Tuesday

Estimates of cheetah numbers are ‘guesswork’, say researchers



Current estimates of the number of cheetahs in the wild are ‘guesswork’, say the authors of a new study which finds that the population in the cheetah stronghold of Maasai Mara, Kenya, is lower than previously thought.
In the early 1900s it was believed that around 100,000 cheetahs roamed the Earth. The most recent estimate by the International Union for Conservation of Nature (IUCN) puts the figure at 6,600 – mainly in eastern and southern Africa – amid fears that the fastest land mammal is racing to extinction.
However, a team of scientists from the Kenya Wildlife Trust’s Mara Cheetah Project, the University of Oxford and the Indian Statistical Institute says this number is simply a best guess, given the difficulty of counting cheetahs accurately.
The researchers have now developed a new method to accurately count cheetahs, which in time will help determine the magnitude of the threats they face and assess potential conservation interventions.
Lead author Dr Femke Broekhuis, Project Director of the Mara Cheetah Project and a post-doctoral researcher at the Wildlife Conservation Research Unit (WildCRU), Department of Zoology, University of Oxford, said: ‘The truth is that estimates of cheetah numbers are only best guesses, because cheetahs are a lot harder to count accurately than one might think. They naturally occur at low densities and move large distances, making them difficult to find.
‘Whatever the exact number, we do know that they are extinct in 20 countries and occupy only 17% of their historical range. We also know the major threats facing cheetahs: habitat loss, human-wildlife conflict, depleting prey and the illegal pet trade.
‘What we have lacked until now is a way to assess whether or not conservation efforts are effective.’
During a three-month period, researchers in five vehicles extensively covered the Maasai Mara National Reserve and surrounding wildlife conservancies in search of cheetahs. The field team photographed each cheetah that was seen and identified each individual based on its unique coat pattern. These data were then analysed using an advanced Bayesian Spatially Explicit Capture Recapture (SECR) statistical model. This technique, incorporating information such as identity and location, is more powerful than previous methods used to estimate cheetah numbers.
The study revealed an average of 1.28 adult cheetahs/100km2 in the Maasai Mara – an average total of 30 animals. This number is lower than previously thought – around half, in fact. The ‘spatially explicit’ method used can distinguish ‘visiting’ animals from those that reside permanently within the surveyed area, avoiding potential overestimation. The researchers compare this to counting the population of Manhattan in the daytime, which would give a vastly inflated figure because of the influx of commuters from neighbouring areas.
The researchers also identified clear cheetah ‘hotspots’ within the Maasai Mara. The next step is to determine how the distribution of these high-density areas is correlated with environmental variables such as habitat, prey, predators, or anthropogenic factors including livestock grazing.
The results of this study will allow threats and conservation efforts to be quantified and monitored in the future.
Dr Broekhuis said: ‘In order to determine the impact that threats and conservation efforts are having on the cheetah population, it is necessary to rigorously monitor their numbers over time. Our results are therefore important, as they provide the baseline data needed to accomplish this.
‘The relevance of this study goes beyond cheetahs in the Maasai Mara. This is the first time that this robust method has been used to estimate cheetah densities, and it is a method that can be applied to other areas and other charismatic species such as lions or even elephants.’
Co-author Dr Arjun Gopalaswamy, from the Indian Statistical Institute and the Department of Zoology at the University of Oxford, said: ‘The method we have used accounts for detection probability and is therefore more accurate than other methods that are currently being used to estimate cheetah numbers. In addition, the modelling approach we have used allows for estimating not only abundance and density, which were of prime interest to us, but also provides vital information about adult sex ratios and sex-specific home range sizes.
‘These measures provide crucial insights about big cat ecology that aids their conservation. For example, India has been considering the reintroduction of the African cheetah. Even in a prey-rich area like the Maasai Mara, the density of cheetahs is low, suggesting that the resource requirements for these cats are perhaps much larger than would be available currently in the Indian subcontinent.’
The study’s authors say there is an urgent need to rigorously assess the population size of cheetahs in all the remaining strongholds, using advanced methods such as this one. They also suggest that relying merely on best guesses of cheetah numbers at regional levels can seriously mislead cheetah conservation efforts on the ground.

Researchers meet in Tanzania, plot banana yield rise


A team of researchers from around the world are  this week, 2– 5 May 2016, gathered at the Nelson Mandela Africa Institution of Science Technology (NM-AIST) in Arusha, Tanzania, to discuss how to focus their combined expertise on improving banana, a hugely important crop in the East African Region.
The researchers—drawn from Australia, Brazil, India, Malaysia, Tanzania, Uganda, Sweden, Belgium, South Africa, and USA—are implementing a five-year project that seeks to improve the production and productivity of banana in Tanzania and Uganda. Worldwide, very few programs focus on banana breeding and this meeting brings together researchers from many of these programs.
The project aims to strengthen the banana breeding programs in Uganda and Tanzania to dramatically upscale and speed up on-going efforts to develop new high-yielding and disease-resistant hybrid varieties. It focuses on the two most popular cooking bananas in the region—East Africa Highland banana (EAHB) also known as ‘Matooke,’ and ‘Mchare’ grown in Tanzania.
Millions of smallholder farmers in Tanzania and Uganda rely on banana as a staple food and major source of income. The two countries produce over half of all banana grown in Africa with the region's yearly crop valued at $4.3 billion. However, the crop only achieves around 9% of its potential yield due to pests and diseases, posing a serious threat to the future sustainability of banana production in the region.
“The team will develop hybrid varieties with a 30% higher yield and a 50% higher resistance to at least three of the major pests and diseases compared to the current varieties grown by farmers under the same on-farm conditions. The new varieties will also meet almost all the quality traits preferred by consumers in the current varieties, says Danny Coyne, a Soil Health Specialist at the International Institute of Tropical Agriculture (ITA) and the project manager.
The diseases are Fusarium Wilt and Black Leaf Streak diseases, and pests include the burrowing nematode and weevils.
“Banana is very important in Tanzania but it is being heavily attacked by pests and diseases. With this project, we will be able to build the capacity of our research team to develop improved high-yielding hybrid varieties which our farmers need. Furthermore, through this project, we will have a better and more vibrant breeding system across East Africa that can respond to current and future challenges of the crop, especially now in the face of climate change,” says Prof Patrick Ndakidemi, Deputy Vice Chancellor, Planning, Finance and Administration and the Project Coordinator at the NM-AIST.
The project will, among others, provide training for postgraduate students and technical staff in advanced breeding techniques and facilitate the exchange of genetic material across countries and even continents.
The project is being led by IITA in close cooperation with national partners in Tanzania and Uganda. The regional breeding activities are being conducted at NM-AIST in Arusha, Tanzania, in collaboration with agriculture research institutes (ARI) in the banana-growing areas, and at the Uganda Banana Breeding Programme of the National Agricultural Research Organization (NARO) at Kawanda, and Sendusu in Kampala.
Building on past successes
Past breeding efforts by NARO, Uganda, in collaboration with IITA successfully developed the first ever hybrids of the East African Highland Banana that were named NARITA. Currently there are 27 NARITAs, two of which were formally released as new cultivars in 2010 by NARO and are so far being grown in 15% of the banana farms in Uganda.
Under this project, at least 20 of these 27 NARITAs will be tested and promoted across the region for suitability and acceptance by farmers.
“It took the team 18 years to generate these hybrids, and although they represent a significant progression from the current varieties they remain suboptimal in several respects including height, pest and disease resistance, and fruit quality traits. Our new project will build on this success and take banana breeding to the next level,” says Prof Rony Swennen, Head of the IITA Banana Breeding program and the Project Team Leader.
The project will conduct studies to understand the genetic make-up and diversity of existing varieties to identify sources of resistance to the major pests and diseases. This will be complemented by research to understand the spread and damage caused by these pests and diseases, and development and application of quick diagnostic tools and faster screening mechanisms to assess resistance.
This project will also facilitate the exchange of genetic material with breeding programs in Brazil and India, therefore establishing the foundations of a globally connected Musa breeding system. The exchange will provide this project with access to improved diploid hybrids for crossing with ‘Matooke’ and ‘Mchare’ germplasm.  
This project is being conducted within the framework of the CGIAR Research Program on Roots, Tubers and Bananas (RTB).
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