Global-scale characterization of turning points in arid and semi-arid ecosystems functioning
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- EGU2020-13375-print
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Ecosystems in drylands are highly susceptible to changes in their way of
functioning due to extreme and prolonged droughts or anthropogenic
perturbation. Long-standing pressure, from climate or human action, may
result in severe alterations in their dynamics. Moreover, changes in
dryland ecosystems functioning can take place abruptly (Horion et al.,
2016). Such abrupt changes may have severe ecological and economic
consequences, disturbing the livelihood of drylands inhabitants and
causing increased poverty and food insecurity. Considering that drylands
cover 40% of Earth's land surface and are home to around one-third of
the human population, detecting and characterizing hotspots of abrupt
changes in ecosystem functioning (here called turning points) becomes
even more crucial.BFAST, a time series segmentation technique, was used
to detect breakpoints in time series (1982-2015) of rain-use efficiency.
An abrupt change in rain-use efficiency time series points towards a
significant change in the way an ecosystem responds to precipitation,
allowing the study of turning points in ecosystem functioning in both
natural and anthropogenic landscapes. Moreover, we here proposed a new
typology to characterize turning points in ecosystem functioning, which
takes into account the trend in ecosystem functioning before and after
the turning point, as well as differences in the rate of change. Case
studies were used to evaluate the performance of the new typology.
Finally, ancillary data on population density and drought were used to
have some first insights about the potential determinants of hotspots of
turning point occurrence.Our results showed that 13.6% of global
drylands presented a turning point in ecosystem functioning between 1982
and 2015. Hotspots of turning point occurrence were observed in North
America (where 62.6% of the turning points were characterized by a
decreasing trend in ecosystem functioning), the Sahel, Central Asia, and
Australia. The last three hotspot regions were mainly characterized by a
positive trend in ecosystem functioning after the turning point. The
ancillary data pointed to an influence of both droughts and human action
on turning point occurrence in North America, while in Asia and
Australia turning point occurrence was higher in areas with higher
anthropogenic pressure. In the grasslands of the Sahel, turning points
were potentially related to drought. By detecting where and when
hotspots of turning points occurred in recent decades, and by
characterizing the trends in ecosystem functioning before and after the
turning points, we advanced towards better supporting decision making
related to ecosystems conservation and management in drylands. Moreover,
we provided first insights about the drivers of ecosystem functioning
change in hotspots of turning point occurrence in global drylands
(Bernardino et al., 2019). References:Bernardino PN, De Keersmaecker W,
Fensholt R, Verbesselt J, Somers B, Horion S (2019) Global-scale
characterization of turning points in arid and semi-arid ecosystems
functioning. Manuscript submitted for publication.Horion S, Prishchepov
A V., Verbesselt J, de Beurs K, Tagesson T, Fensholt R (2016) Revealing
turning points in ecosystem functioning over the Northern Eurasian
agricultural frontier. Global change biology, 22, 2801-2817.
Originalsprog | Engelsk |
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Publikationsdato | 1 maj 2020 |
Antal sider | 2 |
DOI | |
Status | Udgivet - 1 maj 2020 |
Begivenhed | EGU General Assembly 2020: Online - Online Varighed: 4 maj 2020 → 8 maj 2020 https://www.egu2020.eu/ |
Konference
Konference | EGU General Assembly 2020 |
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Lokation | Online |
Periode | 04/05/2020 → 08/05/2020 |
Internetadresse |
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