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The Jane Goodall Institute Tanzania

Watershed Assessment Greater Gombe Ecosystem, Tanzania

30 August 2007

Thomas DeMeo USDA Forest Service Regional Ecologist Pacific Northwest Region 333 SW First Avenue Portland, OR 97204 tdemeo@fs.fed.us

Carol E. Purchase USDA Forest Service Forest Monitoring and Evaluation Coordinator / Hydrologist Medicine Bow-Routt National Forest Thunder Basin National Grassland cpurchase@fs.fed.us

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Objectives Ecosystems consist of interrelated climate, water, soil, geology, vegetation, and wildlife attributes, functioning together in complex ways. The objective of our visit was to assess the watersheds of the Greater Gombe Ecosystem (GGE), with emphases on the conservation and restoration of its soil and water resources, and how reforestation efforts could be made more quickly and more effectively. These objectives in turn support the restoration goals of providing for the long-term habitat needs of chimpanzees within the GGE, as well as providing for the livelihood of people within the GGE area. Central to providing this livelihood is an emphasis on securing the water supplies. This assessment would also generate specific recommendations for actions to be taken in the short-, medium-, and long-term to restore the GGE. This report therefore includes recommendations for more focused assessments, and for long-term monitoring strategies. We place an emphasis on timeliness and practicality in the recommendations, with an intent to inform land use planning for the area.

Sponsors The request for this assessment was made by the U.S. Forest Service (FS) office of International Programs, in partnership with the U.S. Agency for International Development and the Jane Goodall Institute (JGI). Our contact at FS International Programs is Mike Chaveas, and with JGI, Pancras Ngalason and Emmanuel Mtiti. The Greater Gombe Ecosystem project is a JGI initiative.

Environmental Setting Gombe National Park, which falls within the GGE, became world famous with Jane Goodall’s work on chimpanzees during the 1960s. While the environmental setting of the Park has been well documented (Clutton-Brock and Gillet 1979, Bygott 1992, Pusey et al. 2007)), it is necessary to present a brief overview here to provide context for the observations and recommendations that follow. Gombe National Park was gazetted as a forest reserve in 1943, and elevated to national park status in 1968. The park is small, comprising a strip on the shore of Lake Tanganyika about 12 km long and 2.5 km wide. Vegetation includes evergreen woodland, deciduous dry forest, miombo woodland, and grassland. The park is steeply mountainous and highly dissected. The park provides sufficient area for three chimpanzee communities, designated, from north to south, Mitumba, Kasekela, and Kalande. In the 1980s, deforestation and conversion to agriculture of lands outside the park became increasingly evident. In part because of these pressures, the northern and southern communities (Mitumba and Kasekela) are vulnerable to population declines, and only the Kasekela community is relatively secure.

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As concern for the loss of habitat grew, it became evident that any ecosystem restoration efforts outside the park would need to involve the local populace and provide for their well-being. Accordingly, the Jane Goodall Instituted the TACARE effort, and more recently the GGE project. Some of the key elements of these initiatives are community involvement, reforestation aimed at restoring soil resources (with an agroforestry emphasis), improved water facilities for villages, AIDS awareness, and fostering ecotourism.

Figure 1. Context of Gombe National Park within the Greater Gombe Ecosystem (GGE). The

latter stretches north from the Park to the Burundi border. Reprinted from Pusey et al. (2007).

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Environmental Problems Deforestation outside the park has led to habitat loss for primates, soil erosion, increased landslides and flooding, in addition to a loss of biodiversity. Dry season water flows have likely decreased due to reduced groundwater recharge during the rainy season. Decreased

vegetation on steep headwater streams has led to debris flows and increased stream channel erosion, threatening village infrastructure. Current land use has lowered crop yields, and resulted in more scarce pole, timber, and fuelwood resources. From our observations it is clear that people are having an impact on the landscapes water and forest resources. Deforestation concerns vary with the forest type, as described in the following Observations section.

Figure 1. Deforested watershed in GGE area.

Observations

Watershed Conditions Geology / Soils The rift divide runs north south through the length of the GGE area. Streams and rivers on the west side flow into Lake Tanganyika, while rivers on the other side flow to the east and south towards the Malagarasi River which flows into the lake south of Kigoma. The area is characterized by steep slopes and narrow ridges. Most areas have slopes over 45%, with many steeper slopes. Ridge tops and many of the steep slopes have rock outcrops at the surface and appear to have thin soils, while other areas have deeper soils extending up towards the ridges The underlying rocks are gneises, with quartzite found on the upper slopes (Bygott, 1992). The highly weathered quartzite can be seen in outcrops on the ridge tops and upper slopes. Red sandstone can be seen on the bluffs above the lake. The rock appears to decompose primarily to sand on the western side of the rift divide, soils are most likely a sandy loam in this area. On the eastern side of the GGE area, the soils appear to have a mixture of fine sand and silt with a small clay component. Field soil texture analysis in one area indicated that those soils were a silt loam. Little soil information was found concerning the type and the variability of soils.

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Upland Watershed Conditions and Land Use Throughout the GGE area, with a few exceptions, most watersheds have been cleared of vegetation over approximately 90% of the watershed. Forests have been cleared through firewood cutting, burning and finally cultivation. Ridgetops are maintained as grassland vegetation through frequent burning. The upper slopes are currently used primarily for cultivation of cassava, with pineapple and cassava both being grown on the mid- and lower slopes. Banana and oil palm are planted in drainages, even extending high up the slopes in steep headwater drainages with sufficient moisture. The valley bottoms and riparian areas are used for cultivation of a variety of vegetables, including tomatoes and local greens, in addition to oil palm. A few farmers are diverting water from stream to irrigate these crops, although irrigated agriculture does not seem to be a common practice.

Figure 2. Crops on steep hillside.

Cultivation technique varies, with some areas contour cropping and some farmers using vetiver grass (Grimshaw, no date) to improve slope stability. In other areas the cassava and pineapple and planted up and down the slope, rather than along the contour. Two watersheds, which have experienced devastating flash floods in the past (discussed below) have allowed the forest in the upper watershed to grow back.

Figure 3. Burned area in Miombo Forest.

Within Gombe Stream NP, the watersheds are almost entirely forested, except for some of the high ridges, which have been burned repeatedly, for fire breaks and from fires creeping in from outside the park. Landslide (Mass Failure) Susceptibility Numerous recent small and large landslides were observed in the area, particularly west of the divide. The landslides all occurred on steep slopes (over 45%) where forest vegetation had been cleared, and were associated both with recent burning and/or with cultivation. A

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landslide did occur within Gombe Stream N.P. in 2005 in the headwaters of the Kakombe drainage. This landslide occurred after much of the upper watershed burned several months earlier. Observations indicate that the western side of the divide appears to be more prone to landslides, although several small landslides were observed on the east side of the divide. The smooth hillslopes found in the area do not indicate a long history of natural landslides, indicating that landslide frequency may be increasing. A more detailed assessment of geology and soils is needed to determine the landslide prone areas. Figure 4. Landslide in steep headwater stream.

Erosion Hazard Surface erosion was observed on steep slopes under cultivation. In areas of thin soils, cultivation and the resulting loss of soil may reduce long term soil productivity. Gully formation was observed primarily related to roads and trails, and in a few additional areas, however this does not appear to be a major concern, likely due to the high sand content of the soil, which decreases gully formation. Surface erosion, as would be expected, was most prevalent on sloping areas with little ground cover, such as crop land or areas recently burned.

River and Riparian Conditions The larger river valleys have well developed broad floodplains. Other drainages are V-shaped with steep side slopes, having only a broad riparian area at the mouth of the drainage. There is little native riparian vegetation remaining in the GGE area, with most riparian areas planted with oil palm and/or used for cultivation. Fragmites and a several other native riparian species were observed.

Figure 5. Oil Palms in riparian area.

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In Gombe Stream N.P., dense evergreen forest with large trees, vines and a dense understory was observed along the streams. Stream channels have many large trees along the banks, and both fallen trees and live trees across the stream channels, providing large woody debris to slow down water and create pools. All of the streams observed along the western side of the divide have high bedload movement, with large rocks in the stream bed (large cobble to small boulder size) that appear to move with each high flow. Debris flows1 and flooding have occurred recently in two towns, Mtanga in 2001 and in the Mwamgongo Village more recently. Both villages are highly deforested watersheds. In Mtanga Village, headwater tributaries in the northern portion of the upper watershed were scoured and downcut during an intense rainstorm, due to lack of forest vegetation, resulting in a large debris flow which traveled down the watershed and buried buildings in the village, including a refugee reception center, killing several people. In Mwamgongo Village, the river has a large sediment load from stream channel erosion in the headwaters, probably originating from intense rainstorms in the deforested upper watershed. The stream channel has downcut and is now widening to form a new floodplain. This stream channel erosion is threatening several buildings including the school, dispesery and mosque. Suggestions for stabilizing eroding stream banks is in Appendix 1. Bank erosion, widening and movement of the stream channel is common on streams on the western side of the divide outside of Gombe, where the stream flatten out as they approach the lake. The erosion appears to be increasing in recent years as the stream channels are widening. This is likely from the high runoff and subsequent high volumes of rock and sediment carried from the upper watershed to the mouth of the watershed, where the villages are located. The sediment is arising from landslides and from upper tributary streams downcutting during storm events due to loss of riparian trees. This erosion is threatening buildings in Zashe and Mwamgongo located along the lake north of Gombe. A recent study compared the Mwamgongo Watershed just north of Gombe with the Mitumba Watershed located within Gombe in the northern portion of the park. This study found that groundwater accounts for the majority of streamflow for these watersheds. The disturbed watershed discharged less groundwater and had an order of magnitude greater sediment load (Nkotagu, 2005). The streams within Gombe Stream N.P. also exhibit high bedload movement, however they are much narrower than the streams outside the park (5-10 meters wide as compared to 30-50 meters wide outside Gombe Park). This could be due to the intact riverine forest, in addition to having a forested upland watershed. In Gombe Stream N.P., there was a debris flow in 2005 on the Kakombe River. This occurred when a landslide in the upper watershed dammed up the stream, which then failed during a large storm, sending much rock and mud down the valley. The landslide occurred after the upper watershed had been previously burned when much of the park burned in 2004. On the eastern slope of the divide, the streams tend to have less bank erosion and appear to have more stable stream channels and banks. Flooding, debris flows and bank erosion concerns were not noted on this side of the divide. This could be due to several factors include geology, soils and/or precipitation patterns.

1 Debris flows are a mixture of soil, water and rock which flow as a liquid matrix down the valley.

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Water Sources Springs and seeps are common in the area. Most arise from hollows with moist vegetation, where a bamboo pipe has been placed in the hillside. The volume of flow varied, but some springs have significant flow in late August, which is towards the end of the dry season. In one drainage, many springs were observed, emerging from approximately the same hillslope position, indicating a change in geology. It is not known how many other areas have similar concentrations of springs. Most of the villages use headwater springs for water sources, which have been developed and piped to the village, with the aid of JGI and other agencies. As noted earlier, some drainages appeared to have more plentiful springs, likely due to geologic formations. Concern over declining spring and river flows were noted for most drainages. Declining water quantity could be due to both climatic and land use factors. Climate records were unavailable, so it is difficult to know at this time how rainfall patterns may have changed over the past decades. Land use, specifically repeated burning and cultivation on the steep headwater slopes, could exacerbate the problem through reduced infiltration on the hillsides, and lower water storage capacity of the riparian soils. This would result in higher runoff response during storm events, and lower base flows during the dry season due to less groundwater recharge during the rainy season. Dry season flows are also being reduced by oil palms and bananas planted along the streamcourses, which take up large amounts of water for evapotranspiration.

Reforestation In order to understand reforestation issues, it is first necessary to describe the forest types of Gombe National Park, areas outside the park influencing the park ecosystem (i.e., the GGE), and how these related to wildlife habitat and human livelihoods. By understanding the ecosystems of the Park, we have a benchmark to measure progress in providing habitat in other areas of the GGE. Within the Park we also have functioning soil, hydrology, and vegetation systems that provide guidance for providing human needs for water, soil, and agricultural resources.

Gombe National Park Gombe National Park (also known as Gombe Stream National Park) is a narrow (2.5 km wide and 12 km long) strip of mountainous terrain along the eastern shore of Lake Tanganyika (Fig. 1). The Park is 16 km north of Kigoma and accessible only by boat or by foot (Bygott 1992). At 4 degrees 40 minutes south latitude, temperatures are warm year-round, with relatively little fluctuation (between 19 and 28 degrees C year-round). In contrast, while rainfall averages 1600 m per year, it has varied widely, from this 1600 mm average in 1973-75, to about 2500 mm in 1976-1982, to 1500 mm in 1983-1988 (McGrew et al. 1996). The park is dissected by 13 high-energy streams running east to west. Altitude varies from 773 m at the lake shore about 1500 m at the crest of the ridge on the eastern park boundary (Bygott 1992).

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Vegetation Zones Gombe is characterized by five vegetation types: savanna woodland, evergreen forest, semi-deciduous forest, miombo, and the ridgeline ecosystem. The evergreen forest is distinct in following the stream corridors at low elevation, but the other types, while corresponding to soils and slope patterns, can grade into each other depending on disturbance history. Savanna Woodland This drier type is found on lower slope positions closer to the lake and is particularly abundant in the south end of the Park. Structurally, trees are spaced apart with an understory of tall (1 m plus) Hyparrhenia grass. Because of fire exclusion practices, however, some of

these areas are filling in with a shrub/tree understory. Common tree species include Annona senegalensis, a relative of the cultivated custard-apple, Diplorynchus condylocarpon, Terminalia and Combretum species, Strychnos, and Hymenocardia acidula. Many of these trees provide fruits or seeds used by chimpanzees, baboons, or monkeys (Bygott 1992). Diplorynchus and Combretum were among the five most common tree species in the park in 1979 (Clutton-Brock and Gillet).

Figure 6. Savanna Woodland Forest

Evergreen Forest

Evergreen forest follows the lower elevations of stream corridors in the park, is the most productive ecosystem (in biomass), and is the key habitat for chimpanzees (Collins, pers. comm.) Trees can exceed 20 m in height and include Anthocleista, Elaeis, Myrianthus, Pseudospondias, and Pycnanthus). Scattered oil palm and a few mango trees also remain, from previous settlement. Anthocleista has been documented as the second most common tree in the park (Clutton-Brock and Gillet 1979).

Figure 7. Evergreen forest in Gombe Stream N.P.

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Semi-deciduous Forest The semi-deciduous forest type (Clutton-Brock and Gillet 1979) is referred to as dry forest by Bygott 1992, and as mid-elevation forest by Collins (pers. comm.) It follows a band above the evergreen (riverine) forest in elevation, but also higher on the slopes within the narrow

river valleys. Fire exclusion has also led to this type encroaching on savanna woodland and miombo types. Common species include Parinari curatellifolia, Pterocarpus angolensis, Anisophyllea boehmii, Commiphora madagascariensis, and Antidesma venosum. Smilax is a common understory vine. In their 1979 transect survey, Clutton-Brock and Gillet found Anisophyllea to be the most common tree in the park, and Pterocarpus within the top five most common.

Figure 8. Remmant patch of semi-deciduous forest.

Miombo Miombo forest is characteristic of the GGE and is well-represented within the park, particularly at higher elevations above semi-deciduous forest. Classic miombo features Brachystegia spp., and this is present at Gombe, but Clutton-Brock and Gillet (1979) also describe a Uapaca miombo type within the park. Fire exclusion may mean this type is decreasing somewhat (converting to semi-deciduous forest), but it is still well-represented.

Figure 9. Miombo forest in Gombe Stream N.P.

Ridgeline The highest reaches of the park feature protea and giant heather interspersed among rock outcrops. Most of this area, however, has enough soil to support a rift grassland Bygott (1992). This type is maintained by yearly burning by park staff, with the objective of this serving as a firebreak to protect lower elevations of the park. If this burning were removed, these areas would probably convert to miombo woodland. We found evidence of trees growing back in some of the burned area, and even semi-deciduous forest in a protected area.

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Figure 10. Ridgeline vegetation type.

Disturbance History Two key factors emerge when considering changes in the Park over time: 1) Because the park area included human settlement until 1943, this had an influence on forest age and composition; and 2) fire (and its exclusion) have a significant role in shaping the park vegetation. Until 1943, settlements undoubtedly were using the area for agriculture, as

evidenced by the oil palms still remaining in some of the valleys. Presumably people were also using the forest for timber and firewood. Fires at this time were started low (Clutton-Brock and Gillet 1979), in the savanna woodland. In contrast, today’s fires are nearly all in the upper slope areas, prescribed by park staff to serve as a firebreak protecting the rest of the park. Since the park has been influenced by settlement and fire, Clutton-Brock and Gillet in 1979 concluded “little of the forest is climax.” Vegetation types described here are therefore existing, and not potential, vegetation. Of the types described, evergreen (riverine) vegetation appears the most static, while savanna woodland, semi-deciduous forest, and miombo woodland form a shifting mosaic depending on fire frequency and severity. It is important to remember this when using the park as a benchmark to compare with surrounding areas, since the park does not necessarily represent the tallest trees or optimal mix of seral stages for the greater ecosystem. In 2004 prescribed burning was delayed; when finally implemented in August 2004 it escaped and fire burned about 60 percent of the park area. Photographs supplied by Anthony Collins (pers. comm.) suggest the fire was low to moderate in severity. The fire may have influenced the development of a January 2005 debris flow in the Kakombe Valley, which destroyed a bridge and part of the park staff housing, but fortunately resulted in no loss of life. Despite the debris flow, there does not appear to be adverse long-term effects from the fire.

Management Implications From the literature, discussions with JGI staff, and our own observations we conclude the Gombe park ecosystem is functioning well. The shifting mosaic of its forest types (other than evergreen) serves to provide a variety of fruit and seed resources for chimpanzee use, critical since they feed approximately 6 hrs per day year-round (Bygott 1992, Collins pers. comm.) The main concern for Gombe is not within the park, but in its relation to the larger landscape (i.e., the GGE). The conversion of the majority of the surrounding area to agriculture means the park is effectively isolated. Chimpanzees and other wildlife venturing outside the park are likely to be killed eventually because of conflict with agriculture or by hunting. In any case they would not find the variety of food resources characteristic of the park, nor the tree structural diversity they use for resting and avoiding predators.

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Genetic variation within the three chimpanzee communities appears adequate for the population to persist for some time, as predictions indicate the populations would lose only about 5 percent of this variation over the next 100 years (Collins pers. comm.) The greater threat appears to be a risk of disease decimating the populations, as they have experienced outbreaks in the past. The chimpanzee population in the park appears to have declined from about 150 to 100 individuals since about 1970 (Pusey et al. 2007). Chimpanzee populations do not expand rapidly, as do those of baboons (Collins pers comm.). Suitable, safe habitat outside the park would have to be available for some time before a new community of chimpanzees could expand there.

Deforestation in the Greater Gombe Ecosystem Our field trips of Aug 21-24 and Aug 26, 2007 made it clear that areas adjacent to Gombe park have experienced significant deforestation in recent years. Even casual observation, either by satellite imagery or on the ground, shows a sharp contrast between the park and adjacent areas. Outside the park, native trees exist primarily as small remnant patches or even as individual trees. The implications of this for water resources are discussed in the Water section. Following are the effects of deforestation on forest and wildlife habitat resources. Wildlife habitat Chimpanzees require a mix of habitats for a variety of food resources, with evergreen forest in riverine valleys the key component (Collins pers. comm., Pusey et al. 2007). Outside the park, this variety has been lost. Riverine areas are favored for village sites and oil palm plantations. In upland areas, we observed even the steepest areas being used for agriculture (primarily cassava, with burning to maintain goat grazing in some areas). Regardless of food sources, however, there appears to be an irreconcilable conflict between chimpanzees (and baboons and monkeys, for that matter) and people. These primates are seen as adversely affecting farms (by eating crops), as a source of meat, and even as threatening human children. If primate populations are to expand, therefore, there must therefore be a zone of reduced human use to meet there needs. This will be discussed further in the recommendations. Forest structural and species diversity Clearly, structural diversity has been lost outside the park. Gone are the levels of tree canopy diversity that provide shade and help maintain soil. This in turn has led to a loss of shade-tolerant tree species. Frequent burning and planting of crops means that most other native tree species have been decimated as well. Loss of timber, fuelwood and poles Intense agricultural pressure on the land through a rapidly expanding human population has meant a loss in timber, fuelwood, and pole resources. Villagers must often make long treks to obtain these resources, and we observed trees being cut down in remote areas. Nearly all the larger trees are gone from the landscape.

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Losses in soil productivity On upland slopes, frequent burning and planting of crops has probably depleted soil nutrients and moisture. In cases where this has triggered significant erosion or landslides, particularly in the western half of the area. It will take a long time for these soil resources to recover. Fortunately, it appears many of these areas would recover rapidly if cultivation ceased, as we witnessed at Zashe village (north of the Park). One hillside had been free of cultivation for 12 years and was consistently covered with naturally-regenerated trees about 2-3 m in height. Human implications Unless agricultural practices change, intense pressure on the land means that the area has probably been saturated in the amount of people it can support. With the status quo, this means declining crop yields, longer treks to gather fuelwood, and declining water quality and availability.

Figure 11. Children in a GGE village.

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Summary and Conclusions: Current State of the Greater Gombe Ecosystem The almost total deforestation of the watersheds has led to an increase in landslide and debris flow frequency and increased the severity of flooding. Deforestation has also decreased flows during the dry season due to reduced infiltration across the watershed, and subsequent groundwater recharge. Stream channels are much wider outside the Park than within the park, due to increased bedload movement and stream channel erosion resulting from higher high flows during the rainy season and the loss of stabilizing riparian vegetation. If land use practices are not altered, over time the soil productivity on the hillslopes will likely decrease to a point where it will be difficult to have natural regeneration of forest. Stream channels will continue to be unstable and widen, which will impact village buildings and infrastructure. We conclude a similar severe impact on the GGE’s forest resources outside the Park. Most native forest is gone or reduced to small patches or individual trees. In the areas we observed, evergreen (riparian) forest is essentially gone as an ecosystem, replaced by oil palm and banana plantations, and by village sites. Timber, pole, and fuelwood resources are scarce. The ameliorating effects of trees in providing shade, conserving soil and water, and providing wildlife habitat, are largely absent. For example, we saw no primate wildlife outside the Park, and noticed a lack of bird life. The net effect of these impacts are an isolated and vulnerable Park for wildlife, and a human environment outside the park stressed and degraded in its ability to provide for human needs of water, wood, and agriculture.

Current Restoration Efforts in the Greater Gombe Ecosystem Watershed Restoration Efforts JGI has been working in the area, establishing pilot programs, tree nurseries and improving

water sources. The agroforestry projects, including contour cultivation and terracing with vetiver, in addition to using mulch to retain water and protect soil appear to be very effective in increasing infiltration and improving soil stability. In suitable areas, coffee is being grown interplanted with banana, using mulch to protect the soil. This system appears to be quite effective in maintaining soil productivity and increasing agricultural production.

Figure 12. Coffee interplanted witth banana.

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Water projects include developing and protecting springs and piping the water to villages. Roof rainwater harvesting systems have been installed as a pilot project for a few areas with limited access to water. Included in these projects are restrictions on land use around the water source for projection. These projects appear to be well designed and effective to secure long term water supplies. Water quantity will always be a concern, particularly if the population continues to grow at the current rate (currently 4.8 percent per year).

Figure 13. Spring box water source protection.

Tree nurseries JGI, through the TACARE (Tanganyika Catchment Reforestation and Education Project) initiative, has established tree nurseries at each of the key villages in the Greater Gombe

Ecosystem. A community contact person (forest monitor) is also associated with each of the villages to run the nursery and foster agroforestry. A variety of tree species, both native and non-native, are being assessed. Production in nurseries has included the following species: Maesopsis eminii (muhula), Eucalyptus madenii, E. serigina, E. citriodora, E. grandis, Caliandra (motonyaka), Grevillea robusta, and Pinus patula. A complete list of tree species produced and used for reforestation in the GGE is found in Appendix 2.

Figure 14. Tree plantation.

Nurseries are also producing vetiver grass, used in contour soil erosion contol, but are having trouble keeping up with demand, as it takes 2-3 years for the grass to grow to a size suitable for use. Although not produced at nurseries, JGI also obtains hybrid oil palm seed, producing greater yields, for distribution to villagers. We saw a number of community nurseries, a number of areas planted with trees, and met with village leaders. JGI staff appear to be doing a good job of producing tree seedlings and establishing them in plantings, with the cooperation and support of the villages. Our observation is that they are doing all the right things, but the work needs to be accelerated many times over and more resources put into it.

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Recommendations We have organized our recommendations into three levels. The first level comprises an Action Plan with immediate steps to be taken on the ground. Level 2 is a recommendation for targeted surveys that should be completed within 2-4 years. The third level recommends long-term ongoing studies to implement without a completion date.

Level 1: Action Plan: Immediate steps to take on the ground We commend the JGI staff for their work in establishing tree nurseries, agroforestry, tree plantings, and outreach to the villages. Our only comment is that the work needs to be accelerated and expanded quickly. Timeliness is critical. Zone Concept We suggest a zone concept be adopted, with different areas zoned for different intensities of management. The mix of zones within a planning area (we suggest village boundaries) should be negotiated with each village council. Villages giving up the most for the sake of habitat and water conservation should, in fairness, receive the most compensation in terms of water sources, agroforestry extension services, improved seed, and community facilities (such as clinics). The following serves as a possible outline for the zones:

Zone 1. Natural regeneration zone.--Slopes above 45%. (These areas would typically be in miombo or semi-deciduous woodland if not affected by agriculture.) Suppress fires until trees free to grow. No wood gathering. After 10 years review this to see if partial cut is appropriate. After trees are free to grow, allow no more than 20 percent of the zone to burn per year. (This is strictly a working hypothesis.) Use the fire history study from Level 2 (see below) to refine the optimal amount of fire to tolerate per year. Bee-keeping encouraged in this zone. Regenerating these steep slopes is especially important for the watersheds draining to the lake due to the higher landslide hazard. Zone 2. Natural regeneration zone – Evergreen (riverine) Forest: This should be encouraged for several of the valley bottoms farthest from villages and could potentially overlap with the water source protection areas described below. These conservation zones would allow natural regeneration of evergreen forest. Land use planning may call for some of these areas to have small settlements to be abandoned to regenerate naturally. These decisions should be made with the full involvement of the villages, be on a willing basis, and involve incentives/compensation for the abandonment. These areas should be monitored every five years to determine if the correct mix of tree species for chimpanzee food and habitat is regenerating, and to determine if interplanting with native species is necessary.

Zone 3. Tree plantation zone. Trees are planted in a mix of native and non-native species to meet timber, pole, and fuelwood needs. The proportions of native and non-native species in the mix should be negotiated with the villages and farmers involved. Fire is excluded.

Zone 4. Agroforestry zone. Interplanted crops and trees using sustainable, improved agricultural practices, such as contour planting with vetiver grass, shade coffee, and use

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of improved oil palm seed. Carefully chosen deciduous tree species can conserve water during the dry season compared to evergreen trees (Rumley and Ong, no date, Rumley at al. no date.) Integrated food crop and tree systems can greatly increase rain utilization, although a careful consideration of trade-offs in crop yields versus wood output must be considered (Lott et al. 2003). Fires are excluded.

General Guidelines for All Zones 1. An emphasis on building on existing forest patches for natural forest expansion

wherever possible.

2. Agriculture and housing should be excluded within 200 m of water sources

3. Develop appropriate fire suppression resources, including construction of firebreaks, trained fire suppression/management crews, and regulated prescribed burning time periods. (For example, burning at the end of the rainy season might be most appropriate.)

4. Incentives of improved water sources, access to hybrid seeds, extension services, and community facilities (such as fish drying sheds and clinics) should be emphasized when the objective is to improve land use practices. Decisions should continue to be made with the full involvement of the villages. Any land abandonment, which will probably be necessary in some of Zone 4 (riparian zones) should be only on a willing basis, agreed on by negotiation.

5. Water source protection practices: For water intakes on streams, encourage natural regeneration of forests for a minimum of 100 meters on either side of the stream around and upstream of the water pipeline intake. Research has shown that a 100 meter wide buffer of forest will greatly reduce bacteria and sediment transport to streams. For springs used as water intake, encourage natural regeneration of forest for a 100 meter buffer around the spring box, including any moist soil areas adjacent and upslope of the spring. Springs used as community water supplies should be tested regularly for bacteria and other contaminants, as specified by local regulations,

6. Once land use decisions are made, they should be regulated by the villages themselves.

7. Appropriate ecotourism opportunities should be pursued to provide local employment and an incentive for Park conservation.

8. Any land use planning should incorporate realistic human population growth projections, and not be based on the current population level.

9. During our field review there was discussion of an option of encouraging people to move to an area south of Kigoma. Any relocations considered should be on a willing basis, with incentives and/or compensation for moving. We further stress that this southern area also receive an assessment of its capability of absorbing human population, as we understand it also has wildlands and a chimpanzee population.

Level 2: Short Term (within 2 to 4 yrs) Focused Assessments 1. Water source inventory. Complete a water source inventory of springs, and streams,

which are, or could be, used as community water supplies. The inventory should occur during the middle to late dry season and include at a minimum, the following

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data items: GPS location, elevation, spring type, spring flow rate, geologic setting, land use setting, current water uses. Data could be stored in an Excel or Access database with a link to the GIS spatial information. This forms the baseline for the long term water source monitoring described under level 3 below.

2. Fire history study on semi-deciduous, miombo, and savanna woodland types. This would largely be a literature review based on these forest types elsewhere in Tanzania, or eastern and southern Africa. Tree ring studies are often not practical in the tropics because of indeterminate growing seasons.

3. Soil survey focused on soil productivity, mass wasting and surface erosion hazard, as well as relating soils to forest types. One year duration. We suggest a United Nations (UNDP/FAO) expert with a Tanzanian student counterpart. Satellite imagery should be used to help stratify the field sampling. (JGI already has good GIS/remote sensing capability.)

4. Tree species trials to further build on the substantial progress made to date. Identify additional native species for all forest types, especially the evergreen riparian type. Such species trials would yield results within 2-3 yrs, but should be ongoing to verify findings.

5. Detailed assessment of stream channels and watersheds where stream or river is eroding and threatening village infrastructure. This would include Zashe, Ngoyna (Mwamgongo) and Mtange watersheds and any other applicable areas. This assessment could be completed in several weeks with the end product being potential restoration projects for key watershed areas to reduce river instability.

Level 3: Long-Term Ongoing Studies

1. Establish a Long Term Vegetation Monitoring/Watershed Conditions Network. This would accomplish three important objectives: 1. Quantification of the Gombe Park as a baseline for comparison; 2. Monitoring changes over time, and 3. Measuring how successful restoration efforts outside the Park are when compared with the Park baseline. Objective 3 is therefore a key measure of success in restoring the GGE.

This network would include a set of GPSed grid points on the ground tied to satellite imagery. The study can be designed both to classify vegetation types more precisely than at present, and to provide data on biomass changes over time. Suggested categories for the mapping include: grassland, miombo forest, evergreen forest, savanna woodland, semi-deciduous forest, cultivated land, landslides and fire scars. The categories should remain as consistent as possible from year to year. The grid points provide ground verification and also identify changes over time. Products include a map and a table with hectares of land within each category by watershed and by village area. Also generated would be a more concise classification of the composition and structure of the vegetation types.

Sampling proceeds on a set number of plots each year (typically 20-25% of the total sample) so that the sampling target per year is not overly burdensome. Annual satellite imagery would be useful for monitoring landscape changes. We will check with the US Forest Service remote sensing center to see if this is

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feasible. Annual satellite imagery would provide an annual report on changes, with more precise reports every 5 years or so as the ground data are updated. We stress that annual measurements, although not a complete dataset, should still be adequate to monitor changes on the landscape sufficient to compare Gombe Park with adjacent areas. Ground data points for this effort should include basic tree shrub measurements, species identification, and ground photo points for monitoring. Points should be permanently marked for long-term sampling. The sampling effort would take about 2 weeks time for 10 personnel per year, including training. The main equipment needs are compasses, GPS units, and tree measuring clinometers and diameter tapes. If JGI has sufficient GPS units available (and they appear to), equipment cost for vegetation monitoring should not exceed US$500-1000.

This monitoring would also track changes in watershed conditions, and could be completed for the entire GGE and Gombe area or for selected watersheds. This would be a measure of effectiveness of the Level 1 actions in regenerating forests and reducing landslides. This information could also be used to model water conditions if desired.

2. Basic Climatic Monitoring: This monitoring would be used to help determine climate

related factors for forest regeneration speed and success. As Gombe is a site with long term ecological research, climate is basic data which would contribute to most types of research.

An inexpensive method would be install a raingauge and a maximum/ minimum thermometer, and assign someone (possibly a researcher) to daily record the values. Estimated equipment cost: $50 A more expensive option is to install a solar or car battery powered weather station, such as is available from Davis Instruments, Oregon Scientific, or other suppliers. These weather stations can be downloaded every several months with a laptop and so do not need daily attention. The weather station would need to be protected from vandalism (either human or primate). Estimated equipment cost: $1500

3. Water Source Monitoring: This monitoring would detect changes in groundwater

flow which will give the communities more information about their water source and alert them to potential water shortages. If combined with a rain gauge network, this information can be used to indicate trends in groundwater quantity and watershed condition.

Choose a subset of springs and measure flow rate either bi-weekly or monthly during the dry season. This can be accomplished using a bucket with measurements inscribed on the side and a watch or stopwatch. Forest monitors could complete this monitoring. This will establish trend in groundwater flow and with the rainfall gauges, could be used to determine changes in groundwater flow due to improved watershed condition. Estimate equipment cost per Forest Monitor: $25

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4. Rain gauge network. A network of rain gauges placed throughout the area would

provide information to determine if changes in water flows are related to watershed conditions or to precipitation patterns. The optimal network would include rain gauges at each village in addition to remote automatic rain gauges.

A network of rain gauges at villages could be established. The data could be recorded either by a school teacher or by forest monitors. Estimate equipment cost per village: $25 Remote automatic rain gauges ($700 USD) could be placed on ridgetops, if a secure location can be found. Four to six gauges would be necessary. These gauges can be downloaded quarterly into either an excel or access database. Estimated equipment cost: $2800 to $4200

5. Stream flow measurements. In addition to springs, streamflow in major streams could

be measured during the dry season. In combination with the raingauge network, this could indicate if changes in low flows are due to precipitation patterns or watershed condition.

The best way to accomplish this would be to use a stream velocity meter, and to measure the velocity and record stream channel dimensions. Equipment required is a tape, a wading rod and a velocity meter. Measurements would take approximately one hour per site. Estimated equipment cost: $1500

6. Photo points for stream channel. For streams and rivers of concern, establish a set of

repeatable photopoints to detect change in the stream channel. These could be repeated every 2 to 5 years to determine if the reforestation of the watershed is improving stream channel stability. Estimated equipment cost: None

Recommendations for Further Involvement of U.S. Forest Service International Programs The Forest Service could assist by facilitating implementation of the Level 2 and Level 3 assessments recommended above. In the Level 2 category (short term assessments) a Forest Service hydrologist could set up a water source inventory, as well as a detailed assessment of stream channels and watersheds. Additionally, the authors of this report could help in focusing the design of the recommended fire history and soil survey assessments so that they will achieve the stated objectives and be accomplished over a relatively short period of time. The long-term (Level 3) recommendation for a vegetation monitoring and watershed conditions network could be set up on a short assignment, providing an efficient field design is used. Likewise, basic climatic and water source monitoring, a rain gauge network, stream flow measurements, and a photo-monitoring scheme (both for vegetation and stream channels), could be established in a relatively short time. The Forest Service has worked in Kenya on improved fire suppression and management and could also contribute expertise to teach the villages appropriate techniques to improve fire management in this area.

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Of course, the success of any of these monitoring frameworks depends on the involvement of the Jane Goodall Institute. We recommend a Tanzanian graduate student or students be recruited to work on implementing and continuing these monitoring efforts, with the goal of their eventual employment with JGI. In some cases, such as species trials development, a US Peace Corps volunteer located in Kigoma or a village in the GGE, would be a good investment. We (the authors) would be glad to assist with implementing these efforts. In the event others are selected for technical assistance, or are added to our effort, we advise they be fully briefed on methods. For example, one author (DeMeo) has in concert with colleagues developed an effective vegetative monitoring system for situations such as the GGE. The method combines GPSed ground data with satellite imagery for effective landscape monitoring over time.

Summary of Recommendations: Measures of Success 1. Greater area each year in the GGE (outside the Park) in tree plantations and

sustainable agriculture.

2. Increase in area with natural regeneration outside of the park, in accordance with agreed upon land use planning.

3. Area outside park begins to approximate mix of vegetation types and biomass within the Park.

4. Stream channels and water flows outside the Park approximate those within the Park.

5. Landslide occurrence decreases.

6. Basic climatic data available for GGE.

7. Frequency and severity of fires in non-evergreen types approximates our best understanding of the historical fire regime.

8. Chimpanzee populations become more secure and expand.

9. Human standard of living increases, as measured by access to water, schools, clinics, and income.

The Way Forward In a managerial context, our observation is that the JGI team, through the TACARE and GGE efforts, is doing all the right things: working closely with the villages, establishing nurseries and tree plantings, putting forest monitors in place, promoting shade-grown, sustainable coffee to improve local incomes and to raise funds for ecosystem restoration, and encouraging more sustainable agriculture. Early during the visit we realized that their efforts were worthy of support and should be expanded. Our recommendations in a program management context are therefore as follows:

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1. Timeliness is critical for success. The areas adjacent to Gombe Park are severely altered; habitat will need to be restored quickly if chimpanzees and other wildlife are to remain viable. If the watersheds are not restored, they could become so degraded as to no longer support forests, at least in some areas.

2. With this in mind, we recommend actions and assessments be completed in as rapid and as practical a manner as possible. We believe this report shows this.

3. Successful project management requires a sustained commitment to see things through. We believe Mr. Mtiti and his staff have demonstrated this commitment.

4. Given the importance of a world-famous chimpanzee population, the clear human needs in the area, and demonstrated success by the JGI team, we believe the JGI Greater Gombe Ecosystem effort is worthy of substantial investment by donors. JGI is a good investment.

5. The funding needed to provide the assessments is relatively modest and within the realm of US AID support. The larger funding question is how JGI can support incentives for villagers to pursue more sustainable agriculture, and move out of certain areas adjacent to the Park. This may require compensation, a cost that could become substantial.

Acknowledgements We gratefully acknowledge the assistance of Mike Chaveas, USDA Forest Service International Programs, for recruiting us to this effort. Lilian Pintea of JGI staff in the US gave us a valuable briefing and provided excellent GIS coverages of the assessment area. Pancras Ngalason and Emmanuel Mtiti of JGI worked hard on our logistics of arriving in Kigoma. Once in Kigoma, Emmanuel and JGI staff provided us with a superb overview of the GGE, both inside and outside Gombe Park. We offer sincere gratitude to all the following:

Philip Francis, water Jovin Rwehabura, GIS database analyst Frank Kaduma, monitoring and evaluation officer Aristides Kashula, Head of Forest Section, Asst. Project Manager Adamu Kohoye, forest monitor, Bubango village Julius Ishabakaki, water Rob Sassor, conservation action plan Dr. Anthony Collins, Gombe Research Station Mary Mavanza, - TACARE Project Manager Amani Kingu, - Agroforestry Boniventula Luzilo, - Forest Monitor Kalinzi Village Peles Magiri, Head Community Develop Section

Literature Cited In addition to the following documents, we strongly recommend the World Agroforestry Centre’s website (www.worldagroforestrycentr.org) as an exceptional source of information. The website includes synthesis papers on relevant topics, and an online library search feature;

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e.g., a search on “miombo” returned 97 entries. This website would be a good resource for researching the silvicultural characteristics of native vs. non-native tree species. For information on vetiver grass, see www.vetiver.com

Bygott, D. 1992. Gombe Stream National Park. Kigoma, Tanzania: Tanzania National parks/African Wildlife Foundation, 71 pp.

Clutton-Brock, T. H., and J. B. Gillett. 1979. A survey of the forest composition in the Gombe National Park, Tanzania. African Journal of Ecology 17:131–158.

Collins, A. pers. comm. Kigoma, Tanzania: Jane Goodall Institute, August 2007.

Grimshaw, R. no date. An introduction to vetiver grass technology. On the web at www.vetiver.com/kuw_workshop_papers/kuw_1dg%20.pdf

Lott, J.E., A.A.H. Khan, C.R. Black, and C.R. Ong. 2003. Water use in a Grevillea robusta-maize overstorey agroforestry system in semi-arid Kenya. For. Ecol. and Manage. 180:45-59.

McGrew et al. 1996. Great ape societies. Cambridge Univ. Press

Nkotagu, H.H. 2005. Paleolimnological investigations of anthropogenic change in Lake Tanganyika: VIII. Hydrological evaluation of two contrasting watersheds of the Lake Tanganyika catchment. J. of Paleolimology 34: 107-123.

Pusey, A.E., L. Pintea, M.L. Wilson, S. Kamenya, and J. Goodall. 2007. The Contribution of Long-Term Research at Gombe National Park to Chimpanzee Conservation. Cons. Biol. 21(3):623-634.

Rumley, R., C. Muthuri, and C. Ong. No date. More trees with less water. Available on line at www.worldforestrycenter.org/water, 4 pp.

Rumley, R. and C. Ong. No date. The right tree for a dry place. Available on line at www.worldforestrycenter.org/water, 4 pp.

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Appendix 1 Recommendations to Slow Bank Erosion for Zashe and

Mwangongo Villages For both of these villages, and any others which have erosion problems, a more detailed study of the stream channels in the watershed is recommended. This field work may discover areas in the upper watershed which could be stabilized to reduce the amount of bedload traveling down the river. Mwangongo Village Along the Ngonya River, the bank is eroding and threatening the school, dispensary and Mosque. The recommendation is to place rock along the base of the bank, up to about 2 meters if possible near the dispensery. Remove the large tree near the mosque as it is aggravating erosion near the Mosque. Zashe In Zashe, the river has changed course and now is eroding a large bank closer to the village, threatening buildings. The irrigation diversion dams may be contributing to changing the direction of river flow during high flows, so it is recommended to request that the irrigators knock down the diversion structures before the high flow season. To slow erosion of the bank, remove rock from the bar opposite the eroding bank. Place the rock along the base of the bank approximately 2 meters high and 2 meters out into the stream channel. Build lines of rock jutting out into the stream channel (barbs). The barbs should not extend more than 1/3 of the way across the stream channel. They should be about 1 ½ meters high at the bank, sloping down towards the bottom of the channel. They should point upstream with an angle of about 30 degrees from the bank. Large rocks should be used as it is the most stable. Barbs should be placed about every 15 to 20 meters.

Eroding bank

Approximate 30 degree angle from bank

Upstream pointing barbs

Rock Barb

1.5 m high

Slopes down to bottom of the stream channel

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Appendix 2 Tree Species used by the TACARE Project in the GGE (provided courtesy of Aristides Kashula, JGI staff)

Uses Status SPECIES

Fuel wood Timber Agro Watershed

Restoration Fruit Live hedge

Bee pollen Med

Soil Erosion Control

Cavings Shade Ind Exot

Khaya anthotheca (xx) x x x x x Spathodea campanulata (xx)

x x x x

Sapindus saponaria (xx) x x x Afzelia quanzensis x x Dalbergia mellanoxyllon x x Albizia chinensisia x x x Albizia lebbek x Acrocarpus fraxynifolius (*)

x x x x

Ficus natalensis (xx) x Delonix regia x x Grevillea robusta (*) Calliandra callothyrsus x x x x Acacia tortilis x x x x x Acacia nilotica x x x x Tamarindus indica x x x Tectona grandis x x x Leucaena diversifolia x Syzygium cumnii x x x Maesopsis eminii (xx) (*) x x x x Gmelina arborea x x Pterocarpus angolensis x x x

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(Pr) Azedratchta indica x x x x Melia azedratcta x x Mangifera indica x Milicia excelsa (xx) x x x Psidium guajava x x Cassuarina`equitisetifolia (*)

x x x x

Trichelia emetica (xx) x x x x Annona squamosa Pithellobium dulce x x x Cuppressus lusitanica (*) x x x Persea americana (Avocado)

x x x x

Schinus molle x x x Jacaranda mimosifolia x x x Acacia polycantha x x x Pinus patula (*) x x Senna siamea x x x x Warbargia salutaris x x x Artemisia annua x x Sterculia africana (xx) x x x Cedrella ordorata x x x Cedrella serrulata x x x Citrus lemon x x Citrus laurantifolia x x Artocarpus heterophylla x x Citrus reticulata x x Dates x x Cordia abbyssinica x x x Croton megallocarpus x x x

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Dovyalis caffra x x x Faidherbia albida x x x x Markhamia lutea x x Markhamia obustifolia x x x Moringa oleifera x x x Peltophorum pterocarpum x x Sclerocarya birrea x x x Zanthoxyllum challybium x x x Varieties of ornamental plants

x x

Terminalia mantaly Terminalia cattapa x x x x Terminalia superba (*) x x x Vanguela enfausta x x Syzgium cordatum x x x Newtonia buchanani (xx) x x x Erythrina abyssinica x x Acacia mearnsii x x Balanites aegyptica x x Bauhinia thoningii Azanza garkeana x x Parkinsonia aculeata x x Key: (xx) – Planted on the water catchments and proved to perform better, we intend to multiply these efforts. (*) – Planted on woodlots for timber and fuel wood on village settlements.