Article early view: https://doi.org/10.1002/fee.70000

When we talk about marine conservation, the conversation often turns to big, inspiring commitments—like protecting 30% of the sea by 2030. But behind those headlines lies a more complex challenge: how do we decide what to measure to make sure we’re actually protecting marine biodiversity in all its forms?
Our latest research set out to explore whether new global biodiversity targets truly reflect the complexity scientists see in the ocean. The good news? International policy is making real progress. The cautionary tale? We need to be careful not to lose sight of the foundations that keep the whole system alive.

In 2022, governments from around the world agreed on the Kunming–Montreal Global Biodiversity Framework (GBF) — the successor to the 2010 Aichi Targets. These targets and goals, to be met by 2030 and 2050 respectively, are meant to guide conservation policy for the next decades.
The GBF is more detailed than its predecessor and, crucially, now covers all six classes of “Essential Biodiversity Variables” (EBVs) — covering all six ensures that no major changes in biodiversity go unnoticed. These range from genetic diversity and species traits to the structure and functioning of ecosystems.

Biodiversity isn’t just about counting species. It’s everything from the genes that make species resilient, to the ways living communities are structured, to the functions ecosystems perform (like carbon storage or storm protection). If we only measure one piece of the puzzle, we risk missing critical changes until it’s too late.
Our study found that the GBF does a far better job than the old Aichi Targets in covering the full spectrum of EBVs, meaning it’s less likely that important dimensions of ocean health will slip through the cracks.

While the GBF has improved, we noticed a trend: a stronger focus on ecosystem-level measures (like overall habitat condition) and a relative decline in attention to foundational measures such as genetic diversity or certain species traits.
Why is this a problem? Because ecosystems function thanks to the living species — and their genetic variety — that make them up. If those foundations are weakened, ecosystem “health” may look fine on the surface while crucial building blocks are disappearing underneath.
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For the GBF’s promise to be realised, countries need to:

• Balance what gets measured — keeping both foundational and ecosystem-level data in the mix.
• Invest in better indicators for overlooked areas like genetic diversity and species traits.
• Strengthen national-level implementation of the GBF targets, they are solid foundations to build on.
• Integrate natural and social sciences so conservation is both ecologically sound and socially fair.

Have you ever wondered how changes in the ocean's biodiversity impact people's lives—not just in terms of food or climate, but in the deeper ways we relate to the marine world? Our recent research set out to explore exactly this question, looking beyond the obvious to examine what marine biodiversity truly means for communities living near the sea.

The article was published in npj Ocean Sustainability:
https://link.springer.com/article/10.1038/s44183-025-00148-z
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When we hear "biodiversity change," we often think of shrinking fish stocks or coral bleaching. But the ocean provides so much more than just food or raw materials. It offers us recreation, inspiration, learning, cultural identity—and even a sense of belonging or stewardship. These connections are often described as "relational values", yet they're essential to our well-being.
Our study, focusing on the Wadden Sea (North Sea coastlines of Germany, Denmark, and the Netherlands) and Algoa Bay (South Africa), surveyed marine biodiversity experts on how changes in different groups of marine life—like birds, fish, and plankton—affect what are known as Nature’s Contributions to People (NCPs). We compared the groups of regulating NCPs (e.g. Oysters regulating the water quality), material NCPs (e.g. Herring contributing to our food) and  non-material NCPs (e.g. Seagulls supporting cultural indentities through their iconic calls).
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​Measuring the "cultural value" of biodiversity is complex, and traditionally, policy and science have used economic or ecological metrics, leaving non-material benefits overlooked. Our work highlights the need to integrate these relational values—with their focus on human-nature relationships—into both research and policy.

How can we make conservation more meaningful and just?

• Engage a range of voices: Conservation should include input from coastal communities, Indigenous groups, and local stakeholders—those who experience ocean changes first-hand.
• Focus on partnership, not just participation: True "knowledge co-production" means building partnerships that respect local values, traditions, and even the right not to participate.
• Embrace diverse knowledge: Social sciences and the arts can reveal the emotional and spiritual importance of nature, guiding more effective and inclusive policies.

Policy brief summarising our two most recent studies 

1. Thresholds and tipping points are tempting but not necessarily suitable concepts to address anthropogenic biodiversity change—an intervention
2. Modeling drivers of biodiversity change emphasizes the need for multivariate assessments and rescaled targeting for management 

Find the full open access study here.

We modelled environmental drivers of long-term biodiversity change for fish, birds, macroinvertebrates, and phytoplankton of the German and Dutch Wadden Sea. Trying to capture the innate complexity of biodiversity change, we modelled four metrics of biodiversity.​

That shade sails (yes, the ones around hotel pools or your neighbour’s patio) can be used to assist coral reef recovery?

Dajka, J‐C, Beasley, V, Gendron, G, Barlow, J, Graham, NAJ. (2021) Weakening macroalgal feedbacks through shading on degraded coral reefs. Aquatic Conserv: Mar Freshw Ecosyst. 2021; 1– 10.

The full paper here. The twitter excerpt here.

First, a quick look into the glass ball: 
Tropical coral reefs are changing. Some researchers suggest that modern tropical reefs could take the shape of habitat mosaics. Each patch of the mosaic are small patch-habitats of different regime types (e.g. coral-, sponge-, or algae-dominated) that coexist next to each other. With proper spatial and compositional management of these mosaics, this could present an opportunity to tropical reef stakeholders to maximise ecosystem function and socioeconomic contributions by reefs. For that to work, the patches need to be well connected and those of a certain type (e.g. coral-dominated) cannot be too far apart from each other. 

Second, the problem: 
Fleshy seaweed (or macroalgae) can seriously compromise the function of tropical reef habitat mosaics because of their ability to rapidly expand and limit patch connectivity. Macroalgae can maintain and increase their dominance so well because of effective self‐reinforcing feedback loops. For example, macroalgae can form dense beds, supressing coral settlement and grazing by herbivores. As you would expect, reduced competition by corals and reduced grazing by herbivores quickly leads to the expansion of the macroalgal beds, closing the loop.

What we did: 
We tried to interrupt these macroalgal feedback loops by breaking open those continuous macroalgal beds. We were hypothesising that this would reintroduce grazing to the opened up areas. So, we used submerged shade sails of two sizes (4 m² and 9 m²) to shade dense macroalgal beds for six weeks and recorded changes to the underlying seabed. We also recorded the grazing rates by herbivorous fishes. 

More good news: turf algal growth (smaller algae that can very quickly colonise open space on reefs) was effectively halted. Small shade sails reduced turf algal growth by 23%, while large sails reduced growth by 82%.

So far so good, but did the grazing pressure return? Three months after removal of the shade sails, algal beds had almost completely regrown. So no, herbivory did not return effectively.

​Although it did not fully achieve the disired outcome, our study is the first to achieve macroalgal reduction via the alteration of the light regime and shows that macroalgal feedback loops can be weakened. While macroalgae regrew in this relatively short‐term experiment, shading may be a viable reef management approach that aims to maximise habitat mosaics on coral reefs, particularly if used in combination with other intervention methods.

We took a detailed look at short-spined urchins (Echinothrix calamaris) and their ability to control macroalgae in the inner Seychelles. We did this in a two-part approach starting with modelling general patterns and followed it up with an experimental manipulation. ​​

Conceptual paper: Missing feedbacks in social-ecological systems (SES) can cause ecological degradation. We uncovered them in the coral reef SES of Jamaica. http://dx.doi.org/10.1002/pan3.10092… in @PaN_BES @annawoodhead16 @AlbertNorstrm @MarajaRiechers @naj_graham @LecReefs @LancsUniLEC
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People use their local ecosystem and there are often signals about how this use affects ecosystem health. Capturing, interpreting, and responding to signals that indicate changes in ecosystems is key for their sustainable management. These signal-response chains are called “feedbacks”. Breaks in signal-response chains, “missing feedbacks”, will allow ecosystem health to degrade until a point when abrupt ecological surprises may occur. ​​

​In our study, we demonstrate how we can uncover missing feedbacks using the red loop-green loop (RL-GL) concept and how we may restore the feedbacks. The RL-GL concept classifies how people depend on their local ecosystems along a spectrum of two fundamentally different dynamics. One end of the spectrum is with weak local ecosystem ties and strong ties with external systems (red loop), the other with strong local ecosystem ties and weak ties with external systems (green loop). Both dynamics are theoretically sustainable – but when either end of the RL-GL spectrum follows unsustainable dynamics, for instance through over-consumption of resources, they are classified as red or green traps. 

We classified the dynamics between Jamaican people and their coral reefs for eight different periods through Jamaican history from first human settlement (roughly the year 600) until now. The dynamics between Jamaican people and reefs have moved between all four RL-GL states: green loop, green trap, red loop, and red trap. Through this, we were able to pinpoint where feedbacks between Jamaican people and reefs were missing and which aspects were responsible for this. 

​One of the main aspects that masked the connection between Jamaican people and reefs appeared to be seafood exports. We therefore proposed that the Jamaican system could attempt to gradually move away from seafood exports and get Jamaica back to more sustainable greenloop dynamics between the people and reefs. 

​Our study is the first to apply the RL-GL concept to a coral reef system and we advocate for its practicality in uncovering missing feedbacks and in gaining an understanding of past, present, and future sustainability that can be of use in other systems.

Check out this excellent Leuphana SES blog post and interview with People and Nature about our paper.

​What’s your paper about?

Our paper is about measuring bottom-up and top-down drivers of the ecosystem process of herbivory on coral reefs across large spatial scales. We show how fishing pressure (top-down) and reef condition (bottom-up) influence the rates at which two major herbivorous fish groups graze on algae. We also show how grazing rates are influenced by both the biomass and size structure of grazer assemblages.
Our team conducted this research using underwater survey data from four Indo-Pacific Island regions (Great Barrier Reef, Chagos, Maldives, Seychelles) that are fished with varying intensity and express different reef conditions. These datasets were integrated with herbivore feeding observations from 72 coral reefs to estimate grazing rates.
The paper was also a trial of open science research concepts – we used this paper to learn reproducible tools collaboratively, through GitHub. We even created a fully reproducible manuscript file – download this R-Markdown file to read the data, fit statistical models, and create the full manuscript with figures.

What is the background behind your paper?

​Herbivory helps corals in retaining their dominance on coral reefs by grazing on one of their main competitors – algae. We have gained a solid understanding of how the biomass of grazing reef fish performing this function varies on large spatial and temporal scales, but lack this understanding for large scale bottom-up and top-down controls on herbivory.

What are the key messages of your article?

Our analysis shows that the herbivory function of croppers (e.g. surgeonfish), which control turf algae, was primarily driven by the bottom-up driver reef condition. Cropping rates were highest on structurally complex reefs with few fleshy macroalgae that typically make the substrate inaccessible. Substrate availability and structural complexity also influenced the herbivory function of scraping fish (which promote coral settlement by clearing substrate) but their primary driver was fishing. Scraping rates were least depleted on remote reefs and unfished reefs. Scrapers, i.e. parrotfish, were most influenced by top-down drivers.
The bottom-up and top-down processes affected the grazers most strongly via their biomass. We were able to show that many small-bodied fishes are more likely to exert more grazing pressure than few large-bodied fish. 
Our findings suggest that disturbances that clear substrate for turf algae will likely increase cropping rates in both fished and protected areas, while showing that scraping functions are already impaired on reefs close to human influence, particularly where structural complexity has collapsed. Restoration of this key herbivory function will require scraper biomass to be rebuilt towards wilderness levels.

How did you come up with the idea for it?

James emailed us (a handful of PhD students at Lancaster Environment Centre, UK) last year with his idea to teach us open science tools such as GitHub, and science communication tools such as R-Markdown while working on a short collaborative paper. This way, we could learn how to use tools that would make our science more transparent, learn to work and write collaboratively, and produce a meaningful publication from it. James suggested we could look at variations in grazing functions on coral reefs and what drives them on a large scale. We were lucky that Nick Graham, our supervisor, provided a large dataset covering different geographic regions that he had collected throughout his career. This was a good opportunity to look at what drives herbivory rates at macro-ecological scales.
We thought it was a great idea and were humbled that James would spend his time teaching us these valuable tools to make our science more transparent. We got cracking, learned a tonne, and have been sharing our scripts for publications on GitHub since then. Awesome experience – thanks James!

About the research
What is the broader impact of your paper?

Our study highlights the role that integrating data from multiple locations can play in answering substantial, large-scale, collaborative questions. The open-source nature that laid the foundation to our approach allows a reproducibility that can be used when analysing drivers of other vital coral reef ecosystem functions. You can find our project notes, datasets, data exploration, and scripts at our GitHub repository ‘Grazing gradients’. The (clean and easy to read) supplemental data and scripts accompanying our study are at https://github.com/jpwrobinson/grazing-grads.

Our study is amongst a few other recent studies that begin to answer the question of which large-scale factors drive vital processes on coral reefs. Answers to these questions can accelerate the translation from in-field data to management decisions. We began to answer this question for the process of herbivory, specifically for two major herbivorous fish groups, croppers and scrapers. Forming large-scale hypotheses that span across multiple geographic locations required us to integrate multiple reef condition datasets from four Indo-Pacific regions with grazing rates from 72 reefs. This meant we had the opportunity to work with researchers across the globe.

What is the next step in this field going to be?

Marine communities are changing in response to climate change; therefore, large-scale predictions on how ecosystem functions will perform in the future are very valuable. We hope more studies use similar approaches to ours to answer other large-scale questions. An important cornerstone for this approach is the availability of data from multiple geographical sources. Earlier this year, I learnt about how this cornerstone could be consistently provided by a collaboration between the Wildlife Conservation Society, the World Wildlife Fund and Sparkgeo called Marine Ecological Research Management AID (MERMAID, https://datamermaid.org/). This data platform coordinates the collation of data from various sources and accelerate scientific collaboration. If that is not promising enough, it is also open source (https://github.com/data-mermaid).

About the Author
What is your current position and what are you currently working on?

I am about six months away from finishing my PhD in which I research feedback processes. Basically, cause-and-effect loops on degraded coral reefs. In my PhD, I look at these feedback processes through predictive (1), applied (2), and conceptual lens (3).
First, I focussed on uncovering drivers of juvenile coral density following mass bleaching in the Seychelles. I found which abiotic and biotic drivers were most likely to support and oppose the re-establishing of coral-dominant feedbacks following the 2016 mass bleaching event.
Second, I moved onto weakening macroalgal-reinforcing feedbacks by novel methods of artificial shading and focussed sea urchin grazing. Once weakened, I studied whether the algal-weakening and coral-reinforcing process of herbivory could be reinstated into the manipulated areas.
Third, I conceptually integrated feedbacks with two other frameworks to work from historical social-ecological dynamics between Jamaicans and their coral reefs to fostering future reef sustainability.
What is the best thing about being an ecologist?I think the combination of various job traits (had to mention traits for Functional Ecology) that being an ecologist brings is unparalleled. You get to think deeply about all the nooks and crannies of natural systems, travel and collaborate with other researchers and solve small hands-on problems on fieldwork. You get to code mathematical models that might explain those nooks and crannies a little bit better, plus write and talk about all of it to your colleagues, students, the public, future funders and many more. On top of all that, you have a lot of freedom to structure and approach your day in a way that works best for you. In addition, the best part: knowing there are more traits to discover. It never gets boring.
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You can read the paper in full here and the free plain language summary here. For more on coral reefs, please check out our recent special feature Coral Reef Functional Ecology in the Anthropocene.