Exercises: Sustainable resource management

Distinguish between renewable and non-renewable resources by applying them to these three cases: a fishing ground, a riparian forest, and a coal deposit. Explain what condition must be met for a living resource to continue behaving as renewable.

Define overexploitation and give a real example of an overexploited living resource, explaining what signal indicates that exploitation exceeds the resource's capacity for renewal.

Explain what these three tools of sustainable fishing consist of — closed seasons, catch quotas, and minimum size limits — and what biological objective each pursues.

Define natural resource and classify these four as renewable, renewable only if well managed, or non-renewable, justifying your answer: water from a fossil aquifer, timber from a managed forest, oil and wind.

Explain what the renewal capacity of a living resource is and what happens when the extraction rate exceeds it continuously, giving a fishing or forestry example.

Explain what information a fisheries manager needs to set a responsible catch quota (stock size, age at first reproduction, annual recruitment) and what risk the fishery runs if the quota is set using outdated data.

Describe two practices that distinguish organic farming from conventional farming (use of inputs, soil management, pest control) and explain what the USDA Organic label guarantees.

Explain what sustainable forest management is and what labels such as FSC or SFI certify on a piece of furniture or a package of paper, indicating why they should be demanded.

Aquaculture already provides nearly half of the fish consumed worldwide. Analyze two advantages and two environmental impacts of fish farms, and explain whether they can be considered the definitive solution to overfishing.

Deforestation of a forest triggers a chain of effects on climate, soil, and biodiversity. Explain this chain of effects and relate it to the increase in atmospheric $\text{CO}_2$ and the loss of ecosystem services.

A fishing ground is estimated to have a stock of $100\,000\ \text{t}$ of a species, with a natural renewal rate of $8\ \%$ per year. a) Calculate the theoretical maximum sustainable catch. b) Explain what will happen to the stock in the following years if the fleet catches $10\,000\ \text{t}$ per year. c) Indicate two uncertainties of the model that could make that figure unsafe.

Compare a short-rotation eucalyptus plantation intended for paper pulp with a native mixed forest of the same county: timber productivity, hosted biodiversity, fire risk, and ecosystem services. Conclude which criteria should guide new plantations.

The Aral Sea went from being the fourth largest lake in the world to almost disappearing when the rivers that fed it were diverted to irrigate cotton. Reconstruct the chain of decisions and of local ecological, social and climatic effects, and draw a lesson applicable to the management of American rivers such as the Colorado River.

Explain what the "tragedy of the commons" is using an open-access fishing ground, and analyze how three tools try to avoid it: individual quotas, fishing reserves managed by fishermen's associations, and marine reserves.

Distinguish between water stress and drought, and compare two water management philosophies: increasing supply (inter-basin transfers, desalination plants) versus managing demand (irrigation efficiency, reuse, water rates). Indicate one advantage and one limit of each philosophy.

An anchovy fishery is depleted after decades of overfishing. Design a management plan to recover it: closed-season measures, scientific monitoring of stock, enforcement control, and a reopening schedule, justifying each decision using the species' biology.

In an Extremaduran dehesa, livestock farming, hunting, and the conservation of threatened birds coexist. Outline the potential conflict between economics and conservation and propose a management model that makes them compatible, explaining which ecosystem services the dehesa supports.

A district lives off intensive irrigation that is depleting its aquifer. a) Analyze the conflict between current employment and the sustainability of the resource. b) Design an orderly transition (changing crops, modernizing irrigation, reuse, water pricing) that reduces extraction without abandoning the district. c) Discuss who should pay the cost of the transition and why.

Compare three sources of protein for the American diet — capture fisheries, aquaculture, and pulses — in terms of trophic efficiency, ecological footprint, dependence on external resources (feed, fishing grounds), and impacts. Argue which combination would be most sustainable and what changes in consumption it would imply.

A large industrial purse seine tuna company operating in the Indian Ocean has obtained a prestigious blue certification for sustainable fishing to market its canned products in the European Union. However, an independent audit reveals three facts: 1) the fleet uses fish aggregating devices (FADs) that result in 15% accidental bycatch of sea turtles and juvenile sharks; 2) local artisanal cooperatives catch tuna one by one with handlines with virtually no discards, but lack certification because the initial audit costs over 35,000 dollars; and 3) independent observers are only present on 10% of the certified fleet's fishing trips.

1. a) Critically evaluate whether this certification guarantees genuinely ecological exploitation or whether it is a case of greenwashing, justifying your answer with the selectivity and monitoring data.
2. b) Analyze how this voluntary labeling system distorts market competition, penalizing artisanal fisheries with lower environmental impact compared to large industrial fleets.
3. c) Based on this case, refute the argument that "global overfishing can be stopped by relying on individual responsible consumer purchases" and propose two binding public regulation measures that governments should officially impose on all fleets.