News « Forest & Sea Consulting

Coconut Palms are Going Feral

Coconut palms are the symbol of the tropics and people can hardly imagine tropical beaches without them. However coconuts were not generally found on Australia’s tropical shores and members of the public have taken to planting coconut palms along these coconut free beaches. The planted palms are now producing large numbers of coconuts which fall and germinate to form new coconut palms. Dense coconut thickets are forming and threatening to replace the endangered coastal rainforests of the Queensland coast.

A Coconut Thicket

Forest & Sea Consulting has prepared reports for coastal councils on the coconut issue. Most of the public can understand that coconuts have a place in the tropical landscape but need to be controlled in some situations. Some people so adore coconuts that they oppose any management of the species and this creates a difficult issue for councils.

In our work we have found three main issues:

coconuts replacing native vegetation;
where coconuts are on waterways, dead fronds can block storm water drainage systems; and
cost associated with de-nutting and public liability issues related to falling nuts.

Coconuts have two impacts on native coastal vegetation, firstly they out compete the native vegetation and take up space needed by the native species. Secondly, they change the coastal environment by creating a windbreak and shading the vegetation below. Exposure to strong wind is one of the main forces that create a unique coastal vegetation. When coconut break up the wind, the entire coastal forest changes. Generally only a few species can adapt to the change, mainly trees which can grow tall. The combination of less wind and tall shady vegetation means that most low growing species are lost.

Many coastal areas in north Queensland have beach ridges separated be swales or swamps. Coconuts often establish in these areas as well as on the beaches and create drainage issues. When storm water flows along the swales, it often encounters roads which have pipes or culverts installed to allow the water to pass. Fallen coconut fronds can collect and block off these storm water drains. Flooding of areas adjacent to the swale can occur when the pipes become blocked and the flood finds an alternate route. Damage can include flooded homes, flattened fences and gardens and erosion of road embankments.

In areas accessible to the public, mature coconut palms have to be de-nutted every few months. The process involves removing any developing coconuts from each palm and then removing the lower palm fronds so that any palms flowers which emerge after de-nutting will be exposed to full sun and will be burned and unable to set fruit. The cost of removing the nuts and leaves is enormous. Falling nuts can kill, so leaving the nuts to fall when they choose is not an option.

The solution would seem to be to only have coconut palms where they do not threaten the environment or the public, however the public is still planting coconuts everywhere.

The Source of Seagrass Tiles

A Seagrass Tile

One of the cheapest floor coverings around is seagrass tiles. I have always wondered where the seagrass came from and asked around to no avail. On a recent trip to Cape York Peninsula at the tip of Australia where I was doing an environmental survey (Cape Alumina project), I found a large sedge growing on the freshwater intertidal section of the Wenlock River. Formal identification revealed this sedge to be Actinoscirpus grossus. It took a lot of googling to connect this plant with the floor covering that it becomes.

Actinoscirpus grossus inflorescence

Greater Club-rush is the common name that seems to have the least potential for confusion. Actinoscirpus grossus has several common names, however these names are mostly in local languages as the sedge is found from Australia to Japan to India in both temperate and tropical climates.

This photo shows the inflorescence of the sedge which is held about 1 m above the water on a pithy triangular papyrus like stalk. In this habitat the tidal range is about 1 m and the sedge forms patches along the margins of the river. I very carefully collected a sample from here with a long stick which was just as well as I later saw a 4 m crocodile surface just beyond the sedges that would have been trying to collect me.

Actinoscirpus grossus in lower Wenlock River

Some web documents that I used to confirm my information are:

http://www.oswaldasia.org/species/a/actgr/actgr_en.html

http://202.90.141.226/publication/techno%20flyer/DYEING.pdf

http://www.agprime.com/Weeds/Invasive/FactSheets/Actinoscirpus%20grossus.pdf

Identifying Regional Ecosystems

Many court battles have been fought over regional ecosystem mapping. Andrew, the principal of Forest & Sea consulting was the lead consultant in the first test case under the Vegetation Management Act in the year 2000. More recently, he mapped wetlands associated the controversial proposed Cape Alumina mine near the Wenlock River. These challenging situations have provided reason to develop a comprehensive understanding of vegetation mapping process and a number of useful tools which are discussed below. Some of these tools are available to community groups and students on application (send an e-mail to Andrew@forestsea.com)

The Queensland Government’s vegetation mapping system is an ambitious attempt to map the vegetation across a region that is bigger than most of the world’s countries. Regional ecosystem mapping is simple in concept but it is often very difficult to determine which regional ecosystem (RE) you are standing in, when you are in the field. Some of the issues that Forest & Sea Consulting has encountered include:

determining which RE is present from a list of extremely similar REs;
vegetation that does not fit any RE description;
vegetation which does not fit any of the REs listed for an area; and
in determining whether vegetation is remnant or non-remnant.

As obtaining a reliable RE description for clients is often essential to being able to plan projects, we developed a tool kit for determining REs. The first thing to realise is that RE descriptions as presented in the Regional Ecosystem Definition Database (REDD) are derived from Corveg data rather than directly from observations made in the field. Features which catch the eye in the field are not always present in RE descriptions and conversely RE descriptions are heavy with features that do not stand out at all such as a ‘very sparse shrub layer’. The Corveg database contains all of the vegetation data collected in the field by Queensland Government botanists. The data it contains is based on measurements collected from a ’secondary vegetation’ transects usually 50 m long in which foliage cover and stem density and strata membership is recorded for each species. Site details such as slope, disturbance and soil are also recorded. Corveg has its roots in land system mapping, which pre-dates regional ecosystem mapping. In fact the Corveg system is indexed on a variety of vegetation mapping codes and is independent of the regional ecosystem framework. Regional ecosystem descriptions are based on a review of the structural and floristic information stored within the Corveg system for a particular vegetation aerial photo pattern. The practical implication of this is that when several similar REs are present, you really have to collect your own data in the Corveg format and then derive a structural and floristic description of the vegetation that is in the RE format, so that you can compare your RE description with the one from the REDD.

Collecting data in the Corveg format sounds like a lot of effort, however it has its rewards. Almost all of the words used in a RE description are defined terms rather than casual observations, for example the words ‘lower slopes’ refer to a landscape element that is defined in the Australian Soil and Land Survey Field Handbook. When it comes to distinguishing very similar REs, it is essential to be able to identify and understand the relevance of these defined terms. Every part of a RE description is derived from Corveg data and there are no wasted words so if anyone wishes to master the regional ecosystems, they should be prepared to invest time and effort into learning all of the species and the precise meanings of all the landscape element terms. Filling in Corveg data sheets ensures that you think about soils and subtle landscape features when you are still in the field.

The Queensland Herbarium has produced a guide on collecting data to Corveg standards which is available from them as a pdf document. The reference for this work is:

Neldner, V.J., Wilson, B. A., Thompson, E.J. and Dillewaard, H.A. (2005) Methodology for Survey and Mapping of Regional Ecosystems and Vegetation Communities in Queensland. Version 3.1. Updated September 2005. Queensland Herbarium, Environmental Protection Agency, Brisbane. 128 pp.

Unfortunately the guide has not been refined to the point where the entire process of documenting vegetation can be learned from it. It is an incomplete textbook and parts of it are written by people who should not be allowed to write textbooks. The gaps and issues only become apparent when you try to validate RE mapping using the Corveg or RE map modification process. The regional ecosystem process is also still evolving and progress is being made toward fixing some of the limitations of the system.

Does Big Name Software Help You?

Having the best computer equipment and best software is one of the easiest strategies to get an edge as it allows you to stand on the shoulders of the giants who dedicate their lives to making their products better, faster and cheaper. Most of the large consultancies that I have worked with hold onto their equipment and software until it dies from natural causes so having new equipment and software will give you an instant advantage.However new software also usually comes with disadvantages as well. Most industry standard software is too complex to learn in a hurry, even if you are a geek. In many cases I actually had to un-install the software from my computer to prevent it from further confusing my life. The lesson I learned is that it is far more productive to master simple applications and then graduate to industrial standard applications. In fact, most of the professionals started learning industry standard software in the early days when it was less complex and some of them admit it would be hard to get started with today’s applications.

Open source software is one of the best places to get simpler applications. Most of the popular open source applications have risen out of a crowd of tens of thousands of open source and freeware programs. The popular applications are popular because they are good, often as good or better than their commercial rivals. Often you will find that you will never need to go to an industry standard application as the simpler tools suffice or you find that hand coding is just as fast when you have learned how to.

For very complex work, commercial applications often have an advantage in that they have every feature under the sun and they have been optimised for speed. The core applications in which you do the bulk of your work should probably be a leading commercial offering, however even then, download and trial all of its competitors. In most cases, I have found that industry standard software is far from the best software in terms of speed, simplicity and not crashing. It doesn’t hurt to try before you buy.

Green Sea Slugs

Elysia bangtawaensis

Green sea slugs (Elysia bangtawaensis) are occasionally present in mangrove creeks in Australia. In fact these sea slugs have only once before been recorded in Australian waters and were originally found in Thailand. They eat algae but rather that just digesting the algae, they strip out the alga’s chloroplasts and keep them alive in tubes running from their stomach. The sea slugs become a green photosynthesizing animal that looks similar to a mint leaf and which can live for up to a year on photosynthesis alone. Although similar to sea slugs, nudibranchs are predators. More information about this species can be located at the Sea Slug Forum.

These sea slugs were observed during a personal project to document mangroves in Cairns region of Australia to see if mangrove zones are moving in relation to sea level rise. This project uses a large collection of georeferenced images to monitor events such as mangroves establishing in areas that are currently saltpans.