“The natural landscape is
being subjected to transformation at the hands of man, the last and for us the
most important morphologic factor. By his cultures, he makes use of the natural
forms, in many cases alters them, in some destroys them.” – Carl O. Sauer (1925).
When archaeologists or anthropologists use the term “cultural
landscape”, what we are referring to is the space in which human cultural
groups – past or present – operated, and the relics of cultural practices on
the natural landscape. As the quote from Sauer notes, humans have a
transformative effect on the environment, modifying the natural condition of an
area by their presence. These effects are many and varied, and are visible in
most landscapes across the globe.
We’re all able to identify the impacts of humans on the environment,
particularly when faced with built structures like abandoned buildings, stone sculptures
or arrangements (like Stonehenge or the Moai of Rapa Nui), or earth mounds and ditches.
If you try to think of a place without any evidence of human impact, I’m
willing to bet that you’ll find yourself thinking of somewhere ‘wild’.
Somewhere like the Australian outback, or the Canadian wilderness, or the deepest
parts of the Amazon rainforest. But you might be surprised to find that
cultural landscapes exist in these places too, despite the typical
characterization of human occupants of these regions as small-scale societies
of hunters and gatherers with only limited ecological footprints.
In a paper published last month in BioScience, a Californian/Texan
research team investigated the relationships between aragonitic shell middens
and plant biodiversity in the Baja California Peninsula. These shell middens are
the material remains of the exploitation of marine shellfish from the rocky
headlands and sandy beaches some 3000-5000 years ago (Moore 1999; Vanderplank
et al 2014). This activity is not associated with agriculture – harvesting of
shellfish from tidal and intertidal zones is/was a fairly universal practice
identified among coastal societies – but this research shows the extent to
which the simple activity of collecting (and then discarding) shellfish has
modified the local ecosystems which incorporate these remnant midden complexes.
Example of a shell midden created by Aboriginal Australians (Tasmania).
Shell middens form when individuals discard the shellfish remains,
often creating large mounds that incorporate other waste materials such as
seeds, animal bones and broken tools. In the Baja Peninsula, the high, steady
winter rainfall has leached calcium from the discarded shells over several
thousand years, altering the chemical properties of the soil around the middens.
The authors tested the hypothesis that this altered soil chemistry affected the
plants that grew on and around the midden sites. By assessing the vegetation
growing on the middens on the low-lying floodplain, they were able to identify
stark differences in plant diversity between the naturally saline, sodic soils
of the surrounding floodplain, and the aragonite-laden soils of the middens.
As Vanderplank et al. (2014:208) note: “Deposited during the
Holocene, the shells have been weathered, and new anthropogenic soils have
formed that show unique soil signatures and plant communities.” These new soils
are the indirect result of human activity – certainly the creators of the
middens didn’t intend for these soils to form, and in fact, the soils haven’t
formed in similar sites further inland where rainfall is far lower. But the
result of the collection and mass discard of marine shells by late Holocene
people living in the Baja Peninsula, combined with the steady, winter-wet
climatic conditions, has created a unique environment where plants have been
able to colonise and thrive in areas in which they would not otherwise have
succeeded.
References
Moore, J.D. 1999, ‘Archaeology in the Forgotten Peninsula: Prehistoric Settlement and Subsistence Strategies in Northern Baja California’,
Journal of California and Great Basin
Anthropology, vol. 21(1): 17-44.
Vanderplank, S.E., Mata, S. and Ezcurra, E. 2014, ‘Biodiversity and Archeological Conservation Connected: Aragonite Shell Middens Increase Plant Diversity’, BioScience, vol.
64(3):202-209.
