IRANIAN JOURNAL OF APPLIED ECOLOGY
Year:2018 | Volume:7 | Issue:3|Papers Count:5

To study the weed population indexes of onion (Allium cepa L. ) monoculture systems in the Jiroft area, four onion continuous monocultures, including less 3 (S1), 3-5 (S2), 5-8 (S3), more than 8 (S4) years and long-term fallow (F) were sampled by systematic randomized method in three stages: before sowing, 60 days after planting and 30 days after harvest, during 2015-2016. Of the 28 weed species, 16 species were observed in all systems. The analysis of variance showed that the monoculture system had a significant effect on the density of the weed species including Cyperus rotundus, Malva neglecta, Heliotropium europium and Chenopodium murale and the density of these species were was 14. 64, 14. 16, 13. 90 and 11. 97 weeds per square meter, respectively. Increasing the in monoculture duration from three to more than eight years led to enhancing increased the density of the weed species. The assessment of the onion monoculture duration had a significant effect on the weed diversity indexes. The maximum indexes of Simpson, Shannon, Menhinick and evenness in the S4 system were 0. 92, 2. 76, 0. 90 and 0. 99, respectively, and they were the lowest in the F system (0. 78, 0. 89, 0. 78, and 0. 95, respectively). In general, the onion continuation cropping increased the weed density of each weed and significantly enhanced the species diversity indexes.

This study aimed to investigate the effects of the fire products treatments (heat, smoke and ash) on the density, species diversity, growth form and the life form of the soil seed bank in the semi-steppe rangelands of the Karsanak region in Chaharmahal and Bakhtiari Province. For this purpose, soil samples were collected from the studied region and fire products treatments were applied to them. Five treatments, including two treatments of heat shock (60 and 80 ° C), one treatment of ash (30 minutes) and control (without any treatment), were tested. Totally, seeds of 21 species from 15 plant families of the soil seed bank samples cultured in greenhouse, were germinated. The results showed that the heat treatment at 80 ° C with an average seedling number of 706 per m2 had the highest density in comparison with the control. Also, ash significantly increased the diversity and richness of the cultured samples. Most of the fire products treatments increased the share of the annual vegetative form (annual forb and annual grass). According to the results, it can be concluded that fire products effects on plant species are very important in recognizing and analyzing the responses of species in the irritability of the germinating seeds. Also, based on this information, we can predict the changes in the vegetation after the fire, which can be used in the management of natural ecosystems.

Invasive plant control is a significant challenge for natural resources management. Rosa persica (Michx ex. Juss. ) is one of the invasive species in Iran. It has been rapidly expanded to the areas where it has introduced. In the present study, we evaluated the effects of five treatments: 1) control, 2) fire, 3) cutting, 3) tilling, 4) chemical techniques (glyphsate application) in controlling the expansion of Rosa persica in a degraded rangeland plant community (Rosa persica dominant type) in Markazi province. An experiment was arranged in split plots based on a completely randomized block design with four replications for three consecutive years. We found that the combined methods have played a more effective roles in controlling the Rosa persica and among these methods; fire combined with chemical techniques appeared to be a better option for reducing the abundance of Rosa persica. Also, fire combined with the mechanical removal of the above-ground and fire combined with the mechanical removal of the root reduced population size of Rosa persica, as comapred with the control, however, no significant difference (P<0. 05) was found between the two methods. Thus, because of the disturbance in the soil, as a result of the mechanical removal of root, we recommend the use of fire combined with cutting instead of tilling to reduced Rosa persica.

Currently, there is little information on the high mountain species' response to the climate change in Iran, and it seems that these species are significantly affected by the climate change. In the current research, the spatial vulnerability of Caspian snowcock (Tetraogallus caspius) to the climate change in Chaharmahal and Bakhtiari province was predicted using the ensemble modelling approach, based on seven species distribution models. According to the findings, about 19. 43% of the province was estimated to be the suitable habitat of Caspian snowcock. The variables of annual precipitation (23. 23%), annual temperature range (21. 82%), human footprints (15. 77%) and slope (14. 46%) had the highest contributions to the model. Findings also showed that about 12. 9-32. 28% of the suitable habitats might be lost by 2050 due to the climate change, based on the two scenarios of increased greenhouse gases (RCP4. 5 and RCP8. 5) and the HadGEM2-CC model. At the same period, it is expected that the suitable habitats of the Caspian snowcock in the low altitude areas would be lost. Additionally, due to the climate change, some populations, especially in the far southern regions of the province, will undergo local extinction or may be completely isolated. Findings of this research can be, therefore, useful for adopting more appropriate approaches in order to manage and protect the Caspian snowcock populations in the country.

Habitat suitability models for the focal species are used to address the concerns related to the limited availability of data for remote habitats by scrutinizing the relationship between the biodiversity distribution patterns and the naturalanthropogenic characteristics. The current study aimed at modeling habitat suitability for seven focal species including Asian black bear, Persian leopard, Persian ibex, Wild sheep, Chinkara, Asian houbara and Mugger in the southeastern Iran, by relying on Generalized Linear Model (GLM), Generalized Boosted Model (GBM), Random Forest (RF), and Maximum Entropy (MaxEnt) models and using 10 physical, anthropogenical and land cover variables. Next, habitat suitability maps were overlaid with sensitive coastal habitats to delineate a final habitat suitability map. Based on our results, more than 34% of the region were identified as sensitive habitats which were mostly located along the coastline. These habitats demonstrated less than 15 percent spatial overlap with the current protected area network of the region. Moreover, a suitable connecting corridor extended in the east-west was identified, but it was neglected due to having lower suitability values in comparison to the central habitats and the focus of conservation objectives on the core habitat.