'%Healthy Reefs for Healthy People - A Guide to Indicators of Reef Health and Social Well-being in the Mesoamerican Reef Region%'%by Melanie McField and Patricia Kramer%

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E C O S Y S T E M FU N C T I O N I N D I C AT O R S

The term ecosystem function generally refers to the many critical processes that control interactions among

ecosystem components -- especially the flows of things like energy (food) and genes.

A consideration of coral reef ecosystem function might include questions like these:

· How many baby corals took up residence on the reef recently?

· How severe is coral bleaching on the reef (or, how many corals have kicked out the partner algae that

feed them)?

· How many bioeroding worms and sponges are living on and in the reef, munching it to bits like

termites?

· How many urchins live on the reef, cropping down the macroalgae that compete with corals?

Many human activities can inadvertently disrupt "flow" processes such as these, but the effects on function

may not be readily visible. Sometimes the first noticeable signs of disruption are cascading effects on structural

components.

For example, it may not be so easy to see the disruptive process of overfishing the plant-eating parrotfishes. But

divers can see visible changes in reef community structure when corals can no longer compete successfully

against the macroalgae that the fished-out parrotfish would have been eating: a rugged, rainbow mosaic of

coral transforms to a monotonous carpet of greenish-brown fuzz.

The fifteen Healthy Reefs for Healthy People Ecosystem Function indicators (F) focus on four key areas to help

monitor reef processes: reproduction and recruitment, coral condition, reef bioerosion and accretion, and

herbivory (Table 7.b).

Table 7.b. Functional Indicators.

Attribute

Indicator #

Indicator

Reproduction &

Coral Recruitment

Recruitment

Fish Recruitment

Coral Size Frequency

Fish Size Frequency

Coral Condition

Coral Mortality

Coral Disease

Coral Bleaching

Reef Accretion &

Coral Growth

Bioerosion

Bioeroders on Coral

F10

Reef Accretion

Herbivory

F11

Herbivorous Fish Abundance

F12

Diadema Abundance

F13

Fleshy Macroalgal Index

F14

Fish Bite Rates

F15

Green Turtle Abundance