Restoration of aquatic ecosystems pdf

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Aldo Leopold, father of the "land ethic," once said, "The time has come for science to busy itself with the earth itself. The first step is to reconstruct a sample of what we had to begin with. Restoration of Aquatic Ecosystems outlines a national strategy for aquatic restoration, with practical recommendations, and features case studies of aquatic restoration activities around the country.

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In contrast, the intentional creation of biotic assemblages whose species have been selected to provide services without the aim of achieving a reference ecosystem, are called designer ecosystems [2]. Such marine examples are eco-engineered concrete microhabitats such as rock pools incorporated into marine infrastructure and coastal armoring [49]. These terms highlight the extent of human interventions from setting aside, hands-off to hands-on cultivating and transplanting to creating purpose-built ecosystems.

The focus here has been on how, or to what degree, humans intervene in order to restore degraded ecosystems. However, there is another distinguishing criterion in the modes of restoration: the motivation for restoration, or the why. To illustrate, imagine a situation of transplanting historically abundant species that are challenged to survive in changing environmental conditions, versus the introduction of new species that thrive in present environmental conditions and serve essential functions of historically prevalent species.

Two measurement categories reflect underlying divisions in the motivation of restoration: adopt responsibility on behalf of the ecosystem and its constituent species or primarily serve the interests and needs of people. Anthropocentrism takes the view that people and their needs hold the primary importance and captures an interpretation of the world exclusively through human values and experiences [52,53]. In contrast, biocentrism recognizes the survival rights of other organisms [51].

Eco- centrism evolves further from biocentrism and underscores that the conservation criteria of ecosystem stability and integrity, and that all biota are paramount [54]. In this respect, ecosystem restoration and its permutations are grounded in the assumptions of the role or place of humans within or outside of nature. Dichotomies or spectrums capture on one end, a view of humans outside of nature and on the other side, some philosophies understand humans operating within ecosystems.

Scholarship on conservation has given rise to compositionalism and functionalism, rooted in evolutionary and ecosystem ecology respectively [12,50]. In compositionalism, humans are viewed outside of the system and thus their influence is primarily viewed as pernicious [50]. This frame prioritizes biotic communities in ecosystems and seeks to have all the parts compiled or composed in the system, whereas functionalism emphasizes the maintenance of ecosystem functioning and sees people within these systems [12,50].

Functionalism reflects an anthropocentric orientation because the provision of goods or services represents the primary concern of ecosystem health with less concern for changes in biotic composition as long as ecosystems function in the same fashion.

In contrast, compositionalism prioritizes biodiversity and sees the importance of ecosystems as independent of human needs. Different restoration goals have been shown to affect restoration outcomes and divisions in motivation correlate with different stakeholder groups [55].

Ecological engineering or novel ecosystems are rooted in anthropocentrism, whereas those holding an eco-centric view would be uninterested in restoration efforts that only meet function criteria and do not re-establish species and communities that were historically present. Clewell and Aronson [57] recognize five general rationales or motivations for restoration including the biotic e. Restoration of natural capital and ecosystem service provision represent important pragmatic motivations for restoration [55].

A focus on the return on investment or the question of costs and ecological payoffs [58] also underscore anthropocentric motivations. Studies on the success of ecosystem restoration often report transplant survival or biodiversity [37,59], ecosystem goods and services [60], or a combination of these [8,60,61]. Weinstein [12] suggests management schemes attending to differences in eco-centric and anthropocentric goals and anthropogenic use and impact on estuaries.

These studies and articles demonstrate varied conceptions of restoration emphasized by different success measurements, which in turn are grounded in different values toward nature as elaborated above. The primary question addressed here is why motivations matter in ecosystem restoration. Discourses and frames within environmental policy have political power [27,62,63]. The motivations and frames for why to restore marine ecosystems, or more concretely how the problem of marine degradation is framed and thus interventions prescribed, ought to be considered when analyzing and evaluating marine ecosystem restoration governance.

Along the y-axis, there are gradations of anthropocentric and eco- centric motivations, or essentially the why of restoration. The following section will elaborate on the notion of uncertainty in the science and practice of ecological restoration. Uncertainties and decision-making in marine ecological restoration Nature often responds to human intervention in surprising ways [9,32].

Within natural resource management, the desire to eliminate or minimize uncertainty and surprise has gradually been replaced by acceptance of uncertainty as inherent to complex socio-ecological systems, and therefore unavoidable [30,64,65]. Decisions about and implementation of ecological restoration programs involve different forms of uncertainty which emerge from the plurality of values, assumptions, interpretations and behaviors of the various actors involved in governing restoration [9,30,31,66].

Therefore, analyses should explicitly incorporate uncertainties related to both scientific knowledge and plural actor perspectives in order to facilitate communication about uncertainties and devise strategies to deal with them in restoration governance settings. Uncertainty is characterized as incomplete knowledge when there is not enough data available, accessible, or of sufficient quality to provide reliable knowledge of the system to be managed.

High research costs at sea mean that, for most marine ecosystems, large knowledge gaps exist about their structure, functions, biodiversity, and interactions. Incomplete knowledge implies that collecting more or better data in principle could reduce uncertainty and in turn improve understanding of the system to be managed [69]. Nonetheless, attempts to complete knowledge do not always decrease uncertainty; new discoveries usually reveal new knowledge gaps, which lead to new uncertainties [9,32,64].

Unpredictability refers to the uncertainty that arises due to the complex, dynamic, and non- linear behavior of the system to be managed, be it a natural, technical, or social system.

For instance, the impact of combined environmental stressors on coral reef ecosystems is unpredictable due to the interaction of multiple factors affecting various organisms in complex ways [70].

This complexity is compounded when humans are added to the equation, for example when fisheries and marine recreational activities, as well as restoration efforts take place within the same reef ecosystem. As Brugnach et al. While ecological engineering aims to remove this type of uncertainty by controlling natural processes for the provision of selected services, ecological restoration accepts unpredictability, as the biodiversity and final outcome of restored ecosystems is not entirely predictable over time [43].

In this case uncertainty arises from ambiguity [31,72]. In multi-actor environmental governance settings, multiple knowledge frames shape interpretations of the problem at stake and its solution, which may lead to conflict and impede collective action [30]. In this way, frames are related to discourses. Rigs-to-reefs debates illustrate the different—and often conflicting—knowledge frames through which the problem of decommissioning obsolete oil and gas platforms is interpreted, as well as the solutions offered by different actors [27,74—76].

Although system components—natural, technical, and social—are closely interlinked, it is useful to make an analytical distinction of each component where the identified uncertainty originates [31]. The natural system comprises the ecosystem to be restored, including target species and habitats, abiotic factors such as water quality, and other natural phenomena that could either drive or affect restoration initiatives.

For example, incomplete knowledge about native and non-native species interactions and ambiguity regarding the impact of non-native species fosters debates and influences views on necessary or appropriate intervention [26].

The technical system consists of infrastructures, technologies, and innovations through which people intervene in nature. Interventions such as genetic modification, translocation, and de- extinction made lead to controversies in restoration ecology [21,77].

High levels of all three forms of uncertainty surround such initiatives given their states of development incomplete knowledge , unpredictability of ecological consequences, and likely resistance from society due to ethical concerns.

The social system includes economic, legal, political, cultural, administrative and organizational aspects related to ecological degradation and restoration.

Synthesizing discourses and uncertainties to identify governance challenges As demonstrated in Section 2, ecosystem restoration is a crowded space of interpretations and constructions. Although ecologists and restoration practitioners mention uncertainty as a challenge, seldom do they address the differences among the three types as elucidated in Section 3.

The following section elaborates the four discourses and discusses uncertainties in connection to them. This exercise is not exhaustive, but rather illustrative through hypothetical scenarios grounded in real-world experiences in marine ecosystem restoration. How the uncertainties manifest in the four quadrants of the conceptual model will illuminate various governance considerations of marine ecosystem restoration. Spatial management measures such as NTZs established for fish stock recovery purposes exemplify management rooted in this discourse.

NTZs are designated in the hopes that particular commercially or culturally significant species will regenerate in the absence of extraction. In interventions categorized as Helping Nature support Humans, secondary goals may be articulated, e.

Incomplete knowledge and unpredictability are often invoked in the discussion of the effectiveness of NTZs, especially in light of confounding variables [83,84] and cumulative and interactive impacts in marine ecosystems [85]. Ambiguity regarding the value of closing areas for fishing and where those areas ought to be was also expressed by some in the local fisher cooperative. Some fishers claimed that their fishing practices were sustainable already, and thus they did not perceive NTZs as necessary [81].

Situations of incomplete knowledge of effectiveness, unpredictability of interactive and cumulative impacts, and ambiguity as to the necessity of interventions like NTZs highlight the importance of participatory processes for knowledge production and deliberative governance. In addition, spatial interventions at sea have a special challenge of monitoring and enforcement that should also be considered when establishing new governance arrangement around NTZ establishment.

Once again, spatial tools are relevant, and in this case would likely be MPAs with broader ecosystem-level conservation goals.

Additionally, prohibitions of certain human activities—spatially-bound or otherwise—would likely fall in this quadrant. Prohibitions, for example, which pay special attention to marine mammals or seabirds, or non-commercially relevant species highlight the eco-centric orientation of this discourse.

The suggested prohibition of certain sunscreens due to their chemical effects on particular coral species [89] exemplifies the Putting Nature First discourse. In addition, incomplete knowledge and unpredictability in species adaptations and survival can also challenge restoration initiatives when cumulative effects of climate change and commercial fishing pressure stress marine food webs—e.

Participatory and deliberative governance processes will likely be key to meet such challenges. Governance regimes may also need to determine how to ease the social, economic, and cultural disruptions felt as a result of certain prohibitions, such as considering questions of compensation or dispensation. Such assisted restoration practices contrast the unassisted spatial designations of acceptable and unacceptable actions at sea or prohibitions of certain activities or products, as seen in previous sections.

Notable examples of this discourse are seagrass, mangrove, and coral transplantation. In the case of the Dutch Wadden Sea, the benefits to restoring seagrass are manifold, but the Bringing Nature Back discourse championed by environmentalists centers on the historical presence of seagrass beds and their dependent species assemblages [25]. Again, incomplete knowledge and unpredictability intertwine as to whether interventions will work. For instance, seagrass restoration in the Dutch Wadden Sea exemplifies incomplete knowledge and unpredictability as the natural system may have altered and surpassed certain thresholds.

A key dimension of governance includes the ability to mobilize resources, e. Unpredictable outcomes—put bluntly, the inability to guarantee restoration success commensurate with allocated resources—will challenge marine ecosystem restoration.

High cost of full-scale marine ecosystem restoration in coastal environments [93] and at deep sea [16] are notable barriers. Additionally, with eco- centric motivation the goals or intended benefits will likely be through positive externalities. Positive externalities are often provided through public goods or common-pool resources, which can face issues of payment for goods or services because exclusion is structurally difficult.

Therefore, governance regimes will likely need to consider public or collective means to finance these measures and address free-rider problems.

Bringing Nature Back encapsulates the dominant discourse among restoration ecologists and restoration practitioners, as stated: We should not lose sight that what drives us is a sense of ethics and empathy for the diversity of organisms and ecosystem functions—perhaps ecosystems are valuable for their services but let us not narrow or impoverish our world view to only such concerns, [71]. These authors explicitly attend to eco-centric motivations. Nonetheless, there is also inherent ambiguity in Bringing Nature Back.

The question remains: bringing nature back to what? Environmental historians aptly probe this question and cite a tendency to define restoration goals in pre-settlement terms [27,56,94].

Moreover, biodiversity often sits as the primary goal in such restoration initiatives, with an underlying assumption of the nobility of these practices as demonstrated by [71]. Ecological and geo- engineering fit squarely within this discursive frame. In contrast to Bringing Nature Back, these initiatives often hinge upon the needs of society or maintenance of particular economic interests. In its Sand Engine Delfland project large amounts of the nourished sand will spread along The project contributes to flood protection by compensating for sand loses from erosion processes along the coastline, it creates temporary recreational and natural areas, and it contributes to natural dune formation [96].

In the Building with Nature arrangement, the dominant discourse or narrative is that human interventions and nature are no longer separate, but they are regarded as reinforcing, intertwined entities [97]. Other authors [31,98] conclude that ambiguity is the most significant kind of uncertainty in the Sand Engine project, but that the ambiguities identified regarding recreational safety, drinking water quality, and financial commitment are closely related to the other uncertainties incomplete knowledge and unpredictability.

Furthermore, according to [31,98] ambiguity can emerge when the significance or consequences of either unpredictability or incomplete knowledge are framed by project actors in different ways.

Unpredictability is often at play in Building with Nature as the unforeseen effects arise because people do not fully understand the intricate connections of complex ecosystems. Notably, Bradshaw [36] argued that re-constructing ecosystems and restoration experiments enlighten the field of ecology. The case of proposed iron fertilization to combat ocean acidification elucidates the challenges that arise when moving from theoretical models [99] to unauthorized experimentation—and resultant controversy—at sea see [] for summary.

Both examples also demonstrate the business opportunities emerging from such paradigm with geoengineering firms looking to capitalize, which may signal the coming wave of ecosystem restoration investors and private companies.

Whereas Bringing Nature Back centers on the arising challenges of providing public goods or common-pool resources—both of which have the difficulty to exclude individuals—Building with Nature will often center on protecting the assets of private users e. Once again, the discussion of allocating resources for interventions and the question of who benefits will be central to governance. With high degrees of human intervention will likely come higher costs, making the distinctions among who wins and who loses central in marine ecosystem restoration governance.

The conceptual model presented in this paper provides a means for clarifying the underlying means and motivations of marine restoration. When combined with the three types of uncertainties, particular governance challenges emerge. In cases of lower degrees of intervention, where spatial management and regulation of activity are prevalent, participatory and deliberative processes will be central in determining the extent of the intervention and bolster process and outcome legitimacy [].

In instances of ambiguity, participation may not suffice and thus discussions of the relevance of dispensation or compensation may improve outcomes when monitoring and enforcement are difficult. With higher degrees of human intervention will likely come higher costs. Depending on the structures of the goods and services provided—or the discursive frame of the proposed restoration outcome—public or private financing mechanisms will likely need to be determined. Differences in values, or ambiguity as to the benefits and costs of marine ecosystem restoration will need to be addressed in decision making, with communication holding great importance.

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