No abstract

Fossils of forest habitat beetles and leaves of Nothofagus menziesii provide evidence of a forest refugium at times between ca. 34 000 and ca. 18 500 cal. a BP at an upland site in Howard Valley, located adjacent to glaciated valleys in South Island, New Zealand. The stratigraphy of the glacial-aged terrace sequence of organic-rich silts and fluvial sand/gravels indicates that soil development occurred episodically for around 15 000 a. Fifty-four beetle taxa represent seven habitat types: forest, forest or scrub, riparian and aquatic, litter, grass/tussock, marshland and moss habitats. Leaf and beetle fossils indicate that forest dominated by N. menziesii persisted at the site for most of the time period represented, and tree line taxa such as Taenarthrus sp. 1 (Carabidae) and Podocarpus sp. (Podocarpaceae) indicate that the site may represent the upper tree limit for full-glacial time. The finding of forest at this elevated site adds to the growing fossil evidence for multiple forest refugia in New Zealand during the last glaciation and is consistent with the pollen records, which have consistently indicated the presence of forest species during the last glaciations.

No abstract

To investigate past vegetation change and human activity at the highest elevations on Easter Island, this study examines pollen, phytoliths, diatoms, starch and arthropods preserved in sediment/soil profiles from Rano Aroi crater, and another, newly described wetland in the adjacent, much smaller Rano Aroi Iti depression. A Bayesian age-depth model for Rano Aroi provides adequate certainty for the Late Pleistocene and last *1000 years, but is poorly constrained from 12,000 to 1000 cal BP. The occurrence of cf. Potamogeton and Lycopodium pollen types at this highland site (*425 m altitude), while absent or rare at lowland sites, could well be related to the cooler higher altitude conditions. Smaller quantities of Arecaceae (palm) pollen than at lowland sites indicate that this relatively high-altitude part of the island was near the altitudinal forest limit in the Late Pleistocene, with extensive Asteraceae-dominated shrubland. Arecaceae forest dominated the Holocene, for which there is evidence for a prolonged dry phase. The subsequent disappearance of charcoal and reappearance of diatoms, particularly Eunotia cf. pectinalis, suggest that the dry phase ended prior to human settlement. Polynesian activity is best constrained by abundant microscopic charcoal fragments beginning in a layer at 710 (2r: 645-797) cal BP, and suggesting a period of forest clearance and burning, culminating at 339 (2r: 177-428) cal BP. Thinner soils compared with lowland horticultural sites and 14 C dates of macroscopic Sophora charcoal suggest that the site was occupied after 1670 CE. Newly described terraces, and pollen, phytoliths and starch of cf. Broussonetia papyrifera (paper mulberry), cf. Colocasia esculenta (taro) and Musa (banana) sp. identified in this study show the value of a combined microfossil approach and provide evidence for extension of cultivation of these Polynesian-introduced cultigens to this least accessible part of the island. Rano Aroi Iti yielded a Bayesian 14 C age-depth chronology to a basal age of 1530-1314 cal BP, giving an unexpectedly old age for presumably introduced New World pollen of Sisyrinchium, which occurs throughout the core.

No abstract

Aim  The research aim is to reconstruct last glacial maximum (LGM) and Holocene vegetation history and ecology from fossil beetle assemblages. Location  The LGM and Holocene sites are located in the Awatere Valley, which lies in the tectonically active Marlborough Region in the north east of the South Island of New Zealand. Methods  Beetle fossils were extracted from silty organic sediment using the standard kerosene flotation method. Fossils were identified by comparisons made to modern species based on morphology and surface features. The ecology and distribution of modern analogues are extrapolated to reconstruct the fossil environment. Results  One hundred and forty‐five beetle species belonging to 33 families were identified. The LGM fossil fauna showed the local vegetation was characterized by a forest patch surrounded by an open tussock/grassland landscape. This Nothofagus (southern beech) forest persisted at the site until mid‐Holocene when it was replaced by a podocarp forest that contained high beetle diversity. Herbivores dominate in the early stage of this zone, indicating a relatively new forest environment. Later in the Holocene, the fauna is dominated by detritivores indicating an older more established forest. The late Holocene is characterized by low diversity and the absence of forest species. This fauna indicates that by 500 years ago, the forest was absent and is associated with an almost compete loss of beetle biodiversity. Main conclusions  The fossil beetles provide a unique perspective into the past environment in the Awatere Valley on a local scale. The reconstruction supports regional pollen interpretations of Holocene vegetation by identifying a specific forest patch. Fossil beetles are thus a valuable local proxy for vegetation reconstructions.

No abstract

Fossil beetles from two last interglacial lake deposits from southern Wairarapa, central New Zealand are provisionally ascribed to marine oxygen isotope stages (MIS) 5a–e. Both assemblages represent ecological successions from lake margins to forest. The lower sample (MIS 5e) is characterized by species found today in northern New Zealand. These species, including Lorelus crassicornis, ‘Dasytes’ laticeps, Cryptobius nitidius, ‘Stenomalium’ sulcithorax, Psilocnaeia nana, and Microbrontes lineatus, represent a southward displacement from modern distributions by up to 700 km. Climate reconstruction indicates that temperatures at the time of deposition were 1.6–2.5°C warmer in the summer (January) and 2.3–3.2°C warmer in the winter (July) than at present. These results match local and regional pollen and phytolith findings of warmer, wetter conditions at the thermal maximum of the last interglaciation. In contrast, the upper sample is characterized by species that have widespread modern-day distributions. This indicates that modern conditions were attained later in MIS5, after the MIS 5e thermal maximum.