مجله بوم شناسی کاربردی
پیاپی 38 (زمستان 1400)

Predicting the effect of climate change on the distribution of valuable and endangered plant species is essential for their conservation and management. In this study, the MaxEnt model and 10 environmental variables were used to predict the current and future distribution of E. amoenum and E. italicum in response to climate change. Also, to predict the effect of climate change in the future (the 2050s and 2070s), two climate scenarios of RCP 2.6 and RCP8.5 were used under the CCSM4 general circulation model. Evaluating the accuracy of the models based on the AUC index indicates their excellent performance (<0.9). Resutls  of this study reveal that the most important variables affecting the distribution of E. amoenum species are slope (38.8%), annual temperature range (11.5%), and precipitation in the driest season (31.9%) are. Also, the solar radiation (37.6%), slope (36.4%), and the average temperature of the coldest season (11.5%) are the most important environmental factors affecting the distribution of E. italicum. In addition, the results show that the distribution of the studied species will decrease in response to climate change and under RCP2.6 and RCP8.5 in the 2050s and 2070s. Therefore, the results of this study emphasize the need to develop  conservation strategies to prevent the extinction of these species.

The purpose of this study was to analyze the strengths, weaknesses, threats and opportunities in the conservation of Baluchistan black bear in the south of Kerman province using the quantitative and qualitative approaches and presenting the sustainable strategic management program for conservation of this species. Using questionnaire, a list of internal and external environmental factors was compile. The relative importance of these factors was weighted and the Strategic Position and Action Evaluation (SPACE) matrix were drawn and then, the various initial strategies were quantified with the formation of the strategic planning matrix. A total of 11 internal strengths, 4 internal weaknesses, 5 external opportunities and 4 external threats were identified. The final score of the internal factors matrix (IFE = 2.01418) shows that, the weaknesses are more than the strengths and the score of the external factors matrix (EFE = 2.07462) shows that there are more threats than opportunities in solving the conflict problem. The results of the SPACE matrix showed that the defensive strategies should be used for the protection of the Black bear in the south of Kerman province. Implementation of environmental assessment studies for development projects in the Black bear habitats was determined as the first modified solution.

Although turtles are the most threatened taxonomic group within the reptile class, we have a very limited understanding of how turtles respond to climate change. Here, we evaluated the effects of climate changes on the geographical distribution of Caspian pond turtle (Mauremys caspica). We used an ensemble approach by combining six species distribution models including artificial neural network, generalized boosted model, generalized linear model, flexible discriminant analysis, random forest and multivariate adaptive regression splines. To predict the future distribution, modelling projection of MRI-CGCM3 was used for the year 2070 under four scenarios of representative concentration pathways (RCP). Based on the findings, the suitable habitat of Caspian pond turtle was estimated to be about 835941 km2 (about 8.73%) of the study area. Our model projections showed that about 26 to 33% of the current suitable habitats will be unsuitable by 2070 due to climate change. The annual precipitation (24.56%), precipitation of wettest quarter (24.28%), precipitation seasonality (16.93%) and temperature seasonality (14.64%) had the highest contribution to model performance of Caspian pond turtles. Overall, our findings emphasize the need for a comprehensive understanding of the complex effects of climate change on the species, specially turtles.

The purpose of this study was to investigate some environmental factors of Zagros forest dieback. In this regard, raster layers of elevation, slope, aspect, hillshade, toposhape and the land formation of Zagros forests in Ilam province were prepared. The distribution map of live and dieback forest cover were also prepared, using Landsat 8 panchromatic images. Then, the percentage of dieback forest cover in each  specific class of the studied factors was calculated, using geographic information system (GIS). Results showed that 2.37% of the forest cover area is dieback canopy. The difference in the percentage of dieback forest cover between landforms was negligible. Maximum and minimum dieback areas of forest cover were in southern aspects (2.7%) and northern aspects (1.73%), slope class 0%-20% (2.6%) and more than 80% (1.52%), elevation less than 1300 m (3.36%) and more than 1700 m (0.52%), hillshade class 0-102 (2.56%) and 255-204 (0.82%), Gachsaran formation (5.08%) and Asmari-Shahbazan formation (0.96%), respectively. As a result, the amount of dieback in the southern slopes was 35.9% higher than the northern, in low hillshade was 68% more than high hillshade and in low elevations was 84.5% higher than high elevations. It seems that the higher ratio of crown dieback was occurred in the less hillshade and at low elevations, due to higher temperatures and lower soil moisture in these areas, which indicates the effective role of recent droughts in intensifying the process of forest dieback.

Water hyacinth (Eichhornia crassipes) is native to the Amazon basin and is one of the worst aquatic weeds in the world. It has been an invasive species in aquatic ecosystems of northern Iran since 2011. The use of herbicides as a method of plant control is common and efforts are made to select a formulation with the least impact on the environment. In the current study, three types of herbicide including glyphosate (Roundup), Glufosinate-ammonium (Basta) and Bispyribac sodium (Nominee) were used to control water hyacinth and the effects of their use on the abundance and diversity of planktonic communities were investigated. Roundup treatment has an immediate effect on water hyacinth, while Basta and Nominee treatments were effective for a longer period of time. Results showed that about 90% of phytoplankton and 71% of zooplankton belonged to the diatom and protozoa, respectively. The diversity of plankton species did not change after herbicides application and the number of genera in control ponds was almost constant. The phytoplankton abundance was higher after herbicides applications, especially in the Roundup treatment. The used doses of herbicides not only had a controlling effect on water hyacinth but also had no significant negative effect on the diversity and abundance of planktonic communities.

Fire ash contains essential nutrients that play an important role in the forest by changing soil properties. The goal of this study was to investigate the physical and chemical properties of ash from burning litter and branches of Aleppo oak (Quercus infectoria Oliv.). Litter and dried branches with a diameter of less than 2 and 2-5 cm were collected under the canopy of eight oak trees in Dezli, Sarvabad county, Kurdistan province. The results showed that the colors of ashes were dark gray (5Y2.5/1) in the litter and light gray(5Y6/1) in both branch treatments. The amount of K, pH and electrical conductivity increased significantly in the ashes of all three treatments compared to unburned samples, while the amount of Ca, organic carbon and total nitrogen were decreased considerably in all three treatments after burning. The amount of P in the ash of the litter increased significantly compared to the unburned litter; however, its amount decreased in both branch treatments. In general, despite the similarity of the pattern of changes in all three treatments, branch treatments showed more differences during the burning than the control, indicating a higher burning of branches compared to the litter.