Long‐term climate forcings to assess vulnerability in North Africa dry argan woodlands

Abstract

Questions: North African dry woodlands constitute mediterranean climatic ecotone ecosystems of vital importance for human livelihoods and local biodiversity. To improve the basis for managing these key ecosystems, we selected a Tertiary relict woodland (Argania spinosa) in order to clarify the sensitivity to long-term climate change (the present, the past glacial-interglacial cycle and under future scenarios). We also discuss the impact of long-term human land use for the distribution of dry woodlands in North Africa.Location: North Africa.Methods: To assess whether the argan woodland is in equilibrium with current climate, we used species distribution modelling (SDM) to estimate its potential range. Then, SDM was used to estimate its potential distribution during the Last Glacial Maximum (LGM; 21,000 BP) and the Middle Holocene (Mid-Holocene; 6,000 BP). Model predictions for past scenarios were compared with Quaternary palaeorecords to evaluate their accuracy. Finally, we forecasted changes in the potential range to year 2080 to assess its likely future range dynamics.Results: At the LGM, suitable areas occurred at more southern latitudes, where the Sahara Desert currently lies, while suitable areas in the Mid-Holocene shifted northwards, occupying areas similar to those of today. The estimated past distributions are consistent with palaeorecords, providing evidence for the important role of Quaternary climate changes in driving dry woodland range dynamics. The current range-filling constitutes 44% of the potential distribution, probably primarily reflecting anthropic land-use effects. Future climate change is forecast not to cause latitudinal/altitudinal range shifts, but rather an overall range contraction. Conclusions:The models reflect the high sensitivity of the dry woodland ecosystem to past climate changes, in agreement with palaeorecords. The estimated climatic sensitivity also predicts severe range contraction during future climate change. Consequently, management strategies for dry woodlands should be developed to facilitate their in situ survival, particularly by reducing the currently intensive human pressure.

Geomorphodynamics in Argan Woodlands, South Morocco

“…However, another possible explanation for the differences could be due to coastal fog which is caught by the argan trees [97] and precipitates in the tree area. It is a major source of precipitation for the argan trees, since rainfall is very variable in the study areas [22].…”

High genetic diversity and low future habitat suitability: will Cupressus atlantica, endemic to the High Atlas, survive under climate change?

“…Recently, such a pessimistic scenario has also been reported for other endemic trees in North Africa, such as Cedrus atlantica, Juniperus thurifera subsp. africana and Argania spinosa (Alba-Sánchez et al 2015;Arar et al 2019;Taib et al 2020). For those species, a significant range contraction and even local extinctions are expected by the end of 2100.…”

Microrefugia, Climate Change, and Conservation of Cedrus atlantica in the Rif Mountains, Morocco

“…The discrepancy between the observed and simulated ranges may be linked to the additional effect of human activities which had a major impact on all mountain forests in Morocco (Reille, 1977;Lamb et al, 1991;Ajbilou et al, 2006), accelerating the Atlas cedar extinction along the lower edge of its range (Cheddadi et al, 2015). Such human influences are thought to underlie several periods of deforestation over the last three millennia in many North African forest ecosystems (Mercuri et al, 2011;Alba-Sánchez et al, 2015).…”