Michelle Jones
Senior Seminar
September 26, 2007
Article: Coral Reef Disturbance and Resilience in Human-Dominated Environment.
Authors: Magnus Nystrom, Carl Folke, & Fredrick Moberg

Early studies of coral reef ecology were generally limited to reefs in clear waters
from human or continental influences.

Over time views have changed, coral reefs are seen as dynamic systems subject to
natural disturbances.

The ability to recover from them has changed. A major contribution to this change
is human dominance of ecosystems.

Disturbances have ranged from frequent minor pulses, such as grazing and
predation, to large infrequent events, such as peaks of coral predator populations,
hurricanes, sea level and temperature changes.

This set of interacting disturbances, occurring with different magnitude, duration,
frequency and spatial distribution, is referred to as the natural disturbance regime
of coral reefs.

This opens up patches of opportunity for renewal, development of the reef and for
evolution.

Clearing of coastal forests increases terrestrial runoff( sediments and nutrients)
causing indirect and direct effects on algal and coral growth and competition.

Logging can prolong sedimentation, turning a short pulse disturbance into a more
persistent disturbance.

Sedimentation leads to water turbidity, leaving less sunlight for photosynthesis.,
which implies less energy will be available for coral growth, reproduction, and
competition.

There is a difference between human-induced and natural disturbances.

Natural disturbances occur in a pulsed manner. (hurricanes, coral predator
outbreaks)

Human-induced appear in a more persistent manner and slowly accumulate or
occur so frequently there is little time for recovery. (nutrient enrichment,
pollution)

Timing is another factor for disturbances. If reefs are affected during spawning
events, dispersal or settlement of coral larvae, the impact is even greater.

Two definitions of resilience: the stability near an equilibrium state or nonequilibrium environment with multiple stable states.

Water currents are major contributors to resilience because they carry coral and
fish larvae from surrounding areas to damaged reefs.

Concept of ecosystem resilience captures the ability to resist, reorganize, and
reestablish from disturbance, as well as maintaining a diversity of options for
development and evolution.

Pleistocene coral reef records show remarkable persistence in their community
structure for tens to hundreds of thousands of years.

No longer can it be assumed that dispersal and natural variation among local
assemblages in the seascape will buffer perturbations. The capacity to renew,
reorganize and re-establish reefs after disturbance has to be actively managed at
the regional level, involving many sectors in society.

Managing for seascape resilience to increase provides insurance to society in
terms of sustaining a flow of ecosystem services.
This article made me skeptical about the information provided. The authors do agree
that coral reefs are endangered and need some type of management to conserve them.
They provided an abundant amount of information that helped me understand the
how’s and why’s of coral decay. Although, they did not provide me with in depth
information about management and conservation
Michelle Jones
Senior Seminar
September 26, 2007
Article: Confronting the Coral Reef Crisis
Authors: D.R. Bellwood, T.P. Hughes, C. Folke, & M. Nystrom

Goal of coral reef management is to sustain the ability of tropical reefs to
provide the ecosystem goods and services, upon which human welfare
depends.

Coral reefs in serious decline from pollution, over harvesting, disease and
climate change.

The point is to argue that the acceleration of human impacts on reef
ecosystems requires a radical reassessment of the way these important marine
resources are monitored and managed.

Propose that the resilience of reef ecosystems needs to be more directly
assessed and actively managed.

In the absence of human impacts, reefs readily reassemble themselves after
routine disturbances such as tropical hurricanes.

Although, after human disturbances reefs fail to regenerate and instead shift to
an alternate state.

There is little success in predicting regime or phase shifts, because of the
increased instability of coral reef ecosystems before their collapse has often
been unrecognized, even on reefs that are relatively studied.

Resilience is critically dependent on the range of responses to environmental
change by species within each functional group- that is their responsive
diversity.

There are three functional groups that play different and complementary roles
in preconditioning reefs to permit recovery of corals. (bioeroders, scrapers,
and grazers)

Bioeroders, scrapers, and grazers are critical sources to resilience and
vulnerability.

Bioeroder fish remove dead coral, scrapers directly remove algae and
sediment, and grazers remove seaweed reducing coral over growth and
shading by macro-algae.

They key element in resisting phase shifts to degraded alternate states is the
maintenance of successful larval colonization by the full range of coral
functional groups characteristic region.

“No-take” areas (NTA) where fishing and other human activities are
prohibited are an increasingly prevalent approach to coral reef management.

Four major recommendations: 1) The rate of establishment and size of NTA’s,
as a tool for resilience management, needs to be hugely increased. 2) The
focus of NTA’s hotspots must be allowed to detract from the provision of
improved management measures for the vast majority of reefs that are heavily
affected by people. 3) Reef management needs to be more inclusive, proactive
and responsive. 4) Markets for reef resources must be performed to
incorporate economic incentives that prevent exploitation species in critical
functional groups.

Our ability to continue to exploit coral reef resources will depend on an
effective combination of science-based management, public suppot and
political will.
I really enjoyed this article. It was very informational and helped me realize how
much time really affects opinions and studies. Two of the four authors, wrote the
previous article I read. As time went buy there ideas about management and
conservation changed. The article stresses the importance of increasing
management and conservation. Providing recommendations that are logical and
realistic made the article very beneficial for me.