GIS-BASED CROP SUITABILITY AND CLIMATE CHANGE VULNERABILITY OF FARMING SYSTEMS IN CAGAYAN VALLEY

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1 GIS-BASED CROP AND CLIMATE CHANGE VULNERABILITY OF FARMING SYSTEMS IN CAGAYAN VALLEY Januel P. Floresca 1 1 Isabela State University, Echague, Isabela, 3309, Philippines januelpf@yahoo.com.ph KEY WORDS: GIS-based crop suitability analysis, climate change vulnerability, farming systems ABSTRACT: Geographic information system (GIS) is a tool capable of facilitating assessment of vulnerability to the impacts of climate change of farming systems and analyzing crop suitability of crops for agroforestry establishment to enhance the resiliency of existing farming systems. The study was aimed to assess the vulnerability of existing rice and corn farming systems to the impacts of climate variability and extremes and to assess the suitability of tropical fruits to be introduced for the establishment of agroforestry farming systems using GIS. The weighted rating model (equal weights) was used in overlaying thematic maps following the IPCC framework that vulnerability is a function of exposure, sensitivity and adaptive capacity. Results indicated Echague, Isabela had the highest land area with high vulnerability of 99, ha, followed by Penablanca with 22, ha, then by Maddela with 7, ha and Bagabag as the lowest with only ha. For the four study sites, most of the land area had low vulnerability with 298, ha, followed by moderately vulnerable with 176, ha while the lowest was highly vulnerable with 130, ha. Babaran, Echague, Isabela had the highest climate change vulnerability index considering that the main crop is only corn exposed to more frequent typhoons and drought. Results also indicated that all the tropical fruits (rambutan, Mango, lanzones, pummelo) and bamboo were suitable to be planted in all the municipal study sites and selected model farms based on the ecological requirements of each. Tropical fruits and bamboo are suitable in climate change-vulnerable areas in Cagayan Valley. The GIS climate change vulnerability maps should be disseminated to LGUs and vulnerable communities to enhance their awareness and utilize the information for planning and decision-making on climate change-resilient farming system development. 1. INTRODUCTION The Cagayan Valley Region (where the Cagayan River, the longest river in the country of approximately 490 km long is located) is geographically positioned adjacent the Pacific Ocean that made it exposed to the wide area climate variability and extremes such as intensified and more frequent tropical cyclones, monsoon rains as well as the El Niño-La Niña Southern Oscillation (ENSO) oceanic phenomenon that cause floods, flashfloods and landslides/soil erosion, and droughts. Cagayan Valley is considered as one of the most vulnerable regions to climate variability and extremes particularly typhoons and floods in the Philippines based on the collaborative action research titled Enhancing the climate change adaptive capacities of LGUs and Scientists in the Philippines conducted by CPAF-UPLB with ISU as their research partner. Results confirmed high degree of adverse impacts of typhoons and monsoon rains on flooding affecting smallholder rice and corn farmers. The identification of the areas most vulnerable to climate change risks in the Country is among the most urgent of policy needs based on the National Framework Strategy on Climate Change (NFSCC) formulated by the Climate Change Commission (CCC) in accordance to Section 13 of the Philippine Climate Change Act of 2009 or RA 9729 which is to assess risks and impacts of climate change and identify the most vulnerable communities, areas and ecosystems. Moreover, Section 6(d) of the Philippine Disaster Risk Reduction and Management (PDRRM) Act of 2010 or RA ensures a multi-stakeholder participation in developing, updating and sharing DRRM information through GIS-based risk mapping policy, planning and decision-making tools for science-based analysis and information on geographically targeted interventions on climate change adaptation, mitigation and disaster preparedness. Agroforestry theoretically depicts a climate change-resilient farming system in terms of its ability to sustain productivity in the face of recurring climate variability and extremes. The ecosystem services of agroforestry being more diverse coupled with existence of water harvesting/impoundments offer opportunities to reduce the adverse effects of extreme climate events. Tropical fruits and bamboo/forest trees serve as windbreaks and soil erosion/runoff control during typhoons and monsoon rains. Backyard crops such as root crops provide alternative food and income during calamities to take the place of field crops (rice and corn) that have higher risks of damage. Water impoundments/groundwater provide available irrigation and potable water during periods of drought. Thus, vulnerability of farming systems to the impacts of climate change are reduced and become climate change resilient.

2 From overlaying various spatially-referenced biophysical and socioeconomic factors (e.g. topography, soil, climate, land use, demographic profile, farming practices, problems and constraints), GIS is capable of analyzing crop suitability for any agroforestry crop (tropical fruits and bamboo) in a given geographic region using sets of criteria based on ecological requirements. The study aimed to assess the climate change vulnerability of existing farming systems using geographic information system (GIS) and crop suitability of agroforestry crops (tropical fruits and bamboo) as intervention for enhancing the climate change resiliency of existing farming systems in the study sites. 2. METHODOLOGY 2.1 Selection of Study Sites Using the set criteria on high risk municipalities for floods, landslides and typhoons in Cagayan River basin identified by DENR-MGB and accessibility being near the national road, four LGUs were selected namely: Penablanca, Cagayan, Echague, Isabela, Maddela, Quirino and Bagabag, Nueva Vizcaya (Figure 1). 2.2 Climate Change Vulnerability Mapping Figure 1. Selected study sites. The climate change vulnerability mapping procedure of Yusuf and Francisco downscaled at Cagayan Valley was adopted following the IPCC framework that vulnerability is a function of exposure, sensitivity and adaptive capacity as follows: 1) Assessment of exposure using information from historical records of climate-related hazards as past exposure to climate risks are considered as the best available proxy for future climate risks. Climate hazard maps for the climate-related risks include tropical cyclones, floods, landslides, and droughts; 2) Use of population density as a proxy for human sensitivity to climate-hazard exposure. The assumption here is that regions that are relatively less inhabited will be less vulnerable compared to regions with high population densities, given the same degree of exposure to climate hazards; 3) In addition to the human aspect of vulnerability, ecological sensitivity of the region using biodiversity information is included as a proxy variable. A biodiversity-rich region, measured by the percentage of protected areas, is thus considered here as more vulnerable than other areas to climate hazards, other things being equal; and 4) Adaptive capacity is defined as the degree to which adjustments in practices, processes, or structures can moderate or offset potential damage or take advantage of opportunities (from climate change). It is a function of socio-economic factors, technology and infrastructure.

3 equal weights The cartographic models (Figures 2-5) indicate the map layer inputs, the geoprocessing used (reclassification, intersect) and the resulting output composite maps such as exposure, sensitivity, adaptive capacity and overall climate change vulnerability. Cartographic Model Exposure Map TYPHOON HITS TEMPERATURE INCREASE RAINFALL INCREASE CLIMATE RISKS RAINFALL DECREASE DUE TO EL NINO 0.1 EXPOSURE FLOOD-PRONE AREAS EROSION-PRONE AREAS 0.6 Merge MULTI-HAZARD Figure 2. Cartographic model for exposure map. Cartographic Model Sensitivity Map 0.6 POPULATION/ AREA (No. of indiv./ha) Calculate POPULATION DENSITY 0.6 PRIME AGRIC L LANDS SENSITIVITY FORESTS/ PROTECTED AREAS 0.3 Merge LAND USE SENSITIVITY BUILT-UP AREAS 0.2 OTHER LAND USES 0.1 Figure 3. Cartographic model for sensitivity map. Cartographic Model Adaptive Capacity Map HDI POVERTY INCIDENCE 1=H; 2=M; 3=L INCOME GAP 1=H; 2=M; 3=L TECHNO-GABAY (FITS+MS) CENTERS ROAD DENSITY HOUSE & LOT Merge SOCIO- ECONOMICS 1=H; 2=M; 3=L TECHNOLOGY 1=H; 2=M; 3=L 0.2 Merge ADAPTIVE CAPACITY 1/3=H; 1/2=M; 1/1=L STRONG HOUSES ELECTRICITY IRRIGATION SAFE WATER SOURCE Merge INFRA- STRUCTURE 1=H; 2=M; 3=L HEALTH CENTERS/ HOSPITALS TELECOMS (GSM & G3 COVERAGE) Figure 4. Cartographic model for adaptive capacity map.

4 Figure 5. Cartographic model for overall climate change vulnerability map. 3.3 Multi-criteria Crop Suitability Analysis Mapping of the biophysical conditions of selected farming systems using GPS and available geo-referenced digital maps and digital elevation model (DEM) and linking attributes on ecological requirements of tropical fruits such as climate (temp, rainfall), elevations and slope, and soil types (Table 1) as follows: Table 1. Basic ecological requirements of selected tropical fruits. Tropical Fruit/ Bamboo Mango Topography (Elevation & Slope) Requirements Flat to slightly rolling terrain Should not be higher than 600 meters above sea level as it delays fruit maturity at higher elevations. 400 meters ideal for growing mango Soil Requirements Sandy loam,relatively rich in organic matter Good drainage (very important) ph Climate Requirement Distinct wet and dry season (4 to 5 months dry priod) Temperature of 21 to 30 degree celsius No strong winds Sweet Tamarind Pummelo Lanzones Rambutan 400 meters ideal for growing pummelo. The best orchards are situated on the banks of current and former river courses. Should not be higher than meters above sea level. Plants can grow at m above mean sea level The tree tolerates a great diversity of soil types, from deep alluvial soil to rocky land and porous, oolitic limestone. It withstands salt spray and can be planted fairly close to the seashore. It can tolerate a wide range of soils from coarse sand to heavy clay. Optimum ph from 5.5 to 6.5 It prefers soil with good drainage and water retention; Rich in organic matter and slightly acidic. It cannot tolerate sandy coastal soils and alkaline soils. It prefers clay loam soil, but can be grown in a wide range of soil types. ph 5 to 6.5. Not water-logged. Distinct wet and dry season. Dry weather is important during the period of fruit development. Optimum temperature of 25-30o C Annual rainfall requirement mm It thrives best in humid condition, plenty of moisture. Some shade is beneficial especially during the early years. Best grown in the temperature range between 22C to 35C. Well distributed rainfall.

5 Figure 6 presents the cartographic model used in the crop suitability analysis using GIS. Meantime, the crop suitability was only limited to biophysical (topography, soil and climate) criteria to come up with a composite biophysical suitability map. Figure 8. Cartographic Model of Biophysical Suitability Analysis ELEVATION masl=h; 600-1,000 masl = M Above 1,000 =L SLOPE 0-18%=H; 18-50%=M; Above 50%=L SOIL TEXTURE Clay = H; Loam = M; Sand = L SOIL PH 6.5 = H; = M; Below 5 = L LAND USE/COVER Idle/Grasslands=H; Croplands/plantations=M; Forests/prime rice/ builtup areas=not suitable TOPO SOIL SOIL x LAND USE LAND BIOPHYSICAL TEMPERATURE = H; Above 28 = M; Below 22 = L; RAINFALL mm = H; mm = M; Below 100 mm = L; TYPHOON Freq > 10 = M; Freq 10 & below + typh tack = M; Freq above 10 = L TEMP x RAIN CLIMATE 3. RESULTS AND DISCUSSION 3.1 Geographic Locations and Areas of Existing Farming Systems in Cagayan Valley Figure 6. Cartorgraphic model of crop suitability analysis. The study sites were dominated with rice and corn farming systems (Figure 7). Figure 7. Dominant farming systems in Cagayan Valley and the Study Sites.

6 3.2 Climate Change Vulnerability of Rice and Corn Farming Systems Figures 8-10 are the layers used in generating exposure, sensitivity and adaptive capacity maps in Penablanca, Cagayan for example. Figure 8. Layers used in generating exposure map. Figure 9. Layers overlaid to generate the sensitivity map. Figure 10. Layers overlaid to generate the adaptive capacity map.

7 Overlaying the exposure, sensitivity and adaptive capacity maps, the overall climate change vulnerability map in Cagayan Valley with the rice and corn farming systems resulted to the following: Echague, Isabela had the highest land area with high vulnerability of 99, ha, followed by Penablanca with 22, ha, then by Maddela with 7, ha and Bagabag as the lowest with only ha (Figure 11). For the four study sites, most of the land area had low vulnerability with 298, ha, followed by moderately vulnerable with 176, ha while the lowest was highly vulnerable with 130, ha. Figure 11. Overall climate change vulnerability map Farming systems in the study sites. Based on the attributes of the layers, the exposure, sensitivity, adaptive capacity and overall climate change vulnerability indices (Tables 2-5) of the rice and corn farming systems in the study sites were tabulated and ranked as follows: Table 2. Exposure index of rice and corn farming systems in the study sites. Sensitivity Index of the Study Sites Table 3. Sensitivity index of rice and corn farming systems in the study sites. Study Sites Dominant Farming System Ave. Area Planted No. of Farmers Sensitivity Index Rank Penablanca Upland Corn Echague Upland Corn Maddela Upland Corn Bagabag Irrigated Rice

8 Table 4. Adaptive capacity index of rice and corn farming systems in the study sites. Table 5. Overall climate change vulnerability of rice and corn farming systems in the study sites. 3.3 GIS-based Crop Suitability of Climate Change-Resilient Tropical Fruits Topographic Suitability: For topographic suitability combining elevation and slope as overlay factors, all the tropical fruits (mango, pummelo, lanzones, rambutan and jackfruit) were within highly suitable topography (within 600 masl elevation and within 0-50% slope category). The eastern parts of Penablanca and Maddela which were the mountain ranges of Sierra Madre are moderately suitable. Also the mountain ranges of Caraballo made some parts of Bagabag and Maddela moderately suitable for the tropical fruits (Figure 12). Figure 12. Topographic suitability of the study sites.

9 3.3.2 Soil Suitability: Overlaying the soil texture, soil ph and Land Use maps produced the soil suitability map (Figure 13). Forests, built-up areas, aquatic areas and rivers were not suitable. Highly suitable areas were those that have loam to clay loam soil and croplands mixed with brushlands and grasslands. Figure 13. Soil and land use suitability of tropical fruits in the study sites Climate Suitability: Monthly temperature and rainfall were both suitable for tropical fruits considering temperature and rainfall ranges of oc and mm, respectively. However, frequent occurrence and tracks of typhoons in Cagayan Valley reduced suitability of tropical fruits (Figure 14). Figure 14. Climate suitability of tropical fruits Overall Biophysical Suitability: Overlaying topographic, soil and climate suitability produced the following overall biophysical suitability map (Figure 15). Figure 15. Overall biophysical suitability of tropical fruits in the study sites.

10 4. CONCLUSION AND RECOMMENDATIONS The monocrop corn farming systems in Penablanca, Cagayan and Echague, Isabela had the highest climate change vulnerability index considering that the crop had higher exposure to multi-hazards, more areas with more farmers affected, lower income, knowledge, perception and less access to land/water resources. All the tropical fruits (rambutan, Guimaras Mango, lanzones, pummelo) and bamboo were suitable to be planted in all the barangay study sites based on their basic ecological requirements: Elevation < 700 masl; Slope = 18-30%; Soil texture= sandy clay-loam; Soil ph > 5; Gen. climate = pronounced; Rainfall > 1,000 mm/yr; and Temperature < 30 o C. The climate change vulnerability of major farming systems should be disseminated to farmers, communities and LGUs and develop and formulate appropriate climate change adaptation plans for farming systems. Hands-on training on GIS for LGUs should be conducted in order to utilize the geodatabase on crop suitability and climate change vulnerability maps for climate change resilient-farming system planning and development. 5. REFERENCES DA-BAR, GIS Data (shapefiles, DEM) of Cagayan Valley. GODILANO, E.C. AND J.B. ABUNDA, Geographic Suitability and Investment Potential of Mango in the Philippines. DA-BAR. Pp. 53 GODILANO, E. C Geospatial Technology. New Tools, New Science, and New Opportunities in the Governance of Agriculture and Natural Resources. ICRAF Climate Change Adaptation and Mitigation through Agroforestrry. ICRAF Medium Term Plan, IFAD Climate Change: Building Smallholder Resilience. International Fund for Agricultural Development, Rome, Italy. MANILA OBSERVATORY AND DENR, Philippines. Mapping vulnerability to environmental disasters in the NSCB, Missing Targets: An alternative MDG midterm report. SOCIAL WATCH PHILIPPINES. National Statistical Coordination Board (NSCB). NSCB, City and Municipal Level Poverty Estimates. Published by the National Statistical Coordination Board Midland Buendia Building, 403 Sen. Gil Puyat Avenue, Makati City 1200, with funding assistance from the World Bank. PAGASA, Climate map of the Philippines. PAGASA, Climate Projections in Region 02. Climate Change in the Philippines. Adaptayo - MDG Achievement Fund - Pagasa. p.30 PEÑALBA, L.M., ELAZEGUI, D.D., PULHIN, J.M. AND R.V.O., CRUZ Enhancing the Climate Change Adaptation Capacity of Local Government Units and Scientists in the Philippines. Final Report. APN, Japan. July 31, VISAYAN SILENT-GARDENS WEBSITE Philippines GSM and G3 coverage. YUSUF AND FRANCISCO, Climate change vulnerability mapping for Southeast Asia. IDRC-CRDI, SIDA, CIDA, EEPSEA. YUSUF ET AL Climate change vulnerability mapping using GIS. Hands on Training Manual.