Radical solution could avoid depletion of natural resources

A radical new approach to managing ecosystems reveals how society’s use of forests, fisheries and other natural resources could be inspired by nature, which creates sustainable ecosystems amid intense species competition for limited resources. It had its origins in my work on Serengeti herbivores and the realisation that the ‘harvesting niche’ of humans exploiting natural resources was equivalent to the ‘ecological niche’ found in natural communities, and that the whole ecological model of niche, community, species diversity and competition could be ported across to human systems of resource-use.

Niche grazing in East Africa
diagram from Vesey-Fitzgerald’s East African Grasslands

Resource competition lies behind many of today’s environmental problems: shrinking forests, disappearing lakes and rivers, collapsed fisheries, overgrazed pastures, eroded soils and declining productivity, together with their aftermath of poverty, conflict and hostilities. The problem is set to intensify this century because the abundance of Earth’s natural resources is declining whilst demand from a developing and expanding human population is growing. Yet curiously the driving influence of competition has been largely absent from theories on natural resource use, including the ecological theory of wildlife harvesting and the approaches of green economics and bioeconomics.

Twin beam trawling damages marine habitats

One negative consequence of resource competition is the emergence of technological ‘arms races’ that lead to environmental degradation. Examples are the drying up of shallow hand-dug wells in arid countries when deeper drilled wells cause water tables to fall, and displacement of otter trawlers by modern twin-beam trawlers in the North Sea which increased the harvest of flatfish but damaged seabed communities.

Another kind of problem arises in the case of competition over weakly-governed resources which predominate over much of the globe. The self-interest of commercial users typically drives a ‘tragedy of the commons’ in which sustainable offtake is sacrificed for short-term gain. However real commons are rarely of the kind described by Garrett Hardin – a uniform pasture shared by a collective herd of cattle (one individual puts on an extra cow and all users pay the cost of its grazing). In the mediaeval commons, there were cowherds, shepherds, goatherds, swineherds, gooseherds, horsemen and so on, each with livestock exploiting a different niche – sheep on hills, cows in valley meadows, horses on floodplains, and pigs in woodlands. It provides the first clue as to how the sustainability of wild animal and plant communities, which is based on the separation of ecological niches, might be mirrored in a managed human system based on the separation of harvesting niches.

Tragedy of the Commons: Left – Hardin-type pasture at risk
Right – niche-partitioned pasture that is protected. Elaborated in Murray 2016

The history of humanity is littered with examples where natural resources and entire ecosystems have failed, from the collapse of ancient forest-dependent civilizations to over-exploited wildlife populations today. In the past, we have have often failed to find sustainable solutions to resource use.

In marked contrast to the human-led catastrophes, ecologists have observed that many wild species thrive in natural communities despite intense competition for limiting resources. The rival species share ecosystems by developing narrow ecological niches, as for example when songbirds share forests by feeding and nesting at distinctive heights in the trees. New research suggests that man’s impact on the environment could be tempered by partitioning natural resources into selected parts and licensing users according to different “harvesting niches”, mimicking the ecological niches of wild species. For example, independent fishing vessels could be licensed with exclusive long-term rights to harvest single demersal fish species by using a combination of traditional practices and improved gear selectivity.

An array of advantages over unselective harvesting leaps out. Foremost of these is a reduction in the ‘arms race’ for harvesting technology that, if left to itself, causes increasingly serious damage as it extracts greater quantities of resource. Just as critical, the partitioned resource offers a robust solution to the ‘tragedy of the commons’. This is because the entire cost of overharvesting is born by the individual user within its partition. The individual therefore faces the full consequences of his or her selfish actions. It is a powerful disincentive to overharvesting.

Discarded catch from unselective North Atlantic trawl
Image: Mike R. Jackson

A third significant advantage of selective harvesting in a partitioned resource is rarely mentioned – it allows for a higher sustainable yield from the ecosystem. Take the current unselective trawling of demersal fish: a quota that is adjusted for the maximum sustainable yield (MSY) of a fast-growing fish species risks overharvesting slow-growth ones, whereas a quota that protects a slow-growing species will harvest most fish at below the MSY. By contrast the partitioned fishery can match the effort of each user to the MSY of each species. This achieves a higher overall sustainable yield from the marine ecosystem.

Yet another favourable outcome of the partitioned ecosystem is that the small users are protected from the competitive dominance of larger ones. They are more likely to persist in the long-term providing local communities with jobs and a rewarding lifestyle opportunity.

Wheat fields of South Moravia
Image: Martin King

Modern agricultural development is eroding the number of harvesting niches in the countryside with potentially far-reaching consequences for society. Medieval guilds and niches of rural life, which still exist in parts of Europe and elsewhere, are lost in the process of modernisation leaving little more in the farmed environment other than machinery operators and intensive rearing sheds.

400 tons of jack mackerel caught by purse seiner
Image: C. Ortiz Rojas>

 

The same process of simplification is taking place in fisheries. It feels so much like normal progress that it passes by without much comment, but I think it exposes a bifurcation point which needs to be thought about by society.

 

 

Following along one branch we soon reach industrialised agriculture and fisheries in niche-poor land and seascapes where people are separated from land and sea, and suffer from  simplified ecosystems and lost biodiversity.

Vertical organic sea-farming
Image by Bren Smith

Agroecosystem approach to farming
(Coeur de Chaman)

 

 

 

 

 

 

The other branch leads to partitioned, niche-rich land and seascapes with more diverse, smaller-scale, user groups and greater connectivity of people with land and sea.

Salmon ladder at Rocky Reach Dam, Washington, USA

Wildlife Crossing, Banff National Park, Canada

 

 

 

 

 

 

 

 

Partitioned ecosystems can protect against biodiversity loss and many other environmental problems whilst assisting in UN Sustainable Development Goals to promote peaceful, prosperous and inclusive societies. In addition to these worthy aims, I would suggest they have value in advancing one important goal not mentioned in the 2030 Agenda: attaining greater niche diversity in work, in the environment and in society.

Reference:
Murray, M.G. (2016). Partitioning ecosystems for sustainability. Ecological Applications, 26: 624–636. [ doi:10.1890/14-1156.1 ].