The influence of climate and population density on Buxus hyrcana potential distribution and habitat connectivity

Abstract

Changes in environmental factors, human impact, and interactions between them accelerate the extinction of woody species. Therefore, conservation programs are needed to protect endangered taxa. However, the relationship between climate, habitat fragmentation, and anthropogenic activities and their consequences are still not well understood. In this work, we aimed to evaluate the impact of climate change and human population density on the Buxus hyrcana Pojark distribution range, as well as the phenomenon of habitat fragmentation. Based on species occurrence data throughout the Hyrcanian Forests (north of Iran), the MAXENT model was employed to estimate the potential distribution and suitability changes. Morphological-spatial analysis (MSPA) and CIRCUITSCAPE were used to assess habitat fragmentation and its connectivity. According to the main results obtained from future scenarios, the potential range will significantly decrease due to the lack of suitable climatic conditions. Meanwhile, B. hyrcana may not be able to shift in potentially suitable areas because of human influence and geographic barriers. Under RCP scenarios the extent of the core area would be reduced and the edge/core ratio significantly increased. Altogether, we found negative effects of the environmental change and the human population density on the continuity of habitats of B. hyrcana. The results of the presented work may improve our knowledge connected with in situ and ex situ protection strategies.

Consequence of habitat specificity: a rising risk of habitat loss for endemic and sub-endemic woody species under climate change in the Hyrcanian ecoregion

“…Secondly, a further challenge in species range predictions is the choice of algorithms and climatic predictors, which strongly affect the accuracy of SDMs and are key to ensuring the reproducibility of the methods and thus provide a source of projections uncertainty (Konowalik and Nosol 2021;Zurell et al 2023). Thus, the observed discrepancies between our estimation and the previous SDM projections reported by Alipour and Walas (2023), Taleshi et al (2019) are due to the use of different methodological approaches. One of the major constraints relates to using climate rasters that may fail to capture the effects of topography on microclimate (Gavin et al 2014;Karger et al 2017).…”

“…This applies to boxwood in the Hyrcanian ecoregion, for which the forecasted climate changes may markedly affect the species range across the landscape. Most present-day Buxus hyrcana populations are seriously threatened and devastated by the spread of boxwood blight and box-tree moth (Alipour and Walas 2023;Nacambo et al 2014). Although the genetic diversity in the species currently remains relatively high (Esmaeilnezhad et al 2020;Salehi Shanjani et al 2018), there is a justified concern for the loss of variability, especially if genetic drift becomes a dominant evolutionary force and is accompanied by an observed reduction in population size which are likely to get worse under future climate change.…”

“…Consequently, lowland and sub-montane species, such as Albizia julibrissin, Gleditsia caspica, and Populus caspica are currently reduced to the small patches (Sagheb-Talebi et al 2014). Moreover, according to recent projections for the ecoregion, an alarming reduction in suitable areas for major tree species, including endemic taxa, is expected in the next decades (Ahmadi et al 2020;Alavi et al 2019;Alipour and Walas 2023;Joorabian Shooshtari et al 2017;Mahmoodi et al 2023;Naqinezhad et al 2022;Song et al 2021;Taleshi et al 2019). Among the Hyrcanian endemic trees, a strong reduction of the climatically suitable areas was projected for Acer velutinum (Taleshi et al 2019), Gleditsia caspica (Taleshi et al 2019;Yousefzadeh et al 2022), Parrotia persica (Taleshi et al 2019), Populus caspica , and Buxus hyrcana (Alipour and Walas 2023).…”

“…Moreover, according to recent projections for the ecoregion, an alarming reduction in suitable areas for major tree species, including endemic taxa, is expected in the next decades (Ahmadi et al 2020;Alavi et al 2019;Alipour and Walas 2023;Joorabian Shooshtari et al 2017;Mahmoodi et al 2023;Naqinezhad et al 2022;Song et al 2021;Taleshi et al 2019). Among the Hyrcanian endemic trees, a strong reduction of the climatically suitable areas was projected for Acer velutinum (Taleshi et al 2019), Gleditsia caspica (Taleshi et al 2019;Yousefzadeh et al 2022), Parrotia persica (Taleshi et al 2019), Populus caspica , and Buxus hyrcana (Alipour and Walas 2023). However, a comprehensive study of climate risk assessment for the Hyrcanian endemic and sub-endemic woody species in the ecoregion is still lacking.…”

Predicting the suitable cultivation areas of breadfruit crops Artocarpus altilis (Moraceae) under future climate scenarios in Central Java, Indonesia

“…The four RCPs are called after a hypothetical range of Radiative Forcing values in the year 2100 relative to pre-industrial levels ranging from + 2.6, + 4.5, + 6.0, to + 8.5 W/m 2 (Weyant et al, 2009). RCP2.6 is optimistic scenario estimating about 1°C increase before the end of XXI century, RCP4.5 is moderate scenario estimating 1.8°C increase, and RCP8.5 is pessimistic, scenario estimating about 3.7°C increase (Collins et al, 2013;Alipour and Walas, 2023). Here, we selected the RCP2.6 as the minimum emission representative and RCP8.5 as the maximum emission representative models to simulate habitat suitability distributions of A. altilis in the 2050s and 2070s (Beaumont et al, 2008).…”