Retrospective science informs regional conservation and land management

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W. Wyatt Oswald, David R. Foster, Bryan N. Shuman, Elizabeth S. Chilton, Dianna L. Doucette, and Deena L. Duranleau

Conservation and land management informed by sound science yield multiple benefits for society, including natural resources, biodiversity, and resilience to global environmental change.  To this end, our research group studies how ecosystems vary through time to better understand the pace, spatial patterns, and drivers of ecological shifts.  The insights that come from looking to the past can then be applied to the management of ecosystems, today and in the future.

In our paper published in Nature Sustainability [1], we synthesized paleo-ecological and archaeological data from many study sites across southern New England, with an interest in understanding the nature of the landscape before and following European arrival.  We focused in particular on the origin of openlands—non-forested habitats, including grasslands, heathlands, shrublands, and early successional vegetation—that support many uncommon plant and animal species in the largely forested landscape.  Analyses of ancient pollen grains and charcoal fragments preserved in lake sediments allowed us to reconstruct past vegetation composition and fire, a disturbance hypothesized to have been used by indigenous people for managing the landscape for agriculture and a diversity of resources.  Reconstructions of climate via lake and ocean sediments and human activity via the regional archaeological record allowed us to assess the relative importance of climate and people as drivers of past ecological change.

Bryan Shuman collecting a sediment core from Green Pond, central Massachusetts. Photo by Wyatt Oswald.

Native American populations peaked at two times during the last several millennia: 5000-3000 years ago, during what archaeologists call the Late Archaic period, and 1500-500 years ago, a period known as the Middle-Late Woodland.  These pre-contact societies were complex, widespread, and large, with populations in the tens of thousands [2].  However, during those times when human populations were high, we found no evidence for forest clearance, elevated use of fire, or widespread agriculture.  Of course, the region’s Native people utilized natural resources: they hunted, fished, foraged, and cultivated some edible plants.  But the evidence suggests they didn’t clear large swaths of forest, with fire or other tools.  Rather, over more than 10,000 years, these highly adaptable people shifted activities seasonally across the landscape, taking advantage of a wide range of resources and exerting limited ecological impacts overall.  The region was dominated by mature forests that experienced repeated shifts in composition in response to modest variations in climate, underscoring their potential to change in the future [3].  Widespread openland vegetation appeared only after the arrival of European colonists.

Old-growth hemlock forest in north-central Massachusetts. Our work at the site shows that hemlocks have prevailed there for 10,000 years. Photo by David Foster.

We can take these results and apply them to addressing the conservation and environmental needs of the region today.  Across the broader New England landscape, we advocate for the maintenance of forests as the predominant land cover, both to emulate natural vegetation and to provide maximum environmental benefits and overall sustainability.  To manage for natural, pre-contact conditions, we should reduce or eliminate direct human disturbance on some large tracts, allowing mature forests to develop and change with natural disturbance processes.  In other parts of the landscape, we can manage forests sustainably for timber and other uses, including biomass for heat, with long rotations to maximize carbon sequestration, water quality, and structurally diverse forest ecosystems [4]

Within the forested landscape, the maintenance of openlands, early successional vegetation, and young forests can be achieved by diversified, organic agriculture including vegetable farms, orchards, and grass-fed meat and dairy that yield healthy food for local communities [5].  These practices parallel the European activities that generated these high biodiversity habitats centuries ago, and that are becoming prevalent again with the revitalization of local agriculture in the region.

Goats grazing on pasture land on Martha’s Vineyard. Photo by David Foster.

References

[1] Oswald, W. W. et al. Conservation implications of limited Native American impacts in pre-contact New England. Nature Sustainability (2020) doi:10.1038/s41893-019-0466-0

[2] Chilton, E. S. in Ancient Complexities: New Perspectives in Pre-Columbian North America (ed Alt, S.) 96-103 (Univ. of Utah Press, 2010).

[3] Shuman, B. N. et al. Predictable hydrological and ecological responses to Holocene North Atlantic variability. Proceedings of the National Academy of Sciences (2019) doi:10.1073/pnas.1814307116

[4] Foster, D. R. et al. Wildlands and Woodlands, Farmlands and Communities: Broadening the Vision for New England (Harvard Forest, 2017).

[5] Donahue, B. et al. A New England Food Vision (Univ. of New Hampshire, 2014).

Go to the profile of Wyatt Oswald

Wyatt Oswald

Professor of Science, Emerson College

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