Nechisar park gis based conservation assesment
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ANALYSIS OF LAND AND VEGETATION COVER DYNAMICS USING REMOTE SENSING & GIS TECHINIQUES,A CASE STUDY OF NECHISAR NATIONAL PARK Abstract The research aims to analyze the trend of land and vegetation cover dynamics over the period from 1976, 1986 2000 and 2007 thus examine the conservation status of the area and generate up-to-date land cover map. Information is extracted from various Satellite images of multidated Landsat, ASTER and MODIS images. The Landsat images are the basic remote sensing data to generate the thematic maps which are further analyzed to show the cover dynamics in the park for 24years. All datas from the satellite images are processesed and analyzed using digital image processing techniques. Besides, different vector data are extracted from the images as well as other thematic maps. MODIS-NDVI images are analyzed for the different land cover classes and each vegetation cover seasonal response is compared for the year 2000 and 2005. The land cover classes identified in the study area from 1976, 1986, 2000 and 2007 are water body, riparian and ground water (GW) forest, wood land, dense bush land, bushy shrubbed grass land, open grass land, degraded grass land, cultivated land, swamp vegetation and bare land. Rate of land cover change and fragmentation of habitat were discussed for the different land cover classes. Rate of land cover change, fragmentation index and land cover conversion matrix clearly shows the dynamics of the different cover classes has happened for the past decades and generally the park conservation status is found to be poor. Bush encroachment in the study area is a major challenge to the park particularly for the grass land and overgrazing on the Nechisar plain has caused expansion of invasive plants erosion and land degradation. The community livelihood dependency both in the rural and urban setting is concluded and discussed as a challenge to the park from biodiversity conservation point of view. Key Words: Land cover dynamics, National park, Vegetation cover, Remote sensing and GIS, Habitat fragmentation, degradation, biodiversity conservation.
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Nechisar park gis based conservation assesment
- 2. 1.Introduction • deforestation, grazing cattle, human habitation and over fishing in the park have caused severe stresses and degradation of park ecosystems, leaving the sustainability of NSNP resources in question. (Alison M. Jones, 2005) • The park had been excessively encroached by invasive plant species and the small but rare groundwater forest had been subjected to unsustainable illegal harvesting (Report of African Parks foundation, 2005) 1.1.Statement of the problem
- 3. Freeman(2006) Natural Resource Challenges of NSNP NSNP Forest Springs Wild Animals (land-based) Grass land Wild animals (lake-based) Fish Swamp,Sokke Grazing land Cut for firewood Habitat being destroyed over-grazing Nowhere for towns people to graze cattle Being over-cut Depleted by over-fishing Fish breeding area destroyed Risk to numbers caused by lack of fish Potential use by investors Unknown impact on forest Unknown impact on lake and resources Farming land Land degraded
- 4. 1.2.Objectives of the study 1.2.1 General objective : to analyze the trend of land and vegetation cover dynamics for the period starting from 1976-2007 thus to assess and examine the conservation status of the area and generate up-to- date land cover map
- 5. • To assess the trends of land and vegetation cover dynamics in the study area during the period from 1976, 1986 and 2000, • To generate up to date land cover map for the year 2007, • Studying the conservation status of NSNP focusing on invasive plants encroachment and land degradation, • To show the annual biomass growth response, 1.2.2.Specific objective
- 6. 2.Description of the study area 2.1. Location •Located in Africa’s Great Rift Valley, 575km southwest of Addis Ababa, • Diverse Habitat -Open grass land -Ground water & riparian vegetation -Lake shores -Dense Bush land -Acacia woodland
- 7. 2.2 Climate According to Ethiopian climate classification -NSNP is classified in Hot Semi arid tropical climate Arbaminch Meteorological Station 60 04’N 37036’E, 1300 m a.s.l Dry season Wet season
- 8. 2.3 Biodiversity : Flora and Fauna Vegetation diversity GW & riparian vegetation Ficus sycamorus , Cordia africana, Teclea nobilis Open grass land Savanna grass types Acacia wood land Acacia mellifera, Acacia tortilis, Rhus natalensis Steep & hill vegtn(1300-1650m) Combretum molle, Euclia divinorum Dodonea angustifolia High elevation vegetn(>1650m) Myrisine Africana, Erythrina brucei, Arundinaria alpina Lake shore vegetn Typha domingensis Saccharum spotaneum Sesbania sesban
- 9. Rich fauna diversity and next to Mago national park in mammalian diversity
- 10. 2.4 Topography and Hydrology Nechisar plains are bounded by:North lake Abaya ,South and southwest lake Chamo Abaya receives 86.484mm3 of discharge annually, while lake Chamo receives only 29.250mm3 Kulfo –flows from North of Arebamench & runoff joins lake shores of Chamo- Irrigation at chamoleto Arebamench(Traditionaly 40 springs)-GWF Seremele- perennial & runs along the eastern most cultivated fertile flood plains,
- 11. 2.5 Socioeconomic Rural:Weredas adjacent to the national park livelihood are farming, fishing, Tourism & petty trade Communities inside the park Kore-Live in Amaro Mountains & cultivate the Sermele floodplain Guji- are nomadic pastoralists grazing approximately 4000 – 5000 heads of stock in the park Urban :Arebaminch 168,172ha estimated area,Population 232,000 with 50.8% male and 49.2% female proportion (SNV,2006). Livelihood: Farming crops:maize, sorghum, Fruits:bananas , mangos ,apples and pears,FishingFishing --TourismTourism service (hotels and tour operators), Trade ,Employment
- 12. 3.Materials and Methods • Software & program :ArcGIS 9.2, ERDAS Imagine 9.1, Map source, • GPS-receiver (Garmin), • Digital Camera, • Topo map of the study area (1:50,000 scale) • Multi dated Satellite images (Landsat images 1976-MSS,1986-TM and 2000-ETM+, 2006- ASTER) • MODIS NDVI-image(2000&2005) • SRTM (90m contour interval) 3.1.Materials
- 13. Landsat MSS (1976) Landsat ETM+ (2000) Landsat TM (1986) Image processing (Remote sensing techniques) Image rectification Image enhancement Image classification Unsupervised Supervised Image interpretation Accuracy assessment ASTER image 2006 -Topo map (1:50,000) -Secondary data and previous land use/cover maps, -Google Earth image, KML files -SRTM -Field ground verification -Senior park staff and Scout interview -Community discussion -Workshop proceedings Out puts Land cover change comparison thematic maps Up-to-date land cover map of NSNP Statistical results of cover change dynamics(charts, graphs, index values) Impacts of the cover dynamics and the conservation status of the national park GIS data integration and statistical analysis -Cover change comparison -Land Cover change rate & Conversion matrix -NDVI Seasonal vegetation cover response -Landscape fragmentation index MODIS-NDVI Images for 2000 and 2005 3.2.Methodology
- 14. 1. Identifying Land use/cover data sources Bolton(1970) distribution of main land cover types Topo map,1979-1985 FAO/UNDP(1992), RVLB LU/LC map, Assistance to land use planning project 2.Sattelite image visual interpretation (TCC/FCC Band combination, select training site pixels, Google earth image KML files, field inventory) 3.Unsupervised & Supervised cover classification and accuracy assessment 4. Land cover classification and result interpretation, statistical analysis (cover change rate, conversion matrix, fragmentation index) 3.2.1.Data analysis and Organization
- 15. 4.Results and Discussion -Unsupervised classes of Landsat 2000 gives the classes which are verified at field -10 major land cover classes are identified and training classes are set for each year satellite image -Accuracy assessment for each year cover map conducted 4.1.Unsupervised classification and select basic land cover units
- 16. Land and vegetation cover classes identified in NSNP for this study REPARIAN & GW FOREST1 ACACIA WOOD LAND2 BUSHY SHRUBBED GRASSLAND3 OPEN GRASS LAND4
- 17. BARE BUSHED GRASSLAND5 CULTIVATED LAND6 SWAMP VEGETATION7 DENSE BUSH LAND8
- 18. BARE LAND & EROSION10 WATER BODY9
- 19. 4.2.Land Cover classification thematic maps 1% 4% 2% 25% 11% 11% 11% 6% 30% Riparian and GW forest Wood land Dense bush land Bushy shrubbed grass land Open grass land Open bushed grass land Cultivated land Swamp vegetation Water body 2% 26% 1% 10% 13% 31% 7% 6% 4% Riparian and GW forest Wood land Dense bush land Bushy shrubbed grass land Open grass land Open bushed grass land Cultivated land Swamp vegetation Water body
- 20. 1% 5% 12% 14% 12% 14% 6% 6% 30% Riparian and GW forest Wood land Dense bush land Bushy shrubbed grass land Open grass land Open bushed grass land Cultivated land Swamp vegetation Water body 2% 26% 1% 10% 13% 31% 7% 6% 4% Riparian and GW forest Wood land Dense bush land Bushy shrubbed grass land Open grass land Open bushed grass land Cultivated land Swamp vegetation Water body
- 21. Land cover classes for 2007 4798, 10% 1819, 4% 3231, 7% 10124, 21% 7610, 16% 3549, 7% 2532, 5% 14531, 30% Riparian and GW forest Wood land Dense bush land Bushy shrubbed grass land Open grass land Degraded grass land Cultivated land, Swamp and bare Water body Accuracy assessment The final up to date cover map is generated using the information of past classification , field inventory and accurate training selection GCP were used to validate the Landsat and ASTER image classification accuracy assessment and the error matrix gives average results: 78% accurate for 1976 Landsat-MSS image, 80% accurate for 1986 Landsat-TM image, 72.22% accurate for 2000 Landsat- ETM+ image and 95% accurate for 2007 Land cover map using ASTER image Up- to date Land cover map & Classification Accuracy assessment
- 22. 1.Cover change comparison for 1976,1986 ,2000 Land cover comparison 0 2000 4000 6000 8000 10000 12000 14000 16000 1 2 3 years(1-1976,2-1986,3-2000) Area(ha) Riparianand GW forest Wooded grass land Dense bushland Bushyshrubed grass land Opengrass land Openbushed grass land Cultivated land Swamp vegetation Waterbody Uneven distribution of land cover class for the spatial and temporal dynamics in the past 24 years From 1976 to 1986, -a total loss of grassland 562.6ha/year -Bushy shrubbed grass land has increased at a rate of 714.1ha/year, From 1986-2000 -a drastic loss of the swamp vegetation at a rate of 92ha/year -Riparian and GW forest have shrunk at a rate of 3.34ha/year -cultivated land expand during the two periods at a rate of 1.12ha/year and 12ha/year
- 23. Cover change comparison for 1976,1986 ,2000 & 2007 Land cover class comparison 0 2000 4000 6000 8000 10000 12000 14000 16000 RiparianandGW forest Woodland Densebushland Bushyshrubbed grassland Opengrassland Barebushed grassland Cultivated,Swamp andbareland Waterbody Land cover class Area(Ha) 1976 1986 2000 2007 -Progress in the Riparian & GW forest, Open grass land,Bushhy shrubbed grass land - Cover decline in cultivated land ,Bare bush grass land, Wood land, Dense bush land -Water body is constant and spatial changes are insignificant
- 24. 2.Rate of Land cover change +6.56 -46.95 +82.5 +197.25 -265.7 +122.05 +25.35 -147.95 -7.025 Net change rate 121.12Water body -92-1.9Swamp vegetation 12144Cultivated land 54.78394.5Bare bushed grass land 31.2-562.6Open grass land -470714.1Bushy shrubbed grass land 275-224.3Dense bush land 129-424.9Wood land -60.8546.8Riparian and GW forest 1986-20001976 - 1986Land cover class Rate of land cover change (ha/year) 0 2000 4000 6000 8000 10000 12000 14000 16000 0 2000 4000 6000 8000 10000 12000 14000 16000 Series2 1986 3559.2 1104.58 2873.42 12367.7 6328.4 4881.3 721.197 1892.22 14553.1 Series3 2000 2707.96 2910.78 6726.57 5787.85 6765.12 5648.31 2417.42 595.298 14723.7 Series1 1976 3091.1 5354.35 5116.53 5226.02 11954.4 936.037 280.389 1911.06 14541.9 Cover classificati on Riparian and GW forest Wooded grass land Dense bush land Bushy shrubed grass land Open grass land Open bushed grass land Cultivated land Swamp vegetation Water body Area(ha)
- 25. 3.Land cover change Conversion matrix Conversion Matrix for 1976 and 1986 0 1000 2000 3000 4000 5000 6000 R iparian and G W forest W ood land D ense bush land Bushy shrubed grass land O pen grass land Bare bushed grass land C ultivated land Swam p vegetation W aterbody Land cover types Area(ha) Riparian and GW forest Wood land Dense bush land Bushy shrubed GL Open grass land Bare bushed GL Cultivated land Swamp vegetation Water body Conversion matrix for 1986 and 2000 0 1000 2000 3000 4000 5000 6000 R iparian and G W forest w ood land D ense bush land Bushy shrubed grass land O pen grass land Bare bushed grass land C ultivated land Swam p vegetation W aterbody Land cover class Area(ha) Riparian and GW forest Wood land Dense bush land Bushy shrubed GL Open grass land Bare bushed GL Cultivated land Swamp vegetation Water body 1976 to 1986 Most covers are converted dominantly: to dense bush land, bare bushy grass land cultivated land and Bushy shrubbed grass land 1986 to 2000 Open grass land ,swamp vegetation and Riparian vegetation taken by mainly Bushy shrubbed grass land and Bare bushed grass land
- 26. 4.Landscape fragmentation 368036373635Water body9 182423Swampy vegetation8 134846Cultivated and bare land7 226440Bare bushed grass land6 60253341Open grass land5 2111969Bushy shrubbed grass land4 333434Dense Bush land3 223555Wood land2 79147134Riparian and GW forest1 Pa value for 2000 Pa value for 1986Pa value for 1976 Land cover classesNo The park habitat is highly treated and most cover classes have shown a fragmentation index value that describes the NSNP is highly disturbed Fragmentation of ecosystems into small patches can reduce habitat for wildlife species that require larger, connected patches and introduce predators, parasites, and competitors (Core national indicator, 2000)
- 27. TRRM rain fall data (2000-2006) GW & Riparian Grass land Bare land Water body Wood land Swamp veget Bush land High Biomas growth -April,May ,October & November Less biomas growth -January to march,June to september and december 4.3.MODIS NDVI Image analysis-to see the temporal biomass growth Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 0 50 100 150 200 250 300 RainfallinNechSarNP(mm) 2000 2001 2002 2003 2004 2005 2006 Average 2005 NDVI profiles 2000 NDVI profiles
- 28. 4.4.NSNP natural resource challenges and conservation status Though natural processes contribute to change in land cover, the major driving force is human induced land uses (Allen and Barnes, 1985) Major ecological challenge faced in the NSNP due to anthropogenic and natural factors the surrounding population is currently growing rapidly, consequently inducing high pressure on the resource base of NSNP Different studies show Cattle grazing in the Nechisar plain, poaching of wildlife, illegal fishing and felling of timber from the groundwater forest, farming at Kulfo and Seremele valley encapsulate the main problems Socio-economic setting are influenced by the existing environmental conditions and Political unrest during the early 1990s led to intense damages in a relatively short period of time Natural challenges includes Bush encroachment, invasive plant expansion
- 29. Riparian and GW forest situation Progress in forest cover Total cover in the year 2007 4798ha which is highest compared to previous classes Supportive measures -The forest Guarding strategy implemented by APF-Ethiopia -Restoration of cultivated areas at Chamo letto & Seremele riparian vegetation -Future afforestation programs which will be implemented for Arebaminch town wood supply - Alternative energy option project -Community participation for park resource management Control forest degradation Sermele forsest restoration Chamoletto forest degradation
- 30. Open Grass land situation Challenges The GL is degraded heavily where livestock density is high,Land degradation & erosion are seen at overgraze plain -Malvaceae family Invasive plant(Abutilon bidentatum ) and Bush encroachment (mainly Dichrostachys cinerea, Acacia mellifera and Acacia oerfeta) Supportive measures -17 hectares of GL were cleared of invasive plant species (APF,2005) -In 2007 Open GL covers 16% of the total area, higher than the 1986 and 2000 GL spatial cover
- 31. 31 ? ? ?
- 32. 5.Conclusion and Recommendation In the past three decades as the population around Nechisar National Park and nearby Arba Minch increases, so do the Pressure to the park natural resource such as grazing cattle at Nechisar plain, farming expansion,etc The results of the thematic maps for land cover classes of 1976, 1986, 2000 and 2007 shows uneven dynamism for the different land cover classes except the changes for the water body is relatively insignificant or uniform There is a tremendous land cover change in the open grass land cover as compared to other cover classes and it’s calculated a total loss of grassland, 562.6ha/year over the 10years of 1976-1986 Bushy shrubbed grass land has increased highly for the first 10 years period from 1976-1986 at a rate of 714.1ha/year, and second period from 1986-2000 by 470ha/year.
- 33. Habitat fragmentation is also a serious challenge in the park for the different land and vegetation cover classes as the broken patches of land cover results a fragmented landscape which is unhealthy for the ecosystem functioning. Remote sensing and GIS to study Land cover dynamics could facilitate for a proactive planning process that enhances the implementation of sustainable natural resource management for decision makers, park managers and other stakeholders.
- 34. Recommendation • The Nechisar plain is severely affected by environmental and anthropogenic challenges thus needs priorities to completely stop Farming, overgrazing and plan appropriate bush encroachment controlling strategy. • The dependency of the surrounding community to the natural resources of the park has to be a priority agenda and for successful and win-win solution there should be the integration of different actors to start participatory park management and ecotourism projects • The ground water forest which is unique habitat for the country has to be protected from any exploitation and investment projects such as water bottling industries which are already proposed by investors and this should be discouraged unless detailed impact assessment is conducted.
- 35. The situation in the park has shown improvement once APC Ethiopia is taking the responsibility to manage the national park, to realize the vision of APC & to set the Nechisar national park a model to other treated parks in the country all actors participation is important Due to current situation there should be a quick response for a wise decision before the park resource is aggressively devastated while conflicts among the surrounding communities arise during transitional periods between APC–Ethiopia, Regional Governments and the Federal Government. Finally I recommend for further researchers to study the impact of vegetation cover dynamics on the situation of endangered wild life such as Swayenes heartbeets and to conduct a scenario analysis on the relationships of natural resource degradation and wildlife extinction.
- 36. Thank you! Lets be responsible for the only Nature!
- 37. Acknowledgement • My supervisor Prof. Zerihun Woldu • HoARENC • AAU Earth science department • AAU Biology department,Herbarium center • African Parks Foundation (APC p.l.c –NSNP) • GO’s and NGO’s • Friends • Family