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ISI: Invasive Species Investigation CRIME SCENE: LAKE MEAD Breaking news: A new kind of mussel is found in Lake Mead. ISI: Invasive Species Investigation Grissom Says: FOLLOW THE EVIDENCE!
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CRIME SCENE: LAKE MEAD Breaking news: A new kind of mussel is found in Lake Mead.
ISI: Invasive Species Investigation Grissom Says: FOLLOW THE EVIDENCE! For ISI: The “evidence” leads us to important information about: Identity, Impacts, Pathways, and Solutions.
The investigation begins:IDENITY? • Evidence: a specimen from the crime scene. • Analysis method: Attention to detail. Taxonomic identification.
The investigation continues:BACKGROUND CHECK Knowledge of habitat and life history critical to understanding IMPACTS
BACKGROUND CHECKQuagga Mussel Biology • Voracious filterfeeders. They remove particles from the water column, increasing water clarity. • Accumulate environmental contaminants in their tissues. • Attach to most substrates including sand, silt, and harder substrates. • Quagga mussel prefers the deeper, cooler water as compared to zebra mussels. • They can stay alive for several days out of water in cool, moist conditions. • High fecundity: producing up to 1 million eggs per year!
BACKGROUND CHECKQuagga mussel habitat (a mini-lesson on limnology) Abiotic factors that structure aquatic ecosystems: temperature, oxygen, sunlight
The investigation continues:UNDERSTANDING PATTERNS IN ECOSYSTEMS Photic zone Aphotic zone
What are some potential IMPACTS of quagga mussels on aquatic ecosystems? What evidence of impact would we look for?
Evidence of IMPACTS? ISI tool: analysis of patterns in ecosystems (biotic and abiotic variables) Possible biotic patterns? Chlorophyll a Possible abiotic patterns? Light penetration
Abiotic evidence: Secci Depth (water clarity) Zebra mussels detected
Biotic Evidence: Chloropyll a patterns Zebra mussel detected
PATHWAYS? Problem: Distribution of species keeps expanding. How did it get into Lake Mead?
ISI: Summary Studying invasive species is much like studying a crime scene. Scientists use “evidence” • knowledge of the species, • patterns in ecosystems, • observations from the field to understand its Identity, Impacts, Pathways, and Solutions. “The evidence never lies”
PATHWAYS? Analysis: Understanding a species life cycle can help us deduce invasion pathways.
PATHWAYS? Evidence: Adult mussels and veligers are found in ballast water, on motor boats, and in water from fish hatcheries.