ATBC 2019 Best Presentation Award Winners

2019 Luis F. Bacardi Award for Advances in Tropical Conservation

University of Antananarivo, Madagascar

The effectiveness of extinct versus extant animals as seed dispersers of Malagasy baobabs. Seheno Andriantsaralaza. Malagasy baobab trees (genus Adansonia) are hypothesized to have lost their co-evolved seed dispersers, the Malagasy megafauna including giant tortoises, giant lemurs, and elephant birds. Therefore, baobab species are considered anachronistic plants. Currently, baobab fruit consumption and seed dispersal might be assured by introduced and native mammals. We tested this hypothesis by studying the effectiveness as seed dispersal agents of extinct versus extant animals. We tested in an experimental manner the effects of baobab seeds (Adansonia rubrostipa) passage through guts in three types of animals. Indeed, we used one native species, lemurs (Eulemur rufifrons), one introduced animal species, zebus (Bos taurus), and Aldabran giant tortoises (Aldabrachelys gigantea) as ecological analog species of the extinct Malagasy giant tortoises (Aldabrachelys grandidieri and A. abrupta). We determined the dispersal effectiveness of different animal species, considering the quantity and quality components of seed dispersal. Seed dispersal quantity was the proportion of intact defecated seeds by each animal species. Quality was defined as the germination rates of gut-passed seeds. Results showed that giant tortoises dispersed a higher proportion of dung with intact seeds than zebus and lemurs. The germination of baobab seeds ingested by zebus was greater than uneaten seeds. Germination rates of seeds ingested by giant tortoises and by lemurs did not differ from those of uneaten seeds. Seed dispersal effectiveness for different animals showed a notable difference and we determined that lemurs are the most effective dispersers. These results indicate that, in the absence of Malagasy megafauna, lemurs might play an important role in Malagasy baobab population recruitment.

Universidad de Los Andes, University of East Anglia

Rapid increase in deforestation after peace agreement in Colombia: A time-series analysis. Edgar Cifuentes, James Gilroy, Pablo Negret, and Carlos Peres. On November 2016, the Colombian government and strongest local armed group, the Revolutionary Forces of Colombia – People’s Army (FARC-EP), signed a peace agreement ending more than 50 years of conflict and changing the political environment in many rural and remote areas, unleashing extractive forces, land grabbing, and deforestation. To understand the effect of the peace agreement on deforestation, we analysed tree-cover loss in Colombia using fine-scale resolution maps together with environmental and socio-political data. The chosen period encompasses 18 years of the conflict since 2000. Our results from a time series analysis using autoregressive linear mixed models showed armed conflict has had an effect in preventing higher rates of deforestation at a national scale. However, demographic and topographic variables were better predictors of deforestation. Lowland municipalities, with low rural population density, are suffering major losses of tree-cover compared to the municipalities in the Andean mountain range. The deforestation frontier is mainly expanding from the Andes foothills into the heart of the Amazon and in the Magdalena plains towards the Darien Gap. Urgent efforts in territorial planning for a post-conflict era in Colombia are needed to prevent major destruction of natural landscapes. Establishment of new protected areas and expansion of the existing ones, reinforcement of environmental agencies and control in these power vacuum areas, are essential measures that need to be taken to prevent further deforestation.

Institut Pasteur de Madagascar, Madagascar

West Nile Virus seroprevalence and risk factor in wild birds in Madagascar. Miatrana Voahangielisoa Rasamoelina, Onja H Razafindratsima, Fleurette Ravaomanana, Bruno Raveloson, Catherine Cêtre-Sossah, Cécile Beck, Sylvie Lecollinet, Tantely Randriamparany, Vincent Michel Rakotoharinome, Rivo Rabarisoa, Raliniaina Modestine, Eric Cardinale, and Hélène Guis. West Nile Virus (WNV), an important emerging zoonotic virus, is a major public health concern worldwide. Wild birds serve as the natural reservoir for WNV, but not all bird species play the same role in the life cycle of the virus. This virus is prevalent in many parts of the world, including the tropical island of Madagascar. However, only two studies report the circulation of WNV in wild birds in Madagascar. In this study, we aim to evaluate seroprevalence of WNV in wild birds in Central Highlands of Madagascar and identify which factors drive WNV exposure. We addressed this by analyzing blood samples from 352 wild birds of 40 different species, using standard protocols of testing WNV seroprevalence.  We also performed logistic regression models to identify the geographical, ecological, and biological variable(s) most associated with the serologic status of birds. The results of our analyses indicate that 12.5% of the tested birds were seropositive. These individuals belong to 19 different species, seven of which inhabit forest habitats, six inhabit wetlands, and six open areas. Three of these species inhabiting wetlands are classified as threatened.  We also found that taxonomic order of birds, their distribution area, region, and proximity to the wetlands were significantly associated to WNV exposure. In addition, interaction between region and proximity to the wetlands had the same pattern. Further work is required to investigate the clinical impact of WNV infection in these bird species. Identifying which wild bird species are more susceptible to WNV infection could allow the establishment of WNV monitoring program in wild birds in Madagascar, as has been done in other countries, both to address conservation issues and to use as an early warning tool. This could also have some important implications for the management of threatened bird populations.

2019 Alwyn Gentry Award for Best Poster Presentation

University of Oxford, United Kingdom

Effects of land-use change on avian communities of a tropical montane rainforest in Rwanda. Marie Laure Rurangwa, Robert Whittaker, Jesus Aguirre-Gutiérrez, Thomas J. Matthews, and Protais Niyigaba. Among the leading causes of biodiversity loss worldwide, land-use change figures prominently. Before the designation as a National Park in 2004, Nyungwe forest, a tropical montane rain forest in Rwanda, underwent a massive degree of transformation including: human-induced forest fires; non-native forests establishments; and agricultural encroachment driven by a continually increasing human population. There is scant information on the extent to which such habitat changes have affected birds and associated ecosystem services in Rwanda, and the Afrotropical region at large. The study aimed at determining how different degrees and forms of habitat transformation have affected avian species composition, taxonomic diversity, functional trait structure and phylogenetic diversity within the Nyungwe landscape. Data on morphological traits of study birds were collected from museum specimens. Further data on occurrence, abundance, and functional traits indicative of habitat type and use were collected using point counts, and vegetation sampling conducted in major land-use types. To quantify avian diversity, Inverse Simpson index, functional dispersion (FDis) and phylogenetic diversity (ses MNTD) were used. In comparison to pristine areas, land-use change altered species composition, and reduced species diversity and phylogenetic diversity. In contrast, functional diversity remained stable across the land-use types. Major habitat parameters driving avian diversity were found to be elevation and tree-related characteristics. Land-use change exerted varying effects on the three facets of avian diversity studied. This emphasises the need to apply complementary metrics when quantifying ecological resilience to anthropogenic changes. Long-term conservation of bird communities in the Nyungwe landscape necessitates halting wide-scale destruction of trees and extending reforestation of degraded habitats.