Tag Archives: Conservation

The birds and the bees in Hawaii: New study explore the effects of non-natives on ecosystem functioning

The more recent concept of monitoring restoration through ecosystem functioning has received support from scientists, but little practical study. New research by Hanna et al. (2012) studies the effects of invasive wasp species on plant pollination and fruiting in Hawaii.

Metrosideros polymorpha is an endemic flowering tree, historically pollinated by honeycreeper birds and bees. Honeycreepeer populations became threatened by predation from invasive spoecies, habitat degradation, competition and disease, causing population declines and extinctions. Following the decline of honeycreepers, and invasion of wasp species, Vespula pensylvanica, and introduction of the western honey bee, Apis mellifera, the non-native species began feeding on the nectar stores of M. polymorpha. V. pensylvanica is a non-pollinating insect; it reduces nectar availability to other wasps by defending a flower, where it stays, drinking the nectar and chasing away or hunting and eating pollinating bees. This reduces the plants fruiting success, as the wasp reduces the nectar supplies M. polymorpha produces to attract pollinators, and directly repels other insects, preventing pollination. A. mellifera, however, is known to pollinate some plants, though only those whose flower shape enables pollination transfer from the small honey bee.

Hanna et al. experimentally removed V. pensylvanica from selected sites, and recorded the effects on pollinaters and fruiting success. Visitation by pollinating insects increased, likely as predation risk decreased and nectar more available, which led to increased fruiting success. Both A. mellifera and endemic Hylaeus began visiting the flowers more often, but Hanna et al. believe they had differing effects on fruiting success. As A. mellifera visited more frequently, it would appear that they are more responsible for the increased fruiting success than Hylaeus, whose visitation rates increased less. A. mellifera could be acting as replacement pollinators following the drop in honeycreeper numbers, helping to sustain plant fruiting. Though this effect is postive for M. polymorpha, an increase in A. mellifera could increase competition with other pollinators, and may not be an effective pollinator of all plant species from which it takes nectar, especially ones which attract a less diverse range of pollinators.

This study emphasises the need to assess how species alter ecosystem functioning when forming management plans, and highlights the variability of impacts of invasive species. Hanna et al. suggest the next steps taken should be to assess wider effects of A. mellifera, and how V. penslyvanica affects pollination at different times of the season.

Hanna, C., Foote, D., Kremen, C. (2012), Invasive species management restores a plant–pollinator mutualism in Hawaii. Journal of Applied Ecology.


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Modern Fishing: using science to set tuna quota regulations

For decades overfishing has been a major concern, but new tuna quotas utilise scientists’ recommendations to achieve a sustainable fishing effort. Despite recent tuna increases, The International Commission for the Conservation of Atlantic Tunas (ICCAT), who set tuna fishing regulations, decided to set only a small increase in tuna fishing quotas, to allow population recovery.

Many tuna species have shown decreased populations as a direct result of overfishing, such as the bluefin tuna, which fell by 60% between 1997 and 2007. These declines, their high market demand, and the negative effects of tuna fishing on other species were cause for quota implementation. Recent evidence suggests a rebounding of tuna populations, but scientists warn that caution must be used when adjusting regulations, due to their still low numbers and fragile state. Concern over the long-term sustainability of conservation action has been previously raised, with scientists stressing the need to allow recovery from depleted states even when populations are increasing.

With pressure exerted on regulatory bodies by fisheries, the proper use of science when setting fishing limits has often been previously ignored. The relatively low increase in ICCAT 2013 quotas, however, helps break this trend by including science in policy-making. Such action helps guide the way towards more informed and sustainable marine use.

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Silent Spring celebrates its 50th anniversary

In contrast to the care-free, all-loving vibe often associated with the Sixties, Silent Spring stood as a confrontational and alarming reality hit of the choking effects of industry on nature. This year marks the 50th anniversary of Carson’s Silent Spring, which has been described as ‘one of the most important books in ecology’ and helped bring environmental issues into the public eye at a time when awareness was low but destruction high.

Silent Spring focuses on the disastrous effects of pesticides on the environment. The title alludes to the detrimental effects of chemicals such as DDT on animals – in particular birds – due to bioaccumulation and unforeseen side-effects.

Carson became interested in the release of such chemicals into the environment as early as the 1940’s, but states that the impetus for the book came from a letter in a local newspaper, reporting numerous bird deaths following a DDT spraying. It was this, along with Carson’s background as a marine biologist and experience as a published author that led to the writing of Silent Spring.

Seen by many as a subversive and damaging notion, the message delivered by Carson’s account was met with threats of lawsuits and accusations of exaggeration. Her claims sparked an investigation by then-US President Kennedy, which led to the tightening of pesticide regulations and a surge in public interest in pollution and environmental protection.

Today, Silent Spring stands as a prominent historical publication for conservationists. Carson’s writing is direct and steadfast, yet accessible, helping inspire mass environmental movement against issues once controversial and little-known.

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Red Panda (Ailurus fulgens) relocated for UK Captive Breeding Programme

Pichu, a female red panda (Ailurus fulgens) at a conservation park in southern Scotland, is set to be part of captive breeding efforts following the introduction of a new possible mate. Ruben, a young male, has been relocated from Paignton Zoo in Devon, to accompany the previously alone Pichu at Galloway Wildlife Conservation Park.

Breeding programmes are an important part of conservation planning for species with low population numbers, such as the red panda of which less than 10,000 adults are believed to exist. This allows scientists to monitor population growth and breeding behaviour, as well as protecting vulnerable mothers and young. Captive breeding programmes have been successful in protecting a wide variety of species from extinction, the Arabian oryx (Oryx leucoryx) and Przewalski’s horse (Equus ferus przewalskii) have been reintroduced to the wild as a result. But they are not without their challenges. The giant panda (Ailuropoda melanoleuca) is famous for its apparent loss of interest in breeding once captured; whilst organisations such as the European Endangered Species Programme (EEP) must manage inbreeding problems and sustain genetic diversity.

Red Panda, Ailurus fulgens – Brunswyk

Endemic to the Himalayas, red panda populations began to decline as a result of deforestation and harvesting for fur. Livestock trample the bamboo on which red pandas feed, and as human development spreads, panda populations become increasingly isolated. Overall, a decline of ~40% has been estimated for populations in China over the past 50 years. The IUCN has listed red pandas as vulnerable, and trading has been banned by CITES. Although protected in all of its range, conservation efforts vary: population estimates are unavailable for Burma and Bhutan where they have been known to be confused with civets, and poaching still occurs.

Red pandas have shown adaptability to living in captivity, where ~800 individuals are currently held. Breeding rates are high across many zoos, the Padmaja Naidu Himalayan Zoological Park (Darjeeling, India) has successfully released four captive bred pandas to the wild, whilst many more have been born in captivity.

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May 29, 2012 · 1:08 pm