Prehistoric Human Impacts to Marine Mollusks and Intertidal Ecosystems in the Pacific Islands (original) (raw)
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Http Dx Doi Org 10 2984 1534 618861 325 Hiotne 2 0 Co 2, 2007
Archaeology provides a long-term framework to document prehistoric resource use and habitat modification. Excavation at Nu'alolo Kai, Kaua'i, yielded a large, well-preserved shellfish assemblage. Analysis determined the susceptibility of mollusk communities to human foraging pressures in the past. Some coral reef and intertidal species, such as Turbo sandwicensis and Strombus maculatus, declined in abundance as a result of heavy exploitation. In contrast, shoreline mollusk communities remained fairly stable through time. Archaeological research provides baselines for modern conservation efforts and fisheries management.
Human Impacts on the Nearshore Environment: An Archaeological Case Study from Kauai Hawaiian Islands
Archaeology provides a long-term term framework to document prehistoric resource use and habitat modification. Excavation at Nu'alolo Kai, Kauai yielded a large well preserved shellfish assemblage.Analysis determined the suceptibility of mollusk communities to foraging pressures in the past. Some coral reef and intertidal species, such as Turbo sandwicensis and Strombus maculatus, declined in abundance as a result of heavy exploitation. In contrast, shoreline mollusk communities remained fairly stable through time. Archaeological research provides baselines for modern conservation efforts and fisheries management.
Anthropogenic Impacts to Coral Reefs in Palau, Western Micronesia During the Late Holocene
The Palauan archipelago contains one of the most ecologically diverse coral reef systems in the Indo-Pacific that was as attractive for humans prehistorically as it is today. New evidence is emerging that during the past few thousand years there has been increasing exploitation of coral reef resources, particularly finfish and mollusks, leading to a decline in taxa numbers, richness, and diversity in various locales. This paper examines the historical interactions between human populations and coral reef ecologies in Palau by combining known archaeological data and results from modern biological data of different reef fauna. The integration of these data sources provides a framework for attempting to explain variations in taxa composition between islands in the archipelago and how this may relate to human exploitation or other phenomena through time. By using this perspective to link past events with present-day conditions, we can gain a better sense of the extent to which anthropogenic changes may have affected island environments in western Micronesia during the Late Holocene. The study also illustrates the many diffculties researchers face in attempting to synthesize and explain past and present human predation behavior when using disparate sources of data.
The roles and impacts of human hunter-gatherers in North Pacific marine food webs OPEN
There is a nearly 10,000-year history of human presence in the western Gulf of Alaska, but little understanding of how human foragers integrated into and impacted ecosystems through their roles as hunter-gatherers. We present two highly resolved intertidal and nearshore food webs for the Sanak Archipelago in the eastern Aleutian Islands and use them to compare trophic roles of prehistoric humans to other species. We find that the native Aleut people played distinctive roles as super-generalist and highly-omnivorous consumers closely connected to other species. Although the human population was positioned to have strong effects, arrival and presence of Aleut people in the Sanak Archipelago does not appear associated with long-term extinctions. We simulated food web dynamics to explore to what degree introducing a species with trophic roles like those of an Aleut forager, and allowing for variable strong feeding to reflect use of hunting technology, is likely to trigger extinctions. Potential extinctions decreased when an invading omnivorous super-generalist consumer focused strong feeding on decreasing fractions of its possible resources. This study presents the first assessment of the structural roles of humans as consumers within complex ecological networks, and potential impacts of those roles and feeding behavior on associated extinctions. Most studies of the relationships of humans and ecosystems are presented in terms of human impacts on ecosystems 1,2. However, our ability to understand and mitigate human impacts depends on research that elucidates the roles humans play in ecosystems including how they interact with other species 3. In modern marine ecosystems, humans are depleting many commercial fisheries, causing major disruptions to ecosystem function and the persistence of species 1,4–7. As a result, regulators have curtailed fisheries and excluded local peoples from traditional harvesting territories 2. This is a critical problem for the Aleut peoples of the western Gulf of Alaska, who depend strongly on biotic resources from the marine communities 8–10. This central dependence on marine resources stretches back throughout the nearly 10,000-year prehistory of human presence in the North Pacific, raising the questions of what kinds of impacts humans have had on marine species and ecosystems in this area and how should future impacts be managed. In general, the specific roles that local, prehistoric peoples have played in the structure and functioning of marine ecosystems are poorly documented and largely unknown or necessarily somewhat speculative. Unlike in many terrestrial systems, where there is increasing evidence that prehistoric humans likely contributed directly and indirectly to the extinction of a number of species, there is little evidence for such extinctions in marine systems 11. This does not mean that prehistoric humans had no significant impacts on marine ecosystems. For example, in the Aleutian Islands, there is evidence that through hunting of sea otters, prehistoric humans may have caused certain areas to switch from algal-dominated kelp-forest habitats into sea-urchin-dominated barrens devoid of macroalgae 12 , a well-documented trophic cascade. This in turn could have limited the habitat and population of Steller's sea cows, which also were probably hunted or scavenged occasionally by prehistoric
Historical Reconstruction Reveals Recovery in Hawaiian Coral Reefs
PloS one, 2011
Coral reef ecosystems are declining worldwide, yet regional differences in the trajectories, timing and extent of degradation highlight the need for in-depth regional case studies to understand the factors that contribute to either ecosystem sustainability or decline. We reconstructed social-ecological interactions in Hawaiian coral reef environments over 700 years using detailed datasets on ecological conditions, proximate anthropogenic stressor regimes and social change. Here we report previously undetected recovery periods in Hawaiian coral reefs, including a historical recovery in the MHI (,AD 1400-1820) and an ongoing recovery in the NWHI (,AD 1950. These recovery periods appear to be attributed to a complex set of changes in underlying social systems, which served to release reefs from direct anthropogenic stressor regimes. Recovery at the ecosystem level is associated with reductions in stressors over long time periods (decades+) and large spatial scales (.10 3 km 2 ). Our results challenge conventional assumptions and reported findings that human impacts to ecosystems are cumulative and lead only to long-term trajectories of environmental decline. In contrast, recovery periods reveal that human societies have interacted sustainably with coral reef environments over long time periods, and that degraded ecosystems may still retain the adaptive capacity and resilience to recover from human impacts.
Building up the Historical Perspective of Human-Mollusk Interaction
Paper presented at the 33rd Conference of the Association of Marine Laboratories of the Caribbean (AMLC), St. Thomas, US Virgin Islands, June 4-8, 2007., 2007
The exploitation of marine mollusks impacts both human societies and the environment. Although mollusks have been quite resilient to human exploitation, overfishing of shellfish is one of the major disturbances that humans provoked in world coastal ecosystems. The specific nature and dynamics of this disturbance have yet to be determined by historical research of long-term ecological changes. On the other hand, although modernization impacts and changes traditional village lifestyles of many peoples living in coastal zones and islands, molluscan resources continue to be a major staple diet and a source of income of many communities around the world. Whilst the impacts of the marine mollusks on human societies have been widely researched, little attention has been paid to the early human impact on marine mollusks’ populations. In consequence, our current understanding of the ecology, biomass, resilience, and population dynamics of marine mollusks harvested before recent times (19th – 20th century) is relatively poor. We argue that sustained efforts of interdisciplinary teams that may fully address mollusk exploitation in a historical perspective will allow formulating new hypotheses, generating explanatory models, and provide independent means to test and assess generalizations about the status of natural populations of mollusks before, during and after the long standing prehistoric harvesting.
Giovas et al_Mollusk impacts_JAS 2011
Past research has suggested that the humped conch (Strombus gibberulus), a species common in many prehistoric archaeological sites in the Pacific, declines in size and/or abundance over time. Explanations for this phenomenon largely revolve around the possibility that they were overharvested by human populations. In this study, we measured the length and width of over 1400 individual specimens of S. gibberulus shells recovered from the site of Chelechol ra Orrak in Palau, western Micronesia, in deposits dating from ca. 3000 BP to the present. Statistical analysis indicates that in contrast to previous reports, there is a significant size increase for this taxon through time which may be the result of a combination of anthropogenic and environmental factors. We discuss variables influencing mollusc size and suggest that, given the complexities of their interactions and the data limitations of archaeomalacological assemblages, unambiguous determination of the cause(s) of molluscan size change may not always be possible.
Late Holocene human-induced modifications to a central Polynesian island ecosystem
Proceedings of the National Academy of …, 1996
A 7000-year-long sequence of environmental change during the Holocene has been reconstructed for a central Pacific island (Mangaia, Cook Islands). The research design used geomorphological and palynological methods to reconstruct vegetation history, fire regime, and erosion and depositional rates, whereas archaeological methods were used to determine prehistoric Polynesian land use and resource exploitation. Certain mid-Holocene environmental changes are putatively linked with natural phenomena such as eustatic