Vertebrate of BC Part 2 Flashcards Preview

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Flashcards in Vertebrate of BC Part 2 Deck (484)
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451

impacts of exotics

new parasites, greatest density in disturbed habitat, major impacts in natural land adjacent to disturbed habitat

452

disturbed habitats

urban, roadside, rural properties, agriculture, predator-free zone

453

Introduced Canada geese

intentionally cross-bred in 60's to establish breeding population for harvest, spread exotic grasses (feces), decline native plant species abundance

454

Scott islands

largest aggregation of breeding seabirds in E Pacific ocean south of Alaska

455

changes to scott islands, aliens

large decline in seabird population due to american mink, raccoon (European rabbit also present but not found to have effect)

456

Cassin's Auklet, scott islands

Triangle island, Sartine island, bulk of worlds breeding population of Cassins auklet, selects grass-covered habitat, vegetation changes on these islands reduces reproductive success

457

Haida Gwaii, native vs alien plant species

native ~500
exotic ~140
143/657 = 22%

458

Haida Gwaii, native/nonnative mammals

native 12
introduced 14
14/26 = 54%

459

introduced mammals, haida gwaii

norway rat, raccoon, mink, muskrat, beaver, red squirrel, sitka deer, elk, feral cat, pheasant, tree frog, red-legged frog

460

non-native feedback

introduced plants bring in alien insects bring in higher trophic level aliens...

461

rats and seabirds, Queen Charlottes

seabird colony decline, predation from rats invade burrow-nests, especially ancient Murrelet, present on 18islands, Norway rat replaced black rat on Langara

462

Nestucca oil spill

December 23, 1988
Greys harbour washington, barge cable broke, tug backs into and punctures barge, release 231,000 gallons fuel oil, oil covers 100km WAS, over 200km VI, 56,000 bird deaths known, $5million fine

463

warfarin

sweet-clover, oral anticoagulant, inhibits Vit K formation, hemorrhaging, highly toxic, major global pesticide, odourless, tasteless, 100% mortality, slow death multiple days, internal bleeding and trauma, LD50 1mg/kg/day

464

second-generation super-warfarin

brodifacoum
LD50 0.3mg/kg/day
human death with less than 1% sugarcane mass
long lasting, 6months
worldwide rodenticide

465

eradicating rats, langara island, 1995

bate station: pipe with internal shelf, bated with brodifacoum, every 75-100m in concentric circles
funds: Nestucca oil spill settlement
technique: NZ study
duration: 2years
success, 10's of thousands of rats killed, seabirds back on the rise

466

adverse effect of eradicating rats on Langara

common raven greater than 50% mortality, risks of secondary poisoning, 15% of bald eagles blood tests showed detectable residue but no adverse affects found

467

racoon

formerly absent on HG, mainland and VI
introduced 1940
no predators
significant ooivore of ground nesters
more opportunistic than rats, very successful, swimmers- difficult to remove

468

Sitka deer, HG

1878- 8 introduce
1911- 28 released
1925- 3 released
2005- 150,000
low predation, no predator, no competitor
exponential population growth

469

Deer-vegetation interaction

browse line = height of animal, yearly growth very small below browse line, can't get large, bush like shape on bottom

470

dendrochronology

tree-ring dating

471

Moresby Island dendrochronology

ring width shows large convergence after 1990

472

tree defence

anti-browsers, monoterpene, volatile, physiologically costly, unnecessary without predator, attract wasps (predator of insects)

473

monoterpenes and browsing

lower in heavily browsed trees
(bitter)

474

deer and understory invertebrates

deer-free -- 20yrs of deer -- 50years of deer
significant decrease in abundance and species numbers of inverts (because of decreased vegetation diversity)

475

deer and pollinators

deer-free--20yr--50yr
sig. decrease, no bumblebee on islands with deer greater than 50yr!

476

expected insects and pollinators on islands without deer

would expect highest numbers and diversity because they are the islands closest to the source land

477

deer and parasitoid insects

same pattern.. low plants, low insects with lots of deer (same pattern with songbirds as well)

478

deer impact pathway aboveground

deer browsing- change veg. - reduce understory abundance/diversity- fewer herbivores, pollinators - fewer predators, parasites

479

deer impact pathway on ground

browsing- change veg. - reduce litter and dry soil - fewer detritivorous inverts. - fewer predators

480

Songbirds use of shrubs

fruits
nectar
nest sites
insects