The influence of climate change on the future distribution of two Thymus species in Iran: MaxEnt model-based prediction.

Within a few decades, the species habitat was reshaped at an alarming rate followed by climate change, leading to mass extinction, especially for sensitive species. Species distribution models (SDMs), which estimate both present and future species distribution, have been extensively developed to investigate the impacts of climate change on species distribution and assess habitat suitability. In the West Asia essential oils of T. daenensis and T. kotschyanus include high amounts of thymol and carvacrol and are commonly used as herbal tea, spice, flavoring agents and medicinal plants. Therefore, this study aimed to model these Thymus species in Iran using the MaxEnt model under two representative concentration pathways (RCP 4.5 and RCP 8.5) for the years 2050 and 2070. The findings revealed that the mean temperature of the warmest quarter (bio10) was the most significant variable affecting the distribution of T. daenensis. In the case of T. kotschyanus, slope percentage was the primary influencing factor. The MaxEnt modeling also demonstrated excellent performance, as indicated by all the Area Under the Curve (AUC) values exceeding 0.9. Moreover, based on the projections, the two mentioned species are expected to undergo negative area changes in the coming years. These results can serve as a valuable achievement for developing adaptive management strategies aimed at enhancing protection and sustainable utilization in the context of global climate change.

Habitat potential modelling and the effect of climate change on the current and future distribution of three Thymus species in Iran using MaxEnt.

Over the course of a few decades, climate change has caused a rapid and alarming reshaping of species habitats, resulting in mass extinction, particularly among sensitive species. In order to investigate the effects of climate change on species distribution and assess habitat suitability, researchers have developed species distribution models (SDMs) that estimate present and future species distribution. In West Asia, thyme species such as T. fedtschenkoi, T. pubescens, and T. transcaucasicus are rich in thymol and carvacrol, and are commonly used as herbal tea, spice, flavoring agents, and medicinal plants. This study aims to model the distribution of these Thymus species in Iran using the MaxEnt model under two representative concentration pathways (RCP 4.5 and RCP 8.5) for the years 2050 and 2070. The objective is to identify the crucial bioclimatic (n = 5), edaphic (n = 1), and topographic (n = 3) variables that influence their distribution and predict how their distribution might change under various climate scenarios. The findings reveal that the most significant variable affecting T. fedtschenkoi and T. pubescens is altitude, while soil organic carbon content is the primary factor influencing the distribution of T. transcaucasicus. The MaxEnt modeling demonstrates excellent performance, as indicated by all the area under the curve (AUC) values exceeding 0.9. Based on the projections, it is expected that these three thyme species will experience negative area changes in the coming years. These results can serve as a valuable tool for developing adaptive management strategies aimed at enhancing protection and sustainable utilization in the context of global climate change. Special attention should be given to conserving T. fedtschenkoi, T. pubescens, and T. transcaucasicus due to their significant habitat loss in the future.

Impact of climate change on the future distribution of three Ferulago species in Iran using the MaxEnt model.

The decline of habitats supporting medicinal plants is a consequence of climate change and human activities. In the Middle East, Ferulago angulata, Ferulago carduchorum, and Ferulago phialocarpa are widely recognized for their culinary, medicinal, and economic value. Therefore, this study models these Ferulago species in Iran using the MaxEnt model under two representative concentration pathways (RCP4.5 and RCP8.5) for 2050 and 2070. The objective was to identify the most important bioclimatic (n = 6), edaphic (n = 4), and topographic (n = 3) variables influencing their distribution and predict changes under various climate scenarios. Findings reveal slope percentage as the most significant variable for F. angulata and F. carduchorum, while solar radiation was the primary variable for F. phialocarpa. MaxEnt modeling demonstrated good to excellent performance, as indicated by all the area under the curve values exceeding 0.85. Projections suggest negative area changes for F. angulata and F. carduchorum (i.e., predictions under RCP4.5 for 2050 and 2070 indicate -34.0% and -37.8% for F. phialocarpa, and -0.3% and -6.2% for F. carduchorum; additionally, predictions under RCP 8.5 for 2050 and 2070 show -39.0% and -52.2% for F. phialocarpa, and -1.33% and -9.8% for F. carduchorum), while for F. phialocarpa, a potential habitat increase (i.e., predictions under RCP4.5 for 2050 and 2070 are 23.4% and 11.2%, and under RCP 8.5 for 2050 and 2070 are 64.4% and 42.1%) is anticipated. These insights guide adaptive management strategies, emphasizing conservation and sustainable use amid global climate change. Special attention should be paid to F. angulata and F. carduchorum due to anticipated habitat loss. Integr Environ Assess Manag 2024;20:1046-1059. © 2024 SETAC.

Using climatic variables alone overestimate climate change impacts on predicting distribution of an endemic species.

Plant species distribution is constrained by both dynamic and static environmental variables. However, relative contribution of dynamic and static variables in determining species distributions is not clear and has far reaching implications for range change dynamics in a changing world. Prunus eburnea (Spach) Aitch. & Hemsl. is an endemic and medicinal plant species of Iran. It has rendered itself as ecologically important for its functions and services and is currently in need of habitat conservation measures requiring investigation of future potential distribution range. We conducted sampling of 500 points that cover most of Iran plateau and recorded the P. eburnea presence and absence during the period 2015-2017. In this study, we evaluated impacts of using only climatic variables versus combined with topographic and edaphic variables on accuracy criteria and predictive ability of current and future habitat suitability of this species under climate change (CCSM4, RCP 2.6 in 2070) by generalized linear model and generalized boosted model. Models' performances were evaluated using area under the curve, sensitivity, specificity and the true skill statistic. Then, we evaluated here, driving environmental variables determining the distribution of P. eburnea by using principal component analysis and partitioning methods. Our results indicated that prediction with high accuracy of the spatial distribution of P. eburnea requires both climate information, as dynamic primary factors, but also detailed information on soil and topography variables, as static factors. The results emphasized that environmental variable grouping influenced the modelling prediction ability strongly and the use of only climate variables would exaggerate the predicted distribution range under climate change. Results supported using both dynamic and static variables improved accuracy of the modeling and provided more realistic prediction of species distribution under influence of climate change.

BDNF modifies hippocampal KCC2 and NKCC1 expression in a temporal lobe epilepsy model.

Excitatory GABA actions, induced by altered expression of chloride transporters (KCC2/NKCC1), can contribute to seizure generation in temporal lobe epilepsy. In the present study, we evaluated whether BDNF administration can affect KCC2/NKCC1 expression, ictogenesis and behavioral alterations in this paradigm. Status epilepticus was induced in male rats with pilocarpine, followed by a treatment of either a single high dose or multiple injections of BDNF during the latent phase of temporal lobe epilepsy. Chloride transporters expression, spontaneous recurrent seizures, and hyperexcitability post-seizural behaviors were evaluated after treatment. NKCC1 protein expression was markedly upregulated, whereas that of KCC2 was significantly downregulated in epileptic hippocampi compared to intact controls. Application of BDNF (both single high dose and multiple injections) increased KCC2 expression in epileptic hippocampi, while NKCC1 expression was downregulated exclusively by the single high dose injection of BDNF. Development of spontaneous recurrent seizures was delayed but not prevented by the treatment, and hyperexcitability behaviors were ameliorated for a short period of time. To prevent GABA-A mediated depolarization and design appropriate treatment strategies for temporal lobe epilepsy, chloride transporters can be considered as a target. Future studies are warranted to investigate any possible therapeutic effects of BDNF via altering chloride transporters expression.

An Iranian herbal-marine medicine, MS14, ameliorates experimental allergic encephalomyelitis.

Multiple sclerosis is an inflammatory and demyelinating disease of the central nervous system which mainly affects young adults. To overcome wide spectrum troublesome symptoms of multiple sclerosis which affects the quality of life both in patients and their families, new drugs and remedies have been examined and offered. The preclinical beneficial effects of different medicines have mostly been examined in an animal model of multiple sclerosis called experimental allergic encephalomyelitis (EAE). In this study we have tested a traditionally used natural (herbal-marine) product called MS(14) in EAE mice. EAE mice were fed with MS(14) containing diet (30%) on the immunization day and monitored for 20 days. The results show that while clinical scores and therefore severity of the disease was progressive in normal-fed EAE mice, the disease was slowed down in MS(14)-fed EAE mice. Moreover, while there were moderate to severe neuropathological changes in normal fed mice, milder changes were seen in MS(14) fed mice.