Droughts are intensifying in the humid Neotropics, raising concerns about the impacts on ecosystem processes related to C cycling, such as decomposition and CO2 respiration. In particular, the resilience of multiple functions to extreme droughts in Neotropical aquatic systems remains poorly understood, limiting our ability to predict drought-driven feedbacks on C cycling. Here, we used rain shelters placed above tank bromeliads, plants that hold small freshwater ecosystems within their leaf axils, to emulate drought events ranging from the current norm to different IPCC scenarios. We then quantified the resilience of three key ecosystem functions (microbial respiration, litter decomposition, and photosynthetic efficiency) during a post-drought rewetting phase of 60 days. To assess the role of biotic recolonization during rewetting, we used mosquito nets over half of the bromeliads to prevent macroinvertebrates from recolonizing bromeliads from adjacent source patches. We found that extreme droughts (94 days) pushed heterotrophic functions above baseline levels during the rewetting phase. Microbial respiration and litter decomposition increased during this rewetting period, relative to undisturbed bromeliads. This boost was even faster when macroinvertebrate recolonization was allowed. Structural equation models suggested that nutrient release from dead organic matter during the rewetting phase, along with changes in bacterial density and shredder biomass, drove the positive shifts in heterotrophic functions and ecosystem multifunctionality. Extreme droughts accelerated C processing in tank bromeliads, particularly when external recolonization occurred, releasing a noticeable amount of carbon to the atmosphere. Our study shed light on the mechanisms underlying post-drought ecosystem multifunctionality trajectory and its link with C cycling, encouraging future works considering these small but abundant water bodies as sources of C in the Neotropics in the face of drought intensification.

Although tropical rainforest ants are abundant and have high species richness, with their community structure well known at the canopy and ground levels, the understory is frequently neglected. To fill this gap, we looked for ants nesting in this stratum in an Amazonian rainforest and noted the occurrence of colonies in the debris accumulated between the fronds of the palm tree Astrocaryum sciophilum or associated with eight myrmecophytes (i.e., plants that shelter ant colonies in hollow structures called domatia). We analysed these plant–ant relationships by conducting a network approach looking for the degree of specialisation between partners (specialisation index), the differences in intensity between links (weighted nestedness) and the proportion of realised interactions relative to the number of potential interactions (connectance), including ground‐ and canopy‐nesting ants. This results in a highly modular pattern of interactions with one module per plant species based on the 98 ant species recorded. We showed the importance of ground‐nesting species for Astrocaryum , although 40.5% of them sheltered a colony of the arboreal Odontomachus hastatus . Among myrmecophytes, a strong specificity was noted for Hirtella physophora (Chrysobalanaceae) and Maieta guianensis (Melastomataceae) that sheltered at more than 90% Allomerus decemarticulatus and Pheidole minutula , respectively. Cordia nodosa (Boraginaceae) has an intermediary value (45.3% associated with Allomerus octoarticulatus ), whereas Cecropia obtusa (Urticaceae), Duroia longiflora (Rubiaceae), Tachigali paniculata (Fabaceae) and Tococa guianensis (Melastomataceae) can shelter several ant species belonging mostly to a single genus. Tachia guianensis , considered a ‘non‐specialised’ myrmecophyte, shelters species from different genera.

Understanding the ecological responses of macroinvertebrates to multiple environmental drivers might be useful for assessing the health of freshwater ecosystems and providing managers with complementary bioindicators. In this study, the functional responses of macroinvertebrates in relation to spatiotemporal variability of the environmental features were surveyed along Oued Martil River basin (northwestern Morocco) during an annual cycle (spring, summer, autumn 2017 and winter 2018) at 20 sampling sites. Self-Organizing Maps (SOM) were used to determine spatio-temporal biotypology of macroinvertebrates functional feeding groups (FFGs) and to cluster the sampling sites under the combined effects of land use, physico-chemical and eco-hydrological variables analysed. The composition of FFGs differed significantly among sites and seasons. Our findings highlight that the abundance and taxa richness were higher in spring compared to the other seasons. Seven different clusters corresponded into natural, agricultural and urban land use were divided by the SOM based on their similarities to seasonal fluctuations of environmental variables. Then, Collectors-Gatherers were the most abundant and widespread group, while shredders were the most sensitive group across seasons along the longitudinal gradient of Oued Martil River basin. Overall, the results suggest that the ecological condition of the Oued Martil River basin exhibits a clear spatial pattern, ranging from relatively preserved upstream areas to anthropogenically impacted downstream sections.

ABSTRACT This study focuses on species occupying the three strata of an Amazonian rainforest: the ground and leaf litter, the understorey and the canopy. We employed only two sampling techniques: Winkler extraction for ground‐dwelling ants and direct observations for understorey and canopy species on large branches cut off by a climber. We identified 494 ant species from 10 subfamilies and 77 genera over ≈3.0 ha (Chao1 = 607 species; 95% CI: 566–670 species). Although we found fewer arboreal ants compared to approaches using insecticide fogging, this study confirms similarities between the ant diversity in Amazonian and Mesoamerican rainforests. The functional traits of these ants (i.e., diet, nest‐site preference, population size of the colony) allowed us to identify seven clusters. Cluster 1 is a “hodgepodge” grouping arboreal or ground‐dwelling species with different‐sized colonies (76 species). Cluster 2 primarily includes small colonies of ground‐nesting generalist feeders (142 species). Cluster 3 comprises all arboreal species from the understorey inhabiting myrmecophyte domatia or palm trees plus arboreal species with medium‐sized colonies (37 species). Cluster 4 includes all territorially dominant arboreal ants plus one ground‐dwelling species (21 species). All fungus‐growing species belong to Cluster 5, which also contains ground‐nesting generalist feeders and generalist predators (148 species). All doryline army ants are grouped in Cluster 6 along with one ponerine known for its nomadic behavior (15 species). Almost all specialized predators belong to Cluster 7 (55 species); however, Cluster 5 includes two ponerine species that prey exclusively on termites. Based on a nonmetric multidimensional scaling (NMDS), we confirmed that the position of these clusters corresponded fairly well to the three forest strata. Thus, analyzing functional traits enables the trophic position of most ants and their place in the vertical strata of Neotropical rainforests to be determined.

We aimed to determine how the degree of urbanization in a Neotropical city influences Aedes aegypti (L.), a pantropical vector of urban yellow fever, dengue, Zika and Chikungunia, via other mosquito species, whether they are competitors or predators, native to the area or invasive. We conducted experiments twice a month during one year in the city of Kourou, French Guiana, on three sites characterized by increasing percentages of imperviousness (i.e., 0.65

We studied variations in the volume of water stored in small lakes and wetlands using satellite remote sensing and lake water height data contributed by citizen scientists. A total of 94 water bodies across the globe were studied using satellite data in the optical and microwave wavelengths from Landsat 8, Sentinel-1, and Sentinel-2. The uncertainty in volume estimation as a function of geography and geophysical factors, such as cloud cover, precipitation, and water surface temperature, was studied. The key finding that emerged from this global study is that uncertainty is highest in regions with a distinct precipitation season, such as in the monsoon dominated South Asia or the Pacific Northwestern region of the USA. This uncertainty is further compounded when small lakes and wetlands are seasonal with alternating land use as a water body and agricultural land, such as the wetlands of Northeastern Bangladesh. On an average, 45% of studied lakes could be estimated of their volume change with a statistical significant uncertainty that is less than the expected volume in South Asia. In North America, this statistically significant uncertainty in volume estimation was found to be around 50% in lakes eastward of the 108th meridian with lowest uncertainty found in lakes along the East coast of the USA. The article provides a baseline for understanding the current state of the art in estimating volumetric change of lakes and wetlands using citizen science in anticipation of the recently launched Surface Water and Ocean Topography Mission.

The iconic fly Thyreophora cynophila has long attracted the interest of entomologists but, despite its re-discovery in Spain and France, its biology is still poorly known. The larvae and puparium have been described in detail but their feeding habits on large carcasses remain largely unknown. Here, we took advantage of a carrion pile containing the remains of wild boar (Sus scrofa) and red deer (Cervus elaphus) as well as of two cow (Bos taurus) carcasses to search for T. cynophila larvae inside the bones and skulls. We document the occurrence of T. cynophila inside the cerebral cavity of dead animals, containing the brain. From the carrion pile, out of seven skulls, T. cynophila larvae could be found in five of them, and identified on the basis of their size, the shape and arrangement of the ventral tubercles, prothoracic spiracle and cephalopharyngeal skeleton. In contrast, no T. cynophila larvae could be found inside the nine bones we inspected. From the cow carcasses, no T. cynophila larvae could be found in the bones but one larva was found inside the cerebral cavity of one cow. In addition, other Diptera and Coleoptera larvae were found inside the bones.

Host tree survey counts 1. Presentation of the data gathered from 10 x 5 m plots along the road leading to Petit Saut. Every horizontal lines is highlited for readlability; the vertical lines 2. Pesentation of the data gathered from 10 x 5 m plots near Régina over 90 m on Route 2 around kilometric point 118

The impact of climate change is intensifying in Amazonia through, among other causes, the higher frequency of both severe droughts and floods due to El Nino and La Nina events as well as an Atlantic influence. Over a 25-year period (1997-2021) we examined in French Guiana the impact of different climatic parameters on the most frequent social wasp, Polybia bistriata (Polistinae). As it commonly nests on Clusia grandiflora (Clusiaceae), its nests are easily found. Heavy rainfall, particularly during the 1999-2000 La Nina episode, negatively affected this social wasp species as the percentage of Clusia sheltering an active P. bistriata nest decreased from approximate to 40% during the pre-2000 period to zero in 2021. We conclude that extreme wet seasons related to climate change translated into the decline of this species and likely were detrimental to many other polistine wasps of north-eastern Amazonia.

In Amazonia higher Atlantic sea surface temperatures, greenhouse gasses, deforestation and El Nifio events result in the greater frequency of severe droughts, although total rainfall has increased due to wetter rainy seasons, something confirmed in French Guiana from available climatic data (1980-2017). Aiming to study the impact of rainfall on ant gardens (i.e., arboreal ant-epiphyte mutualisms that depend on the atmosphere for water; AGs) initiated by the ponerine ant Neoponera goeldii, we conducted surveys around the Petit Saut and Regina areas (mean annual rainfall: approximate to 3,000 mm and approximate to 4,000 mm, respectively). Each year, near the end of the dry season we recorded the number of these AGs in 10 x 5 m sections parallel to the roadsides. The Petit Saut survey (1993-2017) revealed that AG density along roadsides varied only slightly in "wet zones" situated along ditches, whereas in "dry zones" where the soil seasonally dries out it dropped sharply during the drastic 1997 dry season. Then, this density, low due to recurrent droughts, dropped again during the drastic successive 2015-2016 dry seasons. In the Regina survey (2006-2017), we had the opportunity to follow the establishment of AGs in a "dry zone". It was represented by a typical sigmoidal curve and then it stabilized with AG densities higher than at its peak in 1996 in dry zones of Petit Saut, showing the importance of rainfall. Here, too, the drastic 2016 dry season adversely affected the AGs. Finally, the epiphytic composition of the AGs was mainly represented by Aechmea mertensii (a tank bromeliad), Anthurium gracile (Araceae) and Codonanthe crassifolia (Gesneriaceae), but AGs with the tank bromeliad are more resistant to droughts. These AGs are at risk in dry zones if drastic successive dry seasons occur in the future as global warming intensifies while those developing in riparian areas might survive. (C) 2022 Published by Elsevier GmbH on behalf of Gesellschaft fur Okologie.

The predicted increase in the intensity and frequency of drought events associated with global climate change will impose severe hydrological stress to freshwater ecosystems, potentially altering their structure and function. Unlike freshwater communities’ direct response to drought, their post-drought recovery capacities remain understudied despite being an essential component driving ecosystem resilience. Here we used tank bromeliad as model ecosystem to emulate droughts of different duration and then assess the recovery capacities of ecosystem structure and function. We followed macroinvertebrate predator and prey biomass to characterize the recovery dynamics of trophic structure (i.e. predator–prey biomass ratio) during the post-drought rewetting phase. We showed that drought significantly affects the trophic structure of macroinvertebrates by reducing the predator–prey biomass ratio. The asynchronous recovery of predator and prey biomass appeared as a critical driver of the post-drought recovery trajectory of trophic structure. Litter decomposition rate, which is an essential ecosystem function, remained stable after drought events, indicating the presence of compensatory effects between detritivores biomass and detritivores feeding activity. We conclude that, in a context of global change, the asynchrony in post-drought recovery of different trophic levels may impact the overall drought resilience of small freshwater ecosystems in a more complex way than expected.

Ants are a major ecological group in tropical rainforests. Few studies in the Neotropics have documented the distribution of ants from the ground to the canopy, and none have included the understorey. A previous analysis of an intensive arthropod study in Panama, involving 11 sampling methods, showed that the factors influencing ant beta diversity (i.e., changes in assemblage composition) were, in decreasing order of importance, the vertical (height), temporal (season), and horizontal (geographic distance) dimensions. In the present study, we went one step further and aimed (1) to identify the best sampling methods to study the entire ant assemblage across the three strata, (2) to test if all strata show a similar horizontal beta diversity and (3) to analyze the functional structure of the entire ant assemblage. We identified 405 ant species from 11 subfamilies and 68 genera. Slightly more species were sampled in the canopy than on the ground; they belonged to distinct sub-assemblages. The understorey fauna was mainly a mixture of species found in the other two strata. The horizontal beta diversity between sites was similar for the three strata. About half of the ant species foraged in two (29%) or three (25%) strata. A single method, aerial flight interception traps placed alongside tree trunks, acting as arboreal pitfall traps, collected half of the species and reflected the vertical stratification. Using the functional traits approach, we observed that generalist species with mid-sized colonies were by far the most numerous (31%), followed by ground- or litter-dwelling species, either specialists (20%), or generalists (16%), and arboreal species, either generalists (19%) or territorially dominant (8%), and finally army ants (5%). Our results reinforce the idea that a proper understanding of the functioning of ant assemblages requires the inclusion of arboreal ants in survey programs.

While future climate scenarios predict declines in precipitations in many regions of the world, little is known of the mechanisms underlying community resilience to prolonged dry seasons, especially in 'naïve' Neotropical rainforests. Predictions of community resilience to intensifying drought are complicated by the fact that the underlying mechanisms are mediated by species' tolerance and resistance traits, as well as rescue through dispersal from source patches. We examined the contribution of in situ tolerance-resistance and immigration to community resilience, following drought events that ranged from the ambient norm to IPCC scenarios and extreme events. We used rainshelters above rainwater-filled bromeliads of French Guiana to emulate a gradient of drought intensity (from 1 to 3.6 times the current number of consecutive days without rainfall), and we analysed the post-drought dynamics of the taxonomic and functional community structure of aquatic invertebrates to these treatments when immigration is excluded (by netting bromeliads) or permitted (no nets). Drought intensity negatively affected invertebrate community resistance, but had a positive influence on community recovery during the post-drought phase. After droughts of 1 to 1.4 times the current intensities, the overall invertebrate abundance recovered within invertebrate life cycle durations (up to 2 months). Shifts in taxonomic composition were more important after longer droughts, but overall, community composition showed recovery towards baseline states. The non-random patterns of changes in functional community structure indicated that deterministic processes like environmental filtering of traits drive community re-assembly patterns after a drought event. Community resilience mostly relied on in situ tolerance-resistance traits. A rescue effect of immigration after a drought event was weak and mostly apparent under extreme droughts. Under climate change scenarios of drought intensification in Neotropical regions, community and ecosystem resilience could primarily depend on the persistence of suitable habitats and on the resistance traits of species, while metacommunity dynamics could make a minor contribution to ecosystem recovery. Climate change adaptation should thus aim at identifying and preserving local conditions that foster in situ resistance and the buffering effects of habitat features.

Macromia splendens is a rare species, endemic to southern France and the Iberian Peninsula. Information about its larval ecology is still scarce. For the first time, we have obtained 30 photographic and video records of M. splendens larvae in natura from three small rivers in southern France and we comment on these observations. Our observations confirm that M. splendens larvae live in shady places and hide in a covering of brown detritus, consisting of leaves and sticks, as indicated by previous studies. However, our observations show that larvae are also present in open micro -habitats, exposing them to trampling by bathers or horses.

Aquatic ecosystems are exposed to multiple stressors such as agricultural run-off (ARO) and climate-change related increase of temperature. We aimed to determine how ARO and the frequency of its input can affect shallow lake ecosystems through direct and indirect effects on primary producers and primary consumers, and whether warming can mitigate or reinforce the impact of ARO. We performed a set of microcosm experiments simulating ARO using a cocktail of three organic pesticides (terbuthylazine, tebuconazole, pirimicarb), copper and nitrate. Two experiments were performed to determine the direct effect of ARO on primary producers (submerged macrophytes, periphyton and phytoplankton) and on the grazing snail Lymnaea stagnalis, respectively. Three different ARO concentrations added as single doses or as multiple pulses at two different temperatures (22°C and 26°C) were applied. In a third experiment, primary producers and consumers were exposed together to allow trophic interactions. When functional groups were exposed alone, ARO had a direct positive effect on phytoplankton and a strong negative effect on L. stagnalis. When exposed together, primary producer responses were contrasting, as the negative effect of ARO on grazers led to an indirect positive effect on periphyton. Periphyton in turn exerted a strong control on phytoplankton, leading to an indirect negative effect of ARO on phytoplankton. Macrophytes showed little response to the stressors. Multiple pulse exposure increased the effect of ARO on L. stagnalis and periphyton when compared with the same quantity of ARO added as a single dose. The increase in temperature had only limited effects. Our results highlight the importance of indirect effects of stressors, here mediated by grazers and periphyton, and the frequency of the ARO input in aquatic ecosystems.

The intensification of dry seasons is a major threat to freshwater biodiversity in Neotropical regions. Little is known about resistance to drying stress and the underpinning traits in Neotropical freshwater species, so we don't know whether desiccation resistance allows to anticipate shifts in biological diversity under future climate scenarios. Here, we used the aquatic invertebrates that live in the rainwater-filled leaves of tank bromeliads, to examine the extent to which desiccation resistance of species measured in the laboratory predicts community response to drought intensification in nature. We measured desiccation resistance in 17 invertebrate species (> 90% of the biomass usually found in bromeliads of French Guiana) by recording the median lethal time (LT50) of experimental populations exposed to controlled conditions of residual moisture. In the field, we placed rainshelters above tank bromeliads to emulate drought scenarios ranging from the ambient norm to IPCC scenarios and extreme events, and we recorded the response of functional community structure. LT50 ranged from 4.18 to 19.06 days, and was related to cuticle content and dry body mass. Among other functional indicators that represent strategies to optimize resource use under stressful conditions (e.g., habitat use, trophic specialization), LT50 was the best predictor of community structure responses along a gradient of emulated drought intensities. Therefore, species' LT5Os measured under laboratory conditions can be used to forecast aquatic community response to drying stress in nature. Anticipating how species will cope with drought has never been more important for environmental managers to support climate change adaptation. We show that desiccation resistance in freshwater invertebrates is a key indicator of potential population size and local-global range shifts, and this could be especially true in the Neotropics where species have narrow physiological tolerances for climatic variation.

1. Ants are widespread in tropical rainforests, including in the canopy where territorially dominant arboreal species represent the main part of the arthropod biomass.2. By mapping the territories of dominant arboreal ant species and using a null model analysis and a pairwise approach this study was able to show the presence of an ant mosaic on the upper canopy of a primary Neotropical rainforest (c. 1 ha sampled; 157 tall trees from 28 families). Although Neotropical rainforest canopies are frequently irregular, with tree crowns at different heights breaking the continuity of the territories of dominant ants, the latter are preserved via underground galleries or trails laid on the ground.3. The distribution of the trees influences the structure of the ant mosaic, something related to the attractiveness of tree taxa for certain arboreal ant species rather than others.4. Small‐scale natural disturbances, most likely strong winds in the area studied (presence of canopy gaps), play a role by favouring the presence of two ant species typical of secondary formations: Camponotus femoratus and Crematogaster levior, which live in parabiosis (i.e. share territories and nests but lodge in different cavities) and build conspicuous ant gardens. In addition, pioneer Cecropia myrmecophytic trees were recorded.

In Neotropical rainforest canopies, phytotelmata ("plant-held waters") shelter diverse aquatic macroinvertebrate communities, including vectors of animal diseases. Studying these communities is difficult because phytotelmata are widely dispersed, hard to find from the ground and often inaccessible. We propose here a method for placing in tree crowns "artificial phytotelmata" whose size and shape can be tailored to different research targets. The efficacy of this method was shown while comparing the patterns of community diversity of three forest formations. We noted a difference between a riparian forest and a rainforest, whereas trees alongside a dirt road cutting through that rainforest corresponded to a subset of the latter. Because rarefied species richness was significantly lower when the phytotelmata were left for three weeks rather than for six or nine weeks, we recommend leaving the phytotelmata for twelve weeks to permit predators and phoretic species to fully establish themselves.