[OANNES Foro] Key ecological areas under disproportionate pressure from human activities around Antarctica

[Mario Cabrejos]

NATURE
<https://www.nature.com/articles/s41586-020-2126-y?WT.ec_id=NATURE-202003&sa
p-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#article-info>
Published: 18 March 2020

DOI  <https://doi.org/10.1038/s41586-020-2126-y>
https://doi.org/10.1038/s41586-020-2126-y

Tracking of marine predators to protect Southern Ocean ecosystems

 
<https://www.nature.com/articles/s41586-020-2126-y?WT.ec_id=NATURE-202003&sa
p-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#auth-1> Mark A.
Hindell, et al.

Abstract

Southern Ocean ecosystems are under pressure from resource exploitation and
climate change <https://www.nature.com/articles/s41586-020-2126-y#ref-CR1>
1, <https://www.nature.com/articles/s41586-020-2126-y#ref-CR2> 2. Mitigation
requires the identification and protection of Areas of Ecological
Significance (AESs), which have so far not been determined at the
ocean-basin scale. Here, using assemblage-level tracking of marine
predators, we identify AESs for this globally important region and assess
current threats and protection levels. Integration of more than 4,000 tracks
from 17 bird and mammal species reveals AESs around sub-Antarctic islands in
the Atlantic and Indian Oceans and over the Antarctic continental shelf.
Fishing pressure is disproportionately concentrated inside AESs, and climate
change over the next century is predicted to impose pressure on these areas,
particularly around the Antarctic continent. At present, 7.1% of the ocean
south of 40°S is under formal protection, including 29% of the total AESs.
The establishment and regular revision of networks of protection that
encompass AESs are needed to provide long-term mitigation of growing
pressures on Southern Ocean ecosystems.

 

//////////////////////////////////////////////

 

NATURE 18 March 2020 

doi: 10.1038/d41586-020-00640-1

 

Satellite tracking of marine predators in the Southern Ocean has revealed
key ecological areas under disproportionate pressure from human activities.
These results show the value of tracking data for informing conservation
efforts

Predators on track for ocean protection around Antarctica

 <javascript:;> Ana M. M. Sequeira 

Even the most remote marine ecosystems on Earth — such as those at high
latitudes, including in the Southern Ocean around Antarctica — can no longer
be considered pristine
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR1> 1. The
effects of humans on marine ecosystems now have a global footprint
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR2> 2–
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR4> 4, and
mitigation of associated threats requires knowledge of the areas of
particular ecological and biological significance. Such areas sustain the
healthy functioning of marine ecosystems and should therefore be protected.
<https://www.nature.com/articles/s41586-020-2126-y> Writing in Nature,
Hindell et al.
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR5> 5 report
analyses of tracking data for marine species that reveal these key areas in
the Southern Ocean.

The waters of the Southern Ocean encircle the Earth through the Drake
Passage, the ocean region between the tip of South America and Antarctica.
Because of this passage, the Southern Ocean has a key role in global climate
and ocean circulation
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR6> 6. This
ocean is also home to a unique range of marine fauna, including many
charismatic predators, such as penguins (Fig. 1) and seals, as well as the
precious Antarctic krill (Euphausia superba). These krill are at the base of
the marine food web, and, alongside species of toothfish (Dissostichus
eleginoides and Dissostichus mawsoni), are the target of the largest fishing
industries in the Southern Ocean
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR7> 7,
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR8> 8. The
fisheries compete with animals for food resources, and fishing activities
along with the pressures from climate change are raising concerns about the
possibility of ecosystem collapses there
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR8> 8,
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR9> 9.

The Commission for the Conservation of Antarctic Marine Living Resources is
the main management body for the Southern Ocean, and is tasked with ensuring
the preservation of this ecosystem. To succeed, the commission needs to take
precautionary steps, including the establishment of more and better-designed
marine reserves as has been suggested
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR8> 8, and
sites for these should be chosen on the basis of knowledge of the
whereabouts of ecologically significant marine areas
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR10> 10.
However, accurately defining these areas in a highly dynamic, changing
environment is challenging.

Monitoring predators at the top of a marine food web can help with this
task. Such predators migrate within and between ecosystems, and can be used
as indicator species
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR11> 11 — those
able to provide information on the status of an ecosystem or habitat if
alterations occur in their movement patterns, behaviour or reproductive
success. In particular, tracking top predators can assist with identifying
the areas that they use most, which can be considered as regions of great
ecosystem importance, not only for the predators but also for a wide range
of other species
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR11> 11.
Indeed, tracking data are increasingly being used to inform conservation
policy around the world
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR12> 12, and
have been used to quantify the extent of spatial overlaps between species
and fishing activities globally
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR3> 3.

Hindell et al. report analyses of tracking data from 4,060 individuals of 17
species of marine predators (seabirds and mammals), and suggest a way to use
such data to predict key ecological regions in the Southern Ocean. Tracking
data were collected between 1991 and 2016 using electronic tags attached to
the animals. These tags provided location estimates (obtained using
satellite information or other methods) as the animals migrated. The authors
used some of these data (for 2,823 individuals) to develop predictive models
to identify crucial habitats in the Antarctic region for all of the predator
species combined. These integrated results provide a spatially defined
assessment of areas of high biodiversity that includes species across
multiple levels of the food chain (termed trophic levels) in the Southern
Ocean.

Defining a single, integrated result from such varied data sets and from so
many species is a complex undertaking. Predators in the Southern Ocean
include a large range of species from across different taxonomic groups.
These include species living in the Antarctic region and species residing
immediately north of it (in the sub-Antarctic), all with different diets and
patterns of movement. The authors used a series of data-processing steps to
generate a value they termed ‘habitat importance’, which they predicted
using data across all of these species together (assemblage-level maps). To
do this, Hindell and colleagues first mapped habitat importance for the
species living in the Antarctic separately from those living in the
sub-Antarctic, and then selected the maximum habitat-suitability values in
those two maps to generate an overall assemblage-level map for all of the
predator species combined.

Finally, the authors defined the regions in the top 10% of their calculated
habitat importance value as the areas of the most ecological significance in
the Southern Ocean. This final step was a central part of their study. It
enabled comparisons to be made between the areas of ecological significance
and the areas affected by human activities, as well as between the levels of
existing protection inside and outside these areas.

Hindell and co-workers report that the predicted areas of ecological
significance they identified match the ocean regions of known elevated
productivity for Antarctic krill
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR13> 13 and for
other organisms at the base of the food web, including myctophids
(lanternfish)
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR14> 14. This
result is consistent with the idea that marine predators can be used as
indicators to identify areas of ecological significance. The authors report
the particularly striking finding that a disproportionately higher level of
human pressures (fishing and the effects of climate change) occurred inside
rather than outside the areas identified as being of ecological
significance. On the basis of this, the authors recommend that the current
network of protected marine areas in the Southern Ocean be extended. They
confirm that these extensions should include the areas for which protection
is already being planned.

It would have been interesting if the authors had suggested how an approach
similar to theirs could best be used to tackle comparable problems on a
global scale. For example, the authors’ views on the best strategy for
contributing scientific knowledge to inform efforts to protect biodiversity
on the high seas (the waters outside national jurisdictions) would have been
a valuable addition. This topical issue is currently being discussed by the
United Nations General Assembly, and negotiations are under way to develop
an international legally binding solution to address the problem
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR15> 15.

Scientists have tracked marine predators for decades
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR3> 3,
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR4> 4,
<https://www.nature.com/articles/d41586-020-00640-1?WT.ec_id=NATURE-202003&s
ap-outbound-id=EAEB07ACFEB1F4DA05CAB1ED16DDE9782F8B5BE5#ref-CR12> 12. It is
time to pool all these existing data sets to address pressing conservation
challenges on a global scale. To succeed, a worldwide movement is needed
within the community of animal-tracking researchers, to drive the sharing of
these data and to combine them with information about human activities at
sea. Combining such information will deliver much-needed evidence of the
extent of existing threats, to inform managers and policymakers in a timely
manner. As Hindell and colleagues state, the Southern Ocean has the
potential to provide an example of how “science, policy and management can
interact to meet the challenges of a changing planet”, and their work
highlights a pathway for how best to direct policy efforts.

 



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