Mother of Invention… a new tool to help save seagrasses

Submitted by Mike Burton, Principal (Sarasota, FL)

While ecologists are not normally known for their manufacturing skills, we are often confronted with the limitations of our tools. One particularly challenging problem we confront in coastal restoration projects is the vulnerability of submerged vegetation to removal and transplantation. Too often, even well-planned and executed restorations are undermined by an unacceptably high failure rate for some transplanted species, such as turtle grass, a species of seagrass. The problem isn’t always with the plan or methodology but can often be attributed to equipment shortcomings.

In the true spirit of “necessity as the mother of invention,” we set out to make a better mousetrap – or, in this case, a plug cutter. Over several years of iterative improvements, we devised a hand-held device to rapidly harvest, transport, and transplant deep-rooted seagrasses like turtle grass. So far, we’ve been encouraged by the results: our plugger has been shown to streamline the painstaking tasks of harvesting and transplantation while improving success rates and reducing costs.

This month we learned that the government agrees that the tool is a good thing—the United States Patent and Trademark Office issued Stantec a patent for what we’ve called our Submerged Aquatic Vegetation Plug Cutter.

Our model (you can see it in action on Stantec’s Facebook page) includes a manually operated plug cutter, a transport receptacle, and a related method for collecting and transporting plugs of vegetation or substrate core samples. Its defining feature: the use of compressed air, which releases vacuum pressure between the cutting body and the submerged substrate, thus separating the plug or core sample from the substrate with minimal effort. The pneumatic plugger also creates a hole to install the collected plug flush with the adjacent substrate.

The "plug cutter" in action

The receptacle used for transporting plugs includes a hollow cylinder constructed of PVC, with a removable bottom. The transport cartridge matches the length of the cutting member and has the same interior diameter, which maintains the integrity of the collected plug or sample. Both the plugger and transport receptacle can be fabricated to different diameters and lengths for various types of applications. To date, we’ve developed models from 6” (15.4 cm) to 8” (20.3 cm).

We build our equipment, as needed, at a local fabrication shop located in Florida. The pluggers are built to order, based on our specifications. Staff have refined the design several times based on field experience. The cost per plugger is approximately $1,000 each depending on size and the materials required.

In October of 2007, we transplanted 1,001 plugs of turtlegrass using the plugger. Results from the monitoring of the transplanted units indicated an unprecedented 75% survival after 3 years. To date, we’ve been able to use this method to successfully transplant over 20,000 units of seagrass.

We are now tracking the success of the plugger on an ongoing basis via our contracted seagrass restoration and transplantation assignments. We’re confident that the tool, when made part of a comprehensive plan, can result in less impact to the donor site, more rapid transplantation, and a higher survival rate.