Historical disasters

In this work we will talk about three different types of plants and one animal in Portugal.

Our goal is to give you some information about their characteristics and important facts .

I hope you like it !

Mimosas

Evergreen tree, with grey-green bipinnate leaves and bright yellow spherical flower heads.

Characteristics that aid invasion:

It propagates vegetatively, forming vigorous sprouts from the stump or roots after being felled.It also reproduces by seed, producing many seeds that accumulate in numerous seed banks and remain viable in the ground for many years. The seeds are dispersed by animals, mainly birds and ants, and sometimes by strong winds which lead to the formation of dispersed and/or far away invasion foci from the invaded areas. Most propagules, however, accumulate underneath the tree, forming a numerous seed bank. It germinates aggressively after fires.

Native distribution area: Southeast Australian states of New South Wales, Victoria and Tasmania. Distribution in Portugal: Mainland Portugal (all provinces), Madeira archipelago (island of Madeira). Jacintos de água

Aquática herb, floating, with swollen leaves and very flashy blue/violet flowers.

Characteristics that aid invasion:

Eichhornia crassipes has an extremely rapid growth: in adequate conditions, the species may double its population in 5 days. The growth rate is higher in springtime, reducing in autumn due the decrease in temperature and formation of frost. It may survive on land if there is a large amount of water available.

It may easily propagate vegetatively, through rhizomes or small fragments from which a new plant may generate. Each fragment may be dragged by the water flow and originate new invasion foci far from the original population.It also propagates by seed. The seeds can be viable for a long time (up to 20 years) and due to their small size, they are easily swept up by the current. The seeds are also dispersed by aquatic birds.

Native distribution area:South America, in the Amazon Basin.

Distribution in Portugal:Mainland Portugal (Douro Litoral, Beira Litoral, Estremadura, Ribatejo, Alto Alentejo), Azores archipelago (islands of Flores, Faial, Graciosa, Terceira and São Miguel). Eucalipto

Evergreen tree, aromatic, with young bluish-green leav

In Portugal, the most area occupied by this species corresponds to plantations by Man and not natural dispersal/invasion. The species is included as invasive because, on one hand, it has seen its invasive behaviour in many situations in the country and, on the other hand, its wide distribution creates a high propagule pressure which constitutes an increased risk. Additionally, this species is considered invasive in many regions with Mediterranean type-climate.

Characteristics that aid invasion

Species of very fast growth. It propagates vegetatively, sprouting vigorously from stumps (used in the pulp industry). In Portugal, for a few years now, seed germination has started to be observed, including outside the stands, mainly after the plantation abandonment and wildfire occurrence, which create empty niches.

Native distribution area

Southeast Australia and Tasmania.

Distribution in Portugal

Mainland Portugal (all provinces), Azores archipelago (islands of São Miguel, Santa Maria, Terceira, Graciosa, Pico, Faial and Flores), Madeira archipelago (Madeira and Porto Santo islands).

Háquea-picante

Evergreen shrub or small tree, with robust and very sharpneedle-like leaves.

Characteristics that aid invasion:

It reproduces by seed. Frequently, the seeds remains enclosed within the fruits, which in their turn remain grasped to the tree, throughout the plants’ lifetime. They are released when the tree is burned or dies. The seeds are then projected to great distances, creating new invasion foci that frequently occupy very extensive areas.

Native distribution area:

Southern Australia.

Distribution in Portugal:

Mainland Portugal (Trás-os-Montes, Minho, Douro Litoral, Beira Baixa, Beira Litoral, Estremadura, Ribatejo, Baixo Alentejo, Algarve.

Lagostim vermelho

It is a freshwater crustacean that has a reddish or brownish color. It has five legs, breathes through gills and can remain some time out of water.

Characteristics that aid invasion:

Louisiana red snapper causes serious negative impacts on animal and plant life in the habitats it invades and quickly becomes the main species. It fiercely competes with habitat, food and predation with native species of crayfish (in Portugal with Austropotamobius pallipes or white-footed crayfish), contributes to the reduction of macrophytes, invertebrates, amphibians and fish and causes changes in the food chain of habitats Aquatic In short, it reduces habitat biodiversity. Due to excavation, it causes changes in hydrology and soils, including loss of water in rice paddies, reservoirs, etc., with negative implications for the crops produced.

DISTRIBUTION :This exotic and invasive species is native to North America. It is present in several European countries, including Portugal, but also in Africa, Asia and South America.In Portugal it is found in all hydrographic basins

Conclusion:„ In mainland Portugal, over the last two centuries, and especially in more recent decades, the number of exotic species (including causal, naturalized and invasive) has increased significantly, currently amounting to about 670 species*, which corresponds to approximately 18% of the total native flora (Almeida and Freitas 2012). In the archipelagos of Madeira and the Azores the number of exotic species is also very high. For the Madeira and Savage Island archipelagos 430 exotic species have been recorded, equivalent to approximately 43% of all the vascular plants in these archipeligos (Jardim and Sequeira 2008). In the Azores, of the approximately 1000 species of vascular plants, around 60% are exotic (Scott and Smith 2006). We were able to understand and learn some facts about some species , including their origin and present location in the national territory