Exploring the benefits of a tropical, large-scale marine protected area for breeding seabirds, per mare, per terram
Carr, P
Date: 1 November 2021
Publisher
University of Exeter
Degree Title
PhD Biological Sciences
Abstract
Debate continues in scientific and popular literature into the benefits of large scale marine protected areas (> 100,000 km2
- LSMPAs), especially for top
predators. Of top marine predators, seabirds are deemed to be the easiest to
study due to their ease of observation and often colonial breeding. The
Important Bird and ...
Debate continues in scientific and popular literature into the benefits of large scale marine protected areas (> 100,000 km2
- LSMPAs), especially for top
predators. Of top marine predators, seabirds are deemed to be the easiest to
study due to their ease of observation and often colonial breeding. The
Important Bird and Biodiversity Areas (IBAs) programme is a method of
identifying the most important places for birds. IBAs are identified using a
globally agreed standardised set of data-driven criteria and thresholds. In this
thesis I explore the benefits of a LSMPA for top predators. I use IBAs on land
and at sea with seabirds as the qualifying species as the means of exploration
and the tropical British Indian Ocean Territory (Chagos) MPA (hereafter BIOT
MPA) as the study system. Red-footed Booby Sula sula rubripes is the focal
species of the thesis.
My research demonstrates that the BIOT MPA is extremely important regionally
and globally for biodiversity and provides a breeding sanctuary for ≈ 282,000
pairs of seabirds of 18 species annually, four of which breed in internationally
important numbers that trigger IBA status. However, invasive Ship Rats Rattus
rattus and abandoned coconut Cocos nucifera plantations are severely
restricting the islands that seabirds can breed on. I calculate by eradicating rats
and managing invasive coconut plantations on a single 123 ha island, the
number of seabirds breeding in the BIOT MPA could more than double. At sea,
I identified sites that meet IBA status and due to their overlapping boundaries
form a single ‘super’ IBA that covers ≈ 10% of the MPA.
The terrestrial and marine sites I have identified within the MPA warrant
enhanced protection. Red-footed Booby is deemed an umbrella species and
therefore protecting the feeding and breeding habitat of this species will afford
protection on a suite of other species, including sub-surface predators. I
suggest this thesis is a foundation stone from which further research into marine
biodiversity hotspots in the central Indian Ocean can be launched. This thesis
supports the growing evidence that tropical LSMPAs are beneficial to top
predators and unequivocally demonstrates that the BIOT MPA encompasses
the early stages of breeding of a highly mobile, top predator.
Doctoral Theses
Doctoral College
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