Mar 29
St Helena gumwood image

St Helena gumwood (Commidendrum robustum)

Species: St Helena gumwood (Commidendrum robustum)

Status: Endangered (EN)

Interesting Fact: In 1977, the St Helena gumwood was adopted as the national tree of St Helena, a UK Overseas Territory.

As its name suggests, the St Helena gumwood is endemic to the small volcanic island of St Helena in the South Atlantic Ocean. This highly branched tree has a crooked, knarled trunk, an umbrella-like canopy and thick, hairy, wrinkled leaves. During the winter and spring, the St Helena gumwood produces white flowers which droop from the ends of the branches. This hermaphroditic plant was once a regularly occurring species within subtropical and tropical forests on inland cliffs and mountain peaks, with large amounts of seed falling around the parent plant and germinating freely.

Since 1659 when the first settlers arrived on St Helena, the St Helena gumwood has been exploited for use as timber and firewood, and forests have been cleared to make way for pastureland. In addition, this species faced further pressure from introduced goats which grazed heavily on its seedlings. By the 1980s, the St Helena gumwood population had been drastically reduced, and this spurred conservationists to put a management plan into action.

This species is now protected by the Endangered Endemic and Indigenous Species Protection Ordinance 7 of 1996, and the instigation of the Millennium Gumwood Forest Project resulted in 4,300 St Helena gumwood trees being planted in previously degraded wasteland in 2000. Other replanting and weed clearance projects are underway, and a successful biological control programme has helped to combat the destructive jacaranda bug which was responsible for a decline in the St Helena gumwood population in the early 1990s.

 

Find out more about environmental management on St Helena.

See images of the St Helena gumwood on ARKive.

Kathryn Pintus, ARKive Content and Outreach Officer

Dec 7
Photo of jellyfish tree flowers

Jellyfish tree (Medusagyne oppositifolia)

 

Species: Jellyfish tree (Medusagyne oppositifolia)

Status: Critically Endangered (CR)

Interesting Fact: The flowers of the jellyfish tree have numerous stamens, and it is thought that these may have given rise to the name of Medusagyne, after the ‘Medusa’ of Greek mythology who had a head of snakes.

 

More information:

The jellyfish tree was thought to be extinct until the 1970s, when a few trees were found, but the species still teeters on the brink of extinction. Jellyfish trees can reach up to 10 metres tall and have a dense, rounded crown of foliage. The shiny, leathery leaves have a slightly scalloped edge and turn bright red with age. The jellyfish tree is the only species in its family.

Found on the island of Mahé in the Seychelles archipelago, only approximately 50 jellyfish trees are known, surviving within 4 separate populations. Jellyfish tree seeds appear to be unable to germinate in the wild, and it is thought that trees of this species have been lost from more appropriate humid forest habitats as a result of competition and climate change. They have been successfully cultivated in botanic gardens in very humid conditions.

Three of the existing populations of jellyfish tree on the island of Mahé are protected within the Morne Seychellois National Park. Although seedlings have been grown in a number of botanic gardens, many problems remain for this species, and a conservation priority must be further research into its reproductive biology so that an effective action plan for its future can be devised.

 

Find out more about the jellyfish tree at the Eden Project and Saving Paradise.

See images of the jellyfish tree on ARKive.

Phoebe Shaw Stewart, ARKive Text Author

 

Nov 28

The observance of Thanksgiving Day is primarily associated with the United States, and is a tradition which is thought to date back to colonial times following the safe arrival of the first European settlers to the untamed shores of North America. Nowadays, families and friends congregate to give thanks for what they have, so to celebrate Thanksgiving in our own wild way, we’ve gathered together a few of nature’s special inhabitants that we think owe each other thanks: symbiotic species!

 

Exclusive residence

Common clownfish image

Common clownfish are able to live among the tentacles of stinging sea anemones

Simply speaking, symbiotic species are those that interact in some way, to the benefit of one or both of the critters in question. A classic example, and one that many Disney fans will be familiar with, is the relationship that exists between clownfish and sea anemones.

Sea anemones usually sting fish that come into contact with their tentacles, but clownfish have developed a clever, yet rather gross, method of disguise. By covering its skin in mucus, the clownfish can trick the anemone into thinking it is touching itself, and so does not get stung. In return for a safe place to live and food in the form of debris and parasites found amongst the anemone’s tentacles, the clownfish is thought to scare away fish that may prey upon the anemone, and even lure fish in for its tentacled home to eat – a classic win-win situation! The clownfish is also believed to provide the anemone with good water circulation through fanning its fins as it swims around.

Did you know?

There are different kinds of symbiotic relationships. Some benefit both species involved, and are known as ‘mutualistic’ symbioses, whereas ‘parasitic’ relationships are those in which one species profits at the expense of the other. In some cases, one species benefits but the other is affected neither positively nor negatively, and these are known as ‘commensalistic’ symbioses.

 

Nutritious nectar and pollen parcels

Small garden bumblebee image

Bees, such as this small garden bumblebee, play an important role in plant pollination

Bees feed on pollen and nectar sourced from a variety of flowering plants, with honey bees using the nectar to make their sticky, sugary treat. Although flowers appear to lose out by ‘donating’ nectar, they actually benefit from these flying visits. As a bee rummages around the flower head for food, some pollen gets stuck to its hairy body and legs, and this accidental cargo is then transferred to the next flower the insect visits, pollinating it and enabling the plant to reproduce.

Did you know?

The traditional origin of the modern Thanksgiving Day is commonly thought to be the festivities that occurred at the Plymouth Plantation in Massachusetts in 1621, when the European settlers celebrated their safe voyage, peace and good harvest. However, there is some evidence to suggest that Spaniards in Florida were the first to truly celebrate Thanksgiving back in 1565.

 

Getting a little peckish…

Roan antelope image

Oxpeckers help remove parasites from large mammals such as this roan antelope

In the wilds of the African savanna, large mammals such as this roan antelope can quickly become covered in ticks and all sorts of other creepy crawlies, which doesn’t sound entirely pleasant! Luckily, help is at hand in the form of winged wonders known as oxpeckers. Oxpeckers are known to hitch a ride on the backs of a range of iconic species including hippos, buffalos, giraffe and various antelopes, gorging themselves on ticks, botfly larvae and other parasites – the mammals get cleaned, and the birds get fed, and so this has often been classified as a mutualistic relationship. However, more recent studies have shown that oxpeckers often pick at scabs and cuts to keep them open to get more food, subjecting the wounds to possible infection and potentially harming the host mammal, making this symbiotic relationship more of a parasitic one.

 

Helpful houseguests

Acropora formosa image

Reef-building corals rely on tiny blue-green algae to survive

Reef-building corals provide homes for single-celled blue-green algae known as zooxanthellae, and in return these microscopic plants provide energy-containing compounds for the coral through the process of photosynthesis. The coral uses these vital compounds to build its calcium carbonate skeleton. In a way, these tiny blue-green algae are like live-in coral chefs…and they even clean up after themselves by removing any waste products! Brilliant!

 

Nature’s six-legged gardeners

Leaf-cutter ant image

Leaf-cutter ants tend to their fungus garden by creating ‘mulch’ from leaf fragments

Leaf-cutter ants are known as nature’s gardeners, as they spend their time foraging for leaves and cutting them into suitably sized fragments before transporting them back to their huge underground nests where the leaves are used to cultivate a fungus garden. While the ant colony is entirely dependent upon this fungus supply for food and so greatly benefits from this situation, the fungus benefits by being cultivated by the ants but also loses out by being eaten, and so this relationship could be classified as a more commensalistic one.

Did you know?

Most of us think of the US in relation to Thanksgiving, but did you know that several other countries observe similar days, too? These include Canada, Puerto Rico and Liberia. Additionally, the city of Leiden in South Holland celebrates the traditional US Thanksgiving Day, making the Netherlands the only non English-speaking country to formally celebrate this particular occasion.

 

Food on the go…

Dugong image

Dugong

Loggerhead turtle image

Loggerhead turtle

 

 

 

 

 

 

 

 

Leopard shark image

Leopard shark

Giant manta ray image

Giant manta ray

 

 

 

 

 

 

 

 

Scientists are somewhat divided over whether the relationship that exists between specialised fish known as remoras and a variety of larger ocean species is a mutualistic or commensalistic one. Also known as suckerfish, remoras have a specially adapted first dorsal fin which has been modified into a sucker-like organ. Remoras use this to attach themselves to other marine animals such as sharks, rays, sea turtles and dugongs, feeding on material dropped by the host species while also getting a free ride and protection from potential predators. This seems rather one-sided, but some scientists believe that the remoras may also feed upon certain parasites on the host’s body or gills, therefore providing a great cleaning service to their marine meal providers.

If these beholden bovids, indebted invertebrates and contented chondrichthyans haven’t quenched your thirst for wild Thanksgiving-related information, why not check out last year’s blog, which features a whole host of awesome animals that the first European settlers might have seen upon arriving in North America.

Happy Thanksgiving!

 

Kathryn Pintus, ARKive Text Author

 

Oct 12
Photo of Maltese rock-centaury flowers in habitat

Maltese rock-centaury (Cheirolophus crassifolius)

Species: Maltese rock-centaury (Cheirolophus crassifolius)

Status: Critically Endangered (CR)

Interesting Fact: The Maltese rock-centaury is the national plant of Malta.

More information:

A perennial plant with smooth, fleshy leaves and attractive purple flowers, the Maltese rock-centaury is found on Malta and the nearby islands of Gozo and Fungus Rock. It grows only in full sun on coastal limestone cliffs and on loose rock debris on slopes. This long-lived plant flowers between May and July, producing a single flower head on each flowering stalk. The flower heads of the Maltese rock-centaury are made up of many small, individual, tubular flowers and are surrounded by a whorl of specialised leaves, or ‘bracts’, with the whole structure resembling a single flower. The seeds of the Maltese rock-centaury are dispersed by the wind.

The Maltese rock-centaury has a very restricted range, being found in a total area of less than 100 square kilometres. Its population is fragmented and is estimated at just a few thousand individuals. The main threats to this plant include nearby quarrying activities, which can cause the fragile cliffs it grows on to collapse, and human disturbance in more accessible areas. Invasive plants also pose a risk, while an unidentified moth larva has been seen attacking this species’ developing fruits. The Maltese rock-centaury is listed on the EC Habitats Directive as a priority species, giving it legal protection, and some of the cliffs it grows on are also protected. This plant has also been cultivated, providing potential stock for future reintroductions. The Maltese rock-centaury’s habitat requires careful management and protection, and better control of quarrying and of invasive plants is also needed.

 

Find out more about the Maltese rock-centaury and other threatened Mediterranean plants at IUCN – The Top 50 Mediterranean Island Plants: Wild plants on the brink of extinction, and what is needed to save them.

See more images of the Maltese rock-centaury on ARKive.

Liz Shaw, ARKive Text Author

Aug 3
Photo of Wollemi pine leaves

Wollemi pine (Wollemia nobilis)

Species: Wollemi pine (Wollemia nobilis)

Status: Critically Endangered (CR)

Interesting Fact: The Wollemi pine is the only surviving member of an ancient group of plants that dates back to the time of the dinosaurs.

More information: An ancient and unusual tree, the Wollemi pine was thought to have been extinct for two million years before it was found growing in a remote gorge in Wollemi National Park, Australia, in 1994. This tall conifer produces both male and female cones on the same plant, with the female cones occurring on the higher branches and producing small, brown, papery seeds which are dispersed by the wind. The Wollemi pine can also reproduce vegetatively, resulting in numerous trunks arising from a single tree. Individuals of this long-lived species may potentially reach 500 to 1,000 years old.

The Wollemi pine has an extremely limited distribution, and fewer than 100 mature individuals now remain in the wild. The species may have been undergoing a slow, natural decline for thousands of years, but it is now under threat from fire, exotic weeds, disease, and any trampling or disturbance by unauthorised visitors. Changing rainfall and temperature patterns associated with climate change may also be a potential threat. Fortunately, this unique conifer is legally protected and a recovery plan is in place to outline management measures. In addition, access to the site where it occurs is restricted. The Wollemi pine is now being grown commercially and the plants distributed worldwide in an effort to protect the wild individuals from collectors and to generate income for this species’ continued conservation.

 

Find out more about the Wollemi pine at The Wollemi Pine and The Royal Botanic Gardens & Domain Trust – Wollemi pine.

See more images of the Wollemi pine on ARKive.

Liz Shaw, ARKive Text Author

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