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Toowong, Australia

Pole M.,Queensland Herbarium
Palaeontologia Electronica | Year: 2014

Miocene New Zealand was a small, highly oceanic landmass which makes it ideal for recording terrestrial climate, free of the complications of a continental setting. Fortunately, it has a good Miocene fossil record, both marine and terrestrial. This paper reviews past conclusions about Miocene climate then attempts to derive some key climate indices for the period using a variety of plant fossil proxies. The paper looks at three slices of Miocene time-a broad early to earliest middle Miocene time, a restricted period in the middle Miocene, and broader middle-late Miocene. The results suggest early to earliest middle Miocene Mean Annual Temperatures (MATs) reached at least 17-18°C, thus, about 6-7°C warmer than today (coastal areas of southern New Zealand today have a MAT of about 11°C). At times Miocene MAT may have reached 19-20°C. These figures support the cooler estimates of New Zealand Miocene climate that have been made previously by using palebotanical proxies, rather than those based on marine invertebrates. Based on plant fossils there is no evidence that New Zealand ever reached truly 'tropical' (i.e., megathermal) conditions (> 24-25°C). The climate in the middle Miocene is confounded by signs of precipitation and temperature change, and the rarity of leaf fossils. However, the data suggest both cooling and drying from the early Miocene. The presence of crocodiles yet the disappearance of palms, suggests a MAT that was at the lower end of existence for both of these groups, perhaps about 14°C. By the late Miocene, there is evidence for significant cooling, both from leaf size and a drop in plant diversity, which resulted in vegetation dominated in many places by Nothofagus. © Palaeontological Association July 2014. Source

Silcock J.L.,University of Queensland | Piddocke T.P.,Queensland Herbarium | Fensham R.J.,University of Queensland
Biological Conservation | Year: 2013

The rapid spread of pastoralism across Australian and North American rangelands and the lack of reference sites mean that recurring arguments about the cause and magnitude of landscape change are frustrated by the rarity of records that predate the critical watershed of European settlement. The journals of European explorers from the 1840s are the first written descriptions of inland Australia. Prevailing paradigms based on a synthesis of published material relating to five key themes of environmental change are presented: vegetation structure, fire regimes, waterhole permanence, macropod abundance and medium-sized mammal assemblages. Six hypotheses relating to these themes were tested against the explorer record for inland eastern Australia. Nearly 4500 observations from fourteen journals spanning twelve expeditions between 1844 and 1919 were geo-referenced, using landscape features, distances, bearings and latitudes, combined with topographic maps and high-resolution satellite imagery. Careful evaluation of the record suggests little change in broad vegetation structure or waterhole permanence, running counter to prevailing paradigms. The sparse observations of fire suggest burning was infrequent and mostly restricted to creek-lines and higher-rainfall grasslands in the east and north of the study area and spinifex-dominated vegetation. Kangaroos were apparently uncommon in semi-arid areas where they are abundant today. The journals contain important observations of medium-sized mammals that are now extinct or rare. Our results highlight the importance of accurate geo-referencing compiled from entire journals of multiple explorers and contrasting the record with contemporary observation. Systematic evaluation of the explorer record for a region can provide ecological insights that are difficult to obtain by other means, and can be used to test prevailing assumptions common to arid systems that have been subject to abrupt management upheaval. © 2012 Elsevier Ltd. Source

Tosolini A.-M.P.,University of Melbourne | Pole M.,Queensland Herbarium
Alcheringa | Year: 2010

Mesofossil assemblages from several Cretaceous and Cenozoic units across Australia and New Zealand provide new evidence of insect and annelid behaviour. The earliest scale insects (Diaspididae, Coccoidea) from Australasia are described and represented by three scale morphotypes. The mesofossil assemblages also reveal clitellate annelid cocoon morphotypes, three morphotypes of arthropod coprolites and several insect piercement structures on gymnosperm leaf or stem fragments, possibly related to feeding or more likely oviposition. This research offers a new avenue for detecting cryptic terrestrial invertebrate groups and their interactions, particularly with plants, in the fossil record. The fossils demonstrate that insect/invertebrate activity can be preserved and identified in mesofossil suites, that such traces and exoskeleton fragments are relatively common in acid-extracted mesofossil suites, and that recognizable categories occur on multiple landmasses and at various ages. © 2010 Association of Australasian Palaeontologists. Source

Pole M.,Queensland Herbarium
Alcheringa | Year: 2010

This paper reports the discovery of three of the most iconic New Caledonian endemic genera, Amphorogyne, Paracryphia and Phelline, as dispersed leaf cuticle fossils in the early Miocene of New Zealand. New Caledonia's endemic angiosperm families have given it a reputation as one of the most interesting botanical regions in the world, but unfortunately it has no known pre-Pleistocene Cenozoic plant fossil record. A once more widespread distribution of its key plants in the context of a cooling and drying Neogene world suggests the current vegetation of New Caledonia is the result of contraction, or even a migration, from more southerly landmasses. Thus, New Zealand may have been a source of at least some of New Caledonia's plants. © 2010 Association of Australasian Palaeontologists. Source

Three new species of Pluchea Cass, are described; P. longiseta A.R.Bean from northern Western Australia, P. mesoles A.R.Bean from the Northern Territory, and P. alata A.R.Bean from central Queensland. All species are illustrated and distribution maps are provided. A revised key to the Australian of Pluchea species is provided. Source

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