bese-element

Abstract

This thesis assignment consists of two parts: mapping mangrove planting sites along the southwest 
coast of Bonaire, and comparing and evaluating the outplanting with the BESE-elements® mangrove 
restoration techniques.

The Mangrove Maniacs asked to map the mangrove planting sites along the 
southwest coast as part of their mangrove restoration project. The focus was mainly on the large 
planting sites with a couple of hundred mangrove seedlings planted close to each other. The planting 
pattern of each planting site is random, so maps of the planting sites were needed to create an 
overview of each site. However, an efficient way to map the large numbers of mangrove outplants 
had to be found to create the maps. So, the objective of the mapping part of the thesis assignment 
was to find an efficient way to map the large mangrove planting sites along the southwest coast of 
Bonaire. The maps can be used to track the success rate of the mangrove restoration project, support 
outplant monitoring, identify potential planting areas, and use the maps in publications and on social 
media. The type of research that was involved was fieldwork. 

The second part was focused on the outplanting and BESE-elements® mangrove restoration 
techniques. Since the start of the mangrove restoration project, the Mangrove Maniacs have used 
the standard outplanting technique. However, there was still a knowledge gap in the success rate of 
the outplanting technique at the different planting sites. Apart from the outplanting, the BESE- 
elements® restoration technique was introduced to the mangrove restoration project by a WUR MSc 
Forest and Nature Conservation student. The Mangrove Maniacs asked to include the BESE- 
elements® in this thesis assignment and continue monitoring the red mangrove propagules planted 
in the BESE-elements®. The BESE-elements® mangrove restoration technique was included to see if it 
has the potential to improve the mangrove restoration project along the southwest coast of Bonaire. 
The types of research that were involved were literature study and fieldwork. The two main 
questions are: What is the most efficient way to map different mangrove planting areas, focusing on 
large planting sites, to provide an overview of the success rate of the mangrove restoration project 
along the southwest coast of Bonaire? And how can the mangrove restoration project along the 
southwest coast of Bonaire be improved? The research method that has been used for the mapping is 
fieldwork. A 5 by 10 metres grid was used to map the large numbers of outplants. This grid was 
drawn on-site, and the digital maps were created with GIS in ArcMap. The research method for both 
the outplanting and BESE-elements® techniques was fieldwork. The survival and growth rate of the 
outplants were monitored biweekly. Survival of the propagules in the BESE-elements® was 
monitored once a week and the growth once a month. An Anova test was conducted for the 
outplants to see if the relative growth rates of the planting sites differed significantly from each 
other. T-tests were conducted for the BESE-elements® and control sites for each study site's survival 
and relative growth rates. Two types of maps have been created. Based on the grid, heat maps were 
made for the large planting sites. In comparison, the smaller planting sites were mapped without a 
grid. The survival rate of the red mangrove outplants at the different planting sites is generally high. 
The Anova Single Factor test showed no significant difference between the relative growth rates of 
the tagged outplants at the nine planting sites (p=0.137). The lowest average survival rate of all BESE- 
elements® and control sites was at a BESE-elements® site. The results of the t-tests showed that the 
survival and relative growth rates are not significantly different between the BESE-elements® and 
control sites at all four study sites. In conclusion, a grid was the most efficient way to map large 
planting sites with outplants planted closely together. Drawing a grid has low costs, but it is time- 
consuming. Research on more sophisticated mapping methods is needed if the planting sites grow 
significantly in the future. The BESE-elements® showed no significant difference between survival 
and growth rate regarding the control sites in the short term. So, long-term monitoring is necessary 
to see if the BESE-elements® merit the time and financial investment.