177 research outputs found

    Overlapping Scales of Place Based Indigenous Knowledge and Hydroclimate in Australia

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    Indigenous Peoples have been monitoring and adapting to uncertainty and change in their local regions for millennia, resulting in a holistic view of the interlinkages within the occupied complex socio-environmental systems. This research consists of investigating the overlapping scales of knowledge within Indigenous Australian seasonal calendars and colonial methods of hydroclimate assessment for improving adaptability to climate change impacts. The analyses began with a sample of 25 Indigenous seasonal calendars providing a glimpse into interlinkages among biota, environment, and meteorology of the localised regions. Across the calendars, five themes of information and multiple categories within these themes became apparent and were explored for relevance to climate change and adaptability. The next stage of research involved analysis and modelling of historical streamflow and observed historical streamflow for changes in trends and seasonality. Quantile regression and cluster analysis results indicate widespread decreases in streamflow across all seasons in the south half of the continent while streamflow in the northern region shows marked local coherence in increases and decreases. Trends within the lower and upper quantiles of flow distributions revealed unique sub-seasonal time windows in the extremes, underscoring that systematic assessment of the entire spectrum of flow levels, and change therein, are necessary to understand vulnerability to human and environmental systems. Climate change is increasing the risk of droughts and bushfires through increasing variability and long-term trends in the local and remote ocean-atmospheric phenomena as represented by two climatic indices: Southern Ocean Index and Indian Ocean Dipole. These two indices, sea surface temperature, and historical Standardized Precipitation Evapotranspiration Index were used to assess the nature of variability and spatial patterns in the bushfire season, as delineated from five Indigenous seasonal calendars. Results indicated increased water stress across the four eastern locations during the bushfire season while the western location is experiencing a change in rainfall seasonality. Indigenous place-based knowledge has substantial awareness of the holistic interlinkages that make up the biota, environment, and climate of a region. Collaboration with knowledge holders on resource stewardship has the potential to improve adaptability of humans and ecological systems to the increasing challenges brought by climate change

    Introduction to New Zealand

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    New Zealand consists of a cluster of islands, the three largest being North, South, and Stewart, in the southwest Pacific Ocean. They have a total land area of about 270 000 km2 (similar to that of the British Isles or Japan). The islands are the small emergent parts of a much larger submarine continental mass (Fig. 0.1) that was rafted away from Australia and Antarctica by sea-floor spreading in the proto-Tasman Sea between 85 and 60 Ma. Much of this New Zealand subcontinent is a remnant of the former eastern margin of Gondwanaland, the ancient southern supercontinent. The mainland islands form a long, narrow, NE-SW trending archipelago bisected by an active, obliquely converging, boundary between the Australian and Pacific lithospheric plates (Fig. 0.2), which has evolved over the last 25 million years (Kamp 1992). The plate boundary is marked by active seismicity and volcanic arcs, illustrating New Zealand's position as part of the Circum-Pacific Mobile Belt -the so-called "Pacific Ring of Fire". The NE-SW trend of the modem plate boundary cuts across mainly NW-SE oriented structural features inherited from earlier (mid-Cretaceous) rifting events

    Identification of arid phases during the last 50 kyr Cal BP from the Fuentillejo maar lacustrine record (Campo de Calatrava Volcanic Field, Spain).

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    Geochemical (element analysis, molecular analysis of organic compounds), physical, palynological, mineralogical and sedimentary facies analysis were performed to characterise the sedimentary record in Fuentillejo maar-lake in the Central Spanish Volcanic Field of Campo de Calatrava, in order to reconstruct the palaeoenvironmental and palaeoclimatic processes which controlled vegetation patterns and deposition of different sedimentary facies. The upper 20 m of core FUENT-1 show variations in clastic input, water chemistry, vegetation and organic fraction sources in the lake throughout the Late Pleistocene and Holocene. The temporal framework provided by14C accelerator mass spectrometry dating allows assigning the sequence to the last 50 cal. ka BP. Arid phases identified in the FUENT-1 sequence are correlated to Heinrich events (HE) and to stadials of the Dansgaard/Oeschger (D/O) cycles. Siliciclastic facies with high magnetic susceptibility values, high Juniperus pollen content, a low Paq index (aquatic macrophysics proxy index), a decrease in the relative percentage of the n-C27 and an increase in the n-C31 alkanes are indicative of arid and colder climatic events related to HE 2, HE 1 and the Younger Dryas (YD). Similar short cold and arid phases during the Holocene were identified at 9.2–8.6, 7.5–7 and 5.5–5 cal. ka BP. In dolomite–mud facies, the pollen data show an increase in the herbs component, mainly – Chenopodiaceae, Artemisia andEphedra – steppe taxa; a low Paq index, a decrease in the relative percentage of the n-C27 alkane and an increase in the n-C31 alkane are also observed. This facies was probably the result of lower lake levels and more saline–alkaline conditions, which can be interpreted as linked to arid–warm periods. These warm and arid phases were more frequent during Marine Isotope Stage (MIS) 3 and the interstadials of MIS 2. HE 4, HE 2, HE 1 and the YD in core FUENT-1 were immediately followed by increases of warm steppe pollen assemblages that document rapid warming similar to the D/O cycles but do not imply increasing humidity in the area. Fuentillejo hydrology is controlled by changes in the atmospheric and oceanic systems that operated on the North Atlantic region at millennial scale during the last 50 cal. ka B

    The application of resilience concepts in palaeoecology

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    The concept of resilience has become increasingly important in ecological and socio-ecological literature. With its focus on the temporal behaviour of ecosystems, palaeoecology has an important role to play in developing a scientific understanding of ecological resilience. We provide a critical review of the ways in which resilience is being addressed by palaeoecologists. We review ~180 papers, identifying the definitions or conceptualisations of ‘resilience’ that they use, and analysing the ways in which palaeoecology is contributing to our understanding of ecological resilience. We identify three key areas for further development. Firstly, the term ‘resilience’ is frequently defined too broadly to be meaningful without further qualification. In particular, palaeoecologists need to distinguish between ‘press’ vs. ‘pulse’ disturbances, and ‘ecological’ vs. ‘engineering’ resilience. Palaeoecologists are well placed to critically assess the extent to which these dichotomies apply in real (rather than theoretical) ecosystems, where climate and other environmental parameters are constantly changing. Secondly, defining a formal ‘response model’ - a statement of the anticipated relationships between proxies, disturbances and resilience properties - can help to clarify arguments, especially inferred causal links, since the difficulty of proving causation is a fundamental limitation of palaeoecology for understanding ecosystem drivers and responses. Thirdly, there is a need for critical analysis of the role of scale in ecosystem resilience. Different palaeoenvironmental proxies are differently able to address the various temporal and spatial scales of ecological change, and these limitations, as well as methodological constraints on inherently noisy proxy data, need to be explored and addressed.PostprintPeer reviewe

    Pollen, biomarker and stable isotope evidence of late Quaternary environmental change at Lake McKenzie, southeast Queensland

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    Unravelling links between climate change and vegetation response during the Quaternary is important if the climate–environment interactions of modern systems are to be fully understood. Using a sediment core from Lake McKenzie, Fraser Island, we reconstruct changes in the lake ecosystem and surrounding vegetation over the last ca. 36.9 cal kyr. Evidence is drawn from multiple sources, including pollen, micro-charcoal, biomarker and stable isotope (C and N) analyses, and is used to gain a better understanding of the nature and timing of past ecological changes that have occurred at the site. The glacial period of the record, from ca. 36.9 to 18.3 cal kyr BP, is characterised by an increased abundance of plants of the aquatic and littoral zone, indicating lower lake water levels. High abundance of biomarkers and microfossils of the colonial green alga Botryococcus occurred at this time and included large variation in individual botryococcene d13C values. A slowing or ceasing of sediment accumulation occurred during the time period from ca. 18.3 to 14.0 cal kyr BP. By around 14.0 cal kyr BP fire activity in the area was reduced, as was abundance of littoral plants and terrestrial herbs, suggesting wetter conditions from that time. The Lake McKenzie pollen record conforms to existing records from Fraser Island by containing evidence of a period of reduced effective precipitation that commenced in the mid-Holocene

    Expressions of climate perturbations in western Ugandan crater lake sediment records during the last 1000 yr

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    Equatorial East Africa has a complex, regional patchwork of climate regimes, with multiple interacting drivers. Recent studies have focussed on large lakes and reveal signals that are smoothed in both space and time, and, whilst useful at a continental scale, are of less relevance when understanding short-term, abrupt or immediate impacts of climate and environmental changes. Smaller-scale studies have highlighted spatial complexity and regional heterogeneity of tropical palaeoenvironments in terms of responses to climatic forcing (e.g. the Little Ice Age [LIA]) and questions remain over the spatial extent and synchroneity of climatic changes seen in East African records. Sediment cores from paired crater lakes in western Uganda were examined to assess ecosystem response to long-term climate and environmental change as well as testing responses to multiple drivers using redundancy analysis. These archives provide annual to sub-decadal records of environmental change. The records from the two lakes demonstrate an individualistic response to external (e.g. climatic) drivers, however, some of the broader patterns observed across East Africa suggest that the lakes are indeed sensitive to climatic perturbations such as a dry Mediaeval Climate Anomaly (MCA; 1000–1200 AD) and a relatively drier climate during the main phase of the LIA (1500–1800 AD); though lake levels in western Uganda do fluctuate. The relationship of Ugandan lakes to regional climate drivers breaks down c. 1800 AD, when major changes in the ecosystems appear to be a response to sediment and nutrient influxes as a result of increasing cultural impacts within the lake catchments. The data highlight the complexity of individual lake response to climate forcing, indicating shifting drivers through time. This research also highlights the importance of using multi-lake studies within a landscape to allow for rigorous testing of climate reconstructions, forcing and ecosystem response

    Holocene climate change in Glen Affric, Northern Scotland : a multi-proxy approach

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    A multi-proxy approach was used to generate a continuous, sensitive Holocene palaeoclimatic record for Glen Affric, north west Scotland. Fluctuations in lake-level were used as a proxy for shifts in precipitation. Rigorous site selection criteria and a new methodology were developed to interpret the lacustrine sediment record in terms of climatically driven changes in water depth by separating (a) allogenic from autogenic sediment inputs and (b) explicitly linking the marginal fen peat system responded to changes in lake-level. The sedimentary record from the lake site, Loch Coulavie, suggests that lake-level has fluctuated repeatedly throughout the Holocene. The comparative magnitude of changes in lake-level defined the relative intensity of shifts in precipitation. Variations in mire surface wetness, as determined through humification analysis, from a series of four hydrologically isolated ombrotrophic blanket mire sites through the east-west trending glen, were used to generate a record of changes in effective precipitation. A reliable radiocarbon chronology obtained from both proxy records allowed the synthesis of these data sets and the definition of Holocene climate change in terms of relative shifts in temperature and precipitation. The data suggests that the early Holocene was more stable in terms of both temperature and precipitation, but that after c. 6200 BP (7200 cal. BP) both temperature and precipitation became highly variable. Several short-lived, abrupt high intensity shifts to increased precipitation occur at c. 6200 BP (7200 cal. BP), c. 5000 BP (5700 cal. BP), c. 3000 BP (3200 cal. BP) and c. 2400 BP (2350 cal. BP). Holocene climatic variability within Glen Affric corresponds to records of changes in North Atlantic oceanic circulation patterns. The predominance of atmospheric systems, such as Atlantic westerlies, may also have controlled spatial climatic variability within the glen, with the periodic establishment of very steep west-east climatic gradients, steeper than at the present day

    The digital self: A qualitative approach to studying female college students\u27 use of social-networking platforms

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    The purpose of this research was to understand how female college students make use of social networks, specifically how they use the medium to connect with others. Researching socialnetworking use pertaining to the phenomenon of connection will give a richer understanding of female students’ lived experience of social networking. Many quantitative studies have been conducted about social networking, but more qualitative measures are needed to explore social networking. With the continuously changing social-networking platforms, there is little research that sheds light on social-networking use among female college students. My goal was to conduct a qualitative research study that examined female college students’ use of socialnetworking platforms, specifically how they use the medium to connect, by conducting an exploratory instrumental case study, using experience sampling and the VisionsLive qualitative software platform for data collection. My unit of analysis was six female college students attending a comprehensive Midwestern university. I sought to answer five research questions through my research: 1. What social-networking platforms are female college students using? a. Which social-networking platforms are female college students using most often? 2. How do female college students describe their social-networking use? 3. In what ways do college women describe connecting through social networks? a. Who are female college students connecting with through social-networking platforms? 4. How do female college students describe their needs, and how is social networking related to those needs? 5. How do female college students describe their feelings about the use of social-networking platforms and connecting? After synthesis of the data and development of the emergent themes, the core of how female college students are experiencing social networking to connect with others materialized. The emergent themes were: ‱ Connection happens on multiple levels and is used to maintain existing relationships;‱ Construction of shared meaning through virtual symbols; ‱ Shapes self-value/self-worth; ‱ Evokes feelings, both good and bad;‱ And wanting to be heard and understood. The essence of social-networking connection for these female participants was as a tool that evoked feelings and met needs, which is understood through the construction of shared meaning through virtual symbols
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