Socioecological correlates of social play in adult mantled howler monkeys

The study of animal play is highly complex since its potential functions vary with social and environmental circumstances. Although play is generally characteristic of immature animals, it may persist in adults in its social form, particularly when interacting with young individuals, and less often with other adult playmates. We measured the amount of social play in 62 wild adult howler monkeys, Alouatta palliata, belonging to seven different groups in Mexico and Costa Rica. Overall, adult play represented a small mean proportion of observation time across all groups, but it was present in all study groups. Generalized linear mixed models revealed that group size correlated with both adult–adult and adult–immature play, supporting the hypothesis that more individuals provide more play opportunities. While play between adults decreased with increases in the immature to adult ratio, we did not find a clear preference for adults to play with immatures, emphasizing the importance of playing with other adult peers. Conversely, adults played more with immatures as the immature to adult ratio increased, which may correspond with the role adult–immature play may have in the socialization process of young individuals. More time dedicated to foraging on fruits corresponded with more adult–adult play. This finding, aside from being associated with more energy being available to engage in play, supports the hypothesis that play is a mechanism for solving conflicts associated with contest competition by either reducing social tension and/or fighting for a limited resource. The range of factors affecting social play indicates that this behaviour in adult howler monkeys is facultative, having affiliative, socializing and competitive roles, depending on the socioecological context

Heterogeneity and scaling of photosynthesis, respiration, and nitrogen uptake in three Atlantic Rainforest streams

Leaves, epilithon, macrophytes, and fine benthic organic material are central ecosystem compartments to food webs and mediate nutrient fluxes in streams. Most estimates of gross primary production (GPP) and ecosystem respiration (ER) are made at a reach scale, averaging across compartments. Thus, there is little information on how individual compartments contribute to and scale up to whole-stream estimates across watersheds. We compared estimates of GPP, ER, and nitrogen (N) uptake of individual ecosystem compartments (dm) and stream reaches (similar to 100 m) in three sizes of streams in a preserved Atlantic Rainforest watershed. The smallest stream had dense forest canopy cover, whereas the largest was more open. We measured substratum-specific rates of GPP and ER, as well as ammonium and nitrate N-15 uptake in recirculating chambers. We compared these decimeter-scale measurements to whole-stream estimates, using single-station dissolved oxygen (GPP and ER) and pulsed N uptake methods. Epilithon and macrophytes (when present) were the dominant GPP and N uptake compartments in open-canopy sites, and leaves contributed strongly to ER at all sites, even though they covered <3 percent of the stream bottom. Ammonium and nitrate uptake per unit N content varied significantly among substrata and streams. Upscaled inorganic N uptake per unit area was greater when macrophytes were present. Chamber measurements overestimated metabolic rates in the larger streams, but not in the smallest one. The smallest transient storage zone streams were more active than the biggest one, and this influenced the mismatch between whole-stream and chamber nutrient uptake estimates. We conclude that scaling to the whole watershed requires information on location in the watershed (e.g., where canopy cover is dense), rates of individual compartments, and reach-specific hydrodynamic information as influenced by large-scale geomorphic details (i.e., the size and activity of the transient storage zones)

Flow, nutrients, and light availability influence Neotropical epilithon biomass and stoichiometry

Light, nutrient availability, and flow are strong factors controlling the elemental composition and biomass of epilithon in temperate stream ecosystems. However, comparatively little is known about these relationships in tropical streams. We investigated how gradients of light and nutrient availability, seasonality, and habitat influenced epilithon biomass, chlorophyll a, and nutrient ratios in montane streams of Trinidad, West Indies. We sampled 4 focal tributaries of a single river, 2 of which had canopies experimentally thinned, every other month over a 2-y period to observe temporal dynamics and light effects on epilithon. We also sampled 18 sites across Trinidad’s Northern Range Mountains once each in a wet and dry season to examine the effects of naturally occurring differences in light and dissolved nutrient availability on epilithic characteristics. We found greater chlorophyll a concentrations in habitats with greater light availability, but the effect of light on epilithon stoichiometry differed between the site-survey and focal-tributary data. In general, epilithic C: nutrient ratios decreased with increasing dissolved nutrient concentrations, but relationships between nutrient availability and biomass probably were obscured by naturally high dissolved N and P concentrations in many of the streams. Season and habitat type had profound effects on epilithon variables. Biomass and % C generally decreased in riffles and under wet- season conditions. These results suggest multiple controls for the quantity and quality of stream epilithon and have important implications for in-stream consumers

Flow, nutrients, and light availability influence Neotropical epilithon biomass and stoichiometry

Light, nutrient availability, and flow are strong factors controlling the elemental composition and biomass of epilithon in temperate stream ecosystems. However, comparatively little is known about these relationships in tropical streams. We investigated how gradients of light and nutrient availability, seasonality, and habitat influenced epilithon biomass, chlorophyll a, and nutrient ratios in montane streams of Trinidad, West Indies. We sampled 4 focal tributaries of a single river, 2 of which had canopies experimentally thinned, every other month over a 2-y period to observe temporal dynamics and light effects on epilithon. We also sampled 18 sites across Trinidad’s Northern Range Mountains once each in a wet and dry season to examine the effects of naturally occurring differences in light and dissolved nutrient availability on epilithic characteristics. We found greater chlorophyll a concentrations in habitats with greater light availability, but the effect of light on epilithon stoichiometry differed between the site-survey and focal-tributary data. In general, epilithic C: nutrient ratios decreased with increasing dissolved nutrient concentrations, but relationships between nutrient availability and biomass probably were obscured by naturally high dissolved N and P concentrations in many of the streams. Season and habitat type had profound effects on epilithon variables. Biomass and % C generally decreased in riffles and under wet- season conditions. These results suggest multiple controls for the quantity and quality of stream epilithon and have important implications for in-stream consumers

Neotropical freshwater fisheries : A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The 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