Biological Invasion

Question 1

Invasive alien species (IAS)

Answer 1

„Invasive alien species: an alien species whose establishment and spread threaten ecosystems, habitats or species with economic or environmental harm“ (IUCN 2001)

IAS are

• of ecological significance (threaten biodiversity, „environmental weeds“)
• of economic significance (yield loss, weeds, pest organisms)

Question 2

Reasons for species loss

Answer 2

Habitat fragmentation, invasive species, pollution, urbanization

Question 3

Archeophytes

Answer 3

Exotic species introduced before 1492. Neophytes: introduces after 1492.

Question 4

invasive vs. alien

Answer 4

Invasive species make only a small proportion of all naturalized alien species in a region.
Alien/exotic plants grow in the wild but were originally introduced by man. They do not cause species loss.

Question 5

Vectors and pathways of introductions

Answer 5

Intentional introduction
Accidental introduction
* Weed seeds as contaminants of cereals, wool, packing materials * Seeds or vegetative parts in soil of pot plants * Seeds in the fur of animals, cloths * Seeds on car tires and agricultural machine

Question 6

Do invasive species share certain traits? Which habitats are prone to invasion?

Answer 6

Habitat properties: no general rules, but disturbances often facilitate the establishment of invasive species

Species properties: no general rules (no key traits), but often observed:
* fast growth, high competitive ability
* clonal growth and vegetative spread
* broad ecological tolerance
* absence of natural enemies
* high seed output

Question 7

What do invasive plant species do? Ecological impacts

Answer 7

They can …
* change ecosystem functions (water and nutrient cycling)
* change natural disturbance regimes (fire, insect outbreaks)
* promote soil erosion
* outcompete native species
* change food web structures
* slow down natural successions
* change vegetation structures
* degrade wildlife habitat
* displace species rich plant communities with monocultures
… often in combination

Question 8

Transformer species

Answer 8

Invasive species, whose impacts affect whole ecosystems at several trophic levels: species richness, vegetation and food web structure, abiotic conditions

Question 9

invasibility def.

Answer 9

how prone a habitat is to become invaded -> property of habitat

Question 10

invasivness def.

Answer 10

how prone a species is to invade a habitat -> properties of species

Question 11

properties of habitat to be prone to be invaded

Answer 11

o High disturbance
o Fragmented habitats
o Altered Hydrology: Changes in water flow patterns
o Excessive nutrient inputs
o Habitats lacking natural predators, parasites, or diseases
o Lack of Biotic Resistance
o Human activities, such as urbanization, land use changes, and global trade

Question 12

Traits of species that make a species prone to invade

Answer 12

o high Reproductive Capacity
o Rapid Growth and Life Cycle
o Wide Environmental Tolerance
o generalist Diet or Resource Use
o High Dispersal Capability
o Allelopathy or Competitive Ability to
escape from Natural Predators or Diseases

Question 13

global lange ecology def.

Answer 13

a scientific discipline focused on studying how human-induced environmental changes, such as climate change and habitat destruction, impact ecosystems and their components.
It aims to understand these effects to inform conservation strategies and mitigate the negative consequences of global environmental transformations.

Question 14

nature based solution for biodiversity loss

Answer 14

ature-based solutions for biodiversity loss refer to strategies and approaches that utilize and restore natural ecosystems to address the decline in biodiversity. These solutions involve activities such as habitat restoration, reforestation, protected area establishment, and promoting sustainable land and water management practices, all aimed at conserving and enhancing biodiversity while also providing benefits for human well-being.

Question 15

Main drivers of biodiversity loss

Answer 15

*Climate change
*CO2 concentration
*Land-use change
*Invasive alien species
*Pollution
*Rsource extraction
*Costal development

Question 16

Invasive species def.

Answer 16

Invasive species refer to non-native organisms that are introduced into ecosystems outside their natural range and have the potential to cause harm to the environment, economy, or human health. They often exhibit aggressive growth and reproduction, outcompete native species for resources, disrupt ecological processes, and can lead to the decline or extinction of native species.