Please enable JavaScript.

Coggle requires JavaScript to display documents.

U.r.b.a.n. P.l.a.n.t.s. (Distribution (Urban hard surfaces (wall type…

- - - - naturalised vs invasive
      - numbers of native & neophytes increase more steeply with city size
- - - - highest: forest; lowest: desert
- - - - incre prop of edge habitats
        
        abrupt, linear and adjacent to built-environment
        
        poor dispersers, produce few seeds, depend on mutualism, inbreeding depression
    - - incre soil nutrients
        
        exotics/generalists need more N
        
        native specialists decline with enrichment
        
        vigourous herbaceous spp outcompete tree seedlings
      - decre soil water
        
        diversity incre with moisture
      - incre temp
        
        UHI advance flowering time, reduce gene flow
        
        frost suppresses/removes spp. originate from warmer areas
    - - landuse
        
        inputs: fert, water
        
        wetlands/grasslands/urban green spaces
    - - -ve: air,soil polltn, mechanical, invasives; +ve: natural fires, flooding, windfall
      - intermediate disturbance hypothesis
      - restricted photosynthesis
      - life-strategies
        
        competitive
        
        water channels
        
        ruderal
        
        domestic gardens
        
        stress-tolerant
        
        roadsides + high salt
    - - forest cover incre with per cap income in US
        
        ppl plant more of their own with rising income, less public trees
      - +ve r/s canopy cover and income
      - public trees as source of medicine and nutrition in slums: Bangalore
      - legacy effect: inherited from past events
    - - can lack >1 strata
        
        shrubs removed or heavy use
        
        emergent
    - - fragmentation
      - impervious surface
      - scarce animal pollinators and seed dispersers
      - avail of other indiv, pollinators, seed-dispersers, substrates for growth
      - low density of plants
      - alternate food sources
      - benefits?
        
        enhanced by urban airflows
        
        vehicles, pedestrians
        
        frugivores visit urban
        
        migratory birds may stop in urban green spaces
    - - accelerate leaf litter decomp, loss of OM, loss of C & P, disrupt soil food webs
      - shift from fungi to bacteria dominated cycling
    - - site properties, human impacts, species responses
      - cities as major centers for spread of exotics
  - - - site condition (wet/intermediate/dry)
      - veg origin (spontaneous/planted)
      - predominant process (human maintenance/disturbance OR ecological succession)
  - - - high connectivity btwn cities and countryside
      - many Mediterranean spp tolerate arid conditions
    - - incre urban cover, decre natives, increa exotics
      - no effect on total spp richness
      - prop decre in natives matched by incre in exotics
    - - tree density decre with urbanisation
      - tree diversity incre w urbanisation
      - lower income in periurban than urban
- - - - lawns
      - plants on built elements
      - forest
  - - - plants on built elements
      - forest
      - lawns
- - - - Dutch Elm Disease from 3 elm bark beetles
    - - emerald ash borer
    - - Santamour’s 10‐20‐30 rule
        
        Actual mean relative abundances
        in 108 cities: 20 %, 26 %, 32 %
  - - - resilience to disease
      - intro pest & disease
    - - incre with propagule pressure & residence time
  - - - low cover for mowing
      - fruiting shrubs for frugivores. more fruits than trees
  - - - may not be functionally diverse
    - - better adapted
      - failing native gardens
  - - - mowing strongly selects for tolerant spp
      - chemical use
      - noise, air pollution, carbon footprint
  - - - mainly limited by moisture
      - cyano: more drought & stress tolerant
      - wall base with dog pee
    - - most stress‐ & drought‐tolerant spp
        are usually crustose cf. foliose & fruticose
      - in SG conc.: Zn > Cu > Pb > Ni > As > Cd
      - cover: veh pollution; sp richness: moisture, colonisation sources
        
        plant more trees
      - UHI intensity also affects
    - - mostly on walls
      - moisture-limited, esp gametophytes
    - - often first colonisers
    - - drought tolerant: succulent habit, leaf hairs, in‐rolled leaves
      - annuals dominate in India
    - - dry stone walls: greater aeration, less water
      - mortared walls: softer, less alkaline
        
        weathering, temp change, fracturing, trap OM, pH decre
        
        soil behind wall
      - mud & brick walls
      - moisture
        
        most abundant & diverse wall veg in humid oceanic climates (high rainfall, stable Tº)
        
        slope of wall
      - zonation
        
        horizontal ledge
        
        allow substrate to accumulate and support more plants, but block rainfall onto surfaces below
        
        wall top
        
        often have greater diversity & abundance. more accessible to animal dispersers, more substrate e.g. poo
        
        upper level
        
        often has more plant cover
        
        more trees on taller walls - less disturbance, shelter from wind etc.
        
        base
        
        wettest, horizontal, accumulates debris and nutrients, leading to soil development and decre pH, but high disturbance
        
        disturbance hinderance to germination
        
        middle level
        
        most exposed, may retain more nutrients closer to base and favour nutrient‐loving spp
    - - trampling‐tolerant species
      - halophytes: coastal areas, and inland salting areas
    - - species spread vegetatively, most by propagules
      - Walls may receive more but retain fewer propagules than
        pavement
        
        plant types
        
        stress‐tolerant rock specialists
        
        early‐successional generalists
        
        problems
        
        species on hard surfaces tend to be tenacious
        
        Mechanisms that increase substrate for plants also degrade walls
        
        Woody plants can increase risk of fire
        
        Biofilms produced by cyanobacteria and others can enhance accumulation of atmospheric pollutants
        
        Vegetation on river walls can hinder access
        
        Weight of vegetation can make walls unstable
      - River walls often dominated by species that disperse in water
      - Vertical surfaces mainly colonised by wind‐dispersed species, wall tops mainly by animal‐dispersed species
      - pavements: trampling fragments, seeds on tires
        
        problems
        
        Roots cause buckling or cracking - reduce value
        
        In oceanic climates, mosses can be a nuisance/complaints
        
        Most ecological studies are tests of weed control methods!
        
        obscures surfaces