麻豆淫院

A good wildlife management plan must include information on their migratory processes if the conservation of species, particularly endangered species, is to be improved. In the marine environment, for example, regulating fishing activity in certain wintering areas could improve and complement conservation and protection measures carried out along the breeding grounds.

These are some of the conclusions of the featured on the cover of the journal Diversity and Distributions and led by experts from the Seabird Ecology Lab of the Faculty of Biology and the Biodiversity Research Institute (IRBio) of the University of Barcelona.

The new study analyzes one of the largest and most comprehensive databases ever compiled on the migratory behavior of Cory's shearwater. These data include up to 1,346 migratory movements of 805 individuals from 34 breeding colonies of three closely related Cory's shearwater species: the Mediterranean Cory's shearwater (Calonectris diomedea), the Atlantic Cory's shearwater (C. borealis) and the Cape Verde shearwater (C. edwardsii).

This is the first paper to assess the migratory behavior and environmental preferences throughout the breeding range of these three species. The study, which provides a broad and comprehensive view of the migratory behavior of these taxa, results from the scientific collaboration of up to 12 research teams from seven countries around the world.

Studying migratory connectivity to improve protection

Migratory seabirds spend most of their lives at sea; this is the case of the Cory's shearwater (Calonectris diomedea) cited in the study. Knowing the wintering areas鈥攚ith all the existing connections with the different breeding areas鈥攊s a key factor in establishing conservation measures and designing efficient marine protected areas (MPAs). In these migratory species, the measure of the interconnection between the different breeding populations and the wintering populations is known as migratory connectivity.

The new study combines the estimation of migratory connectivity with the environmental habitat preferences of up to three Cory's shearwater species. "The results obtained help us to understand not only how the three species migrate and behave in wintering areas, but also how this migratory behavior may have played a role in the evolutionary segregation of the three taxa," says Ra眉l Ramos, associate professor at the Department of Evolutionary Biology, Ecology and Environmental Sciences of the Faculty of Biology.

"When a species has high migratory connectivity, individuals breeding in the same populations or in proximity to each other also tend to winter together and different breeding populations do not tend to mix during wintering. Conversely, when migratory connectivity is low, individuals from different breeding populations mix in more or less common wintering areas," explains Ramos.

"In the case of seabirds, the impact of global warming or different human activities on the marine environment can alter the migratory connectivity of these species," he continues.

As the researcher Virginia Morera Pujol, first author of the study, points out, "If the protection measures provide for a single wintering area for a species with very low migratory connectivity, the benefit for the species will be minimal.

"In turn, disturbances in a specific wintering area of a species with high migratory connectivity could cause the local extinction of the species in one of its breeding populations because all individuals in that particular population would be affected," she says.

Migratory behavior and gene flow between populations

The study also reveals how the three Cory's shearwater species mostly preserve their migratory identity and explore quite different wintering areas.

"Despite this general behavior, we have also found that birds breeding in the area of the Strait of Gibraltar (the contact area between the Atlantic and Mediterranean species) show an intermediate migratory behavior between the two taxa. This result would indicate some gene flow between these two shearwaters, and that the segregation of the three species was probably facilitated, in part, by differences in migratory behavior," says Professor Jacob Gonz谩lez-Sol铆s, head of the Seabird Ecology Lab.

From the Mediterranean to the American shores

The paper warns that the wintering areas described have high fishing pressure, which makes the stocks more vulnerable to by-catches. Other non-lethal disturbances have also been identified, such as overfishing and a reduction in available food, which could be indirect causes of population decline in the medium and long term.

"This is particularly critical for the Cape Verde Cory's shearwater, a species endemic to the archipelago and which only breeds on these islands. Our study shows that the only wintering area for this species is on the Argentinean and Brazilian coasts, and therefore any disturbance in this area would be very detrimental to the entire species," warn the authors.

The necessary internationalization of migration studies

Access to oceanic birds for the study of their movements is one of the great obstacles to scientific activity. In the last couple of decades, new remote tracking technologies鈥攚ith small, lightweight devices so as not to hinder the birds' maneuverability鈥攈ave facilitated fieldwork and the study of these oceanic birds, which are only accessible during the breeding season, when they incubate their clutches and breed in deep burrows, usually on islands and islets that are usually uninhabited.

International collaboration has made it possible to address the cost and logistics required for this study, which puts the conservation and protection of seabirds with a wide geographical range at the center of interest, thanks to the enormous volume of data contributed by different teams from all over the world.