From Lists to Living Systems
How Ecosystems Grow and Develop
A forest is more than just a collection of trees—it is a dynamic, evolving network of relationships. This is the story of how scientists learned to measure its hidden pulse.
When you look at a thriving coral reef or walk through an old-growth forest, you are witnessing more than just a collection of individual plants and animals. You are seeing a complex, organized system with its own patterns of growth and development. But how does an entire ecosystem mature? And can we actually measure this process? For decades, ecologist Robert E. Ulanowicz has pursued a radical idea: that it is possible to quantify the growth and development of an entire ecosystem. His work, which he termed "ecosystems phenomenology," challenges us to see the living world not as a static picture, but as a dynamic, evolving process 1 .
More Than the Sum of Its Parts: What is Ecosystem Development?
Systems Thinking
Traditional ecology often breaks down nature into its component parts—studying a particular species, tracking a nutrient, or measuring population sizes. Ecosystems phenomenology proposes a different approach. It asks us to consider the system as a whole, focusing on the network of relationships and flows of energy that bind all the elements together 1 .
Ascendency Concept
At its core, this perspective suggests that as ecosystems develop, they don't just get bigger (growth); they also become more organized and coherent (development). Ulanowicz introduced the concept of "ascendency" to capture this dual nature of ecosystem development. Ascendency quantifies both the total amount of energy flowing through a system and the degree to which those flows are organized and efficient 1 6 .
This challenges straight reductionism, the idea that a system can be understood entirely by studying its parts in isolation. Instead, ecosystem development is not entirely determined by events at smaller scales. A developed ecosystem influences its component processes and structures, creating a feedback loop between the whole and its parts 1 .
Ecosystem Development Trajectory
The Philosophical Ground: Eco-Phenomenology
This scientific framework has a deep philosophical cousin known as eco-phenomenology. While Ulanowicz focuses on mathematical models, eco-phenomenology focuses on our lived experience. It argues that our consciousness is not separate from the natural world but is fundamentally intertwined with it 2 .
Eco-phenomenology encourages a shift from merely observing nature to actively experiencing and interacting with it. It challenges the anthropocentric view that humans are the center of existence and that nature's value is only in its utility to us. Instead, it advocates for a relational understanding, where non-human entities—animals, plants, rivers—have their own intrinsic value and agency 2 3 . This philosophical stance aligns with the scientific view of ecosystems as self-organizing networks, providing a more holistic ethical foundation for sustainability.
Key Principles
- Interconnectedness of consciousness and nature
- Relational understanding of ecosystems
- Intrinsic value of non-human entities
- Embodied experience of environment
A Deep Dive into the Past: The North Sea Experiment
How can we possibly measure the development of an ecosystem, especially when human activity has already altered so much of the planet? A groundbreaking study from 2025 provides a brilliant example by turning back the clock 4 .
The Methodology: Building a Digital Time Machine
Historical Baseline (1890s)
The researchers developed a mass-balanced model of the North Sea ecosystem for the 1890s. This period represents the onset of industrial fisheries, just before fishing intensity skyrocketed. The model was built using historical landings data recovered from the 'Fishery Board for Scotland' archives—literally pulling records from "dusty archives" to reconstruct a past state 4 .
Modern Benchmark (1990s)
For comparison, they built a second model with an identical structure for the 1990s. This period was chosen because it is a common reference point for existing ecosystem-based management in the North Sea 4 .
Comparing the Models
Using a suite of ecological indicators, the team compared the structure and function of the two ecosystems. These indicators quantified aspects like energy flow, trophic interactions, and biomass distribution, allowing them to translate complex food web dynamics into comparable metrics 4 .
Results and Analysis: A Century of Decline
The findings were stark. The century of industrial fishing pressure had triggered cascading changes throughout the food web, leading to a clear decline in the ecosystem's maturity and resilience 4 .
| Indicator | 1890s Ecosystem | 1990s Ecosystem | What It Means |
|---|---|---|---|
| Average Trophic Level | Higher | Lower | A shift from large, long-lived predatory fish (like cod) to smaller, short-lived species. |
| Biomass-to-Production Ratio | Higher | Lower | The system moved from maintaining large standing stocks to a faster, less efficient turnover of organisms. |
| Energy Cycling | More complex, internal cycling | Simpler, more linear flow | A loss of the complex, redundant pathways that buffer a system against disturbance. |
| Ecosystem Resilience | Higher | Lower | The modern ecosystem has a reduced capacity to withstand shocks and stresses. |
1890s North Sea
The 1890s North Sea was a more mature and developed system. It had a higher proportion of top predators, more complex internal energy cycles, and a greater capacity to withstand shocks.
1990s North Sea
In contrast, the 1990s ecosystem was simpler, more linear, and less resilient, reflecting what the study called the "industrialization" of the North Sea 4 .
This has a profound implication: much of today's fisheries management is based on an ecosystem structure that is already significantly degraded. The study argues that historical models, representing a "quasi-pristine" state, should be used as baselines for restoration and management targets, helping us understand what these systems are capable of being 4 .
| Tool | Primary Function | Application in the North Sea Study |
|---|---|---|
| Ecopath with Ecosim (EwE) | A modelling software to create a static mass-balanced snapshot of an ecosystem (Ecopath) and simulate changes over time (Ecosim). | Used to build the core mass-balanced models of the North Sea for the 1890s and 1990s. |
| Historical Data Analysis | Reconstructing past environmental conditions using archives, logbooks, and archaeological records. | "Fishery Board for Scotland" landing records were analyzed to estimate fish biomass and catches in the 1890s. |
| Ecosystem Indicators | Quantitative metrics that summarize the status of an ecosystem's structure and function (e.g., Trophic Level, Ascendency). | Indicators like the "Biomass-to-Production Ratio" were used to compare the maturity of the two eras. |
| Network Analysis | A set of algorithms to analyze the pattern of connections and flows in a complex network. | Used to map the flows of energy between different functional groups (e.g., from plankton to small fish to predators). |
North Sea Ecosystem Comparison (1890s vs 1990s)
Seeing the World Through a New Lens
The insights from ecosystems phenomenology and eco-phenomenology are not confined to academic journals. They offer a new way to perceive and interact with the world around us.
Cloud-Connected Ecosystems
Consider the fog-shrouded redwood forests of Northern California. From a phenomenological perspective, the fog is not just weather; it is a vital participant in the ecosystem. It is a "cloud-connected ecosystem," where wind acts as an infrastructure, transporting fog that provides up to a third of the water and nutrients for the giant trees. This intricate connection makes the forest a single, cohesive unit extending from the ocean to the air to the land 8 .
Art as Ecological Expression
Artists have even found ways to make these connections tangible. Fujiko Nakaya's Fog Bridge #72494 in San Francisco is a sculpture that uses hundreds of nozzles to shroud a pedestrian bridge in mist. The artwork coalesces ecological, technological, and embodied modes of sensing. It makes the invisible wind visible, models the local cloud-connected ecosystem, and offers a direct, sensory experience of being within an elemental process. It blurs the line between scientific measurement and lived experience, inviting us to feel our place within these vast networks 8 .
| Aspect | Traditional Reductionist View | Ecosystems Phenomenology View |
|---|---|---|
| Primary Focus | Individual parts (species, genes) | The network of relationships and flows |
| Ecosystem Value | Based on utility to humans (instrumental value) | Has intrinsic value and its own developmental agency |
| Human Role | External observer or master | Embedded participant within the system |
| Sustainability Goal | Maximizing resource output | Maintaining ecosystem health and ascendency |
Conclusion: The Path to a Sustainable Future
The work of Ulanowicz and the insights of eco-phenomenology ultimately converge on a single, crucial point: the natural world is a web of interdependent processes, not a warehouse of inert resources.
By learning to see ecosystems as dynamic, self-organizing wholes, we gain a more accurate and respectful understanding of their functioning.
A New Perspective
This perspective is critically important for forging a truly sustainable future. It moves us away from management strategies that view nature as a set of interchangeable parts and toward an approach that values resilience, complexity, and the inherent potential of living systems to organize and develop.
The next time you stand in a forest or look out at the ocean, remember that you are witnessing a living, developing entity—and that our future depends on our ability to recognize and nurture its intricate, dynamic life.