Project

Germination Biology

There is a lack of information on seedling germination biology for many endangered tropical trees of Bonaire. The methods that can be used to stimulate germination are also widely scattered through the literature and differ greatly depending on the type of seeds produced by plants.

The flora and vegetation of Bonaire has been and continues to be heavily influenced by human activities, resulting in large degraded areas with a very low presence of the original vegetation (ref. Debrot & De Freitas 1993, De Freitas et al. 2005). These areas have great difficulty in restoring their original composition and structure. This often results in shrublands with exotic species dominating the shrub and tree layers (Brandeis et al. 2009).

 To re-establish the natural biodiversity, nature needs some help by planting native trees and shrubs. These however are not readily available. Landscapers either have no interest in producing certain species, for instance because they are not suitable as garden elements, or they are not able to produce them.

Trees developed many strategies for their seeds to overcome the harsh conditions during dry periods. These includes very thick seed coats or pericarps, chemical regulation of seed dormancy (inhibitors), hormonal regulation of dormancy, special light requirements, rudimentary embryos that need a certain period of maturation, etc. Other species have seeds that cannot be dried or stored and need to be planted immediately (so-called recalcitrant seeds).

Brandeis et al. (2009) experimented with 10 species from Puerto Rico and the Virgin Islands, some of which are in common with or comparable to species from Bonaire, and had great difficulty in getting the seeds germinated. Very often scarification (filing off of part of the pericarp) and/or stratification were needed for longer periods. Germination of many took several months or they did not germinate at all.

Doelstelling

For 2014 the island govt of Bonaire wants to invest in a reforestation project. This follows several years of successful practical reforestation work by Carmabi and Stinapa as developed by A.O. Debrot of IMARES (Debrot 2013). Pooling of the available new information of seed germination  is critical to maximize reforestation efforts particularly with respect to several keystone and endangered plant species. The goal of this project is to assemble that information into a report so that it will be available as a solid basis for current and future reforestation plans.

Results

This deskstudy project will provide an overview of state of the art germination ecology and methods in support of reforestation efforts for the years to come.