Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano

Msc-Thesis Soil sciences, specialisation Land sciences, WUR Author: Sylvan Nysten

Supervisors: dr. ir. Jetse Stoorvogel (WUR), dr. Peter Verburg (WUR), drs. Jan van der Ploeg (CML) and drs. Merlijn van Weerd (CML)

May 2009 - January 2010

In cooperation with the Cagayan Valley Program on Education and Development (CVPED), Cagayan, Isabela, the Philippines

Acknowledgements This research is a thesis for the master Soil science, specialization Land sciences of Wageningen University. The research was carried out in cooperation with the Cagayan Valley Program on Education and Development, which is a joint of Leiden University and Isabela State Univerisity, Cabagan, Philippines. Many people from these institutions have helped me during my thesis, for which I want to thank them all! First of all I want to thank Peter Verburg, initially my supervisor, for giving me the opportunity to do this thesis and helping me during the biggest part of my study. Merlijn van Weerd, one of my supervisors from Leiden Univerisity, I want to thank for all the support during my fieldwork in the Philippines. He has helped me a lot with doing my fieldwork, but also personally, thank you! My other supervisor from Leiden University, Jan van der Ploeg, I want to thank for being so enthusiastic and always willing to help me. Jetse Stoorvogel became my supervisor during the last part of my thesis. His advices have helped me a lot with making a good report, thank you! Furthermore I want to thank all the students who worked together with me in the Gaia building for the nice times. From Isabela State University, I want to thank late Sir Andy Masipiqueña, Wilda Calapoto, Arnold Macadangdang and Proceso Tarun for their help. Jessie Guerrero, Samuel Telan and Marites Balbas from the Mabuwaya foundation I want to thank for always helping me and making my (few) office hours fun. Willem van de Ven and Jeroen Admiraal, my house mates, thanks for all the fun at the international house! Last, but not least, I want to thank all the people who helped me with my field trips to San Mariano, especially my interpreters Maryjane R. Placido and Ryan Telan: without you this research was impossible. Staying with you in the jungle was just amazing! You both were a great support guiding me in the field. Because of all these people my stay in the Philippines was a good and valuable experience.

Sylvan Nysten, January 2010

Jane Ryan (right) with Raffy who assisted us in the field

I

II Summary This study focused on land use and land cover changes on the micro-level in relation to wetlands in the period 1950-2009. Freshwater wetlands are essential for the protection of the Philippine crocodile. The first step in this research is making wetland maps for 1950, 1970 and current wetlands. For the 1950 map, a topographic map was adapted to a wetland map. The 1970 map is based on satellite images and aerial photos. The current map for wetlands is derived from a digital elevation model. This map shows where wetlands potentially can be found. In combination with a land use description at the field level, the location of wetlands are known. With these maps, and the land use description, it becomes clear what has happened with the wetlands from 1950 onwards. These maps show that wetlands were initially increasing due to deforestation, but conversion to agriculture caused a decline in wetlands. Interviews with farmers are used to make the land use description, to get insights in conversion processes of wetlands and the driving forces for wetland conversion. It was assumed that wetlands are disappearing due to agriculture, especially wet rice cultivation. This is indeed the case, at some places wetlands are converted to rice fields. However, this is only on a very small scale. Corn has had a much bigger influence on the wetlands, although less direct because the stream or river remains intact. When the current situation is compared with 1950 or 1970, it can be argued whether there is a decrease in open wetlands at all. Because in 1950 almost the entire area was forest and only around the Pinacanauan and Disubungan river some open wetlands can be found. Immediate after deforestation, more open wetlands were “created” and although conversion to agriculture has taken place, it is difficult to estimate if there is a net decrease or increase in wetlands. Drivers for the conversion of wetlands are fertile soils with a texture that is not too coarse (fine sand or clay), low risk of flooding the surrounding fields, knowledge and self-sufficiency. Because wetlands are so fertile and fine textured in general, they are very suitable for use as agriculture. The fast growing population in the area created this demand for agriculture. Whether a wetland is converted to corn or rice is influenced by a risk of flooding at the specific location and the knowledge of the people. Rice fields are never at places with a high risk on flooding. The knowledge of a farmer determines to some extent which crops he cultivates. But when a new farmer start cultivating other crops, they are likely to copy this when the new method/crop is more productive. This is an important factor in the land use pattern, it explains why at two locations with similar spatial factors, different crops are grown. The need for self-sufficiency explains the conversion of small wetlands in remote areas to rice fields. Here the people need rice for their own food and that is why most of them have a small (less then 0.5 ha) rice field. The last research goal was to make a map that indicates potential habitats. It is possible to make a map that shows potential wetlands, but this is not yet a map of crocodile habitats. Many of the potential wetlands are already converted for agriculture. To map the wetlands that are not yet converted is not possible with just a DEM-analysis. But with help of a land use map, the areas that are most prone to conversion to corn and rice can be mapped. An accessibility map shows areas that are suitable because of lower population pressure. Places that connect the current habitats are also mapped. These maps together could be used to find the most suitable areas for wetlands. With the knowledge of the drivers for wetlands conversion, potential habitats can be distinguished from wetlands that are likely to be converted to agriculture.

III IV Table of contents ACKNOWLEDGEMENTS ...... I SUMMARY ...... III TABLE OF CONTENTS ...... V 1. INTRODUCTION ...... 1

1.1 CONTEXT ...... 1 1.1.1 Area description ...... 1 1.1.2 Crocodylus mindorensis...... 1 1.1.3 CVPED/CROC...... 2 1.2 AIM OF STUDY ...... 3 1.3 RESEARCH QUESTIONS ...... 3 2 BACKGROUND...... 5

2.1 CROCODILE AND ITS HABITAT ...... 5 2.2 CURRENT LAND USE ...... 5 2.3 CHANGES IN LAST 40 YEARS AND DRIVING FORCES ...... 5 2.3.1 Proximate Causes ...... 6 2.3.2 Underlying Causes ...... 6 2.3.3 Other Factors...... 7 3 MATERIALS + METHODS ...... 9

3.1 WETLAND MAPS ...... 10 3.1.1 Wetlands in 1950...... 10 3.1.2 Wetlands in 1970...... 10 3.1.3 Potential wetland map ...... 11 3.2 INTERVIEWS ...... 13 3.2.1 Land use...... 14 3.2.2 Drivers ...... 15 3.3 POTENTIAL HABITATS ...... 17 3.3.1 Validation of potential wetland map...... 17 3.3.2 Land use threats ...... 17 3.3.3 Population density/Accessibility...... 17 3.3.4 Awareness ...... 17 3.3.5 Connectivity...... 17 4 RESULTS ...... 19

4.1 LUCC IN RELATION TO WETLANDS ...... 19 4.1.1 Wetlands in 1950...... 19 4.1.2 Wetlands in 1970...... 19 4.1.3 Potential wetlands...... 19 4.1.4 Land use...... 21 4.2 DRIVERS ...... 27 4.2.1 Spatial characteristics...... 27 4.2.2 Temporal characteristics ...... 30 4.3 POTENTIAL HABITATS ...... 32 4.3.1 Validation of potential wetland map...... 32

V 4.3.2 Land use threats ...... 33 4.3.3 Population density/Accessibility...... 35 4.3.4 Awareness ...... 35 4.3.5 Connectivity...... 36 5 DISCUSSION...... 37

5.1 INTERPRETATION AND COMMENTS ON THE RESULTS ...... 37 5.1.1 LUCC in relation to wetlands ...... 37 5.1.2 Drivers ...... 38 5.1.3 Potential habitats...... 39 5.2 SWOT ...... 40 5.2.1 Data of the maps...... 40 5.2.2 Interviews ...... 40 5.2.3 Applicability...... 40 6 CONCLUSION...... 41 APENDIX A: INTERVIEW...... 43 APPENDIX B: LAND USE PER BARANGAYS ...... 45 APPENDIX C: CROP CHANGES PER BARANGAY: ...... 47 REFERENCES ...... 49

VI 1. Introduction

1.1 Context In the last 50 years there has been a lot of land use and land cover change (LUCC) in the Philippines. This is due to an interaction between fast population growth, the associated migration of people that seek for land, and commercial logging. A major impact of population growth on land use is deforestation for agricultural purposes and subsequently the conversion of wetlands to rice fields (Kummer 1992), (ESSC 1999). This started already around 1900, when Christian immigrants claimed land on a small scale for rice cultivation. The effects of deforestation on biodiversity depends on scale and deforestation pattern as mentioned by Nagtegaal (2007). In the Philippines the unique conditions in combination with small scale deforestation of the past made the area one of the most important hotspots for biodiversity. In the period between 1970-1990 45% of the forest was cleared due to commercial logging (Van den Top, 1998). The impact on the environment of clearing on this scale is severe due to habitat and biodiversity loss (Tilman, May et al. 1994), (Turner 1996), (Myers, Mittermeier et al. 2000) in an area so rich in (rare) species. This is illustrated by the habitat loss of the Philippine crocodile (Crocodylus mindorensis), which needs wetlands for reproduction (Weerd and Ploeg 2008). Assumed is that most of these wetlands are converted to agricultural land, because these areas are very suitable for rice cultivation and, more recently, fishery. Another threat to the habitat of the crocodiles and its preys is dynamite and electricity fishing which caused biodiversity loss and is a direct threat for the Philippine crocodile itself. Additionally, although the crocodiles are protected by law, not so many people respects this law, so these fishing methods can’t be stopped (Ploeg and Weerd 2008).

1.1.1 Area description The study area is the municipality of San Mariano, see fig 1.1, is situated in the northeast of Luzon, Philippines and has a size of 48,000 ha. The area was subject to deforestation in the previous century and today less than one third of the forest remains. The cleared parts are now mainly agriculture. Four rivers, of which the Pinacanauan river is the west boundary of the study area, are coming together in the area and influence it because these rivers are important for the drainage/irrigation system. This influence can be observed in the land use pattern; rice and corn is cultivated near the rivers, while banana’s are grown on higher altitudes. Also most villages are located in the neighborhood of a river. The other rivers are Disubungan, Disulap river and the Catalangan river. The area includes 23 barangays (small settlements) and a total population of approximately 20,000 people. The population consists of different ethnic groups: Ilocano, Ibanag and Ifugao (Overmars 2006). The area is limited in the east by the Sierra Madre mountain range, which is a protected area. This area is still covered with tropical forest and is the largest piece of tropical forest in the Philippines. The reason for this is its inaccessibility (Nagtegaal 2007) that makes (illegal) logging difficult.

1.1.2 Crocodylus mindorensis Crocodylus mindorensis, or Philippine crocodile, is a small endemic freshwater crocodile. It is one of the most endangered reptile species in the world (Weerd and Ploeg 2008). The crocodile was almost extinct when a nest of crocodiles was discovered in 1999 in the municipality of San Mariano, Isabela Province. From then on a project was started to protect the species by making the people aware of its value and learn them that the animals are not dangerous. Hunting was, and still is, a problem, but as soon as people knew the crocodile is not dangerous, the problem diminished a bit. Now, after many promotion campaigns, most people are proud that the crocodile lives in their surroundings and cooperation with locals helps protecting it. In spite of this, still a lot of work has to be done before Crocodylus mindorensis isn’t an endangered species anymore. Creating more space for the crocodile is one of these things.

Chapter 1 – Introduction 1

Figure 1.1: Location of San Mariano, Isabela (left) and the study area (right)

1.1.3 CVPED/CROC CVPED is a partnership of Leiden University and Isabela State University which plays a key role in the protection of the Philippine crocodile in northeast Luzon. They started the CROC, crocodile rehabilitation observance and conservation, project in combination with Isabela State University and Leiden University, but is now independent. In 2003 a foundation was started with the name Mabuwaya (long live the crocodile) Foundation to assure the continuity of the crocodile conservation activities. A lot of research is done by the Mabuwaya Foundation to know how the Philippine crocodile lives in order to be able to conserve it. Currently, the project tries to implement a comprehensive ecosystem approach where local officials are trained to protect wetlands that are important for the conservation of the crocodile (cvped.org, March 2009). In the past, much work has been done on communication and public awareness, because this is important to prevent hunting and other unnecessary threats. But also a telemetry study has been carried out in 2005. CVPED works together with the protected area wildlife service (PAWS) and the local people and governments to work as effectively as possible.

2 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 1.2 Aim of study To implement a comprehensive ecosystem approach that protects the wetlands for crocodiles, good information about what has happened with the wetlands in the last decennia and why this has happened is needed. The LUCC focusing on wetlands has to be described. For this research wetlands include rivers, creeks, streams, marshes, swamps, lakes and ponds. Although wet rice fields are in fact wetlands, they are considered as agriculture and not as wetlands, because the crocodile is not desired in a rice field. Creeks and rivers are included in the wetlands, because the crocodile does not only live in wetlands but also in these creeks and rivers. When more is known about the land use changes in relation to wetlands (the micro level), measures can be taken to protect the crocodile habitat and maybe even new habitat can be “created”. LUCC has been studied in the area by Overmars (2006), but this study did not focus on the micro level. For that reason an additional study is needed for LUCC on the micro level. The purpose of this research is to give information about LUCC in relation to wetlands at this micro-level scale. This includes information about the changes in open wetlands in San Mariano and the conversion processes related to this. Information about the changes in wetlands can be given by making maps of the wetlands for different time periods, starting from 1950 onwards. An analysis of driving forces for LUCC is essential to fully understand the effects of wetland change. Another aim of the study is to find potential habitats for the Philippine crocodile and make a map of these locations. A map of the current wetlands (biophysical suitability) and a map that indicates the risk of threats for the crocodile (threat map) are needed for this. A combination of these two maps shows where potential habitats can be found.

1.3 Research questions The aims of the study can be reformulated in 3 research questions:

1. What are the LUCC in the period 1950-2009 at the micro level in San Mariano, focusing on wetlands? Hypothesis: Wetlands are converted into agriculture, particularly rice. Damming for fish ponds can have a positive effect on the numbers of wetland, although the negative effect of agriculture has a much bigger influence. The amount of wetlands has decreased dramatically since 1970, because these wetlands are the most suitable areas for rice cultivation, because of their high fertility. The construction of dams result in good fish ponds with highly fertile soils.

2. What are the driving forces for wetland conversion? Hypothesis: The most important drivers for wetland conversion are agriculture expansion, logging and infrastructural extension. Underlying threats are population growth and weak governance mechanisms, but also factors such as soil and slope can be important drivers.

3. Is it possible to create a map that shows wetlands that are suitable for use as juvenile crocodile habitat? Hypothesis: Wetlands can be mapped using digital elevation models (DEM). In combination with knowledge of the driving forces for wetland conversion and direct threats for the crocodile it is possible to make a suitability map for habitats.

Chapter 1 – Introduction 3

4 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 2 Background

2.1 Crocodile and its habitat Crocodylus mindorensis could probably be found in big numbers in the Philippines a hundred years ago (Ploeg and Weerd 2008). This crocodile lives in big rivers, but needs small wetlands for reproduction. These small wetlands are important in times of flooding. The crocodile, especially the young ones, seek protection in these wetlands when the river floods and for that, these wetlands are essential for this species. However, the area of wetlands is considered to be in decline since 1970 and with that the habitat for the young crocodiles. For the survival of the species it is therefore important to reestablish suitable wetlands that can function as refuge place during the rainy season and as nursery pools for hatchlings and juveniles.

2.2 Current land use A land use map for 2001 was made by Verburg et al (2004). This map was derived from satellite images of ASTER and Landsat with a resolution of 50x50 m. Different classification methods were combined to make a good distinction between different land uses. This map shows clearly the overall land use pattern in the study area. The most eastern part is still primary forest with a gradually transition to secondary forest in the west. In the western part, deforestation has occurred and agriculture is now the main land use. Bananas are the main crop on the higher altitudes and corn near the rivers. Wetland rice can be found on small spots where irrigation is possible. Grassland is situated on places that are not suitable for cash crops.

2.3 Changes in last 40 years and driving forces In the last 40 years, the land use has changed a lot due to different driving forces. Most important change is the deforestation of a big part of the area in favor of agriculture. This was the result of high population growth and migration rates and the accompanying demand for land. So the area changed

Chapter 2 – Background 5 from a tropical rainforest to agricultural land with some forest patches remaining in the eastern part. The deforestation came to an end in 1992 by a logging moratorium. In 1989 there was already a moratorium but that one was lifted in 1990 (Overmars and Verburg 2005). Another LUCC is the (assumed) decline in wetlands. Assumed is that the intense water control for agriculture (rice cultivation) is the main cause. Examples are draining of swamps, damming of (small) streams and the origination of fishing pools. These forms of water control change the natural hydrological cycle and affect in that way the natural wetlands, which are so important for the Philippine crocodile. The driving forces that result in deforestation, and wetland decline, can be divided into proximate causes and underlying causes (Geist and Lambin 2001). Where the proximate causes are human activities that directly influence the environment. These causes are factors resulting directly from specific land uses. These proximate causes can be subdivided into 3 groups: • crop land expansion • harvesting or extraction of wood • infrastructure expansion

Underlying causes are fundamental driving forces that underpin the more obvious proximate causes. Subdivided into: • social • economic • political • technological • cultural Furthermore Geist and Lambin distinguish “other” factors. These can be land characteristics such as soil and slope, but also social trigger events.

2.3.1 Proximate Causes In our study area, the crop land expansion and wood extraction are the most important drivers of wetland decline and deforestation. Crop land expansion can be seen directly in the field by the draining and damming for respectively agriculture and fishery, as mentioned above. The origination of rice fields, needs a good drainage system and fishery needs dams. Both are destroying the crocodiles habitat. Cultivation of rice is threatening the habitats also by disturbance caused by agricultural activities. Fishery “pools” on the other hand, can have a positive effect for crocodiles; These pools can serve as a habitat for the crocodile. Wood extraction was important until 1992. After 1992, there was still some illegal logging, but on a much smaller scale. Infrastructural extension has never been a very important factor, although the big commercial logging companies have made some roads for their logging activities. After the logging moratorium, these roads were not maintained anymore.

2.3.2 Underlying Causes Migration and population growth is probably the most important underlying cause for deforestation and wetland decline. Because all the migrants were seeking for land to cultivate. But migration itself is not a driving force, it is the demand for land that drives deforestation and wetland conversion to rice fields. Due to the population growth, the area became deforested from west to east. People living along the big river in the west, started to clear the areas. When the area was cleared, the wetlands were converted to rice fields, while other areas were used for other crops like corn. Another indirect threat are the governance mechanisms that are not functioning very well in the Philippines (cepf 2001). This makes protection and law enforcement not very effective. This makes it also more difficult to make the people aware of the value of the Philippine crocodile. However, the public awareness is of great importance for the protection of the crocodile. If public awareness is low, (illegal) hunting increases and people are not prepared to protect the animal. Ethnicity is an

6 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano important factor too, because different ethnic groups have a tradition in growing specific crops: Ibanag cultivate mainly corn, Ifugaos and Ilocano (Tagalog speaking) cultivate rice (Overmars and Verburg 2005). Due to the spatial distribution of these ethnicities, some areas are more sensitive to conversion than other areas. So areas with Tagalog speaking people are more sensitive to wetland conversion than those where Ibanag people live. World food prices for specific crops have a big influence on the crop choice of a farmer (Overmars 2006). These food prices however, depend highly on plant diseases in the world. When shortages of a specific crop originate, the price will increase. That means that a crop is more profitable for a farmer and of course that influences the land use pattern. Bananas are a perfect example of this, a fungus destroyed many banana plantations, which increased the price of bananas. The result is that banana plantations are much more profitable than before. This resulted in an increased amount of banana plantations in the Philippines.

2.3.3 Other Factors Accessibility is an important factor in land use changes. According to (Overmars and Verburg 2005), distance measures are explanatory factors in all of their 3 models. These distance measures are distance to village , distance to road and distance to market . So these distances are explaining land use changes very well. The further away from villages, roads and a market, the less land conversions are likely to occur. Slope turns out to be an important factor as well in the models of (Overmars and Verburg 2005). The reason for this is that some crops are better suitable to grow on slopes than others. Rice for example cannot be grown on steep slopes, while bananas are well adapted to steep slopes. It depends partly on the soil type whether an area is suitable or not for conversion to agriculture or fishery. In that way the soil is a spatial driver for deforestation, but it does not drive deforestation itself. River or streams are an important driver for conversion to rice cultivation, because it is easier to build a drainage system when there is already a stream or river. Landownership is a driver for land use, because a farmer is not willing to pay for adapting a piece of land when he is not sure he can use that land for a long period. Only if he is the owner of the land he is sure that he can use the land for a long period and can make profit of it.

The driving forces are summarized in table 2.1 and further divided in temporal and spatial factors. This subdivision can be useful, because the spatial factors can be seen in the field while temporal factors have to be investigated by questionnaires. This is of concern for the fieldwork, which will be explained later in the chapter of the methods. Some factors can be classified as temporal and spatial such as ethnicity. On the one hand it is a temporal factor because different ethnic groups immigrated at different times, but on the other hand it is spatial, because they are settled in different areas of the study area. Accessibility is a spatial factor in the table, but it can also been seen as temporal; the change of accessibility in time. The same is true for (increasing) agriculture, if it changes it is temporal but it can also be a spatial factor. Table x: Driving forces

Table 2.1: Driving forces subdivided in temporal and spatial factors

Temporal factors Spatial factors Immigration and population growth Land use surrounding wetlands Food prices/plant diseases (correlated) Mining and logging Increasing agriculture Fishery pools Governance mechanisms Accessibility Public awareness Slope Ethnicity Soil Landownership River or stream

Chapter 2 – Background 7

8 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 3 Materials + methods To answer the research questions properly, the research is divided in 3 sections: 1. LUCC in relation to wetlands 2. Interviewing 3. Potential habitats To know the land use and -cover changes in relation to wetlands in northeast Luzon, first the wetlands have to be located for different times. This is done in the first phase, in that way the changes in wetlands are visualized and can be interpreted. Comparing wetland maps of different times shows whether wetland decline has occurred and also which areas are influenced most. A topographic map (U.S._Army_Map_Service, 2009) made in 1954 gives the earliest indication of the open wetlands in San Mariano. The map shows the forest borders, wetlands and agriculture. This can be adjusted to a map that shows open wetlands in the 50’s. On basis of aerial photo interpretations and a satellite classification a map for the 70’s is made. To create a current wetland map, a DEM analysis is combined with a deforestation map. This map, based on a DEM, shows the probability that there is a wetland. This is not a map of the actual wetlands, but it shows the pattern where wetlands can be found with high detail (15 m resolution). In combination with a description of the land use at the micro-level, this gives good information where wetlands can be found. The differences in methods for the 3 maps can be explained with the available data. For 1950 there is simply no other data available except a topographic map. For 1970 there are satellite images (Landsat MS) available and aerial photos. Since the research focuses on the micro-level, it is necessary to get as much detail as possible in the maps. Aerial photo interpretation is for that reason the best option. To make the interpretation more efficient, first the satellite images are used to get a first impression where to look for wetlands. For the current wetlands a DEM, satellite images and a land use map are available. The DEM contains the most detailed information. But a DEM analysis itself can only provide us with a probability map for wetlands, so more information about land use is needed to know where wetlands are located. This information is obtained by interviewing farmers in the study area. For the 50’s or the 70’s we cannot get this information. That is why this method can only be applied for current wetlands and not for the 50’s and 70’s. Farmers are interviewed to obtain the information about LUCC, its drivers and the conversion processes. The type of land use close to wetlands is described to get a better understanding of the LUCC concerning wetlands. Although the land use has been studied at a coarser scale, it can be helpful to study the land use at the micro level. A land use study at a coarser scale does not link the land use pattern in relation to wetlands, because these wetlands are in general too small to be taken into account in models at the regional level. In addition also the land use changes of the past are examined. Wetlands can be quite heterogeneous, which will lead to different conversion processes. For example a big river is less likely to be converted to a rice field then a small stream in a remote area. When the location of the wetlands and the driving forces for LUCC are known, potential habitats can be located.

Chapter 3 – Materials and methods 9

3.1 Wetland maps

3.1.1 Wetlands in 1950 A topographic map of 1954 shows already the wetlands, rice paddies and forest borders at this time. So this map can directly be used to locate the wetlands. It should only be geo-referenced and the legend has to be adapted.

3.1.2 Wetlands in 1970 Data To make a reconstruction of wetlands in 1970, aerial photos are used. The quality of the photos varies, what makes them sometimes difficult to interpret. Therefore the aerial photos were combined with a classification of a satellite image of 1979. Although the land cover has probably changed a bit in the period between 1970-1979 and the resolution of the image is too broad, they can help to find the main locations of the wetlands. When the classification is overlayed over the photos in ArcGIS, the wetlands can be drawn in with good detail.

Criteria The classification of wetlands is based on the classification of a satellite image and aerial photo interpretation. First the main areas where wetlands are located were selected on basis of the satellite image. The next step is to check these areas with the aerial photos. Some areas are removed, others are added until all the wetlands are delineated. Two classes of “wetland” are distinguished; “wetlands” and wetlands converted to agriculture. These classes could be distinguished because agricultural fields can be seen on aerial photos as rectangles with some grey scale contrast between the fields. With the satellite image it was not possible to distinguish between both due to the resolution. Areas that are covered with forest are not suitable as crocodile habitat and for that reason excluded as wetland.

Flowchart See figure 3.1 for the flowchart of the wetland map in 1970. This classification has served as basis to delineate al wetlands. In addition wetlands that are already converted to agriculture are also delineated. A land use map of 1970 was used to check whether the land was covered with forest or not.

Figure 3.1: flowchart wetland map 1970

10 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 3.1.3 Potential wetland map Data To make a map for current and potential wetlands a DEM is used which was derived of contour lines. There were also 2 other DEM’s available that were based on remote sensing. The cell size for the contour DEM is 15 m, while the remote sensing DEM’s have cell size of 50 and 90 m. A remote sensing DEM should also be corrected for vegetation (especially trees) and other high objects. However, the remote sensing DEM’s contain more information at the higher altitudes in the area. The choice for the contour DEM has been made because of a smaller cell size and it needs no correction for vegetation. The somewhat more detailed information on higher altitudes is not necessary, because these areas are of no interest for crocodile habitats (see also below). For current and potential wetlands another approach is used as for the wetlands in 1970.The DEM- analysis is the most accurate method. However, a description of the land use and cover is necessary to know where actual wetlands can be found. Beside the accuracy, another advantage of this method is that locations can be found that can be converted (back) to wetlands.

Criteria Before using the DEM to select locations that can be a potential wetland, some criteria should be defined. A wetland should, as the name implies, be wet for at least a part of the year or being a stream, creek or a river. This means that a wetland needs to be an area where water can accumulate, either by being a relative low point in an area where water flows to, or because of impenetrable layers caused by a specific geology. In this study we will mainly focus on the first category. An important criterion is that an area is flat. Hilly or mountainous areas have too much surface run- off or water infiltration. The area will be divided in different slope classes. The classes with she smallest slope have the highest chance to be a wetland. We have to take into account that the slope in a DEM is an average value and that even areas with big slopes can consist flat areas. The altitude is also an important criterion, because wetlands are usually found in the lowest areas. For height we can do the same as for the slope by dividing the area in different altitude classes. To get good water accumulation, the area should also be lower than its surroundings. Another criterion is that wetlands should be in a specific range of one of the 4 main rivers. One reason for this is that wetlands are mostly found along rivers, but it is also essential because the adult crocodiles are mainly found in the big rivers. Based on the maximum distance that the Philippine crocodile can travel (as far as known) over land, wetlands should be in a range of 3000 m of a big river.

Flowchart See figure 3.2 for the flowchart of the potential wetland map. The first thing to do is reclassifying the DEM into 10 relative chance classes with an equal interval between the minimum and maximum. The same is done for the slope map, but this time with a geometric interval. For the distance to the river a Euclidean distance was carried out and this was divided into 10 classes of 300 m. The DEM was also used to select areas that are situated relative low compared to the surroundings. Focal statistics were used to find the minimum value in an area of 10 cells (150 m). This minimum of an area was compared with its real value, again with “single output map algebra”. If a pixel has a value that is more than 1 m higher than its surrounding minimum, it was not selected. If a pixel is the minimum, or less than 1 m higher than its surrounding minimum, it was selected. The procedure was repeated 6 times with different values compared to its minimum. The first class contains areas that are maximum 1 m higher than the lowest point in the surroundings, the second class is maximum 2 m higher than its surroundings etc. till the last class that is 6 m higher than its surrounding. The areas that are 1 m higher or less get the highest chance while the parts that are 6 m higher or more get the lowest relative chance. These 4 maps, each with values ranging from “1” to “10”, are multiplied. The resulting map contains values ranging from “1” to “10.000”, where the higher values indicate a higher relative probability to find a wetland.

Chapter 3 – Materials and methods 11

When the map with relative probabilities is combined with a deforestation map of 2001, we get a map that shows where potentially open wetlands can be found. For this the land use map of 2001 has to be adapted so that it only shows forest as land use. This “new” map is used to select only the cells in the potential wetland map that are not covered with forest. However, many wetlands have already disappeared because of the land use changes. Most of the land in San Mariano is used for agriculture and depending on the specific land use, the wetlands have disappeared or are affected. This will be discussed in the next section.

Figure 3.2: Flowchart of the potential wetland map

12 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 3.2 Interviews After the freshwater wetlands are located it is necessary to know the land use in the study area at the field level. An existing land use map for 2001 (Overmars) gave a first interpretation of the land use pattern. In addition, interviews are used to get more insight in the land use and cover at the field level. In these interviews farmers are asked which crops they cultivate. This is done for several barangays in the study area and gives some information about the spatial distribution of the crops and its effects on the wetlands. The interview also includes questions about drivers for LUCC and conversion processes of wetlands. During a first field trip, crocodile habitats in San Mariano were visited to get a first impression of the study area. During this trip a questionnaire for the interviews was tested. This was necessary to adapt the questionnaire and the interviewing technique. This resulted in a final questionnaire (see Appendix A). To get useful data, the study sites are chosen in such a way that they have a good spatial distribution so that information will be obtained that is representative for the whole area. Figure 3.3 shows the locations of the selected barangays. The respondents in these barangays need to be selected randomly. For this research the selection is done stratified randomly for each selected barangay. From each barangay, approximately twelve respondents are selected using random numbers. A barangay normally consists of different puroks (districts) and depending on the number of puroks, between 2 and 4 respondents per purok are selected. From the 23 barangays in the study area, 7 are visited for interviewing plus some interviews in remote sitio’s: • Sitio’s (Diwagden, Dunoy, San Isidro) • Minanga • Del Pilar • Alibadabad • San Jose • Panninan • Disulap • Daragutan-East During the validation of the current wetland map (as discussed in section 3.3.1), also some field observations of the land use are made. This data is added to the information of the interviews.

Figure 3.3: Selected barangays for interviews

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3.2.1 Land use Current land use During the interviews, the farmers is asked how much land they have and what the land use is. To get a good idea of the land use pattern, they are also asked to describe how the land looks like. Some farmers were asked to make a sketch of their fields and the land use pattern. Making a sketch of their fields turned out to be a good communication method. In this way the land use pattern at the field level becomes clear. Important about these descriptions is the way the wetlands are located in relative to the different crops, which crops are close to ponds, streams or marshes? In combination with the other observations during the hiking, a good description of the land use is given.

Land use (crop) changes in the last 50 years The farmers are also asked which crops they have cultivated in the past. This is done to see whether the land use has changed in the last 50 years and also what the reasons are for these changes. The crop changes in the past can indicate if, for example, wet rice cultivation is indeed increasing as is assumed.

Conversion processes When we look to the different land uses and the locations of the wetlands, we can define different conversion processes for the wetlands. There are many different types of wetlands which are all differently affected by the land use. The following types of wetlands are distinguished: • Big rivers • Valley streams (with SWIP’s) • Hilly areas around wetlands: Rice terraces • Bigger streams and creeks • Small streams • Marshes • Swamps The conversion processes of each of these type of wetlands is described on basis of field observations and dialogues with farmers. Some farmers made a sketch of their land and how they influence the streams or wetlands in the area. In this way good qualitative descriptions of the conversion processes are given.

14 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 3.2.2 Drivers To get better insights in LUCC in relation to wetlands, we need to know the driving forces of the land use change. To obtain this, the interviews as discussed earlier, are used again to know which factors are important. The questionnaire contains questions about ethnicity, land ownership, crop choice (current and past), spatial factors, knowledge and awareness of crocodile protection. With the data of the interviews, relations between land use and its drivers can be found. In order to make a good analysis of the data, SPSS is used.

Spatial factors Opinion of farmers (importance) on spatial factors The spatial factors soil, slope, stream presence and accessibility play probably an important role on the crop choice by a farmer. To know to what extent each factor is important, the farmers are asked to rank these factors for each crop that they cultivate. For example, what is most important to cultivate the crop corn, a suitable soil or slope or the presence of a stream or the accessibility of the field? No more specific information was given to the farmer about what is suitable. They could decide themselves whether a suitable soil is related to texture or fertility or a combination of these. A suitable slope can also be either flat, rolling or steep. Accessibility can relate to (in)accessibility of the field to the farm or farm to the market. The reason for this is communication difficulties. It turned out quite hard to explain the farmers what was meant with this question. The farmers are not used to these kind of questions and the language barrier did not help either. That is why this question remained very open, but to get a good interpretation of the results, some further questions were asked when the answers were not clear. In this way the desired information was still obtained, although more indirect. To analyze the importance of these 4 spatial factors, the ranking is translated to a score (1-4). The most important factor gets the highest score of 4, the next factor 3, decreasing to 1. In this way for all crops, all 4 factors get an average score with a standard deviation which can be compared to each other. This average is a weighted average to area, so that bigger fields get a higher weight. Together with the additional information that farmers gave, the spatial factors can be related to the crops.

Soil(fertility/texture) The texture can be important for the choice of a crop. To know which crops can be found on which textures, the farmer is asked to describe this texture for his fields per crop. Later these descriptions can be translated to a texture class: • Clay • Fine • Sand • Coarse In this way, frequency tables can be made per crop. In other words, how much area of a crop is located on clayey soils, how much on sand etc. The frequencies could be measured in two ways; per crop or per texture class. In this case the frequencies of the crop are used. When we would take the frequencies per class, corn would be the most abundant crop on all texture classes, simply because it is by far the most abundant crop in the area and this will not give interesting data about texture as a driver.

Fertility of the soil is of course important for a crop in order to get a high productivity. To find a relation between crop and fertility, the farmers are asked to describe the soil color. The color of a soil is usually a good indicator of soil fertility. In San Mariano there is a broad range of colors in soils. Red soils are said to be the least fertile, next are the yellow soils, followed by a “in between” class (red with brown on top, yellowish brown etc.), brown indicates fertile soils and black are the most fertile. So there are 5 classes of “fertility”. Also for fertility a frequency table per crop is made.

Chapter 3 – Materials and methods 15

Slope Slope can be an important spatial factor for the crop choice. Especially in the context of LUCC in relation to wetlands. For each crop a description is given of the slope of the fields by the farmer. These descriptions of slopes can be categorized: • Flat • Terraces/slightly steep/plains • Moderate • Rolling • Steep Also for the slope a frequency table is made per crop. It can be interesting to see whether there are more crops, beside wet rice, that are more prominent on flatter areas then at steep locations.

Temporal factors Accessibility (farm-field) The accessibility of the fields (relative to the farm) can be a driver for land use. Some crops need more management than others. This makes it important for these crops to be located close to the farm, while other crops can be further away. For each field the farmer is asked to make an estimation of the travel time for walking to his fields. These travel times are averaged, weighted to area, per crop and this average travel time is a good estimation of the accessibility of the fields.

Ethnicity In San Mariano there are many ethnic groups. The biggest group are the Ilocano’s. The other two main ethnic groups are Ibanag and Ifugao and furthermore there are some minorities. Each ethnic group has a different background and culture. This difference in culture also has an influence on the cultivation of the land. To find out the differences in crop choice between the ethnic groups, frequency tables are made per ethnic group. For this factor, frequency tables per group are taken instead of per crop, because the Ilocano’s are by far the biggest group.

Landownership The official status of a field can influence the land use. When a field is owned with a land title, a farmer might invest more in his land compared to a farmer who only owns the land informally. The following landownership’s can be distinguished in San Mariano: • Land title • Stewardship • Declaration • Informal • Tenant • Process to land title With a frequency table per crop, it can be seen whether there is a relation between landownership and crop choice.

Knowledge and other drivers for land use To get better insights in the drivers it is necessary to ask further on some questions during the interviews. In that way some extra information is obtained that would otherwise be lost. This information is given in a descriptive way.

16 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 3.3 Potential habitats

3.3.1 Validation of potential wetland map To create an appropriate and useful map for current wetlands, the map needs to be validated. This is done by hiking through the study area along the 4 main rivers in the study area to find wetlands or converted wetlands. These rivers are: Pinacanauan, Disubungan, Disulap and Catalangan. Furthermore, there is one interesting area which needs to be checked too. This area was probably a marsh previously, an old river meander (Lamag). During this validation, GPS data of different wetlands are acquired. For each GPS point a data form and a photo is made. This dataset will be used to validate the potential wetland map. The data of the validation points is available in an ArcGIS project. Because the map with current and potential wetlands is in fact a probability map, the data points can be plotted in the map and a histogram can be made of the probabilities. This gives an indication of the quality of the map. Also an visual interpretation is made on basis of the location of rivers, wet rice fields and the location of the data points.

3.3.2 Land use threats The land use map of 2001 is used to indicate which crop threatens the wetlands the most. In this land use map the different crops can be selected, so that 3 maps are made that show only the selected crops (either corn, rice or banana). The new maps are combined with the current wetland map, which makes it possible to see whether the crop is threatening (part of) the wetlands. Although this land use map does not represent the field level perfectly, it does show the general patterns.

3.3.3 Population density/Accessibility A high population density is one of the main threats for the crocodile. This is because of the more intensive agriculture and partly because of hunting. Close to San Mariano Centro no crocodiles will be found because of this. So wetlands that are suitable for juvenile crocodiles have to be in the more inaccessible areas, to the south and east. An accessibility (distance to market) map is made as an indicator for the suitability related to population density.

3.3.4 Awareness To allocate potential wetlands for the crocodile, it is important to know something about the awareness of people concerning crocodile conservation. Hunting is an important threat for the Philippine crocodile. To take away this threat, much efforts are made to make the local people aware of crocodile conservation and its benefits. So it is assumed that the surroundings of barangays with people that are aware of the conservation, are more suitable than locations where people are not aware. By asking people the question: “Is crocodile hunting prohibited by law?”, an estimation is made of the awareness of people in different barangays.

3.3.5 Connectivity It is important that crocodiles in different rivers can reach each other. The different rivers are only connected to each other near the town centre of San Mariano, but due to the human threat the crocodiles are isolated from each other. When the wetlands are situated in a way that they can “connect” the rivers, then the crocodiles are less isolated. The wetlands should serve as stepping stones for the dispersal of the crocodiles. This should enhance the exchanges of genes between the populations. (Baum, Haynes et al. 2004) So before deciding which locations are best to use as new crocodile habitat, it should be checked which locations connects the “old” habitats most. For that a map is created that shows the distance to current habitats. The most suitable areas are those that are not too close to the old ones, because in that case the habitats are still not connected. Preferred are the areas that are in the middle of the current habitats, because that would halve the distance that a crocodile has to travel to another habitat.

Chapter 3 – Materials and methods 17

18 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 4 Results

4.1 LUCC in relation to wetlands

4.1.1 Wetlands in 1950 The wetland map for 1950, see figure 4.1, shows that the wetlands (blue parts) in San Mariano were found around the rivers Disubungan and Pinacanauan in combination with their swamps and some other smaller rivers/creeks. The population was restricted to the areas close to the town centre in the northwest and along the Pinacanauan river. The rest of the area remained forest. Some parts of the wetlands are already converted to wet rice fields (the northern part of Pinacanauan), while other parts are still swamps.

4.1.2 Wetlands in 1970 A satellite image interpretation in combination with aerial photos shows the location of wetlands in 1970, see figure 4.1. Obviously there is an increase in wetland area compared to 1950. Close to Disubungan river, Lamag, there is increase of open wetlands due to deforestation. Along Disulap river the same has happened. While the areas along the Pinacanauan were already deforested in the 50’s. People started living close to the river and cleared the area for cultivation. The Lamag area is no longer a forest(marsh), but a real wetland. This area was long ago an old river meander from the Pinacanauan flowing into Disubungan. After the river replaced itself the Lamag area became a marsh grown over by a forest and eventually logging made it an open wetland again. After 1972, deforestation continued and the area of wetlands increased even more. However, when we divide the wetland area in “natural wetlands” and “wetlands converted to agriculture”, we see a decrease in “natural wetlands”. Conversion to agriculture had already a big influence on the wetlands, leading to only small areas of natural open wetlands (blue in the figure).

4.1.3 Potential wetlands For the potential and actual wetlands a different approach was used. First a map is made with areas that can be a wetland based on topography, combined with a deforestation map (see figure 4.2). When we look at this map, it shows that most areas are cleared and because of that the area of potential open wetlands is big. But, due to the high population density and intense agriculture, most “natural open wetlands” are now agriculture. In the next section a description of the land use is given for some selected barangays to know where still open wetlands can be found and where the wetlands are converted to agriculture.

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Figure 4.1: Wetland maps for 1950 (top) and 1970 (below), blue is open wetland, orange is wetland converted to agriculture

20 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano

Figure 4.2: Potential wetland map, darker colors indicate higher relative chances

4.1.4 Land use Here the land use patterns will be discussed per barangay. When the land use pattern is known, this will give better insights on LUCC in relation to wetlands.

Current Land use San Mariano (municipality) Table 4.2: Land use in San Mariano and its barangays

Corn Rice Corn Banana Upland rice Peanuts combination Tobacco Fruit/vegetables Minanga 5% 54% 24% 0% 0% 7% 0% 10% Del Pilar 54% 18% 13% 4% 10% 0% 0% 1% Alibadabad 30% 63% 0% 2% 0% 6% 0% 0% San Jose 20% 52% 18% 4% 0% 6% 0% 0% Panninan 22% 55% 22% 0% 0% 0% 0% 0% Disulap 9% 61% 17% 3% 0% 8% 0% 3% Daragutan 6% 60% 22% 0% 1% 8% 2% 2% Sitio’s 8% 45% 6% 0% 0% 17% 0% 25% Total San Mariano 20% 51% 15% 2% 1% 6% 0% 4%

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The most abundant crop in San Mariano is corn, a cash crop. Furthermore rice and banana can be found on many places. Several fruit and vegetable crops are cultivated on smaller scales. There is also some upland rice, peanuts, tobacco and soya.

Minanga The land use around Minanga is mainly corn with some banana and only a few wet rice fields. Furthermore water melon can be found at similar places as the corn fields. Corn and water melon are cultivated close to the big river. Banana is cultivated at the high and steeper parts in the area. Rice is located further away from the river and not in the wetlands where they are to be expected. Only one of the farmers owned a rice field that was located in a small stream, which falls dry in summer season. According to the farmers the land close to the river (the main wetland around Minanga), is not suitable for wet rice fields because of the risk on flooding (see also conversion processes). So the (few) wetlands around Minanga are mainly affected by corn and water melon. Besides the big river and its direct surroundings, not much other wetlands can be found.

Del Pilar Del Pilar is one of the main rice areas of San Mariano. Rice is mostly combined with bananas and corn or peanuts. Close to the Disubungan river the most rice fields can be found. This complete flat area, which used to be a big swamp, is today completely converted to wet rice fields. This area is converted with help of the communal irrigation system (NIA) which started in the 60’s. West of Del Pilar, a more diverse land cover can be observed with a combination of the above mentioned crops. Rice is found here in the lower parts, surrounded by bananas and corn plantation on the relative dry parts. Peanuts are mostly interchangeable with corn fields. The rice fields which are not connected to NIA are irrigated by (fish)ponds, which are abundant in the area, either natural or manmade. In Del Pilar there is both wetland increase, deforestation and the manmade ponds, and wetland decrease, the NIA. Although the decrease due to the NIA project is much bigger.

Alibadabad The main crop in Alibadabad is corn, which is interchangeable with water melon or upland rice. Just like Minanga the risk of flooding close to the Disubungan river is too high for wet rice cultivation. However, on some distance from the river, there are many rice fields in the hilly parts. Most of the rice fields are upland terraces which are irrigated by pumps. But there are also some small springs/streams that are generally dry in summer season. People make smart use of these streams by damming them, which makes the area around the stream wet for the whole year and suitable for wet rice cultivation. This is sometimes done in combination with a fishpond. The area of these rice fields is slowly increasing because the fields are enlarged slowly each year. These wet rice fields are maintained with stagnating (dams) rain water which is directed from one field to another. There are not much natural streams to be found anymore in this area, almost every stream is converted to wet rice field or otherwise influenced by humans.

San Jose Around San Jose there is a mix of wet rice, banana and corn. Rice fields are in general smaller, because they are bound to the relative low and wet areas. Bananas have a relative small area because they are intercropped in the corn fields. The rice fields are affecting the wetlands most in this area. A lot of valley streams are dammed in advance of rice terraces, most of the times in

22 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano combination with a fishpond or so called SWIP (small water impounding projects). Approximately half of the valleys with rice fields contain a pond or SWIP. In the flatter areas the rice fields are located along creeks. The creeks are only used to irrigate the field in the beginning of the growing season.

San Jose, sitio Diwagden The hypothesis of decreasing wetlands due to rice cultivation seems to be quite good in this area. A lot of valley streams are dammed in advance of rice terraces, most of the times in combination with a fishpond. Also the lower river terraces in this area are mainly used for wet rice fields. But since the population pressure in this area is so low still, the effect on the wetlands is small too.

Panninan In Panninan not too many wetlands can be found. However, there are a few small creeks in the steeper parts, aside from the Pinacanauan river. Panninan has, just like San Jose, also a diverse land use pattern with mainly corn and some rice and banana. In the hilly parts the valleys and some springs are used for wet rice fields, the same process as in San Jose. About half of the streams in valleys are converted to wet rice fields by making dams (see photo). But there are also some creeks which are only used to irrigate the fields, but the creek itself remains intact. Closer to the river corn is found on the plains and next to the big river. Bananas are cultivated on the steeper parts and intercropped in the corn fields. Closer to Lamag, the amount of wetlands increases slowly, as do the rice fields.

Lamag This is the area of a big old river meander, but since the Pinacanauan river has become the main river instead of the Disubungan, the area changed to a forest marsh and later, after deforestation, to open wetland. Now it is used mainly for wet rice fields along creeks and in combination with big fishponds. Besides the fishponds there are also other wetlands to be found. This means that the area is influenced greatly by human management, but it can still be considered as a wetland area. Especially because the rice cultivation is not yet very intensive, although there are some big wet rice fields.

Disulap Also in Disulap, corn is the most abundant crop. Banana and rice are the other main crops, with bananas intercropped and only few real banana plantations. Rice is located close to the creeks or in small depressions. One example of such a depression in combination with a small stream is the rice field of a farmer who was using a small depression to let his carabow bathing, the clayey soil became impenetrable and the depression grew bigger. The farmer decided to make use of this and converted it to a rice field. In the surroundings of Disulap more of these “carabow” depressions can be found. There are also some creeks used to irrigate rice fields, but the creeks themselves are not converted. These rice fields have water stagnating soils which are fed with rain. The creeks are only sometimes (once a year) used to irrigate the fields when it is dry or when the field is renewed.

Chapter 4 – Results 23

Daragutan-East Corn and banana are also in Daragutan the most important crops. However, rice has a bigger effect then the percentages show. Half of the farmers have a wet rice fields, although they are very small. The corn is found close to Pinacanauan river, what used to be a river swamp. More to the east of the barangay, the area becomes more hilly with creeks. Here the rice fields can be found. The fields are located against the creeks with almost no space in between. At the higher parts bananas are cultivated on big plantations.

Dibuluan The surroundings of Dibuluan are quite undisturbed. There are some creeks and streams to be found, which vary greatly in size during the seasons. Because the area is close to the mountains and due to fast drainage, the smaller streams change to big streams after heavy rain. Occasionally a creek is converted to wet rice fields. The population density in this area is too low to have a serious influence on land use changes in relation to wetlands.

Binatug The area around Binatug is not as densely populated as one would expect on basis of its location. Although it is almost adjacent to Alibadabad and very accessible with good concrete roads, there are a lot of places that are undisturbed by people. In a southward direction a lot of creeks (and marshes) can be found, relative close to the big river. Only some corn/water melon fields are affecting the wetlands, but only occasionally. Most wetlands are still natural and not influenced.

Gangalan In contrast to Binatug, Gangalan is densely populated and there are not much wetlands anymore, except for the Disubungan. Only in the hilly parts there are a few very small (less than 0,5 m width) streams. Probably the area had some similarities with the Binatug area, but due to the intense cultivation of corn and subsequent distortion of the hydrological cycle, these have disappeared.

Land use changes in the last 50 years General: In the 50’s, the land use in San Mariano was almost totally forest with some wetlands and rice paddies. With the deforestation, the land use started to change. In the beginning more wetland was “created” by clearing. After the area was cleared, the land could also be used for agriculture. This means in general a decrease in wetlands. The Lamag area is a good example of the increase of wetlands due to deforestation. In 1950 it is still forest, as can be observed from a topographic map of that time. For 1970 however, the satellite images indicate a big wetland here. Also local people (the barangay captain and some farmers) say the area used to be a wetland in that period. Also the name itself implicate that it was a habitat for freshwater crocodiles, because Lamag means small crocodile in the local language. After some time, farmers started to cultivate this area and the wetland disappeared partly.

Crop changes In the last decennia there have been some changes in crop choice. In appendix C the changes that were found by interviewing the farmers are listed. Now a short summary of these changes will be given. The most recent change is the decrease in corn. The need for fertilizers and pesticides for corn is high and the prices of these products is increasing a lot recently. This makes corn not profitable anymore

24 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano and most farmers want to change their corn for new crops like upland rice or (since last few years) water melon. Also the area bananas has decreased a lot the last 10 years. Reasons for this are diseases or typhoons destroying the banana plantations. Some fields are just abandoned, while others are converted to corn or upland rice. Bananas are still grown, but now most of the times intercropped in corn fields or along the borders of corn fields. In the areas further away from the market San Mariano, peanuts used to be the main crop, but since the infrastructure has improved, the peanuts changed to corn. This occurred in the 80’s and early 90’s. Furthermore a small increase in wet rice fields can be observed in advance of corn fields or like in San Jose and Daragutan, out of forest or creeks and fishponds.

Conversion processes Wetland conversion is different for different types of wetland. The size of a stream is for example an important factor in the conversion process. The same is true for the slope of the wetland area and the accessibility. For this reason we should distinguish and describe different conversion processes for each type of wetland.

Swamps (Del Pilar/Lamag) The swamps around the Disubungan river close to Del Pilar are completely converted to wet rice fields. This area was probably a (forest) swamp before it was irrigated by the communal irrigation system (NIA) around the 70’s and 80’s. This NIA consist of a big scale irrigation system with canals, that slowly increased in area until the whole area was rice fields. In this case wetland is directly lost in favor of wet rice fields.

Marshes (Lamag/Binatug) In the area of Lamag, the land use is rapidly converting from degraded forest in combination with marshes to wet rice fields. Marshes are usually converted in a similar way as swamps: the wet rice fields are placed “inside” the marsh, which is drained and irrigated. So this is also a direct loss of wetlands. Sometimes also the creek or stream feeding this marsh is influenced, either direct or indirect.

Small streams (Alibadabad) Around Alibadabad a lot of agriculture can be found. A small part of this agriculture is wet rice cultivated in (very) small streams. These streams are directly converted to a wet rice fields, the farmers build a dam in the stream so that it will be flooded. The flooded area will be used to grow the rice. This is mainly done in streams which are smaller than 1 m in width and which would otherwise fall dry in the summer season.

Bigger streams and creeks (Panninan/Diwagden) When streams grow bigger and transport water also in the dry season, they become less suitable for direct conversion to wetlands. In this case the risk of flooding becomes too high according to the farmers. It is also more efficient to drain the water into surrounding fields instead of placing the rice in the stream or creek. Draining the creek into a rice field will only take one action per season to fill the rice fields, while in case of putting the rice fields inside the creek, constant management is needed to maintain the water table on top of the soil.

Hilly areas around wetlands: Rice terraces Actually this is not a wetland conversion, because wetland is not converted but some other land use is converted to wet rice fields with (fish) ponds. In areas were forest is cleared or degraded, some farmers start making rice terraces, mainly in combination with a pond. In this case wetlands are increased, because of these fish ponds. An example of this are the big rice terraces around Alibadabad to Disulap.

Chapter 4 – Results 25

Valley streams/SWIP’s (Diwagden/San Jose/Panninan) Valley streams are characterized by relative steep slopes at the sides of the stream and a relative steep gradient. This makes these wetlands only suitable for rice cultivation in case of terracing and widening of the stream. This can be clearly seen in the traject from San Jose to Diwagden. Almost all valley streams are terraced and widened to cultivate rice. However, in many cases this is done in combination with a SWIP or small lakes and ponds to maintain a good water table. Conversion of valley streams can both increase as well as decrease wetland area, because the streams are converted, but SWIP’s or small lakes and (fish)ponds increase the wetlands. This means that the net result of wetland conversion to rice can be positive for the total wetland area.

Big rivers Areas close to big rivers are converted to corn (and more recently also water melon) mainly. This has to do with the risk on flooding, especially in the rainy season. Wet rice is very sensitive to the water management, a flooding means no harvest. Corn is better adapted to flooding, it can easily survive a short period of flood and even if it causes damage to the crop, this is most of the time not very badly. So on the land use map we see mainly yellow colors along the sides of the big rivers Pinacanauan, Disubungan, Disulap and Catalangan. Only upstream, further away from the market San Mariano and more inaccessible, these corn fields are less pronounced, although still present. This can be explained by the fact that the rivers become smaller there and the risk on flooding decreases. However, this cannot be the only reason. The inaccessibility to the market and the lower population density play also an important role.

26 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 4.2 Drivers

4.2.1 Spatial characteristics To better understand the LUCC it is important to know the driving forces. In this part the spatial characteristics of an area that drive land use change are discussed.

Opinion of farmers (importance) on spatial factors The spatial characteristics that are important according to farmers can help explain the driving forces in an area. The importance of the spatial characteristics soil, slope, stream presence and accessibility have been quantified for different crops. The results are shown in table 4.2.

Table 4.2: Importance of the spatial factors per crop (ranging from1=low, to 4=high)

Soil Slope Stream Accessibility Corn (N=65) 2,86 (1,03) 2,02 (0.94) 2,66 (1,14) 2,43 (1,17) Rice (N=43) 2,74 (0,76) 1,93 (0,8) 3,56 (0,83) 1,74 (1,09) Upland rice(N=7) 2,71 (1,11) 1,86 (0,9) 3,14 (0,9) 2,29 (1,38) Corn combination/Fruit (N=9) 3,00 (1) 1,89 (0,78) 3,22 (0,97) 1,89 (1,17) Fruit (N=12) 3,08 (1,16) 1,83 (0,58) 3,08 (1,08) 2,00 (1,04) Banana (N=36) 2,89 (0,98) 2,50 (1,06) 2,19 (1,17) 2,42 (1,20)

For corn, the soil is the most important factor according to farmers, because it determines the fertility/need for fertilizer and hence the productivity/profitability of the crop. Because the price of inputs are very high at the moment, the profitability of corn is highly dependent on the need for fertilizers. On infertile soils, corn is not profitable anymore for this reason. The presence of a water body ranks second among farmers, while accessibility is also of some importance for corn. For the presence of a stream, the farmers did not give a clear explanation when asked for the reason why this is important for corn. Some farmers said it is important for themselves, because they need drinking water when they are working at the field. Others told it is for irrigation during drier periods. Accessibility is important because corn is a cash crop and a relative heavy crop to transport compared to other crops. When corn is yield, there is a big volume of corn that needs to be transported at once. This makes it difficult to transport it compared to a crop as banana, which can be yield every 2 weeks and be transported in smaller amounts. When the spatial factors for rice are compared, water is the most important factor, as expected for the irrigation of wet rice fields. However, also the soil plays an important role, both for its texture as its fertility. The soil texture should be fine to clayey according to most farmers. The productivity of rice varies a lot with soil fertility. Rice is not a cash crop, but used by the families for their own food, so accessibility is not important. Only the accessibility of the field to the farm has some importance. Rice fields need a lot management and for that farmers want to have their rice fields close to their house. Slope is not important because the people know how to make rice terraces or how to irrigate their fields in a proper way. Upland rice shows a similar importance for the spatial factors as wet rice. The main difference is the accessibility. This can be simply explained by the fact that upland rice is sold instead of used for their own. When a crop is sold to the market, the market has to be accessible. Combinations of corn with fruit/upland rice or mono fruit fields, require a good soil and some presence of water to get a high productivity. However, for crops like water melon, the fertility is less important. Most farmers change their corn fields to water melon because corn needs higher inputs than melon. Fruit trees can grow on even the steepest slopes, so this is not of importance. Accessibility is not important because it can be both used as a cash crop as for own use.

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Also for bananas the soil is of importance to get high yields. Slope ranks second. Farmers want bananas on the steeper slopes, because no other crops than banana (or fruits) can be cultivated there. But also because it has to be difficult to reach for animals. Some farmers said carabows of the neighbors will eat their bananas if the banana field is easy to reach for these animals. Bananas are cash crops, but because it is quite easy to transport, accessibility is not that important.

Soil(fertility/texture) Soil has an influence on the land use because it determines the suitability of an location for a specific land use. In that way it is an important driver. The distribution of the different land uses over different texture and fertility classes helps understanding the driving processes.

Table 4.3: Distribution of the texture classes per crop

Texture class Corn Rice Banana Combination Fruit Upland rice Clay 8% 19% 1% 0% 6% 0% Fine 45% 30% 48% 36% 24% 50% Sand 30% 34% 23% 26% 17% 8% Coarse 13% 13% 24% 12% 1% 25% No Data 4% 4% 4% 25% 52% 17%

Looking to the relation between texture and crop choice, corn and banana show a similar distribution. They are both found on fine to sandy soils. However, banana is a bit more abundant at the coarser soils and corn on the other hand on the more clayey soils. Corn is simply not suitable to grow on soils with many stones, while banana trees can be easily grown on stony soils. Wet rice is also mainly found on fine and sandy soils, but tends more to clay then corn and banana. It is unexpected that 34% of the rice fields are on sandy soils, because it is more difficult to create a wet field on sand instead of clay. One reason can be that clay soils are in general closer to the big streams and in the lowest areas, where there is a high risk of flooding. Rice is very sensitive to flooding so farmers choose to locate their rice fields further away from the big rivers, where the soil becomes more sandy. The rice terraces, where water pumps are used to irrigate the fields, are also a bit sandy. Fruit needs finer texture soils and cannot be grown on coarse soils with stones. Upland rice is found in both fine and coarse textured areas. The combination fields show, as can be expected, an combination of the preferences of corn and fruit/upland rice.

Table 4.4: Distribution of fertility per crop (1=low, 5=high)

Fertility class Corn Rice Banana Combination Fruit Upland rice 1 8% 15% 0% 4% 6% 8% 2 0% 5% 0% 7% 0% 0% 3 22% 18% 63% 7% 3% 33% 4 31% 29% 13% 11% 16% 0% 5 31% 32% 19% 47% 23% 58% No Data 7% 4% 4% 25% 52% 0%

More than half of the corn fields is on the more fertile soils and almost no corn is on infertile (red) soils. This has to do with the need for fertilizers for corn and the high costs related to this. Corn is not profitable on less fertile soils. For rice the pattern is more equally distributed because rice is not so dependent on fertilizers and because it is for own use. Bananas seem to have the lowest need for a fertile soil, it is mainly found at soils with average fertility. Fruits, upland rice and combinations with corn are almost only on highly fertile soil.

28 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano Slope Slope also determines the suitability for different land uses, so the distribution for the slope of the different land uses has to be known.

Table 4.5: Distribution of slope per crop (1=flat, 5=steepest)

Slope class Corn Rice Banana Combination Fruit Upland rice 1 18% 57% 2% 10% 11% 8% 2 15% 17% 7% 77% 30% 0% 3 40% 9% 47% 3% 12% 58% 4 22% 11% 32% 10% 13% 0% 5 3% 0% 8% 0% 0% 33% No Data 3% 6% 4% 0% 35% 0%

The slope distribution for corn is on the middle slopes with some fields on flatter areas and some on steeper. Rice is concentrated on the flatter slopes and terraces. The bananas, which can be grown on all slopes in principle, are more on the hilly and steep parts. As mentioned before, this is because no other crops are suitable for steep slopes and because bananas need some kind of inaccessibility. Fruit trees are, although they can easily be grown on steeper slopes, mainly found on flatter areas. Upland rice is especially cultivated on rolling (middle slope) areas, just like corn. Corn and upland rice are also easy to switch according to farmers.

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4.2.2 Temporal characteristics Accessibility (farm-field) Accessibility can be a driver for LUCC because some crops need more management then others or are easier to transport. The mean travel time is a good indication of the accessibility. The travel times per crop are given in table 4.6.

Table 4.6: Travel times per crop in minutes

Std. Crop Mean travel time Deviation Corn (N=96.8) 42.46 67.49 Rice (N=36,75) 38.24 59.45 Banana (N=28,7) 94.62 126.95 Combi (N=12,1) 29.34 23.01 Fruit (N=8,65) 16.88 22.20 Upland rice (N=3) 25.00 28.06

Corn and rice have both a travel time of around 40 minutes. Corn and rice fields need to be managed very carefully, what makes it necessary to have these fields relative close to the farm. Bananas are relative far away at the more inaccessible areas. The way of harvesting makes it possible to have banana plantations further away. Contrary to corn and rice, bananas can be yield every 2 weeks in relative small amounts. The harvest can be transported with help of simple carts and a carabow, while for rice and corn bigger transport means are necessary. Fruits on the other hand are very close to the farm. This is supported by statements from farmers. Fruit should be close to the house, especially when it is for own use (like a home garden) and to prevent stealing or destroying by animals.

Ethnicity Different cultures are used to cultivate different crops. Table 4.7 shows what crops are cultivated by the ethnic groups in San Mariano.

Table 4.7: Crops cultivated per ethnic group

Ethnicity Corn Rice Banana Combi Fruit Upland rice Ilocano 34% 15% 11% 5% 5% 30% Ilocano/Ibanag 28% 3% 12% 5% 0% 52% Ibanag 42% 10% 5% 3% 0% 40% Ifugao 9% 10% 0% 0% 1% 79%

The Ilocano’s are the main wet rice cultivators with 15% of their crops being rice. The second big ethnic group, the Ibanag, cultivate corn in combination with upland rice and less wet rice. The Ifugao, the third ethnic group based on cultivated land, grow mainly upland rice and a reasonable amount of wet rice, but less corn. There are also some other groups, but these cultivate only a very small amount of the agricultural land in San Mariano and are for that reason not included in this table. These relations between ethnic group and crop choice correspond with the cultural backgrounds that the Ilocano and Ifugao are the main rice cultivators and the Ibanag the corn farmers.

Landownership In table 4.8 the type of landownership per crop is given.

30 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano Table 4.8: Landownership per crop

Type of ownership Corn Rice Banana Combi Fruit Upland rice Land title 35% 39% 29% 44% 20% 17% Stewardship 5% 2% 6% 0% 0% 0% Declaration 10% 5% 6% 8% 6% 25% Informal 39% 26% 49% 40% 54% 17% Tenant 9% 2% 1% 8% 20% 42% Process to land title 2% 25% 9% 0% 0% 0%

In general the landownership is the same for all crops. Only rice is found more on areas with a land title or process to land title. This could be explained by the fact that there is an increase in wet rice fields, in fields which were previous not cultivated at all. The people with these fields (3% of total area) are now in a process to get a land title. Fruit is also an exception with more than half of the area is informal. This has to do with the fact that fruits are grown close to the house normally and these areas have no formal state.

Knowledge and other drivers for LUCC Some farmers explained during the interviews that they grow specific crops, because they know how to manage it. They simply don’t know how to grow other crops that need other managing techniques. This also means that most of the time they more or less copy what their neighbors are doing. For example, when a new farmer migrates to the area, it is likely that he uses different managing techniques for his crops than the local people are used to, due to a different (cultural) background. If he knows how to make wet rice terraces, while the other people don’t, and it works good, then the other farmers will probably copy this. This was the case in Panninan where one farmer from another location started to cultivate wet rice in that area, but also farmers in other barangays were telling that they most of the times just copy their neighbors. Many farmers mention budget as a restriction in their crop choice. Most of the farmers are simply not rich enough to afford all materials to grow the crops they would want to grow. For example, some farmers want to create wet rice terraces in upland areas, but in order to do this they need a water pump. So they are limited in their cultivation options by their budget. A substantial part of the farmers in San Mariano also have depths with corn traders. This forces them to keep growing corn, even when it is almost not profitable anymore (too high inputs). As long as they have depths with their traders, the trader can decide what they have to cultivate and for what prices. Only when they can break this cycle of loans from traders, they can start cultivating other crops. As mentioned before, along the rivers and the bigger streams, mainly corn can be found as land use. This is because corn is less sensitive to flooding than other crops, like rice. Rice fields are completely destroyed after even small flooding, while corn can handle this much better. So the risk of a flood is an important driver for land use. Inaccessibility (or market forces) has a complicated influence on LUCC, and for that reason on wetland conversion. When an area is close to the market, there will be found other crops compared to an area far away from the market. Crops with a high bulk density or volume are difficult to transport over big distances. That’s why in the remote areas with bad roads, mainly peanuts can be found. As soon as there are better roads emerging, the farmers change to corn and sometimes rice. Inaccessibility also increases the need for self-sufficiency. For example the farmers in a remote place as Diwagden need to grow their own rice, because they are not able to buy rice in shops. Since the area is far away from the market (because of distance and bad infrastructure), the people have the need to grow their own rice. While people in the more accessible areas can also buy rice in the market.

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4.3 Potential habitats

4.3.1 Validation of potential wetland map To get an indication of the accuracy of the potential wetland map, the average relative chance per data point is calculated: 0.25 (0=min, 1=max, N=35, std. dev.=0.26). Although this relative chance is not very high, it does not directly mean the map is not good enough. Some of the data points with a low relative chance are in fact very close to cells with high relative chances. This can partly be explained by the inaccuracy of the GPS device and an inaccuracy of the DEM. When a map with all rivers and streams is layed on top of the potential wetland map, and also a map showing the wet rice fields, it can be observed that the pattern of wetlands is in fact very clear from the potential wetland map. All the main rivers and their swamps also have a high value in the potential wetland map. The Lamag area has also relative high values. Looking at other areas that have high relative chances, it can be observed that in many cases there are some wet rice fields there.

Figure 4.3: Validation of the potential wetland map

32 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 4.3.2 Land use threats For the protection of crocodile habitats, and thus wetlands, it is important to know which crops are threatening the wetlands most. Rice was assumed to be the biggest threat for the wetlands. However, the total area of rice is very small compared to the other main crops, corn and banana. When we compare the potential wetland map and the locations with rice fields, it is indeed clear that rice is a direct threat for wetlands. Rice is only found at locations where there is also a high relative chance to find a wetland. Especially in the areas of old river meanders, swamps and close to small streams in the more hilly parts (the small red dots in the middle of the map). That rice is at the same locations as wetlands does not mean that wetlands are disappearing. That depends on the conversion processes as discussed before (section 4.1). Corn on the other hand was not expected to be a threat. However, also corn seems to be threatening the wetlands. Although corn is not exclusively located near wetlands, as is rice, but still it is almost near all wetlands. Bananas are not located close to wetlands and are for that reason not a threat for wetlands.

Figure 4.5: Rice as a threat for wetlands

Chapter 4 – Results 33

Figure 4.6: Corn (top) and banana (below) as threats for wetlands

34 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 4.3.3 Population density/Accessibility An accessibility map (fig 4.4) to the market of San Mariano is a good indication for the habitat suitability related to population density. The area becomes more inaccessible and less densely populated to the southeast and at the same time more suitable as crocodile habitat.

Figure 4.4: Accessibility map to the market (measured in distance)

4.3.4 Awareness Areas with people that are aware of crocodile protection are expected to be more suitable as habitat for juveniles. The barangays with a low awareness are the ones were no seminars have been given by the Mabuwaya foundation in the past. In other barangays where seminars have been given to local people, these people are also aware and more willing to protect the crocodile. Table 4.9 shows the percentages of people that are aware in some barangays.

Table 4.9: Awareness of crocodile protection for the municipality and per barangay

Not Location aware Aware San Mariano (N=81) 26% 74% Minanga (N=10) 20% 80% Del Pilar (N=12) 33% 67% Alibadabad (N=12) 33% 67% San Jose (N=12) 25% 75% Panninan (N=7) 43% 57% Disulap (N=12) 8% 92% Daragutan (N=11) 36% 64% Sitio´s (N=5) 0% 100%

Chapter 4 – Results 35

4.3.5 Connectivity The current crocodile habitats in the study area are Dunoy and Diwagden in the northeast of the area. Close to Panninan, but just outside the study area, there is another crocodile habitat. There are some stories of people telling that there are also crocodiles in Lamag again, but there are no official observations. Only one crocodile has been caught in this area recently and transported to another area. Fig.. shows the areas that are the furthest away from the current crocodile habitats. A habitat along the Disubungan would increase the connectivity of the habitats.

Figure 4.7: Distance to crocodile habitat: light is close to a current habitat, dark is far away

36 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 5 Discussion

5.1 Interpretation and comments on the results

5.1.1 LUCC in relation to wetlands LUCC in San Mariano has resulted in a highly deforested area with a lot of agriculture and some wetlands. But this land use pattern has not always been there. Before 1950 the area was still primary forest with some small open wetlands. In the 60’s and 70’s deforestation started, initially leading to an increase of open wetlands as can be seen on the wetland maps. But at the same time the population was growing and more land was needed for agriculture. To fulfill the increasing demand for agriculture, wetlands were converted. Till the logging moratorium in 1992 commercial logging companies increased the speed of deforestation. At the same time the population and the demand for agricultural land kept growing, resulting in a high pressure on the wetlands. So deforestation “created” open wetlands in the first place, followed by a conversion to agricultural land. The conversion process determines whether wetland decline occurs or not. In most cases of wetland conversion, the wetland itself does not disappear. Rivers and bigger streams are not directly converted to agriculture, only the areas surrounding these rivers or streams. Only swamps, marshes and valley streams are directly affected, because they become rice fields. But also here wetland decline is not necessary. SWIP’s and (fish)ponds can partly make up for the loss of wetland. Compared to 1950, the LUCC has changed from primary forest with some small wetlands along the main rivers to a cleared area with mainly agriculture and some wetland inclusions. In the 60’s and 70’s there has been an increase in wetlands due to the deforestation (Lamag and Disulap river) in combination with a small agricultural pressure on the wetlands. However, after this period of increase in wetland, wetland conversion becomes more and more important due to the demand for agricultural land. The main change concerning wetlands is their distribution through the area. From relative big wetlands in the period 1950-1980, to small inclusions of wetlands in agricultural land. Lamag remains the only big open wetland area. However, also here wetland conversion occurs at the moment. In the more inaccessible areas, like Diwagden and Dibuluan, small wetlands can still be found. Because these sites are not suitable for agriculture, there is not so much pressure for wetland conversion. The population density is still very low, but the population grows so fast in San Mariano that even these more inaccessible areas are becoming cultivated. This happens only at a very small scale, but still it has an impact on wetlands. These people need to be self-sufficient, because they are too far from the market. Rice is their main food, so they need land that is suitable to grow rice: the small wetlands. As long as this happens on a small scale, it will not have a very big influence on the wetland area. But when the population keeps growing, it will seriously damage the wetlands. The wetlands around Disulap and Binatug are quite undisturbed, which is remarkable because these areas are so accessible. Around Disulap there is a lot of agriculture, but this did not directly affect the wetlands (see conversion processes). Binatug is one of the few locations where agricultural pressure on the land is not so high. There is no clear reason for this. Gangalan on the other hand, which is adjacent to Binatug, is completely the opposite. Here is the agricultural pressure so high that almost no wetlands can be found anymore. Only some old streams can be found where now rice terraces are located. The swamps along Disubungan river are all drained for corn and are now dry. Further upstream from the Disubungan, the big wet rice fields of Del Pilar are found. Although the majority of the wetlands have been converted to wet rice fields by big irrigation systems (NIA), there are still some wetlands. Between the rice fields there are also some fishponds for irrigation of these rice fields. The wetlands along the Pinacanauan river were already partly affected by agriculture in 1954 as can be seen on the topographic map. Half of the area was already rice paddy in that time. This influence has only increased and especially downstream, there are almost no wetlands that are not converted.

Chapter 5 – Discusion 37

But at the moment it are not rice paddy’s, but mainly corn. Around Panninan there are still some creeks and valley streams. Because of the low population density these wetlands have not yet been converted. The same can be seen in San Jose, although here the influence of agriculture is bigger and more wetlands are converted. In these areas there is a heterogeneous land use with corn and wet rice close to the wetlands and banana on the more hilly parts. The areas close to San Mariano have had too much influence of agriculture and almost no natural wetlands can be found there. Looking at the general pattern where natural open wetlands are located, there seems to be a “belt” with small wetlands from Dibuluan to Panninan, including San Jose/Diwagden, Del Pilar and Lamag. To make the pattern complete, Binatug and Disulap should be included too. The areas closer to Centro are too much influenced by agriculture and further southeast the area is topographically not suitable to have wetlands. From the description of the land uses it becomes clear that corn and rice are the main threats for wetlands. Banana is located at steeper parts or intercropped in corn fields, but never as a monoculture close to wetlands. Close to San Mariano Centro, corn can be considered the only threat. Rice fields are rare, except for the rice terraces with water pumps. Rice becomes more abundant in the remote areas and because of its need for water, it is a direct threat for wetlands. In the marshes and swamps of Lamag and Del Pilar, it is the main threat, while in the other remote areas corn is still the biggest threat because it is much more abundant than rice.

5.1.2 Drivers Knowing the driving forces of LUCC can help protecting the habitat of the Philippine crocodile. From the description of the land use we know that corn and rice are the relevant crops, considering wetland conversion. For that reason we will focus here on the driving forces for these two crops. Fertility of the soil is a very important driver for corn. Not only the farmers indicate fertility as most important factor, also the distribution of corn is predominantly on highly fertile soils. This can be related to economic reasons. Corn is a cash crop and the people depend on it for their living. When the productivity is too low because of a low soil fertility, the profitability is too low. Accessibility is another driver for corn. The corn fields should be relative close to the farm and the infrastructure to the market should be suitable to transport the yields. Fields with a high slope are not suitable for corn, the more flat, the better. However, farmers do not think slope is important for corn. The distribution over the different slopes reflects this: mainly on the middle slopes, but almost nothing at the very steep parts. For rice, the presence of a stream is almost essential. Only with help of a water pump rice fields can be created at drier places. Although farmers say a good soil is important for wet rice, this is only partly confirmed by the distribution of rice to the different soils. A good soil for wet rice needs a high clay content to create a layer of stagnating water. However, rice is abundant on sandy soils. On the other hand, rice is mainly found on fertile soils, what confirms the need for a good soil. Probably the need for a high fertility makes up for the extra efforts that are needed to create a wet field in sand. Furthermore, rice should be close to the farm. Traders and the budget of farmers have an influence on land use. The budget limits the options of a farmer. A farmer who has loans from a trader, is dependent on this trader. He can not choose the crops he want to grow. This makes it almost impossible for a farmer to change his crop. A rich farmer would be able to invest in his land and start cultivating different (new) crops. In fact, corn would be less abundant in the area when farmers are not dependent on corn traders. Knowledge of cultivation techniques influences the LUCC a lot. A farmer that does not know how to manage a specific crop can not cultivate this crop. The migration of people changed the crop choice at some locations in the study area. In the most remote areas, the accessibility to the market is an important factor in land use. These areas are very inaccessible and that inaccessibility creates a need for self-sufficiency. So all farmers need a rice field since they are not able to buy it in a shop. That is why there is an increase in small rice fields in the remote areas. Another reason for increase in rice fields is the lower risk of flooding.

38 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano Close to the rivers and bigger streams, the land use is dominated by corn. Corn is less sensitive to flooding than rice, so farmers decide to only grow corn at those locations while in remote areas the risk of flooding is lower and rice can be cultivated. Considering the current wetlands, the ones with a high fertility and a clayey to fine texture are most likely to be converted to corn and rice. An option to prevent this is learning farmers how to cultivate other crops. In that way they have more options and are less dependent on only rice or corn for their living. An experiment with fruit trees in one of the more remote areas showed that this is an option, the refo-project. The main underlying cause for wetland conversion is population growth. Without the growing population, there would be no demand for agricultural land. Trying to stop this increase in population would help protecting the remaining wetlands, although this is difficult to achieve.

5.1.3 Potential habitats The potential wetland map clearly shows the areas with a high topographic suitability to be wetland. Although the relative chance distribution is far from perfect, the patterns of wetland locations are very good. The potential wetland map itself is not enough to allocate potential crocodile habitats, because of the human influence on the land. From the description of the land use and conversion processes in the study area, we know that there is a “belt” of open wetlands from Dibuluan to Panninan plus the wetlands around Binatug and Disulap. Mapping the accessibility to the market is a good way to show the suitability of an area to be not converted. A map showing the distance to current habitats, can show the places that increase the connectivity of the habitats. So the most suitable areas for a crocodile habitat are located far away from San Mariano, to the southeast, because of accessibility. But also somewhere in the middle of the study area to connect the current habitats. From this point of view Lamag and Del Pilar are interesting. This would connect the habitat just outside the study area with Disubungan river. When there is also habitat in Binatug/Disulap or San Jose, this would increase the connectivity of all the habitats in San Mariano. Disulap is very interesting for the connectivity, because here the Disubungan and Disulap river come together and more downstream also Catalangan river. Corn and rice are both threats for potential habitats. So new habitats are preferably wetlands surrounded by soils with low fertility, because rice and corn are located in the most fertile areas. Also the wetlands in more stony areas have a lower chance to be converted to agriculture. A good example of this is the crocodile habitat in Diwagden (photo): a limestone area with incised streams and some floodplains. The area is inaccessible and not very suitable for agriculture. Making an awareness map was not possible, but still it has to be considered for the location of potential habitats. Good management of the land and cooperation with farmers can create new habitats. Around Del Pilar and Lamag some fishponds and streams can serve as new habitat for the crocodiles. Or rice fields can be converted back to wetlands. That this is not necessarily bad for a farmer is proven in Dunoy where a rice field is converted back to wetland and now serves as habitat.

Chapter 5 – Discusion 39

5.2 SWOT

5.2.1 Data of the maps The reliability of the used data is important for the accuracy of the wetland maps. For that reason this data need to be discussed. The scale (1:250000) of the topographic map of 1954 is a problem. A map of this scale should not be used in a study at the micro level. But with the knowledge of deforestation borders (Nagtegaal, 2007) and the stories of farmers, it can be said that this map gives a good indication of the wetlands at that time. However, it should be used with acuity. The satellite image interpretations, used to find the wetlands in the 70’s, only give a general indication of wetland areas, but contain much errors. An aerial photo interpretation improved this wetland map in such a way that it can be used at the micro-level. The areas that were classified as wetland were all checked on the aerial photos and some wetlands that were added. A digital elevation model with a high resolution (15 m) made it possible to create a very detailed potential wetland map. The disadvantage of this map is, that it shows the locations where open wetlands can be found, but not whether they are converted to agriculture or not. So additional data about the land use at the micro level is needed to know where the remaining wetlands can be found.

5.2.2 Interviews One of the strong points of the interviews is that they give good information about the land use and its drivers on the field level. Farmers can give good information about how they use their land and describe the land use pattern at the micro level. Because the research is focused on the micro-level, the driving forces for wetland conversion could be found. A disadvantage of using interviews to find driving forces is the reliability. Sometimes farmers do not give all information. When farmers are asked what crops they cultivate, they “forget” a crop. Or they only mention the crops on fields that they own and not the ones that they cultivate as a tenant. Questions about the reasons why they cultivate a specific crop caused distrust with some farmers, because they feel intimidated by these kind of questions. Also miscommunication can cause difficulties during the interviews, without knowing. The Filipino farmers are not used to be interviewed for scientific research and most of the time they don’t understand why these questions are asked. This in combination with a culture difference can make good communication difficult. To prevent this, the questionnaire was first intensively discussed with the interpreter to make sure all questions are clear and she knows why the questions are asked. In this way unnecessary miscommunication between researcher and interpreter is avoided. After this, the questionnaire was first tested a few times in the field, so that it could be improved and the interviewing technique adapted to make it easier for farmers to answer.

5.2.3 Applicability The underlying ground for this research was to know more about freshwater-wetland conversion and to apply this knowledge to create new habitat for the Philippine crocodile. So first of all this report should give a clear overview of the LUCC in relation to wetlands, and its drivers, in the study area of the last 50 years. This is done by creating wetland maps for 3 different times. In this way the change in wetlands is visualized. In combination with the description of the land use at the field level for several barangays throughout the area, a lot of information is available about LUCC at the micro- level. This information can be used by decisions about where to “create” new crocodile habitats. The data points obtained during the validation of the wetland map is also useful by the decision for the location of new habitats. From 35 points land use data and a photo are available. The current wetland map itself shows very good the areas where wetlands can be found. Together with the knowledge about the driving forces for wetland conversion, the suitable areas for potential habitats can be found. The method of finding wetlands can be applied in other areas too. It is a simple method that only requires a digital elevation model. Only the thresholds for altitude, slope, and relative low areas have to be adapted to the new situation.

40 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano 6 Conclusion The hypothesis about LUCC in San Mariano was that wetlands are disappearing due to agriculture, especially wet rice cultivation. This is indeed the case, at some places wetlands are converted to rice fields. However, this is only on a very small scale. Corn has had a much bigger influence on the wetlands, although less direct because the stream or river remains intact. When the current situation is compared with 1950 or 1970, it can be argued whether there is a decrease in open wetlands at all. Because in 1950 almost the entire area was forest and only around the Pinacanauan and Disubungan river some open wetlands can be found. It is difficult to estimate if there is a net decrease or increase in wetlands. The main drivers for wetland conversion are not wet rice fields as expected and infrastructural expansion. Infrastructure does not seem to be a driver at all. Conversion of wetlands to wet rice fields occurs only on a small scale. The spatial factor soil on the other hand is one of the driving forces. The drivers for wetland conversion are much more complex than expected in advance. Factors of important are: risk of flooding, knowledge and self-sufficiency with a fast growing population being the underlying cause. The last research goal was to make a map that indicates potential habitats. It is possible to make a map that shows potential wetlands, but this is not yet a map of crocodile habitats. Many of the potential wetlands are already converted for agriculture. To map the wetlands that are not yet converted is not possible with just a DEM-analysis. However, in combination with the driving forces for wetland conversion, an advice can be given for potential habitats. But field checks are still necessary before deciding where to create the new habitats.

Chapter 6 - Conclusion 41

42 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano Apendix A: Interview General questions - What is your name? - What is your age? - Gender - What is your ethnic group? - Where were you born? - When did you start to live here?

Current activities - Are you the owner of the land you cultivate (land title, stewardship, tax declaration, tenant or informal) and what is the area? - What crops are grown? - What is the area of land per crop? - Do you irrigate your crops? - Are you planning to grow other crops in the future?

Past activities - Which crops have you cultivated in the past? - What was the area of land per crop?

Other activities - Are there other activities you do that generate income and which one?

Location characteristics - Why do you cultivate the crops on the specific locations? - What is your travel time to the fields? - Can you order the following factors in importance for the choice of your crop location? - River or stream presence - Soil type - Slope - Accessibility

Economic - Do you sell your crops to the market, trader or for own us? - Is changing profit of a crop a reason to start cultivating other crops?

Social - Is the crocodile protected by law? - What is your opinion concerning crocodile protection? - Are there crocodiles on your land? - Do you consider crocodile protection in your planning of cultivation?

Appendices 43

44 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano

Appendix B: Land use per barangays San Mariano (municipality) Rice Corn Banana Upland rice Peanuts Combi Tobacco Fruit Total area 37,8 98,8 29,55 3 2,75 12,1 0,5 8,65 average farmer 0,47 1,24 0,37 0,04 0,03 0,15 0,01 0,11 Percentage 20% 51% 15% 2% 1% 6% 0% 4%

Minanga Rice Corn Corn/melon Banana Corn/veg. Melon Mango Area (ha) 1,60 16,10 1,30 7,20 0,80 2,50 0,50 Percentage 5% 54% 4% 24% 3% 8% 2% Average farmer 0,16 1,61 0,13 0,72 0,08 0,25 0,05

Del Pilar Rice Corn Upland rice Banana Peanuts Vegetables Area (ha) 13,4 4,55 1 3,25 2,5 0,2 Percentage 54% 18% 4% 13% 10% 1% Average farmer 1,12 0,38 0,08 0,27 0,21 0,02

Alibadabad Corn Rice Upland Rice Corn/melon Corn/upland Rice Area (ha) 17,75 8,35 0,5 1,2 0,5 Percentage 63% 30% 2% 4% 2% Average farmer 1,48 0,70 0,04 0,10 0,04

San Jose Banana Rice Corn Corn/upland rice Upland rice Area 4,95 5,5 14,5 1,8 1 Percentage 18% 20% 52% 6% 4% Average farmer 0,41 0,46 1,21 0,15 0,08

Panninan Rice Corn Banana Area (ha) 4,25 10,5 4,2 Percentage 22% 55% 22% Average farmer 0,61 1,50 0,60

Disulap Upland rice Corn Corn/upland rice Banana Rice Fruit Area (ha) 0,5 12,1 1,5 3,4 1,75 0,5 Percentage 3% 61% 8% 17% 9% 3% Average farmer 0,04 1,01 0,13 0,28 0,15 0,04

Appendices 45

Daragutan-East Corn Rice Vegetables Tobacco Banana Peanuts Corn/melon Area (ha) 15,3 1,55 0,45 0,5 5,5 0,25 2 Percentage 60% 6% 2% 2% 22% 1% 8% Average farmer 1,39 0,14 0,04 0,05 0,50 0,02 0,18

46 S.W.P. Nysten – Conversion of freshwater wetlands: Micro-level land use changes and crocodile conservation in San Mariano Appendix C: Crop changes per barangay: Minanga, total area 30 ha 1990: 3 ha peanuts changes to 1,5 ha banana and 1,5 ha corn. 1992: 1 ha peanuts changes to 1 ha corn, from which 0,2 ha will change to rice in 2000. 2007: 1,5 ha corn changes to 1,5 ha water melon 2008: 1 ha corn changes to 1 ha water melon; 0,4 ha corn changes to 0,4 ha rice. Another 0,5 ha peanuts changed to corn, but the year is unknown.

Del Pilar, total area 24,9 ha 1991: 1 ha corn changes to 1 ha rice. 1999: 0,5 ha corn, 7,8 ha peanut and 0,9 ha banana changes to 9,1 ha rice. 2000: 0,5 ha forest changes to 0,5 ha banana. 2005: 0,4 ha upland rice changes to 0,4 ha corn. 2006: 1 ha corn changes to 1 ha rice. 2007: 1 ha banana changes to 0,5 ha corn and 0,5 ha upland rice. Recently 2,7 ha forest changed to 1,2 ha rice and 1,5 ha corn.

Alibadabad, total area 28,3 1995: 2 ha corn changes to 2 ha rice. 2003: 0,5 ha sical changes to 0,5 ha corn; 0,5 ha corn changes to 0,5 ha rice; 1 ha banana changes to 1 ha corn. 2004: 0,5 ha corn changes to 0,5 ha rice. 2005: 1,7 ha corn changes to 1,2 ha corn/melon and 0,5 ha rice 2007: 2 ha upland rice changes to 2 ha corn; 0,25 ha corn changes to 0,25 ha upland rice; 2 ha banana changes to 2 ha corn. 4,5 ha soya changed to 2,25 ha corn and 2,25 ha rice.

San Jose, total area 27,75 80’s: 1 ha forest changed to rice. 1985: 2 ha upland rice changed to 1 ha corn and 1 ha banana. 1986: 0,5 ha upland rice changed to 0,5 ha rice. 1987: fishpond/creek changed to 0,5 ha rice; 1998: fishpond changes to 1 ha rice. 1999: 2 ha banana to 2 ha corn. 2001: 3 ha forest changes to 2,5 ha corn and 0,5 ha banana. 2004: 2 ha banana changes to 2 ha corn; 2,25 ha forest changes to 2 ha corn and 0,25 ha banana. 2008: 0,5 ha banana changes to 0,5 ha rice; 0,75 ha corn changes to 0,75 ha upland rice. 0,5 ha peanut changed to 0,5 ha corn.

Panninan, total area 18,95 ha 1989: 0,5 ha corn changes to 0,5 ha rice; 1 ha banana changes to 1 ha corn. 2001: 3 ha banana changes to 3 ha corn. 2005: 0,5 ha corn changes to 0,5 ha rice. 2006: 0,75 ha corn changes to 0,75 ha rice. 2007: 2 ha corn changes to 2 ha rice.

Disulap, total area 19,75 ha 1984: 0,6 ha peanut changes to 0,6 ha corn. 1985: 1 ha banana changes to 1 ha corn.

Appendices 47

1998: 0,5 ha upland rice changes to 0,5 ha fruits. 1999: 1 forest changes to 1 ha banana. 2000: 2 ha banana changes to 2 ha corn. 2004: 0,5 ha upland rice changes to 0,5 ha banana. 2006: stopped corn field. 2007: 2 ha banana changes to 2 ha corn; 0,25 ha corn changes to 0,25 ha rice. 2008: 0,5 ha corn changes to 0,5 ha rice.

Daragutan 1986: 0,5 ha banana changes to 0,5 ha rice; 1 ha forest changes to 0,25 ha peanuts and 0,75 ha corn. 1989: 0,3 ha forest changes to 0,3 ha rice. 1993: 1,5 ha upland rice changes to 1,5 ha corn. 1994: 3 ha wild banana changes to 0,25 ha banana and 2,75 ha corn. 1999: 0,25 ha corn changes to 0,25 ha rice; 1,6 ha banana changes to 1,5 ha corn and 0,1 ha fruit. 2006: 6,5 ha banana changes to 6,5 ha corn. 2007: 0,25 ha banana change to 0,25 ha rice; 0,25 ha corn changes to 0,25 ha rice.

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