invasive species

Articles in ‘invasive species’

Asian predatory wasp in Spain

November 5th, 2013

Beekeepers and fruit orchard growers in Spain are facing the serious threat of Asian predatory wasp (vespa velutina nigritorax), which has spread from France. The species was first detected in the Basque Country three years ago from where it has spread to Castilla y León, Cantabria, Asturias and Galicia . In 2013 it was found in La Garrotxa (Girona) in Catalonia having spread from a separate French population. Honeybees make up some 80’% of the wasps diet. Even more worryingly, the wasps also pose a considerable risk to biodiversity in Spain as  many plants are dependent on honeybees for pollination. As far as humans are concerned, people have been hospitalised in France after suffering anaphylactic shock as a result of multiple stings.

More here from El País

Hundreds of specimens of Vespa velutina, a species of hornet known popularly as “the Asian predatory wasp” or “the Asian hornet,” were found last month in the Vall d’en Bas, a valley in the Catalan municipality of La Garrotxa. The find has sent all kinds of alarms ringing among rural officials and local beekeepers, who know time is running out: if the nest is not found and destroyed by November, the females growing within will fly out and start their own colonies elsewhere in the region.

“Before the fall is out, the more than 200 wasp mothers now germinating inside the nest will seek new locations to create new hideouts and hibernate,” explains Josep Vilar, chief of the rural agents of La Garrotxa. Each female can produce over 12,000 offspring.

Tiger mosquitoes in Barcelona

July 22nd, 2013

tiger mosquito hostsInteresting chart comparing the dining preferences in Barcelona of native mosquitoes with the dreaded Tiger Mosquito, an invasive species from Southeast Asia. While the former’s victims are: 35.7% humans, 21.4% cats, 14.3% dogs, 8.5% Turkish dove and 19.1 % other birds (pigeons, parakeets and blackbirds, sparrows etc), the Tiger Mosquito feeds EXCLUSIVELY on humans, which it bites during the day. My own resistance has built up remarkably over the last eight years since they arrived, and although their bite is still a burning one, the swelling now goes down after about 30 minutes

Raccoons in Madrid

July 22nd, 2013

The Madrid goverment is to attempt to eradicate the region’s 300-strong population of raccoons, which has mushroomed from a small number of escaped or released unwanted pets. More in El País here.

Invasive species in Mallorca

November 26th, 2009 The biodiversity of Mallorca is threatened by invasive species. Exotic pets released by bored owners are a serious issue, including a breeding population of coatis in the Sierra de la Tramontana. El Mundo More on the Mallorcan coatis here

Tiger mosquito reaches Girona

September 3rd, 2008

The tiger mosquito continues its slow and seemingly unstoppable march, and has now reached Roses and L’Escala in Girona according to the Servicio de Control de Mosquitos de la Bahía de Roses y el del Baix Ter. La Vanguardia

Tiger mosquito continues to expand

June 29th, 2008

The tiger mosquito continues to expand in Catalonia, doubling its area of distribution between 2006 and 2007, and now present in 55 municipalities including Barcelona. El Periodico

See also arrival of tiger mosquito to Spain (2005)

Beaver erradication begins

May 12th, 2008

The plan to eradicate (or at least control) the population of beavers, illegally introduced into the River Ebro several years ago, has begun with the live capture of three animals. La Rioja.com
See also Beavers in Spain (Iberianature)

Beavers in Spain – Castores en España 2

December 8th, 2007

Following on from the Beavers in Spain news, European beaver expert Dr Duncan Halley of the Norsk Institutt for Naturforskning has very kindly written this facinating piece for Iberianature on the Navarran beavers.

“The reasoning of the Spanish authorities, that allowing illegal reintroductions to take place sets a bad precedent, is quite understandable. Conservationists often complain when others take the law into their own hands, e.g. by illegal shooting of protected species; the same principle applies here.

In 2005 I was contacted by scientists working for the Navarrese regional government, who sent some pictures of unmistakable beaver signs they had come across while working on European mink. I later visited the site, and saw from a video that the animals are definitely breeding. The exact site I saw was the most favourable for beavers I think I have ever seen, oxbows off a main river with thick, shrubby growth of poplars (easily the beaver’s favourite tree genus), and lots of herbaceous growth as well. Combined with the very benign climate and the very large amount of suitable habitat available on the Ebro system, I have no doubt the species, left to itself, will become firmly established. Unmanaged the river system could support a large population, probably over a thousand individuals. After at least four breeding seasons, the population, allowing for natural increase, is probably well in excess of 50.

As regards the technical aspects of a removal effort, it’s worth recalling how extinction occurred. Beavers were hugely reduced in numbers in most places by mediaeval times, but in most of Europe, including Spain, small populations hung on for well over 500 years until the 17th-19th centuries, the 17th century seeing the arrival of accurate firearms and efficient steel traps. These last beavers tended to be in the best beaver habitat, marshes or large rivers with plenty of cover and no need to dam, or even fell trees much; beavers were therefore hard to find there. The conditions for final extinction also included the very high value of beaver fur combined with the value of the castoreum gland (medicine, perfume), literally worth more than its weight in gold. One beaver was worth more than a Norwegian farmhand’s annual wage in the 18th century, to give perspective. Every man’s hand was turned against them, and by the C17th most people could get hold of a gun or a trap if a beaver was noticed.

Under modern conditions, to remove beavers from a watershed as large as the Ebro requires a professional effort, as the animals no longer have significant commercial value (except for sport hunting in some places). In the case of the Ebro, there are two factors further complicating a removal effort. At low populations beavers typically select strongly the very best habitat patches, living in burrows and felling few trees; in areas with much bushy growth by the waterside, nothing larger than twigs. This will make finding all the sites difficult in a big river system with so much suitable habitat. Interpretation of signs can also be problematic: are they caused by an established family or just a passer by? All this takes time, and so money. Secondly, at least four breeding seasons have occurred since reintroduction. At low population densities, beavers disperse as yearlings and very much evidence shows they will travel long distances – many cases of over 50km are known – to find the very best habitat rather than settle close to their natal territory.

It seems the trapping will be carried out in La Rioja and Navarra only; however, the Ebro runs into Aragon just downstream from the known reintroduction area, the north bank is in the Basque Country not far above it, and the river runs on into Castile y Leon another 20km or so upstream. All these are well within the recorded dispersal distance of beavers in unsaturated habitats, and it is highly probable that some beavers are established there by now. A trapping effort confined to Navarra and La Rioja with therefore probably leave breeding groups both up- and downstream, from which young animals can redisperse into those provinces.

It appears that live trapping will be the preferred method. There are two effective methods, dazzle netting using a trained trapping crew operating at night, effective but expensive given the manpower requirements; or Hancock traps, which are set partly in the water on the riverbank, and baited with territorial scent or poplar twigs. When triggered, they scoop the animal up from below so that it ends up sitting in a basket above water level.

To summarise, an effective removal is technically feasible. However, it will have to carefully check many tens of km of riverbank for beaver signs, a considerable way up and downstream from the known reintroduction area, including stretches beyond Navarra and La Rioja, determine where the settled groups are, and trap them all. The Ebro is a particularly difficult river system for the purpose, being so large and containing so much good habitat; the resources put into the effort would have to be commensurate with this. If the effort is confined to Navarra and La Rioja, the prospects of complete success depend on whether beavers are established elsewhere on the river. Given their known behaviour and the local political geography, this must be regarded as highly probable.”

By Dr Duncan Halley, Norsk Institutt for Naturforskning

Alligator caught in River Besòs

September 26th, 2007

A young alligator (70 cm) was caught in Barcelona in the River Besòs yesterday. The reptile was spotted by a local naturalist doing a study on birds. Experts believe the mild temperatures on the Catalan coast and the abundant presence of swamp crayfish may allow alligators to survive the winter here.  This is the second alligator to be caught in just over a year near Barcelona, after the larger alligator caught in a pool in Collserola. (El Pais)

Barcelona’s parakeets to be culled

July 22nd, 2007

I received this email this morning. It’s based on this article http://www.20minutos.es/noticia/260758/0/autorizan/caza/cotorras/ . Although I have grown to love this pesky fellows I myself have no intention of signing this petition as potentially monk parakeets could cause big problems in the surrounding countryside to farming and wildlife. I hope they are only going to reduce numbers. If you don’t agree with me, please sign their petition. More on monks here: http://www.iberianature.com/material/barcelona_birds.html

“Dear Mr Lloyd,
A contact e-mailed me yesterday about the planned wild parrot hunt in Barcelona. I am based in Brooklyn and the monk parakeets live here peacefully with other wildlife. I am shocked and discouraged by this planned action and am organizing a protest. But there is not much I can do on this side of the Atlantic. What’s needed are voices in Spain that are against it.
I have written about this issue and have an online petition. If you could spread the word in Europe, I’d be grateful”
Full story here:

http://www.brooklynparrots.com/2007/07/very-bad-news-from-spain.html

Thanks,
Steve Baldwin
The Brooklyn Parrot Society