Day 7: Canoeing, Dr Bill Mitsch, Naples Botanic Gardens and invasive species 04/03/2016

Temperature: Max 25o C55

We had a late start this day and so explored the mangroves around the field station in the canoes. We were able to go into the smaller channels where the larger boats were unable to travel which meant we could get amongst the mangroves.  Despite this we bumped into another boat load of students so most wildlife would likely have been scared off. We did however see a mangrove tree crab (Aratus pisonii) and a sheepshead fish (Archosargus probatocephalus) which some fishers caught.

Dr. Bill Mitsch

After canoeing we headed off to a talk at the universities Everglades Wetlands Research Park (EWRP) by Dr. William (Bill) Mitsch a lecturer at FGCU and a leading wetlands scientist. The talk was titled “Climate change: What can wetlands do for us?” which outlined how wetlands are one of the best natural environments for the sequestering  and long term storage of carbon. In fact each year carbon sequestered by Florida’s mangroves equates to carbon released by 110, 000 car’s worth of emissions per year.

With 8-10 million km2 of wetlands and 3-4% of wetlands being mangroves and saltmarshes there is huge potential for carbon sequestration. The measurement of carbon sequestration from mangroves can be measured by how much carbon remains in the substrate below mangroves.  Disturbed areas generally have reduced carbon within the substrate and so carbon sequestration is lower in these areas.

We were however told that mangroves are in fact sources of methane due to the anaerobic sediments which they inhabit. Despite this  we were told that this was less import because methane decays in the atmosphere. We were also told that some climate scientists view wetlands as sources of green hose gasses due to lobbying from forestry and agriculture.

After this talk we walked over to the Naples Botanic Gardens that EWRP shares a site with.

 

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Silk floss tree (Celiba specios) to the left

Naples Botanic Gardens

The  botanic garden was founded in 1993 with much of the present garden having been purchased in 2000 and development completed by 2009. The gardens boasted a variety of themed gardens compiled of both native and non-native species. While exploring the garden we noticed many epiphytes including many orchid species, and a species of staghorn fern.  Another interesting plant species we came across was a silk floss tree (Ceiba specios) which had a trunk covered in thick, sharp prickles and  masses of fluffy silk-like matter in the canopy. 

The garden was also filled with wildlife with the common grackle (Quiscalus major), yellow-rumped warbler (Dendroica coronata) and grey catbird (Dumetella carolinensis) showing up.  Despite this we did come across some species we had not seen yet, with our first spot of a green anole (Anolis carolinensis) seen amongst a large bromeliad. We also came cross a red headed woodpecker (Melanerpes erythrocephalus) which we had not come across until this point.

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View within the botanic garden

After a short trip to the supermarket we had a “biology tailgate” with Win Everham (or a barbecue out the back of a pick-up truck, as us non-Americans may call it).

We then had a talk with Professor David Lodge from the University of Notre Dame titled “When nature bites back: solving the budget busting invasive species epidemic”

Invasive species talk

This talk discussed the logistics of dealing with many invasive species from a financial perspective of which the definition for invasive species was particularly important.

Non-native: a species which evolved elsewhere and arrived in a new location as a result of human intervention…

Invasive species: ‘’ … whose introduction does/ is likely to cause economic, environmental or human harm.

Therefore whereas all invasives are non-native, not all non-natives are invasive.

What the talk also considered was the reason why some species may have been intentionally introduced. For example Kudzu (Pueraria lobata), an invasive vine which is able to grow at a rate of 60 km2 annually. This leguminous vine native to Asia was intentionally introduced by farmers to reduce soil erosion and fix nitrogen into the soil. This has become an invasive with control costing $6 million annually.

The cost of invasive species within the US we were told was around $120 billion/year. With damages as a result of invasive species often exponentially increasing the longer an invasive specie remains. Therefore policy would be beneficial if it addressed an invasion before or as soon as it became a problem. However current policy generally waits until an invasion has occurred and negative impacts have begun showing.

Comparisons to the effective control of invasive human diseases were made with the 2003 SARS case, an effective example of management being made due a coordinated and rapid response. Whereas with invasive species there is a lack of global public infrastructure to respond to potential invasives.

A clear plan for the prevention and effective responses to an invasion were highlighted, summarised below.

  1. Species in pathway: prevent by species profiling to find whether a species will likely be harmful and ban its import.
  2. Transport: reduce species in pathways e.g. ballast water treatment.
  3. Released alive: early detection e.g. using environmental DNA (eDNA) to test for invasive presence easily followed by rapid response through fast eradication.
  4. Population establishment: control invasions that cannot be eradicated.
  5. Spread: worst case scenario.

This talk allowed us to get an insight into how decisions are made regarding invasive species, not necessarily from a conservation but from an economic perspective.

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