vegetation

Dutch Caribbean species distribution

The distribution is presented in 1 km-grids, based on vegetation relevés and digitized data from herbarium specimen, photos, literature and field surveys. Releves date back to 1880.

Date
2022
Data type
Portal
Theme
Research and monitoring
Geographic location
Aruba
Bonaire
Curacao
Saba
St. Eustatius
St. Maarten
Image

Vegetation Study informs Spatial Planning on Sint Maarten

Commissioned by Sint Maarten’s Ministry of Public Housing, Spatial Planning, Environment and Infrastructure (VROMI), a color vegetation map produced by CARMABI and Wageningen University & Research shows a 25% decrease in overall vegetation cover of the Dutch side of the island since 1956.  Results show that this loss can be attributed to massive urbanization and touristic development, overgrazing by introduced mammals (goats), the impact of hurricanes and the negative effect of invasive plant species. By investigating and mapping the vegetation of the island, spatial planning strategies can work to protect and connect the remaining sensitive landscape ecological units, to prevent further loss of biodiversity and vital natural resources.

 

Usefulness of vegetation maps

Credit: Marjolijn Lopes Cardozo: SHAPE/DCNA

Vegetation maps are a useful tool in understanding the status of the biodiversity and species make-up of a particular area (e.g. of an island). These maps are used by a wide variety of actors, -from scientists to policy makers- and are key to spatial planning and designing nature management and conservation strategies. This gains extra relevance based on the fact that St. Maarten is a biodiversity hotspot in the Caribbean area: the island is inhabited by over 100 species which can only be found within the Lesser Antilles region and 12 species which can only be found on St. Maarten.  Furthermore, the vegetation types that are associated with the hilly landscape (the dominant landscape of St. Maarten) belong to the most threatened ecosystems in Latin America and worldwide.

A well-developed natural vegetation plays a critical role in securing balanced and healthy ecosystems. Areas with such a vegetation influence soil properties, prevent erosion, aid in water retention and provide important buffers between land and sea (preventing damage to coral reefs by sedimentation).  Not to mention the importance they play in providing food and shelter for a wide variety of the island’s native animal populations.

Changes in the islands’ natural vegetation since 1956

Credit: Christian König: SHAPE/DCNA

The results of an island-wide field study done at the end of 1999 shows that in comparison to a vegetation map published in 1956, a 25% decline in vegetation cover has taken place. In addition, five different vegetation types -found in coastal areas- have disappeared beyond recognition over those 40 plus years.  The interconnectedness of ecosystems on islands make them vulnerable to the impact of habitat loss and fragmentation as well as the negative impact of grazing by introduced mammal grazers and invasive plant species. Of course, we must not forget the detrimental effects of hurricanes and global warming.

Over time, habitat loss and fragmentation on St. Maarten have been caused by agriculture, grazing by introduced mammals and since the 1960s by an explosive growth in tourism. Particularly since 1980 tourism has skyrocketed on the island. Some vegetation units described in 1956 have also disappeared due to actual vegetation regeneration and succession to a more diverse state following the decline in agriculture and livestock grazing.

Although there has been some regeneration, the overall process witnessed for St. Maarten is that of loss of natural and semi-natural vegetated areas in all parts of the island. The largest disappearance took place in the western parts of the island that in 1956 were characterized by the presence of two evergreen vegetation types. In the Low Lands area, a climax evergreen vegetation type covering a large part of the area in 1956 has disappeared almost totally except for a very small area still present but seriously threatened. Large areas of a vegetation type with a deciduous character to the west of the eastern hill range have been lost. One could observe that the general trend shows that the hills are regenerating while the low and coastal areas are degrading at a faster rate, resulting in a net vegetation loss. This trend demonstrates the economic shift from mainly agricultural practices towards an economy heavily reliant on tourism.

Towards a more sustainable future for St. Maarten

Vegetation maps similar to the one produced in the present report have been completed by Carmabi for other Dutch Caribbean islands as well.  This includes maps of Curaçao (1997), Bonaire (2005), St. Eustatius (2014) and Saba (2016).  Since the 1980’s land-use planning has become a hot topic, and understanding the current status of each island’s terrestrial areas is critical in both sustainable land development as well as implementing conservation and restoration strategies moving forward. The report ends with five recommendations to works towards a more effective terrestrial nature management on the island: establish a protected areas network, control of roaming livestock, protection of endangered plant species, an invasive species action plan and long-term vegetation monitoring. Findings of this report point to the importance of protecting and connecting rare and individual landscape units, such as those found in the Low Lands and at the remaining naturally vegetated beaches. It is also clear that the landscape ecological units that are characteristic of the high hills have a high conservation value that call for protection.

For more information, you can read the full report here

https://www.dcbd.nl/sites/default/files/documents/landscape_ecological_v...

 

Article published in BioNews 46

 

Date
2021
Data type
Media
Theme
Education and outreach
Research and monitoring
Geographic location
St. Maarten
Author

Intervention Needed to Save the endemic Sabal Palm of Bonaire

An update to a 40-year-old Sabal palm survey for the islands of Bonaire and Curaçao highlighted the striking differences between the two islands. Through active park management, Curaçao has seen over more than a three-fold increase in adult Sabal palms, whereas an unmanaged palm population on Bonaire has seen a decrease of nearly 20% of adult palms. Actively protecting these valued endemic palms may be the only way to ensure their future.

 

The Sabal palm, or Kabana as it’s known locally, is the only native species of palm tree found on the islands of Bonaire and Curaçao. In fact, the true identity of this palm has been heavily debated, with its classification changing throughout the years until it was finally recognized in two scientific publications as two endemic species Sabal antillensis on Curaçao, in 2017, and on Bonaire Sabal lougheediana, in 2019.

On both islands the Sabal palm population is found in very limited distribution areas. On Curaçao, its range is limited to the highest hills in the southwestern part of the Christoffelpark and its direct surroundings there. On Bonaire, this palm is only found within the Lima area, the very low limestone terrace located west of Lac Bay and north of the salt pans.

Photo credit: © John de Freitas

In 1979, researcher J.E. Winkelman first surveyed  the number of palms on both islands, which she found to be 1,062 specimens in total. Of these, only 354 were mature palms, and only 31 of these could be found on Bonaire. In this initial study, Winkelman also noted that the largest threat to these remaining palms was most likely free roaming animals, such as goats and donkeys, who could eat and trample seedlings. Since this initial assessment, no follow-up surveys have been conducted, creating a significant knowledge gap concerning the current status of these iconic palms.

Luckily, a new study worked to close this gap. Researchers documented current populations on both islands and compared these results to the initial 1979 survey. The goal was to not only provide an updated count, but also note if any change to their range have occurred, providing important insight into factors that will contribute to designing an effective conservation strategy.

The Study

In 2018, surveys were conducted by counting the number of palms on each island. Given the small geographical areas and uniqueness of the terrain, it was generally easy to find and spot these palms. By using similar techniques and survey sites, a direct comparison between the 1979 and 2018 studies could be completed to help evaluate the local populations as decreasing, stable or increasing.

Interestingly, populations on these two islands have had very different developments over time. There has been  a 318% increase of adult palms on Curaçao, whereas Bonaire has seen a decrease of approx. 20%. In addition to population changes, there was also fairly significant shifts in their range as well. On Curaçao, the overall geographic range of these palms increased, from less than 5 km2  in 1979 to 8 km2  in 2018. Again, Bonaire saw a very different trend, with the geographic range shrinking from 5 km2 to less than 1 km2.

Other results

For both islands, there were a relatively large number of seedlings seen through their geographical range. On Curaçao, this could have been the result of the increase in  adults. On Bonaire, it is more likely attributed to the time of year the surveys were conducted. The 2018 survey was conducted right after the wet season, which could account for the increase in the number of seedlings due to the fact that fresh seeds germinate quite easily.

Changes in overall numbers of palms can be attributed to a wide range of factors. Christoffelpark has actively managed their goat and donkey populations since the mid-1980s. This decrease in free roaming grazers may have given these palms a higher probability of survival. These grazers have been known to feed on and trample seedlings, along with reducing vegetation and soil cover, further threatening the ability of seedlings to successfully grow. The increase in Curaçao’s range could have been due to the successful dispersal of seeds by local animal populations, as there are various species of birds, deer, rodents, and iguanas inhabiting this area and are known to feed on these seeds.

Recommendations

The findings of this study have led the researchers to provide four key recommendations for designing a successful conservation strategy for these palms. First, they recommend actively managing feral herbivores within the palm’s habitat. On Bonaire, this could be the construction of a 3.5 km long fence which runs along the perimeter of the Lima area in order to enclose the whole Sabal palm population in the Lima area.

Second, they recommend implementing a more rigorous monitoring plan to help track the health and recruitment of these palms to provide key indicators of change in future populations. Third, it has been recommended that Bonaire actively cultivates these palms in other areas of Bonaire, to improve overall population numbers. Lastly, the successful management program of the Christoffelpark should be continued, as this study shows the dramatic impact significantly reducing the number of feral grazers can have.

Future of the iconic Sabal palm

The free roaming animals of Bonaire are often part of the iconic charm of the island. A successful future of the island’s endemic species, both plant and animal, must include a balance to allow each a chance to thrive based on nature’s ecological capability. This study demonstrates how actively managing these feral animals can drastically improve the flora populations of the island. Understanding the impact each species has on the ecosystem will help nature management organizations design and implement environmental management plans to ensure a healthy future for the island.

For more information

Freitas, J. de et al. (2019). Sabalpalm (Sabal antillensis) Recovery Over 40 Years: Lessons for Successful Palm Conservation. PALMS Vol. 63(2): 57-68.

 

 

Article published in BioNews 41

Date
2021
Data type
Other resources
Theme
Education and outreach
Research and monitoring
Geographic location
Bonaire
Curacao

Analysis of vegetation change for two coastal regions on Curaçao

Island ecosystems are vulnerable to the influence of goats which are invasive to most islands and are considered the most damaging for island vegetation. High grazing pressure has also been a challenge for the island of Curaçao which decided to remove goats from the Christoffelpark between the late 1980s and early 1990s. After almost 30 years of grazer absence and with no vegetation mapping campaigns in the park, vegetation maps created prior to the exclusion of goats were not representative anymore. Therefore, the vegetation was re-mapped in 2018/19 to analyse changes in vegetation. Results showed evidence of vegetation regrowth in the Christoffelpark. However, the rate of vegetation regrowth and when it first occurred in time was still unknown. This thesis aimed to gain understanding in the 30 years without vegetation data from the field and to compare effects on vegetation trends in areas where grazers are still present (Shete Boka National Park) and where grazers have been removed (Christoffelpark’s coast). Vegetation succession was found in the Christoffelpark’s coast with a decrease in coverage of grasses and herbs and an increase in coverage of trees and large shrubs. Contrary results were found in the Shete Boka park where grazing pressure is still high. Landsat satellite imagery were used time series analysis between 2000 and 2020 to get insight in vegetation trends. Based on a pixel-wise Mann-Kendall trend test, no perfect monotonous trends were found and only 10 vegetation communities showed a significant trend with 7 located in the Christoffelpark’s coast. Change detection analysis was performed to detect shifts in vegetation trends. The LandTrendr algorithm and the bfast01 algorithm showed contrary results. Considering the TWINSPAN vegetation communities, the LandTrendr algorithm detected an average of 18 breakpoints in the Christoffelpark’s coast and 13 breakpoints in the Shete Boka National Park whereas the bfast01 algorithm detected two breakpoints in the Shete Boka park and none in the Christoffelpark’s coast. The contrary results make it difficult to explain the drivers behind the detected breakpoints, especially as the period shortly after the exclusion of goats has not been part of the analysis. Further research is recommended to assess vegetation dynamics prior to 2000 as shifts in vegetation growth may have occurred more closely to the exclusion of goats in the Christoffelpark.

[MSc thesis report]

Date
2021
Data type
Research report
Theme
Research and monitoring
Report number
GIRS-2021-18
Geographic location
Curacao
Author

The vegetation of the Netherlands Antilles

This vegetation survey is the outcome of an investigation of the islands of the Netherlands Antilles carried out under the auspices of the Foundation for Scientific Research in Surinam and the Netherlands Antilles. The data on which the present study is based were obtained during a trip which lasted from September 1952 until October 1953. During this trip the following islands were visited: Curaςao, Bonaire, Aruba, St. Martin, Saba, and St. Eustatius. A short visit was also paid to the island of St. Kitts (B.W.I.).

Date
1956
Data type
Research report
Theme
Research and monitoring
Geographic location
Aruba
Bonaire
Curacao
Saba
St. Eustatius
St. Maarten

Botanisch onderzoek van de Nederlandse Antillen

Botanisch onderzoek van een gebied heeft als regel in drie fasen plaats:

  1. floristisch onderzoek, teneinde een overzicht te krijgen van de plantensoorten, variëteiten en andere systematische eenheden die in het betreffende gebied gevonden worden;
  2. vegetatie-onderzoek, om een overzicht te krijgen van de samenstelling van het plantendek;
  3. oecologisch onderzoek, om tot een causale verklaring van die vegetatie te komen.

Deze drie fasen zijn in de Nederlandse Antillen ook te onderscheiden en zullen daarom achtereenvolgens besproken worden

Uitgewerkte lezing gehouden op 27 november 1965, ter gelegenheid van het 20-jarig bestaan van de 'Natuurwetenschappelijke Studiekring voor Suriname en de Nederlandse Antillen.

Date
2021
Data type
Book
Theme
Research and monitoring
Geographic location
Aruba
Bonaire
Curacao
Saba
St. Eustatius
St. Maarten

Moss flora and vegetation of Saba and St. Eustatius (West Indies)

The known moss flora of the small West Indian island Saba (870 m in altitude) consists to date of48 species, while the neighbouring island St. Eustatius (600 m) has 40 species. The two islands have 27 species in common. Widely distributed neotropical species dominate at all elevations, while wide-tropical (i.e. pantropical) species are found mainly at middle elevations (300-600 m). Species with smaller geographical distributions (southern neotropical, Caribbean) are restricted to higher elevations (above 600 m).

An attempt has been made to determine the relation between mosses and the plant communities, encountered along the altitudinal gradient, by calculating “association values”, based on the results of random collecting. Four classes of association values have been distinguished: class A: very characteristic; class B: characteristic; class C: moderately characteristic; and class D: non-characteristic species. It appears that eight plant communities on both islands harbour one or more moderately to very characteristic species. Neckeropsis undulata is the only very characteristic species. It occurs in the evergreen seasonal forest on St. Eustatius. The results are compared with Guadeloupe, Martinique, Puerto Rico, Guyana and Suriname. Finally, a key to the species is included.

Date
1984
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Saba
St. Eustatius
Author

WSNP Monitoring Protocol

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.

Data type
Monitoring protocol
Theme
Education and outreach
Research and monitoring
Geographic location
Bonaire
Image

Vegetatie onderzoek Bonaire 2019

This report describes a field visit to the Caribbean island of Bonaire aiming at collection of field data on the arid vegetation, which consists largely of dry thorn scrub, cactus scrub and dry tropical forest. Vegetation releves have been amde at 23 sites, among which eight sites that have been surveyed in 1999. Besides 50 short field descriptions have been made as a basis for a land-use map. The report describes how the more than 1000 releves of the Dutch Caribbean islands, which are stored in the vegetation database CACTUS, may be analysed to provide insight in natural processes like vegetation succession and effects of land use, climate change and other factors. Besides, the report contains an advice for the representative Ministry of Agriculture, Nature and Food Quality on the island about the (better) conservation of sites on the limestone terraces with very well developed woodland.

Date
2020
Data type
Research report
Theme
Research and monitoring
Report number
3047
Geographic location
Bonaire
Image

Landscape map Bonaire

Landscape map that depicts the intersections of biophysical, cultural and aesthetic characteristics, delineating landscape types to which coherent sets of nature-inclusive measures are assigned. This landscape map was developed using clusters of nature-inclusive measures that were spatially located by local experts on a map of Bonaire, in combination with geological, soil , elevation , vegetation , planning and high resolution land cover maps.

See this report for more information.

Date
2020
Data type
Maps and Charts
Theme
Research and monitoring
Geographic location
Bonaire
Image