Here are five surprising facts about coastal erosion, reefs and nature-based solutions that may surprise you. In particular, how much you rely on wildlife conservationWhy is animal conservation important? Animal conservation is important, because animals are the only mechanism to create biodiversity, which is the mechanism that creates a habitable planet for humans. Without animals, the energy from today’s plants (algae, trees, flowers etc) will eventually reach the atmosphere and ocean, much of it as carbon. The quantity of this plant-based waste is so More for your future. In this article we will explore each of these in relation to Melbourne’s Port Phillip Bay. But these principles apply to most coastal systems worldwide.
Port Phillip Bay is 2,000km2 bay and relatively sheltered. Yet the livelihoods and lifestyles of 1.2 million people living along its coast are still threatened by coastal erosion. The solution to this is not what it seems. Over the decades we’ve been sold a bum-deal. Making wiser decisions to protect ourselves is going to require a rethink of how we value nature and conservation. The opportunity is huge and positive, so share this story with as many people as possible.
Facts overview
- Despite being built to protect us, hard-engineered solutions to coastal defence e.g. sea walls, beach replenishment, rock groins etc, are now widely considered to be one of the greatest threatening processes to our coastline.
- The natural processes created by coastal reef ecosystemsHow ecosystems function An ecosystem is a community of lifeforms that interact in such an optimal way that how ecosystems function best, is when all components (including humans and other animals) can persist and live alongside each other for the longest time possible. Ecosystems are fuelled by the energy created by plants (primary producers) that convert the Sun's heat energy More (many of which are in a poor state), however, are capable of absorbing up to 97% of wave energy.
- Recent historic loss of fish life has already had a greater impact on coastal processes than most major environmental issues such as climate warming and nutrientA substance that contains the raw materials for life. At a chemical level, these are contained inside compounds that are absorbed into the body and essential energy-containing molecules are extracted, so that energy can be transformed into other chemical processes that use the energy for living. More pollution. This is because fish are the basis for entire ecosystem structures and function(Of an ecosystem). A subset of ecosystem processes and structures, where the ecosystem does something that provides an ecosystem service of value to people. More. Without fish, we have no functioning reefs, we have no nature-based solutions, and no livelihoods in future.
- There has been an almost 100% extermination of large resident reef fish throughout the Bay’s nearshore reefs, rendering the reefs functionless in terms of coastal protection, water quality and a wide range of other services they provide.
- Your insurance premiums for health, property and business, are already increasing as a result of this loss and the largest reinsurance companies in the world are lobbying governments to put nature-based solutions first, as this is the only way to restore balance.
Once we understand this we can begin to make wise decisions. For example, re-establishing wild fish populations will do more, more quickly and sustainably, than any other approach to coastal erosion. By denying the public a hearing on this matter, we are all denied the possibility of a better future while lining the pockets of firms who engineer poor outcomes.
To achieve all of this requires changing the way we handle decisions about our coastline. It means removing corrupting influences on policy and taking account of public needs as part of the ecosystem.
1. Hard-engineered solutions are high risk
In Australia, eighty-five per cent of the population lives near the coast. Yet the cost of sea defence construction, maintenance and upgrades has been shown to be economically unviable [37]. In summary, any engineered coastal defence is:
- High construction cost;
- High maintenance cost;
- Non-adaptive;
- Destructive to other existing ecological systems; and
- Have unintended consequences through enhancing erosion elsewhere.
“The proliferation of defence works can affect over half of the shoreline in some regions and results in dramatic changes to the coastal environment. Surprisingly little attention has been paid to the ecological consequences of coastal defence.” [41]
Artificial structures for sea defence are mostly built on sandy substrate. This causes ‘varied and severe ecological impacts on coastal habitats’[38]. Overall, coastal engineers have now concluded this. They say ‘hard stabilization structures usually alter the natural environment of the coast, producing negative impacts.’ [40]
2. Natural processes work
It’s been shown that reefs can mitigate up to 97% of wave energy. This study mostly looks at fringing coral reefs but there are still substantial gains to be had from any reef system.
‘[Reefs] can provide comparable wave attenuation benefits to artificial defences such as breakwaters’ but more importantly, can be enhanced cost effectively.[1]
Swiss Re report that ‘Steps to ensure functioning coral reefs globally could lower estimated flood damages for 100-year storm events that would otherwise increase by 91% across the globe.[2]’ Analyses by other re-insurance companies in the Caribbean have shown similar results. That reef restoration is significantly cheaper and always more cost-effective than breakwaters, across all nations.
When we design solutions to coastal defence we tend to look at the ‘1 in 100 year’ events, or similar. But these extreme events outdate the lifespan of most constructed options anyway. Further, they can also be severely damaged / destroyed by them.
The more pertinent issue is the cumulative impact of everyday ongoing erosion. This is where natural processes are far more effective. Why? Because natural processes can have daily benefits without any of the cumulative costs. For example, the significant unintended consequences and damage caused by engineered systems.
However, we can never create nature-based solutions unless we have abundant wildlife.
3. The role of fish in coastal sea defence
There is a substantial and rapidly-growing body of evidence that animals are the main driver for ecosystem structure, function and stability [6-21]. The absence of wildlife hampers or inhibits restoration efforts to adapt to, or build resilienceReferring to an ecosystem’s ability to maintain a steady stable-state. The need to build resilience is entirely anthropocentric and symptomatic of ecosystems that are damaged or declining, leading to loss of ecosystem services on which humans depend. More, through weakened and less certain ecosystem structures [22-28].
This is well-established in term of reef fish [29-31]. One study has found, that even intermediate levels of species loss would greatly reduce plant production, compared to climate warming. Higher levels of extinction had effects rivalling ozone layer loss, ocean acidification and even nutrientEnergy and nutrients are the same thing. Plants capture energy from the Sun and store it in chemicals, via the process of photosynthesis. The excess greenery and waste that plants create, contain chemicals that animals can eat, in order to build their own bodies and reproduce. When a chemical is used this way, we call it a nutrient. As we More pollution [32]. Meaning, decline in species, has already had a greater impact than most of the major environmental issues today. Which also means greater potential for restoration!
In Australia, in particular the southeast, there has been massive decline in reef life. This has severe consequences. A point made in 2022 in paper led by Graham Edgar from the University of Tasmania [33]. The disappearance of large fish, which are particularly important, is blamed on excessive fishing.
This is because marine ecosystems with fewer species are functionally compromised. Those with more species are more likely to have functional redundancy and resilience [3-5]. Edgar et al, place restoration of lost ecosystem structure, a ‘nature-based solution’ as the single greatest need [19].
4. Restoring loss of large resident reef fish
In the nearshore environments of Port Phillip Bay we have diverse reef habitat. These comprise coral reef, kelp reef and Sargassum / Caulerpa reef. However, most of these reefs are in very poor health. There has been an estimated 98-99% of resident reef fish decline in Bayside since the 1950s [34], as evidenced by people like Jon Neville.
By the turn of the century, most resident reef fish were absent from rocky reefs in Port Phillip Bay.
The consequence is imbalance that flows through almost every component of the ecosystem. This includes most critical ecosystem services we need to live. Hammerschlag et al [35] shows that aquatic predators function throughout the system, holding it together, and facilitating almost all the ecosystem services we depend on for our livelihoods.
The fish that would diversify and sustain the resilience of the ecosystem are the larger megafaunaThe largest animals that represent the top of the trophic pyramid. These are the final building blocks in ecosystem structures for maximum entropy production. Megafauna can be measured at any spatial scale. The largest animal that ever lived on Earth is the Blue Whale. In a grassland, spiders could be considered megafauna The term is generally reserved for animals larger More. These are leatherjackets, snapper and wrasse, that can live for decades and grow to tens of kilos in weight. A study in the Bahamas has found that ‘Interactions between reef zone and size class were significant with the greater frequencies of larger individuals (≥21 cm) driving patterns (positive associations) on forereefs’ [36].
Restoring these populations is the single greatest thing we can do!
5. The benefit to your lifestyle and livelihoods
It may come as news to you that these effects are impacting your very lifestyle. You probably don’t notice as increasing cost of living creeps up slowly. Your government is having to spend more to remediate failed hard-engineered infrastructure. These crumble as our natural environment erodes. In turn it affects air and water quality, soil loss etc. Then our insurance premiums start to rise in proportion to losing quality of life.
The world’s largest re-insurer, Swiss Re has identified Australia as the second most fragile in the world for BiodiversityWhat is the definition of biodiversity? When we ask, what is the definition of biodiversity? It depends on what we want to do with it. The term is widely and commonly misused, leading to significant misinterpretation of the importance of how animals function on Earth and why they matter a great deal, to human survival. Here I will try to More and Ecosystem Services (BES)[1]. Their analysis underpins the company’s risk assessment that includes insurance throughout Australia The report:
‘… discusses how addressing BES challenges through simple preservation actions can have significant impacts’
Swiss Re calls for ‘Australia to prepare for ecologically driven disturbances. And to look for opportunities in ecosystem services improvements and restoration’ owing to its fragile nature.
Coastal erosion is among the services identified as important. But moves to create nature-based solutions for coastal systems address a far wider range of consumer threats. These include water quality and general quality of life, all of which have been denied, by conventional engineering approaches.
Overall their conclusion is that the:
‘re/insurance industry relies on functioning economies in which citizens and society can generate valuable assets and activities that are worth protecting’ and is calling for ‘nature-based insurance solutions.’
Conclusion
There is an urgent need for properly-qualified advice relating to nature. The first step is to recognise the critical importance of animals to humanity’s future. In a later article I will talk about how we do this. In Melbourne, the policy is already in place to reverse these problems but it will take time. Before that can happen we need to reduce our dependence on certain voices in industry. We need to start to listen to other ideas and build a better understanding of the opportunity. This is critical to the integrity of all our livelihoods, in particular, people who live on or near the coastline.
[1] A fifth of countries worldwide at risk from ecosystem collapse as biodiversity declines, reveals pioneering Swiss Re index https://www.swissre.com/media/press-release/nr-20200923-biodiversity-and-ecosystems-services.html
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