UNDERSTANDING THE ROLE OF HERBIVORY AND PREDATOR/PREY INTERACTIONS TO GUIDE THE DEVELOPMENT OF A COMPREHENSIVE CORAL

REEF RESTORATION STRATEGY

William Sharp and Gabriel Delgado

Florida Fish & Wildlife Conservation Commission Fish & Wildlife Research Institute

2796 Overseas Hwy, Suite 119 Marathon, FL 33050

1965

1979

1988

2001

2010

Images: Gene Shinn. Tropical Treasures - South Florida Marine Environments

2002

From: Gardner et al 2003

Present Situation of Florida’s Coral Reef Ecosystem

Florida’s coral reefs have become degraded due to numerous stressors

Coral diseases Loss of dominant herbivore Poor water quality Marine debris Climate change

What can we do?

Manage to maintain biodiversity —Establish Marine Protected Areas

Reduce land-based sources of impact

Reduce direct impacts from human usage

©CRF/Tim Grolimund

But is this enough?

Increasing acceptance that restoring Florida’s coral reef ecosystem will require active restoration efforts

©CRF/Tim Grolimund

Coral Restoration

Restoring the physical reef structure is the necessary first step toward coral reef ecosystem restoration

Coral Nurseries We have established two coral

nurseries in the middle Florida Keys

Part of a network of nurseries throughout Florida and the Caribbean

Stocked with staghorn coral

Herbivory ‒ Long-Spined Sea Urchin Research

Other Coral Reef Ecosystem Restoration Research

Predator/Prey Dynamics – Corallivorous gastropods & a potential predator

Herbivory ‒ Long-Spined Sea Urchin Research

Other Coral Reef Ecosystem Restoration Research

Predator/Prey Dynamics – Corallivorous gastropods & a potential predator

Long-Spined Urchin Research

Diadema antillarum

Keystone coral reef herbivore

Caribbean-wide mortality event in 1980s

Recovery identified as necessary to improve health of coral reef ecosystem

Importance of the species

Long-Spined Urchin Research

2009 – A cohort of Diadema successfully cultured to early-benthic-juvenile stage

Can hatchery-produced Diadema be used as part of a comprehensive coral reef ecosystem restoration strategy?

First question -- Are hatchery-produced individuals ecologically competent?

Sheltering Behavior

D antillarum typically exhibit diurnal sheltering behavior

Compare sheltering behavior of initial hatchery-reared cohort & wild individuals

Laboratory trails in mesocosms with shelter provided

Replicated trials with wild and hatchery urchins in separate mesocosms; Trials with wild and hatchery urchins in the same mesocosms

15 cm

Sheltering Behavior

Day 4 3 2 1

perc

enta

ge in

shel

ter (

+ 1

se) 100

50

0

Night 4 3 2 1

wild hatchery

wild & hatchery in separate mesocosms

P = 0.008 NS

Behavior - Shelter Usage

wild & hatchery mixed in same mesocosm

P = 0.003

5 4 3 2 1 5 4 3 2 1

Day Night

perc

enta

ge in

shel

ter (

+ 1

se) 100

50

0

P = 0.045 wild hatchery

Behavior - Shelter Usage

Behavior - Shelter Usage Next hatchery-bred cohort

Shelter provided until

transported to FWC lab ~ 5 mm test diameter

Behavior - Shelter Usage

“Shoebox Experiments”

Hatchery-bred urchins given appropriately scaled light/dark choice

Behavior - Shelter Usage “Shoebox

Experiments” Hatchery-bred

urchins given appropriately scaled light/dark choice

Observed diurnal differences in sheltering behavior

5555 5555N =

DATE

06/05/1106/04/1106/03/1106/02/1106/01/11

Mea

n (+

- 1 S

E) %

in S

helte

r

1.2

1.0

.8

.6

.4

.2

0.0

Day

Night

Behavior - Shelter Usage Shoebox - Day Shoebox - Night

NS NS

Long-Spined Urchin Research Chemotactic responses to predation threat

Wild urchins will avoid the water-borne chemical signal of a predator

From Kintzing 2010

Approach modeled after Kintzing (2010) Tracked overall movement

of hatchery-bred urchins in response to lobster chemical cue

Chemotactic Responses to Predation Threat

Chemotactic Responses to Predation Threat

Hatchery-bred responded similarly to wild urchins as reported by Kintzing (2010)

Summary Sheltering Behavior

Grow-out conditions affect sheltering behavior; juvenile urchins deprived of shelter do not exhibit diurnal sheltering behavior

When provided appropriately scaled shelter during the husbandry process, hatchery-bred urchins exhibit expected diurnal sheltering behavior

Density-dependent effects are being evaluated

Chemotactic Responses to Predation

Hatchery produced urchins behave as wild individuals when exposed to the water-borne chemical signal from a potential predator

Long-Spined Urchin Research

Culturing Diadema to the early-benthic-stage remains highly problematic

We have a long way to go

Can we successfully translocate wild urchins onto restoration sites?

Long-Spined Urchin Research Does the degraded condition of the offshore reef bank provide sufficient habitat to support an ecologically functional population of Diadema?

Long-Spined Urchin Research Can artificial habitat increase survival rates?

Long-Spined Urchin Research Can artificial habitat increase survival rates?

Long-Spined Urchin Research Can artificial habitat increase survival rates?

Long-Spined Urchin Research Can artificial habitat increase survival rates?

Long-Spined Urchin Research Successful re-

establishment of long-spined urchins on highly degraded reefs will require habitat enhancement

Examine Staghorn coral/Diadema interaction

Herbivory ‒ Long-Spined Sea Urchin Research

Other Coral Reef Ecosystem Restoration Research

Predator/Prey Dynamics – Corallivorous gastropods & a potential predator

Impacts of snail predation upon both outplanted corals used in restoration and remnant wild colonies can be profound

Snail Predator Prey/Dynamics

Snail Predator Prey/Dynamics

We are investigating the predator/prey dynamics of these corallivores and a predatory snail, Thais deltoidea

Snail Predator Prey/Dynamics T. deltoidea readily

prey on corallivorous snails in the laboratory Is this trophodynamic

ecologically relevant?

‒ Prey preference ‒ Size-specific prey

selectivity ‒ Habitat mediated predator-

prey encounter rates

Snail Predator Prey/Dynamics Evaluating long-term

dataset of intensive benthic surveys conducted along the Florida Keys

Inform restoration activities by identifying potential areas where this trophodynamic may mitigate coral predation

Photo courtesy of Dirk Peterson

Our vision is to conduct progressively more complex restoration ecology research to guide resource managers in the development of an effective and holistic coral reef restoration strategy

Coral Reef Ecosystem Restoration Ecology Program

Photo courtesy of Jiangang Luo

Questions?