Change type and corresponding factors
For pollutants (Figure 2) measurable areas of disturbance
for respective types of change include: algal excess with
high nutrient levels (Dennison and Abal, 1999), center
sinking likely related to a toxicant and/or nutrient (Duke
et al., 2010), species specific with toxic pesticides in runoff (Duke et al., 2005a), and spill damage from toxic and
suffocating petroleum spills (Duke and Watkinson, 2002;
Duke and Burns, 2003; Duke et al., 1997; Duke et al.,
1999; Duke et al., 2000) along with dirty foliage from
excessive dust (Duke et al., 2003).
Pests and pathogens
Predominant drivers
Pests and pathogens are mostly indirect drivers resulting
from the accidental or unintended consequences of human
activities elsewhere. Pests are organisms detrimental to
other more benign biota. They are often exotic and invasive, but this is not always the case. Local biota may also
be pest species. The source of exotic pests includes:
constructed wetlands, aquaculture, aquaria, vessel fouling, ballast water, and dredge spoil. Pest species can
replace native species, cause alteration to habitat, or result
in toxic blooms. Pathogens are bacteria, virus, or fungi
which cause disease in biota, including humans. Some
pathogens occur naturally in marine and estuarine waters.
However, high concentrations of microorganisms are carried downstream in runoff from upstream sources of
human and agricultural waste following storm events. In
addition to catchment runoff and stormwater flows, further potential sources include: aquaculture cultures, exotic
species, imported stock feed, and sewage discharges.
Factor indicators
Changes due to pests and pathogens are influenced by a
number of factors. Herbivore life cycles may also be
influenced by high nutrient content in foliage and additional habitat stressors. Further indicators of pests and
pathogens include: presence and abundance of pest species and pathogens, evidence of harm to native species,
loss of native species, and habitat disruption. Indicators
of pathogens include: presence of pathogens in water,
plant and animal lesions, responses of sensitive species,
disrupted reproductive success, evidence of diseases, and
mass mortality events.
Change type and corresponding factors
For pests and pathogens (Figure 2), measurable areas of
disturbance for respective types of change include: diseased as a result of a pathogen (Fomba and Singh, 1990;
Wesre et al., 1991; Duke, 1997), introduced species
involving invasive biota (Allen, 1998; Allen et al.,
2000), and herbivore attack with an active herbivore
(Johnstone, 1981; Robertson and Duke, 1987; Rau and
Murphy, 1990; Feller and McKee, 1999; Duke, 2002;
Clarke and Kerrigan, 2002).
Climate change
Predominant drivers
Climate change combines both human and natural influences delivered as discrete drivers affecting different types
of change. Mangrove coasts have always existed in a state
of change. Their efficient and effective responses to
altered conditions are the hallmark of their very existence.
The tidal zone where they thrive is constantly changing,
and it has always been a habitat at considerable risk. Over
geological time, for example, inhabitants of the tidal zone
have successfully followed sea-level changes ranging
over tens to hundreds of meters. Therefore, mangrove
coast habitats present today must be appreciated as the survivors of millions of years of adaptation and change. The
component organisms have well-developed and specialized attributes to facilitate their survival in response to natural influences like temperature, rainfall, and sea-level.
The question is: can they cope now with the accelerated
influences of human-induced climate change?
Factor indicators
Changes due to climate change are influenced by a number of factors. Increased air and water temperatures will
allow predominantly cold-restricted mangroves to recruit
and survive in previously inhospitable higher-latitude
locations. Rainfall variability notably affects soil moisture
and salinity conditions to influence species at physiological extremes causing species at key ecotones to die or
recruit. And, finally with sea-level change, as an added
consequence of global warming, the entire tidal zone must
shift upward with mangrove encroachment into upland
habitat and corresponding losses at the waterfront. This
type of change will curiously be similar to the responses
of mangrove coasts to more localized changes in tidal
amplitude, as observed in Southern Moreton Bay in Eastern Australia (Figure 4).
Change type and corresponding factors
For climate change (Figure 2) , measurable areas of disturbance for respective types of change include: latitudinal
shift with temperature change (Gilman et al., 2008; Wilson
and Saintilan, 2012, Williams et al., 2013), ecotone shift
with rainfall variability (Fosberg, 1961, Duke et al.,
2003; Meynecke et al., 2006; Gilman et al., 2008),
and zonal shift with sea-level change (Duke et al., 2002;
Gilman et al., 2008).
Severe natural disturbance
Predominant drivers
The drivers of severe natural disturbance complement and
expand on the influences noted above concerning climate
change. As noted, mangrove coasts have always existed in
a state of change. And, they will continue to do so. Some
changes will also add to these influences, based on arguably natural factors, like wrack buildup as a result of
higher sea waves. The continued influence of severe
storms, is excepted to have worsened with changing
MANGROVE COASTS
419
For pollutants (Figure 2) measurable areas of disturbance
for respective types of change include: algal excess with
high nutrient levels (Dennison and Abal, 1999), center
sinking likely related to a toxicant and/or nutrient (Duke
et al., 2010), species specific with toxic pesticides in runoff (Duke et al., 2005a), and spill damage from toxic and
suffocating petroleum spills (Duke and Watkinson, 2002;
Duke and Burns, 2003; Duke et al., 1997; Duke et al.,
1999; Duke et al., 2000) along with dirty foliage from
excessive dust (Duke et al., 2003).
Pests and pathogens
Predominant drivers
Pests and pathogens are mostly indirect drivers resulting
from the accidental or unintended consequences of human
activities elsewhere. Pests are organisms detrimental to
other more benign biota. They are often exotic and invasive, but this is not always the case. Local biota may also
be pest species. The source of exotic pests includes:
constructed wetlands, aquaculture, aquaria, vessel fouling, ballast water, and dredge spoil. Pest species can
replace native species, cause alteration to habitat, or result
in toxic blooms. Pathogens are bacteria, virus, or fungi
which cause disease in biota, including humans. Some
pathogens occur naturally in marine and estuarine waters.
However, high concentrations of microorganisms are carried downstream in runoff from upstream sources of
human and agricultural waste following storm events. In
addition to catchment runoff and stormwater flows, further potential sources include: aquaculture cultures, exotic
species, imported stock feed, and sewage discharges.
Factor indicators
Changes due to pests and pathogens are influenced by a
number of factors. Herbivore life cycles may also be
influenced by high nutrient content in foliage and additional habitat stressors. Further indicators of pests and
pathogens include: presence and abundance of pest species and pathogens, evidence of harm to native species,
loss of native species, and habitat disruption. Indicators
of pathogens include: presence of pathogens in water,
plant and animal lesions, responses of sensitive species,
disrupted reproductive success, evidence of diseases, and
mass mortality events.
Change type and corresponding factors
For pests and pathogens (Figure 2), measurable areas of
disturbance for respective types of change include: diseased as a result of a pathogen (Fomba and Singh, 1990;
Wesre et al., 1991; Duke, 1997), introduced species
involving invasive biota (Allen, 1998; Allen et al.,
2000), and herbivore attack with an active herbivore
(Johnstone, 1981; Robertson and Duke, 1987; Rau and
Murphy, 1990; Feller and McKee, 1999; Duke, 2002;
Clarke and Kerrigan, 2002).
Climate change
Predominant drivers
Climate change combines both human and natural influences delivered as discrete drivers affecting different types
of change. Mangrove coasts have always existed in a state
of change. Their efficient and effective responses to
altered conditions are the hallmark of their very existence.
The tidal zone where they thrive is constantly changing,
and it has always been a habitat at considerable risk. Over
geological time, for example, inhabitants of the tidal zone
have successfully followed sea-level changes ranging
over tens to hundreds of meters. Therefore, mangrove
coast habitats present today must be appreciated as the survivors of millions of years of adaptation and change. The
component organisms have well-developed and specialized attributes to facilitate their survival in response to natural influences like temperature, rainfall, and sea-level.
The question is: can they cope now with the accelerated
influences of human-induced climate change?
Factor indicators
Changes due to climate change are influenced by a number of factors. Increased air and water temperatures will
allow predominantly cold-restricted mangroves to recruit
and survive in previously inhospitable higher-latitude
locations. Rainfall variability notably affects soil moisture
and salinity conditions to influence species at physiological extremes causing species at key ecotones to die or
recruit. And, finally with sea-level change, as an added
consequence of global warming, the entire tidal zone must
shift upward with mangrove encroachment into upland
habitat and corresponding losses at the waterfront. This
type of change will curiously be similar to the responses
of mangrove coasts to more localized changes in tidal
amplitude, as observed in Southern Moreton Bay in Eastern Australia (Figure 4).
Change type and corresponding factors
For climate change (Figure 2) , measurable areas of disturbance for respective types of change include: latitudinal
shift with temperature change (Gilman et al., 2008; Wilson
and Saintilan, 2012, Williams et al., 2013), ecotone shift
with rainfall variability (Fosberg, 1961, Duke et al.,
2003; Meynecke et al., 2006; Gilman et al., 2008),
and zonal shift with sea-level change (Duke et al., 2002;
Gilman et al., 2008).
Severe natural disturbance
Predominant drivers
The drivers of severe natural disturbance complement and
expand on the influences noted above concerning climate
change. As noted, mangrove coasts have always existed in
a state of change. And, they will continue to do so. Some
changes will also add to these influences, based on arguably natural factors, like wrack buildup as a result of
higher sea waves. The continued influence of severe
storms, is excepted to have worsened with changing
MANGROVE COASTS
419