Predicting the distributions of Egypt's medicinal plants and their potential shifts under future climate change

Abstract

Climate change is one of the most difficult of challenges to conserving biodiversity, especially for countries with few data on the distributions of their taxa. Species distribution modelling is a modern approach to the assessment of the potential effects of climate change on biodiversity, with the great advantage of being robust to small amounts of data. Taking advantage of a recently validated dataset, we use the medicinal plants of Egypt to identify hotspots of diversity now and in the future by predicting the effect of climate change on the pattern of species richness using species distribution modelling. Then we assess how Egypt's current Protected Area network is likely to perform in protecting plants under climate change. The patterns of species richness show that in most cases the A2a 'business as usual' scenario was more harmful than the B2a 'moderate mitigation' scenario. Predicted species richness inside Protected Areas was higher than outside under all scenarios, indicating that Egypt's PAs are well placed to help conserve medicinal plants.

Fig 1. Boxplot of the Maxent predictive performance based on mean AUC and TSS scores.

Fig 2. Predicted patterns of species richness using binary distributions for the present-day (‘current’) and into the future (2020, 2050, 2080) under two climate-change scenarios (A2a and B2a), created by adding together the maps of all 114 species and assuming unlimited dispersal.

The colours indicate predicted species richness ranging between dark red (high) and blue (low).

Fig 3. Data as in Fig 2, but assuming no-dispersal.

The colours indicate predicted species richness ranging between dark red (high) and blue (low).

Fig 4. Mean of the difference in predicted species richness between inside and outside each of the Egyptian PAs.

This mean is highly significantly different from zero (t323 = 10.1, p<<0.001), and positive, implying that species richness is higher inside than outside the PAs.

Fig 5. Predicted future species turnover (change in species composition), assuming unlimited dispersal.

The colours indicate ranges, from low (blue) to high (red) change in species composition).