Kirch PV. 1996. Late Holocene human-induced modifications to a central Polynesian island ecosystem. Anthropology. 93:5296-5300.
Blog Author: Alex Shupinski
Author:
Patrick Kirch
EDUCATION
Ph.D., Yale University, 1975
M. Phil., Yale University, 1973
B.A. (cum laude), University of Pennsylvania, 1971
Punahou Academy (Honolulu), 1968
Prehistory and ethnography of Oceania, ethnoarchaeology and settlement archaeology, prehistoric agricultural systems, cultural ecology and paleoenvironmentalism, ethnobotany and ethnoscience, development of complex societies in Oceania.
Abstract
7,000 years of geomorphological and palynological data during the Holocene for Pacific Island (Cook Island) tracking resource exploitation.
2500-1800 were the most significant years from changes and coincided with the arrival of Polynesian people colonizing the island. These human-induced effects included major forest clearance, increased erosion of volcanic hillsides and alluvial deposition in valley bottoms, significant increases in charcoal influx, extinctions of endemic terrestrial species, and the introduction of exotic species.
Introduction
Humans have influenced the land for a long time, it is not a modern phenomenon.
Perfect ecosystem to study because it is separated from the mainland and has a steady-state equilibra.
Austronesians were a horticultural economy, used marine exploitation, transferred livestock, used fire to clear habitats, used stone, shell, bone, fiber.
Managaia Island, 16-18 million years old along the volcanic chain. Deep stratigraphic record and strong archeological evidence makes the island very useful.
-Includes 5 vegetative zones on the island, few animal species, possibly colonized by 2.5 kyr.
Methods
25 cores used for stratigraphic records.
-archeological evidence was obtained from bones (birds, fish, invertebrates), wood charcoal, plant parts and rock shelters. 14C allowed for radiometric dating, 23 bone samples, 40 charcoal samples. 89 samples total
increases in sio2 and A1203, along with free iron, and a decrease in P205. These trends correlate with the pollen evidence indicating removal of climax forest vegetationfrom the central volcanic cone, erosion of the thin organic soil horizon, and exposure of the deeply weathered laterite. Organic content of cores drops in top levels
-increase in erosion and clay deposition
-1.6 kyr signals the removal of indigenous forest vegetation, increase in fernland. Decrease in diversity. Wood charcoal shows the conversion from native forests to anthropogenic vegetation.
-decrease in bird diversity, introduced invasive species like the Pacific rat, crops
-marine and aquatic changes over 1,000 years: freshwater eels were exploited, decrease in gastropod shell size
Discussion
Before the arrival of humans the island had high levels of biodiversity, a forested landscape with insignificant amounts of natural fires and only slight erosion. Major environmental changes occurring during the early-to-mid Holocene were lake formation and peat deposition over Pleistocene land surfaces in the valley bottoms, resulting from rapid sea level rise. Polynesian arrival precipitated the following interrelated changes
-burning, erosion, population reduction, introduction of invasive and domestic animals, introduction of anthropogenic vegetation
Humans were fully capable of dramatically altering the environment even before industrialism.
Thoughts
I really enjoyed this paper because I appreciate tying in all these environmental aspects to drive home the extent of human impact so early on. I was shocked by the rate of change in such a short period of time even after reading many other papers similar to this. We used the evidence of this paper to argue in a debate about recognizing the Anthropocene against the idea that by 1945 we have not made enough of a stratigraphic impact to be recognized as a new epoch.
I loved reading this paper because in the beginning it gave a quick background history to an Island that I've never heard of, but am now curious to visit one day. The island sounds like it was once beautiful before humans were on it, but it was cool to read what has changed since humans came to the island. Again, its sad to think about how human impact has such a negative impact on the environment. As I was reading the results, I noticed how they were throwing out a lot of species of fauna and even organisms that I never heard of. It was cool for me to look up some of the words, but it kind of made me sad to think about how I would have never known these species existed, and how some of them I will never get to experience because they are extinct.
ReplyDeleteI liked the shift of focus that this paper provided. Much of what we've been reading and discussing has focused on human impacts from the Industrial Revolution or even more recently in the 20th century. It was interesting to see the affect of humans without the use of high levels of emissions that are seen today. We have this idea that prior to the Industrial Revolution there was fewer impacts on the globe that goes hand in hand with early civilizations being almost romanticized. This research indicates that the moment humans started changing the landscape we started irreversible changes on the ecosystems.
ReplyDeleteI was kind of stunned by the detail they were able to get in their avifaunal record. Nearly 800 specimens in such a short period! I would kill to have that in the Miocene, but along with what Devra said. The fact that their record is so good is certainly affected by human tendency to leave their trash everywhere! Even without the emissions, we were littering and wrecking ecosystems.
ReplyDeleteI'm not really familiar with the methods used here, so I had to look up a lot of things to get an idea of methods and results. It's pretty refreshing to see a paper that talks about human impacts but not during Industrial Evolution.
ReplyDeleteHumans cause problems intentionally or no intentionally. We don't know how to stop it. We just have to educate everybody. I looked up this Island from the internet, and it is a pretty nice place. However, it is sad to see the impacts and modification of biota. It is very interesting to see how early of these influences were applied by humans on these remote islands. The method seems fascinating. The word "economically important" is devastating. Nowadays, everything on earth seems economically important and that is a great excuse to extract natural resources.
ReplyDeleteI thought this was an elegant paper and was impressed by how thorough their analysis was (like Willow). I was already familiar with their findings (I've birded New Zealand and the same sequence of events happened there) and was shocked to read that the general opinion is that humans didn't start impacting ecosystems until 1,000 years ago. Is this true, or just the author's opinion? If it is true, it's kind of upsetting. Human activity has had negative impacts for a long time. I thought this was obvious.
ReplyDeleteAlso, the writer in me had to appreciate this sentence: "Preindustrial, nonmetal using horticulturally based human populations were capable of major, irreversible transformations to Pacific island ecosystems."
I liked this paper, they do a good job summarizing huge and disparate data sets. The large impact humans had on this island made me think about the relation between biomass and and area requrements for a population. It seems that 52 km2 is too small for 62 kg mammals. It would be interesting to see if this is a factor influencing the impact of pre-industrial humans on these islands or if the impacts were independent from this.
ReplyDelete