Although published as an Early View article last month, our paper has now been published as part of the December issue of Ecology and Evolution - and our guppies made the front cover! See the previous blog post for more info.... |
0 Comments
Detecting the impact of recreational use on Trinidad’s freshwater streams
Our latest paper, published this week in the journal Ecology and Evolution, describes how we detected the ‘signature’ of disturbance on tropical freshwater fish communities, using the streams of Trinidad’s Northern Range as a model system. “Liming” is a popular pastime on the Caribbean islands of Trinidad & Tobago. It describes the act of relaxing with friends and family – usually accompanied by food, drink and loud music. The island’s many picturesque streams are favourite locations for liming. Although it is a positive thing that people are enjoying and connecting with the natural environment, it also means that certain stretches of river are exposed to very high levels of recreational use. In this study we sampled 8 pairs of sites in the Northern Range of Trinidad, multiple times over a 2 year period; each matched pair of sites consisted of one well-known liming spot and a nearby, less-disturbed, site. This post originally appeared on my research group's website.
Every year, the El Socorro Centre for Wildlife Conservation design and present an outreach exhibit at a science fair in Point Fortin, near the south-westerly tip of Trinidad. This year the theme was to be the wildlife of Matura, with an emphasis on the freshwater fish, so the Centre’s founder, Ricardo Meade, asked me to assist. I was more than happy to get involved, and while Ricardo and his team had the hard task of constructing tanks and catching fish, I set to work illustrating and researching the various species to compile a set of educational posters and labels to accompany the display. This wasn’t hard as most of the species were those that we commonly come across on our BioTIME surveys. Thursday 22nd May was the International Day for Biodiversity. As part of Trinidad’s celebrations, I was invited to take part in a panel discussion on biodiversity at an event at the local Green Market. This post originally appeared on my research group's website.
On Sunday 21st September, 166 countries around the world held ‘People’s Climate’ Marches to coincide with the international climate summit in New York City. I am based in Trinidad and Tobago, where I study patterns of biodiversity – including the effect that humans can have on this biodiversity. As one of the greatest threats facing biodiversity is climate change, it is an issue I feel passionately about. So, I was delighted to hear that T&T would also be hosting their very own People’s Climate March on the same day as the events in NYC, London and all over the world. Researchers at the University of St Andrews have made a shock discovery; that restricting a normally multiply mating fish to monogamous mating does not impair their colonisation ability. Their findings show that releasing just one or two fish into the wild may be enough to trigger an aquatic invasion. In a paper published this month in the journal BMC Ecology, researchers from the University of St Andrews tested whether forcing female guppies to be monogamous would impede their ability to establish viable populations. The guppy (Poecilia reticulata) is a successful invasive species throughout the tropics. In the wild it employs a 'multiple mating' strategy, and resulting broods commonly contain offspring sired by up to five different fathers. Previous studies have shown that mating with multiple partners carries a range of benefits, including increased genetic and phenotypic diversity of offspring, and inbreeding avoidance -which are potentially advantageous for a species attempting to colonise a new environment. However, as part of this latest study, female guppies were either allowed to mate with four males, or were restricted to one partner. Pregnant females were then left to establish populations in large tanks in the laboratory. After one year, the two treatments were compared. Dr Amy Deacon explains: "One of our key findings was that mating history did not predict establishment success, which was 88% in both treatments". What's more the researchers had expected that inbreeding depression might be evident in the behaviour of fish in the monogamous treatment, which would suggest that their ability to persist once established could be limited. However, this was not the case; newborn and adult male offspring of both treatments were equally good at avoiding predators and at courting females. These results suggest that even when denied the option of multiple mating, singly-mated female guppies can produce viable populations, at least at the founder stage. The ability to colonise even when multiple mating is restricted may prove to be critical during introductions, where a few individuals are released into enclosed water bodies before finding their way into natural ecosystems. For example, guppies are commonly introduced into rivers or ponds as unwanted pets, or into troughs or wells for mosquito control, but later tend to spread to new habitats during floods or monsoons. Once established in rivers and streams, aquatic invaders are notoriously difficult to eradicate. The findings of this study reinforce the message that although seemingly harmless, releasing just one or two individuals can lead to a potentially invasive population. The full text (open access) article can be viewed at: http://www.biomedcentral.com/1472-6785/14/18 Authored by me, this press released was edited and issued by the University of St Andrews Press Office. Coverage in the media includes: http://www.heraldscotland.com/news/home-news/scientists-discover-that-monogamy-does-not-curb-colonisation-by-guppies.24607524 http://phys.org/news/2014-06-invasion-monogamous-fish.html http://cryptozoologynews.blogspot.com/2014/06/invasion-of-monogamous-fish.html This week Professor Anne Magurran attended the Euroscience Open Forum (ESOF) in Copenhagen, accompanied by a film that was produced by Steve Smart of the School of Biology to explain what the BioTIME project is all about. The video features some great presenting skills from Dr Iain Matthews, and some rather shaky amateur camera work from me! I think it gives a nice impression of what my fieldwork in Trinidad's Northern Range is really like, and what the project is all about... Below is a press release I have written to promote a paper that was recently published in the journal 'Ostrich': The lakes of Kenya’s Rift Valley boast spectacular pink aggregations of lesser and greater flamingos. Over the last 20 years these populations have suffered a series of unexplained mass mortality events, during which hundreds of thousands of birds die over a period of just a few months. Not only is this a distressing sight to witness, it is also a serious concern for conservationists. The Rift Valley lakes represent the largest of four populations of this species worldwide – consisting of around 1.5-2.5 million birds. Because only a handful of salt lakes support this huge population, these mysterious die-offs have the potential to threaten the global health of the species. Suggested causes for the die-offs range from infectious diseases such as avian tuberculosis and avian cholera, to poisoning by cyanobacterial toxins, insecticides or heavy metals. This variety of potential causes means that over the years studies have been undertaken by researchers from many different disciplines, each using different approaches. The result has been samples that cannot easily be compared with each other, and no consensus on the underlying cause. There is a real need for the standardisation of sample-taking and examination if we are to understand the causes of mortality in these birds. In a paper published this month in the journal ‘Ostrich’, Professor John Cooper, Dr Amy Deacon and Dr Thomas Nyariki present tried and tested protocols for the post-mortem examination of flamingos, so that we will be better prepared in the event of future die-offs. The strength of these easy-to-follow protocols lies in their flexibility, which allows them to be adjusted according to the available labour and number of dead birds. When there are many birds and/or few staff, the ‘super-fast track’ form ensures that the most essential data and vital samples will be prioritised; when there are fewer birds and/or more people, instructions for a comprehensive examination can be followed. Professor Cooper has confidence that the new protocols will prove vital to conservation efforts: “We believe that collecting standardised samples and measurements will be the key to finally finding the cause of these highly concerning events, and ultimately being able to prevent future die-offs and protect this globally important population.” As well as being important primary consumers in the soda lake ecosystem, the promise of the once-in-a-lifetime experience of seeing these stunning pink birds in their millions draws large numbers of international tourists to the Rift Valley. With 15,000 visitors each year to Lake Bogoria alone, the long-term protection of this species is of great economic, as well as ecological, importance to the region. Cooper, J. E., Deacon, A. E., & Nyariki, T. (2014). Post-mortem examination and sampling of African flamingos (Phoenicopteridae) under field conditions. Ostrich, 85(1), 75-83. The BioTIME fieldwork team were asked to feature in promotional film for The University of the West Indies, Faculty of Science and Technology. We were happy to oblige and spent an hour or so in the rain re-enacting collecting a data logger several times over. The results can be seen below (we feature in the first minute of the video). More than just guppies: Arima Valley’s freshwater fauna A report originally published in the TTFNC Quarterly Bulletin, by Amy Deacon and Ryan Mohammed. The picturesque freshwater streams of the Arima valley are internationally famous as the subject of hundreds of scientific papers about guppy behaviour and evolution. However, the Freshwater Group for the 2013 BioBlitz was more interested in the huge variety of species which share the habitat – from larger guppy-eating fish like the sardines (Characins), to the microscopic rock-bound diatoms on which guppies graze. Led by Amy Deacon, Ryan Mohammed and Erin Mangal, a full and enthusiastic team sampled seven sites all the way from Verdant Vale, including Simla, Temple Village and sites within the grounds of the AWNC itself. These sites included some deep pools as well as shallow riffles. Using two-person hand seine nets we recorded a total of six species of fish, including the spectacular zangee (Synbranchus marmoratus) and an unusually large sardine (Astyanax bimaculatus). Fish pots were also used overnight with limited success due to the shallow depth of the river, but nonetheless yielded Trinidad’s two species of teta – ‘normal’, and ‘jumbie’ or ‘doctor’ teta (Hypostomus robini and Ancistrus maracasae). Despite doubling the total of last year’s Tucker valley snapshot, six species is certainly an underestimate of what are actually there. Notable absences included the cichlids, Crenicichla sp. and Andinoacara pulcher. Thanks to help from afar from Odonata expert John Michalski in the form of an illustrated list, we were able to identify several species of dragonflies and damselflies relatively easily – some of the prettiest were spotted at the Simla cement ponds, including the beautiful turquoise Micrathyria atra. Our efforts to sample Odonata extended to capturing some of the aquatic larvae as well, using a surber sampler. This piece of equipment also allowed us to catch and identify the larval stages of mayflies, caddisflies, stoneflies and various other bottom-dwelling macroinvertebrates. One crustacean species was confirmed - the manicou crab (Eudaniela garmani) and several aquatic gastropods including Pomacea glauca and Marisa cornuarietis. Back at base camp on Sunday morning, children enjoyed taking part in our ‘colour in the guppy’ competition, and visitors could view fish in the display tanks. There were also some wriggling aquatic invertebrates to look at under the microscope and posters all about some of the streams’ smallest inhabitants - the diatoms. These are tiny photosynthetic creatures encased in intricate glass shells and are normally invisible to the naked eye. However, under the microscope it is possible to admire their beauty and diversity at close range. We identified at least six different species of diatoms in the Arima Valley waterways. Once again, the Freshwater Group have revealed hidden secrets of Trinidad’s streams, opening peoples’ eyes to the weird and wonderful creatures that grow, swim and crawl alongside the fish… |
NewsA place to post relevant stories and updates Archives
December 2022
Categories
All
|