(2) Goals of sampling

People sample biodiversity broadly (many different taxa) in all sorts of places for all sorts of reasons.

Most of the All Taxon Biodiversity Inventory (ATBI) projects I know about are in parks and wilderness areas. The aim is to discover the richness of life in such places, which many people see as the future of Nature.

Outside reserves, Nature isn't thought to have much of a chance, what with the gradual worldwide intensification of agriculture, industrial use and residential development. The world outside reserves is believed to be species-poor. The species that live in intensively settled places are thought to be a small, particularly resilient subsample of the world's biota. City A will have much the same species list as nearby City B, and the list will include many cosmopolitan species.

Boring! By contrast, an ATBI in a national park will turn up large numbers of species new to science. Exciting! It's like reading the passenger list for Noah's Ark. These species will be saved (we hope). An ATBI shows us what the world was like before we ruined it: a rich stew of biodiversity.

A completely different attitude guides a BioBlitz. Here the aim is to record as many species as possible in 24 hours, and the target areas, for practical reasons, are in cities, towns or near-urban wastelands. Local residents help with the sampling, and get an appreciation of how much life there can be in a weedy lot.

BioBlitzes typically yield unexpectedly long species lists. Some of the records are for genuine relicts, species persisting in tiny, isolated remnants of their former ranges. Other records are for vagrants which seem to be using the remnants as an archipelago of habitat islands. One island isn't enough for survival, but a group of islands can mean persistence.

A third reason for broadly sampling biodiversity (and I'm nowhere near the end of the list of possible reasons, but I'll stop shortly) is to compare two or more areas in order to test a hypothesis.

The areas might be experiment vs. control, burned vs. unburned, logged vs. unlogged, etc. The sampling might also be in a series of target areas of increasing size, in yet another valiant attempt by ecologists to draw a definitive species-area curve.

Comparison sampling differs from ATBIs and BioBlitzes in that the collections typically aren't thoroughly sorted to species level, and the specimens often don't wind up properly curated in museums and herbaria. Too often they sit neglected on the premises of the university or company that carried out the sampling. After a few years, when no one can remember what the codes mean on the sample labels, the specimens get thrown out during a grand day of tidying.

Salvage sampling is different from the above. It's done in a place which is on the To Be Destroyed list, or on the list of places which are Largely Destroyed And Someone Is Coming Next Week To Finish The Job. It might be a remnant of native grassland on a pastoral property which has just been bought by a cropping company or by plantation foresters. It might be an unappealing patch of scrub on the edge of town, now for sale in a booming real estate market. It might be the last forested ridge in a subtropical landscape under pressure from slash-and-burn cash-croppers.

The aim of salvage sampling is to get into museums, herbaria and genebanks whatever is about to be lost. And there will be loss. Biodiversity varies at all spatial scales. No two places have the same biota, and for many groups of organisms, every place has genetically unique forms. In landscapes largely converted from their pre-human condition, the chances are good that salvage sites will have species found nowhere else.

Finding and documenting these before they disappear is the job of biodiversity salvage.