scholarly journals Occurrence patterns of coral-dwelling gall crabs (Cryptochiridae) over depth intervals in the Caribbean

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1794 ◽  
Author(s):  
Kaj M. van Tienderen ◽  
Sancia E.T. van der Meij
Keyword(s):  
Depth Distribution ◽  
Environmental Gradients ◽  
Host Coral ◽  
Generalist Species ◽  
Factors Affecting ◽  
Stony Corals ◽  
Reef Degradation ◽  
Associated Species ◽  
Occurrence Patterns ◽  
Gall Crabs

Coral-associated invertebrates form a major part of the diversity on reefs, but their distribution and occurrence patterns are virtually unstudied. For associated taxa data are lacking on their distribution across shelves and environmental gradients, but also over various depths. Off Curaçao we studied the prevalence and density of coral-dwelling gall crabs (Cryptochiridae), obligate symbionts of stony corals. Belt transects (10 × 0.5m2) were laid out at 6, 12 and 18 m depth intervals at 27 localities. Twenty-one known host coral species were surveyed, measured, and the number of crab dwellings was recorded to study the influence of host occurrence, depth distribution, and colony size on the occurrence rates of three Atlantic gall crab species:Opecarcinus hypostegus,Troglocarcinus corallicolaandKroppcarcinus siderastreicola. The overall gall crab prevalence rate was 20.3% across all available host corals at all depths. The agariciid-associated speciesO. hyposteguswas found to mostly inhabitAgaricia lamarckiand its prevalence was highest at deeper depths, following the depth distribution of its host.Kroppcarcinus siderastreicola,associated withSiderastreaandStephanocoenia,inhabited shallower depths despite higher host availability at deeper depths. The generalist speciesT. corallicolashowed no clear host or depth specialisation. These results show that the primary factors affecting the distribution and occurrence rates over depth intervals differed between each of the three Atlantic cryptochirid species, which in turn influences their vulnerability to reef degradation.

Importance of philopatry and hydrodynamics in the recruitment of bioeroding sponges on Indonesian coral reefs

2019 ◽  
Vol 70 (6) ◽  
pp. 755
Author(s):  
Joseph Marlow ◽  
Abdul Haris ◽  
James Bell
Keyword(s):  
Coral Reefs ◽  
Large Scale ◽  
Species Assemblage ◽  
Coral Mortality ◽  
Factors Affecting ◽  
Larval Recruitment ◽  
Spatial Coverage ◽  
Reef Degradation ◽  
Adult Abundance ◽  
Cliona Orientalis

Increasingly frequent large-scale coral mortality events are occurring across the globe, leading to a rise in available reef substrata and promoting an increase in the abundance of other benthic taxa. One such group are bioeroding sponges, which can benefit considerably from reef degradation. However, the occupation of new substrates is partially reliant upon larval recruitment, and currently little is known about the factors affecting bioeroding sponge recruitment. In this study we investigated the potential drivers of bioeroding sponge recruitment using a 2-year deployment of experimental calcareous substrates across seven reefs in the Wakatobi region of Indonesia. Recruitment was observed for five bioeroding sponge species, namely Cliona orientalis, Cliothosa cf. aurivillii, Cliothosa hancocki and two presently unidentified brown clionaids, Cliona aff. viridis sp. A and Cliona aff. viridis sp. B. Recruits were present on 69% of the experimental substrates but had a low mean (±s.e.m.) spatial coverage of just 0.42±0.13%. Total recruitment and species assemblage structure were correlated with local adult abundance, water flow and substrate cues. Our results suggest that any proliferation of bioeroding sponges on newly available substrate following coral mortality is likely to be conditional on local adult abundance and hydrodynamics.

scholarly journals Southern California margin benthic foraminiferal assemblages across a modern environmental gradient record recent centennial-scale changes in oxygen minimum zone

2019 ◽  
Author(s):  
Hannah M. Palmer ◽  
Tessa M. Hill ◽  
Peter D. Roopnarine ◽  
Sarah E. Myhre ◽  
Katherine R. Reyes ◽  
...  
Keyword(s):  
Water Depth ◽  
San Diego ◽  
Environmental Gradient ◽  
Environmental Gradients ◽  
Oxygen Minimum Zone ◽  
Shannon Index ◽  
Spatial Trends ◽  
Minimum Zone ◽  
Associated Species ◽  
Oxygen Minimum

Abstract. Microfossil assemblages provide valuable records to investigate variability in continental margin biogeochemical cycles, including dynamics of the oxygen minimum zone (OMZ). Analyses of modern assemblages across environmental gradients are necessary to understand relationships between assemblage characteristics and environmental factors. Here, we analyzed five cores from the San Diego Margin (32°42'00'' N, 117°30'00'' W, 300–1175 m water depth) for core top benthic foraminiferal assemblages to understand relationships between community assemblages and spatial hydrographic gradients and down core to identify changes in the oxygen minimum zone through time. Comparisons of benthic foraminiferal assemblages from two size fractions (63–150 and > 150 μm) exhibit similar trends across the spatial/environmental gradient, or in some cases exhibit more pronounced spatial trends in the > 150 μm fraction. We identify two hypoxic associated species (B. spissa and U. peregrina), one oxic associated species (G. subglobosa) and one OMZ edge-associated species (B. argentea). A range of species diversity exists within the modern OMZ (1.5–2.6 H, Shannon Index), suggesting that diversity is not driven by oxygenation alone. Down core analysis of indicator species reveal variability in upper margin of the OMZ (528 m water depth) while the core of the OMZ (800 m) and below the OMZ (1175 m) remained stable in the last 1.5 ka. We document expansion of the upper margin of the OMZ beginning 400 ybp on the San Diego Margin that is synchronous with other regional records of oxygenation.

scholarly journals The Within-Population Formation of the Upper Range Limit in a Songbird

2021 ◽  
Author(s):  
Martin Grüebler ◽  
Johann von Hirschheydt ◽  
Fränzi Korner-Nievergelt
Keyword(s):  
Environmental Gradients ◽  
Elevational Gradient ◽  
High Elevation ◽  
Range Limit ◽  
Apparent Survival ◽  
Breeding Sites ◽  
Factors Affecting ◽  
Mobile Species ◽  
Random Dispersal ◽  
High Elevations

Abstract The formation of the upper distributional range limit of species at mountain slopes is often based on environmental gradients resulting in changing demographic rates towards high elevations. However, we still lack an empiric understanding of how the interplay of demographic parameters forms the upper range limit in highly mobile species. Here, we study apparent survival and within-study area dispersal over a 700 m elevational gradient in barn swallows (Hirundo rustica) by using 15 years of capture-mark-recapture data. Annual apparent survival of adult breeding birds decreased while breeding dispersal probability of adult females, but not males increased towards the upper range limit. Individuals at high elevations dispersed to farms situated at lower elevations than would be expected by random dispersal. These results suggest higher turn-over rates of breeding individuals at high elevations, an elevational increase in immigration and thus, within-population source-sink dynamics between low and high elevations. The formation of the upper range limit therefore is based on preference for low-elevation breeding sites and immigration to high elevations. Thus, shifts of the upper range limit are not only affected by changes in the quality of high-elevation habitats but also by factors affecting the number of immigrants produced at low elevations.

scholarly journals Elevation-related climate trends dominate fungal co-occurrence patterns on Mt. Norikura, Japan

2021 ◽  
Author(s):  
Ying Yang ◽  
Yu Shi ◽  
Dorsaf Kerfahi ◽  
Matthew C Ogwu ◽  
Jianjun Wang ◽  
...  
Keyword(s):  
Network Structure ◽  
Fungal Community ◽  
Environmental Gradients ◽  
Elevation Gradient ◽  
Network Connectivity ◽  
Community Diversity ◽  
Dominant Factor ◽  
Mean Annual Precipitation ◽  
Elevation Gradients ◽  
Occurrence Patterns

AbstractAlthough many studies have explored patterns of fungal community diversity and composition along various environmental gradients, the trends of co-occurrence networks across similar gradients remain elusive. Here, we constructed co-occurrence networks for fungal community along a 2300 m elevation gradient on Mt Norikura, Japan, hypothesizing a progressive decline in network connectivity with elevation due to reduced niche differentiation caused by declining temperature and ecosystem productivity. Results agreed broadly with predictions, with an overall decline in network connectivity with elevation for all fungi and the high abundance phyla. However, trends were not uniform with elevation, most decline in connectivity occurred between 700 m and 1500 m elevation, remaining relatively stable above this. Temperature and precipitation dominated variation in network properties, with lower mean annual temperature (MAT) and higher mean annual precipitation (MAP) at higher elevations giving less network connectivity, largely through indirect effects on soil properties. Among keystone taxa that played crucial roles in network structure, the variation in abundance along the elevation gradient was also controlled by climate and also pH. Our findings point to a major role of climate gradients in mid-latitude mountain areas in controlling network connectivity. Given the importance of the orographic precipitation effect, microbial community trends seen along elevation gradients might not be mirrored by those seen along latitudinal temperature gradients.ImportanceAlthough many studies have explored patterns of fungal community diversity and composition along various environmental gradients, it is unclear how the topological structure of co-occurrence networks shifts across environmental gradients. In this study, we found that the connectivity of the fungal community decreased with increasing elevation, and that climate was the dominant factor regulating co-occurrence patterns, apparently acting indirectly through soil characteristics. Assemblages of keystone taxa playing crucial roles in network structure varied along the elevation gradient and were also largely controlled by climate. Our results provide insight into the shift of soil fungal community co-occurrence structure along elevational gradients, and possible driving mechanisms behind this.Graphic abstract

Co-occurrence patterns of rodents at multiple spatial scales: competitive release of generalists following habitat loss?

2019 ◽  
Vol 100 (4) ◽  
pp. 1229-1242 ◽  
Author(s):  
Thomas Püttker ◽  
Camila S Barros ◽  
Bruno T Pinotti ◽  
Adriana A Bueno ◽  
Renata Pardini
Keyword(s):  
Habitat Loss ◽  
Spatial Scales ◽  
Niche Partitioning ◽  
Large Data ◽  
Data Set ◽  
Generalist Species ◽  
Competitive Release ◽  
Spatial Niche ◽  
Habitat Generalist ◽  
Occurrence Patterns

AbstractTheory predicts that habitat generalist species are excluded by specialist species in optimal habitat for specialists, and empirical data commonly show a shift from specialist- to generalist-dominated communities following disturbance. We investigated co-occurrence patterns of habitat generalist and specialist terrestrial rodents at two spatial scales in the Atlantic Forest, aiming at evaluating the following hypotheses: 1) within-patch spatial niche partitioning promotes coexistence of generalists and specialists, leading to checkerboard presence-absence patterns at small (within-patch) rather than large (among-patch) scales; and 2) the decrease in abundance of specialists due to habitat loss promotes a competitive release of generalists, leading to negative covariance in abundance between generalists and specialists among patches. Drawing on a large data set including 363 sites within three patches in continuous forest, and 45 patches within three landscapes, we used C-scores based on presence-absence and abundance data to evaluate spatial segregation. We found consistent segregation between specialists and generalists at the within-patch rather than among-patch scale, but no consistent negative covariance in abundance between generalists and specialists among patches (as covarying species pairs varied across landscapes). Our findings suggest that spatial patterns caused by competition are scale-dependent, and coexistence of generalists and specialists is promoted by within-patch spatial niche partitioning. However, the influence of competitive release on the proliferation of generalists may be outweighed by other factors in fragmented landscapes.A teoria ecológica prevê que espécies generalistas de habitat são excluídas por espécies especialistas em hábitats ótimos para as especialistas, e dados empíricos comumente mostram uma mudança de dominância das comunidades - de especialistas para generalistas - após distúrbios. Nós investigamos os padrões de coocorrência de roedores terrestres generalistas e especialistas de habitat em duas escalas espaciais na Mata Atlântica, para testar as seguintes hipóteses: 1) a partição espacial do nicho dento de fragmentos promove a coexistência de generalistas e especialistas, levando a padrões de presença-ausência “tabuleiro de damas” em escalas pequenas (dentro de fragmento) mas não em escalas grandes (entre fragmentos); 2) a diminuição da abundância de especialistas devido à perda de habitat promove uma liberação competitiva de generalistas, levando a covariância negativa da abundância de generalistas e especialistas entre fragmentos. A partir de um grande banco de dados - 363 sítios dentro de três fragmentos de floresta contínua, e 45 fragmentos dentro de três paisagens, usamos C-scores baseados em dados de presença/ausência e abundância para avaliar a segregação espacial. Encontramos segregação consistente entre especialistas e generalistas na escala menor (dentro de fragmentos) e não na maior (entre fragmentos), mas não encontramos covariância negativa na abundância de generalistas e especialistas entre fragmentos (dado que os pares de espécies que covariaram mudou entre as paisagens). Nossos resultados sugerem que padrões espaciais causados por competição são dependentes de escala, e que a coexistência de generalistas e especialistas é promovida pela partição espacial de nicho dentro dos fragmentos. No entanto, a influência da liberação competitiva na proliferação de generalistas pode ser superada por outros fatores em paisagens fragmentadas.

scholarly journals Host relations and DNA reveal a cryptic gall crab species (Crustacea: Decapoda: Cryptochiridae) associated with mushroom corals (Scleractinia: Fungiidae)

2015 ◽  
Vol 84 (1) ◽  
pp. 39-57b ◽  
Author(s):  
Sancia E.T. van der Meij
Keyword(s):  
Width Ratio ◽  
Crab Species ◽  
Associated Fauna ◽  
Host Coral ◽  
The Third ◽  
Length Width ◽  
Mushroom Coral ◽  
Specificity Pattern ◽  
Gall Crabs ◽  
Host Relations

Mushroom corals of the Indo-West Pacific Fungiidae (Scleractinia) provide habitats for a rich associated fauna, including three species of gall crabs (Cryptochiridae). During the course of the present study gall crabs were sampled from many different fungiid hosts. Based on this ‘reversed’ approach - by studying coral symbionts from a host perspective - a previously unnoticed host specificity pattern was detected. The sampling of gall crab fauna per host coral combined with molecular analyses of H3 nDNA, 16S and COI mtDNA revealed a cryptic gall crab species closely related to Fungicola fagei. This new species, described hereafter as Fungicola syzygia sp. nov., is predominantly associated with the mushroom coral genera Cycloseris and Pleuractis, whereas its sibling species F. fagei is only known to be associated with the host genera Podabacia and Sandalolitha. Based on morphology F. syzygia sp. nov. is difficult to distinguish from F. fagei, but there are subtle differences in carapace shape, the lateral carapace margins, the border between the orbital angles and the merus of the third maxilliped, as well as in the carapace length/width ratio. The type material of F. utinomi and F. fagei is figured for comparison.

scholarly journals Diversification and distribution of gall crabs (Brachyura: Cryptochiridae: Opecarcinus) associated with Agariciidae corals

Coral Reefs ◽  
2021 ◽  
Author(s):  
Tao Xu ◽  
Henrique Bravo ◽  
Gustav Paulay ◽  
Sancia E. T. van der Meij
Keyword(s):  
Nuclear Dna ◽  
Recent Common Ancestor ◽  
Host Coral ◽  
Western Atlantic ◽  
Ancestral Area ◽  
West Pacific ◽  
Symbiotic Associations ◽  
Most Recent Common Ancestor ◽  
Species Complexes ◽  
Gall Crabs

AbstractCoral reefs are home to the greatest diversity of marine life, and many species on reefs live in symbiotic associations. Studying the historical biogeography of symbiotic species is key to unravelling (potential) coevolutionary processes and explaining species richness patterns. Coral-dwelling gall crabs (Cryptochiridae) live in obligate symbiosis with a scleractinian host, and are ideally suited to study the evolutionary history between heterogeneous taxa involved in a symbiotic relationship. The genus Opecarcinus Kropp and Manning, 1987, like its host coral family Agariciidae, occurs in both Indo-Pacific and Caribbean seas, and is the only cryptochirid genus with a circumtropical distribution. Here, we use mitochondrial and nuclear DNA gene fragments of Opecarcinus specimens sampled from 21 Indo-Pacific localities and one Atlantic (Caribbean) locality. We applied several species delimitation tests to characterise species diversity, inferred a Bayesian molecular-clock time-calibrated phylogeny to estimate divergence times and performed an ancestral area reconstruction. Time to the most recent common ancestor (tMRCA) of Opecarcinus is estimated at 15−6 Mya (middle Miocene—late Miocene). The genus harbours ~ 15 undescribed species as well as several potential species complexes. There are indications of strict host-specificity patterns in certain Opecarcinus species in the Indo-Pacific and Atlantic, however, a robust phylogeny reconstruction of Agariciidae corals—needed to test this further—is currently lacking. The Indo-West Pacific was inferred to be the most probable ancestral area, from where the Opecarcinus lineage colonised the Western Atlantic and subsequently speciated into O. hypostegus. Opecarcinus likely invaded from the Indo-West Pacific across the East Pacific Barrier to the Atlantic, before the full closure of the Isthmus of Panama. The subsequent speciation of O. hypostegus, is possibly associated with newly available niches in the Caribbean, in combination with genetic isolation following the closure of the Panama Isthmus.

scholarly journals Southern California margin benthic foraminiferal assemblages record recent centennial-scale changes in oxygen minimum zone

2020 ◽  
Vol 17 (11) ◽  
pp. 2923-2937
Author(s):  
Hannah M. Palmer ◽  
Tessa M. Hill ◽  
Peter D. Roopnarine ◽  
Sarah E. Myhre ◽  
Katherine R. Reyes ◽  
...  
Keyword(s):  
Water Depth ◽  
San Diego ◽  
Environmental Gradient ◽  
Environmental Gradients ◽  
Oxygen Minimum Zone ◽  
Shannon Index ◽  
Spatial Trends ◽  
Minimum Zone ◽  
Associated Species ◽  
Oxygen Minimum

Abstract. Microfossil assemblages provide valuable records to investigate variability in continental margin biogeochemical cycles, including dynamics of the oxygen minimum zone (OMZ). Analyses of modern assemblages across environmental gradients are necessary to understand relationships between assemblage characteristics and environmental factors. Five cores were analyzed from the San Diego margin (32∘42′00′′ N, 117∘30′00′′ W; 300–1175 m water depth) for core top benthic foraminiferal assemblages to understand relationships between community assemblages and spatial hydrographic gradients as well as for down-core benthic foraminiferal assemblages to identify changes in the OMZ through time. Comparisons of benthic foraminiferal assemblages from two size fractions (63–150 and >150 µm) exhibit similar trends across the spatial and environmental gradient or in some cases exhibit more pronounced spatial trends in the >150 µm fraction. A range of species diversity exists within the modern OMZ (1.910–2.586 H, Shannon index), suggesting that diversity is not driven by oxygenation alone. We identify two hypoxic-associated species (B. spissa and U. peregrina), one oxic-associated species (G. subglobosa) and one OMZ edge-associated species (B. argentea). Down-core analysis of indicator species reveals variability in the upper margin of the OMZ (528 m water depth) while the core of the OMZ (800 m) and below the OMZ (1175 m) remained stable in the last 1.5 kyr. We document expansion of the upper margin of the OMZ beginning 400 BP on the San Diego margin that is synchronous with other regional records of oxygenation.

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