Iranian Journal of Forests and Rangelands Protection Research
Year:2019 | Volume:17 | Issue:1 (33)|Papers Count:8

Dam construction projects can affect the functioning of the landscape by reducing the integrity and increasing distruption, and consequently, this change in the landscape could affect the function of the environment. Quantifying landscape changes is performed using landscape metrics and their variety makes them to be widely used in ecological studies and solving environmental problems. The purpose of this research was to investigate the trend of structural changes in forest cover in Shafarood watershed due to the construction of Shafarood dam. To ths end, three Landsat satellite images were used during the peak season of vegetation cover in 2000, 2013 and 2017. Geometric and atmospheric corrections were applied to these images. Using the maximum probabilistic classification method, the land use maps of the area for each year were prepared. Land cover maps had overall accuracy and Kappa coefficient higher than 86% and 83%, respectively. The results indicated an increase in the fragmentation and destruction of habitat conditions in the Hirkani forests and an extensive replacement of forest cover with no vegetation areas. The results also showed that the decline in the number of forest patches between 2013 and 2017 caused short-term centralized demolition at the project site, while the construction of dam and related facilities, such as roads and lateral installations have not yet been completed. To protect natural resources, the development process should be coordinated with the constraints and capabilities of the ecosystem through precise environmental studies, the assessment and explanation of the environmental impacts of the projects on the environment, and the presentation of approaches for reducing and mitigation of the destructive effects of development projects.

Severe drought stress restricts the growth of plant species such as oak trees and at the onset of weakness, invasion of pests and diseases and ultimately death is inevitable. The use of rainfall storage techniques provides the water needed for plant growth in the soil. This study aimed to examine the possibility of using two small water catchment (Linear terrace and Crescent pond), to cope with the critical conditions of oak forests, located in Chavar section of Ilam province; comparing to the control (without storage) in a randomized complete block design. Before running the storage systems, trees characteristics, as well as soil and moisture content were measured and during the 4-year period, monthly soil moisture and health status of the trees were recorded. Experimental results showed that soil moisture decreased in proportion to the amount of rainfall in the low season, so that in hot months, the moisture loss crisis reaches even more than one meter deep. Comparison of mean soil moisture changes showed significant effect of rain storage methods on soil moisture content by 21% in linear banquet method and 39% in crescent banquet method. Evaluation of the degree of vitality and health of the trees showed that there was a significant difference between the treatment of rainfed storage and the control treatment at 95% confidence level, indicating the positive effect of the rainfed storage on the health of the trees. Therefore, the use of water catchment systems to store the precipitation is recommended to increase soil moisture and improve the health and vitality of the declined trees.

Plasjan sub-basin is located in the west of Gavkhoni basin between Isfahan and Chaharmahal-Bakhtiari provinces and has forest zones. Forest ecosystem has important roles such as runoff controlling, ecotourism and preparing wildlife habitat. Therefore, determination of land capability is essential for forest conservation, restoration and development through modeling of land forestry capability. To achieve this goal and to reduce the uncertainty in model preparation, a combination of multi-criteria evaluation and fuzzy analytical hierarchy process method was used. The criteria were determined according to the experts and reviewing the references, their weights were calculated using fuzzy analytical hierarchy process, the criteria and sub-criteria were standardized applying fuzzy and constraints by Boolean methods. The data layers were combined using a weighted linear combination model and a reclassification map was prepared to develop the land forestry capability model. Survey of the produced maps showed that areas with high potential for forestry activities were 9. 6% of the total area and in accordance with the current distribution of forests which due to the appropriateness of evaluation criteria, were located in southwestern areas. The results of this study revealed that although the WLC method with high trade-off level was used, due to the relative limitation of some criteria such as high lime content, high slope and elevation and low temperature in some areas, 77 % of the Plasjan area is moderately and less suitable for forestry activities.

Khuzestan province accounts as the most important natural habitats for Euphrates poplar (Populus euphratica Olive) in Iran. During 2008– 2011, the harmful & benefical arthropods fauna associated with Euphrates poplar were studied in three selected sites of natural stands of Khuzestan province. The studies carried out every 15-30 days during the growing seasons of the host plant. Samples were mainly collected by Schneider trap, direct hand, collecting of infected tree branches, as well as rearing immature instars of the pests on seedlings in controlled conditions. Cooperation of various senior experts inside and outside of the country was used to assist recognizing insect species. A total of 23 pest species belonging to 16 families of 5 orders and also, 12 species of predatory arthropods belonging to 7 families of 5 orders were collected and identified as follows. Among the introduced pests, 11 species were more important in terms of contamination and damage, among which 8 species were common in the three studied habitats. A number of species were mainly collected for the first time from the mentioned localities. Gypsonoma euphraticana Aims., Gypsonoma spp., Lithocolletis sp., Phyllocnistis sp., Cerura vinula L., Harpyia leucotera Stichel, Egeirotrioza intermedia Baeva, Egeirotrioza ceardi (Bergevin), Egeirotrioza sp., Syntomoza unicolor (Loginova & Parfentiev), Chaitophorus euphraticus Hodjat, Pachypappa sp., Salicicola kermanensis Lndgr., Diaspidiotus slavonicus (Green), Ceroplastes rusci (Linnaeus), Monosteira unicostata (Muls. & Rey), Apodiphus amygdali Germar, Tetranychus urticae Koch, Melanophyla picta Pall., Capnodis miliaris Klug, Microcerotermes buettikeri Chhotani& Bose, Microcerotermes diversus Silvestri, Anacanthotermes vagans (Hagen). Coccinella undecimpunctata L., Coccinella septempunctata L., Chilochorus bipustulatus L., Scymnus sp., Orius laticollis (Reuter), Anthocoris sp., Deraeocoris (Phaeocapsus) pilipes (Reuter), Deraeocoris sp., Chrysoperla carnea Steph., Anystis baccarum (Linn), Xysticus sp., Cheiranthium sp.

The oak trees decline in Zagros forests is one of the main problems of the ecosystem of this region. Therefore, in this research, estimation and prediction of oak forests decline in the middle Zagros (Lorestan section) were performed to evaluate the RS data and decline indices including DVI, GEMI, IPVI, MSAVI2, NDVI, EVI, OSAVI, Sarvi2, SR and VHI. To this end, these indices were extracted using ArcGIS for 110 sites of oak forests. Finally, a matrix of 345 × 110 dimensions during 2001 to 2016 was created. Then, fuzzy and neural network methods were used in the prediction strategy, and the method with less error was considered as the prediction basis for the period 2017-2030. The cluster analysis and the discriminant analysis were also used to identify the decline areas, and spectral analysis was used to investigate the oscillation. The results showed that the decline indices had an increasing trend in the most cases. The results of cluster analysis also revealed that oak forest decline can be divided into four areas (no decline, normal decline, high decline and very high decline areas). Investigating the fluctuations of the dominant areas also indicated short-term cycles of 2 to 4 years fluctuations on drying indices. Neural network evaluation and fuzzy method also demonstrated that neural network method is a more suitable method for predicting decline indices. The prediction results indicated that in the future, most of the decline indices in the region will be increased.

This study was intended to identify seed feeding insects and to investigate their biodiversity on Fabaceae rangeland plants in North Khorasan during 2015-2016. Therefore, sampling was carried out with collecting legum seeds as weekly from April to September each year and biodiversity indices were calculated using SDR software. In this study, 25 seed feeding insects were identified that belonged to the Hymenoptera, Coleoptera, Lepidoptera and Heteroptera orders. Among 4421 seed feeding insects, the highest numbers belonged to Astragalus suluklensis Frey& Sint with 593 specimens (10 species), A. macropelantus Boiss with 303 (7 species) and A. iranicus Bung with 513 (4 Species), respectively. Species of Bruchophagus mutabilis Nikolskaya, 1952; B. astragalus Fedoseev, 1954; and Bruchidius virgatus Fahraeus, 1839; were the most abundant among seed feeding insects with relative abundance od 35. 35, 9. 58 and 7. 05 percent, respectively. The diversity index indicated that Sissab area and Sargil protected park, had the highest diversity among diverse species and Jajarm and Golestan National Park were the least diverse species. On the other hand, the altitudes of 1200 to 1800 meters had more diversity than other elevations. Among the seed feeding insects, B. mutabilis and B. astragali, with 80% damage, B. dahuricus Zerova with 45% damage, Bruchidus virgatus, Fahraeus, B. lukjanovistsci B. lukjanovistsci (Ter-Minassian, 1969) and B. astragali (Boheman, 1829) with up to 60% of damage and Etiella zinckenella Treitschke with up to 90% damage have been identified as the most destructive insect pests.

Hemocytes as the immune system are important factors against fungi, bacteria and insecticide particles. Studying the morphology of hemocytes and their frequency is essential as the first stage in identification of cellular immune characteristics. In the present research, the types of hemocytes were investigated in the haemolymph of Osphranteria coerulescense and Zeuzera pyrina larvae after staining with Giemsa and by light microscopy at 40x magnification. Four types of hemocytes including prohemocytes, plasmotocytes, granulocytes and oenocytoides were identified in hemolymph of both pests. Spherulocytes and podocytes were observed only in hemolymph of Z. pyrina and 2nd and 3rd instars larvae of Osphranteria coerulescense, respectively. Prohemocytes as stem cells were small and often round with central nucleus. Plasmotocytes had often polymorphism profile and together with granulocytes were the most abundant hemocytes in both insects. Granulocytes are variable in size, round or oval shape with large nucleus in relation to cell size. They were the most abundant cells in the hemolymph of 4th and 5th instars of Zeuzera pyrina. Oenocytoid were also found to be generally small to medium-sized, oval shape with round and eccentrical nucleus. Spherulocytes were usually rounded or elongated cells and larger than Granulocytes. The total hemocytes count at different larval stages of both insects showed that the number of cells was directly related to larval age. The total number of cells was higher in the 3rd instar larvae of O. coerulescence and 5th instar larvae of Z. pyrina in comparison to the other instars. Differential hemocyte count showed that frequency of Plasmotocytes and Granulocytes were the highest in all of larval instars. The present study provides detailed information of hemocyte profile and hemogram of two wood boring insects. These findings could be used as a basis for further investigation on the immunology studies of Osphranteria coerulescense and Zeuzera pyrina.

The Zagros Woodland is one of the main components of Zagros ecosystem that has significant role in water and soil conservation. Drought, as one of the climatic hazards, can have dramatic effects on forest cover. Therefore, detecting the spatiotemporal dynamics of the forest in response to drought is very important. The main objective of this study was to detect the spatiotemporal relationship of forest cover of Lorestan province in response to annual drought. In this regard, the Enhanced Vegetation Index (EVI) values were extracted from Landsat 5 and 8 images for the period 2017-2017. The Standardized Precipitation Index (SPI) was calculated for the mentioned period using monthly rainfall statistics of 9 synoptic stations in the region. By using spatial correlation analysis, the relationship between annual forest area and drought index was investigated and finally, sensitivity function of spatial variation of forest cover was obtained by fitting a linear model. The results of field sampling showed that EVI threshold> 0. 4 can be considered as the province's forest cover threshold. Correlation analysis between forest cover and drought indicated that the 18-year time series of forest cover had a significant correalation of 0. 68 with SPI (0. 95 confidence level). The results of development of sensitivity function to SPI index indicated that the forest cover had significant sensitivity to drought so that for each 0. 1 unit change in the SPI index the forest cover area will change as 14880 ha in the same direction.