Non-native Invasive Species

Transcription

1 Non-native Invasive Species

2 Quiz: Mack et al List and describe two examples of hypotheses about why a community might be vulnerable to invasion.

3 Vocab: Mack et al Allelopathy chemical defense of plants in soils Cogener Species of the same genus Stochastic - random

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6 What is an Invasive Species? Non-native Capable of surviving without direct help from people ( established or naturalized ) Spreading away from sites of initial establishment Often with negative ecological and economic consequences

7 Stages of Invasion Risk Lockwood et al., 2007

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9 Stop invasive plants early Strayer, 2009

10 Stages of invasion Lockwood et al., 2007

11 Why are non-native species introduced?

12 Why are non-native species introduced? Deliberately Horticulture trade, pet trade American Acclimatization Society 60% of non-native plants in the U.S. were likely deliberately introduced (Mack & Erneberg, 2002)

13 Deliberate introductions of animals Europe to N. America N. America to Europe Jeschke & Strayer, 2005

14 Why are non-native species introduced? Deliberately Accidentally Seed contaminants Ballast water discharge Packing/shipping materials APHIS inspects about 5% of shipping containers for pests

15 Accidental introductions of insects Live plant imports are the primary pathway for forest insect and pathogen invasions in the U.S. Contaminated shipments ( ) An estimated 12% of international imports are contaminated by non-native insects Citrus longhorned beetle exit hole in a Maple shipment

16 Human introduction is VERY different from historic introduction Ricciardi, 2007

17 Human introduction is VERY different from historic introduction Hawaii: 1,000,000 times higher rate of introduction Ricciardi, 2007

18 Stages of invasion Lockwood et al., 2007

19 Why might invasive species succeed? Invasive species have unique traits Invasive species are released from natural enemies Invasive species are able to capitalize on underutilized resources (empty niche)

20 Do invasive species have unique traits? Plant examples: High fecundity Rapid growth Independence from mutualists

21 Do invasive plants have unique traits? Pysek & Richardson, 2007

22 Do invasive plants have unique traits? Van Kleunen et al. 2010

23 Observation: Invasive plants perform better in their non-native range Non-native Range Native Range Mack et al., 2000

24 Enemy Release Hypothesis Species introduced into a novel habitat are typically introduced without their native predators Release: fewer herbivores are eating me Advantage: non-native plants grow more leaves/roots/flowers and are more competitive, fecund etc. Invasion is more likely to take place.

25 Enemy Release in Plants Study of 473 naturalized plants in the U.S. Points below the 1:1 line have fewer fungal pathogens in their non-native range Therefore, plants have fewer enemies attacking them in their non-native range Mitchell & Power, 2003

26 Enemy Release in Animals Study of parasites in 26 species in their native vs. non-native ranges Fewer parasites in the non-native range Torchin et al., 2003

27 Observation: Some ecosystems seem more susceptible to invasion than others Wilcove et al., 1998

28 Hypothesis: Islands have empty niches Why might islands have under-utilized resources compares to mainlands? vs.

29 Species diversity in a location is a function of colonization (adds species) and extinction (subtracts species) Island Biogeography

30 Colonization is more likely with proximity to mainland (i.e. source of species) Extinction is more likely if the land area (i.e. available niches/resources) is small Island Biogeography

31 Resource usage Island Biogeography Result: Islands have extra resources and therefore empty niches Note: an island could be any hard-to-reach location or young ecosystem Resource supply

32 Humans add extra resources

33 Invasive plants & rising CO 2 Comparisons of invasive vs. native plants favor the invasives Smith et al., 2000 Song et al., 2009

34 Stages of invasion Lockwood et al., 2007

35 Invasive species impacts Population level impacts: Direct predation Competition Community level impacts: Ecosystem chemistry (e.g., nutrient cycling) Ecosystem structure (e.g., height, density) Ecosystem function (e.g., fire, water cycle)

36 Invasive Species are Predators Towns et al., 2006

37 Invasive Species are Competitors Mack et al., 2000

38 Invasive species are ecosystem engineers Invaded Un-invaded Mack et al., 2000 after Vitousek & Walker, 1989

39 New rules to prevent future invasions? Koop et al., 2011

40 Prevention of new invasions

41 Prevention of new invasions Early detection & rapid response (EDRR)

42 Prevention of new invasions iphone & Android apps: What s Invasive! OutSmart invasive species

43 Go through remaining questions from Mack 1. What are the two ways that humans introduce non-native species? How does the pathway of introduction vary by taxonomic group? 3. List and describe two examples of invasive species impacts on native species populations or on ecosystem-level function. 4. List and describe two strategies for the control of invasive species. 5. Describe one other piece of information you thought was interesting in this paper.