SFS Annual Meeting

Suman Jumani (Primary Presenter/Author)
University of Florida, sumanjumani@ufl.edu;

Matthew Deitch (Co-Presenter/Co-Author)
University of Florida, West Florida Research and Education Center, mdeitch@ufl.edu;

Abstract: Developing countries, like India, are witnessing a proliferation of dams to meet their demands. Thousands of dams are planned for future development in India’s Western Ghats, a biodiversity hotspot and freshwater ecoregion, with little consideration to impacts on biodiversity and local communities. Recognizing the need for a spatially explicit and empirically validated measure of river connectivity that can be applied in data-deficit regions, we propose the Area- and Rainfall-based Fragmentation Index (ARFI). Based on the Dendritic Connectivity Index (DCI) by Cote et al. (2009), the ARFI provides users with an easy-to-compute index while addressing the drawbacks of the DCI (which treats stream reaches across a longitudinal profile as equivalent). Since structural connectivity metrics do not necessarily predict functional connectivity, we test the ecological validity of the DCI and ARFI based on freshwater fish communities across dammed and undammed streams. We then apply these metrics to assess various scenarios of past, present, and future dam development in the west-flowing rivers of the Western Ghats. Finally, we assess the trade-offs between hydropower generation/irrigation and river fragmentation to identify ‘good’ and ‘bad’ dams, no-go river stretches, and priority mitigation zones.

Alonso Ramírez (Co-Presenter/Co-Author)
North Carolina State University, alonso.ramirez@ncsu.edu;

Ana Meza-Salazar (Primary Presenter/Author)
North Carolina State University, ammezasa@ncsu.edu;

Abstract: Freshwater ecosystems are expected to face major impacts from our changing climate. Understanding how streams might respond is critical, in particular in the tropics where we have limited information. Here, we (1) summarize current information of climate change projections in the Caribbean region, and (2) discuss potential stream ecosystem responses in coastal and mountain areas. We conducted a literature review of climate projections for the Caribbean and used our studies in Costa Rica (coastal streams with different groundwater inputs) and Puerto Rico (mountain ecosystems) to assess potential responses to those projections. Projected changes include increases in air temperature and drought events, and mean precipitation is expected to decrease. Among these changes, droughts could have a more significant effect as they are unusual in rainy regions. Responses in coastal ecosystems are potentially related to the change of the stream chemical composition related to groundwater inputs. In mountain streams, drought reduces connectivity along the channel creating isolated pools more similar to lentic ecosystems. In conclusion, we expect reduced precipitation to be the major impact associated with climate change in the Caribbean, with contrasting responses between coastal and mountain streams.

Claire Beveridge (Co-Presenter/Co-Author)
Florida International University, cbeverid@fiu.edu;

Guido A Herrera-R (Co-Presenter/Co-Author)
University of Tennessee, guidohero@hotmail.com;

Sebastian Heilpern (Co-Presenter/Co-Author)
Cornell University, s.heilpern@cornell.edu;

Elizabeth P Anderson (Co-Presenter/Co-Author)
Florida International University, epanders@fiu.edu;

Thiago Couto (Primary Presenter/Author)
Florida International University, tbelisar@fiu.edu;

Abstract: The Western portion of the Amazon Basin amidst the Andes Mountains is where the journey begins for most Amazonian streamflow and for the fishes that perform the longest freshwater migrations — both water and fishes move thousands of kilometers downstream to the estuary. However, the critical connections between the Western, Andean drainages and the Amazonian lowlands are under growing threat due to increasing infrastructure development. Here, we use geospatial analysis to assess the current and projected-future state of longitudinal river connectedness across Western Amazon riverscapes. Our analysis considered road crossings over first to fourth order streams and existing and planned hydropower dams, which together summed thousands of potential barriers spread throughout the different basins. The Caquetá, Putumayo, Javari, Juruá and Purus are the only basins that currently remain free of existing hydropower dams. The Madeira River is heavily fragmented by infrastructure development, which includes two major dams in the lower mainstem that isolate critical spawning habitats for the goliath catfish Brachyplatystoma rousseauxii. Our results highlight the threat of river fragmentation in the Western Amazon and identify conservation priorities for maintaining the connectivity between the Andes to the Amazon lowlands.

Sebastian Heilpern (Primary Presenter/Author)
Cornell University, s.heilpern@cornell.edu;

Ruth DeFries (Co-Presenter/Co-Author)
Columbia University, rd2402@columbia.edu;

Kathryn Fiorella (Co-Presenter/Co-Author)
Cornell University, kfiorella@cornell.edu;

Alexander Flecker (Co-Presenter/Co-Author)
Cornell University, Ithaca, NY, USA, asf3@cornell.edu;

Suresh Sethi (Co-Presenter/Co-Author)
Cornell University, suresh.sethi@cornell.edu;

María Uriarte (Co-Presenter/Co-Author)
Columbia University, mu2126@columbia.edu;

Shahid Naeem (Co-Presenter/Co-Author)
Columbia University, sn2121@columbia.edu;

Abstract: Although biodiversity loss adversely influences a wide array of ecosystem functions, how declines in wild-caught species diversity influences nutrients supplied to people who depend on wild foods is poorly understood. Freshwater fisheries provide over 150 million people across the world with their primary sources of essential nutrients but are increasingly threatened by hydropower development and overharvesting. Here we analyze the impact of declining harvest biodiversity on nutrient supplies from fish, using detailed information from the Peruvian Amazon, where inland fisheries provide a critical source of dietary nutrients. Realistic extinction scenarios revealed that the impacts of biodiversity loss on nutrient supplies depended on compensatory growth, trophic dynamics and functional diversity. When small sedentary species compensated for declines in large migratory species, fatty acid supplies increased, while zinc and iron supplies decreased. In contrast, the probability of failing to maintain supplies, or nutrient supply risk, increased when species were nutritionally unique, or when communities exhibited low response diversity. Our results show that trait-based regulations and public health policies need to consider the vital role of biodiversity in sustaining the nutritional benefits people regularly derive from wild foods such as inland fisheries.

Beatriz Moreira Ferreira (Primary Presenter/Author)
Universidade do Estado do Rio de Janeiro, biaferreira.biologia@gmail.com;

Flavia Tromboni (Co-Presenter/Co-Author)
University of Nevada, Reno, ftromboni@unr.edu;

Vinicius Neres-Lima (Co-Presenter/Co-Author)
Universidade do Estado do Rio de Janeiro, vinicius.lima.eco@gmail.com;

Priscila Cunha (Co-Presenter/Co-Author)
Universidade do Estado do Rio de Janeiro, priscilacunhaoli@gmail.com;

Eugenia Zandona (Co-Presenter/Co-Author)
Universidade do Estado do Rio de Janeiro, eugenia.zandona@gmail.com;

Abstract: Increasing nutrient concentrations, altering ecosystem characteristics and fish communities are some of the impacts caused by deforestation that affect ecosystem functioning. Fish contribution in nutrient dynamics, by recycling nutrients through excretion, can be altered by human impact. In this study we investigated how land-use affected the role of a fish species (Characidium vidali) as a nutrient provider in six streams along a deforestation gradient in the Atlantic rainforest in Brazil. We measured fish density, SRP and NH4+-N excretion and uptake rates to estimate the contribution of fish excretion relative to the ecosystem nutrient demand. Deforestation was not associated with increases in background nutrient concentrations, reductions in uptake rates, or in fish density. Deforestation also did not affect the role of fish as nutrient recyclers. Fish density was the only factor that affected the importance of excretion for the ecosystem demand. This is the first study in the Neotropics that investigates the potential effects of changing land-use on consumer-driven nutrient recycling. More studies on stream degradation are needed to comprehend human impact on fish as regulators of ecosystem processes in order to design conservation strategies.

Stephen K. Hamilton (Primary Presenter/Author)
Michigan State University & Cary Institute of Ecosystem Studies, hamilton@kbs.msu.edu;

Ibraim Fantin-Cruz (Co-Presenter/Co-Author)
Federal University of Mato Grosso, ibraimfantin@gmail.com;

Marcia Divina de Oliveira (Co-Presenter/Co-Author)
Empresa Brasileira de Pesquisa Agropecuaria, marcia.divina@embrapa.br;

Juliana Andrade Campos (Co-Presenter/Co-Author)
Federal University of Rio Grande do Sul, juliana_esa@outlook.com;

Olavo Pedrollo (Co-Presenter/Co-Author)
Federal University of Rio Grande do Sul, olavopedrollo@gmail.com;

Abstract: Small hydropower (SHP) facilities are increasingly built around the world and are viewed as less environmentally harmful than larger dams. Numerous SHPs have been built, and many more are proposed, in rivers draining into the Pantanal, a world-renowned floodplain wetland. Upland tributaries transport nutrients and sediments into the Pantanal, thereby affecting geomorphological dynamics and biological productivity of downstream floodplains. This study presents measurements from upstream and downstream of 25–29 current facilities. In addition, a predictive model using artificial neural networks estimated the impact of building 80 future SHPs. Changes in nitrogen and phosphorus transport were usually undetectable, whereas more than half of current facilities retained suspended sediments. However, model predictions for proposed hydropower facilities, many on rivers with higher discharge and sediment loads, suggest significant reductions in overall nitrogen (8%), phosphorus (29%), and sediment (62%) transport. This study shows that building SHPs on sediment-rich rivers may prove problematic for the facilities as well as for downstream ecosystems, mainly because of sediment trapping. Several river systems should be excluded from hydropower development to maintain the nutrient and sediment supply to the Pantanal as well as to preserve migratory fish routes.

Alonso Ramírez (Primary Presenter/Author)
North Carolina State University, alonso.ramirez@ncsu.edu;

Pavel Garcia (Co-Presenter/Co-Author)
Organismal Biology, Ecology and Evolution Program, University of Montana, pavel.garciasoto@umontana.edu;

Pablo Gutiérrez-Fonseca (Co-Presenter/Co-Author)
University of Costa Rica, pabloe.gutierrezfonseca@gmail.com;

Gabriela Vazquez (Co-Presenter/Co-Author)
INECOL, Mexico, gabriela.vazquez@inecol.mx;

Abstract: Disturbances to riparian zones that alter vegetation cover can change the trophic basis of stream food webs. Reductions in tree cover decrease inputs of allochthonous carbon and increase solar radiation to the channel. The predicted result is an increase in primary production and a switch in the carbon basis of foodwebs from allochthonous to autochthonous. Here, we assessed this prediction by studying the response of tropical streams to two major disturbances: land use conversion from forest to pasture in Mexico and hurricane impacts in Puerto Rico. Both disturbances reduced riparian vegetation, decreased leaf litter inputs, and increased solar radiation. We expected food webs to switch to autochthonous carbon. We sampled biofilms from rocks, collected leaf litter, and obtained carbon isotopic signals. We used Bayesian models to determine the proportion of autochthonous and allochthonous carbon. Both disturbances resulted in highly allochthonous biofilms. The dominance of allochthonous carbon indicates that vertical inputs of leaf litter are not the only source of riparian carbon for tropical streams. The prevalence of heavy rains suggests a role for runoff in moving carbon and scouring algal biomass in the channel.

Catherine Pringle (Co-Presenter/Co-Author)
Odum School of Ecology, University of Georgia, cpringle@uga.edu;

Alonso Ramírez (Co-Presenter/Co-Author)
North Carolina State University, alonso.ramirez@ncsu.edu;

Pablo E. Gutiérrez-Fonseca (Primary Presenter/Author)
University of Costa Rica, pabloe.gutierrezfonseca@gmail.com;

Abstract: Understanding how communities change over time is a key goal in Ecology, as it allows us to elucidate the functioning of ecosystems. Long-term data is essential to accurately evaluate natural variability, yet multi-year data is not easily available for tropical streams. Here, we evaluated assemblage dynamics in two Neotropical lowland streams using a unique long-term (20y) dataset. We considered the following questions: 1) what is the turnover of macroinvertebrates?, 2) are variations in macroinvertebrate composition synchronous or asynchronous?, and 3) what is the trajectory of the assemblages throughout time? We used analyses of community stability and temporal dynamics to evaluate our long-term data. Our results demonstrate a high turnover rate in both streams (mean: 57%, range from 14.4% to 90.0%). Synchrony measurements revealed that assemblages were asynchronous, suggesting that the organisms vary independently of one another. The rate of community change in our streams indicates that the assemblage has a directional change, increasing dissimilarity over time (slope > 0). Our findings suggest that macroinvertebrate assemblages in tropical streams are highly variable and that temporal patterns are nearly stochastic. Therefore, these tropical macroinvertebrate assemblages are in a loosely stable equilibrium.

Luisa Manna (Primary Presenter/Author)
Universidade do Estado do Rio de Janeiro , luisamanna@gmail.com;

Jeferson Ribeiro Amaral (Co-Presenter/Co-Author)
Cornell University, jefersonr.amaral@gmail.com;

Piata Marques (Co-Presenter/Co-Author)
Universidade do Estado do Rio de Janeiro, piata_bio@yahoo.com.br;

Eugenia Zandona (Co-Presenter/Co-Author)
Universidade do Estado do Rio de Janeiro, eugenia.zandona@gmail.com;

Rana El-Sabaawi (Co-Presenter/Co-Author)
University of Victoria, rana@uvic.ca;

Rosana Mazzoni (Co-Presenter/Co-Author)
Universidade do Estado do Rio de Janeiro, romazzoni.uerj@gmail.com;

Abstract: Guppies (Poecilia reticulata) have been introduced worldwide mainly for biological control of mosquito-borne diseases but there is no consensus about their efficiency for this purpose. Here, we tested the efficiency of guppies and two native Brazilian poeciliids (Poecilia vivipara and Phalloceros harpagos) to feed on mosquito larvae. We introduced fish from wild populations into 20 flowerpots (12L each) in four experimental treatment blocks. Each flowerpot was randomly assigned no-fish (control), four individuals of P. reticulata, four individuals of P. vivipara, or four individuals of P. harpagos. Three hours after introduction, we retrieved the fish for gut content analysis and estimated the insect larvae remaining in each flowerpot. All three species consumed similar (F=2.316; p=0.149) low proportions of mosquito larvae (P. reticulata=12.5%; P. harpagos=8.33% and P. vivipara=34.37%). Although there were few mosquitos in their guts, we observed a reduction in the mosquito larvae remaining in the flowerpots with fish when compared to no-fish treatments (F=14.59, p<0.001). Our data suggest that presence of fish can reduce the abundance of mosquito larvae, regardless of fish species. As such, there is no a priori reason for using invasive, such as guppies for mosquito control.

Paulo Olivas (Primary Presenter/Author)
Florida International University, Paolivas@fiu.edu;

Maria Pulido (Co-Presenter/Co-Author)
Florida International University, mpuli012@fiu.edu;

Thiago Couto (Co-Presenter/Co-Author)
Florida International University, tbelisar@fiu.edu;

Gina Leite (Co-Presenter/Co-Author)
Wildlife Conservation Society, gleite@wcs.org;

Mariana Varese (Co-Presenter/Co-Author)
Wildlife Conservation Society, mvarese@wcs.org;

Shah Selbe (Co-Presenter/Co-Author)
Conservify, shah@conservify.org;

Elizabeth P Anderson (Co-Presenter/Co-Author)
Florida International University, epanders@fiu.edu;

Abstract: As diverse and complex systems, tropical rivers play a key role in local and regional biogeochemical and hydrological cycles. However, the spatial and temporal variability in environmental conditions many tropical rivers is poorly understood, often as a result of the high cost associated with monitoring. Several Amazonian countries, like Brazil, have established sophisticated networks for environmental monitoring of the lower part of the basin. However, areas in the Andean headwaters and central Amazon still lack monitoring networks and therefore understanding of the temporal and spatial variability of basic environmental parameters remains limited. Given the size and complexity of the Amazon basin, it would be cost prohibitive for a single organization to be able to implement and maintain a monitoring network. Partnership with local institutions in Amazonian countries can help provide necessary resources to increase the spatial information on water resources. Here, we describe our experiences with use of low cost, modular monitoring systems, such as water quality sensors, as well as mobile and web applications for data collection, management, and dissemination. The environmental monitoring network is based on a community science framework in five Amazonian countries.

Cecilia Leal (Co-Presenter/Co-Author)
University of São Paulo “Luiz de Queiroz” College of Agriculture (ESALQ/USP), c.gontijoleal@gmail.com;

Felipe Rossetti de Paula (Co-Presenter/Co-Author)
University of São Paulo “Luiz de Queiroz” College of Agriculture (ESALQ/USP), ferossetti@gmail.com ;

Silvio Frosini de Barros Ferraz (Co-Presenter/Co-Author)
University of São Paulo, USP/ESALQ, Dept of Forest Sciences, Brazil, silvio.ferraz@usp.br;

Gláucia Regina Santos (Primary Presenter/Author)
University of São Paulo “Luiz de Queiroz” College of Agriculture (ESALQ/USP), glauciaflorestal@usp.br;

Abstract: Land use change and intensification are among the main threats to tropical headwater streams. However, information about the impacts on the stream physical habitat is still poorly documented in the tropics. To address this knowledge gap, we investigated how substrate and wood responded to a gradient of land use intensity (agriculture with low and high percentage of riparian forest, young and old Eucalyptus plantations and native forests (reference)) in 18 streams in the Atlantic Rainforest, Brazil. Small sized substrate (fine gravel, sand and silt) predominated in streams with high land use intensity, whereas streams in native forests had larger substrate size (cobbles and boulders). Streams in young Eucalyptus plantation presented the largest amount of leaves. Large wood responded negatively to the increase in land use intensity. Although Eucalyptus leaves have a low decomposition rate, they can be used as refuge for fauna, as well as woods, cobbles and boulders, having positive effects instreams. The gradual reduction of forest fragmentation and increase in the extent of native forests (not just riparian forests), improved the physical habitat of streams and can have positive effects on the restoration of aquatic ecosystems.

Jeferson Ribeiro Amaral (Primary Presenter/Author)
Cornell University, jefersonr.amaral@gmail.com;

Abstract: Intraspecific variability in diet can be used as a tool for understanding the trophic interactions between invasive and native fish species. Individuals can change their trophic niche width in the presence of closely-related species but the effects of invaders on intraspecific diet variability (IDV) of native species is still understudied. Our objective was to analyze how the IDV in one native species (Phalloceros harpagos) changed according to the presence of a common invasive species (guppy - Poecilia reticulata). We hypothesized that guppies' presence will reduce the natives' trophic niche width by reducing IDV, as an effect of interspecific competition. We collected fish from streams in Brazil where species were found in allopatry and sympatry. Our results revealed high IDV in both species when in allopatry. The native species shifted its trophic niche when occurring in sympatry with guppies by reducing their IDV as expected. These results suggest that guppy invasion impacts functionally similar native fish by affecting the individuals' trophic variability.

Siddarth Machado (Primary Presenter/Author)
University of Florida, siddarthmachado@ufl.edu;

Suman Jumani (Co-Presenter/Co-Author)
University of Florida, sumanjumani@ufl.edu;

Abstract: Small hydropower projects (SHPs) are being widely promoted as environmentally benign and socially beneficial sources of renewable energy, particularly in tropical developing countries. In the Western Ghats of Karnataka state alone ~500 SHPs have been proposed in addition to ~110 SHPs that already exist as of 2015. Our study is the first to assess the ecological and social impacts of a cluster of four SHPs in the Western Ghats biodiversity hotspot in India. Field work was conducted in 2014 to quantify ecological impacts with respect to freshwater fish assemblages and water quality parameters. Social surveys were also conducted with local communities to understand perceived impacts of SHPs on socio-economic activities, resource access and human-animal conflict. SHPs were found to adversely affect fish species richness, diversity and community dissimilarity, particularly in dewatered stream reaches. In terms of social impacts, SHP construction coincided with the sudden onset of human-elephant conflict. Further, assured project benefits were not realized while additional costs were imposed on local communities. This study compliments the growing scientific evidence that SHPs are not socio-ecologically benign. Our findings make a strong case for operational changes and policy interventions regarding SHPs.