SPECIAL ISSUE: INTEGRATING ECOSYSTEMS AND COASTAL ENGINEERING PRACTICE
The Incorporation of Biophysical and Social Components
in Coastal Management
Rodolfo Silva
1
& Valeria Chávez
1
& Tjeerd J. Bouma
2
& Brigitta I. van Tussenbroek
3
& Katie K. Arkema
4,5
&
M. Luisa Martínez
6
& Hocine Oumeraci
7
& Johanna J. Heymans
8,9
& Andrés F. Osorio
10
& Edgar Mendoza
1
&
Malva Mancuso
11
& Milton Asmus
12
& Pedro Pereira
13
Received: 24 September 2018 /Revised: 31 March 2019 /Accepted: 2 April 2019
#
Coastal and Estuarine Research Federation 2019
Abstract
Change is inherent in coastal systems, which are amongst the most dynamic ones on Earth. Increasing anthropogenic pressure on
coastal zones interferes with natural coastal dynamics and can cause ecosystem imbalances that render the zones less stable.
Furthermore, human occupation of coastal zones often requires an uncharacteristic degree of stability for these inherently
dynamic coastal systems. Coastal management teams face multifaceted challenges in protecting, rehabilitating and conserving
coastal systems. Diverse monitoring schemes and modelling tools have been developed to address these challenges. In this
article, we explore various perspectives: the integration of biophysical, ecological and social components; the uncertainties of
diverse data sources; and the development of flexible coastal interventions. We propose general criteria and guidance for an
Ecosystem-based Management (EbM) to coastal management, which aims primarily at adaptation to global change and uncer-
tainties, and to managing and integrating social aspects and biophysical components based on the flows of energy and matter.
Keywords Coastal processes
.
Ecosystem-based adaption
.
Ecosystem-based approach
.
Green infrastructure
.
Ecosystem
dynamics
.
Community-based adaptation
.
Coastal management
Communicated by Kenneth L. Heck
* Valeria Chávez
vchavezc@iingen.unam.mx
1
CEMIE-Océano, Instituto de Ingeniería, Universidad Nacional
Autónoma de México, Ciudad de México, Mexico
2
Department of Estuarine and Delta Systems, Royal Netherlands
Institute for Sea Research and Utrecht University,
Yerseke, The Netherlands
3
Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del
Mar y Limnología, Universidad Nacional Autónoma de México,
Puerto Morelos, Quintana Roo, Mexico
4
Natural Capital Project, Stanford University, Stanford, CA, USA
5
School of Environmental and Forest Sciences, University of
Washington, Seattle, WA, USA
6
Red de Ecología Funcional, Instituto de Ecología, A. C.,
Xalapa, Veracruz, Mexico
7
Leichtweiß-Institut für Wasserbau, Abt. Hydromechanik and
Küsteningenieurwesen, Technische Universität Braunschweig,
Braunschweig, Germany
8
Scottish Association for Marine Science, Scottish Marine Institute,
Oban, UK
9
European Marine Board, Oostende, Belgium
10
Grupo de investigación OCEANICOS, Departamento de
Geociencias y Medio Ambiente, Facultad de Minas, Universidad
Nacional de Colombia, Medellín, Colombia
11
Engineering and Environmental Technology Department, Federal
University of Santa Maria, Frederico Westphalen, RS, Brazil
12
Institute of Oceanography, Federal University of Rio Grande
(FURG), Rio Grande, RS, Brazil
13
Coastal Oceanography Laboratory, Department of Oceanography,
Federal University of Santa Catarina, Florianopolis, SC, Brazil
https://doi.org/10.1007/s12237-019-00559-5
Estuaries and Coasts
(2019) 42:1695
–1708
/Published online:
201921 April
Introduction
Most natural processes in coastal areas are affected by human
interference, particularly by the pressures from urban develop-
ment and agricultural expansion. As the processes and func-
tioning of the ecosystems are altered (Capobianco and Stive
2000) and coasts are transformed, the risks of natural hazards
are increased (Silva et al. 2014) and the lives of the people
living there are impacted. Coastal ecosystems provide numer-
ous benefits to people, including habitat provision, tourism,
scenic beauty, recreation, supporting fishing industries, cli-
mate regulation, regulating through carbon storage, filtering
of coastal waters, sustaining jobs and ocean economies, reduc-
ing risk from flooding and, in some cases, facilitating adaption
to a changing climate (Everard et al. 2010; Barbier et al. 2011).
Given the heightened coastal risks and increasing aware-
ness of the relevance of ecosystems in shaping coastal pro-
cesses and supporting human wellbeing, ecosystem function-
ing must be included today in planning adaptation strategies at
micro- and macro-scales (e.g. land-use policy frameworks,
community engagement) (Moosavi 2017). The implementa-
tion of measures that mimic the functioning of ecosystems
have pro ven valid in some, but not all, cases (Silva et al.
2017). Normally, structural m easures such as submerged
breakwaters, are implemented to regulate hydrosedimentary
flows (Neckles et al. 2002), while non-structural measures
such as sand by-passes across jetties, are intended to maintain
naturally dynamic proce sses and thus restore or mainta in
hydrosedimentary equilibrium (Cooke et al. 2012;
Keshtpoor et al. 2013).
Ecosystem-based Adaptation (EbA) strategies help people
adapt to the adverse effects of climate variability and climate
change by integrating ecosystem services and socio-
econometrics to achieve sustainable exploitation, conservation
and restoration of ecosystems (Colls et al. 2009). The services
provided by ecosystems can be harnessed to increase local
resilience (the capacity of socio-ecological systems to respond
to disturbances and retain the essential structures, processes
and feedbacks) (Martinez et al. 2017) and enhance the adap-
tive capacity of society to increasing risks from natural hazards
(Jones et al. 2012; Reid 2016). EbA approaches have three
main axes. First, it considers ecosystem functioning and con-
tinuous adaptation to dynamic ecosystems rathe r than any
fixed solution; second, it aims to produce flexible plans, rather
than a blue-print for an end-state; and third, it is based on the
continuous acquisition, updating and analysis of information
related to ecosystem changes and interventions. Thus, moni-
toring becomes much more important than in conventional
approaches, as the intervention has no cut-off point in time.
The combination of natural or nature-based features
with structural elements is used increasingly in coastal
management ( Borsje et al. 2011; Temmerman et al.
2013), moving away from traditional engineering towards
hybrid solutions (e.g. Moosavi 2017; Silva et al. 2017).
An example of integrating natural or nature-based features
with structural elements is the innovative BBuilding with
Nature^ programme, which uses a triangle to depict the
relationship between biotic and abiotic environments,
man-made infrastructures and societal governance:
Nature–Engineering–Society (van Slobbe et al. 2013).
The successful use of green infrastructure (e.g. Firth et al.
2014; Ondiviela et al. 2014) involves maintaining the connec-
tivity and dynamics of ecosystems (Gillis et al. 2014), by
mimicking their natural functioning in many cases (e.g.
Silva et al.
2017).
EbA will be more effective if it also includes Community-
based Adaptation (CbA). CbA has a human rights-based ap-
proach to development, targeting the people most affected by
the changes and including them in planning, adaptation and
implementation (Reid 2016). CbA programmes consider a
range of factors, such as disaster risk reduction (DRR), en-
couraging climate-resilient livelihoods and developing locally
adaptive and organisational capacities that address the under-
lying causes of vulnerability. Decision making which inte-
grates EbA and CbA will provide the best outcomes in coastal
management and protection.
Ecosystem-based Management (EbM) is not simply
substituting man-made coastal protection infrastructure with
ecosystems which have similar functions, it involves a reas-
sessment of the physical, ecological and social factors affect-
ing the area to achieve sustainable coastal management.
This paper explores the state of the art of EbA, EbM and
CbA in coastal management and points to some flexible solu-
tions which combine biophysical, ecological and social com-
ponents. It also pr ovides an understanding of EbM in the
context of global changes and uncertainties.
Materials and Methods
Sustainable management of specific coastal and marine sys-
tems involves reviewing their past and assessing current and
future issues, threats and needs (Gilman 2002). If possible,
end-to-end ecosystem models, or coupled models (Heymans
et al. 2018), are favoured as they focus on how the physical
environment and human interference affect coastal ecosys-
tems and point to possible socio-economic consequences
(Serpetti et al. 2017). In the pre-planning stage, physical, eco-
logical and social approaches, which include EbM (EbA and
CbA), should produce a concrete diagnosis for the site
concerned.
The Physical Component
This refers to the acquisition of the minimal, acceptable and
ideal levels of information needed for decision-making, taking
Estuaries and Coasts (2019) 42:1695–1708
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Estuaries and Coasts (2019) 42:1695–1708
into account the relative importance of the effects of wave and
wind climates, nearshore currents, temperature and salinity
gradients, sediment sources and sinks, sediment transport,
geomorphological changes and the effects of changes in rela-
tive sea level (Capobianco and Stive 2000). The physical com-
ponent requires continuous monitoring of the above-
mentioned parameters and of their external driving forces,
which are susceptible to change as a consequence of human
activities.
The physical approach includes exploration of the potential
benefits and consequences of coastal disruption (e.g. defence
structures, beach nourishment) while focusing on mass/energy
fluxe s and ecosystem connectivity. Potential intervention s
may generate windows of opportunity, which foster the estab-
lishment of key species, or contr ibute to the creation of a
physical environment that induces appropriate dynamics to
mimic specific ecosystem functions (Balke et al. 2014;
Martinez et al. 2017).
The Ecological Component
In this approach, the dynamics of the ecosystems must be
sufficiently understood to allow predictions to be made
concerning their responses to changes in the physical environ-
ment. However, this is often complicated by two factors: first-
ly, the dynamics of an ecosystem may be driven by changes in
physical or biological processes in adjacent systems or chang-
es in sediment and nutrient fluxes induced by changes in eco-
system connectivity (Gillis et al. 2014; Guannel et al. 2016).
For example, the long-term dynamics of tidal marshes respond
to the short-term dynamics and shape of the adjacent tidal flat
(Bouma et al. 2016; Cao et al. 2018;Huetal.2015). Secondly,
ecosystems are inherently complex, with internal positive and
negative feedback loops that may cause non-linear responses,
delay or bi-stability (Scheffer et al. 2001; van der Heide et al.
2007; van Wesenbeeck et al. 2008). Thus, responses to en-
vironmental changes may be masked until sudden c ol-
lapse is inevitable. Subsequent recovery of such complex
systems may be inhibited by the absence of positive feed-
back loop s, de sp it e effor ts to re s tore t h e pr evi ou s ab iot ic
conditions (e.g. Heymans and Tomczak 2016;Maxwell
et al. 2017; Tomczak et al. 2013).
Monitoring the impact of changes in the physical environ-
ment on coastal ecosystems may allow us to identify critical
patterns and/or early-warning signals (EWSs) (Rietkerk et al.
2004;Schefferetal.2001; van Belzen et al. 2017). Through
dynamic systems theory (Scheffer et al. 2009), these EWSs
may be detected early enough to allow for measures that mit-
igate and reverse these changes, and/or allow for adaptation to
these changes (Ferrier et al. 2016). However, responding to
EWSs may not be sufficient to avert regime shifts. This may
be due to the lack of resolution in the monitoring data for
systems, which are gradually moving towards a tipping point,
to the inherent stochasticity and non-linearity of the processes
underlying regime shifts, or to difficulties associated with bio-
complexity and knowledge gaps in the field o f pred ictive
ecology. Therefore, since there are considerable uncertainties,
a precautionary principle should be followed (Southgate et al.
2003; Tedsen and Homann 2013).
Ecosystems are affected by the physical environment, but
they also modify the physical env ironme nt. For instance,
coastal ecosystems can attenuate waves, slow water flow, se-
cure sediments and reduce storm surge (Feagin et al. 2015;
Martinez et al. 2016; Silva et al. 2016a, b), while they are also
affected by these conditions. The magnitude and nature of
these effects are very context dependent (Ondiviela et al.
2014; Ruckelshaus et al. 2016). Ecosystems with different
foundation species, such as coral reefs, saltmarshes, man-
groves, dunes and seagrass meadows influence coastal pro-
cesses differently due to variations in their structure, morphol-
ogy, species interactions, recruitment rates, longevity and oth-
er life history characteristics (reviewed in Arkema et al. 2017a
and papers within). The spatial and temporal variations inher-
ent to coastal ecosystems can result in changes such as the
rugosity and height of a reef, reef crest width, density and
structure of vegetation or/and its protective efficiency against
waves and currents. Consequently, gathering site-specific data
on these changes during the diagnostic phase will help scien-
tists and managers to better understand and anticipate the role
of ecosystems in coastal dynamics.
The additional benefits of EbM, such as the optimal uses of
resources and socio-ecological adjustment are included when
adaptive management criteria a re employed (Mee 2 012;
Plummer et al. 2012). Ecosystem modifications implemented
to enhance coastal protection may induce changes in ecosys-
tem patterns and processes and impact environmental and so-
cial conditions (e.g. fisheries, recreation/tourism, carbon stor-
age, water quality).
The Social Component
The dynamic interactions between society and natural ecosys-
tems imply that changing human conditions and activities
necessarily drive changes in ecosystems, which in turn, mod-
ify human well-being (van Slobbe et al. 2013).
EbM should facilitate social participation in coastal man-
agement. But to be adequate and effective, identification of the
following points is necessary: the ecosystem services to be
used or preserved, the social and economic benefits offered
by the services, and the social actors directly involved
(Scherer and Asmus 2016). EbM requires social participation
and should seek out the actors affected by the specific
services/ecosystems and define social groups connected
through ecosystem services. This approach should by-pass
broader social participation models, which are not necessarily
effective in decision-making (Méndez-López et al. 2014).
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However, direct participation of the community in plan-
ning, monitoring and decision-making is essential: by encour-
aging stakeholders to implement measures acceptable to the
community, serious social or economic conflicts are less likely
(Gilman 2002). From the start of a project, the implementation
and assessment of alternative strategies, managing expecta-
tions and projecting the services considered to the community
are vital to promote positive synergies. Including local volun-
teers in some types of preliminary data collection and post
intervention monitoring reduces costs, raises awareness and
fosters the spirit of a community sharing in rescue action.
Other important issues are the monitoring and quantification
of the benefits and costs of each alternative strategy, including
social aspects, such as public well-being and safety.
The Diagnosis Process
An ideal coastal diagnosis is based on data of sufficient quality
and quantity; unfortunately, this is not always available and,
even so, decisions must still be made with the information and
knowledge there is, at the time. A simple framework to guide
multidisciplinary teams in leveraging the information avail-
able and best practices experience is proposed here. First,
the team should first prioritise the information groups (ecolo-
gy, geomorphology, geology, marine climate, socioeconomic
and legislation) according to the amount of attention they re-
quire (see Fig. 1). The type of activities to be promoted on the
coast will determine the priority of the information to be col-
lected. Next, the information available is grouped into the
relevance categories: minimum indispensable, acceptable
and ideal.
Table 1 shows examples of data for each information group
in the three relevance categories. Depending on the problem to
be faced, the information necessary will vary in each category,
and in some cases, decisions will have to be made wi th less
information, especially when acquiring the data requires
long-term monitoring. The examples cited here are
intended to serve as a guide for diagnosis and decision-
making. Other criteria may be neces sary, depending on
the nature of a given project.
An EbM approach shoul d consider different sources of
information that include current knowledge, ecosystem ser-
vices, system dynamics and continuous monitoring (Fig. 2).
Considerations for Management
Ecosystem service approaches and models are increasingly
used by public authorities and the private sector when seeking
to understand how these services influence and are influenced
by the biophysical attributes of the coastal zone (Arkema et al.
2015; Reddy et al. 2015).
While there is a tendency towards considering EbA in plan-
ning, several challenges hamper their practical implementa-
tion. Firstly, there are gaps in the scientific knowledge regard-
ing the protection efficiency of nature-based solutions during
extreme events (Möller et al. 2014) and their long-term stabil-
ity (Ondiviela et al. 2014). From the ecological perspective
particularly, there are diverse unknowns that must be ad-
dressed in research and development before EbA, rather than
the current conventional approach, can be adopted in coastal
management. For example, the impact of coastal ecosystem
biodiversity (considering community structure and composi-
tion) on the provision of ecosystem services still remains
largely unknown. In addition, the necessary quantitative
long-term and large-scale models, including feedbacks and/
or connectivity coastal systems are limited (Gillis et al.
2014; Guannel et al. 2016). Moreover, very few designers
and engineers are familiar with such nature-based models.
Secondly, there are no standardised methods or tools for the
design and safety assessment of ecosystems in a coastal pro-
tection scheme nor are there consistent frameworks for legis-
lation or regulation (Restore America’s Estuaries 2015). A
third challenge is harnessing the support of key stakeholders
for the implementation, funding and sustainability of these
solutions, as they may be unfamiliar with EbA and its
benefits (Olsson et al. 2004; Scyphers et al. 2014;
Scyphers et al. 2015). Finally, EbA requires collaboration
between governmental agencies, NGOs, private sector en-
terprises and academic disciplines, which generally work
in a rather isolated manner.
Fig. 1 Information groups and
relevance categories to help
decision making based on
availability of data
Estuaries and Coasts (2019) 42:1695–1708
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Estuaries and Coasts (2019) 42:1695–1708
Evaluation of ecosystem services is also useful in under-
standing the trade-offs amongst adaptation options and strat-
egies. Four generic strategies in coastal management are con-
sidered: (1) Protect: preserve vulnerable areas, especially cen-
tres of population, economic activities or natural resources, by
using hard structures and/or soft protection measures; (2)
Accommodate or Adapt: if the occupation of sensitive areas
is to persist, a greater degree of flooding caused by changes in
land use should be accepted, construction methods adapted
and preparedness improved; (3) Planned retreat: remove
Table 1 Examples of coastal data that should be considered in EbM
Information
group
Category:
1. Minimum indispensable
2. Acceptable
3. Ideal
Data examples by category
Ecology 1 - Type of coastal ecosystem
- Distribution and spatial extent of different ecosystem types
- Relevant ecosystem characteristics (e.g., density of trunks or shoots, rooting system, rugosity of reef)
2 - Degree of ecosystem conservation
3 - Ecosystem flows (e.g., flows of the founding species, population dynamics of founding and key species,
groundwater and surface water quantity and quality; substrate/sediment quality; connectivity)
Geomorphology 1 - Significant geoforms
2 - Sediment features
- Sedimentary balance
3 - Local morphological evolution
- Forecast of coastal response to projected actions
Geology 1 - Origin and main geological characteristics of the site
2 - Characteristics of sediment mechanics
3 - Analysis of sediment force and resistance
Marine climate 1 - Main coast shaper
- Wave, tide and current regimes
- Wind regimes
2 - Currents induced by waves, tidal currents, long. and cross shore currents, bed shear stress
- Air temperature, humidity, atmospheric pressure
3 - Hydro-meteorological risk assessment
- Prediction of the consequences of extreme and extraordinary events
Socioeconomic 1 - Population data
- Main economic activities
- Land data (e.g., property values, land farmed communally, land use permits)
- Historical or cultural value of the area
2 - Population growth rate
3 - Historical records of vector diseases in the population
- Causes of mortality of flora, fauna and humans
Legislation 1 - Federal maritime terrestrial zone
- Protected natural areas
2 - Protection measures
- Local territorial planning
3 - Federal, state and local normativity for ecological, land use and specific activity
Fig. 2 Aspects to be considered
in Ecosystem-based Management
(EbM)
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