Buổi 62: Reading – T/F/NG + summary: “mốc chuẩn dịch chuyển” trong bảo tồn

Remembering what was lost

(Bài đọc tự viết; vùng biển, nhân vật và ví dụ là giả định.)

A Ask an experienced fisherman in the hypothetical coastal town of Port Elna how the sea has changed, and he may tell you that catches today are smaller than when he started work in the 1980s. Ask his grandfather’s generation, and they might describe fish so large and plentiful that the fisherman’s own “good old days” would seem poor by comparison. Each generation, in other words, tends to measure decline against the conditions it first knew, rather than against a longer history.

B This tendency is often described as the problem of “shifting baselines”. A baseline is the reference point against which change is measured. If each generation accepts the state of nature it encountered in its youth as normal, then gradual losses can go largely unnoticed. Over several generations, an ecosystem may become dramatically poorer while, at any single moment, people perceive only modest change. The idea was first discussed in relation to fisheries but has since been applied to forests, bird populations and many other areas.

C Shifting baselines matter for conservation because targets for restoration depend on them. If planners aim to return a river to the condition it was in thirty years ago, they may set a goal that already represents a heavily degraded system. Conversely, if they choose a baseline from several centuries ago, they may set a target that is impossible to achieve, given changes in climate, land use and human population that cannot be reversed.

D How, then, can people recover a sense of what has been lost? One approach is to use historical records that were never intended as scientific data. Old market records of fish sales, photographs of catches, ships’ logbooks and even restaurant menus can reveal the size and abundance of species in the past. Such sources must be interpreted carefully, since they were produced for other purposes, but taken together they can provide a surprisingly detailed picture.

E Another approach draws on the memories of older residents. In Port Elna, a local museum recorded interviews with retired fishermen about the species they used to catch and where they caught them. Some researchers have been cautious about this kind of anecdotal evidence, since memory is selective. However, when interviews are compared with each other and with written records, consistent patterns can emerge. In Port Elna, several interviewees independently described a type of flatfish that is now rarely seen in the bay, and their accounts matched entries in old market records.

F Not everyone agrees that historical baselines should guide policy. Critics argue that ecosystems are always changing and that there is no single “natural” state to which they should be returned. Some suggest that conservation should focus instead on what ecosystems can do now – providing clean water, preventing floods, supporting wildlife – rather than on recreating the past. Supporters of historical baselines reply that, without knowledge of the past, people cannot even recognise how much has been lost, let alone decide what is worth recovering.

G Perhaps the most important lesson of shifting baselines concerns perception rather than policy. Children who grow up with empty skies and quiet hedgerows may come to see these as normal. Simply making people aware that things were once different can change what they regard as acceptable – and that, in turn, may influence what they are willing to protect.