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Desert locusts : New risks in the light of climate change

ScienceDaily (September 11, 2017)

Titre : Desert locusts : New risks in the light of climate change

ScienceDaily (September 11, 2017)

The desert locust is an invasive species that is both well known and feared because of the large-scale agricultural damage it can cause. It is particularly closely monitored, to prevent the risks of outbreaks and invasions. Climate change could modify its distribution area, meaning a new threat to agriculture, according to a study.

The desert locust has two sub-species, one (currently the more dangerous from an agricultural point of view) north of the equator, and the other (lesser known) in southern Africa. The research results showed that although the two sub-species occupy different climate niches in their respective recession zones, they have kept their environmental niches throughout their evolution. This niche maintenance implies that were the climate in southern Africa to become more similar to that in the North, the sub-species from the South could become as dangerous as the one from the North. Moreover, in the light of climate change, the available large-scale forecasts suggest that the southern sub-species is likely to spread. The northern sub-species, for its part, is likely to encounter more extreme arid conditions that could shrink its overall distribution area during remissions. However, that shrinkage would primarily concern the hyper-arid heart of the Sahara and not the desert locust outbreak area, from which the first hopper bands or adult swarms start out. Another, more worrying consequence of climate change is the likely local spread on the fringes of the current geographical distribution area, such as the coastal Sahel in the South.

The researchers responsible for this study concluded that the existing locust monitoring and management practices and capacities in northern Africa should be maintained, and recommended greater vigilance on the southern and northern fringes of the current distribution area. In southern Africa, the possibility of the southern sub-species becoming a greater threat to agriculture should be watched particularly closely, notably as regards its gregarization capacity under new climate conditions. Beyond the uncertainties linked to modelling of the distribution area for a given species, the study showed that the preventive management strategy for this major pest cannot be seen to be set in stone. It must be reviewed constantly to take account not only of possible, foreseeable climate changes, but also of changes in the socioeconomic context. The CIRAD research team is continuing to work on the desert locust, in the aim of improving management of the pest by taking account of its many aspects and considering it as a complex adaptive system.

Story Source  : CIRAD

Annonce (ScienceDaily)

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