Only one in six papers tackles inhabited areas.
The world's top ecologists are failing to study the landscapes that most need work, and they risk delaying conservation efforts and making their subject irrelevant.
That is the stark message from US researchers who have quantified the extent to which ecologists devote themselves to pristine wilderness at the expense of inhabited regions. The bias is a major problem for both the field and the environment, they say, because it is areas used by humans — which take up most of the Earth's land-mass — that are in most need of conservation.
The researchers will present their work at next month's Ecological Society of America meeting in Pittsburgh, Pennsylvania.
"Right now our backyards are black boxes," says Laura Martin, an ecology graduate student at Cornell University in Ithaca, New York, who was inspired to pursue the analysis after she read a feature published in Nature last year (see 'Ecology: Ragamuffin Earth'). "There are suburbs, villages and agricultural lands that are being completely left out of the picture as far as ecological processes go," she says. The tendency to gravitate towards the wilderness for fieldwork has long been recognized among ecologists, but has never before been quantified.
Martin and her colleagues reviewed each of the 8,040 papers that had been published in the top ten ecology journals worldwide over the last five years, homing in on the 2,573 studies that were conducted on land and categorizing them according to the authors' descriptions of the sites examined.
They found that in only around one in six papers had the ecologists deliberately set out to study regions used by humans. Of the 2,573 papers, 323 (13%) were described as having taken place in food-production areas; 78 (3%) in urban areas; and 23 (1%) in suburban areas. By contrast, nearly two-thirds of the studies — 1,629, or 64% — were described as having occurred in "protected areas" such as national or state parks, in which people neither lived nor worked. The remaining 520 (20%) could not be clearly classified, but did not mention human-used zones.
"Approximately 75% of the ice-free terrestrial world is under direct or indirect human use, yet between 63 and 83% of studies are being done in areas without people," says Martin. "The underlying assumption is that human action in an area makes it less valuable to study."
The team also looked at the categories of ecosystem, or biomes, in which the 1,478 studies that gave geographical coordinates had taken place. Temperate-forest biomes such as those in Europe and North America — known for being ecologically productive and moderately biodiverse — were the most over-studied relative to their occurrence around the globe. Deserts were the most under-studied.
They also analysed which category of human ecosystem, or anthrome (anthropogenic biome), the studies fell into. The results seemed to defy the initial finding that ecologists are addicted to wilderness: areas with dense settlements were over-studied by a factor of ten relative to their global area.
"At first we thought the spatial analysis must be wrong," says Erle Ellis, a landscape ecologist from the University of Maryland, Baltimore County, who undertook the global mapping exercise. In fact, he explains, it is a combination of the anthromes that he determined the sites fell within and the authors' field-site descriptions that provides the truest picture of ecologists' behaviour.
A significant portion of studies claiming to be in "protected" areas were actually carried out in highly populated places, but ecologists were conducting their studies in the least-disturbed areas within them — and then studying them as if they were undisturbed by humans. They were not studying the suburban yards or even the parks but the "pretend wild places" around them such as forest reserves, says Ellis. "They are studying them without considering human factors as relevant, and in so doing they are missing the most important aspects of contemporary ecological patterns — process and change."
Walk on the mild side
The message for the field is clear, says Ellis. Although many ecologists have started to recognize the importance of studying peopled landscapes over the past decade or two, they are yet to "walk the talk".
The analysis of anthromes also found that true wildlands — the areas really devoid of humans — were under-studied, receiving 30% less attention than would be expected from their global area. Ellis' take is that ecologists are trying to go to the really wild places but are ultimately falling short. It explains why, he says, the semi-natural anthrome, which is mostly wild but is easier to get to than wilderness, is studied twice as much as its global area would warrant.
Terry Chapin, the incoming president of the Ecological Society of America, says that it is important for the discipline that the bias towards studying the wild is now being quantified. "It is really important that ecologists do research on areas populated by people," he told Nature. "I would hate to go so far as to say studies of pristine areas are not important, but we clearly need to know much more about the direct ways in which we are affecting the biosphere."
Simon Lewis, a researcher from Leeds who studies the ecology of tropical forest, said avoiding direct human impacts was a common strategy in ecology studies because it helped make complex systems more analytically tractable. "Our understanding of even the basic characteristics of major areas, like the Congo Basin, are missing. Adding direct human impacts to studies requires a certain initial understanding first." But he agrees there needed to be some re-balancing of effort both away from pristine habitats — and away from the temperate-zone where most ecologists and their funding originates. "This temperate-zone bias is, I think, is the really fundamental bias in ecological research."
Chapin says that ESA is trying to engage its membership in re-orientating towards issues of large scale ecological and environmental changes taking place, and ecologists should feel challenged to think about their focus. "This study is exactly the sort of thing that needs to be done," he says.
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Biological Invasions (2017)
Biology & Philosophy (2017)