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Distribution and population status

10.4 Status of the Asiatic black bear in Iwate

10.4.1 Distribution and population status

A study completed in 1989 estimated that there were approximately 1,000 bears in Iwate Prefecture. A further study, conducted between 2001 and 2002, estimated that there were about 1,100 bears in Iwate Prefecture, distributed predominantly in the northern Ōu mountains in the west, and Kitakami mountains in the east. From these studies, it has been suggested that the bear population is relatively stable.46 A document published by Iwate Prefecture in 2003 concluded from these studies that there was no risk of the bear’s extinction in Iwate Prefecture in the foreseeable future, because there is a ‘balance between annual birth rates and harvest rates’.47 However, at the same time, the report noted that there are fluctuations in annual birth rates (as there are in culling rates), and as population studies are conducted only infrequently, there is arguably a high degree of uncertainty about the bear’s population status and trends. It should also be noted that there is far from universal agreement concerning these population figures, which are, after all, only estimates: some observers believe that the population is much greater, while others are convinced it is lower.

According to recent research, there are two morphologically distinct bear populations in Iwate Prefecture. The study compared the skull morphology of the bears which inhabit the Ōu mountains to the west of the prefecture with those of the Kitakami Highlands towards the east of the prefecture, which are separated by the Kitakami River basin. The results indicated that the bears from these two areas have probably been isolated from each other for a considerable period of time, and that the gene flow between them is limited, despite the fact that the distance between the two ranges is only several kilometres at the nearest points.48 The distinct populations can be clearly seen in Figures 35 and 36.

Figure 34: ‘Nametoko Mountain’ today: the beech forest which once covered its slopes has been completely clear-cut. (Photo: Okuta, H.)

Studies conducted by the Prefecture have found that the area of overall bear activity (represented by the lighter shading [green] in Figures 35 and 36) has increased, particularly in the case of the Kitakami population. This expansion of overall activity, and particularly feeding activity, is thought to be caused by the deterioration and reduction of the bears’ natural habitat and the increase in crops such as corn and apples grown in upland, or forest-margin areas, which serve to attract bears onto or near farms.49 Other farming practices, such as the dumping of spoilt apples in fields or in the forest, are a significant factor in drawing bears into human inhabited areas. At the same time, the area in which breeding activity has been confirmed to take place (represented by the darker [red] shading in the figures) has decreased over the past decade. This can be attributed to the decrease in availability of suitable sites for denning, such as holes in or under large trees, which are at a safe distance from human noise and activity.

These simultaneous changes in the distribution of bear activity represent two distinct threats to the sustainability of the bear population in Iwate. On the one hand the increase in overall bear activity,

Figure 35: Distribution of bears in Iwate in 1989 . Darker (red) shading indicates areas where breeding activity occurs; lighter (green) shading indicates areas where bear ‘appearances’ occur. (Source: Iwate Prefecture, 2003)

Figure 36: Distribution in 2001. As can be seen, areas in which breeding activity has been confirmed has decreased markedly, while areas in which bear ‘appearances’ occur has increased. (Source: Iwate Prefecture, 2003)

which involves increased activity in human-inhabited areas, has the potential to lead to an increase in human-bear conflict, which, given the current policy, will inevitably lead to an increase in culling. On the other hand, the decrease in areas in which there are suitable sites for breeding and denning has the potential to lead to a decrease in the frequency and success of breeding, which will ultimately impact on the bear population in Iwate.

According to data collected over the period from 1990 to 2005, an average of approximately 140 bears are harvested (through hunting or culling activity) annually in Iwate. Of those, an average of approximately 57 per cent were harvested during the hunting period (15th November to 15th February), while the remaining 43 per cent were culled as ‘nuisance bears’ following incidents of pestilence, attacks or in some cases, simply sightings.

Obvious though it may seem, these figures do not include undeclared harvests or poaching, neither of which are likely to be uncommon, owing to the highly lucrative market for bear gall and the lack of monitoring and policing of hunting activity.50 Though there are no figures on poaching available, in the course of his research for the Iwate Nippō series on bears outlined later in the chapter, Azumane (1993) was shown one illegal trap in the Ōu mountains, and was informed by hunters that they do occasionally find such illegal traps on their hunting rounds.51

Figure 37: Harvests of Asiatic black bear in Iwate Prefecture (1978–2005)

As can be seen from Figure 37, while hunting harvests have generally been between 50 and 10 annually, culling figures have fluctuated considerably and are closely connected to the incidence of bear pestilence in a given year. Until the late 1990s, bears harvested through hunting generally outnumbered those harvested through culling. However, in the early 2000s, that pattern had been reversed, with culling numbers generally greater than hunting numbers.

Since 1999, in line with a stronger emphasis on conservation, the Prefecture has set a maximum annual harvest figure, the aim of which is to ensure that the overall population neither decreases nor increases by more than three per cent.52 For the year 2005, this was set at 110 (37 for the Kita-Ōu population, and 63 for the Kitakami population), and the actual harvest for the year was under this limit, at 94.53 While it is tempting to conclude from these figures that the actual harvest was a result of the strict adherence to the hunting/culling limit, the main factor in the limit not being exceeded is more likely to be the lower incidence of bear activity in human-inhabited areas in that year: in 2005 there was a comparatively good harvest of beech and oak nuts in the Iwate region. In 2006, by contrast, the cull totalled 219—almost double the limit—owing to the high rate of bear appearances and pestilence in 2006, itself thought to be a consequence of a poor mast.54