soil

This document contains the written guidelines of the monitoring project in the Washington-Slagbaai National park of Bonaire. These monitoring guidelines are a product of BonBèrdè, an independent consultancy business focussed on nature conservation on the island of Bonaire. This document is requested by and written for STINAPA. The monitoring protocol will consist of a background information paper that includes all general information about the protocol as well as factors to be studied in the field. This is the Monitoring protocol. In addition to this document, a field guide is provided. The Field guide can act as a quick check in the field which will provide fast guidelines to the exact measurements of the monitoring itself.

As STINAPA is currently aiming to remove invasive herbivores from the Washington-Slagbaai National park, the goal of the monitoring project is to assess the current state of the ecosystem inside the park and keep measuring the possible changes over time, following the gradual removal of these animals. With the removal of invasive herbivores, the ecosystem viability is expected to increase and result in a positive succession and regeneration of native trees. However, these expectations will have to be measured in order to prove the necessity of invasive species management. The monitoring protocol can provide STINAPA with the tools to measure the changes in the park over time, using indicators of the possible regeneration. These indicators include:

• Vegetation
• Soil
• Fauna

The monitoring protocol will include the exact indicators and factors that can be measured to assess the ecosystem's succession over time. Furthermore, the field guide will provide STINAPA with the manual on how to execute the monitoring in the field. All the methods and proposed actions in these documents are focused to achieve the best results while taking into account that the methods should be practical to implement and replicate by STINAPA personnel.

Scan of paper soil potemtiality map of Aruba

Scan of paper soil map of Aruba

Invasive species are known to alter ecosystems all over the world. On the island of Bonaire, domestic goats (Capra hircus) were introduced in the 16th century. Today, their descendants occur on the entire island in the form of feral species and free roaming domestic animals, grazing and browsing on various plant species. Considering that goat trampling behaviour may cause topsoil structure amelioration and restriction of infiltration, it is likely that the goats on Bonaire increase the island’s susceptibility to erosion by mechanical disturbance. Bonaire likely had a climax vegetation of dry tropical forest in the past. However during the last centuries woody species and tall columnar cacti are diminishing and the vegetation on the island is largely transformed into a cacti-dominated scrubland with large expansions of bare soil.

A long term goat exclusion experiment in Washington Slagbaai National Park was set up 9 years ago. Recent research here has already shown that goat exclusion increases vegetation recovery. Apart from direct herbivory effects, the vegetation may also benefit from improving soil hydrological conditions resulting from eliminating goat herbivory and trampling effects. The aim of this thesis was to determine the role of goats on soil hydrological properties though conducting water-runoff simulations and infiltration tests. 9 year goat exclusion did not result in a difference in water and sediment runoff quantity. The litter percentage inside exclosures was higher, correlating with a lower soil temperature and higher soil moisture content. Where goats have access we found a higher amount of organic matter runoff, meaning that relatively more organic matter is retained inside the exclosure in case of a rain event. This shows us that goat exclusion is likely to play a role in the soil’s capacity to recover nutrient levels and soil moisture content.

Msc.thesis

The land capability map of St.Eustatius is produced by the Netherlands Antilles Development advisory bureau (Amsterdam) for the foundation of the welfareplan for the Netehrlands Antilles (1946, Curacao) at a scale of 1:25.000.

The land capability map of Saba is produced by the Netherlands Antilles Development advisory bureau (Amsterdam) for the foundation of the welfareplan for the Netehrlands Antilles (1946, Curacao) at a scale of 1:25.000.

The historical soil map of Bonaire has been produced for the ministry of welfare of the government of the netherland antilles as part of the development plan on land and water at a scale of 1:40.000.
The download includes a hi-resolution scan of the original paper map and a geo-referenced version for use in GIS.

 

Soil map of Saba (GIS) based on historical paper maps updated from field surveys.

Soil map of St. Eustatius (GIS) based on historical paper maps, updated from field surveys.

Soil map of Bonaire (GIS) based on historical paper maps updated from field surveys.