Lec 13: Effects of Weather and Accidents on Wildlife

how does weather effect wildlife?

direct mortality, foraging efficiency, risk of depredation, reproduction, migration

weather and direct mortality: hot and cold

animals can get either too hot or too cold and die (ex: Florida Manatees dying from cold, Sonoran Pronghorn dying to a heat wave)

weather and direct mortality: ovipary

oviparous species experience hatchling anomalies when exposed to extreme temperatures

weather and direct mortality: extreme weather events

- extreme weather events like hailstorms cause direct mortality, especially to smaller vertebrates

- also cause nest mortality

what species are most impacted by weather caused mortality?

usually only impactful for species/populations with severely restricted ranges or with limited resources

weather and foraging: water freezing

species that forage in water are more prone to mortality when water freezes over; decrease in resources and increase of competition

weather and foraging: differing metabolisms

species with differing metabolisms are impacted by weather when occupying similar trophic niches; endotherms can continue to forage in weather temps that ectotherms cannot

weather and predation

weather events often increase probability of depredation (rain or wind makes it easier for predators to sneak up on prey; rain or snow can obscure prey visual senses)

weather and reproduction: eggs

eggs are vulnerable to weather; not easily moved/restrained to nests and incapable of self-thermoregulation

weather and reproduction: neonates/newborns

newborns have limited thermoregulatory abilities; intense cold and heat can cause mass mortality (winter deaths in fawns)

weather and migration: resources

weather events are not typically dangerous in a species home range, but can become so when migrating to new areas (have knowledge of shelter and resource location in home range, but not in new areas)

weather and migration: expending energy

extreme weather events can cause higher than normal energy expenditures (birds flying into head winds, causes exhaustion)

weather patterns often impact reproductive rates

- especially true in the spring

- winter weather influences annual variation in survival for many species

- arid regions heavily tied to precipitation phenology

predicted rise in temperature by 2050

rise of 1 - 2 degrees Celsius

how will climate change affect wildlife?

danger for polar adapted species (plants and animals)

will climate change outpace adaptability?

trophic mismatches are likely; gain and loss of home ranges differing by species

accidental deaths

difficult to accurately estimate for wildlife; most common early and late in life (Bighorn sheep miss-stepping and falling off a cliff)

accidental deaths caused by humans

oil ponds, communication towers, power lines, wind turbines, windows, cars and trucks, fences, aircraft, trains, and household wildlife control

oil ponds

retention ponds are by products of pumping petroleum products; often attract migratory birds, especially waterfowl, that see it as a water source

communication towers

more than 50,000 communication towers >66 m tall in the U.S.; cause a lot of mortality by having a high rate of bird collisions in inclement weather (often hit the guidelines rather than the tower itself)

power lines

mortality through collisions or electrocution

wind turbines

great for environment, bad for wildlife (direct mortality, habitat fragmentation); solar power fields have similar results in terms of fragmentation

direct mortality from wind turbines

direct collision from bird, turning of turbines creates pressure cells that can kill bats flying through (lungs explode from pressure, not typically killed by collision)

windows

often recognized as the 2nd greatest source of human caused mortality for birds; influenced by weather, type of glass, glass orientation, and proximity to bird feeders

cars and trucks

ungulates receive the most attention in terms of vehicle collisions, though collisions do affect other taxa

fences

restrict animal movement through seemingly open terrain; animals can easily get tangled trying to go over, under, or through fences, or can be electrocuted

aircraft

15,799 reports of wildlife killed by civil aircraft in 2018; most collisions are never reported so mortality is likely higher

trains

collisions with large mammals are often the ones reported; collisions with smaller animal likely go unnoticed

household wildlife control

>40% of houses the the largest U.S. urban centers take pest control actions; small animals are the usual targets