Tuesday, December 28, 2010

Manglietia cf. yuyuanensis

In a hiking trip in late June 2010, an atypical Manglietia species was found in a montane valley. We quickly recognized that it was not Manglietia fordiana, the only Manglietia species recorded in Hong Kong, as it has much smaller flowers than M. fordiana. It was thought to be another "taxon" no matter what taxonomic difference it refers to.

Magnoliaceae is indeed very well documented in China as they have very high ornamental and cultural value in the country. In the book "Magnolias of China", several small-flowered Manglietia were identified but the species matches only one of them, Manglietia yuyuanensis, which also has a geographic range close to Hong Kong. However, different taxonomists have different opinions on whether Manglietia yuyuanensis should be included in Manglietia fordiana. However, besides the morphological difference, we also noticed there is a difference of their flowering time which makes natural inter-breeding very unlikely to happen. Possibility of natural inter-breeding is conventionally an important criteria in taxonomy so this supports that they are at least of subspecies or variety level difference rather than a simple inclusion.

Yesterday we managed to make another trip to the valley to search for fruits but none was found. However, it is still exciting as more individuals were found. Many of them were adult tree but sapling or seedling were absent, suggesting that its regeneration is poor.

Thursday, December 23, 2010

Black Rhinoceros

There are currently five extant species of Rhinoceros in the world. White Rhinoceros and Black Rhinoceros are recognized as African Rhinos while Indian Rhinoceros (or Greater One-horned Rhinoceros), Javan Rhinoceros and Sumatran Rhinoceros are the Asian Rhinos. Among them, Black, Javan and Sumatran Rhinos are categorised as critically endangered according to the IUCN Redlist. Javan Rhino is particularly rare, maybe one of the rarest animals in the world, that less than a hundred is left on the planet. There are two disjunct populations of them in which 28-56 individuals are estimated in Ujung Kulon National Park, Java, Indonesia and no more than 8 individuals in Cat Tien National Park, Vietnam (WWF, 2010).

The species shown here is Black Rhinoceros (Diceros bicornis) taken in Masai Mara national park, Kenya in 2009. The reserve together with the neighbouring Serengeti national park form one of the major unfenced areas for the Rhinoceros to live in. A recent study conducted a census by aerial reconnaissance surveys and estimated that there are about 461 individuals in these two nature reserves (Metzger et al., 2007). As a whole, IUCN SSC African Rhino Specialist Group (2008) estimated that there are a total of 4180 wild individuals in 2007 and the population trend is kept increasing.

Black Rhinoceros has once been very abundant but its number dropped drastically between 1970 and 1992 by 96% due to illegal hunting (WWF, 2010)! Demands from Middle East for ornamental uses and Asian countries for traditional medicines are the major threats to the species (that is also why the Asian Rhinos are particularly endangered). Warfare among the African countries makes its conservation difficult too.

Black Rhinoceros are indeed very susceptible to poaching as they are not only huge, but also due to their preference on habitats. They mainly inhabit and forage in grasslands and savannas which normally do not hide themselves in forests or other kind of shelters. They sometimes form group of up to 12 individuals which makes them easy to be killed off too.

I was lucky enough to see a mother with her calf wandering in the savanna in Masai Mara national park. Though I was so excited of seeing these rare magnificent animals in the wild, I was so worried of their fate in the meantime as illegal poaching is still serious in Africa.

"How are they?" I am thinking.

Good luck!

IUCN SSC African Rhino Specialist Group. 2008. Diceros bicornis. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. <http://www.iucnredlist.org/>. Downloaded on 23 December 2010.
Metzger, K.L., A.R.E. Sinclair, K.L.I. Campbell, R. Hilborn, J.G.C. Hopcraft, S.A.R. Mduma and R.M. Reich. 2007. Using historical data to establish baselines for conservation: The black rhinoceros (Diceros bicornis) of the Serengeti as a case study. Biological Conservation 139: 358-374.
WWF. 2010. Rhinoceros. Available at <http://wwf.panda.org/what_we_do/endangered_species/rhinoceros/> Accessed on 23rd December 2010.

Thursday, December 16, 2010

Balanophora fungosa

Genus Balanophora is belonging to angiosperms (flowering plants) though it is always misidentified as some kinds of fungi by hikers. Though it resembles fungi by appearance but you could find floral structures in Balanophora such as its staminate and pistillate flowers and bracts by close observation. Also, fungi is saprophytic while Balanophora is obligate parasitic with specific hosts.

The specimen shown here is Balanophora fungosa taken in Queensland in late Oct, 2010. It actually has a wide distribution which is ranged from Northeastern Australia, Pacific Islands, East Malaysia, India, Taiwan and South Japan. It was reported having various hosts including Macaranga tanarius and Diospyros philippensis etc (Hsiao et al., 2010). It has monoecious inflorescence where pistillate flowers are on the upper part of the inflorescence while staminate flowers are on the lower part. There is also a wide range of floral color where the populations from Taiwan and Japan are pinkish orange while those in Queensland are yellow, as shown in the photographs here. Though it is considered as rare and vulnerable in Taiwan but it was found very abundant on the forest ground in Queensland, maybe due to different climate and host availability.

Hsiao, S., W. Huang and L. Maw-Sun (2010). Genetic diversity of
Balanophora fungosa and its conservation in Taiwan. Botanical Studies 51: 217-222.

Tuesday, December 7, 2010

Early Morning anthesis

Flowers of Thysanotus chinensis (Liliaceae) open fully between around 7 am and 9 am. It was listed as rare in previous biodiversity survey.

Early morning anthesis is a common phenomenon scattered through angiosperms. Flowers of the early morning anthesis species open in early morning, probably soon after dawn and close before or around mid-day. It is suggested to prevent heat stress as anther and stigma would be destroyed by over-heating and closure of flowers would also reduce transpiration. These are reasonable explainations as most of the early morning anthesis species are herbaceous, grassland inhabitants.

It is important to note that early morning anthesis should be more related to the pollinator activity where it is the ultimate goal of floral anthesis. After a quick search on the literatures, bees were reported to be the major pollinators of early morning anthesis species including Pyrrhopappus carolinianus (Asteraceae) (Estes and Thorp, 1975) and Cassia fasciculata (Caesalpiniaceae) (Thorp and Estes, 1975). Bees were reported to forage actively for the pollen after dawn and their activities quickly reduced towards the mid-day. The close relationship between pollinator activity and timing of anthesis is interesting and I think the early morning thesis species in Hong Kong are also pollinated by bees as certain groups of them are particularly active in the morning. There is a number of candidates for observation including the ones shown here, namely Geissapis cristata (Fabaceae), Thysanotus chinensis (Liliaceae) and Xyris pauciflora (Xyridaceae).

Geissapis cristata (Fabaceae) is another rare species in Hong Kong which inhabits lowland wetland.

Xyris pauciflora (Xyridaceae) is commonly found near wet places in Hong Kong. All of the species listed here are having brightly-colored corolla. It is an important feature to send visual signal to pollinators and to offer them a landing place.

Estes J.R. and Thorp R.W. (1975) Pollination Ecology of Pyrrhopappus carolinianus (Compositae). American Journal of Botany 62: 148-159.
Thorp R.W. and Estes J.R. (1975) Intrafloral behavior of bees on flowers of Cassia fasciculata. Journal of the Kansas Entomological Society 48: 175-184.