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Lecture 4: Dispersal and Habitat Selection. EEES3050. Outline. Background on dispersal Introduction to invasive species Zebra mussel example Habitat selection. Why do species live where they do?. Or rather…why are they not in particular places? Dispersal Habitat Selection Biotic factors
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Outline • Background on dispersal • Introduction to invasive species • Zebra mussel example • Habitat selection
Why do species live where they do? • Or rather…why are they not in particular places? • Dispersal • Habitat Selection • Biotic factors • Abiotic factors
Types of Movement • Local: e.g. foraging • Migration: birds or elk • synchronized, directional mass movement of individuals • Dispersal: • nonsynchronized, non-directional movement of individuals
Costs and benefits of migration • Costs: • Increased mortality • Energy expenditure • Benefits: • Breeding • Escape mortality • Resource gain
Patterns of migration • Types of migration • Long-distance: birds, reindeer, whales • Seasonal movements among habitats: elk, deer • Tides: constant habitat changing site • 'One return journey' migration • eels, salmon, monarch butterfly • 'One way migration: a European butterfly
Dispersal • Why? • Home can be a dangerous place • Dispersal as escape and discovery • exploratory (mobile) discovery • nonexploratory (sessile) discovery: propagules • plants: cocoanuts & dandelions • invertebrates: spiders
Why do species disperse? • Balance between: • Staying put in a suitable habitat with the small probability of out competing others and reproducing. • Taking off with the low probability of landing somewhere else that is suitable and then reproducing.
Dispersal • Passive dispersal by an active agent • seeds, fruits • phoresey: beetles & mites, remoras & sharks
Costs and constraints of dispersal • Cost: • energy and nutrients required for structures reduces the number of propagules produced • Ability to disperse (vs. survival) and capital investment: • weight of seed is directly related to viability and inversely related to ability to disperse
Types of Dispersal • Diffusion • Gradual movement of a population across hospitable terrain • Jump dispersal • Movement across large distances – usually across uninhabitable terrain.
Invasion Biology • What is an “invasive” species? • A non-native species that was released (on purpose or accidentally) and is affecting the environment or economy in a “negative” manner. • Sometimes called “introduced” species. • Usually an “invasive” species is one that is causing harm. • Other terms, nuisance, non-native, non-indigenous, … Suggested reading The Ecology of Invasions by Animals and Plants by C.S. Elton
Invasion Process Source Region of Species Pathway quantification Transport/Survival in Pathway Statistical & Population models Establishment Dispersal/population models AbundanceSpread Statistical models Impact
Assessing the dispersal potential of zebra mussels: Evaluating the ecological and economic value of the 100th Meridian Initiative Jonathan M. Bossenbroek, Ph.D. University of Toledo Lake Erie Center Dept. of Earth, Ecological and Env. Sciences In Collaboration with David Lodge, Dave Finnoff and Jean-Daniel Saphores,
100th Meridian initiative Columbia River Basin Colorado River Basin
Assessing the Potential Impacts of Zebra Mussels • Background on Zebra Mussels • Spread • Impacts • Environmental • Economic • Dispersal • Human-mediated • Natural
Assessing the Potential Impacts of Zebra Mussels • Background on Zebra Mussels • Spread • Impacts • Environmental • Economic • Dispersal • Human-mediated • Natural
NEWS RELEASE WASHINGTON DEPARTMENT OF FISH AND WILDLIFE 600 Capitol Way North, Olympia, Washington 98501-1091 Internet Address: http://wdfw.wa.gov May 25, 2004 Contact: Pam Meacham, 360-902-2741 Or Mike Whorton, 509-456-3182 Zebra mussels discovered at Washington-Idaho border SPOKANE – Zebra mussels, invasive species that could harm Washington fish and wildlife and damage hydroelectric dams and public water systems, were discovered this month on a large boat being trailered cross-country by commercial vehicle, the Washington Department of Fish and Wildlife (WDFW) reported today. Despite the successful discovery at the Washington-Idaho border, WDFW officials are concerned that zebra mussels could be slipping in on smaller boats that are not required to stop at highway weigh stations. Zebra mussels, fingernail-size freshwater mollusks native to the Black, Caspian and Aral Seas, were first introduced to the Great Lakes in 1986 in the ballast water of transoceanic ships. They can spread quickly, altering entire ecosystems of some waters by smothering native mussels and consuming food sources of other fish and wildlife.
Date: 06/08/04 Contact: Geoffrey Schneider Phone: (702) 486-5127 MENACING MOLLUSKS DISCOVERED ON A HOUSEBOAT AT LAKE MEADBy: Rory Aikens, Arizona Game & Fish Department Zebra mussels, which have been devastating in the Great Lakes, were discovered on a 54-foot houseboat from Kentucky that was attempting to launch at Temple Bar on Lake Mead over the Memorial Day holiday weekend. The marina is located on the shoreline of Temple Basin on the Arizona side of the lake. Arizona and Nevada wildlife officials say the zebra mussel discovery highlights the need for all boaters to be vigilant and conscientious when taking their crafts from one waterway to another, even when its within the state.
Assessing the Potential Impacts of Zebra Mussels • Background on Zebra Mussels • Spread • Impacts • Environmental • Economic • Dispersal • Human-mediated • Natural
Zebra Mussel Basics • Small bi-valve • Not like native clams • Attaches to things • Origin: Ponto-Caspian sea region • Very high reproductive rates. • Over 40,000 eggs can be laid in a reproductive cycle and up to one million in a spawning season • Filter feeders
Mussel Beach Courtesy of Dr. Clifford Kraft
Ecological Impacts Courtesy of Dr. Clifford Kraft
Economic Impacts Courtesy of Dr. Clifford Kraft
U.S. Army Corp of Engineers Potential Impacts in Columbia River • Columbia River Basin • 67 municipalities • Fish passage facilities • 39 BOR projects • 72 dams, dikes and diversions • 4,700 miles of canals • Grand Coulee Dam is the largest hydroelectric dam in North America • Twelve of the worlds largest pumps remove water from the Franklin Delano Roosevelt reservoir
Assessing the Potential Impacts of Zebra Mussels • Background on Zebra Mussels • Spread • Impacts • Environmental • Economic • Dispersal • Human-mediated • Natural
Dispersal • Zebra mussel spread from 1986 to present • Patterns of Invasion • Long-distance Dispersal • Importance of Navigable Waterways • Gravity Models • Spread via diffusion • Importance of streams
Modes of Dispersal • Natural Dispersal downstream • Shipping • Recreational Boating
Reservoirs in OK and KS in Verdigis River basin Inland Lake Distance to Great Lakes
Inland lake infestation rates From Johnson, Bossenbroek & Kraft. 2006 Biological Invasions
3 Possible Explanations • Outreach • Zebra mussel fatigue • Decreasing probabilities of new infestations
Dispersal • Zebra mussel spread from 1986 to present • Patterns of Invasion • Long-distance Dispersal • Importance of Navigable Waterways • Gravity Models • Spread via diffusion • Importance of streams