The Ecology of Dactylanthus Taylorii and Threats to Its Survival (original) (raw)
Related papers
2015
Dactylanthus taylorii is New Zealand's only fully parasitic flowering plant. It is the most southerly occurring member of the largely tropical family Balanophoraceae, and the only species in the genus. A study, funded by the Department of Conservation, of the ecology of this unusual plant has shown that the possum and the kiore pose a critical threat to its survival, eating the flowers and thus preventing seed production. The dull-coloured, bowl-shaped inflorescences appear to be for pollination by a relatively large, nocturnal animal, and contain a very large quantity of strongly scented nectar which is attractive to possums and rats. Monitoring of the flowers using a time-lapse video camera with infra-red lighting has provided convincing evidence of pollination by the short-tailed bat, Mystacina tubcrculata, also attracted to the nectar. These discoveries raised the possibility of developing a possum or bat lure from the chemicals found in the nectar.
2004
Dactylanthus taylorii is New Zealand's only fully parasitic flowering plant. It is the most southerly occurring member of the largely tropical family Balanophoraceae, and the only species in the genus. A study, funded by the Department of Conservation, of the ecology of this unusual plant has shown that the possum and the kiore pose a critical threat to its survival, eating the flowers and thus preventing seed production. The dull-coloured, bowl-shaped inflorescences appear to be for pollination by a relatively large, nocturnal animal, and contain a very large quantity of strongly scented nectar which is attractive to possums and rats. Monitoring of the flowers using a time-lapse video camera with infra-red lighting has provided convincing evidence of pollination by the short-tailed bat, Mystacina tubcrculata, also attracted to the nectar. These discoveries raised the possibility of developing a possum or bat lure from the chemicals found in the nectar.
The use of Dactylanthus nectar as a lure for possums and bats
2000
Dactylanthus taylorii is New Zealand's only fully parasitic flowering plant. It is the most southerly occurring member of the largely tropical family Balanophoraceae, and the only species in the genus. A study, funded by the Department of Conservation, of the ecology of this unusual plant has shown that the possum and the kiore pose a critical threat to its survival, eating the flowers and thus preventing seed production.
Caged for protection Exploring the paradoxes of protecting New Zealand’s Dactylanthus taylorii
Emerging from an ethnographic encounter with the conservation efforts to save an enclave of Dactylanthus taylorii in Tongariro National Park, the article discusses some of the paradoxes of conservation management by interdisciplinary tracing the research and conservation history of the plant. First, the article examines how our efforts to protect native species contribute to transforming the very environment of which they are part. Furthermore, by tracing the plant’s history of decline and the following rise of conservation, the article addresses the role of native species in relation to notions of belonging and the creation and maintenance of a national heritage. Accepted for publication in Environment and History - Hyperlink gives OPEN ACCESS to authors’ versions of papers as accepted (pre-copyediting). Cite as ‘forthcoming in Environment and History’. http://www.whpress.co.uk/EH/papers/1082.pdf
Genetic diversity of Dactylanthus taylorii in New Zealand
Randomly amplified polymorphic DNA (RAPD) markers were used to investigate genetic variation amongst 17 populations (146 individuals) of the endangered parasitic plant Dactylanthus taylorii. The objective was to provide a means of identifying a set of populations that are representative of the full range of genetic diversity within the species, towards which conservation resources might be targeted. RAPDs produced clear, reproducible bands, and 84 polymorphic marker bands were identified. Analysis of the RAPD data, based on Neis genetic distance, produced a dendrogram that grouped all individuals (bar one) into their expected populations. A similar analysis at the population level showed the grouping of populations was, to a significant extent, determined by geographical distribution. Two major clusters were evident, one containing populations close to and east of Lake Taupo, and the second consisting mainly of populations west of Lake Taupo. Little Barrier Island, the most isolated population, occupied a discrete branch within the second cluster. Further geographical ordering was evident within the major clusters, with neighbouring populations being grouped together. The populations at Little Barrier Island, Pirongia, Mamaku, and Waitaanga Forest were identified as being the most genetically distinct at the national level, and it is recommended that these are targeted for management. Overall, genetic groupings did not reflect conservancy boundaries. For this reason it is also recommended that conservancy management decisions regarding the allocation of resources to populations, or withdrawal thereof, should take into account the genetic status of those populations at the national level.
Reproductive biology of Datura wrightii: the benefits of a herbivorous pollinator
Annals of Botany, 2009
A deeper understanding of mutualism can be reached by studying systems with measurable costs and benefits. Most studies of this type focus on an unusual class of obligate, species-specific pollination mutualisms. The interaction between Datura wrightii (Solanaceae) and the hawkmoth Manduca sexta offers similar advantages but greater generality. Adult moths both nectar at and deposit eggs on the same plant; larvae are herbivorous. The antagonistic component of this interaction has been well studied. Here the role of M. sexta as a pollinator of D. wrightii, particularly in the context of this moth's frequent nectaring visits to the bat-pollinated plant Agave palmeri, is documented. † Methods Hand-pollinations were used to determine breeding system and the reproductive consequences of mixed loads of A. palmeri and D. wrightii pollen. Plants and moths were caged overnight to assess whether nectaring visits led to fruit and seed set. Finally, pollen deposited on field-collected stigmas was identified, with a particular focus on documenting the presence of D. wrightii and A. palmeri grains. † Key Results Datura wrightii is highly self-compatible, and a visit that deposits either outcross or self pollen almost doubles fruit and seed set compared with unvisited flowers. Manduca sexta transferred enough pollen to produce fruit and seed sets comparable to hand-pollination treatments. Agave palmeri did not interfere with D. wrightii success: in the field, stigmas received almost pure D. wrightii pollen, and hand-addition of large quantities of A. palmeri pollen had no measurable effect on fruit and seed set. † Conclusions The floral visitation component of the D. wrightii -M. sexta interaction is indeed mutualistic. This finding is essential background to future development of this interaction as a model system for studying mutualism's costs and benefits. It is already proving valuable for dissecting third-species effects on the outcome of mutualism. Results indicate that M. sexta's heavy visitation to A. palmeri has no negative effect on the benefits conferred to D. wrightii. However, it can be predicted to augment M. sexta populations to the point where the costs of the interaction begin to exceed its benefits.
Location of short-tailed bats using Dactylanthus
1994
Eight Dactylanthus sites in Tongariro/Taupo Conservancy were monitored for short-tailed bats while the plants were in flower in 1993 and 1994 but no definite recordings of bats were made at any of these sites. Video and bat detectors linked to tape recorders were used for the monitoring and while both systems were successfully used to locate bats at Pureora and Ohakune the bat detector is recommended for general use because it is much more portable, less expensive and easier to operate. Two new Dactylanthus sites were located and one is considered a possible site for short-tailed bats and should be monitored for bats when the plants are in flower. PURPOSE: To provide information on the location of the endangered short-tailed bat in the central North Island so that the species can be managed in an effort to prevent its extinction in the region.
ANT POLLINATION OF DACTYLORHIZA VIRIDIS
Dactylorhiza viridis is generally pollinated by Coleoptera (beetles) and Hymenoptera (sawflies, wasps, bees, and ants). This orchid offers nectar at the lip base as well as in the spur. In the Dolomites, a calcareous mountain region in Italy, we found reasonable numbers of Dact. viridis, all growing in the vicinity of nests of the ant Formica (Coptoformica) exsecta. The ants had discovered the nectar of the orchid as a supplemental food source and acted as pollinators of Dact. viridis, carrying, on average , three pollinaria on their head. Their repeated visits led to a high degree of geitonogamy. This is the first mention of ant pollination of Dact. viridis.