446 Aquatic Ecology Flashcards Preview

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Flashcards in 446 Aquatic Ecology Deck (279)
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151

trophic downgrading

apex consumers were ubiquitous for my's, extensive cascading effects as diverse as disease, wildfire, carbon sequestration, invasive species, biogeochemical cycles: process, function, resilience

152

trophic cascades: see otter populations

eat sea urchins- sea urchins destroy roots of kelp- kelp bed declines harm many species (home to many species, similar to corals)

153

trophic cascade: sea star

absence of sea star= loss of diversity in tidal community; sea stars increase species diversity by preventing competitive dominance of mussles

154

trophic cascade: Long Lake, Michigan experiment

large mouth bass - prey on minnows-- graze on algae. right side of lake has bass = clear lake, left side has no bass = decrease clarity. bass indirectly reduce phytoplankton, indirectly increase clarity

155

trophic cascade: sharks

without sharks/apex predators don't have complex food web, can't have clear water, can't have coral reefs

156

trophic cascades: Brier Creek

predatory bass extirpate herbivorous minnows, promote growth of benthic algae, alter colour of water

157

trophic cascade: arctic fox

preys on birds, decrease bird population-- decrease nutrient input (poop)-- grasslands turn to tundra

158

trophic cascades: predatory cats

remove large predators-- herbivores increase and 'clean up' forest floor (less leaf litter and forest floor plants)

159

trophic cascade: wolf

wolf-- elk-- more, greener riparian vegetation

160

trophic cascade: wildebeest

eradication of virus-- recovery of native ungulates-- decline of woody vegetation in Serengeti

161

sea otters absent

fish abundance decreased
mussel growth decreased
gulls- diet shift from fish to invertebrates
bald eagles- diet shift-- decrease in mammals, fish; increase in birds

162

trophic cascades: fire

rinderpest (viral) decreases wildebeest which decreases vegetation control which increases fire risk
40% more burn with virus

163

trophic cascade: disease

fishing decreases lobster-- decreases sea urchin density-- increases epidemics
~30% increase in epidemic without fishing

164

trophic cascade: atmosphere

bass decrease minnow, decrease zooplankton, decrease phytoplankton, increase atmospheric C influx

165

trophic cascade: soil

fox decreases seabirds, which decrease soil nutrients

166

trophic cascade: water

spawning salmon decrease particulate suspension, decreases stream particulate load

167

trophic cascade: invasive species

predatory birds decrease non-indigenous spiders

168

trophic cascades: biodiversity

coyotes decrease mesopredators which decrease small vertebrates

169

preceded all other human disturbance

overfishing -- ecological extinction

170

fishing and nile perch

type of fishing determine survivorship (age), survivorship determines prey taken by nile perch

171

nile perch predation on haplochromines

decreasing: no fishing, gill nets, beach seines, gill nets + seines

172

salmon life cycle

freshwater- eggs, rearing of juveniles
estuary- smolt (0-1yr)
ocean- juvenile, growth (1-4yrs)
estuary- returning to freshwater to spawn
freshwater - spawning, death- contribute nutrients

173

importance of salmon in the ocean

orca
harbour seal
commercial fishery

174

importance of salmon in freshwater

sport fishery
cultural fishery
bear, eagle, gull, coyote, otter, raven, crow, trout

175

simplified salmon life cycle

incubation-- fry-- smolt-- adult-- return

176

salmon fry

recently hatched, very young

177

smolt

young salmon, ~2yrs, ready to return to sea, changes to system for saltwater life

178

salmon return related to

size of smolts

179

~2inch smolts

4-8% return rate

180

~6inch smolt

10-20% return rate