CABI scientists have revealed the massive ecological and economic impacts that the invasive alien tree Prosopis juliflora has had across the Afar Region of north eastern Ethiopia.
Dr Urs Schaffner, who is supervising lead author Mr Hailu Shiferaw for his PhD studies, contributed to the Science of The Total Environment published research which shows that the devastating Prosopis was a major reason for losses in annual ecosystem service values in Afar Region estimated at US $602 million in just 31 years.
The start of 2019 brought sad news when George, the last tree snail of his kind (Achatinella apexfulva) died on New Years Day. His death highlights the plight of Hawaiian snails and epitomises the rapid decline of biodiversity on the Hawaiian Islands.
For many, December means celebrating Christmas and a central part of that is a Christmas tree. Evergreen trees have been used in celebration for centuries. The ancient Egyptians, Chinese, and Hebrews used evergreen trees, wreaths, and garlands to symbolize eternal life. Pagans worshiped trees, and Romans used evergreen wreaths during the festival of Saturnalia.
The trees commonly used as Christmas decorations come from the genus Picea which is made up of around 35 species of coniferous evergreen trees in the family Picaceae. Popular Christmas tree species include Balsam Fir, Douglas Fir, and Norway Spruce.
The modern-day Christmas tree is thought to have started in 16th century Germany when Christians brought decorated trees into their homes. The Christmas traditions we know today were shaped by the Victorians, when the first Christmas tree was brought from Germany to the British royal household by Prince Albert in the 1840s. These days, around 7 million real trees are sold each year in the UK, and as many as 30 million in the USA.
Called the “White Forest” by native populations, the Caatinga ecosystem covers an estimated 11% of Brazil and is spread across the states of Alagoas, Bahia, Ceará, northern Minas Gerais, Maranhão Paraíba, Piau, Pernambuco, Rio Grande do Norte and Sergipe. This dry forest is home to the largest populations of Carnaúba palms in the world. It also has some of the world’s most diverse plant life and its biodiversity is critically important to maintaining the variety of animals native to the region, such as the emblematic three-banded armadillo.
After habitat destruction, invasive alien species are the second biggest threat to biodiversity worldwide. It has a significant impact on livelihoods and the economy, incurring losses of USD$1.4 trillion a year. Prior to 2012 many South-East Asian countries lacked the policies and information on the presence, distribution and impact of invasive species to properly manage this increasingly urgent threat. Continue reading →
The Global Forum on Agricultural Research (GFAR) posted four blogs about CABI’s activities in its ‘Partner Spotlight’ feature. One of these was on a four-year Global Environment Facility (GEF) funded project that we led which ended recently. The FORIS project was about preserving important genetic diversity in some of SE Asia’s forests. The blog is re-posted here.
Mikania (Mikania micrantha) is a tropical vine which is native to the Americas. Often referred to as the ‘Mile-a-Minute Weed,’ mikania grows rapidly in areas of high rainfall and has become highly invasive in parts of Asia and the Pacific. Under the Convention on Biological Diversity, invasive species are defined as alien species that threaten native ecosystems, habitats or species and in Nepal, mikania and other invasive plants such as chromolaena (Chromolaena odorata) are becoming increasingly problematic within the Chitwan National Park (CNP). There, the plants are having a serious negative impact on native grasses, shrubs and the one-horned rhinoceros, and by implication, deer and tiger populations. They are also affecting the local people who reside in the buffer zones and rely on the park for fodder and other materials.
In a specific study on mikania, scientists from the National Trust for Nature Conservation, Nepal with support from CABI and the Zoological Society of London have found a significant negative relationship between high mikania coverage and the population of rhinos. This is because the mikania vine smothers the fodder plants that the rhinos feed on. This could also be influencing their movement to other areas of the park where they feed on resources and crops important to local people. This in turn may exacerbate conflict between the residents of the buffer zones and the wildlife in the area.
Deer and Tigers
The reduction in fodder plants is likely also to cause a mirrored decrease in the number of deer in the park. Deer feed on similar plants to the rhinos and the impact of mikania on native vegetation is therefore likely to affect their feeding behaviour in a comparable manner. As a result a decrease in deer numbers is likely to have a negative impact on tiger populations, with tiger numbers being directly related to the populations of their prey.
The residents of the buffer zones surrounding the CNP are known to rely on the core area of the park for resources such as fodder, which they use to feed their livestock. These residents recognise that fodder availability within the park has decreased and report that collecting materials now takes three times as long as it has in previous years to gather the same amount of fodder. Reduced fodder has been attributed to flooding of the park and the spread of invasive plant species. In particular, a high proportion of local residents report that mikania has a significant negative impact on the fodder growing in the park.
Sustainable control of mikania weed
CABI piloted using a rust fungus (Puccinia spegazzinii) as a classical biological control agent for mikania weed in India. This highly host specific and damaging pathogen has now been released in Papua New Guinea and Taiwan, where it is having a significant impact on the growth of the weed. The rust has recently been released on a number of other Pacific Islands, and could be considered for release in Nepal.