Friedrich Wolfgang Keppeler
@wisc.edu
UW Madison
RESEARCH, TEACHING, or OTHER INTERESTS
Ecology, Evolution, Behavior and Systematics, Aquatic Science
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Gustavo Hallwass, Friedrich W. Keppeler, Luís H. Tomazoni-Silva, Ivan A. Alves, Victoria J. Isaac, Morgana C. Almeida, and Renato A. M. Silvano
Springer Science and Business Media LLC
Marcelo C. Andrade, Friedrich W. Keppeler, Mario Alejandro Zuluaga-Gómez, Jefferson W. S. Conceição, Oliver P. Lisboa, Ryan Andrades, Kirk Winemiller, and Tommaso Giarrizzo
Springer Science and Business Media LLC
Yasmín Quintana, Friedrich Wolfgang Keppeler, and Kirk O. Winemiller
Wiley
AbstractPopular as aquarium fish, armored catfishes from South America (Pterygoplichthys spp.) have been introduced and become invasive in tropical and subtropical regions worldwide. These ecosystem engineers can deplete basal resources (e.g., periphyton and detritus), with potential negative effects for native fauna. We studied the trophic ecology of fishes in the Usumacinta River Basin, Guatemala, where Pterygoplichthys is now widespread and locally abundant. We analyzed stable isotopes (δ13C, δ15N) in fish tissues and basal resources to assess the potential impact of Pterygoplichthys on the trophic ecology of six co‐occurring native fishes that feed at a similar trophic level (Astyanax aeneus, Dorosoma petenense, Thorichthys pasionis, Oscura heterospila, Poecilia mexicana, and Gambusia sexradiata). The study was conducted during the dry season in the La Pasion (LPR; high invasion) and San Pedro (SPR; low invasion) rivers. We compared isotopic spaces occupied by native fish and Pterygoplichthys, estimated isotopic overlap, and evaluated the trophic displacement of native species. We also evaluated the relationships of environmental factors, including the relative biomass of the invasive catfish, with δ13C and δ15N signatures. Except for P. mexicana, native species had lower isotopic overlap with the catfish in LPR. Native fish isotopic spaces were compressed and shifted toward higher trophic positions in LPR relative to SPR. Benthic food resources were important for Pterygoplichthys in both rivers, and water‐column resources had greater relative importance (RI) for native species in LPR. Native fish δ13C was significantly associated with Pterygoplichthys biomass, conductivity, and water flow velocity; and water depth and sedimentation had a significant association with native fish δ15N. Findings provide evidence that invasive Pterygoplichthys, along with environmental factors, impact the trophic ecology of native fish in the Usumacinta Basin. Additional field research conducted over longer time periods and mesocosm experiments that account for fish assemblage and environmental variation could elucidate Pterygoplichthys impacts via food resource depletion or habitat alteration.
Lívia Helena Tonella, Renata Ruaro, Vanessa Salete Daga, Diego Azevedo Zoccal Garcia, Oscar Barroso Vitorino, Tatiana Lobato‐de Magalhães, Roberto Esser dos Reis, Fabio Di Dario, Ana Cristina Petry, Michael Maia Mincarone,et al.
Wiley
AbstractThe Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large‐scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications.
Friedrich W. Keppeler, James R. Junker, Margaret J. Shaw, Scott B. Alford, Annette S. Engel, Linda M. Hooper‐Bùi, Olaf P. Jensen, Katelyn Lamb, Paola C. López‐Duarte, Charles W. Martin,et al.
Wiley
AbstractCoastal wetlands are rapidly disappearing worldwide due to a variety of processes, including climate change and flood control. The rate of loss in the Mississippi River Delta is among the highest in the world and billions of dollars have been allocated to build and restore coastal wetlands. A key question guiding assessment is whether created coastal salt marshes have similar biodiversity to preexisting, reference marshes. However, the numerous biodiversity metrics used to make these determinations are typically scale dependent and often conflicting. Here, we applied ecological theory to compare the diversity of different assemblages (surface and below‐surface soil microbes, plants, macroinfauna, spiders, and on‐marsh and off‐marsh nekton) between two created marshes (4–6 years old) and four reference marshes. We also quantified the scale‐dependent effects of species abundance distribution, aggregation, and density on richness differences and explored differences in species composition. Total, between‐sample, and within‐sample diversity (γ, β, and α, respectively) were not consistently lower at created marshes. Richness decomposition varied greatly among assemblages and marshes (e.g., soil microbes showed high equitability and α diversity, but plant diversity was restricted to a few dominant species with high aggregation). However, species abundance distribution, aggregation, and density patterns were not directly associated with differences between created and reference marshes. One exception was considerably lower density for macroinfauna at one of the created marshes, which was drier because of being at a higher elevation and having coarser substrate compared with the other marshes. The community compositions of created marshes were more dissimilar than reference marshes for microbe and macroinfauna assemblages. However, differences were small, particularly for microbes. Together, our results suggest generally similar taxonomic diversity and composition between created and reference marshes. This provides support for the creation of marsh habitat as tools for the maintenance and restoration of coastal biodiversity. However, caution is needed when creating marshes because specific building and restoration plans may lead to different colonization patterns.
Kirk O. Winemiller, Marcelo C. Andrade, Caroline C. Arantes, Thethela Bokhutlo, Luke M. Bower, Eduardo R. Cunha, Friedrich W. Keppeler, Edwin O. López-Delgado, Yasmin Quintana, David E. Saenz,et al.
Elsevier BV
Friedrich W. Keppeler, Annette S. Engel, Linda M. Hooper‐Bùi, Paola C. López‐Duarte, Charles W. Martin, Jill A. Olin, Katelyn J. Lamb, Michael J. Polito, Nancy N. Rabalais, Brian J. Roberts,et al.
Wiley
Advancing ecological restoration assessments requires a more detailed consideration of species interactions and ecosystem processes. Most restoration projects rely on a few metrics not always directly linked with ecological theory. Here, we used Odum's theory of ecosystem development to assess and compare the ecosystem structure and services of created marshes (4–6 years old) with preexisting, reference marshes in a brackish water region of the Mississippi River Delta. We built ecosystem models for created and reference marshes that integrated large datasets of stomach contents, stable isotopes, and taxa abundances. Despite strong resemblance in community structure, created marshes were at an earlier succession stage compared to the reference marshes, having lower biomass (including exploited species), higher biomass turnover and production, less dependence on detritus, lower material cycling, and less energy flowing through specialist pathways. Although preserving preexisting marshes should be a priority, created marshes may still be an important tool for the restoration of coastal areas and their ecosystem services. In addition, our results show that comparisons of species biodiversity alone may fail to capture essential differences in ecosystem processes between habitats, which reinforces the importance of ecosystem modeling approaches to assess restoration projects.
Fábio Renan Miranda da Silva, Eurico Mesquita Noleto Filho, Maria Luiza Gallina, Friedrich Wolfgang Keppeler, Miguel Loiola, Tommaso Giarrizzo, and José Amorim Reis-Filho
Frontiers Media SA
The knowledge held by local and indigenous communities has been recognized as an invaluable yet underused resource for understanding how the environment, local conditions, and fish populations change over time. Empirical information on population sizes, ecology, and threats to fish species and their habitats can be complemented with local knowledge to better guide management and conservation efforts, particularly for understudied species. Here, we investigated the habitat preferences, population status, fishing, sightings patterns, threats, and habitat characteristics of juveniles of the cubera snapper, the largest snapper in the Atlantic Ocean. We used a combination of empirical evidence from underwater surveys by using small-action cameras and an ethnological perspective based on fishers’ perceptions who are cubera-snapper fishing specialists to have a comprehensive understanding of the species and habitat use during its early life stages. A range of estuarine habitats was examined over a year to assess the association between cubera snapper juveniles and different estuarine characteristics and conservation scenarios. Both sources of data indicated that cubera snapper juveniles heavily rely on mangrove habitats, exhibiting a clear temporal pattern of residence within these habitats. However, the probability of occurrence varied based on the level of coastal development in each estuarine system. Estuaries with small drainage areas, directly connected to the ocean, and presenting larger mangrove areas accounted for the highest abundances of juveniles. Factors such as mangrove removal, overfishing, and water pollution significantly reduced the occurrence and reliance of cubera snapper juveniles in the studied estuaries. The study represents the first attempt to shed light on the ecological aspects of cubera snapper juveniles, addressing a gap in their life cycle. It underscores the importance of integrating complementary sources of evidence to understand the relationships between the crucial life stage of cubera snappers, their habitats, and the threats they face. The ecological and ethnographic knowledge gained from this research should be incorporated into biomonitoring and conservation policy to effectively preserve this vulnerable top predator.
Friedrich W. Keppeler, Marcelo C. Andrade, Paulo A.A. Trindade, Leandro M. Sousa, Caroline C. Arantes, Kirk O. Winemiller, Olaf P. Jensen, and Tommaso Giarrizzo
Elsevier BV
Paulo Arthur A. Trindade, Juliana S. Araújo, Valter M. Azevedo-Santos, Friedrich W. Keppeler, Tommaso Giarrizzo, and Philip M. Fearnside
American Association for the Advancement of Science (AAAS)
Description
Carmen G. Montaña, Friedrich W. Keppeler, Clay P. Laughrey, and Christopher M. Schalk
Springer Science and Business Media LLC
Friedrich W. Keppeler, Jill A. Olin, Paola C. López‐Duarte, Michael J. Polito, Linda M. Hooper‐Bùi, Sabrina S. Taylor, Nancy N. Rabalais, F. Joel Fodrie, Brian J. Roberts, R. Eugene Turner,et al.
Wiley
AbstractBody size is considered an important structuring mechanism of food webs because consumers are usually larger and more mobile than their prey and may couple energy among habitats. We explored the links among trophic position (TP), body size, and the coupling of different energy channels (phytoplankton and C4‐marsh plants) in a saltmarsh landscape in the northern Gulf of Mexico—a dynamic system considered weakly shaped by biotic interactions. Body size was positively associated with TP, and this relationship was stronger in the phytoplankton pathway vs. the C4‐marsh pathway. There was a gradual increase in the coupling of phytoplankton and C4‐marsh plants at larger body sizes and higher TP. Phytoplankton supported longer food chains and larger body sizes than C4‐marsh plants. Results support predictions of the landscape theory for food web architecture and indicate that the role of body size in determining trophic interactions may vary across food web compartments.
Thethela Bokhutlo, Friedrich W. Keppeler, and Kirk O. Winemiller
Springer Science and Business Media LLC
Leonardo Capitani, Ronaldo Angelini, Friedrich Wolfgang Keppeler, Gustavo Hallwass, and Renato Azevedo Matias Silvano
Springer Science and Business Media LLC
Friedrich W. Keppeler, Carmen G. Montaña, and Kirk O. Winemiller
Wiley
AbstractPredators typically are larger than their prey, and consequently, trophic level should increase with body size. Whereas this relationship has helped in developing predictions about food web structure and dynamics in mesocosms and simple communities, a trophic‐level–body‐size relationship may not exist for all kinds of communities or taxa, especially those with many non‐carnivorous species. Moreover, functional traits associated with trophic level generally have not been considered. Herein, we examine the correlation between trophic level and body size in fishes and how this relationship may vary in relation to functional traits (body dimensions, mouth size and orientation, tooth shape, gill rakers, and gut length) and trophic guilds (carnivorous vs. non‐carnivorous). We analyzed data from morphological measurements and dietary analyses performed on thousands of specimens from freshwater and estuarine habitats across three zoogeographic regions (Neartic, Neotropical, and Afrotropical). A positive relationship between trophic level and body size was only found for carnivorous fishes. No relationship was found when all species were analyzed together, rejecting the idea that trophic level is positively related with body size in fishes generally. This result was consistent even when using either body mass or standard length as the measure of body size, and trophic level for either species (average values) or individual specimens as the response variable. At the intraspecific level, trophic level varied consistently with size for one third of the species, among which only 40% had positive relationships. Body depth, tooth shape, and mouth width were all associated with the trophic‐level–body‐size relationship. Overall, predators with conical or triangular serrated teeth, large mouths, and elongated/and/or fusiform bodies tend to have positive trophic‐level–body‐size relationships, whereas primarily non‐carnivorous species with unicuspid or multicuspid teeth, deep bodies and small to medium sized mouth gapes tended to have negative relationships. Given the diverse ecological strategies encompassed by fishes, trophic level and food web patterns and processes should not be inferred based solely on body size. Research that integrates multiple functional traits with trophic ecology will improve understanding and predictions about food web structure and dynamics.
Friedrich Wolfgang Keppeler and Kirk O. Winemiller
Springer Science and Business Media LLC
Friedrich Wofgang Keppeler, Gustavo Hallwass, Franciele Santos, Luís Henrique Tomazzoni da Silva, and Renato Azevedo Matias Silvano
Elsevier BV
Friedrich W. Keppeler and Kirk O. Winemiller
Wiley
AbstractSpecies interactions are difficult to quantify, and, consequently, many studies have used species traits and phylogeny as proxies under an assumption of niche conservatism (i.e., closely related and morphologically similar species should have similar niches). However, few studies have investigated whether niches actually are conserved within and across diverse communities. Here, we tested the degree to which phylogenetic relatedness and morphological similarity predict diets and stable isotopic ratios (δ15N and δ13C), two common descriptors of the trophic niche, in fish assemblages of two small streams in the Neotropics. We also tested the strength of the association between isotopic ratios and diet composition and found significant correlations implying that isotopic signals reveal trophic structure despite error associated with estimates of trophic enrichment and variation associated with tissue preservation, metabolism, and other factors affecting isotopic ratios. Morphological traits yielded a significant phylogenetic signal, and both morphological traits and phylogeny were correlated with diet composition, with morphological traits being a stronger predictor. We infer that functionally relevant morphological traits of fish can be used to infer trophic niches for certain kinds of questions and analyses when trophic data are lacking. However, we highlight that using phylogenetic and morphological data in combination with dietary and/or isotopic data can improve resolution of assemblage trophic structure and niche diversification.
Carmen G. Montaña, Chouly Ou, Friedrich W. Keppeler, and Kirk O. Winemiller
Springer Science and Business Media LLC
Gustavo Hallwass, Pedro Peixoto Nitschke, and Friedrich W. Keppeler
Springer International Publishing
Friedrich W. Keppeler and Renato A. M. Silvano
Springer International Publishing
Renato A. M. Silvano, Pedro P. Nitschke, Kaluan C. Vieira, Paula Nagl, Astrid T. R. Martínez, Márcia C. F. Dutra, Friedrich W. Keppeler, Junior A. Chuctaya, Henrique N. Oliveira, and Marcelo C. Andrade
Springer International Publishing
Renato A. M. Silvano, Pedro P. Nitschke, Kaluan C. Vieira, Paula Nagl, Astrid T. R. Martínez, Márcia C. F. Dutra, Friedrich W. Keppeler, Junior A. Chuctaya, and Marcelo C. Andrade
Springer International Publishing
Renato A. M. Silvano, Pedro P. Nitschke, Kaluan C. Vieira, Paula Nagl, Astrid T. R. Martínez, Junior A. Chuctaya, Márcia C. F. Dutra, Friedrich W. Keppeler, Anaís R. P. Rowedder, and Marcelo C. Andrade
Springer International Publishing
Friedrich W. Keppeler, Eduardo R. Cunha, and Kirk O. Winemiller
Hindawi Limited
Fin clips have been proposed as a non‐lethal and non‐invasive alternative to dorsal muscle samples in stable isotope analysis. However, potential differences in elemental composition and turnover rates can bias inferences when different tissues are combined. Here, we tested the average difference and correlation of the isotopic signature of δ¹³C and δ¹⁵N between muscle and fin samples in two arge‐bodied fishes: Longnose Gar (Lepisosteus osseus) and Smallmouth Buffalo (Ictiobus bubalus). We found that δ¹⁵N signatures of muscle and fin tissues were strongly and positively correlated for both species, although the muscle tissue for Smallmouth Buffalo was slightly more enriched in δ15N. δ¹³C signatures of both tissues were significatively different and not strongly correlated for Longnose Gar, but similar and strongly correlated for Smallmouth Buffalo. Our results suggest that fin and muscle tissue can be combined for analyses of δ¹⁵N, but correction for higher enrichment of muscle tissue may be necessary for Smallmouth Buffalo. Conversely, combining fin and muscle tissue for analysis of δ¹³C requires more caution due to their weaker correlation and dependence of species identity.