Ellen Cieraad's Research

Quantative plant ecology & physiology

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Threatened Environment Classification

A goal of the New Zealand Biodiversity Strategy is to ‘halt the decline in New Zealand’s indigenous biodiversity, and to maintain and restore a full range of remaining natural habitats and ecosystems to a healthy functioning state’. Meeting this goal requires knowledge of how much of the full range of natural ecosystems remains, and how well they and their biodiversity components are protected. However, reliable information is surprisingly difficult to bring together at a national level.


One way to assess broad patterns of loss and protection of indigenous species habitats is to combine maps of land cover, legal protection status and the abiotic environment. The first such combination analysis was produced nearly 10 years ago, and was used to create a simple, six-category ‘Threatened Environment Classification’ that has been adopted by many agencies, decision-makers and private biodiversity practitioners across the country.

Recently, my colleagues and I revised and published an updated Classification with updated land cover (LCDB4.0; based on 2012 satellite imagery) and information on protected areas for natural heritage purposes (2012), which they combined with LENZ (Land Environments New Zealand). You can find our paper here. The new analysis shows that New Zealand’s lowest, flattest, warmest and driest environments have lost high proportions of their indigenous cover and what remains is poorly protected ‒ even less so than previously estimated. In contrast, the highest, steepest, coolest, and wettest environments have been less reduced by human land use and are much better protected ‒ more so than previously estimated.

Cieraad E, Walker S, Price R, Barringer J 2015. An updated assessment of indigenous cover remaining and legal protection in New Zealand’s land environments. New Zealand Journal of Ecology 39(2): 309-315.

The Threatened Environment Classification provides a high-level, standardised national framework for assessing biodiversity representativeness and protection that and can assist both planning and reporting. Land in the first two categories of the classification (less than 20% indigenous cover remaining) is recognised as a priority in biodiversity protection policy, especially on private land. In combination with site survey, the Classification can help resource managers to identify places that are priorities for formal protection against clearance and/or incompatible land uses, and for ecological restoration to restore linkages, buffers and lost species.

The Threatened Environment Classification is freely available, and can be accessed in several ways. The easiest way to view it and create maps is in Landcare Researches GIS portal Our Environment  (under “About Ecosystems and habitats” tick “Which areas of indigenous vegetation are under threat?”).

More information and resources are available on http://www.landcareresearch.co.nz/resources/maps-satellites/threatened-environment-classification


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Fossil ferns

Pikopiko Fossil Forest near Tuatapere in Southland may not be as well-known as the Curio Bay petrified forest but it has one of the richest known Cenozoic* fern floras globally. Walking in between the in situ fossil tree stumps (probably related to Araucaria) on the shores of the Wairau River, you get a sense of the spacing of the trees. Underneath your feet, the fossil litter layers provide insights into this ancient forest community. The diversity and abundance of ferns implies that ferns dominated the evergreen, tall forest understorey just as they do in modern New Zealand rainforests. Eight fern macrofossil groups (parataxa) and 20 very tiny spore types have been identified from the fossil forest. The ancient flora encompasses at least 40% of modern New Zealand fern families, which highlights the long history for some fern genera in the region. The abundance of ferns, the presence of fungi on many leaves and the presence of palms is evidence for warm humid conditions in Late Eocene New Zealand.


Pikopiko fossil forest

Colleagues of mine recently re-examined fossil fern material I used for my MSc thesis together with more fern macrofossils from these Eocene strata (c. 35 million years ago), the first records for New Zealand. The results are published here.

Homes AM, Cieraad E, Lee DE, Lindqvist JK, Raine JI, Kennedy EM, Conran JG 2015. A diverse fern flora including macrofossils with in situ spores from the Late Eocene of southern New Zealand. Review of Paleobotany and Palynology 220: 16-28. doi:10.1016/j.revpalbo.2015.04.007

The discovery of three types of fossil fern fronds bearing sporangia with in situ spores enabled us to roughly identify the ancient ferns and show for the first time that some relate to a present day fern genus (including Blechnum, and Thelypteris subgenus Cyclosorus), some to an extinct group of uncertain affinity and some to a widely known fossil spore form taxon. Five additional fern groups, including another probable Blechnum, could be distinguished on the basis of sterile foliage.

The fern flora recovered from Pikopiko Fossil Forest is significant in being the first record of fern macrofossils from Eocene strata (56 to 33.9 million years ago) in New Zealand, and they provide a wider understanding of the natural history of New Zealand during this time.

*The Cenozoic period is from 65 million years ago to the present day.

Photo credit: GNS