The majority of human activity takes place in the north of the catchment area. Land in this area is mainly used for keeping livestock such as goat, sheep and poultry and for agricultural purposes, a farm on Bonaire is called a ‘kunuku’. It is unclear up to what extend activities in the catchment area influence Lac Bay.
Wells and dams
Wells and dams are placed to supply water for the kunukus. This water is mainly used for agricultural purposes. With these structures the original water flow towards Lac Bay, is interrupted, which causes less fresh water to end up at the mangroves.
Figure 12. Well driven by a windmill (By author). Figure 13. Dam collecting water (By author). Figure 14 indicates activities in the catchment area which alter the superficial water. Herein it should be noted that more dams and wells are present in the area. Unfortunately it was not possible to reach all locations during data collection because the majority of the area is inaccessible and limited time was available. Black lines indicate dams which were present in 1984 according to the Kadaster map. Most of these dams are probably still present in the area in the same size. Some of the dams which were found were not present on the Kadaster map. This indicates that the number of dams has been increasing since then. The wells indicated are found next to the road and are available for public use. Some are driven by a windmill (figure 12). An unknown number of kunukus has wells present on their own land. Out of 17 questioned kunuku owners, 4 stated that they have a well on their own land. 8 respondents stated that they have dams on their parcel, ranging up to 4 dams per individual respondent.
Figure 14. Locations of water related activities (By author).
Livestock
The main activity at the kunukus is keeping livestock. This livestock mainly consists out of goats and some sheep. Donkeys can also be found in low numbers. These animals do not have owners and can be considered wild animals. Livestock is often let loose to roam free across the mundi (bush), during the day, allowing them to strip off a large part of the surrounding vegetation. This causes erosion and eventually lets water streams take the sediment to the bay. The livestock can also cause eutrophication through nutrient enrichment originating from livestock manure. (Slijkerman, 2011) As mentioned, the livestock on Bonaire mainly consists out of goats. An exact number of goats on Bonaire is difficult to determine but in recent research an estimation was given of 25.000 to 26.000 goats and around 5000 sheep (Nolet, et al., 2009).
Goats are very important to the native Bonaireans. These animals are capable of making use of the available vegetation under extreme circumstances (French, 1970). Therefore the breeding of these animals is not primarily dependent on the land they live on, but on the goats themselves. For many Bonaireans goats are an interesting investment. With enough rain the goats can have young twice a year, so that every year on 100 goats on average 100 young survive (it should be noted that in times
of drought fertility can decrease with 30%). Goats are seen as a sort of insurance. In difficult times some animals can be sold. An adult goat can on average be sold for about 50 USD. Goats have always been an important export product to Curaçao and Aruba (Nolet, et al., 2009).
According to Mr. Eemers, director of Dienst LVV (service for agriculture, livestock and fishery) it is officially forbidden to let goats loose. Currently however, this rule is not being followed like it used to be, and enforcement is barely occurring. According to many kunukus and Nolet et al. (2009) letting the goats out to roam free enables them to feed on the islands vegetation, rendering it unnecessary to feed them. This saves money and enables the owner to keep more goats. Number of goats and the carrying capacity
For Bonaire the LVV service at Curaçao has determined the total number of goats that the
environment can sustain without degradation. A carrying capacity of 14 goats per hectare in the rain season and only 1 goat per hectare in the dry season (In which 30.000 goats are assumed on 7.000 hectares of suitable ground for livestock) was determined. This means a carrying capacity of 7.000 goats in the dry season. Since this season endures for about 8 months of the year this would be a good guideline for the carrying capacity in general. This would mean that the total population would have to decrease to ¼ of the current number (Nolet et al., 2009).
Research in the Washington Slagbaai National Park by Debrot (2009) showed that 1 goat per hectare is present here. According to Debrot, this number still leads to degradation of the vegetation. A study in the Christoffel Park on Curaçao, shows that general vegetation and rare species are starting to improve at cattle densities of 1 on 10 hectares. These areas are comparable to the Lac Bay catchment area.
It can be assumed that in the Lac Bay catchment area these densities are being exceeded. In Lac Bay, the total amount of suitable land for livestock is unknown. The total area encompasses about 2260 hectares. Based on information from DOMEIN, a total number of at least 213 kunuku’s in this area can be found, of which many are holding livestock, either roaming free or on the parcel. A total of around 300 kunuku’s is estimated for the entire catchment area. 17 kunuku owners were asked about their number of livestock and hectares they own. Unfortunately this sample is too low to give an indication of the number of goats per hectare in the catchment area, and thus more need to be asked. Numbers per respondent ranged between 0 and 80 goats and 0 to 30 sheep. On parcels of which the surface in hectares and its owner was unknown, high numbers were counted as well, sometimes ranging over a hundred goats and sheep. Anecdotal stories indicate that one of the largest kunuku’s in the catchment area, Kunuku Warahama, contains hundreds of goats, sheep and other cattle.
Although an indication of the actual density of livestock in the catchment area cannot be given, the number of grazers is probably much higher than the mentioned values for the carrying capacity, based on literature, anecdotal stories, observations and the questionnaire.
Livestock back on the parcels
As mentioned earlier, legally it is not allowed to let livestock roam free. The first step in restoring Lac (especially the mangrove area) is to stabilize shorelines by reducing sediment transport into the system. Enforcing this law, requiring kunukus to keep their livestock within the fenced boundaries of their properties , in combination with decreasing vehicular traffic in off-road areas could reduce the sedimentary problems (Slijkerman et al. 2011). According to Mr Eemers (director of LVV), the LVV service is working towards this. In this matter some problems need to be faced. Some kunukus currently have more livestock than their own parcels can sustain (Nolet et al., 2009). This would mean that as a result of this plan some people will have to sell a part of their livestock. Moreover, since livestock will not be able to feed itself sufficiently while being within the boundaries of the parcels, owners will have to buy food. Cooperation with and support from kunukus would be important for the plan to be successful.
Agriculture
Some kunukero’s use their land for agricultural purposes, to grow fruits and vegetables. In order to make the land suitable for this purpose, plowing needs to be done. This also causes more sediment to end up in the bay.
Figure 15 Plowing of the land can cause sedimentation.
Information on agricultural activities can be found through the developed questionnaire. From the information which has already been found with the 17 respondents no conclusions can be drawn. More respondents need to be found for a representative sample.