Can nature heal itself?

Recovery depends on whether the damage is a disturbance or a loss

Question: Can nature heal itself?
Position‹3 of 3: It depends, nature can sometimes heal itself
Argument1 of 2›: Recovery depends on whether the damage is a disturbance or a loss

The argument

Proponents of this position argue that the question is put in a form that cannot be answered, because it treats damage as one thing. Ecosystems evolved in the presence of disturbance. Fire, flood, storm, drought, grazing and disease have shaped them, and the species in them carry adaptations to exactly these events: seeds that persist in the soil for years, roots that resprout after the top is destroyed, fast colonisers specialised in open ground, populations that survive in refuges and spread out again. Damage resembling a familiar disturbance meets a system already equipped to recover from it, and will be recovered from with no help at all. The argument is that novel damage meets no such equipment. Proponents distinguish disturbance from loss: a seed bank survives a fire but not the removal of the soil that held it, a population survives a drought it has met before but not the arrival of a predator or disease it has never encountered, a hillside regrows unless the movement of water through it has been permanently altered, and nothing in an evolved response addresses a persistent contaminant or the extinction of a species the system depended on. On this reading the difference is not one of severity but of kind, between damage the system has a prepared answer to and damage for which it has none. Holders of the view conclude that both of the other answers generalise from a chosen set of examples. Those who say nature heals itself point to abandoned farmland, cleaned rivers and recovering fish stocks, which are disturbances of a familiar type with the pressure lifted. Those who say it cannot point to extinction, altered climate and established introduced species, which are losses of a novel kind. Proponents argue that both sets of examples are accurate, that neither supports a general claim, and that the useful question is which kind of damage a given case presents.

Premises

[P1]Ecosystems evolved under recurring disturbances such as fire, flood, drought and grazing, and species carry adaptations specific to them, including seed banks, resprouting, rapid colonisation and survival in refuges. [P2] Novel damage, including removal of soil, permanently altered movement of water, persistent contamination, newly arrived predators or diseases, and extinction, meets no such evolved response. [P3] The two kinds of damage differ in kind rather than in severity, so examples of each support conclusions only about that kind. [C] Whether nature can heal itself depends on whether the damage is a disturbance the system is adapted to or a loss for which it has no prepared response.

Counter-arguments

Critics argue that the distinction blurs in exactly the cases that matter. Severity converts one kind into the other, since a fire hot enough or frequent enough destroys the seed bank that made fire survivable, which means the categories are not independent of degree after all. They also object that the position purchases its reasonableness by declining to answer, because almost every real case combines familiar disturbance with novel loss, so a framework that sorts cases into two boxes leaves the actual judgement undone. Others note that if the novel category includes the climate then it covers nearly everything, and the position collapses into one of the answers it claims to mediate.

Rejecting the premises

[Rejecting P3] Severity converts disturbance into loss, since a fire hot or frequent enough destroys the seed bank that made fire survivable, so the two kinds are not independent of degree. [Rejecting C] Almost every real case combines familiar disturbance with novel loss, so the conclusion sorts cases into categories without settling the judgement the question asks for.