Invasive Species September 5 th, 2007

Announcements:  Check out Case Studies posted on website (if you forgot which group you are in, scroll through to find your name, or ask me) Come prepared for class discussion tomorrow  Background Field Trip Questions: now posted  Field Trip Waiver Forms: I need you to sign them  Field final: will be passed out tomorrow

Summary of Monday: How do communities change? Succession Primary vs. Secondary Who wins at the beginning? Who winds at the end? Facilitation: biotic/abiotic interactions Early colonizers vs. Pine vs. Oak Grasses on sand dunes, eelgrass Acceleration Climax communities? Plant vs.Animal Succession? Intermediate Disturbance Hypothesis Role of fire in Chaparral Biome

Why study invasive species? Invasive species are the second greatest threat to conservation of biodiversity economic consequences (good and bad) human health consequences

Invasive Species Glossary native: an organism that is living in its home environment Endemic: organism that is only found in/confined to a particular location exotic non-native originally from a different location foreign/alien naturalized: a non-native that has become a part of its new environment invasive: a non-native that has spread to become a dominant member of its new environment weed: an invasive species of plant that causes environmental or economic problems - Noxious weed: legally designated as a pest

How do non-native species arrive? Accidentally seeds parasites unintended cargo Deliberately food timber pets biocontrol Data source: Eurostat. Source of figure: CNT, 2004 Data source: US Department of Transportation, 2004

Who are these invaders? Plants Animals Microorganisms

What makes an invader successful? r-strategists grow quickly produce many offspring short generation time good dispersion generalists: highly adaptable to new conditions broad geographic range in native environment broad diet It has not coevolved with members of its new environment What made the green crab successful?

What makes a community vulnerable to invasion? human disturbance early succession climate similar to native habitat absence of predators or pathogens wrong ones for the invader no predators or pathogens at all - islands

What do invasive plants do? Change ecosystem structure fire suppression/enhancement grassland  shrubland And vice-versa Change nutrient cycling Spartina alterniflora Change physical structur of landscape European beachgrass use up limiting resources, such as water, light riparian zone  desert woodland  kudzu-dominated land

Grassland to shrubland Changes fire regime!

Shrubland to Grassland Changes fire regime!

Woodland to Kudzuland Can you guess its strategy?

Riparian zone to desert

Local Invaders: Castor Bean, Fennel Pampasgrass, Iceplant…

What do invasive animals do? Change foodweb structure Hyperpredation drive out native competitors and prey

A case study: zebra mussels native to Russian lakes introduced to North America in 1985 from bilge of a ship after <1 year, can produce 1,000,000 eggs large colonies clog pipes very efficient filterers clear water eliminate native species

Zebra mussel range map

Microorganisms: virus, fungi, bacteria

Invasive Plant and Animal Mutualism +

Can an invasive be unwanted at times, and desirable other times?

Management Options  Do nothing  Understand life strategy Vulnerabilities, limiting factor  Predict where it will invade, rate of spread, during what time periods…. Remote sensing Mathematical models!  ERADICATE!

Eradication  Physical control  Chemical control  Thermal control  Biological control Predator Virus Grazing Coalition Drops Black Rat Poison on Anacapa Island by Rebecca Turek - Staff Writer Thursday, December 6, 2001

Biological control: lessons from the Outback  Cane toads  Rabbits 1950’s: myxoma virus 1990’s: Calcivirus  Success stories: Schisto.

How can we avoid invasive species and preserve biodiversity?  “Co-habitable” land use Land uses consistent with biota –Give up the green lawn! –Organic/crop rotation based agriculture (but what is the cost?)  Habitat enhancement Variation of landscape Restore disturbance regimes  Re-introduction  Laws and Regulations

Pop Quiz! Which plant/animal would you say is the MOST invasive???

Questions to Ponder:  How long do you have to inhabit an area to be a native?  What point in time should we restore to?  Is fighting invasives a losing battle? What are the costs of doing nothing?

Where is biodiversity loss most prominent? Conservation International: Biodiversity Hotspots CI quantified by number of endemic plant species and threat

Assessing Biodiversity  Indicator species: Species that are present only under strict environmental conditions Can be used to detect healthy/unhealthy ecosystems Example: steelhead, certain diatoms  Species diversity/richness: number of species in sample  -diversity: number of species within a single habitat type  -diversity: difference in species composition between habitats  Species evenness: equality of relative abundance Unevenness might indicate unhealthy ecosystem  Biodiversity Index

Shannon-Wiener Biodiversity Index Where: H = the Shannon-Wiener biodiversity index p i = proportion of each species in the sample (relative abundance) log e = the natural log of p i s = the number of species in the community (species richness) H( Community II ) = -(.3*ln(.3)+.07*ln(.07)+.1*ln(.1)+.5*ln(.5)+.03*ln(.03))

How to Protect Biodiversity?  Protect Species Endangered Species Act Classic Fisheries Managment  Protect Habitat Reserves Conservation Easements Marine Reserves

Species Protection  Minimum Viable Population (MVP)  Inbreeding, genetic drift  Genetic bottleneck  Minimum Viable Area—habitat protection

Genetic bottleneck -Population loses much of its genetic diversity from a population decline Most genetic diversity is retained

Which Species to Protect?  Umbrella species  Flagship species  Keystone species

Habitat Protection: Reserves  One large or many small?  Shape?  Connectivity?

SLOSS Debate: Single Large vs. Several Small Species-area curve Management implications: Small reserves: area = speciesSmall reserves: area = species As area increases, diminishing returnsAs area increases, diminishing returns To consider: Genetic exchange Extinction events Edge effects Future Pressures Cost/Flexibility

Reserves…. Size matters!

Shape Matters too! Cores and Buffers:

Connectivity: Nodes and Corridors Is connectivity important in MPA’s?

Habitat Conservation Management Tools  Conceptual diagrams  Collaboration (with stakeholders, community)  Mathematical/computer models  GIS (Geographic Information Systems)  Remote sensing  Environmental Impact Reports

The new trend…… Ecosystem Based Management (EBM) "EBM looks at all the links among living and nonliving resources, rather than considering single issues in isolation... Instead of developing a management plan for one issue..., EBM focuses on the multiple activities occurring within specific areas that are defined by ecosystem, rather than political, boundaries." US Ocean Commission Report,