Dolan Rebecca W, Aronson Myla F J, Hipp Andrew L
Friesner Herbarium and Center for Urban Ecology, Butler University, Indianapolis, Indiana 46208.
Department of Ecology, Evolution and Natural Resources, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901.
Am J Bot. 2017 Aug;104(8):1179-1187. doi: 10.3732/ajb.1700136.
Globally, urban plant populations are becoming increasingly important, as these plants play a vital role in ameliorating effects of ecosystem disturbance and climate change. Urban environments act as filters to bioregional flora, presenting survival challenges to spontaneous plants. Yet, because of the paucity of inventory data on plants in landscapes both before and after urbanization, few studies have directly investigated this effect of urbanization.
We used historical, contemporary, and regional plant species inventories for Indianapolis, Indiana USA to evaluate how urbanization filters the bioregional flora based on species diversity, functional traits, and phylogenetic community structure.
Approximately 60% of the current regional flora was represented in the Indianapolis flora, both historically and presently. Native species that survived over time were significantly different in growth form, life form, and dispersal and pollination modes than those that were extirpated. Phylogenetically, the historical flora represented a random sample of the regional flora, while the current urban flora represented a nonrandom sample. Both graminoid habit and abiotic pollination are significantly more phylogenetically conserved than expected.
Our results likely reflect the shift from agricultural cover to built environment, coupled with the influence of human preference, in shaping the current urban flora of Indianapolis. Based on our analyses, the urban environment of Indianapolis does filter the bioregional species pool. To the extent that these filters are shared by other cities and operate similarly, we may see increasingly homogenized urban floras across regions, with concurrent loss of evolutionary information.
在全球范围内，城市植物种群正变得越来越重要，因为这些植物在缓解生态系统干扰和气候变化的影响方面发挥着至关重要的作用。城市环境对生物区域植物群起到筛选作用，给自生植物带来生存挑战。然而，由于缺乏城市化前后景观中植物的清查数据，很少有研究直接调查城市化的这种影响。
我们利用美国印第安纳州印第安纳波利斯市的历史、当代和区域植物物种清单，基于物种多样性、功能性状和系统发育群落结构来评估城市化如何筛选生物区域植物群。
无论是历史上还是现在，印第安纳波利斯市的植物群中约有60%代表了当前的区域植物群。随着时间推移存活下来的本地物种在生长形式、生活形式以及传播和授粉方式上与灭绝的物种有显著差异。从系统发育角度来看，历史植物群代表了区域植物群的随机样本，而当前的城市植物群代表了非随机样本。禾本科植物习性和非生物授粉在系统发育上的保守性都明显高于预期。
我们的结果可能反映了从农业用地向建筑环境的转变，以及人类偏好的影响，共同塑造了印第安纳波利斯市当前的城市植物群。基于我们的分析，印第安纳波利斯市的城市环境确实对生物区域物种库起到了筛选作用。如果其他城市也有类似的筛选作用且运作方式相同，我们可能会看到各地区城市植物群越来越趋同，同时进化信息也会随之丧失。
