5/21/2015  |   13:30 - 13:45   |  101B

EFFECTS OF DISTURBANCES ON UPSTREAM AND DOWNSTREAM MOVEMENTS: WHEN AND WHERE ARE DROUGHTS LIKELY TO HAVE THE MOST IMPACT ON NEOTROPICAL HEADWATER STREAMS? Most Caribbean headwater streams are non-seasonal and base flows persist throughout the year. However, regional climate models predict prolonged droughts are likely to be more common in the future. Our long-term data since 1990 demonstrate that dry periods affect the abundance and spatial distributions of freshwater shrimps. In general, these migratory species are positively rheotactic and move into the direction of flow. However, distributions of large river shrimp (Macrobrachium spp.) are typically limited to deeper, downstream pools. In contrast to expectations, high concentrations of Macrobrachium in the lower pools apparently caused behavioral shifts resulting in upstream movement to the highest headwater pools for two years following 1994, the driest year of record. Determining changes in the directions and distances of movement could serve as an indicator of drought intensity and duration for regional comparisons among tropical rainforest streams. With projected increases in droughts it is important to understand which physical and biotic variables trigger shifts in the patterns of movement that might alter sustainability of these ecologically and economically significant populations.

Alan Covich (Primary Presenter/Author), Odum School of Ecology, University of Georgia, a.covich@gmail.com;


Todd Crowl (Co-Presenter/Co-Author), Florida International University, facrowl@gmail.com;


Omar Perez-Reyes (Co-Presenter/Co-Author), University of Puerto Rico- Rio Piedras, macrobrachium@gmail.com;

5/21/2015  |   13:45 - 14:00   |  101B

LONG-TERM EFFECTS OF DISEASE-DRIVEN AMPHIBIAN DECLINES ON MACROINVERTEBRATE COMMUNITIES IN TROPICAL STREAMS Disease-driven amphibian declines in neotropical headwater streams have affected ecosystem functioning and macroinvertebrate community structure. We examined changes in macroinvertebrate communities associated with amphibian declines in 10 Panamanian headwater streams that provided a chronosequence of pre- and post-decline conditions. Total macroinvertebrate taxa richness declined with time since amphibian declines across all streams (P<0.05, r2=0.31), and declines appeared mostly related to non-consumptive effects of tadpoles. Macroinvertebrate community analyses from two sites indicate that communities are becoming more similar 5 years after declines compared to pre-decline conditions (ANOSIM, P<0.05).Consistent post-decline changes in macroinvertebrate communities included decreases in the biomass of shredders, filter-feeders, and the total community but increased biomass of collector-gatherers. Taxonomic changes included Farrodes replacing Thraulodes as the abundant scraping mayfly, and shifts in predator taxonomic composition. Though the mechanisms underlying these responses are not clear, we hypothesize that dietary plasticity as related to shifts in basal resources associated with tadpole grazing and bioturbation had a crucial role in structuring the post-decline invertebrate community.

Heidi Rantala (Primary Presenter/Author), Southern Illinois University, hrantala74@gmail.com;


Amanda Rugenski (Co-Presenter/Co-Author), University of Georgia, atrugenski@gmail.com;


Thomas Barnum (Co-Presenter/Co-Author), USEPA-ORD, tbarnum32@gmail.com;


Checo Colon-Gaud (Co-Presenter/Co-Author), Georgia Southern University, jccolongaud@georgiasouthern.edu;


Cesc Múrria (Co-Presenter/Co-Author), University of Barcelona, cmurria@gmail.com;


Matt Whiles (Co-Presenter/Co-Author), University of Florida, mwhiles@ufl.edu;

5/21/2015  |   14:00 - 14:15   |  101B

LOW RESILIENCE OF TROPICAL RIVER BIOTA TO EXPERIMENTAL DECREASE IN GLACIER RUNOFF Worldwide climate-driven changes in glacier runoff regimes have important consequences on the hydrological cycle and on the remarkable aquatic biodiversity of alpine valleys. Yet we still lack an in-depth mechanistic understanding of glacier retreat impacts on aquatic biota and evaluation of biological resilience. We addressed this issue through a 4 year-experimental glacier runoff manipulation in a tropical aquatic food web. Flow reduction altered benthic algae and fauna community composition in less than a couple of weeks but it took the system c.a. 14-16 months to return to its initial ecological state after perturbation ceased. Lower water flow abruptly modified food web organization by enhancing both algal and herbivore biomass, pushing the system to alternate trophic states, in line with predictions of ecological state theory. This research provides the first experimental evidence of the profound effects increased glacier runoff variability can have on alpine rivers structure and functioning: alterations in species composition will lead to alternate ecosystem states with limited capacities to rebound. It highlights that predictions of aquatic diversity with respect to climate change must emphasize indirect trophic interaction effects.

Sophie Cauvy-Fraunié (Primary Presenter/Author), IRSTEA Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture, sophie.cauvy@gmail.com;

5/21/2015  |   14:15 - 14:30   |  101B

ECOLOGY AND MANAGEMENT OF NEOTROPICAL RIVERS: LESSONS FROM THE CLOUD FOREST IN ECUADOR We explored functional feeding group associations in five cloud forest streams located in the Reserva las Gralarias at mid-elevation on the Western front of the Andes Mountains, Mindo, Ecuador. Aquatic insect guilds were consistent with patterns reported elsewhere (high predator/prey ratio, heterotrophic, and dependence on upstream processing and supply of FPOM). We also found that there was a predictable shift in FFG ratios from 1st through 4th order. Specifically, an increasing dependence on autotrophic production, decrease in predator representation, and increase in benthic POM. No significant impact of upstream grazing was detected, and ongoing research seeks to understand reciprocal subsidies and food web dynamics between streams and endemic glass frogs (F. Centrolenidae) using stable isotope analyses. This project is part of an ongoing biennial study-abroad class and is a useful tool for evaluating potential grazing impacts by establishing and tracking baseline conditions.

Eric Snyder (Primary Presenter/Author), Grand Valley State University, snydeeri@gvsu.edu;


Tim Kynak (Co-Presenter/Co-Author), Cleveland Metroparks, tkrynak85@gmail.com;


Katherine Krynak (Co-Presenter/Co-Author), Ohio Northern University, k-krynak@onu.edu;


Jane Lyons (Co-Presenter/Co-Author), Reserva las Gralarias, jalyons593@gmail.com;

5/21/2015  |   14:30 - 14:45   |  101B

THE USE OF MACROINVERTEBRATES IN BIOMONITORING OF FRESHWATER HABITATS IN MESOAMERICA AND THE CARIBBEAN Biomonitoring for water quality and environmental studies began only recently in the majority of Latin American countries, and efforts have been undertaken in order to establish the use of freshwater macroinvertebrates as biological indicators. In the Mesoamerican region, from Mexico to Panama, and in the Caribbean, several countries have developed their own indices (e.g. Cuba, Costa Rica, El Salvador), or are in the process of adopting one (e.g. Panama, Puerto Rico). These are mainly biotic indices at the family level, such as the Hilsenhoff Family Biotic Index, adapted for El Salvador, and the BMWP-index (Biological Monitoring Working Party index, first established for England), which was adapted for Costa Rica and Cuba, in 2007 and 2005, respectively. In Costa Rica, the awareness about the usefulness of macroinvertebrate assemblages as indicators of water quality, along with concern about the high degree of contamination in many rivers in the country, has led to their being included in an executive decree. This unique regulation governs the evaluation and classification of the quality of surface water bodies and establishes the BMWP-CR index for biological monitoring.

Monika Springer (Primary Presenter/Author), University of Costa Rica, School of Biology and CIMAR, biomonitoreo@gmail.com;

5/21/2015  |   14:45 - 15:00   |  101B

MONITORING STREAM BIO-INTEGRITY USING MACROINVERTEBRATES IN A HIGH INTENSITY COFFEE-GROWING REGION: CONTRASTING AN INDEX BASED APPROACH WITH REFERENCE SITE COMPARISONS IN THE PIRRIS WATERSHED, COSTA RICA Coffee farming is an important land use type in tropical highlands, yet there are few studies addressing its impact on aquatic communities. The goal of this study was to provide descriptive baseline data to fill this information gap. We monitored benthic macroinvertebrate families for one year on 17 sub-watersheds dominated by intense coffee farming within Costa Rica’s Pirris watershed. We followed 1) an index based approach, using biotic integrity indices, and 2) a reference site approach by comparing a sub-set of our sites (N=5) with a forested sub-watershed. The index-based approach classified most of our sites as “good” suggesting that coffee farming has moderate impact on bio-integrity. On the other hand, the reference site comparison showed a different assemblage of macroinvertebrate families in coffee streams relative to the forested site, with a steep decline in the proportion of shredders in the coffee streams. Our results suggest that intense coffee farming may lead to changes in the functional structure of local streams, and that that this change is not detected by following an index-based approach to assess biotic integrity.

Rebeca de Jesus Crespo (Primary Presenter/Author), Odum School of Ecology, The University of Georgia, rdejesus@uga.edu;


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