4.1. Range shift of Z. spina-christi and Z.
nummularia
The present geographical range ofZ. spina-christi is
primarily concentrated in the southern regions of Fars, parts of
Bushehr, the southern and western portions of Khuzestan, as well as
areas to the south of Kohgiluyeh-Boyar Ahmad and Kerman provinces.
Climatically suitable habitats are limited in the country’s southeastern
part, specifically in Hormozgan and Sistan-Baluchistan. The
Khalijo-Omanian zone, a subregion of the Saharo-Sindian region in Iran,
encompasses this area. This phytogeographical region can be further
divided into two distinct territories: Khalijio-Omani. These territories
exhibit ecological differences, with varying climates and higher
temperatures along the Omani coasts. The average temperature in this
zone tends to increase from west to east (Sagheb Talebi et al., 2014).
Within the Khaliji territory, Z. spina-christi plays a pivotal
role. In the Omani territory, the prevailing plant community consists
mainly of Acacia genus, which are paramount in the region’s woody
flora (Sagheb Talebi et al., 2014). The decrease in habitat suitability
for Z. spina-christi in southeastern Iran reflects the shifting
plant communities. Our study has illuminated significant distinctions
between these two ecological zones. In an optimistic scenario (i.e.,
SSP-126), during two periods (2041-2071 and 2071-2100), the
spatial distribution of Z.
spina-christi is expected to expand slightly into the central parts of
Fars and the western regions of Khuzestan. However, under the SSP-585
scenario for the 2041-2070 period, suitable habitats are projected to
fragment and diminish in southern Kerman and Khuzestan. Conversely,
habitat expansion and extension are anticipated in Fars towards higher
latitudes.
In light of the temperature increase projected in scenario SSP-585, the
period from 2071 to 2100 may witness the contraction and reduction of
local habitats in southern Kerman while new suitable habitats emerge in
the northwest of Kerman. Fars province is expected to experience a shift
in suitable habitats towards higher latitudes, and suitable habitat is
anticipated to develop in South Khorasan province, where the presence ofZ. spina-christi presence
has not been previously
documented. In summary, the overall trend for the distribution ofZ. spina-christi is expected to increase. Several global studies
have reported similar patterns of species range changes, including
Ksiksi et al. (2019), Liu et al. (2021), Singh et al. (2022), and
Koldasbayeva et al. (2022).
As for Z. nummularia , its current range is primarily located in
the southwestern and western regions of the country, covering an area of
approximately 23,000 square kilometers. Typically, this species is
observed and recorded as a companion species within Z.
spina-christi vegetation communities, but they do not form distinct
plant communities. The habitat suitability ofZ. nummularia in the
future, under the optimistic SSP-126 scenario for the
periods of 2041-2070 and
2071-2100, may result in the elimination and possible local extinction
of suitable habitats for this species in Fars, Bushehr, and
Kohgiluyeh-Boyar Ahmad, with a reduction in existing habitats in
Khuzestan. Conversely, in the pessimistic SSP-585 scenario and the
2041-2070 periods, there is an anticipation of a slight expansion of
this species’ spatial distribution in Khuzestan province, extending to
higher latitudes.
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However, under the climatic scenario SSP-585 from 2071 to 2100, this
species’ habitat is projected to experience widespread contraction and
extinction. This will destroy all suitable habitats for Z.nummularia in Fars,
Bushehr, Kohgiluyeh-Boyar Ahmad, and southern Khuzestan, while new
habitats will emerge at higher latitudes in Ilam province. Ultimately,
the overall trend for the distribution of Z. nummularia is
expected to decrease. Various studies support the observed pattern of
changes in Z. nummularia distribution, including those conducted
by Tarnian et al. (2021) and Khanal et al. (2022).Top of Form