scholarly journals Multi-scale functional and taxonomic β-diversity of the macroinvertebrate communities in a Mediterranean coastal lagoon

2017 ◽  
Vol 18 (1) ◽  
pp. 121 ◽  
Author(s):  
D. CABANA ◽  
A. NICOLAIDOU ◽  
K. SIGALA ◽  
S. REIZOPOULOU
Keyword(s):  
Environmental Variability ◽  
Habitat Type ◽  
Time Frame ◽  
Macroinvertebrate Community ◽  
Multiscale Approach ◽  
Significant Heterogeneity ◽  
Macroinvertebrate Communities ◽  
Ecological Processes ◽  
Management Actions ◽  
Β Diversity

Benthic macroinvertebrate communities form the basis of the intricate lagoonal food web. Understanding their functional and taxonomic response, from a β-diversity perspective, is essential to disclose underlying patterns with potential applicability in conservation and management actions. Within the central lagoon of Messolonghi we studied the main environmental components structuring the macroinvertebrate community. We analyzed the β-taxonomic and β-functional diversity across the main habitats and seasons, over a year time frame. Our results outline habitat type and vegetation biomass as the major factors structuring the communities. We found environmental variability to have a positive correlation with functional β-diversity, however no correlation was found with taxonomic β-diversity. Across the seasons an asynchronous response of the functional and taxonomic β-diversity was identified. The taxonomic composition displayed significant heterogeneity during the driest period and the functional during the rainy season. Across the habitats the unvegetated presented higher taxonomic homogeneity and functionally heterogeneity, contrary the vegetated habitats present higher taxonomic variability and functional homogeneity. Across the seasons and habitats a pattern of functional redundancy and taxonomic replacement was identified. Besides high functional turnover versus low taxonomic turnover was documented in an anthropogenic organically enriched habitat We conclude that habitats display independent functional and taxonomic seasonal patterns, thus different processes may contribute to their variability. The framework presented here highlights the importance of studying both β-diversity components framed in a multiscale approach to better understand ecological processes and variability patterns. These results are important to understand macroinvertebrate community assembly processes and are valuable for conservation purposes.

Is the hyporheic zone a refuge for macroinvertebrates in drying perennial streams?

2011 ◽  
Vol 62 (12) ◽  
pp. 1373 ◽  
Author(s):  
B. A. Young ◽  
R. H. Norris ◽  
F. Sheldon
Keyword(s):  
Hyporheic Zone ◽  
Macroinvertebrate Community ◽  
Low Flow ◽  
Macroinvertebrate Communities ◽  
Human Disturbances ◽  
Taxa Richness ◽  
Stream Communities ◽  
Β Diversity ◽  
Dry Conditions ◽  
Streambed Drying

Drought and drying of perennial streams plays a central role in determining the structure of in-stream communities, decreasing taxa richness and abundance and changing trophic organisation. Further, flow cessation can increase spatial β-diversity of macroinvertebrate communities across disconnected sites. It has been hypothesised that the hyporheic zone may act as a refugium for benthic macroinvertebrates during low flow and flow cessation, but evidence remains equivocal. We explored hyporheic and surface benthic macroinvertebrate community changes associated with low flow and flow cessation conditions during a supra-seasonal drought on two normally perennial rivers: the Cotter and Queanbeyan Rivers (Canberra, ACT). Surface benthic and hyporheic samples were collected from these two rivers and four associated tributary streams across a drying gradient during dry conditions and after flow recovery to test whether macroinvertebrates in perennial streams utilise the hyporheic zone as a refugium and whether there is greater variability in the macroinvertebrate community at sites experiencing flow cessation compared with wetter sites. Low flow had no impact on macroinvertebrate taxa richness or density in either surface benthic or hyporheic habitats, whereas density and taxa richness declined during streambed drying, suggesting that the hyporheic zone did not provide a refugium for some taxa during these dry conditions. Spatial β-diversity peaked at dry sites, likely in response to the broad range of environmental conditions that may differ between refuges and sites, but decreased after flow recovery. Refuges in perennial streams appear more vulnerable to human disturbances during dry periods because a loss of suitable refuges can affect the ability of some macroinvertebrate taxa to recolonise after flow recovery.

Is the END (emulation of natural disturbance) a new beginning? A critical analysis of the use of fire regimes as the basis of forest ecosystem management with examples from the Canadian western Cordillera

2016 ◽  
Vol 24 (3) ◽  
pp. 233-243 ◽  
Author(s):  
Chris Stockdale ◽  
Mike Flannigan ◽  
Ellen Macdonald
Keyword(s):  
Forest Management ◽  
Ecosystem Management ◽  
Forest Structure ◽  
Fire Regime ◽  
Natural Disturbance ◽  
Fire Regimes ◽  
Disturbance Regime ◽  
Ecological Processes ◽  
High Severity ◽  
Management Actions

As our view of disturbances such as wildfire has shifted from prevention to recognizing their ecological necessity, so too forest management has evolved from timber-focused even-aged management to more holistic paradigms like ecosystem-based management. Emulation of natural disturbance (END) is a variant of ecosystem management that recognizes the importance of disturbance for maintaining ecological integrity. For END to be a successful model for forest management we need to describe disturbance regimes and implement management actions that emulate them, in turn achieving our objectives for forest structure and function. We review the different components of fire regimes (cause, frequency, extent, timing, and magnitude), we describe low-, mixed-, and high-severity fire regimes, and we discuss key issues related to describing these regimes. When characterizing fire regimes, different methods and spatial and temporal extents result in wide variation of estimates for different fire regime components. Comparing studies is difficult as few measure the same components; some methods are based on the assumption of a high-severity fire regime and are not suited to detecting mixed- or low-severity regimes, which are critical to END management, as this would affect retention in harvested areas. We outline some difficulties with using fire regimes as coarse filters for forest management, including (i) not fully understanding the interactions between fire and other disturbance agents, (ii) assuming that fire is strictly an exogenous disturbance agent that exerts top-down control of forest structure while ignoring numerous endogenous and bottom-up feedbacks on fire effects, and (iii) assuming by only replicating natural disturbance patterns we preserve ecological processes and vital ecosystem components. Even with a good understanding of a fire regime, we would still be challenged with choosing the temporal and spatial scope for the disturbance regime we are trying to emulate. We cannot yet define forest conditions that will arise from variations in disturbance regime; this then limits our ability to implement management actions that will achieve those conditions. We end by highlighting some important knowledge gaps about fire regimes and how the END model could be strengthened to achieve a more sustainable form of forest management.

scholarly journals Rabies Surveillance Identifies Potential Risk Corridors and Enables Management Evaluation

Viruses ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1006 ◽  
Author(s):  
Amy J. Davis ◽  
Kathleen M. Nelson ◽  
Jordona D. Kirby ◽  
Ryan Wallace ◽  
Xiaoyue Ma ◽  
...  
Keyword(s):  
United States ◽  
Potential Risk ◽  
Management Strategies ◽  
Habitat Type ◽  
The United States ◽  
Management Program ◽  
United States Department ◽  
Eastern United States ◽  
Management Actions ◽  
Health Surveillance Data

Intensive efforts are being made to eliminate the raccoon variant of rabies virus (RABV) from the eastern United States and Canada. The United States Department of Agriculture (USDA) Wildlife Services National Rabies Management Program has implemented enhanced rabies surveillance (ERS) to improve case detection across the extent of the raccoon oral rabies vaccination (ORV) management area. We evaluated ERS and public health surveillance data from 2006 to 2017 in three northeastern USA states using a dynamic occupancy modeling approach. Our objectives were to examine potential risk corridors for RABV incursion from the U.S. into Canada, evaluate the effectiveness of ORV management strategies, and identify surveillance gaps. ORV management has resulted in a decrease in RABV cases over time within vaccination zones (from occupancy ( ψ ¯ ) of 0.60 standard error (SE) = 0.03 in the spring of 2006 to ψ ¯ of 0.33 SE = 0.10 in the spring 2017). RABV cases also reduced in the enzootic area (from ψ ¯ of 0.60 SE = 0.03 in the spring of 2006 to ψ ¯ of 0.45 SE = 0.05 in the spring 2017). Although RABV occurrence was related to habitat type, greater impacts were associated with ORV and trap–vaccinate–release (TVR) campaigns, in addition to seasonal and yearly trends. Reductions in RABV occupancy were more pronounced in areas treated with Ontario Rabies Vaccine Bait (ONRAB) compared to RABORAL V-RG®. Our approach tracked changes in RABV occurrence across space and time, identified risk corridors for potential incursions into Canada, and highlighted surveillance gaps, while evaluating the impacts of management actions. Using this approach, we are able to provide guidance for future RABV management.

scholarly journals Effect of Hyporheic Exchange on Macroinvertebrate Community in the Weihe River Basin, China

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 457
Author(s):  
Qidong Lin ◽  
Jinxi Song ◽  
Carlo Gualtieri ◽  
Dandong Cheng ◽  
Ping Su ◽  
...  
Keyword(s):  
River Basin ◽  
Transport Processes ◽  
Macroinvertebrate Community ◽  
Hyporheic Exchange ◽  
Macroinvertebrate Communities ◽  
Fine Grained ◽  
River Bed ◽  
Weihe River ◽  
Abundance And Diversity ◽  
Weihe River Basin

The effect of hyporheic exchange on macroinvertebrates is a significant topic in ecohydraulics. A field study was conducted during May and June 2017 to investigate the impacts of magnitude and patterns of hyporheic exchange on the sediment macroinvertebrate community in the Weihe River basin. The results demonstrate that upwelling flows cause resuspension of riverbed sediment, increasing the proportion of swimmer groups (such as Baetidae) in the macroinvertebrate community. However, large resuspension of river bed sediment results in a reduced abundance of macroinvertebrates. By controlling the transport processes of dissolved oxygen (DO), dissolved organic carbon (DOC), nutrients, temperature, and different patterns of hyporheic exchange strongly influence the structure of macroinvertebrate communities. Downwelling is more likely to produce rich invertebrate communities than upwelling. The magnitude for the hyporheic flux of 150–200 mm/d was optimal for the macroinvertebrate community in the Weihe River Basin. Above or below this rate results in a decline in community abundance and diversity. We suggest that research is conducted to better understand the effects of hyporheic exchange across bedforms on macroinvertebrate communities. The study supports any activities to preserve the ecological functions and health of rivers dominated by fine-grained sediments.

scholarly journals Assessing macroinvertebrate communities in relation to environmental variables: the case of Sambandou wetlands, Vhembe Biosphere Reserve

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Tatenda Dalu ◽  
Rivoningo Chauke
Keyword(s):  
Community Structure ◽  
Water Depth ◽  
Environmental Variables ◽  
Anthropogenic Activities ◽  
Biosphere Reserve ◽  
High Water ◽  
Macroinvertebrate Community ◽  
Macroinvertebrate Communities ◽  
Negative Effect ◽  
Macrophyte Cover

AbstractThe Vhembe Biosphere Reserve, South Africa, contains many wetlands that serve as wildlife habitats and provide vital ecosystem services. Some of the wetlands are continuously being degraded or destroyed by anthropogenic activities causing them to disappear at an alarming rate. Benthic macroinvertebrates are known as good water quality bioindicators and are used to assess aquatic ecosystem health. The current study investigated habitat quality using macroinvertebrate community structure and other biotic variables (i.e. phytoplankton, macrophytes) in relation to environmental variables in the Sambandou wetlands using canonical correspondence analysis (CCA). A total of fifteen macroinvertebrate families were identified over two seasons. The CCA highlighted seven variables, i.e. pH, phosphate concentration, temperature, ammonium, macrophyte cover, conductivity and water depth, which were significant in structuring macroinvertebrate community. Picophytoplankton and microphytoplankton concentrations decreased from winter to summer, whereas nanophytoplankton concentration increased from winter to summer. Thus, the dominance of small-sized phytoplankton indicated nutrient limitation and decreased productivity, whereas winter sites 2 and 3 were dominated by large-celled phytoplankton, highlighting increased productivity. Winter sites were mostly negatively associated with CCA axis 1 and were characterised by high temperature, phosphate and ammonium concentrations, macrophyte cover, pH and conductivity. Summer sites were positively associated with axis 1, being characterised by high water depth and pH levels. The results obtained highlighted that agricultural activities such as cattle grazing and crop farming and sand mining/poaching had a negative effect on macroinvertebrate community structure.

scholarly journals A game theory model for gut bacterial nutrient utilization strategies during human infancy

2020 ◽  
Vol 287 (1931) ◽  
pp. 20200824 ◽  
Author(s):  
Inga Leena Angell ◽  
Knut Rudi
Keyword(s):  
Game Theory ◽  
Gut Microbiota ◽  
Nutrient Utilization ◽  
Theory Model ◽  
Ecological Processes ◽  
Β Diversity ◽  
Gut Colonization ◽  
Α Diversity ◽  
Colonization Patterns ◽  
Expanding Population

Despite the fact that infant gut colonization patterns have been extensively studied, we have limited knowledge about the underlying ecological processes. This particularly relates to the ecological choice of nutrient utilization strategies. The aim of the current study was therefore to compare empirically determined nutrient utilization strategies with that expected from a combinatorial game theory model. Observational analyses for 100 mother–child pairs suggested mother–child transmission of specialists with the potential to use few nutrients. Generalists, on the other hand, with the potential to use many nutrients, peaked at three months of age for the children. The level of generalists was gradually replaced with specialists up to 12 months of age. Game theory simulation revealed a competitive advantage of generalists in an expanding population, while more specialized bacteria were favoured with the maturation of the population. This suggests that the observed increase in generalists in the three-month-old children could be due to an immature, expanding gut microbiota population while the increase of specialists at 12 months could be due to population maturation. The simulated and empirical data also correspond with respect to an increased α diversity and a decreased β diversity with the number of simulations and age, respectively. Taken together, game theory simulation of nutrient utilization strategies can therefore provide novel insight into the maturation of the human gut microbiota during infancy.

Environmental heterogeneity and β diversity of stream macroinvertebrate communities at intermediate spatial scales

2013 ◽  
Vol 32 (1) ◽  
pp. 142-154 ◽  
Author(s):  
Jani Heino ◽  
Mira Grönroos ◽  
Jari Ilmonen ◽  
Tommi Karhu ◽  
Maija Niva ◽  
...  
Keyword(s):  
Environmental Heterogeneity ◽  
Spatial Scales ◽  
Macroinvertebrate Communities ◽  
Β Diversity ◽  
Stream Macroinvertebrate

scholarly journals Walking on their own legs: unassisted population growth of the agouti Dasyprocta leporina, reintroduced to restore seed dispersal in an Atlantic Forest reserve

Oryx ◽  
2017 ◽  
Vol 52 (3) ◽  
pp. 571-578 ◽  
Author(s):  
Caio Fittipaldi Kenup ◽  
Raíssa Sepulvida ◽  
Catharina Kreischer ◽  
Fernando A. S. Fernandez
Keyword(s):  
Seed Dispersal ◽  
Cost Effective ◽  
Medium Term ◽  
Scatter Hoarding ◽  
Ecological Processes ◽  
Neotropical Forests ◽  
Forest Reserve ◽  
Management Actions ◽  
Reintroduced Population ◽  
Log Normal

AbstractReintroduction of locally extirpated species is an increasingly popular conservation tool. However, few initiatives focus on the restoration of ecological processes. In addition, many reintroductions fail to conduct post-release monitoring, hampering both assessment of their success and implementation of adaptive management actions. In 2009 a reintroduction effort was initiated to re-establish a population of the red-rumped agouti Dasyprocta leporina, a scatter-hoarding rodent known to be an important disperser of large seeds, with the aim of restoring ecological processes at Tijuca National Park, south-east Brazil. To assess whether this reintroduced population established successfully we monitored it using mark–resighting during November 2013–March 2015. Population size and survival were estimated using a robust design Poisson-log normal mixed-effects mark–resight model. By March 2015 the number of wild-born individuals fluctuated around 30 and overall growth of the population was positive. As the reintroduced population is capable of unassisted growth, we conclude that the reintroduction has been successful in the medium term. We recommend the cessation of releases, with efforts redirected to continued monitoring, investigation and management of possible threats to the species’ persistence, and to quantification of the re-establishment of ecological processes. Reintroduction of D. leporina populations can be a cost-effective tool to restore ecological processes, especially seed dispersal, in Neotropical forests.

The additive partitioning of macroinvertebrate diversity in tropical reservoirs

2013 ◽  
Vol 64 (7) ◽  
pp. 609 ◽  
Author(s):  
Joseline Molozzi ◽  
Luiz U. Hepp ◽  
Marcos Callisto
Keyword(s):  
Total Variation ◽  
Environmental Variability ◽  
Spatial Scales ◽  
Spatial Diversity ◽  
Mantel Test ◽  
Additive Partitioning ◽  
Spatial Partitioning ◽  
Biological Matrix ◽  
Tropical Reservoirs ◽  
Β Diversity

Understanding the ways in which diversity changes across spatial scales is important for the conservation of biodiversity. The objectives of the present study were (1) to characterise the diversity of aquatic macroinvertebrates in three Brazilian tropical reservoirs and (2) to determine how the organisms were distributed at different spatial scales, by using a diversity partitioning approach. We compared the diversity-partition results with the null hypothesis that the macroinvertebrate community was uniform across all spatial scales in the study. We expected that differences in environmental variability (sediment characteristics) among the reservoirs and limitations on the dispersal of organisms among reservoirs result in higher biological variability (β diversity). The results of the spatial partitioning analysis of species richness in the reservoirs showed that each Ekman–Birge dredge-sampling unit (α) represented 43.7% of the total variation. β1 diversity (diversity among Ekman–Birge dredge-sampling units) represented 47.2% of the total variation. A partial Mantel test indicated a correlation between the particle-size matrix and the biological matrix. However, the biological matrix was not correlated with the geographical matrix. The partitioning of overall spatial diversity indicated that the distribution of species in the reservoirs was driven by local factors and that diversity was more pronounced at lower hierarchical levels.

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