Higher Effective Precipitation Research Articles

Holocene heathland development in temperate oceanic Southern Hemisphere: Key drivers in a global context

AbstractAimUnderstanding long‐term heathland development is key in mitigating their current attrition globally. However, such knowledge is limited in Australia and the wider Southern Hemisphere. We aim to identify potential climatic and environmental drivers of Holocene heathland development in temperate‐oceanic Australia (Bass Strait), and also assess the applicability of Iversen's conceptual model of interglacial vegetation development to the area.LocationBass Strait, southeast Australia.TaxonMonotoca, Epacris, Sprengelia and Restionaceae.MethodsWe used multiple sedimentary pollen and charcoal records from truwana/Cape Barren Island (CBI) in Bass Strait to reconstruct vegetation and fire history. We also used rarefaction analysis on pollen records to estimate floristic richness for all sites, and magnetic susceptibility and organic content were derived for two of the four sites as proxies for local sedimentary changes. Reconstructed vegetation and fire histories were then compared to independent records of climate and sea‐level change in temperate Australia, using a Detrended Correspondence Analysis ordination, to identify major drivers of heathland development.ResultsMajor heathland expansion occurred on truwana/CBI between the early and mid‐Holocene in response to sea‐level rise, high effective precipitation, reduced seasonality and increased Indigenous burning. Increasing seasonality, low effective precipitation, El Niño‐Southern Oscillation intensification, stable sea level, and decreased fire activity drove the expansion of scrub and woodland at the expense of heathland in the late Holocene. The overall vegetation development on truwana/CBI fits poorly with the classic Iversen conceptual model of interglacial vegetation development in the Northern Hemisphere, due to the significant role of interglacial sea‐level rise on truwana/CBI. Therefore, a modified model, which takes into account the role of sea‐level change, is proposed for Southern Hemisphere‐temperate‐oceanic settings.Main conclusionsHeathland developments in both hemispheres reflect some level of homogeneity, considering the roles of increased Indigenous burning and reduced seasonality in both hemispheres. Frequent, controlled burning strategies are recommended to maintain heathland on truwana/CBI.

A late-Holocene multiproxy fire record from a tropical savanna, eastern Arnhem Land, Northern Territory, Australia

Fire has a long history in Australia and is a key driver of vegetation dynamics in the tropical savanna ecosystems that cover one quarter of the country. Fire reconstructions are required to understand ecosystem dynamics over the long term but these data are lacking for the extensive savannas of northern Australia. This paper presents a multiproxy palaeofire record for Marura sinkhole in eastern Arnhem Land, Northern Territory, Australia. The record is constructed by combining optical methods (counts and morphology of macroscopic and microscopic charcoal particles) and chemical methods (quantification of abundance and stable isotope composition of pyrogenic carbon by hydrogen pyrolysis). This novel combination of measurements enables the generation of a record of relative fire intensity to investigate the interplay between natural and anthropogenic influences. The Marura palaeofire record comprises three main phases: 4600–2800 cal BP, 2800–900 cal BP and 900 cal BP to present. Highest fire incidence occurs at ~4600–4000 cal BP, coinciding with regional records of high effective precipitation, and all fire proxies decline from that time to the present. 2800–900 cal BP is characterised by variable fire intensities and aligns with archaeological evidence of occupation at nearby Blue Mud Bay. All fire proxies decline significantly after 900 cal BP. The combination of charcoal and pyrogenic carbon measures is a promising proxy for relative fire intensity in sedimentary records and a useful tool for investigating potential anthropogenic fire regimes.

Rock magnetic constraints for the Mid-Miocene Climatic Optimum from a high-resolution sedimentary sequence of the northwestern Qaidam Basin, NE Tibetan Plateau

The thick sequence of Cenozoic deposits in the Qaidam Basin of the NE Tibetan Plateau has great potential for understanding the tectonic and climatic evolution of the region. In this study, we performed detailed rock magnetic analyses of a well-dated (~20.7–11.2 Ma) Upper Cenozoic sedimentary sequence from the Huatugou (HTG) section in the NW Qaidam Basin. The magnetic susceptibility of the sequence is relatively low before 17.4 Ma, high during 17.4–14.5 Ma, and lower after 14.5 Ma again. This pattern is consistent with the occurrence of the Mid-Miocene Climatic Optimum (MMCO) during 17.4–14.5 Ma, with global climatic cooling thereafter. Measurements of multiple rock magnetic parameters indicate a peak in the concentration of fine-grained magnetic minerals during 17.4–14.5 Ma. This feature demonstrates that the enhancement of the magnetic susceptibility is due to the pedogenic production of superparamagnetic (SP) and single domain (SD) magnetite, suggesting the occurrence of relatively high effective precipitation and high temperature in the Qaidam Basin at this time. Comparing with regional and global climatic records, the warm and humid climatic conditions coincide with the MMCO, implying that global climate changes were responsible for the climatic evolution in the Qaidam Basin throughout the MMCO. However, after 14.5 Ma, the rapid uplift of the northern Tibetan Plateau caused it to reach a critical elevation which blocked the moisture supply to the Qaidam Basin and may also have contributed to the observed climatic changes.

Iron oxide characteristics of mid-Miocene Red Clay deposits on the western Chinese Loess Plateau and their paleoclimatic implications

The middle Miocene climate optimum (MMCO, 14.3–16.3Ma) was a warm climatic interval that may provide an analog for future climates in the context of ongoing global warming. In continental regions, however, reconstruction of the MMCO remains controversial due to the lack of robust proxies from continuous sedimentary sequences. In this study, we investigated the composition and relative abundance of pedogenic iron oxides in the Zhuanglang Red Clay deposits from the western Chinese Loess Plateau, using rock magnetic, color reflectance, and geochemical analyses. Our aim was to assess the climatic sensitivity of iron oxides in order to produce robust proxies for reconstructing regional temperature and moisture relationships during the MMCO. Our results indicate that the MMCO in the study region was characterized by high effective precipitation, relatively high temperature and strong pedogenesis, suggesting a strong East Asian summer monsoon (EASM). The strengthening of the EASM intensity during the MMCO is consistent with records of enhanced terrigenous chemical weathering in the South China Sea, and the occurrence of a relatively warm and humid climate on a global scale, implying the strong coupling between Asian monsoon evolution and global climate change during the middle Miocene. In addition, the magnetic susceptibility record of the Zhuanglang Red Clay demonstrates that eccentricity played the dominant role in controlling the EASM during the MMCO.

A 13 000 year multi‐proxy climate record from central Utah (western USA), emphasizing conditions leading to large mass movements

Younger Dryas to earliest Holocene mega‐landslides (>10 km2) in the eastern Fish Lake Plateau of central Utah required unusually wet conditions to drive movement. The sediment from abundant small lakes, ponds and especially fens that formed in swales between hummocks on the landslide surfaces are excellent archives of past climate. An integrated geophysical, geochemical and micro‐palaeontological investigation characterized fen deposits, determining the timing of mass movement and establishing the subsequent climate history of the region. High‐resolution P‐(compressional) wave surveys of fen deposits were conducted to image fen‐landslide contacts. Past climate states were assessed through loss on ignition, pollen and diatom abundances. Diatoms, in particular, record large variations in precipitation as the present‐day wetland switched from fen (intermittent standing water) to pond states in response to variable precipitation. One core was analysed for detailed climate proxies. A wet episode (pond) prevailed from 11.5 to 10 ka after which the climate became much drier (fen) until 6 ka due to weakening of the North American Monsoon. After 2.5–2.0 ka, reduced insolation produced cooler summers and wet winters (pond). Only recently (<500 years) has a fen re‐emerged based on direct observation and the disappearance of diatoms that require standing water. 14C ages of basal sediment from four cores show two episodes of movement: 12.8–12.5 and 10.5 ka. The earlier ages indicate that Younger Dryas high effective precipitation caused mass wasting. Later, during early Holocene times, colder winters followed by warmer summers and vigorous monsoons drove movement as rapid spring snow‐melt was followed by wet summers. In broad terms, this work highlights variable climate conditions that can drive mass movement, as well as the sensitivity of diatom records in fens to effective precipitation.

Drought severity in intensive agricultural areas by means of the EDI index

Abstract The aim of this work was the evaluation of drought severity development in the Czech Republic for the period 1971-2015 by the means of the Effective Drought Index (EDI). Annual values of the EDI index were determined using the method of effective precipitation for 14 localities spread throughout the Czech Republic (Central Europe). The seven categories were created according to obtained index values for the drought conditions determination for years during the period 1971-2015 through the percentile method. The annual index values were compared with acquired 2nd, 15th, 45th, 55th, 85th and 98th percentiles. Both the years with precipitation unfavourable conditions: 1972, 1973, 1984, 1990, 1991, 1992, 1993 and 2015 and the years with precipitation favourable conditions: 1977, 1987, 1995, 2001, 2002 and 2010 were determined. Precipitation conditions in the growing season from 61st to 180th day of the year were also analysed. This evaluation was conducted during the period 1971-2015 through the ten-day index values which were compared with acquired 2nd, 15th, 45th, 55th, 85th and 98th percentiles. Dry growing seasons occurred in 1973, 1974, 1976 and 1993. Wet growing seasons occurred in 1987, 2006 and 2010. Trend analysis of annual index values was performed through the Mann-Kendall test. Highly statistically significant increasing linear trends (P < 0.01) were found for four localities (Uherský Ostroh, Vysoká, Znojmo-Oblekovice and Žatec); statistically significant increasing trends (P < 0.05) were found for three localities (Brno-Chrlice, Lednice and Lípa). Based on the extrapolation of the trend, a slightly higher effective precipitation can be expected during the year in a substantial part of the country. However, these findings do not necessarily mean an optimal supply of agricultural land with water. Precipitation exhibits considerable unevenness of distribution through time. Given the increasing evapotranspiration demands of the environment their availability is limited.

The Middle–Late Pleistocene Bridgewater Formation on Cape Bridgewater, south-western Victoria: chronostratigraphy and palaeoclimatic significance

The Pleistocene Bridgewater Formation is well exposed at Cape Bridgewater and surrounding areas in south-western Victoria, where field studies, mineralogical and isotopic analyses and OSL dating have shown that it can be divided into three members, here named (in stratigraphic order) the Descartes Bay, Bats Ridge and Duquesne members. Each member consists of aeolian calcarenite deposited as a coastal dune, that was karstified (with solution pipe development) and then overlain by a red or purple palaeosol. The aeolianites were deposited in three distinct phases corresponding to interglacials MIS 11, MIS 9 and MIS 7, respectively, when the shoreline was near present sea level. Karstification occurred as a result of the high effective precipitation characteristic of the transition between interglacial and glacial periods, followed by aeolian dust accession and palaeosol formation during the drier, windier glacial climates. Comparison with the coeval Tamala Limestone in south-western Western Australia shows simultaneous changes in palaeoclimate: high effective precipitation during the transition from MIS 11 to MIS 10, and a relatively dry transition from MIS 9 to MIS 8. Abundant rainfall during MIS 5 caused extensive limestone dissolution (solution pipes in Victoria, pinnacles in Western Australia) and the resulting quartz sand residue was redeposited during MIS 2-4.

A late glacial Antarctic climate teleconnection and variable Holocene seasonality at Lake Pupuke, Auckland, New Zealand

We present the first continuous paleolimnological reconstruction from the North Island of New Zealand (37°S) that spans the last 48.2 cal kyr. A tephra- and radiocarbon-based chronology was developed to infer the timing of marked paleolimnological changes in Lake Pupuke, Auckland, New Zealand, identified using sedimentology, magnetic susceptibility, grain size and geochemistry (carbon, nitrogen and sulphur concentrations and fluxes, carbon and nitrogen stable isotopes). Variable erosional influx, biomass and benthic REDOX conditions are linked to changing effective precipitation and seasonality within three inferred broad intervals of climatic change: (1) the Last Glacial Coldest Phase (LGCP) of reduced effective precipitation and cooler temperatures, from 28.8 to 18.0 cal kyr BP, (2) the Last Glacial Interglacial Transition (LGIT) of increasing effective precipitation and warmer conditions, from 18.0 to 10.2 cal kyr BP, and (3) a Holocene interval of high effective precipitation, beginning with a warm period of limited seasonality from 10.2 cal kyr BP and followed by increasing seasonality from 7.6 cal kyr BP. The LGCP and LGIT also contain millennial-scale climate events, including the coldest inferred glacial conditions during the LGCP from 27.8 to 26.0 and 22.0–19.0 cal kyr BP, and a climate reversal in the LGIT associated with lower lake level, from 14.5 to 13.8 cal kyr BP, coeval with the Antarctic Cold Reversal. The onset of seasonal thermal stratification occurred at 5.7 cal kyr BP and was linked to natural eutrophication of Lake Pupuke, which produced enhanced organic sedimentation.

Late Quaternary environmental reconstructions of playa-lunette system evolution on the central High Plains of Kansas, United States

Playas are small, ephemeral wetlands found throughout semiarid and arid regions around the world. Lunettes are dunes that form downwind of some large playas. Two playa-lunette systems on the High Plains were investigated to reconstruct paleoenvironments during playa-lunette system evolution. Both playa-lunette systems are composed of sediment spanning >40 k.y., with earliest deposits accumulating during at least marine isotope stage (MIS) 3, and possibly starting as early as MIS 5. The Gilman Canyon Formation pedocomplex, dating between 42 and 28 ka, dominates this period and is ubiquitous throughout the playa-lunette systems. Climate during MIS 3 was similar to modern, with warm temperatures, low effective moisture, and playa floors exposed long enough to allow pedogenesis. During MIS 2, climate was relatively cool with higher effective precipitation, and playas were inundated for longer periods. The regionally expressed Brady Soil of the Pleistocene-Holocene transition caps these deposits and dates between 11.8 and 9.4 ka. During the Pleistocene-Holocene transition, climate warmed, yet moisture availability remained relatively high. Several distinct shifts in δ 13 C identify rapid climate changes associated with the Bolling-Allerod–Younger Dryas chronosequence. Warming continued into the Holocene, though moisture availability was highly variable. Holocene soils are common and date between 8.3 and 3.6 ka. Playa-lunette system stratigraphy represents a continuum of the upland loess sequence, though deposits are altered by playa hydrology. Geomorphic processes alternated between dissolution- and fluvial-eolian–driven processes as climate changed and playas developed. Due to the aggradational environment and sensitivity of these systems, high-resolution records of environmental change throughout their evolution are preserved.

Seven million years of wind and precipitation variability on the Chinese Loess Plateau

Recent studies of the eolian deposits in northern China have extended the East Asian monsoon history back to the early Miocene. However, the relative intensities of monsoonal winds and precipitation and the extent of their coupling prior to the Pleistocene epoch remain poorly constrained, mainly due to uncertainties in the interpretation of proxy indices generated from the Mio–Pliocene Red Clay sequences. Here we reconstruct East Asian monsoon oscillations over the past 7 Ma using magnetic susceptibility and carbonate content as summer monsoon (precipitation) proxies, and quartz grain size as a winter monsoon (wind intensity) index. Our results suggest that precipitation and wind intensity exhibited significant orbital-scale variations prior to 4.2 Ma, followed by slightly damped variability between 4.2 and 2.75 Ma. Subsequently, East Asian monsoon circulation experienced two large shifts at about 2.75 and 1.25 Ma, characterized by stepwise strengthening of glacial wind and interglacial precipitation. A remarkable change in East Asian monsoon seasonality occurred around 3.15–2.75 Ma. Prior to 3.15 Ma, strong winds were positively correlated with high effective precipitation, whereas after 2.75 Ma strong winds were negatively correlated with heavy precipitation. This shift was probably induced by a change from an insolation-forced system to one strongly influenced by the combined effects of the phased uplift of the Himalaya–Tibetan Plateau and the simultaneous development of the Northern Hemisphere ice sheets.

Oxygen and carbon isotope composition of authigenic carbonate from an Ethiopian lake: a climate record of the last 2000 years

The oxygen and carbon isotope composition of sedimentary carbonates formed in Lake Hayq, a closed-basin lake in northern Ethiopia, suggests marked variation in the balance between precipitation and evaporation during the last 2000 years. Diatom stratigraphy shows that the lake remained deep enough to support planktonic taxa, and was never saline. The record suggests that rainfall was higher than that of the twentieth century during most of this time, especially during two short intervals centred on AD 700 and AD 1300. Climate was drier only around AD 800, and from AD 1750—1900. Similar, but slightly moister climate than today, with high interdecadal variability, prevailed from AD 800 to AD 1200, equivalent to the European `Mediaeval Warm Period'. A period of high effective precipitation followed, from AD 1200 to AD 1700, during the `Little Ice Age'. Pollen evidence suggests that increased forest cover from AD 1400 to AD 1750 was a response to higher rainfall; forest cover may have increased evaporative loss from the catchment, contributing to a subsequent trend of increasing lakewater δ18O values.The record shows similarities in the timing and direction of changes in proxy-climatic records from Lake Naivasha (Kenya) and from the Nile.

A chronology for the long pollen record from Lake Wangoom, western Victoria (Australia) as derived from uranium/thorium disequilibrium dating

AbstractThe chronology of a long pollen record from Lake Wangoom, one of the few long palaeoenvironmental records from southeastern Australia, is discussed in light of the acquisition of new uranium/thorium disequilibrium (UTD) dates. Of crucial importance has been the estimation of ages for two major pre‐Holocene phases of forest expansion recorded in the sequence, with implications for the timing of periods of high effective precipitation in the region. The new UTD ages indicate that the oldest forest phase falls within the Penultimate Interglacial whereas the later phase corresponds with the Last Interglacial. This is older than indicated by previously reported UTD and radiocarbon dates, but confirms a chronology based on direct correlation with the pollen record from marine core E55‐6. The new chronology of the Lake Wangoom sequence provides evidence that phases of sustained forest development in southeast Australia relate to interglacial periods. In comparison, interstadial periods appear to be characterised by only minor arboreal development. Marked differences in the pattern of vegetation development evident in each of the interglacials are thought to reflect varying climatic and anthropogenic influences. Copyright © 2002 John Wiley & Sons, Ltd.

The late Quaternary vegetation history of the south‐central highlands of Victoria, Australia. II. Sites below 900 m

AbstractThe late Quaternary vegetation communities of the south‐central highlands of Victoria are constructed from analyses of pollen and charcoal, and macroscopic plant remains preserved in Sphagnum bogs. The sites, located in eucalypt forest or woodland, form an altitudinal sequence with the component Eucalyptus species varying with altitude and with small pockets of Nothofagus cunninghamii (Hook.) Oerst. in close proximity to the higher sites. The record from the sites above 900 m covers the last 32 000 years, and the record from the lower sites extends from at least 12 000 BP. Around 32 000 BP the region was predominantly covered by a mosaic of alpine feldmark and herbfield, with small patches of Eucalyptus and Nothofagus woodland close to sea level when summer temperatures were probably 5°C lower than present. Lowest values, probably 7°–8°C below present, occurred between 19 800 and 16 900 BP, when alpine communities were most widespread and much of the Central Highlands was treeless. Around 12 000 BP alpine taxa disappeared or were greatly reduced, first at the lower sites. There was an associated rise in the treeline with the movement upslope of Nothofagus and eucalypt forest as a result of a general increase in temperature and probably effective precipitation. By 6000 BP wet eucalypt forest and Nothofagus reached their maximum postglacial extent at all sites, possibly related to a further increase in temperature, at least 2°C lower than present, and higher effective precipitation. A continuing increase in temperature, or an increase in continentality, and a decrease in effective precipitation led to increased fire hazard and retraction of rainforest and wet sclerophyll or tall open forest toward present‐day values. Nothofagus disappeared from the sites below 900 m. The activities of humans pose further threats to remaining forest communities. The record of vegetation and environmental change derived from the local and regional picture from eight sites reinforces and complements that from the individual sites. For example, combining the records overcomes to some extent taphonomic problems such as the effect of streams that flow close to all sites, and other limitations including problems of dating, poor preservation and variable sedimentation rates.

Late Wisconsin and Holocene Subalpine Forests of the Markagunt Plateau of Utah, Southwestern Colorado Plateau, U.S.A.

The vegetation and climatic history of subalpine forests on the Colorado Plateau is documented from Lowder Creek Bog and Alpine Pond on the Markagunt Plateau. Pollen and macrofossil data demonstrate substantial changes at sites above 3150 m elevation during the last ca. 13,000 yr. During and after Late Wisconsin deglaciation, subalpine tree species (Picea engelmannii and Abies lasiocarpa) were rare or absent near the Lowder Creek Bog site, but nonarboreal species predominated. P. engelmannii–A. lasiocarpa forest became well-established there between 11,000 and 9800 yr BP and subalpine trees dominated this elevation throughout the Holocene. By ca. 8500 yr BP, however, Picea declined somewhat, with minimal pollen and macrofossil deposition occurring between ca. 8500 and 6400 yr BP. Picea trees may have thinned during this time or Picea may have expanded to higher elevations during this part of the Holocene, while Pinus ponderosa expanded at lower elevations. These changes were probably driven by warmer conditions with variable precipitation. Alternative explanations include hydroseral changes within the bog, or insect infestation on Picea. After ca. 6400 yr BP, more consistent Picea pollen influx suggests renewed importance around the bog, which has been maintained until the present. Abies lasiocarpa became more important after ca. 2700 yr ago.The pollen sequence supports an interpretation of high effective precipitation during the early Holocene, followed by warmer temperatures and somewhat variable precipitation after ca. 8500 yr BP. This sequence is most similar to other sites on and near the western, southern, and northeastern Colorado Plateau, where the maximum influence of monsoon activity may have declined by the end of the early Holocene. Declines in summer insolation probably contributed to Late Holocene cooling, with increasing effective precipitation at most sites, including Lowder Creek Bog.

Late Wisconsin and Holocene Subalpine Forests of the Markagunt Plateau of Utah, Southwestern Colorado Plateau, U.S.A.

The vegetation and climatic history of subalpine forests on the Colorado Plateau is documented from Lowder Creek Bog and Alpine Pond on the Markagunt Plateau. Pollen and macrofossil data demonstrate substantial changes at sites above 3150 m elevation during the last ca. 13,000 yr. During and after Late Wisconsin deglaciation, subalpine tree species (Picea engelmannii and Abies lasiocarpa) were rare or absent near the Lowder Creek Bog site, but nonarboreal species predominated. P. engelmannii–A. lasiocarpa forest became well-established there between 11,000 and 9800 yr BP and subalpine trees dominated this elevation throughout the Holocene. By ca. 8500 yr BP, however, Picea declined somewhat, with minimal pollen and macrofossil deposition occurring between ca. 8500 and 6400 yr BP. Picea trees may have thinned during this time or Picea may have expanded to higher elevations during this part of the Holocene, while Pinus ponderosa expanded at lower elevations. These changes were probably driven by warmer conditions with variable precipitation. Alternative explanations include hydroseral changes within the bog, or insect infestation on Picea. After ca. 6400 yr BP, more consistent Picea pollen influx suggests renewed importance around the bog, which has been maintained until the present. Abies lasiocarpa became more important after ca. 2700 yr ago.The pollen sequence supports an interpretation of high effective precipitation during the early Holocene, followed by warmer temperatures and somewhat variable precipitation after ca. 8500 yr BP. This sequence is most similar to other sites on and near the western, southern, and northeastern Colorado Plateau, where the maximum influence of monsoon activity may have declined by the end of the early Holocene. Declines in summer insolation probably contributed to Late Holocene cooling, with increasing effective precipitation at most sites, including Lowder Creek Bog.

Paleoclimatic Significance of Late Quaternary Lacustrine and Alluvial Stratigraphy, Animas Valley, New Mexico

Lacustrine and alluvial stratigraphic sequences in the southern Animas Valley of New Mexico allow reconstruction of late Quaternary climates. Four separate stands of late Quaternary Lake Cloverdale in the southern Animas Valley are recorded by lacustrine shoreline deposits. Soils and stratigraphic evidence show that three young lake highstands occurred during the Holocene and that a higher lake stand occurred 18,000 to 20,00014C yr B.P. Fluvial systems aggraded the southern Animas Valley during the middle to late Holocene. The late Quaternary stratigraphy shows that several periods during the late Holocene were characterized by higher effective precipitation than at any time since the last glacial maximum.

A Vegetation History and Quantitative Estimate of Holocene Climate from Chapple Vale, in the Otway Region of Victoria, Australia

A well-dated pollen record from Chapple Vale in the north of the Otway region provides a detailed history of vegetation and environments through the last c. 7000 years. From the commencement of the record, a stand of cool temperate rainforest, dominated by Nothofagus cunninghamii (Hook.) Oerst., grew on or around the site and was surrounded by eucalypt-dominated tall open forest. Between c. 5200 and 4600 years BP (before present), the rainforest declined and tall open forest predominated. Some time after 4400 years BP there was a major and consistent increase in charcoal values, suggesting an increase in burning, the progressive development of scrub–heath vegetation on site and the replacement of tall open forest vegetation by eucalypt woodland surrounding the site. The fossil evidence for N. cunninghamii on the site and its present restriction to wetter areas and gullies of the Otway Ranges indicate, from the application of the present bioclimatic range of the species, a mean annual temperature and winter temperatures that were c. 1˚C cooler than present, and summer temperatures that were possibly slightly cooler than present, together with a much higher effective precipitation from the commencement of the record until c. 4600 years BP. These climatic estimates are in accord with those derived from a similar study of changing distributions of N. cunninghamii in the Central Highlands of lower mean annual and cooler summer temperatures and higher effective precipitation over this time span. However, for winter, the evidence is equivocal. While the Otway estimates suggest lower temperatures, the Central Highlands findings show slightly higher temperatures. Taking into account additional present-day records for N. cunninghamii, it is likely that the Otway estimates are the most reliable.