Archaeological research has provided evidence of change in the settlement and subsistence practices of human groups inhabiting the Great Plains throughout the Holocene. A substantial part of this reorganization appears to be tied to concurrent changes affecting local bison populations, a species upon which these groups were uniquely dependant. Although bison are thought to have been strongly affected by the severe climates of the Mid-Holocene, there is an absence of appropriate models from which to interpret data in the archaeological and paleontological records. Nevertheless, new techniques are allowing for the determination of ecological information directly from prehistoric remains. This study uses stable isotope ratios (813C, 8'SN, 8D) in bone collagen to examine the dietary ecology of bison in Southern Saskatchewan during eight distinct time periods spanning the last 9,000 years. Stable isotopes of hydrogen and nitrogen in the tissues of animals relate to aspects of local climate, while stable-carbon isotope values reflect dietary choices. When employed in a comparative fashion, these sources may be used to construct simple models of foraging behaviour.<p> The environmental data developed from this investigation appear to correlate generally with patterns predicted by conventional models of Holocene climate. Nevertheless, at least one period of unexpectedly moderate temperature was identified from a context dating to the and Mid-Holocene. The ecological impact of such an episode may have been significant. In addition, the results of this study suggest that bison diet has a complex relationship with local climate. Changes in plant distribution resulting from variations of temperature and precipitation appear to have less of an impact upon bison consumption patterns than do climatically induced changes in the nutritional quality of vegetation. Nevertheless, during specific time periods characterized by similar climatic regimes, their relative consumption of certain forage species (C3 and C4 plants) does not appear to have been consistent. Such a discrepancy may reflect adaptive differences between bison from distinct time periods, or alternatively, the effects of a climatic difference undetectable by isotopic means. In either case, it would appear that bison of the past may have been subject to significant nutritional stresses that could have caused them to behave in fundamentally different ways from modern populations.

Archaeological research has provided evidence of change in the settlement and subsistence practices of human groups inhabiting the Great Plains throughout the Holocene. A substantial part of this reorganization appears to be tied to concurrent changes affecting local bison populations, a species upon which these groups were uniquely dependant. Although bison are thought to have been strongly affected by the severe climates of the Mid-Holocene, there is an absence of appropriate models from which to interpret data in the archaeological and paleontological records. Nevertheless, new techniques are allowing for the determination of ecological information directly from prehistoric remains. This study uses stable isotope ratios (813C, 8'SN, 8D) in bone collagen to examine the dietary ecology of bison in Southern Saskatchewan during eight distinct time periods spanning the last 9,000 years. Stable isotopes of hydrogen and nitrogen in the tissues of animals relate to aspects of local climate, while stable-carbon isotope values reflect dietary choices. When employed in a comparative fashion, these sources may be used to construct simple models of foraging behaviour.<p> The environmental data developed from this investigation appear to correlate generally with patterns predicted by conventional models of Holocene climate. Nevertheless, at least one period of unexpectedly moderate temperature was identified from a context dating to the and Mid-Holocene. The ecological impact of such an episode may have been significant. In addition, the results of this study suggest that bison diet has a complex relationship with local climate. Changes in plant distribution resulting from variations of temperature and precipitation appear to have less of an impact upon bison consumption patterns than do climatically induced changes in the nutritional quality of vegetation. Nevertheless, during specific time periods characterized by similar climatic regimes, their relative consumption of certain forage species (C3 and C4 plants) does not appear to have been consistent. Such a discrepancy may reflect adaptive differences between bison from distinct time periods, or alternatively, the effects of a climatic difference undetectable by isotopic means. In either case, it would appear that bison of the past may have been subject to significant nutritional stresses that could have caused them to behave in fundamentally different ways from modern populations.

Kangaroos are the world's most diverse group of herbivorous marsupials. Following late-Miocene intensification of aridity and seasonality, they radiated across Australia, becoming the continent's ecological equivalents of the artiodactyl ungulates elsewhere. Their diversity peaked during the Pleistocene, but by approximately 45,000 years ago, 90% of larger kangaroos were extinct, along with a range of other giant species. Resolving whether climate change or human arrival was the principal extinction cause remains highly contentious. Here we combine craniodental morphology, stable-isotopic, and dental microwear data to reveal that the largest-ever kangaroo, Procoptodon goliah, was a chenopod browse specialist, which may have had a preference for Atriplex (saltbushes), one of a few dicots using the C4 photosynthetic pathway. Furthermore, oxygen isotope signatures of P. goliah tooth enamel show that it drank more in low-rainfall areas than its grazing contemporaries, similar to modern saltbush feeders. Saltbushes and chenopod shrublands in general are poorly flammable, so landscape burning by humans is unlikely to have caused a reduction in fodder driving the species to extinction. Aridity is discounted as a primary cause because P. goliah evolved in response to increased aridity and disappeared during an interval wetter than many it survived earlier. Hunting by humans, who were also bound to water, may have been a more decisive factor in the extinction of this giant marsupial.

Sumatran elephant (Elephas maximus sumatranus) populations continue to decline due to habitat loss, poaching and conflict with humans. In Sumatra, elephant populations are fragmented into small isolated populations and increasingly cause conflict with humans. Yet, habitat loss due to the rapid land conversion for development is continuing an alarming situation. Developing effective land conservation strategies for elephants is difficult because there is little information available on foraging ecology, habitat use, movements and home range behaviors. I conducted a study on these topics in Seblat, Bengkulu Province, Sumatra during 2007-2008. The five important families of plants in the elephant diet in Sumatra ar: Moraceae, Arecaceae, Fabaceae, Poaceae,and Euphorbiacea. Elephants in Seblat tend to browse more than graze and elephants tend to browse more during the wet season. The nutritional quality (Crude Protein, Calcium, Phosphorus and Gross Energy) of elephant diet in Seblat is suitable to support population reproduction and growth. Home range size of one telemetered 97.4 km2 for the MCP and 95.0 km2 for the 95% fixed kernel. There was no relation between average monthly elephant home range sizes and rainfall, nor any correlation between monthly elephant movement distances and rainfall. Vegetation productivity, as measured by the Enhanced Vegetation Index (EVI), was probably the factor most affecting elephant movements compared to the distances to rivers and ex-logging roads on the SECC. Resource selection analyzes indicate that elephants in Seblat seem to select medium canopy and open canopy areas more than expected. Similarly, habitat ranking using compositional analysis shows that in 2nd order and 3rd order selection, medium canopy and open canopy were the two habitat types with a greater level of used. Habitat use based on diurnal and nocturnal elephant activities indicates that elephants preferred closed canopy habitat compare to the open canopy habitat during the day. The results of this study suggest wide conservation implications for elephants on Sumatra, helping to guide effective land use conservation programs and provide scientific guideline to restore disturbed habitat and select priority areas for Sumatran elephants.