The passage author states that kivas are places she associates with: mystery and excitement. rest and healing from illness. worship and instruction. ACT.7 35 GO ON TO THE NEXT PAGE. Passage IV 55 Lundholm of St. Mary's University in Halifax, Nova Scotia, and his then student Ashley. Marlin, concluded that many successful urban plants are native to exposed cliffs. diStbed rock outcrops, or dry grnsslands, all of which are characterized by soils with a relatively high 60 pH. Cities. with their tall, granite-faced buildings and concrete foundations, are in a sense the equivalent of the natural limestone cliff habitats where those species originated. Similarly, as the British ecologist and "Ilchen hunter" Oliver L. Gilbert noted in his classic 65 book The Ecologi of Urban Habitats, the increased use of deicing salts on our rOS and highways has resulted in the development of microhabitats along their margins that are typically colonized by calcium-loving grass- land species adapted to lime.stone soils or by salt-loving 70 planis fro coastal babitais. In general. the successful urban plant needs to be flexible in au aspects of its life history, frorn seed ger- mination through flowering and fruiting" opportunistic in its ability to take advantage of locally abundant 75 resources that may be available for only a short time: and tolerant of the stressful growing conditions caused by an abundance of pavement and a paucity of soil. The plants that grow in our cities managed to survive the transition from one land use to another as cities dev¢l- 80 oped. The sequence starts with native species adapted to ecological conditions befoIe the city was built. Those are followed. more or less in order, by species preadapted to agriculture and pasturage. to pavement and compacted soil. to lawns and landscaping, to infra- &5 Structure edges and environmental pollution-and ulti- mately to vacant lots and rubble. NATURAL SCIENCE: This passage is adapted from Ihe article he Asphalt Jungle" by Peter Del Tr8dici (V2010 by Natural History Magazlne, Inc.). The ecology of the city is defined not Only by the cultivated plants that require 1nt¢llance and the pro- tected ren]nants of natural landscapes, but also by the spontaneous Yegetation that dominates the neglected 5 interstices. Greenery fills the vacant spaces between our roads, homes, and businesses: lines ditches and chain-link fetlces; sprouts in sidewalk cracks and atop neglected .rooftops. Some of those plants, such as box elder, quaking aspen, and riverside grape, are native 10 species present before humans drastically altered the land. Others, including chicory, Japanese knotweed. and Norway maple, were brought in intentionally or . unintentionally by people. And still others-amolls them common ragweed. path rush (Juneus lenuis), and 15 tufted lovegrass (Eragrostis pectlnacea)-T1Ved OD their owll, dispersed by willd, water, or wild aninmls. Such species grow and reproduce in man! American cities without. being planted or cared for. They can pro- vide important ecological services at very little cost to 20 taxpayers, and if left undisturbed IoDg enough they may. even develop into mature woodlands. There is no denying that most people consider many such plants to be "we¢ds." From a utilitarian per- 'spective. a weed is any plant that grows on its own 25 where people do not want it to grow. From the biologi- cal perspective, weeds are opporttulistic plants that are adapted to disturbance in all its myriad fornis, from bulldozers to acid rain. Their pervasiveness in the urban environment is simply a reflection of the continual dis- 30 rnption that characterizes that babitat-they are not its cause. In an agricultural context. tbe competition of weeds with economic crops is the primary reason for controlling them. In an urban area, a weed is any plant growing where people are trying to cultivate something 85 else, or keep clear of vegetation altogether. The com- plaints of city dwellers are usually based on aesthetics (the plants are perceived as ugly, or as signs of blight and neglect) or on security concerns (they shield human activity or provide habitat for v¢n]JiD). From a plant's perspective, it is not the density of the human population that d¢fines the urban environ- rnent, but the abundance of paving (affectino access to soil and moisture) and prevalence of disturbance. In other words, a sidewalk crack is a sidewalk crack 45 whether it is in a city or a suburb. Urballization is a process, not a place-a process. that tends to leave the soil in a compacted, impoverished. and often contami- nated state.
