation, climate change, atmospheric nitrogen deposition, and infrastructure development. GLOBIO3 addresses (i) the impacts of environmental drivers on MSA and their relative importance; (ii) expected trends under various future scenarios; and (iii) the likely effects of various policy response options. GLOBIO3 has been used successfully in several integrated regional and global assessments. Three different global-scale policy options have been evaluated on their potential to reduce MSA loss. These options are: climate-change mitigation through expanded use of bio-energy, an increase in plantation forestry, and an increase in protected areas. We conclude that MSA loss is likely to continue during the coming decades. Plantation forestry may help to reduce the rate of loss, whereas climate-change mitigation through the extensive use of bioenergy crops will, in fact, increase this rate of loss. The protection of 20% of all large ecosystems leads to a small reduction in the rate of loss, provided that protection is effective and that currently degraded protected areas are restored.

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Changes in vegetation cover in northern Chobe National Park (Botswana) were assessed using aerial photographs from1962,1985 and1998, with subsequent ground proofing. In addition, cumulative browsing by elephants and the occurrence of ¢re scars were recorded on random vegetation sites within shrubland (n 20) and mixed woodland (n 20). Coverage of woodland vegetation decreased from 60% to 30% between 1962 and 1998, while shrubland vegetation increased from 5% to 33% during the same period. During the study period, woodland has gradually retreated away from the river front. While riparian forest covered a continuous area along the riverfront in 1962, only fragments were left in 1998. We found a signi¢cant decrease in browse use with increasing distance to the Chobe river for Combretum apiculatum, Combretum elaeagnoides, Combretum mossambicense and other woody plants combined (all P < 0.0001). The occurrence of ¢re (P < 0.0001) and basal area (P < 0.0001) were positively related to distance to the river. Elephant browsing occurred on >70% of available stems within 2 km from the river, while less than 20% of the trees had ¢re scars in the same zone. Beyond 7 km from the river, elephant browsing was reduced to >50% of available stems, while more than 50% of the trees had ¢re scars. The density of any of the shrubs was not related to distance to the river neither within shrubland (all P > 0.05) nor within mixed woodlands (all P > 0.05).La densite¨d'aucunarbuste n'e¨tait lie¨e a© la distance jusqu'a© la rivie© re, ni dans la zone arbustive (ensemble P > 0.05) ni dans la zone arbore¨e me¨lange¨e (ensemble P > 0.05).

We studied reindeer (Rangifer tarandus tarandus) distribution in relation to possible travel barriers (roads and power lines) in south‐central Norway, 1997–2000, using lichen biomass as an indicator of reindeer use. We recorded lichen cover on both sides of potential barriers within comparable habitat in 42 sites for 3 different reindeer herds. We used cover–biomass regressions to assess the relationship between lichen cover and biomass. In 2 of the regions, lichen biomass was 5.3 times and 2.8 times higher in areas isolated by 2 parallel power lines and an adjacent winter‐closed road compared to biomass on the other side of the potential barrier. In a third region, lichen biomass did not vary significantly between areas on either side of a single winter‐closed road. Lichen biomass data suggested that wild reindeer used both sides of a closed road in winter, whereas 2 parallel power lines and a winter‐closed road in combination reduced reindeer migration and resulted in very different grazing pressures on either side of the power lines, even 30 years after the power lines were constructed. Construction of power lines, and particularly parallel power lines, should thus be avoided in wild reindeer habitat. Fragmentation of wild reindeer ranges in Norway results in a substantial reduction in available ranges and traditional migration routes between important seasonal ranges, with a likely overall reduction in carrying capacity.

ABSTRACT. Potential avoidance by wild reindeer (Rangifer tarandus tarandus) of high-altitude tourist resorts during winter was investigated in and near Rondane National Park in Norway. Distribution of reindeer was mapped using systematic snowmobile surveys during 1991-96 and compared with results from investigations of snow and vegetation characteristics. Maternal reindeer avoided a 10 km zone around the resort. Cows and calves increased in density from 0.6 ± 0.6 reindeer km -2 at 5-10 km from the resort to 7.6 ± 2.2 reindeer km -2 at 15-25 km from the resort. Bulls and yearlings were more tolerant, constituting nearly 92% of all observed animals 5-10 km from the resort. Nearly all animals avoided the zone within 5 km of the resort. There were no significant differences in distribution of lichen heath, hardness of snow, integrated ram hardness index (IRH) values, or snow depths on ridges with increasing distance from the resort. Available biomass of lichens was ca. 1200 g m -2 0-5 km from the resort and decreased to a low of ca. 250 g m -2 at 15-25 km distance, a pattern that probably reflects overgrazing as a result of avoiding the tourist resort. Such avoidance implies reduced forage intake during winter, substantial reduction in available habitat, and lower productivity of the herd. The results suggest that avoidance by wild animals of sources of anthropogenic disturbance may involve long-term impacts, such as reductions in carrying capacity, that are more serious than those expected from direct physiological stress.