The survey project:

  Surveying Hoya and its sister genera in PNG

My deaf guide showed me around in his primary forest surrounding his remote village in Morobe Province.

Often you have to look behind the tree trunks to find the hoyas

Me documentating some plants by photographing close up.

Documentating the collections of the day.

Michele Rodda making an illustration of a new species.


Since there is no publication at all dealing with the vulnerability in Hoya and sister genera anywhere in its entire distribution range, and only a little is known about PNG's species, extensive fieldwork is needed to collect specimens for further research that will reveal a lot of new data.

This survey is first of its kind, and is expected to contribute a great deal of scientific data on e.g.:

- Hoya's phylogenetic tree
- genetical relationships between closely allied genera
- specitation and distribution
- rate of endemicity for New Guinea
- reasons behind the vulnerability
- species likely vulnerable to global warming
- conservational status for each species

This survey will keep a big number of living material in cultivation in PNG, to facilitate access to fresh research material. This collection also acts like an ex situ conservation site, for vulnerable species with very limited distribution ranges.

After the end of survey, the living material may be utilized for re-colonization in protected areas.

How will the survey be conducted?

I am collecting specimens all over PNG, from sea level up to 3000 metres above sea level.

This involves exhausting trekkings inside the wonderful majestic but also almost impenetrable primary forests, full of huge tree roots to climb over, and mud slides to slide down to get anywhere, hords of stubborn malarial mosquitoes seeking for blood, and the leeches. Sometimes it means I stay for weeks inside the forests with the most unimaginable creatures that only exists here.

I usually have local guides accompanying me. They are often deaf people who want to prove that they can be guides just well as hearing people. Deaf's visual perception is usually more sharp to replace their hearing, making them able to see details quicker and spot the hoyas more easily among thousands of green leaves.

At least three or four populations are collected from each species if possible, for genetical variation and to check the intraspecific variation.

The montane species are cultivated at a level of 1500 metres above sea level in Eastern Highlands province for the montane species. The lowland species are grown at 50-250 metres above sea level in the outskirts of Lae town in Morobe Province. They are grown outdoors under shade cloth, receiving rain, allowing them to manage themselves apart from occassional need of irrigation during dry spells.

The cuttings are planted in blocks of EpiWeb (WWW.EPIWEB.SE), a plastic growing medium replacing the similar organic substrate Dicksonia/Xaxim derived from tree ferns which are endangered. Dusk Tropic contributed to the project by reducing the price greatly.

The survey is estimated to complete in five years, if I find all fundings needed. The initial three years are the most intense with many long trips and treks. Thereafter, I begin to analyze the collected specimens and data, while they please to flower in the collection site, and finishes when all specimens have flowered.

All specimens must flower, to be able to compare different populations of one single species. Then we can evaluate the intraspecific variations and the boundaries between different species which is fundamental prior to a revision of PNG's hoyas.

There are numerous species complexes in PNG where the specimens are morphologically difficult to discriminate specieswise, as many specimens overlap each other. Genetical (molecular) analyzes may be an important tool to understand these complexes.

Analyzes, in particular the molecular, are made in collaboration with eg. Michele Rodda (University of Turin, Italy) and Livia Wanntorp (Swedish Museum of Natural History, Sweden).


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