焦山木本植物区系特征*

王从彦，刘君，肖鸿光

(江苏大学 环境生态研究所，环境与安全工程学院，江苏　镇江212013)



焦山木本植物区系特征*

王从彦，刘君，肖鸿光

(江苏大学 环境生态研究所，环境与安全工程学院，江苏镇江212013)

通过资源调查统计出镇江市焦山木本植物共97种，隶属于46科79属。46科分为13个分布类型，其中最多的三类为泛热带分布(26.09%)、北温带和南温带间断分布(17.39%)和北温带分布(6.52%)。79属分为19个分布类型，其中最多的三类为北温带分布(27.85%)、东亚和北美间断分布(10.13%)以及泛热带分布和东亚分布(8.86%)。故焦山木本植物具有一定的多样性。其区系在科水平具有明显的泛热带特征，但同时也具有较浓厚的温带成分。但在属水平表现出强烈的温带特征。同时，焦山木本植物区系与其周围山脉(特别是宝华山)木本植物区系具有较高的相关性和相似度。

木本植物；区系特征；过渡性；焦山

Flora is defined as the sum of all plant taxonomic units in one region within a certain period[1].Understanding the floral characteristics of plants in one region is necessary to elucidate the plants’natural environment and the main characteristics of plant resources[2].To date，some studies have been investigated on the floristic characteristics of seed plants in several mountains in Jiangsu Province，such as Mount Baohua(Zhenjiang)[3～4]，Mount Zijin(Nanjing)[5～6]，Mount Qixia(Nanjing)[7]，Mount Niushou(Nanjing)[8]，and Mount Lao(Nanjing)[9].Woody plants play an important role in the succession of plant communities in the mountainous areas.Unfortunately，very little is known about the floristic characteristics of woody plants in Mount Jiao，Zhenjiang.

This study aims to gain insights into the resources of woody plants in Mount Jiao，Zhenjiang，and provide a comprehensive depiction of their floristic characteristics via a thorough survey of these plants.Since Mount Jiao located in the northern part of the subtropical region，we hypothesize that the floristic characteristics of woody plants in Mount Jiao display strong transitional characteristics from pantropic to temperate.

1　Site description

As an island，Mount Jiao(Chinese name:焦山)is the only popular tourist spot that located in the middle of the Yangtze River.Jiaoshan(Mount Jiao)is also a district of Zhenjiang，southwest of Jiangsu Province.At present，Mount Jiao is a National AAAA-designated tourism area with a land area of approximately 100 hectares with average altitude of approximately 71m.Mount Jiao is famous for a large collection of more than four hundred ancient stone Chinese stele tablets，namely “Baomo Xuan”(Chinese name:宝墨轩)and/or “Jiaoshan Beilin”(Chinese name:焦山碑林).Mount Jiao is located in the transition zone between subtropical and warm temperate regions，and the area has a subtropical humid climate.The annual mean temperature of the area is approximately 15.6℃，and its monthly mean temperature reaches a maximum of 25℃ in July and decreases to a minimum of -1℃ in January.The annual precipitation is approximately 1 088mm，and the rainy season comes in June and July[10].

2　Method

In mid-April of 2015，woody plants in Mount Jiao were surveyed via a full-field investigation，and were analysed by using the method of floristic geography.In particular，the geographic elements of woody plants in Mount Jiao at family level were determined according to the standard floristic classification of world families of seed plants reported by Wu[11～12].The geographic elements of woody plants in Mount Jiao at the genus level were determined according to the standard of floristic classification on Chinese genera of seed plants reported by Wu[13～14].

The floristic characteristics of woody plants in Mount Jiao were characterized using the R/T value.The R/T of the geographic elements of woody plants in Mount Jiao was computed using the ratio of the tropic components(2～7)to the temperate components(8～14)according to previously described methods used by Wang[1].In general，a high R/T value indicates high tropical characteristics and a low R/T value indicates high temperate characteristics.

Species differentiation(SD)of woody plants in Mount Jiao calculated asSD=Ng/Nf+Ns/Ng[15]，whereNf，Ng，andNsare the sums of the numbers of families，genera，and species of all woody plants in Mount Jiao，respectively.In particular，highSDvalues signify greater differentiation and lowSDvalues indicate less differentiation.

The similarity of woody plants in Mount Jiao to those in circumferential mountains were characterized using the Sorenson similarity coefficient(SC)[1，16]:SC= [2C/(A+B)] × 100%，whereAandBare the sums of the numbers of families，genera，or species of all woody plants in two different mountains，a and b，respectively.Cis the sum of the numbers of families，genera，or species of all woody plants shared by both mountains(a and b).The Cosmopolitan element is not in the statistic range.In particular，highSCvalues indicate greater similarity in flora，whereas lowSCvalues denote less similarity in flora between the two mountains compared.

3　Results and discussion

3.1Plant composition at the family level

46 families of woody plants exist in Mount Jiao(Table 1).The following families of woody plants growing in Mount Jiao are arranged in descending order based on the number of members:Rosaceae(11 genera and 15 species);Oleaceae(5 genera and 6 species);Leguminosae(4 genera and 5 species);Cupressaceae(3 genera and 4 species);Pinaceae and Magnoliaceae(2 genera and 4 species);Hamamelidaceae，Caprifoliaceae，and Moraceae(3 genera and 3 species);Berberidaceae and Salicaceae(2 genera and 3 species);and Aceraceae(1 genera and 3 species).Furthermore，2 species of each of the following families exist in Mount Jiao:Taxodiaceae，Aquifoliaceae，Buxaceae，Apocynaceae，Celastraceae，Araliaceae，and Ulmaceae.Only one species of each of the following families grew in the area:Podocarpaceae，Cycadaceae，Ginkgoaceae，Alangiaceae，Euphorbiaceae，Ericaceae，Pittosporaceae，Saxifragaceae，Juglandaceae，Calycanthaceae，Meliaceae，Ranunculaceae，Anacardiaceae，Lythraceae，Rubiaceae，Solanaceae，Thymelaeaceae，Theaceae，Cornaceae，Punicaceae，Guttiferae，Sapindaceae，Sterculiaceae，Platanaceae，Myricaceae，Rutaceae，and Lauraceae(Table 1).In summary，12 families comprising three or more species(26.09%)，7 families including only 2 species(26.09%)，and 27 families comprising only one species(58.70%)are found in Mount Jiao(Table 1).The families that included only one species correspond to relatively isolated or ancient groups during phylogenetic development.Thus，despite belonging to a considerable number of families，woody plants in Mount Jiao mainly belong to depauperate or monotypic families.

Tab.1　Resources types and floristic characteristics of woody plants in Mount Jiao，Zhenjiang

Continued Table 1

Continued Table 1

LatinnameofplantspeciesClassifyFamilyFloraoffamilyGenusFloraofgenusGrowthformPunicagranatumLinn.Punicaceae12-4Punica12DeciduousshrubHypericummonogynumL.Guttiferae2Hypericum1EvergreenshrubEuonymusjaponicusThunb.var.aurea-marginatusHort.Celastraceae2Euonymus2EvergreenshrubEuonymusfortunei(Turcz.)Hand.-Mazz.EvergreenshrubFatsiajaponica(Thunb.)Decne.etPlanch.Araliaceae3Fatsia14EvergreenshrubHederanepalensisvar.sinensis(Tobl.)RehdHedera6EvergreenlianaKoelreuteriabipinnataFranch.var.integrifoliola(Merr.)T.ChenSapindaceae2Koelreuteria14DeciduoustreeFirmianaplatanifolia(Linn.f.)MarsiliSterculiaceae2Firmiana14(SH)DeciduoustreeMahoniabealei(Fort.)Carr.Berberidaceae8-5Mahonia9EvergreenshrubMahoniafortunei(Lindl.)FeddeEvergreenshrubNandinadomesticaThunb.Nandina14(SJ)EvergreenshrubPlatanusorientalisLinn.Platanaceae8Platanus8DeciduoustreeSalixbabylonicaLinn.Salicaceae8-4Salix8DeciduoustreeSalix×aureo-pendulaCL.DeciduoustreePopulus×canadensisMoenchPopulus8DeciduoustreeMyricarubra(Lour.)S.etZucc.Myricaceae1Myrica8-4EvergreentreeCeltissinensisPers.Ulmaceae1Celtis2DeciduoustreeUlmusparvifoliaJacq.Ulmus8DeciduoustreeCitrusreticulataBlancoRutaceae2Citrus7EvergreentreeCinnamomumamphora(L.)Presl.Lauraceae2Cinnamomum5Evergreentree

Note:1.Cosmopolitan;2.Pantropic;2-1.Trop.Asia，Australasia(to N.Zeal.)& C.to S.Amer.(or Mexico)disjuncted;2S.Pantropic especially S.Hemisphere;3.Trop.Asia & Amer.disjuncted;4.Old World Tropics;5.Trop.Asia & Trop.Oceania;6.Trop.Asia & Trop.Africa;6d.S.Afr.，chiefly Cape;7.Trop.Asia(Indo-Malesia);8 N.Temp.;8-4.N.Temp.& S.Temp.disjuncted;8-5.Eurasia & Temp.S.Amer.disjuncted;9.E.Asia & N.Amer.disjuncted;10.Old World Temp.;10-1.Mediterranea.W.Asia(or C.Asia)& E.Asia disjuncted;10-2.Mediterranea & Himalaya disjuncted;11.Temp.Asia;12.Medit.，W.& C.Asia;12-4.Mediterranea to Trop.Africa & Himalaya disjuncted;14.E.Asia;14(SH).Sino-Himalaya;14(SJ).Sino-Japan;15.Endemic to China.

3.2Geographic elements at the family level

According to the standard floristic classification of world families of seed plants proposed by Wu[11～12]，46 families of woody plants in Mount Jiao are classified into 13 areal types at the family level(Table 1).In particular，“Pantropic” comprises 12 families(26.09%)，“N.Temp.& S.Temp.disjuncted” includes 8 families(17.39%)，and “N.Temp.” comprises three3 families(6.52%).The 3 areal types，namely，“Trop.Asia & Amer.Disjuncted”，“Old World Tropics”，and “E.Asia & N.Amer.Disjuncted,” involve 2 families，accounting for 4.35% of the plants observed.The 7 areal types，namely，“Cosmopolitan”，“Pantropic especially S.Hemisphere”，“Trop.Asia & Trop.Oceania”，“S.Afr.，chiefly Cape”，“Eurasia & Temp.S.Amer.Disjuncted”，“Mediterranea to Trop.Africa & Himalaya disjuncted”，and “Endemic to China”，include only one family，accounting for 2.17% of the species found(Table 1).The aforementioned findings indicate that woody plants in Mount Jiao show a certain degree of diversity at the family level.Furthermore，a large proportion of plants may be classified under pantropic as well as temperate groups.The R/T of the geographic elements of woody plants in Mount Jiao at the family level is 1.2(Table 2).Thus，the floristic characteristics of woody plants in Mount Jiao at the family level exhibit a strong pantropic pattern but with abundant temperate characteristics because of the mountain’s location in the transition region between subtropical and warm temperate zones.This observation is consistent with our hypothesis.

3.3Plant composition at the genus level

79 genera of woody plants exist in Mount Jiao(Table 1).Pinus，Magnolia，andAcercomprise the largest number of plants(three species)in Mount Jiao at the genus level，totaling 3.80%.12 depauperate genera including two species(15.19%)and 64 monotypic genera comprising one species(81.01%)are also observed(Table 1).Thus，a number of genera of woody plants thrive in Mount Jiao，but these genera are dominated by depauperate or monotypic types.

3.4Geographic elements at the genus level

According to the standard floristic classification of Chinese genera of seed plants proposed by Wu[13～14]，79 genera of woody plants in Mount Jiao may be classified into 19 areal types at the genus level(Table 1).In particular，“N.Temp.” includes 22 genera(27.85%)，“E.Asia & N.Amer.Disjuncted” comprises 8 genera(10.13%)，both “Pantropic” and “E.Asia” include 7 genera(8.86%)，and “Trop.Asia(Indo-Malesia)” involves 5 genera(6.33%).The 4 areal types，namely，“Old World Tropics”，“Trop.Asia & Trop.Oceania”，“Mediterranea.W.Asia(or C.Asia)& E.Asia disjuncted”，and “Sino-Japan”，comprised 4 genera(5.06%).“Endemic to China” include 3 genera(3.80%).Both “N.Temp.& S.Temp.disjuncted” and “Old World Temp.” include 2 genera(2.53%).The 7 areal types，namely “Cosmopolitan”，“Trop.Asia，Australasia(to N.Zeal.)& C.to S.Amer.(or Mexico)disjuncted”，“Trop.Asia & Trop.Africa”，“Mediterranea & Himalaya disjuncted”，“Temp.Asia”，“Medit.，W.& C.Asia”，and “Sino-Himalaya”，consist of only one genus(1.27%)(Table 1).A large proportion of the plants exhibit temperate and pantropic distributions.The R/T of the geographic elements of woody plants in Mount Jiao at genus level is 0.42(Table 2).Thus，the floristic pattern of woody plants in Mount Jiao at the genus level display strong temperate characteristics because of Mount Jiao’s location north of the subtropical region.This result is inconsistent with our hypothesis.Based on this finding，the floristic characteristics of woody plants in Mount Jiao exhibit strong transition characteristics from pantropic to temperate at the family level but not at the genus level.In addition，woody plants in Mount Jiao include some genera that are classified under the areal type “Endemic to China,” which are generally monotypic and ancient groups.Thus，the floristic characteristics of woody plants in Mount Jiao at the genus level imply a certain degree of primitiveness.

3.5Plant composition at the species level

97 species of woody plants grow in Mount Jiao and belong to 46 families and 79 genera(Table 1).Among these species，13 are gymnosperms(13.40%)，classified under 6 families and 10 genera，and 85 are angiosperms(87.63%)，classified under 40 families and 89 genera.45 species of evergreen plants(46.39%)and 52 species of deciduous plants(53.61%)exist in the area.54 species of trees(55.67%)，41 species of shrub(42.27%)，and 3 species of liana(3.09%)also thrive in Mount Jiao(Table 1).Thus，woody plants in Mount Jiao exist mainly as deciduous trees.These data reveal obvious traces of a temperate pattern in the floristic characteristics of woody plants in Mount Jiao.In particular，the floristic characteristics of woody plants in Mount Jiao at the species level show an apparent pattern of transition from subtropical to warm temperate.This observation may be ascribed to Mount Jiao’s location north of the subtropical region.

3.6Comparison of the floristic characteristics of woody plants in Mount Jiao with those circumferential mountains

In this study，we compared the floristic characteristics of woody plants in Mount Jiao with those in circumferential mountains(i.e.，Mounts Zijin and Baohua)[3，5]to understand their correlations and similarities better.Results showed that woody plant resources in Mount Jiao were significantly fewer than those in Mounts Zijin and Baohua(Table 2).This result may be attributed to the significantly smaller area of Mount Jiao in comparison with the two other mountains;thus，the diversity of Mount Jiao’s ecological environment is less extensive than those of Mounts Zijin and Baohua.Confinement of the environment within Mount Jiao，which is also known as an island，may also explain the results obtained.By contrast，many foreign species may have been introduced to Mounts Baohua and Zijin，especially the latter.TheSDvalues of the three mountains increase with increasing area.The high degree of floristic differentiation of woody plants in mountains with large areas may be attributed to their multivariate environments.

The R/T values of the geographic elements of woody plants in the three mountains at the family level are consistently greater than 1(Table 2).Thus，the floristic characteristics of woody plants in the three mountains at the family level exhibit a strong pantropic pattern.However，the R/T values of the geographic elements of woody plants in the three mountains at the genus level are less than 1(Table 2).Thus，the floristic characteristics of woody plants in the three mountains at the genus level display strong temperate patterns because of the three mountains’location north of the subtropical region.Overall，the floristic characteristics of woody plants in the three mountains display strong transitional characteristics from pantropic to temperate because of their location in the transition zone between subtropical and warm temperate regions.

The similarity coefficients between Mounts Jiao and Baohua are apparently higher than those between Mounts Jiao and Zijin at the family，genus，and species levels(Table 2).This finding suggests that the floristic characteristics of woody plants in Mount Jiao exhibit strong correlations and similarities with those of Mount Baohua.This similarity may be attributed to their close locations and similar ecological environments.

Tab.2　Comparison of the floristic characteristics of woody plants in Mount Jiao with those in circumferential mountains

Note:The digits in the brackets represent the number of families，genera，or species of all woody plants shared by both mountains.

4　Conclusion

97 species of woody plants exist in Mount Jiao.These species belong to 46 families and 79 genera.The result reveal a certain degree of diversity among the woody plants in Mount Jiao.The floristic characteristics of woody plants in Mount Jiao at the family level exhibit strong pantropic but abundant temperate characteristics because of the mountain’s location at the transition zone between subtropical and warm temperate regions.The floristic characteristics of woody plants in Mount Jiao at the genus level display a strong temperate pattern because of Mount Jiao’s location north of the subtropical region.Meanwhile，the floristic characteristics of woody plants in Mount Jiao at the genus level imply a certain degree of primitiveness.Strong correlations and similarity with the woody plants in circumferential mountains，especially Mount Baohua，were also observed.

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Floristic Characteristics of Woody Plants in Mount Jiao

WANG Cong-yan，LIU Jun，XIAO Hong-guang

(Institute of Environment and Ecology，School of the Environment and Safety Engineering，Jiangsu University，Zhenjiang Jiangsu 212013，P.R.China)

This study aims to gain insights into the floristic characteristics of woody plants in Mount Jiao via a thorough survey.The flora includes 46 families，79 genera，and 97 species.46 families were classified into 13 areal types at the family level，among which “Pantropic”(26.09%)，“N.Temp.& S.Temp.disjuncted”(17.39%)，and “N.Temp.”(6.52%)are the 3 main types.79 genera were classified into 19 areal types at the genus level and 3 main types of “N.Temp.”(27.85%)，“E.Asia & N.Amer.Disjuncted”(10.13%)，and both “Pantropic” and “E.Asia”(8.86%).These results reveal a certain degree of diversity among the woody plants in Mount Jiao.The floristic characteristics of woody plants in Mount Jiao at the family level exhibit strong pantropic but abundant temperate characteristics.The reason might be the mountain’s location at the transition zone between subtropical and warm temperate regions.The floristic characteristics of woody plants in Mount Jiao at the genus level display a strong temperate pattern.There is significiant correlations and similarity with the woody plants in circumferential mountains，especially Mount Baohua.

woody plants;floristic characteristics;transition;Mount Jiao

10.16473/j.cnki.xblykx1972.2016.03.006

2015-07-28

国家自然科学基金(31300343)，江苏省自然科学基金(BK20130500)，江苏省高校自然科学研究项目(13KJB610002)，

王从彦 (1982-)，男，博士，副教授，主要从事环境生态学方面的研究。E-mail:liuyuexue623@163.com

Q 948

A

1672-8246(2016)03-0030-08

江苏大学高级专业人才科研启动基金(12JDG086)。