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1) Invasive plants – What are they?b) Ecological definitions and characterizations
Nevada’s Coordinated Invasive Weed Strategy (http://agri.nv.gov/nwac/weedplan_p.htm)
1) Invasive plants – What are they?b) Ecological definitions and characterizations
Nevada’s Coordinated Invasive Weed Strategy• Prepared by Nevada Weed Action Committee (NV Dept. Ag)• Included local, state, and federal agencies/governments; NCE;
private sector
1) Invasive plants – What are they?b) Ecological definitions and characterizations
Nevada’s Coordinated Invasive Weed Strategy• Nevada Weed Action Committee• Uses USDA definition of noxious weeds: “species of plants that
cause disease or are injurious to crops, livestock or land, and thus are detrimental to agriculture, commerce or public health”
1) Invasive plants – What are they?b) Ecological definitions and characterizations
Nevada’s Coordinated Invasive Weed Strategy• Nevada Weed Action Committee• Noxious weed definition• Invasive weeds often share characteristics such as
Highly competitive Cause environmental degradationExotic Easily spreadHighly aggressive Are difficult to controlCause economic lossAugment wildfires
1) Invasive plants – What are they?b) Ecological definitions and characterizations
Nevada’s Coordinated Invasive Weed Strategy• Nevada Weed Action Committee• Noxious weed definition• Invasive weed characteristics• “Species of concern”
o Species that have potential to cause greatest impact on Nevada’s ecosystem and economic well being
o Not all are on noxious weed listo Includes:
Red brome CheatgrassWhitetops KnapweedsYellow starthistle ThistlesRush skeletonweed MedusaheadSaltcedar Watermilfoil
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy
The Nature Conservancy (http://tncweeds.ucdavis.edu/common.html)Invasive species are:• Spread from human settings into wild• Once wild, continue to reproduce• Displace native species; reduces biodiversity• Usually non-native
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature Conservancy
Davis & Thompson (2000)• Ecologists have used different words for invasive species
Alien ExoticInvasive Non-indigenousImported WeedyIntroduced Non-nativeImmigrant ColonizerNaturalized
NV Coordinated Invasive Weed Strategy Nature Conservancy
Davis & Thompson (2000)• Ecologists have used different words for invasive species• Nomenclature based on 3 major colonization concepts
Dispersal: Short Long
1) Invasive plants – What are they?b) Ecological definitions and characterizations
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature Conservancy
Davis & Thompson (2000)• Ecologists have used different words for invasive species• Nomenclature based on 3 major colonization concepts
Dispersal: Short Long
Uniqueness: Common Novel Common Novel
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature Conservancy
Davis & Thompson (2000)• Ecologists have used different words for invasive species• Nomenclature based on 3 major colonization concepts
Dispersal: Short Long
Uniqueness: Common Novel Common Novel
Impact: Small Great Small Great Small Great Small Great
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature Conservancy
Davis & Thompson (2000)• Ecologists have used different words for invasive species• Nomenclature based on 3 major colonization concepts
Dispersal: Short Long
Uniqueness: Common Novel Common Novel
Impact: Small Great Small Great Small Great Small Great
• 8 ways to be a colonizer
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature Conservancy
Davis & Thompson (2000)• Ecologists have used different words for invasive species• Nomenclature based on 3 major colonization concepts
Dispersal: Short Long
Uniqueness: Common Novel Common Novel
Impact: Small Great Small Great Small Great Small Great
SC SC SC SC
• 8 ways to be a colonizerSC = successional colonizers
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature Conservancy
Davis & Thompson (2000)• Ecologists have used different words for invasive species• Nomenclature based on 3 major colonization concepts
Dispersal: Short Long
Uniqueness: Common Novel Common Novel
Impact: Small Great Small Great Small Great Small Great
SC SC NNC SC SC NNC
• 8 ways to be a colonizerSC = successional colonizersNNC = novel, noninvasive colonizers
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature Conservancy
Davis & Thompson (2000)• Ecologists have used different words for invasive species• Nomenclature based on 3 major colonization concepts
Dispersal: Short Long
Uniqueness: Common Novel Common Novel
Impact: Small Great Small Great Small Great Small Great
SC SC NNC NIC SC SC NNC NIC
• 8 ways to be a colonizerSC = successional colonizersNNC = novel, noninvasive colonizersNIC = novel, invasive colonizers
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature Conservancy
Davis & Thompson (2000)• Ecologists have used different words for invasive species• Nomenclature based on 3 major colonization concepts
Dispersal: Short Long
Uniqueness: Common Novel Common Novel
Impact: Small Great Small Great Small Great Small Great
SC SC NNC NIC SC SC NNC NIC
• 8 ways to be a colonizer, but only 2 ways to be an invaderSC = successional colonizersNNC = novel, noninvasive colonizersNIC = novel, invasive colonizers
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000) Naturalization and invasion of alien plants: concepts and definitions. Diversity and Distributions 6:93-107 (assigned reading)
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)
Processes and barriers
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)ProcessIntroduction
Home range
Introducedarea
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)Process BarrierIntroduction Geographic
Home range
Introducedarea
Geographic
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)Process Barrier If successfulIntroduction Geographic Alien
Home range
Introducedarea
Geographic
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)Process Barrier If successfulIntroduction Geographic AlienNaturalization Environmental Casual
Home range
Introducedarea
Geographic
Environment
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)Process Barrier If successfulIntroduction Geographic AlienNaturalization Environmental Casual
Reproductive Naturalized
Home range
Introducedarea
Geographic
ReproduceEnvironment
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)Process Barrier If successfulIntroduction Geographic AlienNaturalization Environmental Casual
Reproductive NaturalizedInvasion Dispersal Invasive
Home range
Introducedarea
Disturbedarea
Naturalarea
Geographic
ReproduceEnvironment
Disperse
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plants = plant taxa in a given area whose presence is due to
intentional or accidental introduction as a result of human activity
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plants = plant taxa in a given area whose presence is due to
intentional or accidental introduction as a result of human activity
How determine?• Disjunct geographic range (Richardson et al.)
o typically >100 km or past a known geographic barrier
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plants = plant taxa in a given area whose presence is due to
intentional or accidental introduction as a result of human activity
How determine?• Disjunct geographic range (Richardson et al.)• 9 types of evidence (Schwartz in Luken & Thieret 1997)
Fossil evidence
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plants = plant taxa in a given area whose presence is due to
intentional or accidental introduction as a result of human activity
How determine?• Disjunct geographic range (Richardson et al.)• 9 types of evidence (Schwartz in Luken & Thieret 1997)
Fossil evidenceHistorical evidence
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plants = plant taxa in a given area whose presence is due to
intentional or accidental introduction as a result of human activity
How determine?• Disjunct geographic range (Richardson et al.)• 9 types of evidence (Schwartz in Luken & Thieret 1997)
Fossil evidenceHistorical evidenceHabitat
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plants = plant taxa in a given area whose presence is due to
intentional or accidental introduction as a result of human activity
How determine?• Disjunct geographic range (Richardson et al.)• 9 types of evidence (Schwartz in Luken & Thieret 1997)
Fossil evidenceHistorical evidenceHabitatGeographic distribution
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plants = plant taxa in a given area whose presence is due to
intentional or accidental introduction as a result of human activity
How determine?• Disjunct geographic range (Richardson et al.)• 9 types of evidence (Schwartz in Luken & Thieret 1997)
Fossil evidenceHistorical evidenceHabitatGeographic distributionFrequency of naturalization
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plants = plant taxa in a given area whose presence is due to
intentional or accidental introduction as a result of human activity
How determine?• Disjunct geographic range (Richardson et al.)• 9 types of evidence (Schwartz in Luken & Thieret 1997)
Fossil evidence Genetic diversityHistorical evidenceHabitatGeographic distributionFrequency of naturalization
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plants = plant taxa in a given area whose presence is due to
intentional or accidental introduction as a result of human activity
How determine?• Disjunct geographic range (Richardson et al.)• 9 types of evidence (Schwartz in Luken & Thieret 1997)
Fossil evidence Genetic diversityHistorical evidence Reproductive patternHabitatGeographic distributionFrequency of naturalization
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plants = plant taxa in a given area whose presence is due to
intentional or accidental introduction as a result of human activity
How determine?• Disjunct geographic range (Richardson et al.)• 9 types of evidence (Schwartz in Luken & Thieret 1997)
Fossil evidence Genetic diversityHistorical evidence Reproductive patternHabitat Possible means of
introductionGeographic distributionFrequency of naturalization
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plants = plant taxa in a given area whose presence is due to
intentional or accidental introduction as a result of human activity
How determine?• Disjunct geographic range (Richardson et al.)• 9 types of evidence (Schwartz in Luken & Thieret 1997)
Fossil evidence Genetic diversityHistorical evidence Reproductive patternHabitat Possible means of
introductionGeographic distribution Oligophagous insectsFrequency of naturalization
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plantsCasual alien plants = alien plants that flourish (and even occasionally
reproduce), but do not form self-replacing populations. Continued presence depends on re-introductions.
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plantsCasual alien plantsNaturalized plants = alien plants that reproduce consistently and
sustain populations over many life cycles without direct intervention by humans
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plantsCasual alien plantsNaturalized plantsInvasive plants = naturalized plants that produce reproductive
offspring (often in large numbers) at considerable distance from parent plants
>100m & <50 years for seed dispersing species>6 m & >3 years for vegetatively reproducing species
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plantsCasual alien plantsNaturalized plantsInvasive plants
Increasing level ofreproductive success
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plantsCasual alien plantsNaturalized plantsInvasive plants
Weeds = plants that grow in sites where they are not wanted; usually have economic or environmental effects
Increasing level ofreproductive success
1) Invasive plants – What are they?b) Ecological definitions and characterizations
NV Coordinated Invasive Weed Strategy Nature ConservancyDavis & Thompson (2000)
Richardson et al. (2000)• Processes and barriers• DefinitionsAlien plantsCasual alien plantsNaturalized plantsInvasive plants
WeedsTransformers = subset of invasive plants that change ecosystems
Increasing level ofreproductive success