Are invasive hymenopteran species replacing native mud dauber wasp-associated taxa on the Seychelles Archipelago?

Nest aggregations of mud dauber wasps increase substrate heterogeneity and provide suitable sites for colonization by other invertebrate species. The mud dauber wasp Sceliphron fuscum Klug, 1801 (Hymenoptera: Sphecidae) abundantly occurs throughout the Seychelles Archipelago, Republic of Seychelles. Here, we estimated the taxonomic richness of the hymenopteran assemblage associated with S. fuscum’s nest aggregations, using material collected from the Inner Seychelles in 2016. Furthermore, we examine available historical survey data in order to assess possible changes in this association over decades. We discovered that from 1936 to 1938, seven hymenopteran species were associated with the nest aggregations of S. fuscum on Mahé and Praslin islands, representing six native taxa and one invasive species. From the material collected in 2016, we found one native and three invasive hymenopteran species associated to S. fuscum nests. Our findings could indicate a replacement of native species associated with the mud dauber wasps’ nest aggregations by recently introduced alien taxa on the Seychelles Archipelago.

High Incidence of Strawberry Polerovirus 1 in the Czech Republic and Its Vectors, Genetic Variability and Recombination

In total, 332 strawberry plants from 33 different locations in the Czech Republic with or without disease symptoms were screened by RT-PCR for the presence of strawberry polerovirus 1 (SPV1) and five other viruses: strawberry mottle virus, strawberry crinkle virus, strawberry mild yellow edge virus, strawberry vein banding virus, and strawberry virus 1. SPV1 was detected in 115 tested strawberry plants (35%), including 89 mixed infections. No correlation between symptoms and the detected viruses was found. To identify potential invertebrate SPV1 vectors, strawberry-associated invertebrate species were screened by RT-PCR, and the virus was found in the aphids Aphis forbesi, A. gossypii, A. ruborum, A.sanquisorbae, Aulacorthum solani, Chaetosiphon fragaefolii, Myzus ascalonicus, and several other non-aphid invertebrate species. SPV1 was also detected in aphid honeydew. Subsequent tests of C. fragaefolii and A.gossypii virus transmission ability showed that at least 4 h of acquisition time were needed to acquire the virus. However, 1 day was sufficient for inoculation using C. fragaefolii. In conclusion, being aphid-transmitted like other tested viruses SPV1 was nevertheless the most frequently detected agent. Czech SPV1 isolates belonged to at least two phylogenetic clusters. The sequence analysis also indicated that recombination events influence evolution of SPV1 genomes.

Verification of Hypsibius exemplaris Gąsiorek et al., 2018 (Eutardigrada; Hypsibiidae) application in anhydrobiosis research

Anhydrobiosis is considered to be an adaptation of important applicative implications because it enables resistance to the lack of water. The phenomenon is still not well understood at molecular level. Thus, a good model invertebrate species for the research is required. The best known anhydrobiotic invertebrates are tardigrades (Tardigrada), considered to be toughest animals in the world. Hypsibius. exemplaris is one of the best studied tardigrade species, with its name “exemplaris” referring to the widespread use of the species as a laboratory model for various types of research. However, available data suggest that anhydrobiotic capability of the species may be overestimated. Therefore, we determined anhydrobiosis survival by Hys. exemplaris specimens using three different anhydrobiosis protocols. We also checked ultrastructure of storage cells within formed dormant structures (tuns) that has not been studied yet for Hys. exemplaris. These cells are known to support energetic requirements of anhydrobiosis. The obtained results indicate that Hys. exemplaris appears not to be a good model species for anhydrobiosis research.

Assessing ecological patterns in Wellington south coast's nearshore rocky-reef communities for resource conservation and management

<p>Many coastal marine communities are increasingly affected by terrestrial and maritime human activities and growing coastal populations. Protection of coastal assets and the sustainable use of coastal resources requires knowledge of nearshore benthic community status; the environmental processes that structure and connect them; the quality, abundance, and distribution of physical habitat; essential habitat for species requiring protective measures, and the spatio-temporal scales at which these patterns and processes occur. To assess the status of Wellington South Coast’s (WSC) rocky-reef assemblages prior to the enactment of the Taputeranga Marine Reserve in 2009, two annual baseline surveys were conducted during the austral summers of 2007/08 and 2008/09. These surveys evaluated the biotic and abiotic components of the assemblages in terms of diversity, abundance distribution, and size-class frequency patterns of key macroalgal and mobile macro-invertebrate species. These results were analysed to develop recommendations for best post-reserve monitoring practices, including the identification of “indicator” species for rapid yet representative field surveys to assess structural and status changes. In combination with patterns described by a previous pre-reserve baseline survey series (2000) that focussed on a reduced list of macro-algal and mobile macro-invertebrate species, this final pre-reserve survey forms the basis of a historical dataset for WSC rocky reefs that can be used for long-term monitoring of ecosystem shifts due to the new reserve and to possible changes caused by anthropogenic activity or altered natural processes. These aims were addressed by collecting information directly at local/site scale and remotely, at the larger area scale. Dived baseline surveys quantified nearshore WSC rocky-reef epibenthic assemblages at 9 sites at depths ranging from 5-13.6m and at a mean distance from shore = 113m. A survey design that included three sites west of the pending marine reserve, three sites to the east, and three sites within the designated reserve was selected to permit later BACI analyses of post-reserve changes. Species surveyed were those commonly encountered during daylight on exposed surfaces and in accessible crevices and belonged to one of three epibenthic groups: macro-algae (48 species), mobile macro-invertebrates (36 species), and sessile macro-invertebrates (30 morphotypes). These surveys did not include epizoa or smaller, cryptic newly recruited macro-invertebrates. Sessile macro-invertebrate cover was only logged if >0.1%/m2. To gauge possible spatio-temporal patterns in primary productivity as a measure of ecosystem function, biomass and plant size were measured semiannually (winter, summer) for dominant kelp and fucoid species and for two key recreationally and commercially important mobile macro-invertebrate species (sea urchin and abalone). Predictive regression equations developed from wet weight and plant size can be used for future non-destructive estimates of local primary productivity and in trophic modelling. [...] This mapping data forms the basis of a legacy dataset that will assist with monitoring changes in the integrity of critical physical habitat and associated biotic cover. It has also demonstrated that representative descriptions of both biotic and abiotic benthic components can be achieved with a minimum of sampling points and by using the quicker semi-quantitative visual analysis of video. These data can also be used to ground-truth a recently-completed multi-beam acoustic survey of the area. This work has used the approach of landscape ecology, which explains patterns in community structure, function, status and biophysical causes from a spatial perspective, to study biophysical patterns in WSC epibenthic rocky-reef communities. The work identified a high degree of spatial and temporal variation within the abiotic and biotic community within and outside of the reserve area and the limited availability of preferred habitat. The work also identified the need to include indicator species in monitoring to improve the chance of detecting impacted assemblages. These results, and the development of non-destructive sampling tools for assessing ecosystem status, are relevant locally and nationally for resource managers.</p>

Assessing ecological patterns in Wellington south coast's nearshore rocky-reef communities for resource conservation and management

<p>Many coastal marine communities are increasingly affected by terrestrial and maritime human activities and growing coastal populations. Protection of coastal assets and the sustainable use of coastal resources requires knowledge of nearshore benthic community status; the environmental processes that structure and connect them; the quality, abundance, and distribution of physical habitat; essential habitat for species requiring protective measures, and the spatio-temporal scales at which these patterns and processes occur. To assess the status of Wellington South Coast’s (WSC) rocky-reef assemblages prior to the enactment of the Taputeranga Marine Reserve in 2009, two annual baseline surveys were conducted during the austral summers of 2007/08 and 2008/09. These surveys evaluated the biotic and abiotic components of the assemblages in terms of diversity, abundance distribution, and size-class frequency patterns of key macroalgal and mobile macro-invertebrate species. These results were analysed to develop recommendations for best post-reserve monitoring practices, including the identification of “indicator” species for rapid yet representative field surveys to assess structural and status changes. In combination with patterns described by a previous pre-reserve baseline survey series (2000) that focussed on a reduced list of macro-algal and mobile macro-invertebrate species, this final pre-reserve survey forms the basis of a historical dataset for WSC rocky reefs that can be used for long-term monitoring of ecosystem shifts due to the new reserve and to possible changes caused by anthropogenic activity or altered natural processes. These aims were addressed by collecting information directly at local/site scale and remotely, at the larger area scale. Dived baseline surveys quantified nearshore WSC rocky-reef epibenthic assemblages at 9 sites at depths ranging from 5-13.6m and at a mean distance from shore = 113m. A survey design that included three sites west of the pending marine reserve, three sites to the east, and three sites within the designated reserve was selected to permit later BACI analyses of post-reserve changes. Species surveyed were those commonly encountered during daylight on exposed surfaces and in accessible crevices and belonged to one of three epibenthic groups: macro-algae (48 species), mobile macro-invertebrates (36 species), and sessile macro-invertebrates (30 morphotypes). These surveys did not include epizoa or smaller, cryptic newly recruited macro-invertebrates. Sessile macro-invertebrate cover was only logged if >0.1%/m2. To gauge possible spatio-temporal patterns in primary productivity as a measure of ecosystem function, biomass and plant size were measured semiannually (winter, summer) for dominant kelp and fucoid species and for two key recreationally and commercially important mobile macro-invertebrate species (sea urchin and abalone). Predictive regression equations developed from wet weight and plant size can be used for future non-destructive estimates of local primary productivity and in trophic modelling. [...] This mapping data forms the basis of a legacy dataset that will assist with monitoring changes in the integrity of critical physical habitat and associated biotic cover. It has also demonstrated that representative descriptions of both biotic and abiotic benthic components can be achieved with a minimum of sampling points and by using the quicker semi-quantitative visual analysis of video. These data can also be used to ground-truth a recently-completed multi-beam acoustic survey of the area. This work has used the approach of landscape ecology, which explains patterns in community structure, function, status and biophysical causes from a spatial perspective, to study biophysical patterns in WSC epibenthic rocky-reef communities. The work identified a high degree of spatial and temporal variation within the abiotic and biotic community within and outside of the reserve area and the limited availability of preferred habitat. The work also identified the need to include indicator species in monitoring to improve the chance of detecting impacted assemblages. These results, and the development of non-destructive sampling tools for assessing ecosystem status, are relevant locally and nationally for resource managers.</p>

A Quantitative Assessment of Ra'ui (a Traditional Approach to Marine Protected Areas) on the Fishes and Invertebrates of Rarotonga, Cook Islands

<p>Ra'ui (traditional marine managed areas) in Rarotonga, Cook Islands, are a form of marine protected area re-implemented in the late 1990s when communities became concerned about declining fish and invertebrate stocks in the lagoon. In this thesis I quantified the effects of Ra'ui on fish and invertebrates. First, for a single focal species of abundant reef fish (Ctenochaetus striatus), I developed a novel framework to incorporate environmental heterogeneity into a Control-Impact assessment of Ra'ui effectiveness using an index of habitat selectivity (Manly's alpha) to 'adjust' the density of a reef fish by 'preferred' substrates. My results empirically demonstrated that substrate heterogeneity impinged upon the interpretation of MPA effects. This suggests that habitat heterogeneity should be quantitatively incorporated into analyses of MPA effects to provide a more robust and defensible set of inferences. The novel framework was then used to assess the effects of Ra'ui on densities of other common reef fish and invertebrates, as well as fish functional groups. Averaged across all Ra'ui, a higher percentage of the invertebrate species (20%) had greater abundances inside Ra'ui relative to corresponding Control sites than fish species (15%). This may suggest spatial management is more effective for sessile organisms such as the invertebrates in this study. Even when environmental heterogeneity was 'controlled' in my analyses, responses to Ra'ui were variable between species and sites, illustrating that factors other than environmental heterogeneity may be driving varying patterns of species abundances. However, for the broad-scale functional groups, there were indications of inverse relationships between predator and prey functional groups at 3 of the Ra'ui. I applied meta-analytical techniques to my data to assess whether there was an island-wide effect of Ra'ui on the densities of fish and invertebrate species, and functional groups. There was no evidence in the metaanalyses for an island-wide Ra'ui effect for any species or functional groups. However, analysis of covariance suggested there was an island-wide Ra'ui effect for a number of fish and invertebrate species. The body size of fish and invertebrates is another metric of MPA effectiveness that is expected to increase with protection. However, in determining an island-wide effect of Ra'ui on size, only two fish species, Mulloidichthys flavolineatus and Stegastes nigricans, had greater mean size in Ra'ui relative to Control sites, and Siganus argenteus was the only reef fish to exhibit greater maximum size in the Ra'ui. Two of the lagoon invertebrates (Echinometra mathaei and Tripneustes gratilla) and three of the reefcrest invertebrates (Echinothrix diadema, Echinometra oblonga, and Trochus niloticus) exhibited an island-wide positive response to Ra'ui for mean size. At individual Ra'ui sites, a number of invertebrates had greater mean and maximum size. Further, at individual sites, M. flavolineatus had greater mean size across the most Ra'ui (4 sites), again indicating that the site fidelity of a species may influence its response to protection. Ontogenetic shifts in habitat use are known to occur in fish and invertebrates. For five fish species, juveniles used habitat differently to adults of the same species. Further, of the five species, only densities of both juvenile and adult Acanthurus triostegus exhibited a positive relationship with the proportion of their preferred habitat (juveniles: r2 = 0.44, p = 0.011; adults: r2 = 0.46, p = 0.009). Densities of adult Ctenochaetus striatus also increased linearly with the proportion of preferred substrate cover (r2 = 0.43, p = 0.035). These results suggest that habitat within an MPA may be limiting for different benthic stages of an organism's ontogeny. Some knowledge of the characteristics that underpin MPA effectiveness can aid in their design. Using commonly occurring fish and invertebrate species, I explored the effectiveness of individual Ra'ui using three separate metrics of effectiveness (the proportion of fish and invertebrates exhibiting 1) greater densities, 2) greater mean size, and 3) greater maximum size in Ra'ui relative to Control sites. Ra'ui area and total fish density in each Ra'ui were characteristics that best described the effectiveness of Ra'ui in enhancing mean fish and invertebrate size. The level of compliance with Ra'ui may also have some impact on Ra'ui effectiveness. This study highlights the importance of incorporating environmental heterogeneity into assessments of MPA effects. Further, temporary prohibitions such as Ra'ui may be more effective for some species if certain conditions are met e.g., compliance is good, and the species Ra'ui are protecting / enhancing have high site-fidelity and high growth rates. These findings provide important information for fisheries and conservation managers (e.g., traditional leaders, governmental agencies, non-governmental agencies, communities) that will aid in better design of monitoring programmes and facilitate improved MPA design, not only in the Pacific region, but worldwide.</p>

A Quantitative Assessment of Ra'ui (a Traditional Approach to Marine Protected Areas) on the Fishes and Invertebrates of Rarotonga, Cook Islands

<p>Ra'ui (traditional marine managed areas) in Rarotonga, Cook Islands, are a form of marine protected area re-implemented in the late 1990s when communities became concerned about declining fish and invertebrate stocks in the lagoon. In this thesis I quantified the effects of Ra'ui on fish and invertebrates. First, for a single focal species of abundant reef fish (Ctenochaetus striatus), I developed a novel framework to incorporate environmental heterogeneity into a Control-Impact assessment of Ra'ui effectiveness using an index of habitat selectivity (Manly's alpha) to 'adjust' the density of a reef fish by 'preferred' substrates. My results empirically demonstrated that substrate heterogeneity impinged upon the interpretation of MPA effects. This suggests that habitat heterogeneity should be quantitatively incorporated into analyses of MPA effects to provide a more robust and defensible set of inferences. The novel framework was then used to assess the effects of Ra'ui on densities of other common reef fish and invertebrates, as well as fish functional groups. Averaged across all Ra'ui, a higher percentage of the invertebrate species (20%) had greater abundances inside Ra'ui relative to corresponding Control sites than fish species (15%). This may suggest spatial management is more effective for sessile organisms such as the invertebrates in this study. Even when environmental heterogeneity was 'controlled' in my analyses, responses to Ra'ui were variable between species and sites, illustrating that factors other than environmental heterogeneity may be driving varying patterns of species abundances. However, for the broad-scale functional groups, there were indications of inverse relationships between predator and prey functional groups at 3 of the Ra'ui. I applied meta-analytical techniques to my data to assess whether there was an island-wide effect of Ra'ui on the densities of fish and invertebrate species, and functional groups. There was no evidence in the metaanalyses for an island-wide Ra'ui effect for any species or functional groups. However, analysis of covariance suggested there was an island-wide Ra'ui effect for a number of fish and invertebrate species. The body size of fish and invertebrates is another metric of MPA effectiveness that is expected to increase with protection. However, in determining an island-wide effect of Ra'ui on size, only two fish species, Mulloidichthys flavolineatus and Stegastes nigricans, had greater mean size in Ra'ui relative to Control sites, and Siganus argenteus was the only reef fish to exhibit greater maximum size in the Ra'ui. Two of the lagoon invertebrates (Echinometra mathaei and Tripneustes gratilla) and three of the reefcrest invertebrates (Echinothrix diadema, Echinometra oblonga, and Trochus niloticus) exhibited an island-wide positive response to Ra'ui for mean size. At individual Ra'ui sites, a number of invertebrates had greater mean and maximum size. Further, at individual sites, M. flavolineatus had greater mean size across the most Ra'ui (4 sites), again indicating that the site fidelity of a species may influence its response to protection. Ontogenetic shifts in habitat use are known to occur in fish and invertebrates. For five fish species, juveniles used habitat differently to adults of the same species. Further, of the five species, only densities of both juvenile and adult Acanthurus triostegus exhibited a positive relationship with the proportion of their preferred habitat (juveniles: r2 = 0.44, p = 0.011; adults: r2 = 0.46, p = 0.009). Densities of adult Ctenochaetus striatus also increased linearly with the proportion of preferred substrate cover (r2 = 0.43, p = 0.035). These results suggest that habitat within an MPA may be limiting for different benthic stages of an organism's ontogeny. Some knowledge of the characteristics that underpin MPA effectiveness can aid in their design. Using commonly occurring fish and invertebrate species, I explored the effectiveness of individual Ra'ui using three separate metrics of effectiveness (the proportion of fish and invertebrates exhibiting 1) greater densities, 2) greater mean size, and 3) greater maximum size in Ra'ui relative to Control sites. Ra'ui area and total fish density in each Ra'ui were characteristics that best described the effectiveness of Ra'ui in enhancing mean fish and invertebrate size. The level of compliance with Ra'ui may also have some impact on Ra'ui effectiveness. This study highlights the importance of incorporating environmental heterogeneity into assessments of MPA effects. Further, temporary prohibitions such as Ra'ui may be more effective for some species if certain conditions are met e.g., compliance is good, and the species Ra'ui are protecting / enhancing have high site-fidelity and high growth rates. These findings provide important information for fisheries and conservation managers (e.g., traditional leaders, governmental agencies, non-governmental agencies, communities) that will aid in better design of monitoring programmes and facilitate improved MPA design, not only in the Pacific region, but worldwide.</p>

A Roadmap for the Restoration of Mediterranean Macroalgal Forests

Canopy-forming macroalgae play a crucial role in coastal primary production and nutrient cycling, providing food, shelter, nurseries, and habitat for many vertebrate and invertebrate species. However, macroalgal forests are in decline in various places and natural recovery is almost impossible when populations become locally extinct. Hence, active restoration emerges as the most promising strategy to rebuild disappeared forests. In this regard, significant efforts have been made by several EU institutions to research new restoration tools for shallow and mesophotic reef habitats (e.g., MERCES EU project, AFRIMED, and ROCPOP-life) and effective techniques have subsequently been proposed to promote self-sustaining populations. Recent research indicates that macroalgal forest recovery requires a broad spectrum of measures, ranging from mitigating human impacts to restoring the most degraded populations and habitats, and that the viability of large restoration actions is compromised by ongoing human pressures (e.g., pollution, overgrazing, and climate change). We propose a roadmap for Mediterranean macroalgal restoration to assist researchers and stakeholders in decision-making, considering the most effective methods in terms of cost and cost-effectiveness, and taking background environmental conditions and potential threats into account. Last, the challenges currently faced by the restoration of rocky coastal ecosystems under changing climate conditions are also discussed.