Biosphere conservation : for nature, wildlife, and humans
Online ISSN : 2433-1260
Print ISSN : 1344-6797
1 巻 , 2 号
選択された号の論文の9件中1~9を表示しています
Reviews & Essays
  • Asir Jawahar Thomas Johnsingh, Ravi Chellam, Diwakar Sharma
    原稿種別: Reviews & Essays
    1998 年 1 巻 2 号 p. 81-89
    発行日: 1998年
    公開日: 2017/10/03
    ジャーナル フリー
    The only remaining population of Asiatic lions (Panthera leo persica), numbering about 300 individuals, is now confined to 1, 883 km2 of the Gir forest in the state of Gujarat, western India. Numerous problems such as temples, biotic pressures exerted by the maldharis, a pastoral tribe, and the villages on the periphery, and quarrying for limestone continue to throttle the prospects for long-term survival of the Gir forest and its lions. Long-term conservation of lions can be ensured by intensively managing Gir as a better habitat for ungulates and lions, and by establishing a second free-ranging population in the Kuno Wildlife Sanctuary in Central India, already identified as a possible reintroduction site. The quality of wild ungulate habitat in Gir can be improved by thinning of teak (Tectona grandis) forests, a tree species not palatable to ungulates, allowing local people to harvest mature grass as an ecodevelopment measure, and by shifting maldhari nesses to create blocks of disturbance-free habitats. The forest patches around Gir should be managed as effectively as possible in accordance with the Greater Gir Ecosystem Concept, to suit the requirements of the lion. However, whenever conflicts with people occur, the animals involved should be removed immediately. Efforts should be made to strengthen the Gir Welfare Fund, which is used for the benefit of the staff, by promoting and receiving revenue from ecotourism and accepting donations from foreign zoos by gifting the problem lions which are captured outside Gir. The conservation community needs to be united in its views to save the lion, and a second home for the lion should be established as planned. Public support for protecting Gir and its lions can be harnessed by enlightening people about the economic contribution of Gir to the region's economy, the ecological and cultural suitability of the lion for promoting a sustainable tourist trade, and the spiritual benefits provided by this charismatic predator.
  • Thomas R. Loughlin
    原稿種別: Reviews & Essays
    1998 年 1 巻 2 号 p. 91-98
    発行日: 1998年
    公開日: 2017/10/03
    ジャーナル フリー
    Steller sea lions (Eumetopias jubatus) are the largest of the sea lion and fur seal subfamily and show a marked difference in size with males two to three times larger than females. Males can be as large as 1,120 kg and grow to 3.25 m; they are about the size of a Kodiak grizzly bear (Ursus arctos). Females average 250 kg and are approximately 3.2 m long. The Steller sea lion breeding range extends across the North Pacific Ocean rim, from the Kuril Islands and Okhotsk Sea, through the Aleutian Islands and Bering Sea, along Alaska's southern coast, and south to central California. Steller sea lions eat a variety of fishes and invertebrates. In Alaska, the principal prey is walleye pollock (Theragra chalcogramma) with Pacific cod (Gadus macrocephalus), Atka mackerel (Pleurogrammus monopterygius), octopus, squid, herring (Clupea harengus), flatfishes, and sculpins also consumed. There were reportedly over 300,000 Steller sea lions in the world in the late 1970s. Since then, the Alaskan sea lion population has plummeted to a small fraction of earlier levels resulting in the species being listed as threatened under the U.S. Endangered Species Act (ESA) in November 1990; the western stock was changed to endangered in 1997. Possible causes for the decline may include redistribution, changed vital rates, pollution, predation, subsistence use, commercial harvest, disease, natural fluctuation, environmental changes, and commercial fishing. The last two are now considered the most probable links to the decline. Steller sea lions may be affected by commercial fishing directly through incidental catch in nets, by entanglement in derelict debris, by shooting, or indirectly through competition for prey, disturbance, or disruption of prey schools. Current research is trying to determine the relationship between commercial fisheries and the decline and to monitor status. Management regimes include restrictions on incidental take, prohibition of shooting sea lions, no trawl buffer zones around some rookeries, and other measures.
Original Papers
  • Javier Castroviejo
    原稿種別: Original Papers
    1998 年 1 巻 2 号 p. 99-106
    発行日: 1998年
    公開日: 2017/10/03
    ジャーナル フリー
    A century ago the wolf occupied almost the whole of Spain except for a narrow strip along the Mediterranean coast from southern Andalusia to the French border. This shrinking process began fifty years ago and continued for decades. The first fragmentation of the distribution area took place between 1930 and 1940, when the wolves of the Pyrenees were isolated from the main population of western Spain. The latter broke up around 1950 into two distinct populations: a) a large northern population located north of the Tajo river, diminishing north of the Duero river, and b) a small southern population restricted to the mountains of Sierra Morena, Montes de Toledo and Extremadura. The northern population has been spreading since 1980 and its current numbers are between 1,500 and 2,000 individuals which occupy a continuous area of 100,000km2. Most wolves occur in densely populated areas and feed on domestic animals, carrion and rubbish. On the other hand, the remnants of the southern population are composed of two isolated groups of 10-15 wolves each. They survive in well-preserved Mediterranean forests (Quercus ilex, Q. suber, Cistus sp., etc.) in the Sierra de S. Pedro (Caceres) and in central Sierra Morena at the junction of Cordoba, Jaen and Ciudad Real provinces. In this area, the human population density is very low and the wolves rely on wild prey (Cervus elaphus, Capreolus capreolus, Sus scrofa, etc.). Paradoxically, the Spanish northern population, which is the largest and probably the healthiest of western Europe, thrives in highly adverse ecological conditions. On the contrary, Sierra Morena and Sierra de S. Pedro in southern Spain support small and highly endangered wolf populations which barely survive in apparently excellent natural conditions. However, the intensive use of fences for big game management makes wolf survival difficult.
  • John W. Bickham, Thomas R. Loughlin, Jeffrey K. Wickliffe, Vladimir N. ...
    原稿種別: Original Papers
    1998 年 1 巻 2 号 p. 107-117
    発行日: 1998年
    公開日: 2017/10/03
    ジャーナル フリー
    Nucleotide sequence analysis of a 238 base-pair segment of the mitochondrial control region for 392 Steller sea lions (Eumetopias jubatus) from rookeries across nearly the entire distributional range of the species supports the hypothesis of two genetically differentiated stocks. An eastern stock includes rookeries in California, Oregon, British Columbia, and southeastern Alaska. A western stock includes rookeries in Prince William Sound, the Bering Sea, Central Gulf of Alaska, Western Gulf of Alaska, Eastern Aleutian Islands, Central Aleutian Islands, Russia (Commander Islands and Kamchatka), and the Kuril Islands. The distribution of haplotypes and a phylogenetic analysis of the haplotypes provides evidence for the reconstruction of the evolutionary history of the populations. Steller sea lions diverged genetically as the result of being isolated in at least two, and possibly three, glacial refugia. The data indicate that females have a relatively high level of philopatry and the control region has a rapid rate of evolution, which has resulted in relatively high levels of haplotype endemism in some areas. In particular, the Kuril Islands appear to be highly variable with many low-frequency haplotypes unique to that area.
  • Taku Maeda
    原稿種別: Original Papers
    1998 年 1 巻 2 号 p. 119-128
    発行日: 1998年
    公開日: 2017/10/03
    ジャーナル フリー
    In a suburb of Tokyo in the winter of 1991/1992 and in the summer of 1992, uses of vegetation by birds were surveyed at seven sites within broad-leaved deciduous coppices and the effects of undergrowth removal on birds were examined. More than 80% of bird species were observed in the upper layer (>2 m high) of every site. With a few exceptions, the number of bird species was smaller in the lower layer (<2 m high) than in the upper layer, and smallest at sites without undergrowth. Well-grown undergrowth was attractive to several bird species such as blackfaced buntings (Emberiza spodocephala) and red-flanked bluetails (Tarsiger cyanurus) in winter, and Siberian meadow buntings (E. cioides) in summer. The preferennce of some bird species for specific layers was dependent on the amount of vegetation. The exposed ground in forests without undergrowth was frequently used by a few species of birds such as feral pigeons (Columba livia), tree sparrows (Passer montanus) and grey starlings (Sturnus cineraceus), all of which adapted to unforested urban habitat. Thus, it could be concluded that undergrowth removal negatively affects bird species diversity in suburban coppices.
  • Huapeng Chen, Feng Li, Zhongwu Sun, Jianzhang Ma, Huai Wang, Liyang Lu ...
    原稿種別: Original Papers
    1998 年 1 巻 2 号 p. 129-140
    発行日: 1998年
    公開日: 2017/10/03
    ジャーナル フリー
    Seasonal selection of forages by red deer (Cervus elaphus) and roe deer (Capreolus capreolus) was studied in relation to availability and chemical composition in coniferous-deciduous forests of northeastern China from 1991 to 1992. Forage availability varied significantly among seasons. It was greatest in summer (168.4 and 160.3 g dry matter/m2 for red deer and roe deer, respectively) and smallest in winter (22.9 and 22.4 g dry matter/m2 in clearcuts, and 21.3 and 16.5 g dry matter/m2 in matured forests for red deer and roe deer, respectively). Red deer selected forbs in summer and autumn (p < 0.05), and avoided sedges in summer, browses in spring and autumn, and ferns in summer and autumn (p < 0.05), whereas roe deer selected forbs during snow-free seasons, and avoided sedges in summer and autumn, browses in spring, and ferns during snow-free seasons (p < 0.05). In winter, red deer selected Pinus koraiensis, and avoided Tilia mandshurica (p < 0.05), whereas roe deer selected Salix spp. and Pinus koraiensis, and avoided Corylus mandshurica and Syringa amurensis (p < 0.05). Relationships between the electivity indices (EI) and chemical composition (CP, NDF, ADF, IVDMD and minerals) were explored for red deer and roe deer, using simple, multiple and stepwise regressions. Correlation between the EI and chemical composition varied among seasons and no consistent relationships were found for red deer or roe deer. Roe deer appeared to be more selective than red deer during snow-free seasons, and showed lower preference to ligneous browse plants than red deer. Consequently, roe deer ate more nutritious foods during snow-free seasons, but ate less nutritious foods during winter than red deer.
  • Yoko Goto, Kenji Shimazaki
    原稿種別: Original Papers
    1998 年 1 巻 2 号 p. 141-148
    発行日: 1998年
    公開日: 2017/10/03
    ジャーナル フリー
    Stomachs were examined from 67 Steller sea lions (Eumetopias jubatus) killed by hunters off the coast of Rausu in the Nemuro Strait, Hokkaido, from January to March, 1994-1996, to determine feeding habits. Five stomachs were empty. Prey species were identified by using the hard parts of fishes and cephalopods (e. g., fish bones, otoliths and cephalopod beaks). The most common prey was walleye pollock (Theragra chalcogramma). Other frequently occurring prey species were Pacific cod (Gadus macrocephalus), saffron cod (Eleginus gracilis), cephalopods, and flatfishes (Pleuronectidae). The percent weight of each of these species differed by year and month. These differences may be related to catch by commercial fisheries, as the consumption of walleye pollock decreased during years when few were caught by commercial fishermen. Length of fish prey was estimated using a formula derived from the relationship between otolith or subopercle size and fish length. Lower rostrum length of squid beaks was used to estimate mantle length by deriving a similar formula. Estimated body length of gadids ranged from 5 to 100 cm, and mantle length of squids ranged from 5 to 25 cm. There was no significant relationship between sea lion body length and estimated prey size.
  • Takeomi Isono
    原稿種別: Original Papers
    1998 年 1 巻 2 号 p. 149-160
    発行日: 1998年
    公開日: 2017/10/03
    ジャーナル フリー
    To clarify the development of the external morphology, skull and canines of Steller sea lions (Eumetopias jubatus), 79 animals were captured off the coast of Rausu, Rebun Island and Shakotan Peninsula, northern Japan, during January to March between 1994 and 1996. From the measurements of 30 parts of the external morphology, 26 parts of the skull and 9 parts of the canine, changes with age, and relative growth were analyzed. Increases in standard length, condylobasal length and canine length tended to level off at about 5 years in females, while in males, growth of these parts continued for at least 10 years. Comparison of the relative changes in numerous body measurements with increasing standard length indicated that development of the upper half of the body is remarkable in males. Females show remarkable foreflipper growth. Using condylobasal length as the base of measurement, skull width indicated positive allometry in males. In females, these measurements indicated negative allometry, and only the length of the snout showed positive allometry. Relative growth of the external morphology and skull differed in both sexes, but relative growth of the canines was similar. Only canine root length showed positive allometry. Male canines were significantly wider than the female canines. The males had thicker canines, wider skulls and bigger upper bodies than the females. These traits are considered advantageous for males maintaining territories during the breeding season.
  • Satoshi Ohdachi
    原稿種別: Original Papers
    1998 年 1 巻 2 号 p. 161-163
    発行日: 1998年
    公開日: 2017/10/03
    ジャーナル フリー
    One shrew specimen which is identified as Sorex unguiculatus in Abe et al. (1997) was reexamined. According to morphological characters and nucleotide sequences of the mitochondrial cytochrome b gene, it is reidentified as Sorex isodon.
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