Monday, June 04, 2007

Backyard Biodiversity Project - Zone 17

Part of surveying the plants and animals of Hummingbird Hill is recording all the data. I’ve divided the property into Zones. The Zones are different sizes but each is a type of habitat.

Zone 17 Description

  • Location: Planter in front of house on a North facing slope, from driveway to the eastern property edge. Includes driveway in front of house.
  • Soil Condition: Poor, concrete and gravel over clay
  • Water Availability: Manual hose irrigation and rain
  • Climate: Dry, sun
  • Human Traffic: Minimal, but daily car traffic across driveway
  • Animal Traffic: Minimal canine passing through

I’m interested in Native vs. Exotic species - who is surviving, who is not. Who is feeding on whom. What animals are interacting with which plants. The hardest task is finding a good source for identifiing the small creatures and the “weeds.”

Zone 17 General Notes:
  • Densest populations of animal species were found in specific areas. Dominant species are scale and aphids; exotic cottony cushion scale (Icerya purchasi) [on Native holly cherry] and exotic oleander aphid (Aphis nerii) [on exotic oleander] 170; and Native rose aphid (Microsiphum rosae) 50 [on exotic oleander]. Small milkweed bugs (Lygaeus kalmii) constituted a reproducing population of natives on the ground among the gravel. Spiders were found on the oleander stumps. All other animals were singletons or deceased populations.
  • Dominant plant species is unidentified. Most successful plants are volunteers in cracks of driveway.
  • Exotic snail and crustaceans only represented by deceased bodies possibly due to drought.
  • The greatest species diversity was among spiders, 7 species and insects 10 species.
  • 31 species identified - 25 animals, 6 plants
  • Greatest population - cottony cushion scale (Icerya purchasi) 200 individuals and yet-identified volunteer ground cover, 34 plants.
  • Currently no birds, reptiles or mammals live in this Zone, though birds have nested here in the past.
  • Animals out number plants. Natives out number Exotics.
Native Insects:
  1. rose aphid, Microsiphum rosae, 50 (feeding on oleander)
  2. California carpenter bee, Xylocopa californica, 1
  3. small milkweed bug, Lygaeus kalmii, 67
  4. gray bird grasshopper, Schistocerca nitens, 1 (body parts left by predator)
  5. black gnat, Bradysia impatiens, 1
Exotic Insects:
  1. oleander aphid, Aphis nerii, 170 (feeding on oleander)
  2. Argentine ant, Iridomyrmex humilis, 1 (one the garage door)
  3. cottony cushion scale, Icerya purchasi, 200 (feeding on holly leaf cherry)
  4. oleander scale, Aspidiotus nerii, 1 (feeding on oleander)

Not yet identified:
  1. long-legged fly, Dolichopodidae ssp type, 1
Native Spiders and Crawlies:
  1. round snail, Discus whitneyi, 3 dead
  2. soil mite, Oribatei spp., 1
  3. corner spider, Hololena curta, 3
  4. trashweb spider, Cyclosa turbinata, 10
Exotic Spiders and Crawlies:
  1. brown garden snail, Helix aspers, 6 dead
  2. common pill bug, Armadillidium vulgare, 4 dead
Not yet identifed Spiders and Crawlies:
  1. snail, cone type, longer than wide, 1 dead
  2. spider unidentified, ‘1 mm’ brown, 1
  3. spider unidentified, ‘3 mm’ brown no web, long front legs, 2
  4. spider unidentified, ‘ant-sized’ black, 1
  5. spider unidentified, ‘ant-sized’ black with web, 1
Native Birds:
  1. band-tailed pigeon, Columba fasciata, feather
  2. California towhee, Pipilo crissalis, 1
Native Mammals:
  1. desert cottontail, Sylvilagus audubonii, scat
Exotic Mammals:
  1. fox squirrel, Sciurus niger, 1
Native Plants:
  1. sow thistle, Sunchus ssp., 15 (volunteer in driveway cracks)
  2. spotted spurge, Euphorbia maculata, 1 (volunteer in driveway cracks)
  3. annual bluegrass, Poa annua, 2 (volunteer in driveway cracks)
Not yet identified:
  1. ground cover with white flowers, 34 (volunteer in driveway cracks)
Exotic shrub:
  1. oleander, Nerium oleander, 4 (recently cut to the ground)
Native tree:
  1. holly leaf cherry, Prunus ilicifolia ilicifolia, 2 (volunteers)

No comments: