1)Invasive plants – What are they? b) Ecological definitions and characterizations Nevada’s Coordinated Invasive Weed Strategy (

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 competitiveCause environmental degradation ExoticEasily spread Highly aggressiveAre difficult to control Cause 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” oSpecies that have potential to cause greatest impact on Nevada’s ecosystem and economic well being oNot all are on noxious weed list oIncludes: Red bromeCheatgrass WhitetopsKnapweeds Yellow starthistleThistles Rush skeletonweedMedusahead SaltcedarWatermilfoil

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed Strategy The Nature Conservancy ( 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 StrategyNature Conservancy Davis & Thompson (2000) Ecologists have used different words for invasive species AlienExotic InvasiveNon-indigenous ImportedWeedy IntroducedNon-native ImmigrantColonizer Naturalized

NV Coordinated Invasive Weed StrategyNature 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 StrategyNature 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 StrategyNature 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 StrategyNature 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 StrategyNature 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 8 ways to be a colonizer SC = successional colonizers

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature 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 colonizer SC = successional colonizers NNC = novel, noninvasive colonizers

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature 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 SC = successional colonizers NNC = novel, noninvasive colonizers NIC = novel, invasive colonizers

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature 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 invader SC = successional colonizers NNC = novel, noninvasive colonizers NIC = novel, invasive colonizers

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Naturalization and invasion of alien plants: concepts and definitions. Diversity and Distributions 6: (assigned reading)

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Process Introduction Home range Introduced area

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) ProcessBarrier IntroductionGeographic Home range Introduced area Geographic

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) ProcessBarrierIf successful IntroductionGeographicAlien Home range Introduced area Geographic

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) ProcessBarrierIf successful IntroductionGeographicAlien NaturalizationEnvironmentalCasual Home range Introduced area Geographic Environment

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) ProcessBarrierIf successful IntroductionGeographicAlien NaturalizationEnvironmentalCasual ReproductiveNaturalized Home range Introduced area Geographic ReproduceEnvironment

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) ProcessBarrierIf successful IntroductionGeographicAlien NaturalizationEnvironmentalCasual ReproductiveNaturalized InvasionDispersalInvasive Home range Introduced area Disturbed area Natural area Geographic ReproduceEnvironment Disperse

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien 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 StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien 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.) otypically >100 km or past a known geographic barrier

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien 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 StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien 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 Historical evidence

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien 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 Historical evidence Habitat

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien 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 Historical evidence Habitat Geographic distribution

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien 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 Historical evidence Habitat Geographic distribution Frequency of naturalization

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien 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 evidenceGenetic diversity Historical evidence Habitat Geographic distribution Frequency of naturalization

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien 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 evidenceGenetic diversity Historical evidenceReproductive pattern Habitat Geographic distribution Frequency of naturalization

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien 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 evidenceGenetic diversity Historical evidenceReproductive pattern HabitatPossible means of introduction Geographic distribution Frequency of naturalization

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien 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 evidenceGenetic diversity Historical evidenceReproductive pattern HabitatPossible means of introduction Geographic distributionOligophagous insects Frequency of naturalization

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien plants Casual 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 StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien plants Casual alien plants Naturalized 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 StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien plants Casual alien plants Naturalized plants Invasive plants = naturalized plants that produce reproductive offspring (often in largenumbers) 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 StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien plants Casual alien plants Naturalized plants Invasive plants Increasing level of reproductive success

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien plants Casual alien plants Naturalized plants Invasive plants Weeds = plants that grow in sites where they are not wanted; usually have economic or environmental effects Increasing level of reproductive success

1)Invasive plants – What are they? b) Ecological definitions and characterizations NV Coordinated Invasive Weed StrategyNature Conservancy Davis & Thompson (2000) Richardson et al. (2000) Processes and barriers Definitions Alien plants Casual alien plants Naturalized plants Invasive plants Weeds Transformers = subset of invasive plants that change ecosystems Increasing level of reproductive success

1)Invasive plants – What are they? a) State and Federal laws and regulations Important from legal perspective b) Ecological definitions and characterizations Important for understanding the ecological processes and consequently, how to prevent and control invasions