Search Results - (Author, Cooperation:A. N. Gillison)

2015-12-25

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Biodiversity ; Databases, Factual ; Genetic Variation ; Internationality ; Models, Biological ; Nitrogen/analysis ; Organ Size ; *Phenotype ; Plant Development ; Plant Leaves/anatomy & histology ; *Plant Physiological Phenomena ; Plant Stems/anatomy & histology ; Plants/*anatomy & histology/classification ; Reproduction ; Seeds/anatomy & histology ; Selection, Genetic ; Species Specificity

1432-1939

Key words Carnivorous plants ; Pitcher plants ; Insect nitrogen ; Nitrogen partitioning

Springer Online Journal Archives 1860-2000

Biology

Abstract This study investigated the nitrogen (N) acquisition from soil and insect capture during the growth of three species of pitcher plants, Nepenthes mirabilis, Cephalotus follicularis and Darlingtonia californica. 15N/14N natural abundance ratios (δ15N) of plants and pitchers of different age, non-carnivorous reference plants, and insect prey were used to estimate proportional contributions of insects to the N content of leaves and whole plants. Young Nepenthes leaves (phyllodes) carrying closed pitchers comprised major sinks for N and developed mainly from insect N captured elsewhere on the plant. Their δ15N values of up to 7.2‰ were higher than the average δ15N value of captured insects (mean δ15N value = 5.3‰). In leaves carrying old pitchers that are acting as a N source, the δ15N decreased to 3.0‰ indicating either an increasing contribution of soil N to those plant parts which in fact captured the insects or N gain from N2 fixation by microorganisms which may exist in old pitchers. The δ15N value of N in water collected from old pitchers was 1.2‰ and contained free amino acids. The fraction of insect N in young and old pitchers and their associated leaves decreased from 1.0 to 0.3 mg g−1. This fraction decreased further with the size of the investigated tiller. Nepenthes contained on average 61.5 ± 7.6% (mean ± SD, range 50–71%) insect N based on the N content of a whole tiller. In the absence of suitable non-carnivorous reference plants for Cephalotus, δ15N values were assessed across a developmental sequence from young plants lacking pitchers to large adults with up to 38 pitchers. The data indicated dependence on soil N until 4 pitchers had opened. Beyond that stage, plant size increased with the number of catching pitchers but the fraction of soil N remained high. Large Cephalotus plants were estimated to derive 26 ± 5.9% (mean ± SD of the three largest plants; range: 19–30%) of the N from insects. In Cephalotus we observed an increased δ15N value in sink versus source pitchers of about 1.2‰ on average. Source and sink pitchers of Darlingtonia had a similar δ15N value, but plant N in this species showed δ15N signals closer to that of insect N than in either Cephalotus or Nepenthes. Insect N contributed 76.4 ± 8.4% (range 57–90%) to total pitcher N content. The data suggest complex patterns of partitioning of insect and soil-derived N between source and sink regions in pitcher plants and possibly higher dependence on insect N than recorded elsewhere for Drosera species.

Electronic Resource

1572-9710

spatial modelling ; potential mapping ; distribution mapping ; Bettongs

Springer Online Journal Archives 1860-2000

Biology

This paper briefly reviews some limitations associated with the application of existing modelling procedures to conservation ecology, and describes a new procedure (DOMAIN) which avoids these problems. The procedure computes potential distributions based on a range-standardized, point-to-point similarity metric and provides a simple, robust method for modelling potential distributions of plant and animal species. DOMAIN offers advantages over similar methods in its ability to operate effectively using only presence records and a limited number of biophysical attributes. The use of a continuous similarity function gives DOMAIN increased flexibility as an heuristic tool, suitable for application in survey design, reserve selection and potential mapping of rare and common species. Potential distributions were computed for two Australian marsupial bettong species (Aepyprymnus rufescens ‘Gray’ and Bettongia tropica Wakefield) using DOMAIN and two alternative models. Of the three procedures, the DOMAIN model produced distribution patterns that were most consistent with the known ecology of the species, and most appropriate for survey design.

Electronic Resource