STRUCTURE AND FUNCTION OF STREAM ECOSYSTEMS AND THEIR RESPONSES TO GLOBAL CHANGE

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1018763
• Project Start Date: Feb 5, 2019
• Project End Date: Sep 30, 2023
• Program Code: [(N/A)]- (N/A)

Recipient Organization
NORTH CAROLINA STATE UNIV
(N/A)
RALEIGH,NC 27695

Performing Department
Applied Ecology

Non Technical Summary
Non-technicalSummaryStreams are conspicuous components of the landscape that often support a large diversity of organisms (e.g., insects, fish) and provide important services to human (e.g., drinking water). Stream ecosystems are complex, relaying on energy resources from outside the channel (leaves from riparian trees) and within channel (algae growing on rocks). Understanding their function provides valuable information for management and for maintaining services. While we have information on stream structure and function for temperate regions, our understanding of tropical streams remain rather limited. The main goal of the proposed research is to advance our knowledge of streams in general, by studying different components of tropical streams.Droughts, hurricanes, and urbanization are three important disturbances affecting stream ecosystems in tropical and temperate regions. While urbanization has been increasing in recent years at a rapid pace in many tropical regions, droughts and hurricanes are expected to increase in the future as the result of climate change. The goal of the proposed research is to improve our understanding of how those disturbances impact stream functioning and their biodiversity. Findings will improve our ability to project potential impacts on streams and allow us to best manage these valuable ecosystems and the services they provide to humans.Overall, the proposed research strives toward improving our understanding of stream ecosystem function. We will accomplish this goal by focusing on streams in Puerto Rico, Costa Rica and North Carolina. In those locations, we will study the impacts of major disturbances expected to have major impacts on streams: droughts, hurricanes, and urbanization. Finding will help improve our ability to manage and conserve stream ecosystems.

Animal Health Component

50%

Research Effort Categories

Basic

50%

Applied

50%

Developmental

0%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
135	0399	1070	100%

Knowledge Area
135 - Aquatic and Terrestrial Wildlife;

Subject Of Investigation
0399 - Watersheds and river basins, general;

Field Of Science
1070 - Ecology;

Keywords

stream ecology

disturbance

hurricane impacts

drought impacts

urbanization impacts

freshwater ecosystems

tropical streams

Goals / Objectives
Goals:The main goal of the project is to improve our understanding of how stream ecosystems function in tropical and temperate environments and how they might be affected by predicted global changes. This goal will be achieve by studying streams in Puerto Rico, Costa Rica and North Carolina.Specific goals:To understand how tropical streams are affected by major natural disturbances, in particular hurricanes and droughts. Climate change models predict an increase in the frequency of droughts and an increase in the intensity of hurricanes for the Caribbean region. The goal is to understand how those disturbances affect stream ecosystem function and structure by focusing on tropical streams in Puerto Rico.To assess the consequences of climate change on lowland tropical streams in Costa Rica. Using a long-term dataset, we identified the occurrence of climate-driven acidification events in lowland streams, which we hypothesized is the result of an influx of soil-derived CO2 via subsurface flow paths that results in pH declines, signaling a tight coupling among rainfall, terrestrial, and aquatic ecosystems.To improve our understanding of how urbanization is impacting stream ecosystems in tropical and temperate regions. Urbanization is increasing at a rapid pace in many parts of the world, representing one of the major sources of impact for stream ecosystems. The goal is to understand how urban streams function and what aspects of urban development are more closely associated with stream degradation.Understand how environmental stressors, such as pollutants or temperature, affect aquatic organisms. Using insects as model organisms, I will assess how stressors affect the biology of insects, such as dragonflies.

Project Methods
MethodsProposed research will be conducted using standard methodology for studies in stream ecology. Samples will be collected and preserved in the field, then transported to the laboratory for analysis. We will measure the following ecosystem components:Benthic macroinvertebrates: invertebrates are sample using aquatic nets (e.g., Surber samplers) and sampling devices (e.g., corers) and following quantitative sampling protocols that are standard for stream ecology. Macroinvertebrates will be identified to the lowest taxonomic level possible using available literature depending of the study location.Water chemistry: Water samples are collected for determining solute concentrations in the stream. Samples will be collected following standard protocols and analyzed in our lab or by sending them to recognized laboratories.Benthic algae: Measurements of benthic algae biomass will be conducted using protocols for chlorophyll determination. Thus, we will use chlorophyll as an indicator of algal biomass.For the development of model organisms, we will establish aquarium cultures of insects and rear them under controlled conditions. Organisms will be exposed to known contaminants and their responses will be recorded in the laboratory.Research products, mostly publications, will be shared widely using social media (e.g., twitter), our laboratory web page (www.ramirezlab.net) and our contact network. The impact will be measured as article citations over time.We will also train undergraduate students, making an emphasis on training minority students, by enrolling them in our projects as assistants and as independent researchers (e.g., NSF-REU students).Findings will be documented with photos and videos to use our research as class material in ecology courses at NCSU.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:We targeted an academic audience. Our major findings were shared in peer-reviewed scientific journals that reached an international community of experts interested in stream ecosystems in tropical and temperate areas. Our lab was also successful in training minority students. We recruited two graduate students, one of them from Puerto Rico. In addition, we enroll a number of undergraduate students to participate of the research we are conducting. During 2019 - 2020, we shared a series of research notes in social media, using our Facebook, Twitter, and Instagram accounts. The stories targeted an international audience interested in freshwater ecosystems and scientific research. Changes/Problems:Due to the Covid-19 pandemic, we had to limit our laboratory work and reduce fieldwork. We managed to maintain our field sampling, in particular for long-term projects,missing sampling only during May 2020. However, most objectives were delayed as we were unable to conduct research during summer 2020. What opportunities for training and professional development has the project provided?We enrolled two graduate students in our research program. Mariely Vega, doctoral student, is working on understanding the effects of droughts and hurricanes on tropical streams in Puerto Rico. Ana Meza, doctoral student, is working on assessing the effects of acidification on tropical lowland streams in Costa Rica. We also enrolled a number of undergraduates, before Covid-19, to participate of our projects and process macroinvertebrate samples. How have the results been disseminated to communities of interest?We presented our research findings at international scientific conferences, in particular the annual meeting of the Society for Freshwater Science. The event was virtual during summer 2020. We are now working on manuscripts for peer-reviewed journals. For a broader public, we are sharing stories in social media (Facebook, Instagram, and Twitter) highlighting different aspects of our research. Some stories are focused on results, while other highlight methodologies. Our audience is composed of students and early career researchers interested in tropical streams and their conservation. What do you plan to do during the next reporting period to accomplish the goals?We will continue experiments and monitoring to accomplish our main goals. Results will be presented at scientific meetings.

Impacts
What was accomplished under these goals? Accomplishments under specific goals: Goal: To understand how tropical streams are affected by major natural disturbances. We assessed the response of tropical streams to drought in Puerto Rico. Droughts are rare in the Caribbean and we found tropical rainforest streams in Puerto to be highly vulnerable to them. Droughts affected multiple components of stream ecosystems with consequences that resulted in changes in ecosystem function. Goal: To assess the consequences of climate change on lowland tropical streams in Costa Rica. We continue monitoring lowland streams at La Selva Biological Station. Streams experience episodic acidification events related to changes in precipitation and subsequent runoff. Acidification stresses aquatic fauna and alters stream function. However, some groups appear adapted to those changes and impacts are not equal on all ecosystem components. Goal: To improve our understanding of how urbanization is impacting stream ecosystems in tropical and temperate regions. We continue monitoring the Rio Piedras watershed in Puerto Rico, our long-term urban stream site. In addition, we are starting to monitor Rocky Branch, a small restored urban stream on campus. Goal: Understand how environmental stressors, such as pollutants or temperature, affect aquatic organisms. We are developing the use of a small species of midge, Chironomidae, as a model for understanding the impacts of stressors on aquatic organisms. We developed a method to maintain insect colonies in the laboratory; the next step is to start conducting experiments.

Publications

• Type: Journal Articles Status: Published Year Published: 2021 Citation: Reyes-Maldonado, R., A. Ramirez, B. Marie. 2021. Rearing methods and life cycle characteristics of Chironomus sp. Florida (Chironomidae: Diptera): a rapid-developing species for laboratory studies. PlosOne 16:e0247382
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Zimmerman, J.K., T.E. Wood, G. Gonz�lez, A. Ramirez, W. Silver, M. Uriarte, M.R. Willig, R.B. Waide, & A.E. Lugo. 2021. Disturbance and Resilience in the Luquillo Experimental Forest. Biological Conservation 253:108891
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Ram�rez, A., M. Caballero, G. V�zquez & C. Col�n-Gaud. 2020. Preface: Recent advances in tropical lake research. Hydrobiologia 847: 41434144
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Walteros, J.M., & Ram�rez, A. 2020. Urban streams in Latin America: current conditions and research needs. Revista de Biolog�a Tropical 68 (Suppl. 2): S13-S28
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Ram�rez, A., & Guti�rrez-Fonseca, P.E. 2020. Freshwater research in Latin America: Current research topics, challenges, and opportunities. Revista de Biolog�a Tropical 68 (Suppl. 2): S1-S12
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Ram�rez A, Maldonado-Ben�tez N, Mariani-R�os A, Figueroa-Santiago J. 2020. Dragonflies and damselflies (Odonata) from Puerto Rico: a checklist with notes on distribution and habitat. PeerJ 8:e9711 http://doi.org/10.7717/peerj.9711
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Guti�rrez-Fonseca PE, & Ram�rez A. 2020. Mayfly emergence production and body length response to hydrology in a tropical lowland stream. PeerJ 8:e9883 DOI 10.7717/peerj.9883
• Type: Book Chapters Status: Published Year Published: 2020 Citation: Boyero L, Pearson RG, Albari�o RJ, Callisto M, Correa-Araneda F, Encalada AC, Masese F, Moretti MS, Ram�rez A, Sparkman AE, Swan CM. 2020. Identifying stream invertebrates as plant litter consumers. In Baerlocher, F., Gessner, M.O., Graca, M.A.S. (eds). Methods to study litter decomposition - A practical guide. Springer
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Novelo Guti�rrez R, & Ram�rez A. 2020. First record of Perithemis thais Kirby, 1889 for Central America (Odonata: Anisoptera: Libellulidae). Argia 32: 29
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Van Beusekom, A.E., G. Gonz�lez, S. Stankavich, J.K. Zimmerman, & A. Ram�rez. 2020. Understanding Tropical Forest Abiotic Response to Hurricanes using Experimental Manipulations, Field Observations, and Satellite Data. Biogeosciences 17: 31493163
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Guti�rrez-Fonseca, P. E., Ram�rez, A., Pringle, C. M., Torres, P. J., McDowell, W. H., Covich, A., Todd Crowl, & P�rez-Reyes, O. (2020). When the rainforest dries: Drought effects on a montane tropical stream ecosystem in Puerto Rico. Freshwater Science 39(2): 197-212
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Rosas, K.G., Col�n-Gaud, C. & A. Ram�rez, 2020. Trophic basis of production in tropical headwater streams, Puerto Rico: an assessment of the importance of allochthonous resources in fueling food webs. Hydrobiologia 847: 1961-1975.

Progress 02/05/19 to 09/30/19

Outputs
Target Audience:The primary audience for this research is academic. Research findings were presented at the academic meetings listed below. We presented poster and oral presentations that highlighted the importance of major findings in the project. International Congress of Odonatology, Autin, Texas Society for Freshwater Sciences annual meeting, Salt Lake City, Utah ASLO Annual meeting, Puerto Rico Our research is having a positive impact of minority training, in particular Hispanics. My lab has enrolled a student from Puerto Rico and undergraduate students from different minority groups and female students. We established communication with colleagues at the University of Puerto Rico and are sharing our main research findings with them. Internationally, we are collaborating with faculty at the University of Costa Rica. Professor Pablo Gutierrez is now a close collaborator of our research project. Thus helping us project our findings internationally. We are also working closely with colleagues in Mexico, at the Institute of Ecology in Xalapa, Veracruz. To promote our findings among the general society, we established a Facebook page (https://www.facebook.com/ARamirezLab/) to share research findings using accessible vocabulary and visual aids. Undergraduate and graduate students at NCSU are now actively participating in our projects. Six undergraduate students work in the lab on a regular basis and two graduate students are conducting their dissertation research in the context of our projects. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Our projects involve a number of students that are learning while conducting research. Two doctoral students at NCSU are participating of the projects in Costa Rica and Puerto Rico, developing ideas to design their dissertation work within the scope of the project. In addition, six undergraduate students had been participating of our lab work playing different roles, from technicians to field hands. All students are exposed to the various aspects of scientific research. They are also encouraged to pursue their own projects. We are collaborating with graduate students at the University of Puerto Rico and faculty at the University of Costa Rica to increase expose of our students and the impact of the project. How have the results been disseminated to communities of interest?We have presented our findings at international meetings, like those of the Society for Freshwater Science and the Association for the Sciences of Limnology and Oceanography. In addition, we have published our work in peer-reviewed journals, like Biotropical, Applied Ecology, and Freshwater Science. In social media, we have share main findings in plain language using our lab page in Facebook (https://www.facebook.com/ARamirezLab/) and our twitter account (@ARamirezLab). Findings are communicated with simple examples and had been well received by our audience. What do you plan to do during the next reporting period to accomplish the goals?We will continue conducting research toward achieving our goal of understanding of how stream ecosystems function in tropical and temperate environments and how they might be affected by predicted global changes. Graduate students will continue developing their thesis or disseration work within the scope of the project. We will be participating of national and international meetings to continue sharing our findings with the scientific community.

Impacts
What was accomplished under these goals? Overall, we did solid progress toward advancing our main goal of improving our understanding of how stream ecosystems function in tropical and temperate environments and how predicted global changes, urbanization, and other natural and anthropogenic stressor might affect them. Our research program in Costa Rica was focused on studying long-term trends in water chemistry and how they were affected by El Niño climate cycles. Long-term data sets were analyzed by graduate student Nicholas Marzolf and we are in the process of working on publications. Most of our work in Puerto Rico was designed towards understanding the effects of hurricanes Irma and Maria, that hit the island in 2017. Stream ecosystems were severely impacted by big floods due to all the precipitation and then by riparian vegetation removal due to strong winds during the hurricane. We are monitoring how stream ecosystems were impacted and their recovery trajectories. We have presented results at national and international meeting and are working on scientific publications. Given that Puerto Rico was affected by a major drought during 2015, we are also contrasting the effects of hurricanes with those measured for drought. Both event types are predicted to increase in frequency with changing climate. Our studies in urban streams were focused on understanding how urbanization affects stream biota. We studied mostly aquatic invertebrates (e.g., insects) and assessed how channel alteration and water pollution affects them. We presented results at national meetings and are working on two publications. We also focus on studying two groups of aquatic insects as model systems to understand how environmental stressors affect biota. We focus on dragonflies and their response to urbanization and small non-biting midges and their response to changes in pollution and water temperature. Both model organisms are promising to become useful tools in environmental monitoring. We have two graduate students working with them and presented preliminary results at scientific meetings.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Classen-Rodr�guez, L, Guti�rrez-Fonseca, PE, Ram�rez, A. 2019. Leaf litter decomposition and macroinvertebrate assemblages along an urban stream gradient in Puerto Rico. Biotropica 51: 641-651.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Kelly, S.P., E. Cuevas, & A. Ramirez. 2019. Urbanization increases the proportion of aquatic insects in the diets of riparian spiders. Freshwater Science 38(2): 379-390.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: McDowell, W.H., W.G. McDowell, J.D. Potter, & A. Ram�rez. 2019. Nutrient export and elemental stoichiometry in an urban tropical river. Ecological Applications, e01839.
• Type: Book Chapters Status: Published Year Published: 2019 Citation: R�os-Touma, B. & A. Ram�rez. 2019. Multiple Stressors in the Neotropical Region: Environmental Impacts in biodiversity hotspots. In: S. Sabater, A. Elosegi, & R. Ludwig (eds). Multiple Stressors in River Ecosystems. Elsevier, Cambridge, MA