This week's guest blogger is Dr. Carin Bondar.  She is a biologist, writer and film-maker with a PhD in population ecology from the University of British Columbia.  In addition to her biology blog, she recently released her first book ‘The Nature of Human Nature’, a light-hearted look at where the human species fits in with the rest of the animal kingdom.  Find Dr. Bondar online at www.carinbondar.com, on twitter @drbondar or on her facebook page, Dr. Carin Bondar – Biologist With a Twist.

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The practice of silviculture has been alive and well in the terrestrial ecosystems of our planet for a few centuries.  From Latin roots, the term essentially means to grow (culture) the forest (silvi).  Such a practice has made both economic and ecological sense in a myriad of biomes on each and every continent.  After all – if the world’s forests are somehow degraded (most often by anthropogentic disturbances) it makes a lot of sense to have a number of techniques by which to restore them.  As I mention above, silvicultural practices like ‘human assisted natural regeneration’ of forests are both well researched and successful in terms of their goals of re-growing terrestrial forested stands.  Researchers recently asked whether such methodologies could be applied to their aquatic counterparts: the world’s coral reefs

It’s no secret that coral reef habitats are in peril due to the seemingly limitless human-caused stresses they face.  From directly poisoning them with our agricultural runoffs and sunscreens, to choking them with sediments resulting from near-shore construction/deforestation, to bleaching them with increased temperatures and acidity levels, there is no shortage of anthropogenic abuse faced by these precious animals.  It’s important to recognize that the death of the corals themselves is one issue – but loss of coral reef ecosystem represents so much more.  Thousands of other species depend on coral reefs for all aspects of their lives (habitat, food, population and community interactions) making these areas among the most ecologically important habitats in the world. In the face of such drastic environmental degradation, where traditional passsive conservation practices (e.g. the designation of marine protected areas (MPAs)) don’t seem to be enough to reverse the catastropic cycles of coral death, researchers are exploring techniques to actively increase coral growth.  A group of scientists from the Isreal Oceanographic and Limnological research institute and the University of Haifa have been working on a ‘Gardening Coral Reef’ methodology for a number of years, and results of their initial experimental work look extremely promising.

The ‘gardening’ concept involves the transfer of nursery-farmed coral colonies to areas of reef degradation.  I was first introduced to this kind of process in another really encouraging writeup on the future of coral reefs by Dr. Al Dove, who describes a similar effort by the Coral Restoration Foundation taking place in South Florida.  Transplantation of 1400 nursery-farmed colonies (of seven different species) to polluted reef areas in Eliat, (Red Sea, Isreal) took place in 2005, 2007 and 2008.  Colonies were seeded from Eliat reef specimens, and reared in a floating nursery in the Red Sea at a safe distance from environmental degradation and under protection from coral-predators.  After 8 – 24 months in the nursery, coral ‘nubs’ were transplanted and monitored for survivorship and (more importantly) for reproductive potential.  Four years after being transplanted, both the engineered and the natural colonies were assessed and compared.

Figure 1 Caption: (A) A gravid transplant, 3.5 years after transplantation. White bar = 2 cm (B) planulae-collection device placed over a transplanted colony in the restored reef.

The number of planula larvae produced during a 24 hour period in the reproductive season was the selected measure by which comparisons were made (see figure 1).  Planulae collection devices were placed over the sample corals (one of the seven transplanted species), and the larvae were filtered out and quantified.  Here comes the good news:  a significantly higher percentage of transplanted colonies produced larvae than the unassisted ‘natural’ colonies, and direct comparison of the gravid specimens of both transplanted and natural corals showed that the transplanted specimens produced a significantly higher number of larvae.  Now, the results of this study don’t actually assess the viability of the larvae produced by both colony types; however, the fact that after a period of 4 years the transplanted colonies are surviving, thriving, and producing a significant number of healthy larvae is extremely encouraging.  Future steps in this on-going project will include both a reef-scale assessment of coral growth in supplemented areas and investigation into the viability of the larvae from both transplanted and natural specimens.

This work represents one of the first data-sets to demonstrate the long term effects of farmed coral colony transplantation.  It makes a lot of sense to me – if coral reefs can benefit with the addition of reproductive-ready farmed colonies, this kind of practice should become widespread.  By comparison, the forestry industry is one that depends on healthy forests – so re-planting and re-seeding is part of the harvesting process.  Foresters don’t simply wait for forests to re-grow on their own (the functional equivalent of designating an MPA and allowing the corals to restore themselves), they actively replace what has been taken in order to keep the resource sustainable*.  Why not apply the same mentality to the coral reef?  Sure, we aren’t ‘deforesting’ the coral reefs as an economic enterprise like the timber industry, but we certainly have a responsibility to ensure the continued functionality of these vital ecosystems - especially since we are the ones who are wrecking them in the first place.

*The point of my argument here is that in many cases responsible forestry practices involve re-planting and re-seeding.  There are, of course, numerous accounts and examples of destructive and degradative clearcutting that do no such thing – creating environmental and ecological devastation.

References

Horoszowski-Fridman, Y., Izhaki, I., & Rinkevich, B. (2011). Engineering of coral reef larval supply through transplantation of nursery-farmed gravid colonies Journal of Experimental Marine Biology and Ecology DOI: 10.1016/j.jembe.2011.01.005