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opennotspecifiedMar 2014View details →

Figure 3 in A review of the Distichodus antonii assemblage (Characiformes: Distichodontidae) from the Congo basin

Figure 3. Illustrations of type specimens of the Distichodus antonii assemblage. (A) Holotype of D. antonii (BMNH 1899.9.6.10), 103.3 mm SL; (B) Lectotype of Distichodus fasciolatus (MRAC 23), 278.2 mm SL; (C) Holotype of Distichodus langi (AMNH 5915), 364 mm SL. Picture taken by M.L.J. Stiassny (AMNH); (D) Syntype of Distichodus atroventralis (BMNH 1891.12.29.13), 63.5 mm SL.

opennotspecifiedMar 2014View details →

Figure 9 in A review of the Distichodus antonii assemblage (Characiformes: Distichodontidae) from the Congo basin

Figure 9. Scatterplots of HL (mm) against head depth (% HL) for specimens identified as Distichodus mossambicus from: (○) Lower Congo; (●) Kasai and (■) Zambezi.

opencc-zeroDec 2021View details →

Chironomid assemblages and inferred summer temperature, late Rissian, Eemian and earliest Würmian, S Germany

The data herein presents a new chironomid record and associated chironomid-based temperature reconstruction covering the mid Eemian to the end of the first Würmian stadial (ca. 125–105 ka), augmented by results for the late Rissian glaciation and the early Brörup interstadial from the Füramoos palaeolake, southern Germany. There is an unconformity in the sediment core analysed between the late Rissian sediments and the mid Eemian sediments. These data also include non-chironomid invertebrate remains, including Ceratopogonidae, Daphnia and Ephemeroptera as well as Characean oospores.

opencc-zeroDec 2021View details →

Macronutrient niches and field limitation in a woodland assemblage of harvestmen

1. Description of animals' trophic niches help us understand interactions between species in biological communities that are not easily observed. Analyses of macronutrient niches, i.e. the range of macronutrient (protein:lipid:carbohydrate) ratios selected by generalist feeders, may be a useful alternative approach to inter-species comparisons of diets, especially within taxonomic assemblages of predators where species with similar nutritional requirements are likely to accept similar types of prey. 2. Here we analysed the macronutritional niches of a woodland assemblage of seven harvestman species, all supposed to be predators with omnivorous tendencies. Five species (Mitopus morio, Leiobunum gracile, Oligolophus tridens, O. hanseni, Paroligolophus agrestis) were native and two species (Opilio canestrinii, Dicranopalpus ramosus) were recent invaders into the community. 3. We compare the fundamental (FMN) and realized (RMN) macronutritional niche positions of the species using a 'double-test procedure', which provides information on whether the species were food limited in their natural habitat, and whether they were limited by specific macronutrients. 4. All seven species were food limited and six species were non-protein limited in the field; of these, four species were carbohydrate limited, and in one species females were lipid limited and males carbohydrate limited. These findings add to the notion that predators are mainly non-protein limited in the field. 5. The FMN positions of the assemblage fell within 46-50% protein, 29-38% lipid, and 16-22% carbohydrate. The amount of carbohydrate in the self-selected diet combined with carbohydrate limitation confirms that the species are zoophytophagous. Two morphological clusters of species (large long-legged vs. small short-legged species) differed not only in microhabitat (upper vs. lower forest strata) but also in macronutrient selection, where large long-legged species selected higher proportion of carbohydrate than small short-legged species. Thus, morphologically similar species occupy the same habitat stratum and have similar macronutritional niches. 6. We discuss the hypothesis that the invasive O. canestrinii might have an impact on native species as it allegedly had in urban environments previously. Two basic assumptions about interspecific resource competition were fulfilled, i.e. high overlap of nutritional requirements and limitation by food and macronutrients.

opencc-zeroDec 2021View details →

Forest spider data to study the response of assemblages to regional and local processes

Understanding species richness variation among local communities is one of the central topics in ecology, but the complex interplay of regional processes, environmental filtering and local processes hampers generalization on the importance of different processes. Here, we aim to unravel drivers of spider community assembly in temperate forests by analyzing two independent data sets covering gradients in elevation and forest succession. We test the following four hypotheses: (H1) Spider assemblages within a region are limited by dispersal; (H2) Local environment has a disproportionate influence on species composition; and (H3) resources and (H4) biotic interactions both affect species richness patterns. Spider data were collected by pitfall traps in two independent projects within a region along elevation and canopy cover gradients.

Fungal fruit body assemblages are tougher in harsh microclimates

Forest species are affected by macroclimate, however, the microclimatic variability can be more extreme and change through climate change. Fungal fruiting community composition was affected by microclimatic differences. Here we ask whether differences in the fruiting community can be explained by morphological traits of the fruit body, which may help endure harsh conditions. We used a dead wood experiment and macrofungal fruit body size, color, and toughness. We exposed logs of two host tree species under closed and experimentally opened forest canopies in a random-block design for four years and identified all visible fruit bodies of two fungal lineages (Basidio- and Ascomycota). We found a consistently higher proportion of tough-fleshed species in harsher microclimates under open canopies. Although significant, responses of community fruit body size and color lightness were inconsistent across lineages. We suggest the toughness-protection hypothesis, stating that tough-fleshed fruit bodies protect from microclimatic extremes by reducing dehydration. Our study suggests that the predicted increase of microclimatic harshness with climate change will likely decrease the presence of soft-fleshed fruit bodies. Whether harsh microclimates also affect the mycelium of macrofungi with different fruit body morphology would complement our findings and increase predictability under climate change.

Beta diversity of aquatic macroinvertebrate assemblages associated with leaf patches in neotropical montane streams

Over 70% of the total channel length in all river basins is formed by low order streams, many of which originate on mountaintops. Headwater streams play fundamental roles in processing and transporting terrestrial and aquatic organic matter, often harboring high biodiversity in bottom leaf patches deposited from riparian vegetation. The objective of this study was to assess the variation in taxonomic composition (measured by beta diversity of aquatic macroinvertebrates) among stream sites located in the Espinhaço Meridional Mountain Range, part of a UNESCO Biosphere Reserve in eastern Brazil. We tested two hypotheses. i) Taxa turnover is the main reason for differences in aquatic insect assemblages within stream sites; we predicted that turnover would be higher than nestedness in all stream sites. ii) Stream site altitude and catchment elevation range are the main explanatory variables for the differences in beta diversity; we predicted that local stream site variables would account for only minor amounts of variation. In both dry and wet seasons, we sampled twice in 2 habitat types (5 leaf patches in pools and 5 in riffles) in each of 9 stream sites distributed in 3 different river basins. We computed average pairwise beta diversity among sampling stations and seasons in each stream site by using Jaccard and Bray-Curtis indices, and calculated the percentages of diversity resulting from turnover and nestedness. Finally, we tested the degree that local- or catchment-level predictor variables explained beta diversity. We found that turnover was the main component of beta diversity and that both dissolved oxygen and elevation range best explained Bray-Curtis beta diversity. These results reinforce the importance of leaf patches in montane (sky islands) neotropical savanna streams as biodiversity hotbeds for macroinvertebrates, and that both local and landscape variables explained beta diversity.

Does salinization impact long-term Daphnia assemblage dynamics? Evidence from the sediment egg bank in a small hard-water lake

Salinization of freshwater ecosystems threatens global aquatic biodiversity. There is a need for studies that follow populations in situ during salinization to understand the effects on species and ecosystems. We follow 170 years of Daphnia dynamics in the sediment ephippia archive of a small urban lake near St. Paul, Minnesota, to characterize effects of severe recent salinization on lake Daphnia. We found modest changes in the flux of ephippia in this lake; all three key Daphnia functional groups remained in the assemblage throughout the period of salinization. Reconstruction of the size distribution of D. pulicaria demonstrated that predation pressure by fish may not have increased for the largest and most susceptible member of the assemblage despite cultural meromixis. Our findings highlight that in hardwater lakes, the effects of salinization are nuanced and require further investigation to better understand overall impacts of salinization on lake Daphnia assemblages.

Taxonomic and functional compositions and environmental data of 19 seedling assemblages in a Caatinga dry forest

We used these information to assess the structure, composition, and diversity of woody seedling assemblages across 19 forest stands in a human-modified landscape of Caatinga dry forest, assessing the role played by rainfall, aboveground biomass, and chronic anthropogenic disturbances (i.e., livestock grazing pressure and wood extraction) as assembly forces. We quantified a large set of community-level attributes including functional traits related to water availability, physical protection, and survival success. We recorded a total of 544 seedlings from 59 species.

Supporting tables and figures for Cancel Villamil JJ, Locke SA (2022) - Fish assemblage response to removal of a low‐head dam in the lower reach of a tropical island river, Freshwater Biology

Table S1 summarizes studies of the effects of dams on freshwater fish assemblages Table S2 provides results of fishing in 39 samples in three rivers in Puerto Rico in 2017-2019. See 2, below. Figure S1 shows the relationship between fish species richness and time spent electrofishing in these samples. Abstract of article: 1. Dams are often removed from rivers to restore habitat connectivity for biota such as fish. Removal of inland dams is well studied in temperate mainland rivers but this approach has been little studied in fish assemblages in islands, tropic systems, or for dams near the mouth of the river. In Puerto Rico, one of the most intensively dammed territories in the world, all native river fishes migrate between fresh water and the sea, and previous work shows these movements are impeded or blocked by dams. 2. Fish assemblages were compared before and after removal of the Cambalache dam, a porous, low-head structure near the mouth of the Río Grande de Arecibo, as well as in two other rivers in Western Puerto Rico, one with a similarly sized and positioned dam, and one reference river without artificial barriers. Fish were sampled using backpack electrofishing on 39 occasions during 2017-2019, including seven samples collected after removal of the Cambalache dam, at between four and six sites per river. 3. Fish assemblages upstream from dams were poorer in species, and species richness showed a marginal tendency (P=0.0515) to increase upstream of the Cambalache dam three months after its removal. The two small lowland dams studied herein limited the upstream extent of marine species, which recolonized upstream sites of the Río Grande de Arecibo after removal of the Cambalache dam. An estimate of relative density (catch per unit effort) of common native freshwater species was higher above these two dams, and decreased at upstream sites after removal of the Cambalache dam. The estimated relative density of a native freshwater species that is of conservation concern, the American eel (Anguilla rostrata), was reduced above dams, and increased upstream of the former Cambalache dam after its removal. 4. In extensive surveys conducted previously in Puerto Rico, sampling was concentrated higher in the watershed, and native fishes were more common and abundant below than above dams. The present work was conducted near the river mouth, and opposite results were observed. These contrasting results suggest that the effects of dams (or dam removal) on fish assemblages vary along the river gradient, although data from other systems are needed to confirm this. 5. The present results suggest low-head dam removal to be a viable method of restoring connectivity in fish assemblages in lower reaches of rivers in Puerto Rico and, potentially, other tropical islands. Removal of dams near the mouth of the river appears to be of particular benefit to marine fish species that use lower river reaches.

Mechanisms of dietary resource partitioning in large-herbivore assemblages: a plant-trait-based approach

Sympatric large mammalian herbivore species differ in diet composition, both by eating different parts of the same plant and by eating different plant species. Various theories proposed to explain these differences are not mutually exclusive, but are difficult to reconcile and confront with data. Moreover, whereas several of these ideas were originally developed with reference to within-plant partitioning (i.e., consumption of different tissues), they may analogously apply to partitioning of plant species; this possibility has received little attention. Plant functional traits provide a novel window into herbivore diets and a means of testing multiple hypotheses in a unified framework. We used DNA metabarcoding to characterize the diets of 14 sympatric large-herbivore species in an African savanna and analyzed diet composition in light of 27 functional traits that we measured locally for 204 plant species. Plant traits associated with the deep phylogenetic split between grasses and eudicots formed the primary axis of resource partitioning, affirming the generality and importance of the grazer-browser spectrum. A secondary axis comprised plant traits relevant to herbivore body size. Plant taxa in the diets of large-bodied species were lower on average in digestible energy and protein, taller on average (especially among grazers), and tended to be higher in tensile strength, zinc, stem-specific density, and potassium (and lower in sodium, stem dry matter content, and copper). These results are consistent with longstanding hypotheses linking body size with forage quality and plant height, yet they also suggest the existence of undiscovered links between herbivore body size and a set of rarely considered food-plant traits. We also tested the novel hypothesis that the leaf economic spectrum (LES), a major focus in plant ecology, is an axis of resource partitioning in large-herbivore assemblages; we found that the LES was a minor axis of individual variation within a few species, but had little effect on interspecific dietary differentiation. Synthesis. These results identify key plant traits that underpin the partitioning of food-plant species in large-herbivore communities and suggest that accounting for multiple plant traits (and tradeoffs among them) will enable a deeper understanding of herbivore-plant interaction networks.

opencc-zeroFeb 2022View details →

Data from: Joint effects of environmental filtering and dispersal limitation on species assemblage of the Tibetan Plateau

Aim Mountains harbour a rich and non-random cluster of species, yet knowledge on the species' biological attributes that support species coexistence in the montane community is limited. Here, we investigated the association of species occurrence on the Tibetan Plateau with species' morphological, ecological or evolutionary constraints. Location Tibetan Plateau (TP) Taxon Mammals and birds Methods We tested whether species occurrence on the TP correlates with morphological, ecological, or evolutionary constraints using the spatial distribution, phylogeny, dispersal ability, and thermal niche property data for 1,353 terrestrial vertebrates (383 mammals and 970 birds). We used standard (non-phylogenetic) and phylogenetic logistic regressions to disentangle the relative contributions of these attributes of species in explaining the species occurrence on the TP. We assessed the geographical patterns of community structures on the TP and fit linear mixed models to explore the underlying eco-evolutionary forces. Results The TP species exhibited a higher cold tolerance, wider thermal niche breadth, and higher rate of niche evolution than the non-TP species. We supported the assumption that the TP species was not a random subset from the species pool, but was structured jointly by environmental filtering and dispersal limitation. While dispersal and ecological processes underlying species assemblages varied spatially and among taxa, we found that species in stressful environments was limited by environmental filtering, whereas dispersal limitation was more pronounced under favourable climatic conditions. Main conclusions Our study finds that environmental filtering and dispersal limitation jointly shape the species assemblage on the TP. These findings provide significant insights into community assembly processes on the TP and other montane ecosystems on Earth, especially those that are sensitive to global warming.

FIGURE 10. Claviscopulia facunda. A in Manned submersible dives reveal a singular assemblage of Hexactinellida (Porifera) off the Amazon River mouth, Northern Brazil

FIGURE 10. Claviscopulia facunda. A, specimen in situ; B–C, fresh specimens onboard: B, MNRJ 21294; C, MNRJ 21295 (with associated crinoid). Photographs by F. Moraes.

FIGURE 8 in Manned submersible dives reveal a singular assemblage of Hexactinellida (Porifera) off the Amazon River mouth, Northern Brazil

FIGURE 8. Megascleres of Dactylocalyx pumiceus (SEM). A, normal pentactin; B, asymmetrical hexactin with long, sinuous, filamentous rays; C, normal hexactin; D, heptactin. Insets: actin tips.

FIGURE 14 in Manned submersible dives reveal a singular assemblage of Hexactinellida (Porifera) off the Amazon River mouth, Northern Brazil

FIGURE 14. Environment and populations of Hexactinellida off the Amazon River mouth, Northern Brazil. A, Hyalonema (Cyliconemaoida) alucia sp. nov. on muddy sand bottom off Pará State, 378 m depth; B, Claviscopulia facunda population on coarse sand to gravel bottom off Pará State, 250 m depth; C, Dactylocalyx pumiceus on rocky outcrop off Pará State, 260 m depth; D–F, Dense sponge community dominated by Dactylocalyx pumiceus on hard carbonate bottom off Maranhão State, at 170 m depth (D) and 180 m depth (E). Photographs by F. Moraes (A–C) and R. Moura (D–E).

FIGURE 7 in Manned submersible dives reveal a singular assemblage of Hexactinellida (Porifera) off the Amazon River mouth, Northern Brazil

FIGURE 7. Skeleton of Dactylocalyx pumiceus (SEM). A, B, dictyonalia with long, sinuous, filamentous rays of asymmetrical pentactins and hexactins. C, dictyonalia with few pentactins; D, dictyonalia associated with abundant free hexasters; E, fused hexactin; F, club-shaped spined ray of fused hexactin with terminal knob.

FIGURE 3 in Manned submersible dives reveal a singular assemblage of Hexactinellida (Porifera) off the Amazon River mouth, Northern Brazil

FIGURE 3. Skeleton of Hyalonema (Cyliconemaoida) alucia sp. nov. A, choanosomal skeleton with disorganized diactins and less common hexactins; B, dermal skeleton with the pinular rays of pinular pentactins pointing outwards, and tangential diactins (SEM).

FIGURE 6 in Manned submersible dives reveal a singular assemblage of Hexactinellida (Porifera) off the Amazon River mouth, Northern Brazil

FIGURE 6. External morphology of Dactylocalyx pumiceus. A–E, living specimens in situ (A, B off Pará State, C–E off Maranhão State). Arrow in D points to a derelict fishing line threatening the sponge; F, fresh specimen onboard; G, detail of outer surface showing openings of tubules; H, fragment of specimen after fixation with long grooves (A, F, G: MNRJ 21299; C, H: MNRJ 21284; B, D, E: not collected). Photographs by F. Moraes (A–B), and R. Moura (C–E).

FIGURE 2 in Manned submersible dives reveal a singular assemblage of Hexactinellida (Porifera) off the Amazon River mouth, Northern Brazil

FIGURE 2. Hyalonema (Cyliconemaoida) alucia sp. nov., external morphology (holotype). A, specimen in situ; B-D, specimen after fixation: B, whole specimen with associated zoanthids (side view); C, apical cone (side view); D, oscular sieve-plate (top view). In situ photograph by F. Moraes (A).

FIGURE 1. Study area and sampling operation. A in Manned submersible dives reveal a singular assemblage of Hexactinellida (Porifera) off the Amazon River mouth, Northern Brazil

FIGURE 1. Study area and sampling operation. A, map of South America and Brazil depicting the study area (rectangle); B, insert depicting the Amazon River mouth region with the two manned submersible diving stations where hexactinellids were sampled: one dive included sites 1–3, off Pará State and the other included site 4, off Maranhão State. Site 1—Claviscopulia facunda, site 2—Dactylocalyx pumiceus (white morphotype), site 3—Hyalonema (Cyliconemaoida) alucia sp. nov., site 4—aggregation of Dactylocalyx pumiceus (cream morphotype); C, MV Alucia launching the manned submersible Deep Rover; D, sampling of Hyalonema (Cyliconemaoida) alucia sp. nov. using the submersible's mechanical arm. C-D, photographs by F. Moraes.