Facts about Rangelands

Transcription

1 Facts about Rangelands Rangelands occupy the largest area under one type of land use in the non tropical dry areas. They are complex ecosystems (influenced by geology, gy climate, as well as current and historic management). Local topographic features such as slope and aspect play a crucial role in a number of morphological, ecological, and hydrological processes. They contribute to the living of the poorest populations. However, e,the rangeland gea daeas area is decreasing, eas the capacity of rangelands to produce products and perform functions is declining, and their biodiversity is threatened due to a combination of environmental and human induced factors. 1

2 Causes of Rangeland Degradation Disruption of traditional grazing system Encroachment of agricultural practices into traditional rangeland areas Improper grazing practices (overgrazing and early grazing) Lack of grazing policies The destruction of woody plant species by burning them as fuel Peganum harmala 2

3 Soil Erosion? 3

4 Tajikistan Oqjar Site South Facing North Facing Tajikistan Oqjar site South Facing North Facing 4

5 Elevation (meters) = height above mean sea level Slope (degrees) = maximum rate of change in z value Aspect (degrees) = direction of maximum rate of change in z value from each cell (e.g. slope direction) Study Objective This primary objective of this study was to examine the influence of geo morphological l landscape patterns on vegetation characteristics across central Asia 5

6 Countries (sites) Material & Methods Tajikistan (Oqjar & Karsang) Kyrgyzstan (Jelargi 1 & 2) Timing Spring & autumn Aspect North & South facing slopes Experimental Design The data collection took place during the winter and summer of 2009 in Kyrgyzstan and Tajikistan. The treatments included: location (site), season (spring and winterpastures), and transects. An ANOVA using replicated trials in incomplete block designs was used to determine the relationship between aspect and vegetation characteristics. Treatment included location (site), season (winter and summer pastures), and transects. In another word, we performed pair wise comparisons to assess treatment effects on the response variable 6

7 Data Collection/Variables Line Intercept Technique Data Collection/Variables Biomass (DM g/m 2 ) 7

8 Data Collection/Variables Digital Vegetation Charting Technique Image Processing Digital Charting Technique 8

9 Digital Charting Technique Cenchrus ciliaris 9

10 Preliminary Results Percent Green Vegetation based on LIT (point sampling) Tajikistan Kyrgystan <.001 North South <

11 1. Percent Green Vegetation based on LIT (point sampling) ANOVA Output Source of variation P-value Country <.001 Site Aspect <.001 Transect Country x Aspect <.001 Site x Aspect Country x Transect 0.82 Site x Season < Percent Bareground based on LIT (point sampling) Karsang Oqjar Jelargi 1 Jelargi 2 Tajikistan Kyrgystan <.001 <.001 North South 11

12 2. Percent Litter & Rock based on LIT (point sampling) Litter Rock North South North South < Biomass Production (DM g/m 2 ) based on quadrat sampling Karsang Oqjar Jelargi 1 Jelargi 2 Tajikistan Kyrgystan 12

13 3. Biomass Production (DM g/m 2 ) based on quadrat sampling North South Spring Fall 4. Dominant species Tajikistan Dominant Species Site North Facing South Facing Oqjar Malcolmia turkestanica Astragalus rytlobus Karsang Cynodon dactylon Cynodon dactylon Avena trichophora 13

14 5. Percent Green Vegetation based on DVCT (image processing) 5. Percent Green Vegetation based on DVCT (image processing) 14

15 5. Percent Green Vegetation based on DVCT (image processing) North Facing Tajikistan Oqjar site South Facing Average Green Cover (%) Average White % Average Bareground (%) Average Black % Minimum GC % Minimum White % Minimum BG % Minimum Black % Maximum GC % Maximum White % Maximum BG % Maximum Black % Standard Deviation Standard Deviation # of Images 14 # of Images 40 Capacity Building 15

16 Capacity Building Conclusions Site, season and aspects have significant impact on the vegetation characteristics (specie composition, cover, and biomass production) Using modern technology for assessing and monitoring rangeland conditions is advantageous: Objective Save time and money Non destructive and repeatable over time 16

17 Management Implications The present study emphasizes the strong relationship between vegetation coverage and surface temperature (potential direct incident radiation) When considering rehabilitation options Species choice (drought tolerant) Grazing management Timing (season), duration, stocking intensity 17