Review

Merging paleobiology with conservation biology to guide the future of terrestrial ecosystems

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Science  10 Feb 2017:
Vol. 355, Issue 6325, eaah4787
DOI: 10.1126/science.aah4787

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Looking back to move forward

The current impacts of humanity on nature are rapid and destructive, but species turnover and change have occurred throughout the history of life. Although there is much debate about the best approaches to take in conservation, ultimately, we need to permit or enhance the resilience of natural systems so that they can continue to adapt and function into the future. In a Review, Barnosky et al. argue that the best way to do this is to look back at paleontological history as a way to understand how ecological resilience is maintained, even in the face of change.

Science, this issue p. eaah4787

Structured Abstract

BACKGROUND

The pace and magnitude of human-caused global change has accelerated dramatically over the past 50 years, overwhelming the capacity of many ecosystems and species to maintain themselves as they have under the more stable conditions that prevailed for at least 11,000 years. The next few decades threaten even more rapid transformations because by 2050, the human population is projected to grow by 3 billion while simultaneously increasing per capita consumption. Thus, to avoid losing many species and the crucial aspects of ecosystems that we need—for both our physical and emotional well-being—new conservation paradigms and integration of information from conservation biology, paleobiology, and the Earth sciences are required.

ADVANCES

Rather than attempting to hold ecosystems to an idealized conception of the past, as has been the prevailing conservation paradigm until recently, maintaining vibrant ecosystems for the future now requires new approaches that use both historical and novel conservation landscapes, enhance adaptive capacity for ecosystems and organisms, facilitate connectedness, and manage ecosystems for functional integrity rather than focusing entirely on particular species. Scientific breakthroughs needed to underpin such a paradigm shift are emerging at the intersection of ecology and paleobiology, revealing (i) which species and ecosystems will need human intervention to persist; (ii) how to foster population connectivity that anticipates rapidly changing climate and land use; (iii) functional attributes that characterize ecosystems through thousands to millions of years, irrespective of the species that are involved; and (iv) the range of compositional and functional variation that ecosystems have exhibited over their long histories. Such information is necessary for recognizing which current changes foretell transitions to less robust ecological states and which changes may signal benign ecosystem shifts that will cause no substantial loss of ecosystem function or services.

Conservation success will also increasingly hinge on choosing among different, sometimes mutually exclusive approaches to best achieve three conceptually distinct goals: maximizing biodiversity, maximizing ecosystem services, and preserving wilderness. These goals vary in applicability depending on whether historical or novel ecosystems are the conservation target. Tradeoffs already occur—for example, managing to maximize certain ecosystem services upon which people depend (such as food production on farm or rangelands) versus maintaining healthy populations of vulnerable species (such as wolves, lions, or elephants). In the future, the choices will be starker, likely involving decisions such as which species are candidates for managed relocation and to which areas, and whether certain areas should be off limits for intensive management, even if it means losing some species that now live there. Developing the capacity to make those choices will require conservation in both historical and novel ecosystems and effective collaboration of scientists, governmental officials, nongovernmental organizations, the legal community, and other stakeholders.

OUTLOOK

Conservation efforts are currently in a state of transition, with active debate about the relative importance of preserving historical landscapes with minimal human impact on one end of the ideological spectrum versus manipulating novel ecosystems that result from human activities on the other. Although the two approaches are often presented as dichotomous, in fact they are connected by a continuum of practices, and both are needed. In most landscapes, maximizing conservation success will require more integration of paleobiology and conservation biology because in a rapidly changing world, a long-term perspective (encompassing at least millennia) is necessary to specify and select appropriate conservation targets and plans. Although adding this long-term perspective will be essential to sustain biodiversity and all of the facets of nature that humans need as we continue to rapidly change the world over the next few decades, maximizing the chances of success will also require dealing with the root causes of the conservation crisis: rapid growth of the human population, increasing per capita consumption especially in developed countries, and anthropogenic climate change that is rapidly pushing habitats outside the bounds experienced by today’s species.

Fewer than 900 mountain gorillas are left in the world, and their continued existence depends upon the choices humans make, exemplifying the state of many species and ecosystems.

Can conservation biology save biodiversity and all the aspects of nature that people need and value as 3 billion more of us are added to the planet by 2050, while climate continues to change to states outside the bounds that most of today’s ecosystems have ever experienced?

Photo: E. A. Hadly, at Volcanoes National Park, Rwanda

Abstract

Conservation of species and ecosystems is increasingly difficult because anthropogenic impacts are pervasive and accelerating. Under this rapid global change, maximizing conservation success requires a paradigm shift from maintaining ecosystems in idealized past states toward facilitating their adaptive and functional capacities, even as species ebb and flow individually. Developing effective strategies under this new paradigm will require deeper understanding of the long-term dynamics that govern ecosystem persistence and reconciliation of conflicts among approaches to conserving historical versus novel ecosystems. Integrating emerging information from conservation biology, paleobiology, and the Earth sciences is an important step forward on the path to success. Maintaining nature in all its aspects will also entail immediately addressing the overarching threats of growing human population, overconsumption, pollution, and climate change.

  • Authors after the first seven are listed alphabetically.

  • Present address: La Brea Tar Pits and Museum, 5801 Wilshire Boulevard, Los Angeles, CA 90036, USA.

  • § Present address: Department of Zoology, University of Wisconsin, 430 Lincoln Drive, Madison, WI 53706, USA.

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