Species, vegetation and ecosystems - Lunds...

INVASIVE SPECIES

Why do we have to think about

invasive species

• A new species in the ecosystem should

higher the biodiversity.

• What is wrong on such hypothesis

Species invasion can be seen as predominantly post-Columbian events.

Magnitude of human driven species migration of the last 500 years

(deliberate and accidential)

rivals the changes wrought by continental glaciation cycles.

(Mack et al. 2000)

European trend in aquatic invasions: Seas

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Sources on non-native plants in the UK

Garden Escape

Seed Contaminant

Feral Crop

Landscaping

Aquarium Escape

Medicinal Herb

Forestry

Other

Exotic species: a Scottish perspective

A total of 988 non-indigenous species occur in Scotland

Vascular plants

Molluscs

Birds

Insects

Fish

Mammals

Bryophytes

Amphibia

Over 80% are plants

http://dabrownstein.files.wordpress.com/2013/09/number_of_harmful_alien_species-1.jpg

Number of known harmful invasive marine species on a global view

Invasive: penetrate into a new region, what causes damages.

Invasive species is a species, which is introduced into a an

environment which is spatial different from its original

distribution.

Invasive: causing damages => invasive species are believed to

cause damages in the new ecosystem.

A species which immigrates into a new habitat is NOT by

definition an invasive species.

If the status of damage is uncertain: alien, exotic, neophytes,

nonindigenous....

A species which immigrates into a new habitat is NOT

by definition an invasive species.

Why species immigrate? Inidividuals of species immigrate.

Naturally:

By accident: wind blown, stream / ocean floated, orientation loss

Spatial population expanding by:

adaptation to wider range of environmental conditions

changes of environmental condition to favour species

out side former distribution range

Immigrating means also emigrating of individuals from former habitat

Driven by:

habitat loss:

changes in habitat size,

changes in population density

changes in environmental conditions



Why species immigrate? Inidividuals of species immigrate.

Human impacts:

By accident: transported along human made transportation ways:

trails and track by food, horses, etc.

streets and ways used by cars

highways

ship routs

Species ’tramp’ with transpoted goods and food: globalisation problem

since continental trading.

On purpose: introduction of exotic species

into botanical gardens, private gardens

pets, domestic and farm animals

food



Why species immigrate? Survival of Inidividuals of species.

Naturally:

By accident: wind blown, stream / ocean floated, orientation loss

Spatial population expanding by:

adaptation to wider range of environmental conditions

changes of environmental condition to favour species

out side former distribution range

Immigrating means also emigrating of individuals from former habitat

Driven by:

habitat loss:

changes in habitat size,

changes in population density

changes in environmental conditions

Possibility of species becoming invasive species

Number of contacts with new environment

times and number of individuals

Genetic diversity and mutation rate to adapts to new environment

Success in resource use to compete against native species

Succes in reproduction to outcompete native species in individual

numbers

The processes involved in

invasions

• Barriers

• What makes a species successful

• What makes a habitat or ecosystem

vulnerable

• Impacts

Impacts examples:

• Impacts on community structure – composition & diversity

• Impacts on higher trophic levels e.g consumers and decomposers

• Impacts on nutrient cycling e.g. Nitrogen fixers increase available nitrogen

• Impacts on Hydrology e.g. Changes in ET or runoff

• Impacts on fire regimes – changes in frequency or intensity

Direct damage on biotic environment:

Direct changes in the food web and food web hierarchy

Generalistic predator reduces populations size of certain species until

at least local extinction occurs

Raccoon dog and European singing bird & reptile population

Effects of invasive species to ecosystem

Nyctereutes procyonoides

(Gray, 1834)

native

introduced

Indirect damage on biotic environment:

Direct changes in the food web and food web hierarchy by

competetive effects

Same niche for resource use, but at least slightly higher reproduction

rate reduces succes of native species

American grey squirrel versus European red squirrel


http://images.northrup.org/picture/xl/squirrel/north-

american-grey-squirrel084.jpg https://c1.staticflickr.com/7/6002/5921845600_1ba3

272f04_z.jpg

Direct changes in abiotic environment:

Indirect changes in the food web and food web hierarchy

Primary producer: more efficient use of one resource give ability to

reduce a second resource to change abiotic conditions from micro

scalic to mesoscalic extend.

Precipitation and run-off driven shallow lakes underly changes in

hydrologidal regime by invasion of riparian plant species with high net

primary production and resulting higher transpiration rate.

Results in lower reproduction rate of lake associated natice species.


Ranunculus aquatilis L. Iris pseudacorus



Primary producer: more efficient use of one resource give ability to

change environmental conditions like fire regime.


Invasive species must be adapted to fire

already in its native distribution range

Brooks et al. 2004

Brooks et

al. 2004



Secondary producer: more efficient use of one resource give ability to

change mechanically/chemically abiotic conditions from micro scalic

to mesicalic extend.

Physically damage in topography and stabilty of ground.


muskrat (Ondatra zibethicus)

native introduced

Build nest while burrow into the bank with an

underwater entrance, can cause sometimes enormous

damage to riparian zones and reed beds

http://en.wikipedia.org/wiki/Muskrat






Physically damage via changes in net radiation impact to soil by

different shade intensities of tree species.

Birch via beech


http://ichef.bbci.co.uk/naturelibrary/images/ic/credit/640x395/e/en/engli

sh_lowlands_beech_forests/english_lowlands_beech_forests_1.jpg http://static.panoramio.com/photos/large/13011606.jpg






Chemically changes/damage in environemt.

Cyano bacteria or algea bloom in linological environments (change

from aerobic to an-aerobic conditions)


http://p5.focus.de/img/fotos/crop828278/1732716228-w1200-h627-o-q75-p5/Umwelt-Am-Strand-von-St-Michel-en-Greve-in-der-Bretagne-tuermen-sich-die-Algen.jpg

Indirect changes in abiotic environment:

Direct changes in the food web and food web hierarchy

See before


Alien impacts: non-native flora

Campylopus introflexus

Reduces Calluna regeneration

Rhododendron ponticum

Reduces species richness

Picea sitchensis

Ecosystem change

Hyacinthoides hispanica

Hybridization with natives

Ambrosia trifida

Health risk

Oxalis pes caprae

Economic damage

Alien impacts: non-native fauna

Arthurdendyus triangulatus

Earthworm predator

Arion lusitanicus

Economic damage

Cervus nippon

Hybridization with natives Wildfowl predator

Sciurus carolinensis

Wildlife disease

Branta canadensis

Social and economic pest

http://homepage.ntlworld.com/nicholas.forrest/canada geese 1 o.jpg

Three steps to invasion

Species

introduced

Species

naturalised

Esta

blis

hm

ent

Species

spread &

invasion

Epidemiology of invasion

Multistage process

transport, migration, immigration from origin source to new

locals

overcome ’distance’ barriers survival of individuals

overcome physical and biotic stresses

establishment of population

overcome competetive stresses and environmental

unsuitabilities

naturalized in new environment

independent from new ’recruits’ arrival from source

population

adaptation to new environment

invading new environment

spread through new environment by population increase

and dispersal and have an measurable impact on the

ecosystem

Mack et al. 2000

Understanding pathways: entry routes

How many routes lead to species introductions?

Contaminants of agricultural & aquacultural produce

Contaminants of commercial grain supplies

Seed contaminants of nursery & cut flower trade

Organisms on timber

Seed contaminants of soil

Machinery, equipment, vehicles, aircraft

Contaminants of packing materials

Contaminants of mail and cargo

Ballast soil

Ballast water

Hull fouling

Tourists and their luggage

Other

Humans as dispersal vectors

Accidental:

globalisation in transport


Accidental:


The brown tree snake

(Boiga irregularis)

responsible for

devastating the majority

of the native bird

population in

http://en.wikipedia.org/wiki/Brown_tree_snake

Guam

http://en.wikipedia.org/wiki/Guam

http://ec.europa.eu/environment/marine/images/picture-descriptor2-

indigenous-species.png


Accidental:



Accidental:

ancient human migration

http://www.utexas.edu/features/2007/ancestry/graphics/ancestry5_medium.jpg


Accidental:

ancient human migration

http://www.utexas.edu/features/2007/ancestry/graphics/ancestry5_medium.jpg

Invasion of

live stock with

parsites and diseases,

human co-eolved

parsites and diseases


Accidental:

tourists

Alien Invaders Hitchhiking to

Antarctica

http://news.discovery.com/earth/plants/invasives-across-antarctica-

120305.htm

Poa annua Annual bluegrass


Accidental:

tourists


deliberate:

botanical garden escape

Impatiens parviflora (Small Balsam or Small-

flowered Touch-me-not)

http://de.wikipedia.org/wiki/Kleines_Springkraut

European vegetation development

since the last glacial maximum Huntley (1990)

Distribution of ”vegetation units” based on pollen data

Natural migration

Range shift by climate change in the past

Trachycarpus fortunei (Hook.) Wendl.

Palms a bioindicator of

warm and humid climates

Walther et al. 2007, Palms

tracking climate change, Global

Ecology & Biogeography

Natural migration

Range shift by climate change current

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Trachycarpus fortunei (T.f.) widely planted in garden and parks

T. f. seeds freely in protected sites

Small palms in herb layer

T. f. palms in shrub layer

Reproducing T. f. palm population

Stages of invasion process

y = 0,0127x + 1,3932

R2 = 0,1374

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Local climate data vs invasion history in southern Switzerland.

Milder winters (days without frost)

50 years ago colonised protected sites, 20 years ago palm seedlings in

forest stands and persisted in face of competition leading to fully

functioning populations

Natural migration

Range shift by climate change in the future

Simulated present and potential future ranges

of Locustella naevia.

(a) Simulated distribution of Locustella naevia

(Grasshopper Warbler) in Europe for the

‘present’ (1961–90) climate. Blue symbols

represent grid squares simulated as suitable,

yellow symbols grid squares simulated as

unsuitable.

(b) Simulated potential distribution of

Locustella naevia in Europe for the HadCM3

B2 future climate scenario (2070–99).

Potential Impacts of Climatic Change on

European Breeding Birds

Brian Huntley et al. 2008


Multistage process

transport, migration, immigration from origin source to new locals

overcome ’distance’ barriers

survival of individuals



overcome competetive stresses and

environmental unsuitabilities naturalized in new environment

independent from new ’recruits’ arrival from source

population





ecosystem

Mack et al. 2000

What makes a species successful

The transformation process from an immigrant to

an invader

LAG LOG


an invader

Lag phase: time span often uncertain:

European beech time lag up to 2000 years after LGM

African bees, time span for lag phase almost not recognisable

A species immigrating into a new area could always transform from

an immigrating into an invasive species.

Every immigrating species is a risk for the ecosystem!

Population size

time


an invader

Lag phase: hypotheses of its occurring

1) Limits on detecting of small population’s growth

2) Limitation in number and arragements of sub-population occurring as

one meta population.

3) Natural selection among rare/newly created genotypes in new

environments (bottleneck hypothesis for immigrating species)

4) Vagaries / stochastic occurrences of environmental dynamics (small

population rather affected by environmental dynamics than

established populations

If certain population size is reached, threshold for population

size to be defined as established, species could transform into

an invasive species, log phase occurs.

Dlugosch & Parker 2008: genetic bottleneck in invasive species

Literature

study of 80

species

Proportional changes in allelic richness by the year since introduction is known


Multistage process







environmental unsuitabilities


independent from new ’recruits’ arrival from

source population

adaptation to new environment invading new environment



ecosystem

Mack et al. 2000

What makes a species successful


an invader

Log phase:

- Species is adapted to biotic and a-biotic environment

- Species developed high competetive strategies among native species

- Species developed higher reproduction rate than competing native species

Bradley et al.2006: Invasive grass reduces

aboveground carbon stocks in shrublands of

Western US. GCB 12, 1815-1822

Ecosystem conversion has changed parts of the western US from a carbon sink to a

source. The increasing importance of invasive species in driving land cover changes

may substantially change future estimates of US terrestrial carbon storage

Non-native annual

grass (cheatgrass)

promoted by

disturbance e.g. fires

and competition

Widespread neophyte plants in Europe

Phytolacca americana

http://www.europe-aliens.org

Carpobrotus edulis Conyza canadensis

Canadian fleabane Hottentot fig

American pokeweed


Multistage process







environmental unsuitabilities


independent from new ’recruits’ arrival from

source population



spread through new environment by

population increase and dispersal and have an

measurable impact on the ecosystem Mack et al. 2000

What makes the environment vulnerable

Invasive plant

Introduced in Europe in late 19th century as an ornamental

Displaces local vegetation, roots disturb foundations and flood defences,

Reproduces clonaly via rhizomes, majority of plants are female

In the UK, all plants belong to the same clone which also occurs in Europe

http://upload.wikimedia.org/wikipedia/commons/2/23/Riesenknoeterich.jpg http://www.europe-aliens.org/images/factsheetMaps/9_faljap.jpg

Fallopia japonica: Japanese knotweed,

Scale of impacts on species richness

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Native

Alien

Plant invasion of Mediterranean islands

Source of aliens in Mediterranean islands

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Diversity and ecological equivalence

Aliens functionally different from natives

Agavaceae Simaroubaceae Nelumbonaceae

Cactaceae Phytolaccaceae Mimosaceae

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Growth-form (Raunkiaer)

Ant supercolony = super alien colonist

Introduced in Europe in 1920s on imported plants

Spread throughout much of western Mediterranean

Displaces local arthropod fauna, protects pest insects and destroys fruits

Largest supercolony ever recorded, stretches 6000km

Advantages of supercolony: high worker densities, interspecific dominance

100km

Argentine ant (Linepithema humile)

Zebra mussel crossing Europe

First mass invasion of a Ponto-Caspian species

Moved through canal and river networks on barges and boats

Can survive out of water for >2 weeks so spread by boats on trailers

Transforms eutrophic freshwaters via filter feeding resulting in loss of fish

Blocks drains of power and waste systems of power plants

Zebra mussel (Dreissena polymorpha)

Rhododendron ponticum

Glen Etive, Argyll

Rhododendron

introduced 1910

Subsequent

extensive spread

in moorland

along waterways

Exported trouble: the US experience

Ivy Gorse Garlic Mustard

Stewart Island New Zealand – invaded dune system

Exported to New Zealand

A nature rear dune being invaded by European Marram grass

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Barriers limiting

introduced plants Richardson et al. 2000

Diversity & Distributions 6,

93-107

Barriers - Introductions

• Major geographical (intercontinental) >100km

(human involvement) – Introduction

• Introduced taxa may survive as casuals – can

reproduce but fail to maintain populations over

long periods.

• Casuals rely on repeated introductions

• Environmental barriers (abiotic or biotic) at site of

introduction

Barriers - Naturalization

• Naturalization occurs when

– Environmental barriers do not prevent

individuals surviving

– Barriers to reproduction are overcome

– Naturalised after Barriers A, B, C overcome

– Populations large enough so that the probability

of extinction due to chance events is low

Barriers – Invasion (1)

• Invasion – spread away from sites of

introduction

• Overcomes barriers to dispersal (D) and

barriers in the abiotic and biotic in the area

(E)

• Invade disturbed semi-natural habitats

Barriers – Invasion (2)

• – Invasion into mature undisturbed communities (F)

• Can be aided by for example mutualism – symbionts or mutualistic partners

– Generalistic pollinators

– Generalistic fruit eating species

– Generalistic mycorrhizas

– Nitrogen fixers

What makes a species successful ?

• Weedy e.g.

– ability to reproduce sexually and asexually

– Rapid growth from seedling to maturity

– Adaptation to environmental stress

– Tolerant of environmental heterogenity

What makes a species successful ?

• Plant growth form and habitat

characteristics

– Plant height

– Life form

– Competitiveness

• Broad ecological amplitude

(light/humidity)

What makes a community or ecosystem

invasible or not ?

• Abiotic conditions (e.g. light, temperature)

• Biotic conditions (e.g herbivory)

• Soil resources e.g. nitrogen availability

• Ecosystem stability?

http://blogs.oregonstate.edu/wise/2014/03/13/lionfishs-roaring-impacts-atlantic-ocean-fish-populations/

Lion fish (Pterois volitans) in Atlantic Ocean. Native to Indo-Pacific Ocean,

first found in Atlantic in 1980′s

Probably released by exotic fish aquarium owners off the coast of Florida;

carried northeast to North Carolina and Bermuda by gulf stream current as eggs

or larvae.

Food: anything smaller than them self: fish, shrimp, crabs and octopus.

no natural predator, Start hunt lionfish for food: biomass removal

Interactions Relationship between invader and invaded ecosystem

Dukes & Mooney 1999 – Does

global change increase the success

of biological invaders

TREE 14, 135-139

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