Habitat configuration for an obligate shallow‐water delphinid: The Indo‐Pacific humpback dolphin,Sousa chinensis,in the Beibu Gulf (Gulf of Tonkin)

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The Kaikōura earthquake in southern New Zealand: Loss of connectivity of marine communities and the necessity of a cross‐ecosystem perspective

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You cannot conserve a species that has not been found: The case of the marine sponge Axinella polypoides in Liguria,Italy

1. Detailed knowledge about the distribution of species in need of protection is required for the management of Marine Protected Areas, a major tool to reduce marine biodiversity loss. Such knowledge is deficient for most marine invertebrates.
2. Axinella polypoides is a marine sponge included on the list of protected species by the Barcelona Convention (1976) and the Bern Convention (1987). This large and erect species has an important ecological role in habitat forming and benthic–pelagic coupling.
3. Bathymetrical, geographical and ecological data over the last 60 years were collated from publications and reports, together with new surveys to assess the distribution and protection status in Liguria of A. polypoides. It identified a more widespread distribution than previously thought, which points at a general need for dedicated investigations on the occurrence of species that require protection.
4. Bathymetrical distribution was trimodal, with peaks corresponding to different geomorphological settings: coastal cliff bases (around 38 m depth), inner shelf shoals (52 m) and rocks amidst coarse sediment on the outer shelf (79 m). Density was significantly greater at the shallowest depths. The species was mostly found in the coralligenous biocoenosis, in association with other characteristic species or forming a monospecific facies.
5. On (sub)vertical cliffs, A. polypoides often exhibited an unusual cane shape, rather than the typical bushy morphology, thus causing confusion with the congeneric A. cannabina, a more southern species. Records of the latter in the Ligurian Sea therefore need confirmation.
6. Only a minority (22.6%) of A. polypoides records were in Marine Protected Areas, the remainder being located in areas with no current environmental protection plans in place. While the occurrence of this species in MPAs remained stable over the decades, the only quantitative historical data available indicated that populations in non-protected areas were declining owing to anthropogenic impacts (fishing and anchoring).

     

Bonefish (Albula vulpes) home range to spawning site linkages support a marine protected area designation

1. A spatial approach to coastal management, such as marine protected areas, is being increasingly used to address biodiversity and fishery declines resulting from habitat loss, degradation, and overfishing. This approach is especially applicable in regions and fisheries that are data poor, and which often lack regulations and adequate capacity for enforcement. In data-poor situations, species that have economic, cultural, and charismatic value can provide leverage for ecosystem protection.
2. In this study, acoustic telemetry was used to confirm a pre-spawning aggregation site, acting as critical information for protection of essential habitat for bonefish. Additionally, data sharing with an acoustic telemetry study on smalltooth sawfish (Pristis pectinata) documented linkages between the pre-spawning aggregation site and bonefish home ranges ≥70 km distant, thus providing an estimate of the catchment area.
3. These data provided post hoc support for a marine national park designated in 2002, and demonstrate that the park is of the appropriate spatial scale.

     

Rescue and relocation of benthic organisms during an urban‐port development project: Port of Manzanillo,case study

1. The present study originated with the expansion of the boardwalk within the urban and port area of Manzanillo, México. Prior to civil works related to the placement of tetrapods, surveys of potential sites for the relocation of benthic organisms in alternative areas were carried out.
2. Based on indicators of the physical–chemical environment and biotic factors, nine areas with potential for relocation were evaluated. The areas of greatest potential were associated with environments located away from the influence of the port environment.
3. A total of 13,559 benthic organisms belonging to 68 species associated with three main substratum types (rocky, sandy, and mixed) were collected. There were no differences in the ecological indices between the three substrata.
4. The proximity of the collection area to the influence of port traffic and sources of pollution associated with the physical environment could be an important factor that affects ecological indices and the reduction in the abundance of some protected species and species of commercial interest.
5. The success of collection and relocation processes depends on minimizing possible errors, especially during transportation, when overcrowding, handling, and damage resulting from variable physico‐chemical conditions should be avoided.
6. Through a scheme of actions based on ecological principles, management actions, and civil engineering technology, it was possible to carry out mitigation, conservation, and habitat improvement actions in coastal marine environments exposed to anthropogenic impacts.

     

Modelling the potential distribution of two tropical freshwater fish species under climate change scenarios

1. Climate change is causing shifts in the distribution patterns of freshwater fish at various spatio-temporal scales. Tropical freshwater fish are vulnerable, especially in areas where a high impact of climate change is predicted; thus, there is an increasing need to predict these shifts to determine conservation and adaptation strategies.
2. Ecological niche models offer a reliable way to predict the effects of climate change on species distribution. Potential shifts in the distribution of tropical fish were tested under two scenarios (4.5 – moderate and 8.5 – extreme) with three general circulation models for years 2050 and 2070 using maximum entropy software using as models two predatory species – the tropical gar Atractosteus tropicus and the giant cichlid Petenia splendida.
3. The potential distribution of both species was associated with warm and humid–sub-humid conditions. Future projections showed a higher availability of suitable areas for both species resulting from the expansion of warmer conditions in the middle and upper basins of the Central American mountain range and centre of the Yucatan Peninsula.
4. Ecological niche models of keystone or umbrella species such as A. tropicus and P. splendida could be useful to support conservation plans of protected areas. The potential distribution of both species covers areas of high suitability including six important biosphere reserves in Mexico, three protected areas in Guatemala and part of the Mesoamerican biological corridor.
5. Despite the potential expansion of the present distribution range suggested by the models, it is important to consider the biological and ecological requirements of the species and the ecological implications of these potential shifts in distribution. Both scenarios could have several implications at genetic, population, and ecosystem levels.

     

Long‐term habitat loss in a lightly‐disturbed population of the Indo‐Pacific humpback dolphin,Sousa chinensis

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A spatio‐temporal long‐term assessment on the ecological response of reef communities in a Caribbean marine protected area

1. Coral reef biodiversity is rapidly decreasing as a result of the loss of coral cover, which modifies the structure and functioning of the ecosystem. Understanding how coral reef communities respond in space and over the long term is essential in order to implement management strategies and reduce the effects of biodiversity loss on coral reefs.
2. Fish, coral, and algae communities were used as indicators to evaluate changes in coral reef systems. The variation of these communities was studied in a marine protected area composed of three management zones in Cozumel Coral Reef National Park in Quintana Roo, Mexico, over a period of 11 years (2004–2014). The following parameters were monitored annually: (i) total fish density; (ii) fish trophic group densities; (iii) species richness and three fish diversity indices; (iv) relative scleractinian coral cover; and (v) relative macroalgae cover.
3. In the years in which coastal development, such as the construction of a marina, took place, an increase in the abundance of territorial herbivorous and planktivorous fish was observed. As the coral recovered, macrocarnivores and sessile benthic invertivores were re‐established, whereas scraper herbivores showed no changes in the period of study in any of the three management zones.
4. Coral cover recovery showed rapid phase‐shift reversal (phase‐shift, macroalgae dominance over coral) in the three zones. Even though the fish density and coral cover recovered, the diversity indices of each fish trophic group exhibited a reduction in the three management zones over time.

     

Comparing the stability of successional transient models in kelp forests and barrens (south-east Pacific): Implications for conservation monitoring

1. Ecological stability based on statistical variability was contrasted with the asymptotical local stability of transient states during successional changes in community structure in kelp forests and barren grounds.
2. Simplified semi-quantitative ecological models with different levels of complexity were constructed to represent transient successional states in kelp and barrens, and Routh–Hurwitz's criteria and Levins' criterion of local stability were also estimated.
3. The results suggest that ecological stability based on statistical variation does not match local (mathematical) stability, since although successional changes in kelp exhibited less variability (measured as percentage coefficient of variation), barren beds were more locally stable. The local stability criteria used in the current work could be a suitable technique for evaluating the likelihood of transient ecological states to resist or change, since it considers states at equilibrium to maintain their properties only against small disturbances.
4. These outcomes are relevant because the natural alternation between kelp and barrens could be disrupted by the intensive harvest of kelp species carried out over the last 10 years on the central-north Chilean coast and in other temperate ecosystems.
5. Additionally, the negative effects of harvesting kelp species could have a synergetic relationship with other drivers such as climate change and coastal pollution. Thus, strict policy managements to limit the kelp harvest are deeply encouraged. A monitoring programme for assessing the current conditions of benthic–pelagic ecosystems along the Chilean coast is also required.

     

Habitat protection actions for the Indo‐Pacific humpback dolphin: Baseline gaps,scopes, and resolutions for the Taiwanese subspecies

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Population genetic divergence of bonnethead sharks Sphyrna tiburo in the western North Atlantic: Implications for conservation

1. Sharks are a priority for conservation because numerous species, including small-sized coastal species, are being heavily exploited by commercial and recreational fisheries. Understanding the genetic population structure of sharks is key to effective management, maximizing their evolutionary potential in a rapidly changing environment and preventing population declines.
2. Limited dispersal is an important factor promoting population divergence for several coastal shark species. The genetic variation in 14 microsatellite loci and 21,006 single nucleotide polymorphisms genotyped using restriction-site-associated DNA sequencing was analysed to assess the genetic structure of the bonnethead shark, Sphyrna tiburo, in the western North Atlantic.
3. Genetic differences were identified among three well-defined regions: the western Florida coast, the south-eastern US Atlantic coast, and the southern Gulf of Mexico. Results support previous studies based on mitochondrial DNA sequences in defining differences among these regions and suggest limitations of bonnethead sharks in routinely performing long-distance migrations.
4. The limited connectivity among regions explains the pattern of genetic divergence but also reported divergence at the species/subspecies level. These genetically discrete bonnethead populations have independent evolutionary histories that may include local adaptations to specific areas.
5. Bonnethead sharks are currently managed as two stocks in the USA owing to recent genetic, tagging, and life history studies; however, no stock assessments or management plans exist for Mexico. These results not only serve to reinforce US management strategies and provide critical data about the extent of gene flow and sex dispersal among populations, but also begin the process of effective management in the waters of Mexico to ensure the long-term productivity and resilience of this species. With an absence of gene flow between populations from US waters and the southern Gulf of Mexico, there is a need for management plans based upon independent biological and population dynamics data since limited or no opportunities for populations to interchange individuals may occur to re-establish population viability.

     

Eroding diversity away: Impacts of a tetrapod breakwater on a subtropical coral reef

1. Artificial barriers for coastal protection have been deployed across numerous tropical and subtropical islands in the Pacific, including Okinawa Island, southern Japan, where artificial defences have been installed along a large part of the coastline.
2. Although artificial barriers can lead to beach narrowing or loss and can exacerbate erosion, their effects on coral reef ecosystems remain understudied.
3. This study investigated the impact of a tetrapod breakwater in Ogimi Village, Okinawa Island, Japan, comparing the area affected by the presence of the barrier with a nearby natural coastline, and examining differences in physical parameters (depth profiles, sediment granulometry, and erosion on plaster balls) and benthic community composition.
4. Significant differences in depth profiles, sediment granulometry, and erosion were found, suggestive of alterations in water energy levels (lower than controls on the landward side of the barrier, and higher on the seaward side).
5. The benthic community was also clearly affected, with almost no living corals growing over the blocks or in their proximity.
6. Overall, the data show how breakwaters can affect the physical environment and benthic communities in a subtropical coral reef ecosystem, with negative consequences for coral survival.

     

Gone with the wind: Seasonal distribution and habitat use by the reef manta ray (Mobula alfredi) in the Maldives,implications for conservation

1. Reef manta rays (Mobula alfredi) are one of the ocean's largest and most charismatic species. Pressure from targeted and bycatch fisheries coupled with their conservative life‐history traits including slow growth, late maturity, and low fecundity has led to catastrophic declines of the global population. The species is now listed as Vulnerable to Extinction on IUCN Red List of Threatened Species.
2. The global M. alfredi population is widely distributed in highly fragmented subpopulations. The Maldives supports the world's largest known subpopulation that undergoes seasonal migrations which are thought to be linked to peaks in ocean productivity induced by the South Asian Monsoon. Although the species is protected from targeted fisheries in the region, increasing pressures from habitat degradation and unsustainable tourism activities mean their effective conservation relies upon knowledge of the species' habitat use, seasonal distribution, and the environmental influences on such movements.
3. Photo‐ID sighting records collected between 2005 and 2017 were used to identify key aggregation sites throughout the archipelago, and multiple linear regression and prediction analysis identified the environmental variables affecting variations in the intra‐annual sighting frequency of M. alfredi.
4. Mobula alfredi were recorded at 273 different sites, 48 of which, with >100 sightings at each, were classified as key areas of habitat use. South‐west monsoon winds and chlorophyll‐a concentration predominantly affected the monthly percentage of M. alfredi sighted on the down‐current side of the atolls.
5. In a country where climate change and touristic pressure are increasingly threatening this species and its habitat, the identification of key areas of habitat use and temporal changes in the use of these sites highlight the areas that should be prioritized for protection enabling more effective conservation management.

     

Organic matter derived from kelp supports a large proportion of biomass in temperate rocky reef fish communities: Implications for ecosystem‐based management

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Conservation of Amazonian aquatic mammals

1. Aquatic mammals worldwide are highly threatened in freshwater ecosystems where they are affected by direct human activities (e.g. hunting) as well as indirect human alteration of freshwater ecosystems (e.g. dams, mining activity). Although aquatic mammals of the Amazon Basin are experiencing many growing threats, little is known about the escalating impacts on them, current limitations in protection mechanisms, and possible strategies to ensure their conservation. This study synthesizes the available information on Amazonian aquatic mammals, including the ecological characteristics of these species, key threats, population status and conservation prospects.
2. Amazonian aquatic mammals comprise seven species – Inia geoffrensis, Inia boliviensis, Inia araguaiaensis, Sotalia fluviatilis, Trichechus inunguis, Pteronura brasiliensis and Lontra longicaudis – which are characterized by low reproductive rates and keystone ecosystem roles. These species are endangered mainly by biological resource use, natural ecosystem modifications, energy production and mining, and climate change. Although information is sparse, there is evidence that these threats are inducing population declines of Inia spp., and hindering the recovery of populations of P. brasiliensis.
3. Protection mechanisms for these species mostly include national and international laws and agreements, legislation governing environmental licensing and protected areas. Each of these protection mechanisms, however, has limited capacity to protect Amazonian aquatic mammals, largely because they are poorly enforced, lack transnational coordination or require population trend data that do not exist.
4. Reversing the current state of affairs for Amazonian aquatic mammals requires an integrated research and policy approach that, at a minimum, substantially increases the present capacity to monitor their population responses to human impacts, establishes effective enforcement of existing legislation and prevents further impacts from hydropower development. To implement such an approach, information on the ecology of these species is necessary to create public and scientific awareness.

     

Loss of natural coastline influences species diversity of anemonefish and host anemones in the Ryukyu Archipelago

1. Anemonefish and host anemones are distributed in the shallow waters of coral reefs, and thus their existence may be affected by coastal development. The Ryukyu Archipelago includes the Okinawa and Sakishima Islands; the former has experienced extensive land reclamation and drainage in coastal areas while the latter still mostly contains natural coasts. To consider the layout of protected areas needed to conserve diversity of host anemones and anemonefish in the Ryukyu Archipelago, the community structure and coexistence mechanisms of anemones and anemonefish were compared between Okinawa and Sakishima Islands.
2. Six species of anemonefish and seven species of host anemone are distributed in both islands. Among 15 species-pair interactions observed in six species of anemonefish in the Sakishima Islands, 14 were explained by the niche differentiation hypothesis and only one interaction was explained by the cohabitation hypothesis. In the Okinawa Islands, 13 interactions were explained by the niche differentiation hypothesis, one by the cohabitation hypothesis and one by the lottery hypothesis.
3. For both host anemones and anemonefish, β-diversity in the Okinawa Islands was lower and had a more nested structure than that of the Sakishima Islands. β-Diversity and its nestedness did not differ between the two regions excluding study sites adjacent to coastlines, suggesting that differences in the coastal environment affected the diversity of anemones and anemonefish in the Ryukyu Archipelago.
4. These results suggested that there is an urgent need to prioritize the conservation of reef edges, where species diversity is relatively higher than directly next to the terrestrial coastline in Okinawa Island. In the Sakishima Islands, where many natural coasts remain, a wider area from directly next to the coast out to the reef edge needs to be comprehensively protected to increase β-diversity.

     

Ghosts of the coast: global extinction risk and conservation of sawfishes

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Effects of low pH and high temperature on two Palythoa spp. and predator–prey interactions in the subtropical eastern Atlantic

1. In the current context of climate change, benthic cnidarians of the genus Palythoa have been suggested to be resistant owing to their intrinsic biological characteristics. In tropical regions, some species are currently proliferating in areas where environmental conditions are less suitable for other organisms, even replacing hard coral ecosystems.
2. Considering their tropical affinities, phase-shifts towards Palythoa-dominated areas could become more frequent in future climate change scenarios, leading to changes in ecosystem organization. The aim of this study was to evaluate the effect of climate change stressors in two common Palythoa spp. with different habitat affinities within a subtropical region, and the effect upon their predator–prey interactions.
3. The results of this experimental study demonstrated that colonies of P. aff. clavata and P. caribaeorum were significantly affected by exposure to temperature and pH conditions predicted for 2100 in the Canary Islands, during 62 days.
4. Despite zoantharians’ lack of carbonate in their body wall, Palythoa spp. were most affected in their growth rates by lowered pH, and colonies significantly decreased in weight and size. Although all colonies exhibited symptoms of bleaching at high temperature, a reduction in chlorophyll content was also observed at low pH.
5. Predation by Platypodiella picta crabs decreased on P. aff. clavata exposed to acidic conditions, which may compensate for the lowered ecological performance of the species in these climate change conditions. In contrast, P. picta was able to actively feed on P. caribaeorum colonies regardless of the experimental conditions.
6. Despite being suggested as winner species in a climate change scenario, our study demonstrated that low pH negatively impacted Palythoa spp. survival. If the species are not able to acclimatize to the new conditions, changes in their populations may be expected, although their magnitude could be ameliorated by means of a decrease in predation rates.

     

A generic framework to assess the representation and protection of benthic ecosystems in European marine protected areas

1. There is concern across the International Council for the Exploration of the Sea (ICES) region that a consideration of vulnerable components and the wider support mechanisms underpinning benthic marine ecosystems may be lacking from the process of marine protected area (MPA) designation, management and monitoring.
2. In this study, MPAs across six European ecoregions were assessed from a benthic ecology perspective. The study included 102 MPAs, designated by 10 countries, and focused on three aspects regarding the role of the benthos in: (i) the designation of MPAs; (ii) the management measures used in MPAs; and (iii) the monitoring and assessment of MPAs.
3. Qualitative entries to a questionnaire based on an existing framework (EU project ‘Monitoring Evaluation of Spatially Managed Areas’, (MESMA) were collected by 19 benthic experts of the ICES Benthic Ecology Working Group. A pedigree matrix was used to apply a numerical scale (score) to these entries.
4. The results showed clear differences in scores between ecoregions and between criteria. The designation‐phase criteria generally achieved higher scores than the implementation‐phase criteria. Poor designation‐phase scores were generally reiterated in the implementation‐phase scores, such as scores for assessment and monitoring.
5. Over 70% of the MPA case studies were found to consider the benthos to some extent during selection and designation; however, this was not followed up with appropriate management measures and good practice during the implementation phase.
6. Poor spatial and temporal coverage of monitoring and ineffective indicators is unlikely to pick up changes caused by management measures in the MPA. There is concern that without adequate monitoring and adaptive management frameworks, the MPAs will be compromised. Also, there could be an increased likelihood that, with regard to the benthos, they will fail to meet their conservation objectives.
7. This assessment was successful in highlighting issues related to the representation and protection of the benthos in MPAs and where changes need to be made, such as expanding the characterization and monitoring of benthic species or habitats of interest. These issues could be attributable to an ongoing process and/or an indication that some MPAs only have ‘paper protection’.

     

A niche-based gap analysis for the conservation of odonate species in the Brazilian Amazon

1. Despite the current rates of deforestation and the expected climatic changes, protecting species in their natural habitats is still the simplest, cheapest, and most effective way of safeguarding biodiversity. Here, the network of protected areas in the Brazilian Amazon was evaluated to assess its effectiveness in safeguarding species of Odonata.
2. Ecological niche models were built to assess the suitability of the habitat for 503 Amazonian odonate species. Then, the effectiveness for the protection of odonate species of three classes of protected areas (strictly protected area, sustainable use area, and indigenous territory) was evaluated.
3. Approximately 30% of the species are protected within the network of protected areas. These findings highlight the importance of protected areas for safeguarding most odonate species in the Amazon. For under-represented or gap species, additional resources are still needed for effective management and protection on some private properties, which need to set aside land for conservation. In this way, it is possible to preserve habitats for odonate species and guarantee their conservation in the Amazon.