EVSC30006 Lecture Notes - Lecture 21: Coarse Woody Debris, Sydney Gardens, Keystone Species
1 Jun 2018
School
Department
Course
Professor
LECTURE 21: THE URBAN MATRIX
• Urban environments are landscape mosaics where habitat remnants are typically surrounded by heterogenous
urban matrix
o Can’t depend on remnants to maintain biodiversity – need to appreciate the matrix
• Urban matrix has varying suitability for biodiversity depends on: attributes of matrix & characteristics of organism
using the matrix
• Design of matrix can result in ecosystem services: pollution removal by trees (air & water purification) & mitigation of
UHI
MATRIX QUALITY
• Majority of matrix is residential & green space – high level of impervious surfaces
• Maintaining tree cover improves matrix quality: trees critical to species left in cities
• Structural complexity critical to retain urban avoiding species
• Matrix quality less critical to urban adapted or exploiter species
Improving Matrix Quality
Retaining Large
Trees
• Trees as keystone species - large trees have greater species richness and probability of
breeding than smaller trees
• Habitat, shelter and den sites for bats, birds, reptiles
• Hollows - public risk, but habitat and limit distribution of hollow dependant fauna, need range
of hollow sizes
• Improve connectivity
• Social, cultural and aesthetic importance
Garden
Habitats
• Blue-tongue lizards commonly found in Sydney gardens while other reptiles are absent
• Females are sedentary, males disperse but avoid people, road, pets
• Generally avoid built environments, active during day when people are at work, lives in
untidy areas of garden, retreat to 'hard cover' when threatened
• Generalist omnivores that can exploit food in gardens
ECOSYSTEM SERVICES FROM LARGE GREEN OPEN SPACES: URBAN GOLF COURSES
• Large urban green spaces have high biodiversity value, but varies with vegetation management
• Aim of study: measure biodiversity benefits & ecosystem services provided by urban green spaces
• Measured vegetation variables to determine structural complexity – including biomass and understory volume
o Golf courses have higher structural complexity than gardens & parks and great species richness than
remnants in the case of some species
• Ecosystem services: bees (pollinators), beetles, bats & bugs (pest control), birds (seed dispersal & pest control)
• Bee community changed based on floristic & vegetation structure – most diverse communities & specialised species
in golf courses
• Bats & birds: high number breeding in golf course, bats well adapted to urban areas still high abundance in golf
course
o Link between abundance of bats & insect abundance (based on vegetation complexity) = more important
than presence of large old trees
URBAN GREEN INFRASTRUCTURE MANAGEMENT
• Revegetate with native plants – target out of the way, unused areas
o Encourage natural regeneration by reducing moving and fires
• Weed removal
• Indigenous Gardens: using native/indigenous species in gardens creates stepping stones for habitat & food for
insects
• Improve habitat in gardens & backyards: diversity of habitat features to increase biodiversity value (rocks, leaf litter)
• Retain large trees & coarse woody debris: shelter for nesting & refuge, sites for water, foraging sites
• Supplement scarce resources:
o Beetle banks – provide decaying wood for habitat
o Nest boxes – artificial hollows
Document Summary
Structural complexity critical to retain urban avoiding species. Blue-tongue lizards commonly found in sydney gardens while other reptiles are absent: generally avoid built environments, active during day when people are at work, lives in. Females are sedentary, males disperse but avoid people, road, pets untidy areas of garden, retreat to "hard cover" when threatened: generalist omnivores that can exploit food in gardens. Large urban green spaces have high biodiversity value, but varies with vegetation management. Ecosystem services: bees (pollinators), beetles, bats & bugs (pest control), birds (seed dispersal & pest control) Bee community changed based on floristic & vegetation structure most diverse communities & specialised species in golf courses. Bats & birds: high number breeding in golf course, bats well adapted to urban areas still high abundance in golf course. Link between abundance of bats & insect abundance (based on vegetation complexity) = more important than presence of large old trees.
