Microclimate Changes of Cushion Species OnobrychisCornuta Affected by Fire in Golestan National Park Grasslands

Cushions as dominant species of mountainous habitats facilitate surrounding species. The aim of this study is the investigation of fire on OnobrychisCornutamicrohabitats in the mountainous grasslands. Fire occurredin summer 2013. Therefore, in order to study the temperature fluctuations, thermometers were established under burned and unburned patches since 15 March 2016 for 31 days (half hours intervals). Parameters related to temperature were recorded with iButton thermometers and then were compared usingt-test between control and burned shrubs in two time intervals. Except for the min temperature, other parameters related to soil temperatures including max, DTF and mean temperatures significantly increased (P≥0.01). DTF in burned patches (2.5-14.5 ºC) was higher than control shrubs (1.0-3.5 ºC). Soil moisture was also measured by TDR instrument in the both burned and unburned shrubs during two time intervals. For determination of the most important factors affecting soil moisture including fire, time and their interactions, GLMM were applied and compare mean were tested by T-test. Considering GLMM results, time (F= 22.4; P ≤ 0.01) had highest impact on soil moisture. Soil moisture in both control and burned sites declined which was only significant at the first sampling time (P≥0.05).