{"title":"Grassland vegetation in urban habitats – testing ecological theories","authors":"B. Deák, Bernadett Hüse, B. Tóthmérész","doi":"10.14471/2016.36.017","DOIUrl":null,"url":null,"abstract":"During the last millennium, urbanization has considerably changed natural ecosystems and formed new artificial habitats. Habitat loss and changes in the abiotic environment are seriously affecting urban biodiversity. We investigated the vegetation composition of three urban habitat types, vacant lots, urban parks, and peri-urban grasslands, which are characterised by species typical to semi-natural grasslands and ruderal assemblages in the city of Debrecen (East-Hungary). We used five spatial replicates of each habitat type and five random plots (5 m × 5 m) in every site for our analyses. We tested the following hypotheses: (1) lower species numbers and Shannon diversity, and a higher proportion of weeds and disturbance-tolerant species are present in the city centre (i.e. urban parks) compared to more peripheral habitats (vacant lots and peri-urban grasslands), (2) the proportion of warmand nitrogen-demanding species increases, while the proportion of moisture-demanding species decreases in habitats typical to city centres (3) we also tested the increase in cosmopolitan and alien species and the decrease in species of the natural flora in habitats typical to city centres as predicted by the urban homogenisation hypothesis. We found that species composition of urban habitat types is considerably affected by the specific disturbances and site histories associated with the certain habitats. The most urbanised habitats, the urban parks harboured the lowest number of species and the lowest Shannon diversity. The ratio of weeds and disturbance-tolerants was the highest in the city centre likely due to the high-intensity trampling and soil disturbances. Plant species of city centre were more drought-tolerant compared to periurban grasslands, which is likely due to the increased level of drainage. The ratio of nitrogendemanding species was lower in urban parks and peri-urban grasslands than in vacant lots, likely due to the high level of recent soil disturbance in this habitat type. The proportion of alien species was high both in vacant lots and peri-urban grasslands, even though their disturbance regimes differed considerably. The proportion of cosmopolitan species was significantly higher in urban parks compared to vacant lots and peri-urban grasslands. The large proportion of alien and cosmopolitan species together with the continuous human disturbance put native species at a competitive disadvantage, and accordingly the proportion of these species was lowest in the city centre. Even though the studied urban habitat patches did not contribute considerably to the preservation of rare or endangered plant species, they have an essential role in preserving the last remnants of grasslands in intensively used landscapes, and can be a good basis for urban greening projects. Manuscript received 18 January 2016, accepted 07 May 2016 Co-ordinating Editor: Laura Sutcliffe 380","PeriodicalId":48870,"journal":{"name":"Tuexenia","volume":"36 1","pages":"379-393"},"PeriodicalIF":1.1000,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"31","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Tuexenia","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.14471/2016.36.017","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PLANT SCIENCES","Score":null,"Total":0}
引用次数: 31
Abstract
During the last millennium, urbanization has considerably changed natural ecosystems and formed new artificial habitats. Habitat loss and changes in the abiotic environment are seriously affecting urban biodiversity. We investigated the vegetation composition of three urban habitat types, vacant lots, urban parks, and peri-urban grasslands, which are characterised by species typical to semi-natural grasslands and ruderal assemblages in the city of Debrecen (East-Hungary). We used five spatial replicates of each habitat type and five random plots (5 m × 5 m) in every site for our analyses. We tested the following hypotheses: (1) lower species numbers and Shannon diversity, and a higher proportion of weeds and disturbance-tolerant species are present in the city centre (i.e. urban parks) compared to more peripheral habitats (vacant lots and peri-urban grasslands), (2) the proportion of warmand nitrogen-demanding species increases, while the proportion of moisture-demanding species decreases in habitats typical to city centres (3) we also tested the increase in cosmopolitan and alien species and the decrease in species of the natural flora in habitats typical to city centres as predicted by the urban homogenisation hypothesis. We found that species composition of urban habitat types is considerably affected by the specific disturbances and site histories associated with the certain habitats. The most urbanised habitats, the urban parks harboured the lowest number of species and the lowest Shannon diversity. The ratio of weeds and disturbance-tolerants was the highest in the city centre likely due to the high-intensity trampling and soil disturbances. Plant species of city centre were more drought-tolerant compared to periurban grasslands, which is likely due to the increased level of drainage. The ratio of nitrogendemanding species was lower in urban parks and peri-urban grasslands than in vacant lots, likely due to the high level of recent soil disturbance in this habitat type. The proportion of alien species was high both in vacant lots and peri-urban grasslands, even though their disturbance regimes differed considerably. The proportion of cosmopolitan species was significantly higher in urban parks compared to vacant lots and peri-urban grasslands. The large proportion of alien and cosmopolitan species together with the continuous human disturbance put native species at a competitive disadvantage, and accordingly the proportion of these species was lowest in the city centre. Even though the studied urban habitat patches did not contribute considerably to the preservation of rare or endangered plant species, they have an essential role in preserving the last remnants of grasslands in intensively used landscapes, and can be a good basis for urban greening projects. Manuscript received 18 January 2016, accepted 07 May 2016 Co-ordinating Editor: Laura Sutcliffe 380
在过去的一千年里,城市化极大地改变了自然生态系统,形成了新的人工栖息地。生境丧失和非生物环境变化严重影响着城市生物多样性。研究了德布勒森(匈牙利东部)3种城市生境类型的植被组成,即空地、城市公园和城郊草原,它们的特征是典型的半自然草原和原始草原。我们在每个站点使用5个空间重复和5个随机样地(5 m × 5 m)进行分析。我们测试了以下假设:(1)与周边生境(空地和城郊草原)相比,城市中心(即城市公园)的物种数量和Shannon多样性较低,杂草和耐干扰物种的比例较高;(2)需要温暖和氮的物种比例增加;虽然在城市中心的典型生境中,需要水分的物种的比例减少(3),但我们也测试了城市中心的典型生境中,世界性和外来物种的增加以及自然植物群的减少,这是由城市均质化假说预测的。研究发现,城市生境类型的物种组成受到与特定生境相关的特定干扰和立地历史的显著影响。作为城市化程度最高的栖息地,城市公园拥有最少的物种数量和最低的香农多样性。杂草和耐扰植物的比例在市中心最高,可能是由于高强度的踩踏和土壤干扰。与城郊草原相比,城市中心的植物物种更耐旱,这可能是由于排水水平的提高。城市公园和城郊草原的需氮物种比例低于空地,这可能是由于该生境类型近期土壤扰动程度高所致。在空地和城郊草原,外来物种的比例都很高,尽管它们的干扰程度不同。城市公园的世界性物种比例显著高于空地和城郊草原。外来物种和世界性物种所占的比例较大,加之持续的人为干扰,使本地物种处于竞争劣势,因此这些物种在市中心的比例最低。尽管所研究的城市生境斑块对保护稀有或濒危植物物种的贡献不大,但它们在保护集约利用景观中最后残余的草地方面具有重要作用,可以作为城市绿化工程的良好基础。2016年1月18日收稿,2016年5月7日收稿
期刊介绍:
Tuexenia publiziert Original- und Übersichtsarbeiten sowie Berichte zu Themen der Geobotanik / Vegetationsökologie und zu Nachbarwissenschaften wie Populationsökologie, Biodiversitätsforschung, Biozönologie, Renaturierungsökologie und ihren Anwendungen, vor allem im Naturschutz. Der geografische Schwerpunkt liegt in Zentraleuropa und angrenzenden Regionen.Tuexenia erscheint jährlich in einem Band, der etwa zur Jahresmitte fertig gestellt wird. Autoren erhalten von jeder Arbeit eine PDF-Datei und gemeinsam 20 Sonderdrucke kostenlos.
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