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August 2018 reservations@asawright.org Tel: (868) 667-4655

Studying Guppies as an Invasive Species at the William Beebe Research Station

By Douglas F. Fraser

If you enjoy liming on the banks of one of Trinidad’s beautiful rivers or gazing into the clear waters of a small stream, you may have noticed lots of small, colourful guppies. Guppies are a model species for the study of rapid, contemporary evolution. They are found naturally in Trinidad’s streams, but are also used extensively outside of their native range for the control of mosquitoes, as they readily eat their larvae. My colleague, UWI lecturer, Dr. Amy Deacon, has documented their worldwide use in controlling mosquitoes. They have established populations on every continent except Antarctica, in such far-flung places as India, Siberia, and North America, wherever there is warm water such as in factory outflows and hot springs. Also, males have fascinating courtship displays and females give birth to live babies, making them popular in the aquarium trade, and sometimes unwanted pet guppies are released into local waters, adding to their worldwide occurrence. In fact, Dr. Deacon’s studies showed this little fish to be a powerful coloniser. They can even be an unwanted invader when they relinquish their mosquito control duties and escape beyond their initial confines, e.g. during floods. Moreover, Dr. Deacon found that, owing to the female’s ability to store sperm, and other life history characteristics, such as having a short generation time, a single female guppy is all it takes to establish a healthy population in short order, just

about anywhere!

We wanted to find out whether this might also be true when there is a

resident species already present,

A single female guppy (foreground) can easily establish a population when other fish species are not already resident in a habitat, but may be slowed or prevented entirely when in the presence of predators or competitors.

One of 12 experimental pools dug alongside a natural stream in the Arima Valley and lined with black plastic used to study the invasive ability of guppies in the presence of a resident killifish.

i.e. another fish that “owns” the habitat, by controlling the food resources and possibly by being a potential predator on the guppy. We set up two simple experiments to answer this question. In one, we dug shallow pits alongside a natural stream in the Arima Valley and made the common killifish, locally called jumping guabine, the resident of these dug pools. Later, we added a female guppy to each pool. Adult killifish are about the size of one’s little finger and eat baby guppies, while baby killifish, in the size range of guppies, compete with them for aquatic insects. So, potentially, “push back” might occur during any attempt by a guppy to colonise a pool with killifish present. We also duplicated this experiment at the William Beebe Research Station (Simla) by setting up horticultural bins and varying the number of guppy females (1, 8 and 16) and the number of resident killifish in a controlled setting (see accompanying photo). Of course, we also had killifish-free pools as controls.

We found that a single female guppy could not establish when there were resident killifish present. No baby guppies appeared in these containers, in either experiment. Continued on next page

Increasing the number of colonisers up to 8 or 16 females resulted in small guppy populations in some but not all containers. When, for completeness, we reversed the order of colonisation, allowing guppies to establish first and then adding killifish, guppies almost always established. However, this situation, guppies getting into local waters first, before a common

AU G U S T • PAGE 2 August 2018

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Experimental horticulture bins at William Beebe Research Station used in controlled experiments to test for the ability of guppies to invade in the presence of resident killifish. Dr. Amy Deacon, background, with assistant Fadilah Ali.

Photos courtesy Douglas F. Fraser

resident, is an unlikely scenario. These findings have a message for the field of invasion biology.

Biotic resistance, the proper name for our guppy study, is of great interest to biologists who study invasions. In the case of streams, it has generally been thought that if the physical conditions, such as water temperature and pH, are appropriate, fish invasions will inevitably succeed, regardless of who the resident might be; biotic resistance cannot stop the invasion. Our message is that this may not always be the case, especially in small waters such as the streams and flood pools, so common in Trinidad, where there often is a resident like the killifish that can compete and potentially prey upon the invader.

YOUNG ENVIRONMENTALISTOF THE MONTHIf you think your child, aged 5-16, has done something helpful to preserve the environment, please feel free to share it with us. Either write a short story or send a few pictures to asawrightconsedu@gmail.com. He/she may be selected as our Young Environmentalist of the Month. Once your child is featured in our monthly newsletter, he/she and two adults will be given a complimentary day visit to Asa Wright Nature Centre, which includes viewing birds/animals on the verandah, a nature tour and use of the clear water pool.

Douglas F. Fraser is a professor emeritus of biology at Siena College.

Continued from page 1

Rediscover Trinidad and Tobago

Naturalist Guide, Jessie Pitt, interacts with patrons.

Photo by Elizabeth Naipaul

By Johanne Ryan

Asa Wright Nature Centre had the pleasure of participating in a mini Trade Show, ‘Rediscover Trinidad and Tobago’, hosted by students of the Trinidad and Tobago Hospitality and Tourism Institute (TTHTI). As part of a project, students developed criteria and indicators by which they assessed T&T’s tourism sites. AWNC was rated as the top

attraction and joined persons from other sites at the trade show held in Trincity Mall. There, our staff had an interactive booth where persons could learn about local flora and fauna. We thank TTHTI for inviting us. And for those who haven’t been here yet – come discover Asa Wright Nature Centre!

AU G U S T • PAGE 3 August 2018

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T&T hosts the first Latin America and Caribbean Congress for Conservation Biology

By Ryan Mohammed

The Latin America and Caribbean Section (LACA) of the Society for Conservation Biology (SCB) along with The University of the West Indies (UWI) hosted the inaugural Latin America and Caribbean Congress for Conservation Biology (LACCCB 2018) in Trinidad and Tobago from the 25th to 31st July. SCB is the world’s largest community of conservation professionals dedicated to the science and practice of conserving Earth’s biological diversity. The International Fund for Animal Welfare (IFAW), International Union for Conservation and Nature (IUCN) Species Survival Commission (SSC), Conservation Leadership in the Caribbean (CLIC), Environmental Management Authority (EMA) and Springer Publishing Company, among others, sponsored the event. The local organising committee comprised mostly of staff from the Department of Life Sciences (DLS), UWI and was chaired by member of the Board of Directors of Asa Wright Nature Centre and Coordinator of the MSc in Biodiversity Conservation & Sustainable Development in the Caribbean, DLS, Dr. Luke Rostant.

The main objective addressed conservation challenges but also gave delegates an opportunity to present new findings, initiatives, methods, tools and opportunities for collaboration in conservation science and practice. The meeting brought together communities of conservation professionals from at least 10 Latin American and Caribbean countries

with participants from as far as Europe and Australia. Participants

and attendees included scientists,

students, managers, decision-makers, writers, environmental journalists and other conservation professionals as well as several non-governmental and civil society organisations.

Plenary talks were delivered by three distinguished speakers; there was a Marie Skłodowska-Curie research fellow, Dr. Diva Amon, a Trinidad-born marine biologist, Professor Gerado Ceballos, a world-renowned environmental scientist and professor at the Universidad Nacional Autonoma de Mexico as well as, Dr. Howard Nelson, the former CEO of the Asa Wright

Nature Centre in Trinidad, FAO and UNDP consultant, and current Senior Lecturer in Conservation Biology and Programme Leader for the Masters in Wildlife Conservation at the University of Chester, in the United Kingdom.

Dr. Amon’s talk was entitled ‘Under De Sea: Exploring The Hidden Depths of The Caribbean’ while Professor Ceballos’ focused on the sixth mass extinction, and the future of biodiversity in the Neotropics. Dr. Nelson took a management approach with his presentation onconserving biodiversity beyond protected areas and valuing indigenouslandscape solutions.

The conference was divided into three main sections, comprising seven symposia, seven themed sessions (26th to 27th July) and 11 workshops (25th to 31st July). Presentations were delivered concurrently, which allowed for 80 oral presentations being delivered over the two days, including 30 student oral presentations. Poster presentations were displayed during the conference with half of these 30 posters presented by student delegates.

The organising committee was extremely grateful to Asa Wright Nature Centre and Trinidad and Tobago Field Naturalists’ Club for the contribution of prizes towards the student poster and oral presentation. Prizes included the AWNC 2018 Calendar and TTFNC’s recent publication ‘A Field Guide to the Reptiles and Amphibians of Trinidad and Tobago’. The entire event was deemed a success given the tremendous effort of the organisers and sponsors. The proceedings of the LACCCB will be published by Springer Publishing Company within the coming year.

Rachel G. Kroner receives the prize for best student oral presentation from Renoir Auguste, President of Trinidad and Tobago Field Naturalists Club. Looking on are Johanne Ryan, Conservation Officer at Asa Wright Nature Centre, Dr. Diva Amon, Plenary Speaker and Ryan S. Mohammed, LACCCB Committee Member from Department of Life Sciences

Nicholas Mohammed receives his prize for placing 3rd in the best student oral presentation category.

Photos by Alexis Marianes