Spatial distribution and size of small canopy gaps created by Japanese black bears: estimating gap size using dropped branch measurements

Annals of Occupational and Environmental Medicine

Kazuaki Takahashi²  Kaori Takahashi¹ 

[1] Division of Gene Research, Department of Life Science, Research Center for Human and Environmental Sciences, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan

[2] Faculty of Tourism and Environmental Studies, Nagano University, 658-1 Shimonogo, Ueda, Nagano 386-1298, Japan

关键词: Topography;    Gap height;    Gap formation;    Gap distribution;    Canopy disturbance;    Bear shelf;    Animal–plant interaction;   

Others  :  1085332
DOI  :  10.1186/1472-6785-13-23

 received in 2013-01-08, accepted in 2013-05-22,  发布年份 2013

【 摘 要 】

Background

Japanese black bears, a large-bodied omnivore, frequently create small gaps in the tree crown during fruit foraging. However, there are no previous reports of black bear-created canopy gaps. To characterize physical canopy disturbance by black bears, we examined a number of parameters, including the species of trees in which canopy gaps were created, gap size, the horizontal and vertical distribution of gaps, and the size of branches broken to create gaps. The size of black bear-created canopy gaps was estimated using data from branches that had been broken and dropped on the ground.

Results

The disturbance regime was characterized by a highly biased distribution of small canopy gaps on ridges, a large total overall gap area, a wide range in gap height relative to canopy height, and diversity in gap size. Surprisingly, the annual rate of bear-created canopy gap formation reached 141.3 m² ha^–1 yr^–1 on ridges, which were hot spots in terms of black bear activity. This rate was approximately 6.6 times that of tree-fall gap formation on ridges at this study site. Furthermore, this rate was approximately two to three times that of common tree-fall gap formation in Japanese forests, as reported in other studies.

Conclusions

Our findings suggest that the ecological interaction between black bears and fruit-bearing trees may create a unique light regime, distinct from that created by tree falls, which increases the availability of light resources to plants below the canopy.

【 授权许可】

   
2013 Takahashi and Takahashi; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Figure 7.

Figure 8.

Figure 9.

【 参考文献 】

• [1]Hubbell SP, Foster RB, O’Brien ST, Harms KE, Condit R, Wechsler B, Wright SJ, Loo de Lao S: Light-gap disturbances, recruitment limitation, and tree diversity in a neotropical forest. Science 1999, 283:554-557.
• [2]Denslow JS: Tropical rainforest gaps and tree species diversity. Annu Rev Ecol Evol Syst 1987, 18:431-451.
• [3]Canham CD, Denslow JS, Platt WJ, Runkle JR, Spies TA, White PS: Light regimes beneath closed canopies and tree-fall gaps in temperate and tropical forests. Can J Forest Res 1990, 2:620-631.
• [4]Nakashizuka T: Role of uprooting in composition and dynamics of an old-growth forest in Japan. Ecology 1989, 70:1273-1278.
• [5]Canham CD: Growth and canopy architecture of shade-tolerant trees: response to canopy gaps. Ecology 1988, 69:786-795.
• [6]Kohyama T: Size-structured tree populations in gap-dynamic forest–the forest architecture hypothesis for the stable coexistence of species. J Ecol 1993, 81:131-143.
• [7]Yamamoto S, Nishimura N: Canopy gap formation and replacement pattern of major tree species among developmental stages of beech (Fagus crenata) stands, Japan. Plant Ecol 1999, 140:167-176.
• [8]Brokaw N, Busing RT: Niche versus chance and tree diversity in forest gaps. Trends Ecol Evol 2000, 15:183-188.
• [9]Jones CG, Lawton JH, Shachak M: Organisms as ecosystem engineers. Oikos 1994, 69:373-386.
• [10]Schliemann SA, Bockheim JG: Methods for studying treefall gaps: A review. For Ecol Manage 2011, 261:1143-1151.
• [11]Zhang QH, Zak LC: Effects of gap size on litter decomposition and microbial activity in a subtropical forest. Ecology 1995, 76:2196-2204.
• [12]Muscolo A, Sidari M, Mercurio R: Influence of gap size on organic matter decomposition, microbial biomass and nutrient cycle in Calabrian pine (Pinus laricio, Poiret) stands. For Ecol Manage 2007, 242:412-418.
• [13]Denslow JS, Hartshorn GS: Tree-fall gap environments and forest dynamic processes. In La Selva: Ecology and Natural History of a Neotropical Rain Forest. Edited by McDade LA. Chicago (USA): University of Chicago Press; 2004:s129.
• [14]Runkle JR: Gap regeneration in some old-growth forests of the eastern United States. Ecology 1981, 62:1041-1051.
• [15]Green PT: Canopy gaps in rain forest on Christmas Island, Indian Ocean: size distribution and methods of measurement. J Trop Ecol 1996, 12:427-434.
• [16]Yamamoto K: Estimation of the canopy gap size using two photographs taken at different heights. Ecol Res 2000, 15:203-208.
• [17]Hu L, Zhu J: Determination of the tridimensional shape of canopy gaps using two hemispherical photographs. Agr Forest Meteorol 2009, 149:862-872.
• [18]Koike S, Kasai S, Yamazaki K, Furubayashi K: Fruit phenology of Prunus jamasakura and the feeding habit of Asiatic black bear as a seed disperser. Ecol Res 2008, 23:385-392.
• [19]Frazer GW, Canham CD, Lertzman KP: Gap Light Analyzer v2.0. New York (USA): Simon Fraser University, Burnaby, British Columbia, and the Institute of Ecosystem Studies, Millbrook; 1999.
• [20]Morisita M: easuring of interspecific association and similarity between communities. Memoirs Faculty of Science, Kyushu University. Series E. Biology 1959, 3:65-80.
• [21]StatSoft: STATISTICA for Windows Release 10.0. Oklahoma (USA): StatSoft, Tulsa; 2011.
• [22]Lima RAF, Moura LC: Gap disturbance regime and composition in the Atlantic Montane Rain Forest: the influence of topography. Plant Ecol 2008, 197:239-253.
• [23]Clinton BD, Boring LR, Swank WT: Canopy gap characteristics and drought influences in oak forests of the Coweeta Basin. Ecology 1993, 74:1551-1558.
• [24]Battles JJ, Fahey TJ, Harney EMB: Spatial patterning in the canopy gap regime of a subalpine Abies-Picea forest in the northeastern United States. J Veg Sci 1995, 6:807-814.
• [25]Gale N: The relationship between canopy gaps and topography in a western Ecuadorian rain forest. Biotropica 2000, 32:653-661.
• [26]Ward JS, Parker GR: Spatial dispersion of woody regeneration in an old-growth forest. Ecology 1989, 70:1279-1285.
• [27]Kubota Y: Spatial dynamics of regeneration in a conifer/broad-leaved forest in northern Japan. J Veg Sci 2000, 11:633-640.
• [28]Hashimoto Y, Takatsuki S: Food habits of Japanese black bears: a review. Mammalian Science 1997, 37:1-19. (in Japanese with English summary)
• [29]Abe S, Masaki T, Nakashizuka T: Factors influencing sapling composition in canopy gaps of a temperate deciduous forest. Plant Ecol 1995, 120:21-32.
• [30]Dahir SE, Lorimer CG: Variation in canopy gap formation among developmental stages of northern hardwood stands. Can J Forest Res 1996, 26:1875-1892.
• [31]Henbo Y, Itaya A, Nishimura N, Yamamoto S: Long-term canopy dynamics in a large area of temperate old-growth beech (Fagus crenata) forest: analysis by aerial photographs and digital elevation models. J Ecol 2004, 92:945-953.
• [32]Naaf T, Wulf M: Effects of gap size, light and herbivory on the herb layer vegetation in European beech forest gaps. For Ecol Manage 2007, 244:141-149.
• [33]Nakashizuka T, Iida S, Tanaka H, Shibata M, Abe S, Masaki T, Niiyama K: Community dynamics of Ogawa Forest Reserve, a species rich deciduous forest, central Japan. Plant Ecol 1992, 103:105-112.
• [34]Naka K: Community dynamics of evergreen broadleaf forests in southwestern Japan. I. Wind damaged trees and canopy gaps in an evergreen oak forest. J Plant Res 1982, 95:385-399.
• [35]Shibata M, Tanaka H, Iida S, Abe S, Masaki T, Niiyama K, Nakashizuka T: Synchronized annual seed production by 16 principal tree species in a temperate deciduous forest, Japan. Ecology 2002, 83:1727-1742.
• [36]Yasaka M, Terazaw K, Koyama H, Kon H: Masting behavior of Fagus crenata in northern Japan: spatial synchrony and pre-dispersal seed predation. For Ecol Manage 2003, 184:277-284.
• [37]Kishimoto R, Sato S: Outline and issues of population monitoring in the Asiatic black bear (Ursus thibetanus) management plans of Nagano Prefecture. Mammalian Science 2008, 48:73-81. (in Japanese with English summary)
• [38]Ministry of the Environment: Threatened Wildlife of Japan—Red Data Book, 2nd edition—Volume 1: Mammalia. Tokyo (Japan): Japan Wildlife Research Center; 2002. (in Japanese with English summary)