Nematodes from extreme and unusual freshwater habitats.

2021 ◽  
pp. 109-150
Author(s):  
Mike Hodda ◽  
Walter Traunspurger
Keyword(s):  
Chemical Composition ◽  
Species Interactions ◽  
Estuarine Sediments ◽  
Polar Regions ◽  
Higher Taxa ◽  
Tree Hollows ◽  
Freshwater Habitats ◽  
Ecological Patterns ◽  
Extreme Habitats ◽  
Freshwater Environments

Abstract This chapter discusses the ecology and biogeography of nematodes from freshwater environments that are extreme in temperature, chemical composition, variability, or isolation. Described and compared are the compositions of nematode faunas from hot or mineral springs, pools and bogs in polar regions, intermittent lakes or pools or streams, freshwater pools in bromeliads or tree hollows, stemflow, fresh groundwaters, and caves. Comparisons of the nematode faunas from these extreme habitats with those from more typical freshwater environments are also provided. Also discussed are nematodes with evolutionary affinities to freshwaters that are found in estuarine sediments along with nematodes from freshwaters with evolutionary affinities to otherwise marine taxa. The emphasis is on broad ecological patterns rather than on detailed species interactions with the various freshwater environments. Thus, the chapter focuses on genera or higher taxa rather than species.

Benthic species as mud patrol - modelled effects of bioturbators and biofilms on large-scale estuarine mud and morphology

2021 ◽  
Author(s):  
Muriel Brückner ◽  
Christian Schwarz ◽  
Giovanni Coco ◽  
Anne Baar ◽  
Márcio Boechat Albernaz ◽  
...  
Keyword(s):  
Morphological Change ◽  
Species Interactions ◽  
Large Scale ◽  
Habitat Degradation ◽  
Species Abundance ◽  
Estuarine Sediments ◽  
Morphological Development ◽  
Benthic Species ◽  
Species Dominance ◽  
Species Specific

<p>Benthic species that live within estuarine sediments stabilize or destabilize local mud deposits through their eco-engineering activities, affecting the erosion of intertidal sediments. Possibly, the altered magnitudes in eroded sediment affect the large-scale redistribution of fines and hence morphological change. To quantify this biological control on the morphological development of estuaries, we numerically model i) biofilms, ii) two contrasting bioturbating species present in NW-Europe, and iii) their combinations by means of our novel eco-morphodynamic model. The model predicts local mud erodibility based on species pattern, which dynamically evolves from the hydrodynamics, soil mud content, competition and grazing, and is fed back into the hydromorphodynamic computations.</p><p>We find that biofilms reduce mud erosion on intertidal floodplains and stabilize estuarine morphology, whereas the two bioturbators significantly enhance inter- and supratidal mud erosion and bed elevation change, leading to a large-scale reduction in deposited mud and a widening of the estuary. In turn, the species-dependent changes in mud content redefines their habitat and leads to a redistribution of species abundances. Here, the eco-engineering affects habitat conditions and species abundance while species interactions determine species dominance. Our results show that species-specific biostabilization and bioturbation determine large-scale morphological change through mud redistribution, and at the same time affect species distribution. This suggests that benthic species have subtly changed estuarine morphology through space and time and that aggravating habitat degradation might lead to large effects on the morphology of future estuaries.</p>

scholarly journals Should I stay or should I go? The Ectodysplasin locus is associated with behavioural differences in threespine stickleback

2009 ◽  
Vol 5 (6) ◽  
pp. 788-791 ◽  
Author(s):  
Rowan D. H. Barrett ◽  
Tim H. Vines ◽  
Jason S. Bystriansky ◽  
Patricia M. Schulte
Keyword(s):  
Positive Selection ◽  
Local Adaptation ◽  
Morphological Traits ◽  
Genetic Basis ◽  
Natural Populations ◽  
Threespine Stickleback ◽  
Adaptive Divergence ◽  
Freshwater Habitats ◽  
Repeated Evolution ◽  
Freshwater Environments

Adaptive divergence may be facilitated if morphological and behavioural traits associated with local adaptation share the same genetic basis. It is therefore important to determine whether genes underlying adaptive morphological traits are associated with variation in behaviour in natural populations. Positive selection on low-armour alleles at the Ectodysplasin ( Eda ) locus in threespine stickleback has led to the repeated evolution of reduced armour, following freshwater colonization by fully armoured marine sticklebacks. This adaptive divergence in armour between marine and freshwater populations would be facilitated if the low allele conferred a behavioural preference for freshwater environments. We experimentally tested whether the low allele is associated with preference for freshwater by measuring the preference of each Eda genotype for freshwater versus saltwater after acclimation to either salinity. We found no association between the Eda low allele and preference for freshwater. Instead, the low allele was significantly associated with a reduced preference for the acclimation environment. This behaviour may facilitate the colonization of freshwater habitats from the sea, but could also hinder local adaptation by promoting migration of low alleles between marine and freshwater environments.

Are leaf-litter frogs and lizards affected by edge effects due to forest fragmentation in Brazilian Atlantic forest?

2008 ◽  
Vol 24 (05) ◽  
pp. 551-554 ◽  
Author(s):  
Marianna Dixo ◽  
Marcio Martins
Keyword(s):  
Edge Effects ◽  
Vegetation Structure ◽  
Environmental Changes ◽  
Forest Edge ◽  
Habitat Types ◽  
Abiotic Conditions ◽  
Freshwater Habitats ◽  
Ecological Patterns ◽  
Predominant Factor ◽  
Landscape Level

Edge effects encompass biotic and abiotic changes resulting from the interaction between two different habitat types (Murcia 1995). Edge habitats are ecologically distinct from patch interiors, and understanding how ecological patterns change near edges is important in understanding landscape-level dynamics such as the impacts of fragmentation (Rieset al. 2004). Abiotic conditions at the forest edge, such as increased wind and solar radiation, increased fluctuations in temperature, and decreased humidity, may affect forest-adapted organisms (Harperet al. 2005, Murcia 1995). So, edges may affect lizards and amphibians due to their physiological needs (Lehtinenet al. 2003, Vallan 2000). Anurans are considered sensitive to environmental changes due to their permeable skin, shell-less eggs and use of land as well as freshwater habitats (Vallan 2000). Changes in vegetation structure and microclimate are likely to be the predominant factor affecting amphibian abundances across edges (Jellineket al. 2004, Marsh & Pearman 1997, Schaepfer & Gavin 2001, Urbina-Cardonaet al. 2006).

Symbiosis as an evolutionary innovation in the radiation of Paleocene planktic foraminifera

Paleobiology ◽  
1996 ◽  
Vol 22 (4) ◽  
pp. 461-480 ◽  
Author(s):  
Richard D. Norris
Keyword(s):  
Evolutionary Rates ◽  
Planktic Foraminifera ◽  
Significant Control ◽  
Evolutionary Innovation ◽  
Higher Taxa ◽  
Algal Symbiosis ◽  
Ecological Patterns ◽  
Ecological Association ◽  
Important Means

Symbioses are often regarded as an important means for the creation of evolutionary novelty as well as a trigger for the abrupt appearance of higher taxa. The fossil record of foraminifer-algal symbiosis suggests that the appearance of this ecological association contributed to the radiation of Paleogene planktic foraminifera. Isotopic evidence shows that photosymbiosis evolved in synchrony with a major diversification of trochospiral planktic foraminifera about 3.5 m.y. after the end-Cretaceous extinction. In modern planktic foraminifera, photosymbiotic species tend to have more cosmopolitan distributions than asymbiotic foraminifera and a greater ability to withstand periods of nutrient stress. The simultaneous taxonomic radiation and acquisition of photosymbiosis are evidence that the ecological strategy permitted Paleocene foraminifera to expand their niche in pelagic environments by diversifying into low-nutrient surface waters.A comparison of the species longevities of Neogene and Paleogene symbiotic clades suggests that photosymbiosis does not regulate the characteristic rate of taxonomic turnover in clades after they appear. Species longevities are much shorter in Paleocene and Eocene photosymbiotic morphospecies than they are among photosymbiotic Neogene clades; apparently photosymbiosis does not exert a significant control over long-term evolutionary rates. In addition, the absence of a characteristic morphology associated with photosymbiosis in Cenozoic planktic foraminifera suggests that morphology, as with rate of evolutionary turnover, is linked to symbiosis only because of common inheritance instead of a functional relationship. Although the coincidence between the acquisition of photosymbiosis and generic diversification does suggest a linkage between this ecology and the appearance of foraminiferal higher taxa, there is little indication at the present that symbioses control long-term morphological or ecological patterns within these groups after their appearance. Photosymbiosis, and other evolutionary innovations, may be more a catalyst for the differentiation of major groups than a predictable governor on evolutionary rates.

scholarly journals New perspectives on habitat selection by the Black-faced Spoonbill Platalea minor based upon satellite telemetry

2013 ◽  
Vol 23 (4) ◽  
pp. 495-501 ◽  
Author(s):  
CHRIS WOOD ◽  
HIROSHI TOMIDA ◽  
KIM JIN-HAN ◽  
KI-SUP LEE ◽  
HYONG - JU CHO ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Yangtze River ◽  
Satellite Telemetry ◽  
The Other ◽  
The Yangtze River ◽  
Telemetry Data ◽  
Freshwater Habitats ◽  
Visual Confirmation ◽  
The Individual ◽  
Freshwater Environments

SummaryIn 2011 the Black-faced Spoonbill Platalea minor census recorded a 22% drop in numbers from 2010, particularly at the known large coastal wintering sites. During this period, we discovered two new inland wintering sites for the species using satellite telemetry data, one located in China, where the individual followed the Yangtze river as far as Wuhan (500 km inland), and the other across the Vietnam-Cambodia border (70–200 km inland). Long periods of concentrated use of various freshwater habitats were in evidence for these two tagged individuals (China: 79 days, Vietnam/Cambodia: 91 Days) and in the latter case visual confirmation indicated a larger group of at least five individuals. The importance and potential of inland freshwater environments is highlighted towards the further conservation of the recovering population.

scholarly journals Predator macroevolution drives trophic cascades and ecosystem functioning

2018 ◽  
Vol 285 (1883) ◽  
pp. 20180384 ◽  
Author(s):  
Denon Start
Keyword(s):  
Ecosystem Functioning ◽  
Species Interactions ◽  
Scale Up ◽  
Trophic Cascades ◽  
Ecological Impacts ◽  
Phenotypic Traits ◽  
Fish Ponds ◽  
Phenotypic Differences ◽  
Interacting Species ◽  
Ecological Patterns

Biologists now recognize that ecology can drive evolution, and that evolution in turn produces ecological patterns. I extend this thinking to include longer time scales, suggesting that macroevolutionary transitions can create phenotypic differences among species, which then have predictable impacts on species interactions, community assembly and ecosystem functioning. Repeated speciation can exacerbate these patterns by creating communities with similar phenotypes and hence ecological impacts. Here, I use several experiments to test these ideas in dragonfly larvae that occupy ponds with fish, ponds without fish, or both. I show that macroevolutionary transitions between habitats cause fishless pond species to be more active relative to fish pond specialists, reducing prey abundance, shifting prey community composition and creating stronger trophic cascades. These effects scale up to the community level with predictable consequences for ecosystem multi-functioning. I suggest that macroevolutionary history can have predictable impacts on phenotypic traits, with consequences for interacting species and ecosystems.

Biogeography of the Oceans

2020 ◽  
pp. 121-154
Author(s):  
Claudia Halsband ◽  
Shane T. Ahyong ◽  
Angelika Brandt ◽  
Ksenia Kosobokova ◽  
Peter Ward ◽  
...  
Keyword(s):  
Species Interactions ◽  
Life Cycles ◽  
Polar Regions ◽  
Diagnostic Features ◽  
Biogeographic Patterns ◽  
Species Complexes ◽  
Pelagic Larvae ◽  
The Indian Ocean ◽  
High Species Richness ◽  
Hydrographic Features

This chapter summarizes global patterns and mechanisms of both ecological and historical crustacean biogeography resulting in the contemporary species distributions described over the past decades. In the pelagic realm, hydrographic features such as ocean currents, physical depth profiles, and latitudinal temperature gradients are major structuring elements, as well as selection pressure exerted by the environment and species interactions, which have resulted in speciation over evolutionary time. Benthic crustacean distributions are additionally constrained longitudinally by continental barriers and submarine features such as ridges and seamounts. The main biogeographic patterns of both benthic and pelagic crustaceans are described for all ocean basins and the polar regions, of which the Indian Ocean is the least well studied. The Copepoda and Decapoda are generally represented with the highest number of described species, followed by Amphipoda and Isopoda. Life cycles with pelagic larvae (e.g., decapods and stomatopods) increase dispersal and enable wide distributions, while a lack of dispersive larvae promotes endemism in benthic forms (e.g., amphipods). Restricted regions with high species richness and endemism, such as the “coral triangle” (the Indo-Australian Archipelago), the Red Sea, and the Mediterranean, represent important biodiversity hotspots. Endemics are also suitable markers for past earth history events. Only a few studies cover the biogeography of crustacean taxa in all of the world’s oceans, but a few exceptions exist for decapods, amphipods, and isopods. Although the world’s oceans have been reasonably well studied for crustacean distribution and diversity, species complexes and cryptic species lacking morphological diagnostic features leave us with a large number of unconsolidated taxa. Emerging molecular tools may be able to assist with refinement of nomenclature and hence increase the resolution of crustacean biogeography in the future.

scholarly journals New Coelomycetous Fungi from Freshwater in Spain

2021 ◽  
Vol 7 (5) ◽  
pp. 368
Author(s):  
Viridiana Magaña-Dueñas ◽  
Alberto Miguel Stchigel ◽  
José Francisco Cano-Lira
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Pure Culture ◽  
Internal Transcribed Spacer ◽  
Novel Species ◽  
Phylogenetic Study ◽  
Plant Debris ◽  
Internal Transcribed Spacer Region ◽  
Freshwater Habitats ◽  
Freshwater Environments

Coelomycetous fungi are ubiquitous in soil, sewage, and sea- and freshwater environments. However, freshwater coelomycetous fungi have been very rarely reported in the literature. Knowledge of coelomycetous fungi in freshwater habitats in Spain is poor. The incubation of plant debris, from freshwater in various places in Spain into wet chambers, allowed us to detect and isolate in pure culture several pycnidia-producing fungi. Fungal strains were phenotypically characterized, and a phylogenetic study was carried out based on the analysis of concatenated nucleotide sequences of the D1–D2 domains of the 28S nrRNA gene (LSU), the internal transcribed spacer region (ITS) of the nrDNA, and fragments of the RNA polymerase II subunit 2 (rpb2) and beta tubulin (tub2) genes. As a result of these, we report the finding of two novel species of Neocucurbitaria, three of Neopyrenochaeta, and one of Pyrenochaetopsis. Based on the phylogenetic study, we also transferred Neocucurbitaria prunicola to the genus Allocucurbitaria. This work makes an important contribution to the knowledge of the mycobiota of plant debris in freshwater habitats.

Shared Insights across the Ecology of Coral Reefs and African Savannas: Are Parrotfish Wet Wildebeest?

BioScience ◽  
2020 ◽  
Vol 70 (8) ◽  
pp. 647-658
Author(s):  
Deron E Burkepile ◽  
Melissa H Schmitt ◽  
Keenan Stears ◽  
Mary K Donovan ◽  
Dave I Thompson
Keyword(s):  
Natural History ◽  
Coral Reefs ◽  
Species Interactions ◽  
Early Career ◽  
Quantitative Synthesis ◽  
Ecological Patterns ◽  
Primary Focus ◽  
Meta Analyses ◽  
Comparative Systems ◽  
Ecosystem State

Abstract Comparison across terrestrial and aquatic ecosystems facilitates a broader understanding of ecological patterns. Although meta-analyses are important for quantitative synthesis across ecosystems, detailed comparisons of natural history and species interactions also illuminate convergence among systems. We compare the ecology of superficially dissimilar African savannas and coral reefs via shared characteristics including: (1) hyperdiverse guilds of large vertebrate herbivores and predators, (2) similar mechanisms driving positive feedback loops between herbivory and primary production, (3) similar roles of disturbance and herbivory in mediating ecosystem state, and (4) numerous smaller vertebrate and invertebrate species that underpin diversity and ecosystem processes. Our goal in comparing the natural history and ecology of these ecosystems is to facilitate others in finding their own comparative systems. We encourage scientists, especially early-career scientists, to explore ecosystems other than their primary focus. Whatever your ecosystem of study, examining the ecology of its analog in another environment may enliven your career.

Three new Fragilaria species (Bacillariophyta) from low-conductivity mountain freshwaters (Alps and Apennines)

Phytotaxa ◽  
2019 ◽  
Vol 404 (6) ◽  
pp. 261 ◽  
Author(s):  
MARCO CANTONATI ◽  
NICOLA ANGELI ◽  
HORST LANGE-BERTALOT
Keyword(s):  
Climate Change ◽  
Human Disturbance ◽  
Early Warning Systems ◽  
Red List ◽  
Warning Systems ◽  
Early 19Th Century ◽  
Breadth Ratio ◽  
Freshwater Habitats ◽  
Freshwater Environments ◽  
Medium Conductivity

More or less needle-shaped species of Fragilaria s.s. are difficult to identify. Here we contribute to the taxonomy of this difficult group by describing three species new to science from very low conductivity mountain freshwater environments. Two of the new species resemble taxa established by Kützing in the early 19th century: F. rumpens and F. vaucheriae. Fragilaria spinaspeciosa sp. nov., from a seepage (helocrenic spring) in the northern Apennines, is superficially similar to F. rumpens, but has a lower stria density. Fragilaria tridentina sp. nov. is distinguished from F. gracilis by its smaller length-to-breadth ratio and more closely spaced areolae. Fragilaria vaucheriaeraetica sp. nov. is distinguished from F. vaucheriae and F. microvaucheriae by its outline and denser striae. These last three species also have distinctly different ecologies. Fragilaria vaucheriaeraetica sp. nov. is found in very low conductivity, very low nitrate, ultra-oligotrophic waters, while F. vaucheriae and F. microvaucheriae are found in medium conductivity, high total phosphorus, and relatively high nitrate streams. Accurate species identification and knowledge of each species’ ecological preferences are critically important if diatoms are to be used effectively as indicators of environmental impact and climate change. Weakly buffered, low alkalinity, low nutrient and low conductivity mountain freshwater habitats are sensitive to human disturbance and biotopes for many rare (Red List) diatoms. As such, they serve as valuable early warning systems for detecting the effects of climate change and other human activities.

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