北京城市鸟类夜栖时对本土和外来植物的利用

doi:10.17520/biods.2022399

摘要/Abstract

摘要：

随着城市化进程的加剧, 城市鸟类愈加依赖园林植物提供的栖息环境。与此同时, 外来植物在城市园林建设中的比例逐渐增加, 成为城市鸟类栖息地的重要组成部分。园林植物是城市鸟类的主要夜栖场所, 其合理配置可以为鸟类提供适宜的夜栖环境, 并维持城市鸟类多样性。研究城市鸟类对夜栖植物的利用, 可以为城市园林建设提供参考依据。2021-2022年, 我们通过红外热成像仪观察北京城市鸟类夜栖行为, 并对夜栖植物的种类、胸径、树高、冠幅和鸟类的栖枝高度进行测量与记录。共记录夜栖鸟类12科23种1,865只次, 夜栖植物22科45种。调查地的本土植物数量占45.08%, 外来植物数量占54.92%。夜栖于外来植物的鸟类数量约为本土植物的4倍。夜栖鸟类数量最多的植物为圆柏(Juniperus chinensis), 之后依次为美国红梣(Fraxinus pennsylvanica)、早园竹(Phyllostachys propinqua)、一球悬铃木(Platanus occidentalis)、旱柳(Salix matsudana)等。夜栖鸟类稀有度加权丰富度(rarity-weighted richness, RWR)最高的植物为圆柏, 之后依次为美国红梣、早园竹、油松(Pinus tabuliformis)、榆树(Ulmus pumila)等。本土夜栖植物的胸径、树高、冠幅和夜栖鸟类的栖枝高度显著高于外来植物。鸟类在冬季夜栖时对外来植物的利用比例(95.44%)显著高于其他季节(75.37%)。本研究结果表明, 北京城市园林建设中的外来植物丰富了鸟类的夜栖环境。

关键词: 外来植物, 城市鸟类, 夜栖植物, 季节差异, 北京

Abstract

Aims: With continually increasing urbanization, urban birds are becoming more reliant on the habitat provided by garden plants. At the same time, the proportion of alien plants in urban gardens have gradually increased, becoming an important part of urban bird habitats. Garden plants are the primary roosting site for urban birds, and their reasonable configuration can provide a suitable night roosting environment for birds and maintain urban bird diversity. Studying the use of night roosting plants by urban birds can provide a reference to conservationists for the construction of urban gardens.

Methods: From 2021 to 2022, infrared thermography was used to observe night-roosting bird behavior in Beijing. The species, diameter at breast height, tree height, canopy of night roosting plants, and perch height of birds were measured and recorded.

Results & Conclusions: A total of 1,865 recordings consisting of 23 species of birds in 12 families and 45 species of roosting plants in 22 families were documented. The number of native plants and alien plants in the study area accounted for 45.08% and 54.92%, respectively. The number of birds that roost in alien plants at night was about four times that of native plants. The plant with the largest number of night-roosting birds was Juniperus chinensis, followed by Fraxinus pennsylvanica, Phyllostachys propinqua, Platanus occidentalis, and Salix matsudana. The highest rarity-weighted richness of night-roosting birds was Juniperus chinensis, followed by Fraxinus pennsylvanica, Phyllostachys propinqua, Pinus tabuliformis, and Ulmus pumila. The diameter at breast height, tree height, canopy and perch height of night-roosting birds of native plants were significantly higher than those of alien plants. Birds utilized a significantly higher percentage of alien plants whilst roosting in winter (95.44%) than in other seasons (75.37%). Our findings suggest that alien plants enriched the night roosting environment of birds in Beijing urban gardens.

Key words: alien plants, urban birds, night roosting plants, seasonal variation, Beijing

赵也茜, 张家语, 李子涵, 解秦米佳, 邓歆, 王楠 (2023) 北京城市鸟类夜栖时对本土和外来植物的利用. 生物多样性, 31, 22399. DOI: 10.17520/biods.2022399.

Yexi Zhao, Jiayu Zhang, Zihan Li, Qinmijia Xie, Xin Deng, Nan Wang (2023) Use of native and alien plants during night roosting by urban birds in Beijing. Biodiversity Science, 31, 22399. DOI: 10.17520/biods.2022399.

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链接本文: https://www.biodiversity-science.net/CN/10.17520/biods.2022399

https://www.biodiversity-science.net/CN/Y2023/V31/I3/22399

图/表 6

图1 北京林业大学(A)及奥林匹克森林公园(B)夜栖植物分布图

Fig. 1 Distribution of night roosting plants in Beijing Forestry University (A) and Olympic Forest Park (B)

图2 夜栖鸟类与夜栖植物的关系。左侧鸟类名后的数字表示记录到此夜栖鸟类的个体数量, 右侧植物名前的数字表示夜栖于该种植物的鸟类个体数量。线条的宽度表示鸟类数量, 鸟类个体数量越多, 线条越宽。

Fig. 2 The relationship between night-roosting birds and plants. The number after the name of the bird on the left indicates the number of individuals recorded to this night-roosting bird. The number before the name of the plant on the right indicates the number of individual birds nocturnally inhabiting the plant. The width of the line indicates the number of birds, and the wider the line, the greater the number of birds.

图3 夜栖鸟类利用植物种数。1: 灰喜鹊; 2: 麻雀; 3: 喜鹊; 4: 珠颈斑鸠; 5: 乌鸫; 6: 白头鹎; 7: 黑尾蜡嘴雀; 8: 山斑鸠; 9: 燕雀; 10: 北灰鹟; 11: 赤颈鸫; 12: 红喉姬鹟; 13: 红尾斑鸫; 14: 红胸姬鹟; 15: 虎斑地鸫; 16: 灰背鸫; 17: 灰椋鸟; 18: 家燕; 19: 煤山雀; 20: 乌鹟; 21: 沼泽山雀; 22: 棕头鸦雀; 23: 纵纹腹小鸮。

Fig. 3 Number of plant species used by night-roosting birds. 1, Cyanopica cyanus; 2, Passer montanus; 3, Pica pica; 4, Streptopelia chinensis; 5, Turdus mandarinus; 6, Pycnonotus sinensis; 7, Eophona migratoria; 8, Streptopelia orientalis; 9, Fringilla montifringilla; 10, Muscicapa dauurica; 11, Turdus ruficollis; 12, Ficedula albicilla; 13, Turdus naumanni; 14, Ficedula parva; 15, Zoothera aurea; 16, Turdus hortulorum; 17, Spodiopsar cineraceus; 18, Hirundo rustica; 19, Periparus ater; 20, Muscicapa sibirica; 21, Poecile palustris; 22, Sinosuthora webbiana; 23, Athene noctua.

表1 本土和外来夜栖植物的比较(Kruskal-Wallis检验) (平均值 ± 标准误)

Table 1 Comparison of native and alien night roosting plants (Kruskal-Wallis test) (mean ± SE)

	本土植物 Native plants	外来植物 Alien plants	χ²	P
胸径 Diameter at breast height (cm)	39.28 ± 0.78	33.80 ± 0.52	71.115	< 0.01
树高 Tree height (m)	14.65 ± 0.15	12.84 ± 0.11	147.18	< 0.01
冠幅 Canopy (m)	10.44 ± 0.16	8.03 ± 0.11	167.71	< 0.01
栖枝高度 Perch height (m)	10.41 ± 0.15	8.46 ± 0.08	147.18	< 0.01

图4 各季节夜栖鸟类对本土和外来植物的利用比例

Fig. 4 Proportion of native and alien plants used by night-roosting birds in each season

图5 各季节夜栖植物的胸径(A)、树高(B)、冠幅(C)和栖枝高度(D)

Fig. 5 Diameter at breast height (A), tree height (B), canopy (C) and perch height (D) of night roosting plants in different season

参考文献 68

[1]	Albuquerque F, Astudillo-Scalia Y, Loyola R, Beier P (2019) Towards an understanding of the drivers of broad-scale patterns of rarity-weighted richness for vertebrates. Biodiversity and Conservation, 28, 3733-3747. DOI
[2]	Amo L, Caro SP, Visser ME (2011) Sleeping birds do not respond to predator odour. PLoS ONE, 6, e27576.
[3]	Aronson MF, Lepczyk CA, Evans KL, Goddard MA, Lerman SB, MacIvor JS, Nilon CH, Vargo T (2017) Biodiversity in the city: Key challenges for urban green space management. Frontiers in Ecology and the Environment, 15, 189-196. DOI URL
[4]	Bao MX, Yang S, Yang Y, Zhou S, Li CL (2019) Tolerance distance of common birds to human disturbances in urban areas. Journal of Biology, 36, 55-59. (in Chinese with English abstract)
	[鲍明霞, 杨森, 杨阳, 周盛, 李春林 (2019) 城市常见鸟类对人为干扰的耐受距离研究. 生物学杂志, 36, 55-59.]
[5]	Bates D, Mächler M, Bolker B, Walker S (2015) Fitting linear mixed-effects models using lme4. Journal of Statistical Software, 67(1), 1-48.
[6]	Blair RB (1996) Land use and avian species diversity along an urban gradient. Ecological Applications, 6, 506-519. DOI URL
[7]	Bonnet-Lebrun AS, Manica A, Rodrigues ASL (2020) Effects of urbanization on bird migration. Biological Conservation, 244, 108423. DOI URL
[8]	Buttemer WA (1985) Energy relations of winter roost-site utilization by American goldfinches (Carduelis tristis). Oecologia, 68, 126-132. DOI PMID
[9]	Catling PM (2005) Effects of invasive alien plants on birds: Some examples from North America. Biodiversity, 6, 30-39. DOI URL
[10]	Chace JF, Walsh JJ (2006) Urban effects on native avifauna: A review. Landscape and Urban Planning, 74, 46-69. DOI URL
[11]	Clergeau P, Savard JPL, Mennechez G, Falardeau G (1998) Bird abundance and diversity along an urban-rural gradient: A comparative study between two cities on different continents. The Condor, 100, 413-425. DOI URL
[12]	Conklin JR, Colwell MA (2007) Diurnal and nocturnal roost site fidelity of dunlin (Calidris alpina pacifica) at Humboldt Bay, California. The Auk, 124, 677-689.
[13]	Davis AM, Glick TF (1978) Urban ecosystems and island biogeography. Environmental Conservation, 5, 299-304. DOI URL
[14]	Dearborn DC, Kark S (2010) Motivations for conserving urban biodiversity. Conservation Biology, 24, 432-440. DOI PMID
[15]	Dwyer JF, McPherson EG, Schroeder HW, Rowntree RA (1992) Assessing the benefits and costs of the urban forest. Arboriculture & Urban Forestry, 18, 227-234.
[16]	Fontana S, Sattler T, Bontadina F, Moretti M (2011) How to manage the urban green to improve bird diversity and community structure. Landscape and Urban Planning, 101, 278-285. DOI URL
[17]	Francis WJ (1976) Micrometeorology of a blackbird roost. Journal of Wildlife Management, 40, 132-136. DOI URL
[18]	Glazier DS (1986) Temporal variability of abundance and the distribution of species. Oikos, 47, 309-314. DOI URL
[19]	Grimm NB, Faeth SH, Golubiewski NE, Redman CL, Wu JG, Bai XM, Briggs JM (2008) Global change and the ecology of cities. Science, 319, 756-760. DOI PMID
[20]	Hao S, Luo W, Liang ZF, Yin YD (2021) Research on landscape design strategy of university campus based on bird habitat protection: Taking Peking University as an example. Architecture & Culture, (2), 136-137. (in Chinese with English abstract)
	[郝晟, 罗薇, 梁增飞, 殷颖迪 (2021) 基于鸟类栖息地保护的大学校园景观设计策略研究——以北京大学为例. 建筑与文化, (2), 136-137.]
[21]	He HY, Wang N, Dong L (2021) A case study to investigate the foraging pattern of urban birds on edible plants in Beijing. Chinese Journal of Zoology, 56, 491-499. (in Chinese with English abstract)
	[何海燕, 王楠, 董路 (2021) 北京城市鸟类对食源植物利用规律. 动物学杂志, 56, 491-499.]
[22]	He SY (1992) Flora of Beijing. I. Beijing Press, Beijing. (in Chinese)
	[贺士元 (1992) 北京植物志, 上册. 北京出版社, 北京.]
[23]	Hou DM, Hui H, Zhang DR, Xiao NW, Rao DQ (2023) Diversity of amphibians and reptiles in Yunnan region of the Yunling Mountains. Biodiversity Science, 31, 22316. (in Chinese with English abstract) DOI
	[侯东敏, 辉洪, 张栋儒, 肖能文, 饶定齐 (2023) 云岭山脉云南地区两栖爬行类动物多样性. 生物多样性, 31, 22316.] DOI
[24]	Hu J, Wu YX, Lü LS (2006) General introduction of Beijing Olympic Forest Park landscape plan. Chinese Landscape Architecture, 22(6), 1-7. (in Chinese with English abstract)
	[胡洁, 吴宜夏, 吕璐珊 (2006) 北京奥林匹克森林公园景观规划设计综述. 中国园林, 22(6), 1-7.]
[25]	Hu N, Wang YH, Li X (2018) Construction of campus green space from the perspective of green campus—Taking Beijing Forestry University as an example. Landscape Architecture, 25(3), 25-31. (in Chinese with English abstract)
	[胡楠, 王宇泓, 李雄 (2018) 绿色校园视角下的校园绿地建设——以北京林业大学为例. 风景园林, 25(3), 25-31.]
[26]	Jirinec V, Varian CP, Smith CJ, Leu M (2016) Mismatch between diurnal home ranges and roosting areas in the wood thrush (Hylocichla mustelina): Possible role of habitat and breeding stage. The Auk, 133, 1-12. DOI URL
[27]	Kemp DD (2004) Exploring Environmental Issues: An Integrated Approach. Routledge, London.
[28]	Lenth RV (2022) Emmeans: Estimated marginal means, aka least-squares means. R package version 1.8.2. https://CRAN.R-project.org/package=emmeans. (accessed on 2022-10-30).
[29]	Liang YQ, Li JW, Li J, Valimaki SK (2008) Impact of urbanization on plant diversity: A case study in built-up areas of Beijing. Forestry Studies in China, 10, 179-188. DOI URL
[30]	Millard A (2008) Semi-natural vegetation and its relationship to designated urban green space at the landscape scale in Leeds, UK. Landscape Ecology, 23, 1231-1241. DOI URL
[31]	Mitchell WF, Clarke RH (2019) Using infrared thermography to detect night-roosting birds. Journal of Field Ornithology, 90, 39-51. DOI
[32]	Moraes ALB, Da Silveira NS, Pizo MA (2018) Nocturnal roosting behavior of the pale-breasted thrush (Turdus leucomelas) and its relation with daytime area of use. The Wilson Journal of Ornithology, 130, 828-833.
[33]	Nilon CH, Aronson MFJ, Cilliers SS, Dobbs C, Frazee LJ, Goddard MA, O’Neill KM, Roberts D, Stander EK, Werner P, Winter M, Yocom KP (2017) Planning for the future of urban biodiversity: A global review of city-scale initiatives. BioScience, 67, 332-342. DOI URL
[34]	Pan Y, Gao JX, Zhou KX, An SQ, Yuan BD (2019) Night roosting habitat of oriental magpie robin (Copsychus saularis) during breeding and non-breeding stages in urban green land. Chinese Journal of Ecology, 38, 2772-2779. (in Chinese with English abstract)
	[潘扬, 高吉喜, 周可新, 安树青, 原宝东 (2019) 城市绿地中鹊鸲繁殖期和非繁殖期夜栖地选择. 生态学杂志, 38, 2772-2779.]
[35]	Peh KSH, Sodhi NS (2002) Characteristics of nocturnal roosts of house crows in Singapore. Journal of Wildlife Management, 66, 1128-1133. DOI URL
[36]	Pei NC, Wang C, Jin JL, Jia BQ, Chen BF, Qie GF, Qiu EF, Gu L, Sun RL, Li JR, Zhang C, Jiang SS, Zhang Z (2018) Long-term afforestation efforts increase bird species diversity in Beijing, China. Urban Forestry & Urban Greening, 29, 88-95.
[37]	Peng SL, Xiang YC (1999) The invasion of exotic plants and effects of ecosystems. Acta Ecologica Sinica, 19, 560-568. (in Chinese with English abstract)
	[彭少麟, 向言词 (1999) 植物外来种入侵及其对生态系统的影响. 生态学报, 19, 560-568.]
[38]	Potgieter LJ, Gaertner M, Kueffer C, Larson BMH, Livingstone SW, O’Farrell PJ, Richardson DM (2017) Alien plants as mediators of ecosystem services and disservices in urban systems: A global review. Biological Invasions, 19, 3571-3588. DOI URL
[39]	Pyšek P (1998) Alien and native species in Central European urban floras: A quantitative comparison. Journal of Biogeography, 25, 155-163. DOI URL
[40]	R Core Team (2021) R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria.
[41]	Savard JPL, Clergeau P, Mennechez G (2000) Biodiversity concepts and urban ecosystems. Landscape and Urban Planning, 48, 131-142. DOI URL
[42]	Shupova TV (2021) Connections of alien bird species with alien plants of parks and botanical gardens. Studia Biologica, 15, 79-92. DOI URL
[43]	Shwartz A, Turbé A, Simon L, Julliard R (2014) Enhancing urban biodiversity and its influence on city-dwellers: An experiment. Biological Conservation, 171, 82-90. DOI URL
[44]	Sulaiman S, Mohamad NHN, Idilfitri S (2013) Contribution of vegetation in urban parks as habitat for selective bird community. Procedia - Social and Behavioral Sciences, 85, 267-281. DOI URL
[45]	Sun QH, Zhang ZW, Zhu JG, Gao ZJ (2002) Roosting behavior and factors affecting roost-site used by Reeve’s pheasant (Syrmaticus reevesii) in winter. Journal of Beijing Normal University (Natural Science), 38(1), 108-112. (in Chinese with English abstract)
	[孙全辉, 张正旺, 朱家贵, 高振建 (2002) 白冠长尾雉冬季夜栖行为与夜栖地利用影响因子的研究. 北京师范大学学报(自然科学版), 38(1), 108-112.]
[46]	Szlavecz K, Warren P, Pickett S (2011) Biodiversity on the urban landscape. In: Human Population (eds Cincotta RP, Gorenflo LJ), pp. 75-101. Springer, Berlin, Heidelberg.
[47]	Thiel D, Unger C, Kéry M, Jenni L (2007) Selection of night roosts in winter by capercaillie Tetrao urogallus in central Europe. Wildlife Biology, 13, 73-86. DOI URL
[48]	Thompson FR, Fritzell EK (1988) Ruffed grouse winter roost site preference and influence on energy demands. Journal of Wildlife Management, 52, 454-460. DOI URL
[49]	Threlfall CG, Williams NSG, Hahs AK, Livesley SJ (2016) Approaches to urban vegetation management and the impacts on urban bird and bat assemblages. Landscape and Urban Planning, 153, 28-39. DOI URL
[50]	Walsberg GE (1986) Thermal consequences of roost-site selection: The relative importance of three modes of heat conservation. The Auk, 103, 1-7.
[51]	Wang GM, Jiang GM, Zhou YL, Liu QR, Ji YS, Wang SX, Chen SB, Liu H (2007) Biodiversity conservation in a fast-growing metropolitan area in China: A case study of plant diversity in Beijing. Biodiversity and Conservation, 16, 4025-4038. DOI URL
[52]	Wang HF, MacGregor-Fors I, López-Pujol J (2012) Warm-temperate, immense, and sprawling: Plant diversity drivers in urban Beijing, China. Plant Ecology, 213, 967-992. DOI URL
[53]	Wang XP, Li DZ, Sheng LJ, Zhu ZL, Ke SZ, Wang CH (2007) Significance of birds, bees and butterflies in urban gardens and their attraction and protection. Scientia Silvae Sinicae, 43(12), 134-143. (in Chinese with English abstract)
	[王绪平, 李德志, 盛丽娟, 朱志玲, 柯世朕, 王超华 (2007) 城市园林中鸟类及蜂蝶的重要性及其招引与保护. 林业科学, 43(12), 134-143.]
[54]	Watts BD, Smith FM, Hines C, Duval L, Hamilton DJ, Keyes T, Paquet J, Pirie-Dominix L, Rausch J, Truitt B, Winn B, Woodard P (2021) The costs of using night roosts for migrating whimbrels. Journal of Avian Biology, 52(1), e02629.
[55]	Webb DA (1985) What are the criteria for presuming native status? Watsonia, 15, 231-236.
[56]	Webb WB (1974) Sleep as an adaptive response. Perceptual and Motor Skills, 38, 1023-1027. PMID
[57]	Whitford V, Ennos AR, Handley JF (2001) “City form and natural process”—Indicators for the ecological performance of urban areas and their application to Merseyside, UK. Landscape and Urban Planning, 57, 91-103. DOI URL
[58]	Williams NSG, Schwartz MW, Vesk PA, McCarthy MA, Hahs AK, Clemants SE, Corlett RT, Duncan RP, Norton BA, Thompson K, McDonnell MJ (2009) A conceptual framework for predicting the effects of urban environments on floras. Journal of Ecology, 97, 4-9. DOI URL
[59]	Williams P, Gibbons D, Margules C, Rebelo A, Humphries C, Pressey R (1996) A comparison of richness hotspots, rarity hotspots, and complementary areas for conserving diversity of British birds. Conservation Biology, 10, 155-174. DOI URL
[60]	Yang G, Wang Y, Xu J, Ding YZ, Wu SY, Tang HM, Li HQ, Wang XM, Ma B, Wang ZH (2015) The influence of habitat types on bird community in urban parks. Acta Ecologica Sinica, 35, 4186-4195. (in Chinese with English abstract)
	[杨刚, 王勇, 许洁, 丁由中, 吴时英, 唐海明, 李宏庆, 王小明, 马波, 王正寰 (2015) 城市公园生境类型对鸟类群落的影响. 生态学报, 35, 4186-4195.]
[61]	Yu QY, Mi CR, Xing SH, Li H (2012) Analysis of plant species composition in Beijing Olympic Forest Park. Ecological Science, 31, 646-651. (in Chinese with English abstract)
	[余琦殷, 宓春荣, 邢韶华, 李晖 (2012) 北京市奥林匹克森林公园植物组成分析. 生态科学, 31, 646-651.]
[62]	Yuan BD, Jiang AW, Li XD, Lu CH (2012) Roost habitat selection by birds: A review. Chinese Journal of Ecology, 31, 2145-2151. (in Chinese with English abstract)
	[原宝东, 蒋爱伍, 李晓东, 鲁长虎 (2012) 鸟类夜栖地选择研究进展. 生态学杂志, 31, 2145-2151.]
[63]	Zhang SP, Zheng GM, Xu JL (2006) Habitat use of urban tree sparrows in the process of urbanization: Beijing as a case study. Biodiversity Science, 14, 372-381. (in Chinese with English abstract) DOI
	[张淑萍, 郑光美, 徐基良 (2006) 城市化对城市麻雀栖息地利用的影响: 以北京市为例. 生物多样性, 14, 372-381.] DOI
[64]	Zhang WQ, Dong L (2015) Study of bird preference to plant habitat and species in Beijing urban park. Chinese Landscape Architecture, 31(8), 15-19. (in Chinese with English abstract)
	[张皖清, 董丽 (2015) 北京城市公园中鸟类对植物生境及种类的偏好研究. 中国园林, 31(8), 15-19.]
[65]	Zhang ZK, Huang GL (2018) Urban ornithological research in China: A review. Acta Ecologica Sinica, 38, 3357-3367. (in Chinese with English abstract)
	[张征恺, 黄甘霖 (2018) 中国城市鸟类学研究进展. 生态学报, 38, 3357-3367.]
[66]	Zhao JJ, Ouyang ZY, Xu WH, Zheng H, Meng XS (2010) Sampling adequacy estimation for plant species composition by accumulation curves—A case study of urban vegetation in Beijing, China. Landscape and Urban Planning, 95, 113-121. DOI URL
[67]	Zhao JJ, Ouyang ZY, Zheng H, Xu WH, Wang XK (2009) Species composition and spatial structure of plants in urban parks of Beijing. Chinese Journal of Applied Ecology, 20, 298-306. (in Chinese with English abstract)
	[赵娟娟, 欧阳志云, 郑华, 徐卫华, 王效科 (2009) 北京城区公园的植物种类构成及空间结构. 应用生态学报, 20, 298-306.]
[68]	Zheng BJ, Dong L (2019) Study on plant landscape of Beijing urban linear parks based on bird diversity improvement. Landscape Architecture, 26(1), 53-57. (in Chinese with English abstract)
	[郑冰晶, 董丽 (2019) 基于提高鸟类多样性的北京城市线性公园绿地植物景观探析. 风景园林, 26(1), 53-57.]