Forecasting climate change effects on the potential distribution of Zhumeria Majdae as an endangered monotypic endemic species: a maxent modeling approach

Abstract

Medicinal plants are invaluable sources of bioactive compounds and continue to serve as primary medicine for many people worldwide, despite advances in pharmaceuticals. Their recognition has increased with the popularity of herbal products, yet many are vanishing rapidly. Climate change further threatens these resources, making their conservation a pressing concern. This study aimed to evaluate current range and the potential impact of climate change on the future distribution of Zhumeria majdae, an endangered and endemic medicinal species in Iran, and to identify priority areas for its conservation. Using 56 occurrence records and 7 environmental variables, the MaxEnt model was employed to project current and future habitat suitability under two climate scenarios (RCP 4.5 and RCP 8.5) for the 2050s and 2070s. The model performed excellently (AUC = 0.977, TSS = 0.807 ). Among the variables used, solar radiation contributed the most (26%), followed by slope (12%), pH index (2.5%), Bio6 (1.1%), Bio19 (26.3%), Bio10 (0.7%), and Bio18 (31.3%). The results predicted suitable range in Hormozgan, South of Kerman and Fars provinces. Also, modeling projected a notable shift in the geographic distribution of Z. majdae under climate change scenarios. The suitable habitat is projected to expand by 20.12% under RCP 4.5 and by 29.95% under RCP 8.5 in the 2050s. In the 2070s, an increase of 21.63% is expected under RCP 4.5, while a slight contraction of 1.15% is projected under RCP 8.5. Based on these findings, it is recommended to prioritize conservation efforts in areas projected to remain suitable in both current and future climates. Establishing in-situe and ex-situ conservation sites, introduce protected areas in new habitat projected, and initiating habitat restoration in emerging suitable zones could enhance the species' long-term survival prospects.

Keywords: Conservation; Global warming; Habitat suitability; Iran; MaxEnt model.

Fig. 1

Geographical distribution of Zhumeria majdae occurrence points (blue dots) overlaid on the digital elevation model (DEM) of Iran

Fig. 2

Predicted habitat suitability response of Z. majdae to environmental variables

Fig. 3

Current potential habitat suitability map of Z. majdae in southern Iran. The map shows the spatial distribution of suitable habitats based on current climatic and environmental conditions. Habitat suitability is classified into four categories based on predicted occurrence probability: Very low suitability (0–0.25), Low suitability (0.25–0.5), Moderate suitability (0.5–0.75), High suitability (0.75–1.0)

Fig. 4

Area of predicted habitat suitability classes for Z. majdae under different climate changes scenarios (RCP 4.5 and RCP 8.5 for 2050 and 2070). Values are presented in million square kilometers (10⁶ km²) of the total study area

Fig. 5

Spatiotemporal projections of suitable habitat for Z. majdae under RCP 4.5 and RCP 8.5 climate change Scenarios in Southern Iran (2050 and 2070). A; RCP4.5-2050, B; RCP8.5-2050, C; RCP4.5-2070, D: RCP8.5-2070

Fig. 6

Latitudinal and altitude distribution of suitable habitat for Z.majdae under current and future climate scenarios (RCP 4.5 and RCP 8.5 for 2050 and 2070)

Fig. 7

Projected stable habitats for Zhumeria majdae under a pessimistic climate change scenario for the year 2070, overlaid with current protected areas