The Other Side of the Tragedy of the Commons: When Underuse Becomes a Tragedy Too

In 1968, ecologist Garrett Hardin published *The Tragedy of the Commons* in *Science*, opening with a simple thought experiment: in a pasture open to all, each rational herder gains the full benefit of adding one more animal while the cost of overgrazing is shared by everyone—so the pasture is destroyed. Hardin's lesson: when a resource belongs to everyone, no one takes responsibility for it, and individual rationality aggregates into collective irrationality (overgrazing, overfishing, pollution).

But Hardin's fable tells only half the story.

The Overlooked Half: Underuse

Growing evidence shows that low use (underuse) or outright abandonment can also degrade ecosystems:

• European grasslands: Centuries of low-intensity grazing maintained unique biodiversity. When farmers left and livestock disappeared, shrubs and forests encroached, and open-grassland species (meadow pipits, certain orchids) vanished.
• Japan's countryside: Aging populations and urbanization have abandoned farmland and forests. Projections suggest large-scale "rewilding" by 2050—which sounds appealing but means biodiversity and ecosystem-service losses for ecosystems that depend on human management.
• Mediterranean olive groves: Generations of low-intensity farming created distinctive cultural landscapes; abandonment erases not only landscapes but traditional knowledge and local species.

Many ecosystems are not "natural" but human-shaped—their health depends on continued intervention.

From Hardin to Ostrom

Hardin later conceded his article should have been titled "The Tragedy of the *Unregulated* Commons." In 2009, Elinor Ostrom became the first woman to win the Nobel Memorial Prize in Economic Sciences, showing that local communities can successfully self-organize to manage commons through clear boundary rules, conflict-resolution mechanisms, proportional responsibilities, monitoring, and participatory decision-making. Yet her work focused on preventing overuse; underuse remained at the margins of scholarship.

A New Theoretical Framework

On April 30, 2026, a paper provided the first systematic framework for the underuse problem:

"Incorporating the underuse problem in the tragedy of the commons" *Authors: Shota Shibasaki, Wakaba Tateishi, Shuhei Fujii, Ryosuke Nakadai* *arXiv: 2604.27520*

Core insight: overuse and underuse are not independent problems but alternative outcomes of the same underlying evolutionary process.

The authors build an eco-evolutionary model coupling individual resource-use strategies with resource dynamics, using adaptive dynamics (a branch of evolutionary game theory). Crucially, it distinguishes two kinds of ecosystem services:

• Provisioning services: direct products (forage, timber, fish)
• Non-provisioning services: indirect functions (carbon storage, water regulation, biodiversity, aesthetics)

Concave vs. Convex: The Geometry of Fate

The evolutionary outcome depends on the shape of the provisioning-benefit curve:

Concave (diminishing marginal returns)

Evolution converges to a unique, continuously stable middle strategy—neither overuse nor underuse—like a well-tuned thermostat.

Convex (increasing marginal returns)

Multiple outcomes become possible: 1. Overuse: resource depletion 2. Underuse: abandonment and lost ecosystem services 3. Bistability: the system settles into either extreme depending on initial conditions 4. Evolutionary branching: the population splits into overusing and underusing subgroups

Strikingly, overuse and underuse are fully symmetric in this framework—different attractors of the same mathematical structure, not moral failures or institutional defects.

Why Is "Not Using" Also a Tragedy?

Many ecosystems have an optimal use intensity below which non-provisioning services decline. For example, moderate grazing on European grasslands prevents shrub encroachment, disperses seeds via trampling and dung, creates microhabitats at varied heights, and sustains grazing-dependent symbioses. When grazing stops entirely, these services disappear—this is not a "return to nature," since Europe's "natural" state is itself the product of millennia of human management.

The Global Underuse Picture

• Aging and rural abandonment: Japan's depopulated farmland and forests predict major ecosystem shifts that are not necessarily beneficial.
• Post-socialist transition: Abandoned collective farms in Eastern Europe led to landscape homogenization, invasive-species spread, and higher fire risk—not ecological paradise.
• Unintended effects of protection policy: Strict "wilderness" reserves that exclude fire and grazing can see native grasses replaced by invasive shrubs, lowering biodiversity.

Policy Implications: Finding the "Goldilocks Zone"

• A single instrument is not enough: Purely restricting use may swing systems from one extreme to the other.
• Valuing non-provisioning services is crucial: The model shows social optima align with evolutionarily stable strategies only when carbon storage, biodiversity, etc., are included—supporting carbon markets, payments for ecosystem services, and tourism-based incentives.
• Adaptive management: Under convexity, bistability and branching mean initial conditions and small perturbations can decide the outcome—early, fine-tuned intervention matters.
• Institutional innovation for moderate use: Following Ostrom, involve local communities—create meaningful rural livelihoods, support semi-natural habitat management, and integrate traditional ecological knowledge.

The Bigger Picture

The underuse side of the commons tragedy reveals a deeper truth: nature and humanity are not opposites. From Amazonian *terra preta* to European semi-natural grasslands, from Aboriginal Australian fire-stick farming to rice-fish systems in Southeast Asia, human fingerprints on Earth are often positive. Conservation does not mean isolation; sustainability does not mean abandonment. The goal is a dynamic, evolving "Goldilocks zone" requiring continuous attention—not a static equilibrium—under a paradigm of humans as part of ecosystems.

Conclusion

Hardin's parable still resonates 58 years on, but it needs a revision:

> Imagine a pasture open to all herders. Each rational herder calculates—but the outcome may be "add one more cow" or "leave for a city job." The former causes overgrazing; the latter lets shrubs swallow the grassland. Both endings are tragedies.

The tragedy of the commons has always been multidimensional: it can be the price of greed, or the price of forgetting.

References

• Shibasaki et al., *Incorporating the underuse problem in the tragedy of the commons*, arXiv:2604.27520 (2026)
• Hardin, *The Tragedy of the Commons*, Science 162, 1243 (1968)
• Ostrom, *Governing the Commons: The Evolution of Institutions for Collective Action*, Cambridge University Press (1990)
• Ostrom, Nobel Prize Lecture, 2009
• Queiroz et al., *Underuse of social-ecological systems: A research agenda for addressing challenges to biocultural diversity*, Land Use Policy 73, 141 (2018)
• Inoue et al., *Simulation of natural capital and ecosystem services in a watershed in Northern Japan focusing on the future underuse of nature*, Sustainability Science 14, 89 (2019)