Improving MPA Management

Rat Eradication on Ile Vache Marine: A Success!

Original post:

Successful Conservation Intervention in the Chagos Archipelago.

Peter Carr and his team with the Chagos Conservation Trust have proudly announced the successful eradication of rats from Ile Vache Marine.

The island sits within the British Indian Ocean Territory and therefore, within its MPA.

Invasive rats have colonized remote islands worldwide alongside human exploration since the 1800s. Ile Vache Marine is a particularly important island as its beaches are used by the two sea turtles species inhabiting BIOT, the hawksbill turtle and green sea turtle. Rats represent a significant threat to these two species populations in BIOT as they feed on their eggs and young. Additionally, they have the same impacts on the populations of native birds present on the island with an added pressure, they can eat adults. The presence of rats reduces bird populations dramatically. This affects the whole surrounding coral reef ecosystem as seabird’s guano represent an essential input of nutrients to the reef. The consequences of rat invasion on remote islands makes their eradication a sensible response plan in restoring lost populations.

The ambitious project of the Chagos Conservation Trust was to eradicate rats from the island in order to allow native species to thrive once more. For an island to be declared “rat free” a minimum period of two years of monitoring must pass to ensure no rat has survived. Therefore, in spring 2017, Peter Carr returned to the island with the hope of finding it rat free. What he found was a thriving ecosystem with native plants recovering as well as healthy invertebrate populations.

Sentinel Species Research

Changing Ratios in Hawksbill and Green Sea-Turtle Hatchlings

Original post:

Male hatchling production in sea turtles from one of the world’s largest marine protected areas, the Chagos Archipelago.

As our world becomes increasingly warm, the effects of these rising temperatures affect species worldwide.

This phenomenon can have a drastic impact on sea turtles especially, as the sex of hatchlings in the nest is determined by temperature (hotter incubation resulting in more females while cooler incubation gives more males).

This climatic disturbance has led sea turtles sex ratio in rookeries around the world to be skewed more towards females, meaning that there are now more females than male hatchlings. Should this trend continue, and coupled with other man-made pressure on the species, it could lead to female only populations and the extinction of turtle species.

A study, conducted by Dr. Nicole Esteban and the turtle team, investigated sand temperatures and their implications for hatchling sex ratios in the British Indian Ocean Territory (BIOT). The results from this study are promising. After collecting data for 2 years they found that sand temperatures were relatively cool during the nesting season of both species especially on sand shaded by vegetation. This predicts a hatchling sex ratio with slightly more males than females. This result is promising as it means that shaded nesting beaches will continue to provide a substantial number of males hatchlings into a female dominated regional population and warming world.

Sentinel Species Research

Satellite Tracking Uncovers Green Turtles’ Ability to Travel Staggering Distances

Original post:

Space tracking reveals turtles’ record-breaking ocean swim.

Core Paper:

A recent study focussing on satellite-tracking of green turtles in the Chagos Archipelago showed that turtles can travel longer distances than previously thought.

Eight green turtles were tagged while nesting on a Chagossian beach, of these eight only one did not travel to distant foraging grounds and preferred to stay in the MPA. Some individuals were tracked all the way to the east coast Africa, about 4000km away.

Green Turtles have evolved to undertake these long migrations across our oceans, when travelling they solely rely on their fat reserves. Scientists are still puzzled in the face of their navigation skills as they find small patches of seagrass in our immense oceans. This high mobility of this animal challenges the ability to protect of isolated MPAs like BIOT. Green turtles are, like most sea turtles, threatened with extinction. It is crucial to establish network of MPAs to allow these species to migrate safely as much as possible.

Unfortunately, international cooperation is needed to create these safe corridors between the already existing large MPAs. Achieving this difficult outcome will also ensure the protection of many species whom are now in dire need of it.