The Conference on Invasive Alien Species held last week as part of the 50th anniversary of the Timanfaya National Park, managed by the Ministry of Ecological Transition and Energy of the Canary Islands Government, had a special remembrance for the Lanzarote biologist Domingo Concepción, recently deceased and one of the first scientists to carry out field work in the park.
The biologist and environmentalist María Bernardos recalled that the calcosa or vinagrera (Rumex lunaria) present in Lanzarote is a native Canary species translocated that was imported from El Hierro in the 30s of the last century for forage purposes and that altered the natural ecosystem of Timanfaya. The plant is not natural to this lava ecosystem and represents a serious landscape impact.
Bernardos has analyzed 30 kilometers of roads and tracks, detecting "six invasive species" on the margins of those most exposed to tourist visits. "It is a fairly small number and we can say that the management of the park is effective," she said. She also warned that "roads fragment habitats and are the main vectors of dispersion of introduced species." It is "essential", the experts agreed, "to maintain the native flora on the edges of the roads and not eliminate it" to prevent the spread of invasive species.
Raimundo Cabrera, professor of Phytopathology at the University of La Laguna, studies possible methods of biological control for the calcosa: a mycoherbicide composed of a local fungus, present in Timanfaya, could inhibit the germination of the calcosa without affecting other species. Two years ago, the Integrated Pest and Disease Control of Vegetables (CIPEV) group of the ULL found the most promising pathogen: the fungus Septoria sp.
"We need to know if it is one species or several, how it is distributed and what potential it has as a mycoherbicide," said Cabrera. This biological control tool should be incorporated into an "integrated management system" that also includes mechanical methods such as manual removal of the calcosas.
The biologist Rafa Paredes, director of the company Gabinete de Estudios Ambientales, coordinates the actions to control the calcosa in the Lanzarote park. "It is one of the few cases in which we know how the colonization process has been," he explained, making a chronology from the first detection of specimens in the 80s to today.
The calcosa is present in 60% of the surface of Timanfaya and 18% of the park requires "priority actions". Thanks to the continuity of the control work, executed from the Ministry of Ecological Transition and Energy of the Government of the Canary Islands, it has been eliminated from the Route of the Volcanoes, with the exception of the slopes, which involve complex vertical work. A video showed the costly and delicate restoration work carried out by the crews.
3,000 citizens collaborate with RedEXOS
The Canary Islands Early Warning Network for Invasive Alien Species "is one of the greatest achievements of the Canary Islands administration," the scientists said. RedEXOS acts only in an initial phase, when the species has not yet spread. Its mobile application is the most important tool, as it allows citizens to send georeferenced reports. More than three thousand users have reported almost 800 taxa (cylindrical cacti, burladoras, cat's tail, Moorish squirrel, sun carnation, cane...).
A species is exotic "when it is outside its natural distribution area by human action" and becomes invasive when "it naturalizes in the environment, multiplies and competes with native species, displacing them", explained Manuel Miranda, technician of RedEXOS. This is what happens with the cat's tail, very well controlled in Lanzarote, or with the Argentine parrot, whose large number (500 specimens in Arrecife, Playa Honda and Puerto del Carmen) exceeds the competences of the network and requires a unique and coordinated institutional strategy.
Miranda stressed that invasive alien species are responsible for 60% of the loss of global biodiversity, a percentage that rises to 90% in the case of islands. Félix Medina, biologist of the Environment Service of the Cabildo de La Palma, recalled that many species of oceanic islands such as the Canary Islands lost their predatory capacity (thorns, poisons) due to the absence of large herbivores.
Invasive alien species "modify the ecosystem, compete for resources with native species, introduce pathogens and produce hybridizations". This is the case of birds such as the red bengali, imported by hotel establishments for their gardens or the California king snake, released into the natural environment by reptile owners. "Feral domestic species, such as goats, sheep, the arui and the mouflon, are also invasive alien species," Medina recalled. They are able to eat up to 3.5 kilos of plants daily, which means a loss of "10 tons of biodiversity daily in the Canary Islands, a real nonsense".
The rabbit is one of the "most aggressive": it erodes to the point of not allowing natural regeneration. "But the most formidable predator is the cat," he warned. In the Canary Islands, when our pets are in a state of freedom, they affect 175 species. Only in 2014 in La Graciosa, 155 shearwaters and petrels were preyed upon by these domestic felines, responsible for 14% of the extinctions produced throughout history. We must "urgently prioritize their management", asked the expert.
In the round table that brought the conference to an end, Jonay Cubas, PhD in Biodiversity and Conservation, warned that the Canary Islands flora "is agonizing due to climate change and invasive alien species". Pablo García, environmentalist of the Isla de La Graciosa Center, of the Autonomous Body of National Parks, pointed out the importance of becoming aware that we must also protect other species that are not our pets. The health of the ecosystem depends on it.
The experts concluded that "prevention, institutional coordination and environmental education" are essential to protect the Canary Islands biodiversity.
