scholarly journals Musical Chairs on Temperate Reefs: Species Turnover and Replacement Within Functional Groups Explain Regional Diversity Variation in Assemblages Associated With Honeycomb Worms

2021 ◽  
Vol 8 ◽  
Author(s):  
Alexandre Muller ◽  
Camille Poitrimol ◽  
Flávia L. D. Nunes ◽  
Aurélien Boyé ◽  
Amelia Curd ◽  
...  

Reef-building species are recognized as having an important ecological role and as generally enhancing the diversity of benthic organisms in marine habitats. However, although these ecosystem engineers have a facilitating role for some species, they may exclude or compete with others. The honeycomb worm Sabellaria alveolata (Linnaeus, 1767) is an important foundation species, commonly found from northwest Ireland to northern Mauritania, whose reef structures increase the physical complexity of the marine benthos, supporting high levels of biodiversity. Local patterns and regional differences in taxonomic and functional diversity were examined in honeycomb worm reefs from 10 sites along the northeastern Atlantic to explore variation in diversity across biogeographic regions and the potential effects of environmental drivers. While taxonomic composition varied across the study sites, levels of diversity remained relatively constant along the European coast. Assemblages showed high levels of species turnover compared to differences in richness, which varied primarily in response to sea surface temperatures and sediment content, the latter suggesting that local characteristics of the reef had a greater effect on community composition than the density of the engineering species. In contrast, the functional composition of assemblages was similar regardless of taxonomic composition or biogeography, with five functional groups being observed in all sites and only small differences in abundance in these groups being detected. Functional groups represented primarily filter-feeders and deposit-feeders, with the notable absence of herbivores, indicating that the reefs may act as biological filters for some species from the local pool of organisms. Redundancy was observed within functional groups that may indicate that honeycomb worm reefs can offer similar niche properties to its associated assemblages across varying environmental conditions. These results highlight the advantages of comparing taxonomic and functional metrics, which allow identification of a number of ecological processes that structure marine communities.

2021 ◽  
Author(s):  
Haijun Yuan ◽  
Weizhen Zhang ◽  
Huaqun Yin ◽  
Runyu Zhang ◽  
Jianjun Wang

Abstract Microbial beta diversity has been recently studied along the water depth in aquatic ecosystems, however its turnover and nestedness components remain elusive especially for multiple taxonomic groups. Based on the beta diversity partitioning developed by Baselga and Local Contributions to Beta Diversity (LCBD) partitioning by Legendre, we examined the water-depth variations in beta diversity components of bacteria, archaea and fungi in surface sediments of Hulun Lake, a semi-arid lake in northern China, and further explored the relative importance of environmental drivers underlying their patterns. We found that the relative abundances of Proteobacteria, Chloroflexi, Euryarchaeota and Rozellomycota increased towards deep water, while Acidobacteria, Parvarchaeota and Chytridiomycota decreased. For bacteria and archaea, there were significant (P < 0.05) decreasing water-depth patterns for LCBD and LCBDRepl (i.e., species replacement), while increasing patterns for total beta diversity and turnover, implying that total beta diversity and LCBD were dominated by species turnover or LCBDRepl. Further, bacteria showed a strong correlation with archaea regarding LCBD, total beta diversity and turnover. Such parallel patterns among bacteria and archaea were underpinned by similar ecological processes like environmental selection. Total beta diversity and turnover were largely affected by sediment total nitrogen, while LCBD and LCBDRepl were mainly constrained by water NO2−-N and NO3−-N. For fungal community variation, no significant patterns were observed, which may be due to different drivers like water nitrogen or phosphorus. Taken together, our findings provide compelling evidences for disentangling the underlying mechanisms of community variation in multiple aquatic microbial taxonomic groups.


2013 ◽  
Vol 4 (2) ◽  
pp. 138 ◽  
Author(s):  
Patricia Marti-Puig ◽  
Federica Costantini ◽  
Luca Rugiu ◽  
Massimo Ponti ◽  
Marco Abbiati

Temperate reefs are among the most threatened marine habitats due to impacts caused by high density of human settlements, coastal development, pollution, fisheries and tourism. Networks of marine protected areas (MPAs) are an important tool for ensuring long-term health and conservation of ecological processes in the marine environment. Design of the MPA network has to be based on deep understanding of spatial patterns of species distribution, and on the make-up of connectivity among populations. Most benthic invertebrates are sessile and/or sedentary in the adult phase, and their dispersal relies mainly on the gametes and/or larval behaviours. Genetic markers allow us to quantify gene flow and structuring among populations, and to infer patterns of genetic connectivity. Based on the information available in the peer reviewed literature on genetic connectivity in benthic invertebrates of temperate MPAs, we provide a comment about the gaps and the needs. Moreover, we propose a rationale to plan and optimise future studies on this topic. A conceptual framework for planning effective studies on genetic connectivity in an MPAs network is provided, including general recommendations on sampling design, key species and molecular markers to use.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Marina Schmidt Dalzochio ◽  
Eduardo Périco ◽  
Norton Dametto ◽  
Göran Sahlén

Abstract All natural populations show fluctuations in space or time. This is fundamental for the maintenance of biodiversity, as it allows species to coexist. Long-term ecological studies are rare, mainly due to logistics, but studies like the one presented below recognize the dimensionality of temporal change and the ecological processes that lead to shifts in community composition over time. Here, we used three sampling occasions from a dataset spanning 20 years where dragonflies in central Sweden were monitored. Our aim was to investigate how the prevalence of ecological and biological species traits varied over time measured as Community-level Weighted Means of trait values (CWM). Most CWM values varied significantly between years. Most of the traits changed between the second and the last sampling occasion, but not between the two first ones. These changes could be linked to major changes in species abundance. Our work indicates that fundamental shifts in community structure can occur over a short time, providing environmental drivers act on species turnover. In our case, Climate change and pH levels in lakes are most likely the most important factors.


2021 ◽  
Vol 7 (5) ◽  
pp. 333
Author(s):  
Lourdes Morillas ◽  
Javier Roales ◽  
Cristina Cruz ◽  
Silvana Munzi

Lichens are classified into different functional groups depending on their ecological and physiological response to a given environmental stressor. However, knowledge on lichen response to the synergistic effect of multiple environmental factors is extremely scarce, although vital to get a comprehensive understanding of the effects of global change. We exposed six lichen species belonging to different functional groups to the combined effects of two nitrogen (N) doses and direct sunlight involving both high temperatures and ultraviolet (UV) radiation for 58 days. Irrespective of their functional group, all species showed a homogenous response to N with cumulative, detrimental effects and an inability to recover following sunlight, UV exposure. Moreover, solar radiation made a tolerant species more prone to N pollution’s effects. Our results draw attention to the combined effects of global change and other environmental drivers on canopy defoliation and tree death, with consequences for the protection of ecosystems.


2016 ◽  
Vol 75 (s2) ◽  
Author(s):  
Giuseppe Morabito

Lake Orta (Northern Italy) became one of the world’s largest acidic lakes, following industrial pollution, beginning in the late 1920s. Prior to pollution, Lake Orta supported a rich and diversified phytoplankton community dominated by diatoms, cyanobacteria and dinoflagellates. Their taxonomic composition was comparable to that of the nearby Lake Maggiore, which provides a useful reference comparison. After pollution, Lake Orta was so acidic and contaminated with trace metals that only a few tolerant phytoplankton species persisted, supplemented by sudden and short living outbursts of occasional colonists. The lake was limed in 1989-1990. This has permitted the gradual recovery of its chemistry and biology, and many phytoplankton species that inhabit Lake Maggiore are now re-appearing in Lake Orta. I tested the two hypotheses that Lakes Orta and Maggiore would now have a similar phytoplankton taxonomic assemblages, and similar diversity of functional groups given their similar morphometry, physical features and trophic states. The two hypotheses were tested by comparing the phytoplankton assemblages of lakes Maggiore and Orta for the first 10 years after liming, i.e. 1990 to 2001. Phytoplankton was classified according the Reynolds' Morpho Functional Groups and five diversity indices were calculated (<em>S</em>, number of units; <em>H</em>, Shannon-Wiener; <em>E</em>, evenness; <em>D</em>, dominance; <em>J</em>, equitability). SHE analysis (an analysis of diversity changes based on the relationship among species richness (S), H Index (H) and evenness (E)) was also carried out, in order to compare the long term trend of both functional groups and taxa biodiversity. Both taxonomic and the functional composition differed in the two lakes, likely because chemical quality have played a role in <em>taxa</em>selection. Moreover, it was quite clear that, during the first post-liming decade, Lake Orta’s phytoplankton was characterized by low diversity and evenness and by marked year-to-year fluctuations. However, SHE analysis showed that the colonization rate was higher in Lake Orta than in Lake Maggiore, and that the environmental modifications caused by the liming were opening new ecological niches, allowing some colonists to thrive in the changing, albeit still unusual chemical environment of the lake.<p> </p>


2019 ◽  
Vol 54 (3) ◽  
pp. 407-418
Author(s):  
Piotr Perliński ◽  
Zbigniew J. Mudryk ◽  
Marta Zdanowicz

Abstract The abundance of bacteria inhabiting the sediment-water interface and their taxonomic composition were determined with the fluorescence in situ hybridization (FISH) method in a marine harbor channel in Ustka. Among bacteria inhabiting the studied layer Gammaproteobacteria (1.4 cells 108·dm−3) and Cytophaga-Flavobacterium (1.1 cells 108·dm−3) dominated. Vibrio and Pseudomonas represented only a small fraction of the total cell counts. All taxonomic groups of studied bacteria show significant positive correlation between their abundance. The total bacterial number varied from 3.3 to 23.5 cells 108·dm−3 and their biomass oscillated from 39.4 to 282.4 μg C·dm−3. This parameter differed along horizontal profiles, while there were no significant differences in the abundance of the studied taxonomic groups among the study sites of the channel in Ustka. The total number of bacteria as well as the abundance of bacterial phylogenetic groups were subject to seasonal fluctuation in the studied water basin.


2012 ◽  
Vol 69 (10) ◽  
pp. 1642-1650 ◽  
Author(s):  
Paul C. Frost ◽  
Andrea L. Hicks

Human activities associated with residential development potentially alter ecological processes in lake littoral zones. We determined how the nutrient stoichiometry of aquatic plant communities relates to residential density around lakes of south-central Ontario. We calculated the elemental composition of entire plant communities from multiple sites in 12 lakes using measurements of individual plant C:N:P ratios and their areal biomass. We found considerable variability in the C:N:P ratios of whole aquatic plant communities among sites and lakes, which was not accounted for by intraspecific variability in the elemental composition of aquatic plants. Instead, differences in community-level C:N:P ratios primarily resulted from high interspecific variability in the elemental composition among dominant plant taxa and variable taxonomic composition of sampled plant communities. Plant community composition differed among lakes with and without shoreline residences, and we found lower C:N and C:P ratios in communities from littoral zones in human-developed lakes. Our results thus demonstrate a link between the elemental and taxonomic composition of aquatic plant communities, which may mediate biogeochemical responses of littoral zones to development of lake shorelines.


2019 ◽  
Author(s):  
Hideyuki Doi ◽  
Ryutei Inui ◽  
Shunsuke Matsuoka ◽  
Yoshihisa Akamatsu ◽  
Masuji Goto ◽  
...  

AbstractInformation on alpha (local), beta (between habitats), and gamma (regional) diversity is fundamental to understanding biodiversity as well as the function and stability of community dynamics. The methods like environmental DNA (eDNA) metabarcoding are currently considered useful to investigate biodiversity.We compared the performance of eDNA metabarcoding with visual and capture surveys in estimating alpha/gamma diversity and the variation of the community assemblages of river fish communities, particularly considering community nestedness and turnover.In five rivers across west Japan, with comparing to visual/capture surveys, eDNA metabarcoding detected more species in the study sites, consequently the overall number of species in the region (i.e., gamma diversity) was higher. In particular, the species found by visual/capture surveys were encompassed by those by eDNA metabarcoding.With analyzing the community assemblages between the rivers, we showed the different results between the both methods. While, in the same river, the nestedness and species turnover changing from upstream to downstream did not significantly differ between the both methods. Our results suggest that eDNA metabarcoding may be suitable method, especially for understanding regional community patterns, for fish monitoring in rivers.


2019 ◽  
Vol 12 (6) ◽  
pp. 1047-1058 ◽  
Author(s):  
Hélio Menegat ◽  
Divino Vicente Silvério ◽  
Henrique A Mews ◽  
Guarino R Colli ◽  
Ana Clara Abadia ◽  
...  

Abstract Aims Different plant functional groups display diverging responses to the same environmental gradients. Here, we assess the effects of environmental and spatial predictors on species turnover of three functional groups of Brazilian savannas (Cerrado) plants—trees, palms and lianas—across the transition zone between the Cerrado and Amazon biomes in central Brazil. Methods We used edaphic, climatic and plant composition data from nine one-hectare plots to assess the effects of the environment and space on species turnover using a Redundancy Analysis and Generalized Dissimilarity Modeling (GDM), associated with variance partitioning. Important Findings We recorded 167 tree species, 5 palms and 4 liana species. Environmental variation was most important in explaining species turnover, relative to geographic distance, but the best predictors differed between functional groups: geographic distance and silt for lianas; silt for palms; geographic distance, temperature and elevation for trees. Geographic distances alone exerted little influence over species turnover for the three functional groups. The pure environmental variation explained most of the liana and palm turnover, while tree turnover was largely explained by the shared spatial and environmental contribution. The effects of geographic distance upon species turnover leveled off at about 300 km for trees, and 200 km for lianas, whereas they were unimportant for palm species turnover. Our results indicate that environmental factors that determine floristic composition and species turnover differ substantially between plant functional groups in savannas. Therefore, we recommend that studies that aim to investigate the role of environmental conditions in determining plant species turnover should examine plant functional groups separately.


2003 ◽  
Vol 48 (7) ◽  
pp. 65-72 ◽  
Author(s):  
J.F. Costelloe ◽  
J.T. Puckridge ◽  
J.R.W. Reid ◽  
J. Pritchard ◽  
P. Hudson ◽  
...  

The ARIDFLO project takes a multi-disciplinary approach to the collection and analysis of data required to formulate appropriate environmental flow requirements for rivers in the Lake Eyre Basin. The key drivers of the ecological processes underpinning the health of these rivers are identified by modelling whole-of-ecosystem biological responses to hydrological events over a range of spatial and temporal scales. First, the hydrology of these poorly gauged (often ungauged) rivers needs to be modelled and validated to mimic real flow and inundation patterns at the catchment, reach and waterbody scale. Modelled and actual discharge data are then used to provide a suite of hydrological predictor variables which, in conjunction with other environmental variables, are used to model observed biotic responses. The key hydrologic and environmental drivers identified by the statistical models need to be taken into account when determining environmental flow requirements for these river systems. Further work is required to assess the predictive power of the models in the highly variable, complex systems of the Lake Eyre Basin rivers.


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