مجله بوم شناسی کاربردی
پیاپی 42 (زمستان 1401)

Spatiotemporal changes of net primary production (NPP) is one of the essential indicators in determining rangeland ecosystem condition. Therefore, the aim of current research was to map and monitor the actual and potential NPP of rangeland ecosystems in Kohgiluyeh and Boyer-Ahmad province, using CASA and Miami models, MODIS and field data from 2009 to 2018. The accuracy of the produced NPP maps was assessed in 253 sampling sites located in different vegetation types with good, fair and poor rangeland conditions, using linear regression. Results showed that the difference between actual and potential NPP was greater than 56 gr C/m2/month, which can be a sign of human impacts and interferences in the rangeland ecosystems of the region. The highest and lowest relationships between modeled and field productions were observed in the Astragalus spp. - Bromus tomentellus vegetation type with good rangeland condition (R2=0.84) and Astragalus sieberi- Stipa capensis vegetation type with poor rangeland condition (R2=28), respectively. The present research findings indicated the importance of drought conditions, vegetation type and rangeland condition in estimating the actual and potential NPP and the difference of these productions can be used as an index to determine and monitor the condition of rangeland ecosystems.

Human fear of large carnivores can affect human willingness to share the landscape with these species. Also, fear has the potential to influence decision-making processes and the implementation of management interventions. People who fear of large carnivores show more opposition to protect these carnivores and are more likely to support killing them. This study was conducted to investigate the factors affecting the fear of local communities toward brown bears in Kohgiluyeh and Boyer-Ahmad province. In order to find out the attitude of the local communities towards the bear, a specialized questionnaire was designed and the sample size was estimated at 332, using Cochran's formula. Social network analysis was used to assess the vulnerability of local communities towards brown bears. Based on the results, inadequate knowledge of local communities about bears leads to fear and behavioral changes, when facing this species. Efforts to reduce the human fear of bears should be focused on communication with local people. In order to reduce the conflict between human and bears, it is recommended to increase knowledge and awareness of local communities about the brown bear behavior along with other management measures.

In the current study, the environmental impacts of tomato paste production were investigated based on the total life cycle of tomato including cultivation, processing, packaging and transportation, using the Centrum voor Milieuwetenschappen Leiden Impact Assessment, (CML-IA) method in Kermanshah regions. The required information was obtained through interviews, questionnaires and, Ecoinvent, LCA Food DK and IDMAT databases. Results showed that among the influential groups, during the production process of one kg of canned tomato paste, the ozone layer depletion and the reduction of organic resources were least effected and the open waters ecotoxicity received the highest impact. In the cultivation process, electricity consumption had the greatest impact on open waters ecotoxicity followed by the nitrogen fertilizer. The factory processing phase had the lowest impact among the influential groups (except open waters ecotoxicity). The energy efficiency was calculated as 0.63 kg/MJ. The net energy gain and the total energy consumption in the tomato farm were -42700 and 44.86 MJ/ha, respectively. The consumption of electricity and chemical fertilizers were the highest amount of input energies with 75.43 and 16.94% respectively. According to the results, the cultivation phase has the adequate potential to reduce the environmental impacts during the tomato paste production through the improvement of irrigation systems to reduce electricity consumption.

Chlorophyll-a concentration is among the most important parameters used to investigate the primary production in marine ecosystems. Chlorophyll-a concentration is influenced by climatic/environmental factors, including Sea Surface Temperature (SST). Satellite sensors are able to provide reliable products of chlorophyll-a concentration and SST data with an adequate spatiotemporal resolution. In this study, level 3 (resolution 4 km) MODIS monthly products of chlorophyll-a concentration and SST  from year 2003 to 2018 of the Persian Gulf and the Oman Sea were used. The data were transformed into a raster format and the values of each pixel were extracted. Several gaps were observed in MODIS products of chlorophyll-a concentration. The Data INterpolating Empirical Orthogonal Functions (DINEOF) algorithm was used to reconstruct these gaps. Pearson correlation procedure was applied to analyze the correlation between chlorophyll-a concentration and SST. Results showed that during the study period, the correlation between the two parameters was negative (-0.44 to -0.67) and significant in the most part of the study area. The correlation coefficients in December were negative (-0.67 to -0.05) and significant in the Oman Sea and the most areas of the Persian Gulf, while in July those relationships were mostly positive (0.13 to 0.64) and significant.

Taking the advantage of the emergy approach in estimating the stability of greenhouse systems leads to the use of correct management methods to increase the stability of production in these systems. In this research, two production systems of cucumber and tomato in Sistan region were assessed, using emergy indices. For this purpose, 166 cucumber and 111 tomato greenhouses were selected. The result of measuring 13 indicators showed the relative stability of the cucumber production system to the tomato system. The highest and lowest values of transformity index in tomato and cucumber systems were 2.77×103 and 2.00×103 (solar MJ per gram), respectively. Physiological characteristics of cucumber such as longer growth period and the greater use of free renewable energies, more production and the effective use of labor, made this system more sustainable, compared to the tomato one. In the tomato production system, the high proportion of purchased non-renewable resources was responsible for unsustainability. In order to increase the sustainability in greenhouse production systems, it is necessary to select plants with a higher capacity in using free environmental energies, capability of a more efficient labor use, and to use of greenhouse structures with the technologies aimed at reducing the inputs and the purchased non-renewable inputs.

In the present study, the relationship between the distribution of Astragalus verus, climate, soil and topography in Isfahan province was investigated using the CART (Classification and Regression Trees) non-parametric regression. According to the vegetation types dominated by Astragalus verus, 287 sites were selected using stratified-random sampling and 106 presence points were recorded. Non-normally distributed soil variables were normalized according to the skewness type by data transformation. For variables that were not normalized by the data transformation, the inverse distance weighted and for normally distributed variables, kriging methods were used for mapping. To investigate the spatial continuity of these variables, the best variogram was selected. Using the principle component analysis (PCA) and correlation matrix, the most effective factors on distribution were clay percentage, mean temperature of the coldest (Bio11), and driest (Bio9) quarter, minimum temperature of the coldest month (Bio6), annual mean temperature (Bio1), saturated moisture and organic carbon, respectively. Model evaluation using replacement method and using independent data indicated high accuracy of the model. According to the optimum threshold of 0.41 and fuzzy-based habitat suitability map, the suitable habitat for the species was 34.5 % of the area. The results are used in sustainable rangeland management, conservation and their restoration.