LEC 35 - INVASIVE SPECIES

Question 1

can we predict the success of invading species?

Answer 1

yes - for ex. bythotrephes distrib was predicted w 91% accuracy using factors such as lake area, lake depth, chlorophyll a, secchi transparency, etc

Question 2

compared to native species, what makes zebra and quagga mussels so brutal?

Answer 2

ability to take up space - native species hit like 10 per m2, but zebra and quagga mussels can hit several hundred thousand per m2

Question 3

ig its fuck zebra mussels rn

Answer 3

• led to overall decr in diversity richness, but total abundance remained unchanged (literally colonizers)
• super efficient filterers (collectively, said to filter lake erie every seven days)
• shunt pelagic prim prod out of water column, causing incr in light pen and thus favouring benthic prim prod
• biodeposits (gopissgirl) increases food avail for some benthic inverts

Question 4

ontario lake trout vs smallmouth + rock bass

Answer 4

lake trout are traditionally pisciv, but can be ptoniv if necessary, and necessary this was when bass came in, who outcompeted trout for minnows - lake trout were thus forced to become more ptoniv

Question 5

how do we deal w invasive species?

Answer 5

PREEMPTIVE CONTROL IS UR BEST FRIEND

physical controls:
+ easier for macrophyte bc they’re not moving around
- harder for non macrophyte organisms bc they’re moving around

chemical controls (ex. rotenone):
+ efficient
- can harm native species

biological controls:
+ can work
- can harm native species

Question 6

what are some toxicants we need to think about

Answer 6

metals (mercury, cadmium, lead, etc)

chlorinated organics (DDT, PCBs, etc)

hormone/endocrine disruptors (ex. estrogen)

Question 7

is toxin remediation feasible?

Answer 7

yes - its actually very doable

efforts to decr lead, PCBs, and mercury through regulation was found to work

Question 8

what is the difference between bioconcentration and biomagnification?

Answer 8

bioconc: incr of a toxicant in tissue relative to environ

biomag: incr of a toxicant up the trophic cascade

both are related to the substance’s solubility in water

Question 9

are dudes higher in the trophic cascade safer or more vulnerable to biomagnification?

Answer 9

more vulnerable - the higher ur trophic position, the more toxicant gets biomagnified

Question 10

how do hormone disruptors in the water affect FW animals?

Answer 10

ELA were treated w hormone mimics

minnows were most affected - young pop dropped almost immediately, indicating an effect on minnow reprod. following this was a drop in adult pop. this had subsequent effects on the trophic cascade (zpton, ppton, etc)