The Segura River basin closes its doors to the ‘invaders’
ECONEX NEWS
OUR LAND/ LA VERDAD NEWSPAPER, MURCIA
3.02.15 – MIGUEL ÁNGEL MUÑOZ
The Segura River basin closes its doors to the ‘invaders’
Experts from all over the country have come to Murcia to discuss how to protect the riparian forest and its ecosystem from present and emerging exotic species
FIGHTING AGAINST THE PESTS
Invasive exotic species are the various ecosystems unwelcome guests. They are one of the main reasons for the world’s loss of biodiversity and cause serious damage to the economy, especially in agriculture, livestock farming and forestry.
The problem is that to eradicate or keep these ‘intruders’ at bay once they have already adapted to the environment, is on many occasions an impossible undertaking. Although their early detection together with the availability of extensive research about the different species and plans of action, are tools that can help to quickly intervene and put a stop to their expansion and the damage they cause.
The waters of the Segura River and its riverbanks are an ecosystem where exotic species – with fishes such as Alburnum, Rainbow Trout, Black Bass, Pike and Perch; crustaceans like the American Crab and reptiles such as the Giant Tortoises ‘Trachemys scripta scripta’, Trachemys scripta elegans’ and ‘Graptemys pseudogeografica’ – have settled and in many cases want to occupy the natives’ space, who they have hanging by a thread (rivalry, eviction or they are predators); given that the natives have evolved without any specific adaptation to fight against these settlers.
At the Chamber of Commerce in Murcia last week, the Segura River Basin Authority organised a conference titled ‘Invasive Exotic Species in the Riparian Habitat’. It is a topic in which the Segura River Basin Authority sought, amongst other issues, to publish its ‘Life+ Ripisilvanatura’ project, in which the ANSE (Asociación de Naturalistas Del Sureste), the University of Murcia, the Murcian Regional Government and the Town Councils of Cieza and Calasparra also collaborate.
Ripisilvanatura’s intention is to restore the riparian forest in the middle watercourse of the Segura River, on a section of river that includes the towns of Moratalla, Calasparra and Cieza, through the control of invasive exotic plants (those that are outside their native distribution range and have a negative effect on the local ecosystem). They can be found mainly in Willow and Black Poplar forests by the river and are listed as ‘top priority’. The project, which will continue until September 2019 has a budget of 2.454.611 euros, half of which is funded by the European Union. The various tasks to be carried out will cover 51 kilometres of the river.
Beating the reeds
The conference brought together representatives from universities, water authorities, environmental organisations, local governments and research centres to share their experiences on the fight against different exotic species. One of the species mentioned is the Giant Reed (‘Arundo donax’), the main enemy of the riparian forest on the Segura riverbed. The environmental consequences of its colonisation are the increased risk of forest fires and the loss of biodiversity, as well as creating an obstacle for the flow of water if there is flooding.
The reed is an invasive species with the greatest presence in the scope of the Ripisilvanatura project and a large percentage of the budget has been allocated to fight against it. Therefore, they will prune the reeds manually and proceed to break up the most concentrated areas of ‘Arundo donax’, like many other invasive species such as: Cat’s Claw (‘Carpobrotus edulis’), St. Augustine grass (‘Stenotaphrum secundatum’), Pampas grass (Cortaderia selloana) and Japanese honeysuckle (‘Lonicera japonica’). At the same time the project will carry out reforestation work with native plant species who are acclimatised to hot temperatures and droughts.
They also examined other foreign species living in the Murcian Region, such as the Red palm weevil (‘Rhyncophorus ferrugineus’) and the Asian clam (‘Corbicula fluminea’). Diego Gallego, from the company Econex, gave a presentation on the Red palm weevil. It is a beetle, native of Tropical Asia that mainly affects the Canary Island Date Palm (‘Phoenix canariensis’), Date palm trees (‘Phoenix dactylifera’) and Washingtonia (Fan) palm trees (‘Washingtonia spp.’).
This beetle lays dozens of eggs at the base of the leaves that then hatch and develop into larvae, measuring between 4 and 6 centimetres long. They enter via the main shoots of the leaves, destroying the growth of the plant and causing its death. In species such as the Date palm tree, it can also cause it to decline. This pest first appeared in Spain in 1994, Almuñécar (Granada). Its origin is the result of infected palm trees imported from Egypt and other North African countries. Although, it wasn’t until 2004 that alarm bells started ringing, after discovering the first set of serious damages in the Valencian Community.
The Red palm weevil’s dispersion rate throughout the Mediterranean has been relentless, given that the extermination measures already in place have proved to be ineffective up to now and have not served to contain them. They have spread all over Europe and reached the United States and Saudi Arabia. The first important moment it appeared in the Murcian Region was in 2005. In percentages, it mainly affects Canary Island palm trees (82%), followed by Date palm trees (17%) and on a smaller scale Washingtonia (Fan) palm trees and others (1%).
Jaime Fraile, Coordinator of the Ripisilvanatura project and Head of the Water Planning Department at CHS (Segura River Basin Authority), explained that the inclusion of the Red palm weevil in the conference talks programme was because it is a species that has «aroused much concern in the Segura River basin». Despite the palm trees not being native of the riverbank, in the past they were used in certain areas along the river for decorative purposes. But they had to get rid of them because of the damage caused by the beetles.
A question of money
During his conference, he highlighted that the invasive exotic species are a problem <
«Even with these tools, nobody guarantees us that we will be able to eradicate a species that has already settled, nor can we stop other species from arriving. Although, we will advance a great distance in the right direction», he commented. Thus, one of the plans of action in Ripisilvanatura is the creation of a Land Preservation Network to get both landowners and land users involved in the preservation and good use of the riverside forest. There will also be training «to stop freeing exotic species through lack of knowledge» added Adolfo Mérida, who is also project coordinator and Dam Maintenance Manager at CHS. He emphasised the necessity to improve organisation between the different local governments and establish specific protocols against the invasive exotic species.
The invasive clams
The Asian clam, is native to Southern Asia and the most recent newcomer to the Segura River (2013). Its presence for now is limited to the Vega Baja area. The main threat from this clam is its great capacity to filter water, reducing the amount of food on the surface layer of the sediment, which prevents other species from being able to feed themselves. They also obstruct the pipes and water inlets, affecting agriculture and industries.
Ramón M. Álvarez and Antoni Javierre from the University of Zaragoza, put forth a number of suggestions to improve the management of this species in the basin of the Segura River. For example, conducting periodic tests by way of a general inspection on the quality of the ecosystem, as well as, studying the presence of possible ecological impacts of the species and decide its level of dispersion or regression. They also recommended building disinfection stations, at least one every 100 kilometres along the riverbed and offered environmental education on the native species that need protecting and control the invasive exotic species.
Javierre bemoaned the «lack of interest» from local governments and the public concerning the Asian clam. The reason, in his opinion, is that it is a species that does not cause such serious problems to the infrastructures as the Zebra mussel, nor does it produce such a negative impact on agriculture as the Apple snail. Javierre pointed out that the Asian clam can already be found settled in 80% of the Iberian Peninsula and that the United States is the country doing the most to fight against it. On the other hand, he said that communication is key between water authorities «to evaluate at which stage of invasion they find one another and anticipate courses of action».
In addition to the measures taken to carry out controls, the researcher highlighted mechanical methods such as anoxia barriers that reduce the levels of dissolved oxygen in water, eliminating the population levels in just a few weeks. In regards to the pipelines, Javierre explained that the most effective technique is to raise the temperature of the water to 35⁰C, which kills the larvae and the young.
