Rocky Reef Communities Research Articles

Assessing the influence of macroalgae and micropredators on the early life success of the echinoid Diademaafricanum

The sea urchin Diadema africanum is an herbivore that has a significant influence on subtidal rocky reef communities on the Canary Islands, facilitating transitions between macroalgal beds and barren grounds. Barren grounds in the archipelago are characterized by a dominance of crustose coralline algae and a lack of invertebrates and fishes compared to macroalgal beds, which are mainly dominated by brown algae. To assess the impact of these benthic community states on the early life success of D. africanum, a manipulative study was conducted in September 2021 at four sites on the eastern coast of Tenerife Island, characterized by the availability of historical settlement rates and adult data for this species. For this purpose, experimental larval collectors modified with a hollow algae-container were employed to examine sea urchin settlement rates in response to two dominant algal species, Lobophora schneideri, in macroalgal beds and crustose coralline algae (CCA) in barren grounds. Statistical analysis revealed significant spatial differences in sea urchin settlement and the interaction between site and treatment response. Specifically, the site with higher sea urchin settlement exhibited lower numbers of D. africanum settlers in treatments containing L. schneideri than in the Control and CCA treatments. Three decapod species (the pistol shrimp Alpheus macrocheles, and the crabs Lophozozimus incisus, and Pachygrapsus marmoratus) negatively correlated with D. africanum settlers. These results suggest that larval supply, L. schneideri beds, and micropredator abundance play a role in the early life success of this species. This may imply a community stability mechanism that helps to prevent shifts between alternative stable states.

Habitat Fragmentation Enhances the Difference between Natural and Artificial Reefs in an Urban Marine Coastal Tract

Coastal urbanization and the consequent proliferation of artificial structures greatly impact rocky reef communities, productive and diverse marine environments that play a crucial role in the functioning of broader coastal ecosystems. This study, conducted along a 7 km stretch of coastline at increasing distance from the port of Genoa (Ligurian Sea), investigated whether the alternating presence of artificial and natural reefs leads to discernible differences in the biota inhabiting these two reef types. The study area is one of the most anthropized areas of the Mediterranean Sea, exhibiting nearly 60% coastal artificialization, which severely impacts coastal ecosystems, favouring the replacement of sensitive species with more tolerant species. Ten reefs (5 natural and 5 artificial) were surveyed by scuba diving at about a 6-m depth, employing quadrats of 50 cm × 50 cm to estimate visually the percent cover of conspicuous sessile organisms. The artificial reefs hosted a similar number of species (18) to their natural counterparts (19) but exhibited a distinct community composition: the former were especially characterized by Jania rubens and filamentous algae, with the latter characterized by Peyssonnelia squamaria and Mesophyllum lichenoides. This difference, however, became negligible where coastal habitat fragmentation (here measured with a purposely devised Fragmentation Index) was minimal. Reducing fragmentation may therefore represent a management strategy to minimize the potential impact of artificial structures on marine biodiversity.

Assessment of macroalgal communities on shallow rocky reefs in the Aegean Sea indicates an impoverished ecological status

Mediterranean rocky reefs are undergoing regime shifts, from a structurally complex and diverse state dominated by canopy- forming macroalgae to a degraded one characterised by low-lying turf or encrusting macroalgal species, due to increased anthropogenic pressure and climate change. Using data gathered from 89 sites across the entire Aegean Sea, this study aims to provide the most comprehensive health status assessment of shallow rocky reefs in the area, based on macroalgal community structure. Overall, 2520 benthic images were collected through photoquadrat sampling at 0, 5 and, 15 m depth. Five macroalgal and seven invertebrate morphofunctional groups, along with four substrate categories, were considered for community structure description. Health status was assessed using the reef-EBQI and EEI-c indices. Results indicate turf as the most widespread macroalgal group (36.8% average area cover), followed by encrusting calcareous (16.6%), shrubby (12.7%), articulated calcareous (8.9%), and canopy-forming algae (3.7%). Bare rock also occupied a substantial surface area (9.0%) with highest cover (13.8%) at 5 m. The area cover of canopy-forming algae was particularly low, ranging from 10% at 0 m to 0.1% at 15 m depth, on average. All depths pooled, according to the reef-EBQI index, the ecological status of the Aegean Sea was estimated to be ‘Bad’, mainly due to the bad ecological status of the 5 and 15 m stations. At 0 m depth, the status of the Aegean Sea was ranked ‘Moderate’ according to the reef-EBQI index and ‘Good’ according to the EEI-c index. The results underline the importance of considering a wide depth range when assessing the health status of rocky reef communities.

Benthic source dominance in temperate rocky reefs revealed by stable isotopes

Rocky reefs are heavily impacted by anthropogenic activity and since they are important breeding, nursery and feeding areas, their protection is imperative. To improve conservation methods, it is necessary to understand the structure and processes of rocky reef communities. Trophic relationships are one of the examples of species connection, with food webs representing the flow of matter and energy from producers to consumers and from prey to predators. Stable isotope analysis (δ13C and δ15N) was used to characterize the food web of the rocky reefs of Arrábida Marine Protected Area (Portugal) and to explore habitat complexity – niche diversification relationships. Results showed a complex food web with high trophic richness supported by a wide range of basal resources. As a result of the wide range of basal resources and primary consumers the food web was characterized by a high degree of omnivory which led to a relatively short food web. Furthermore, consumers displayed diverse diets and feeding strategies, exploiting different sources of organic matter, of both benthic (macroalgae and benthic POM) and pelagic origin (phytoplankton and pelagic POM). However, the benthic pathway was more important with more than half of the diet of most secondary and tertiary consumers following this route, hinting at the importance held by macroalgae and benthic production in this ecosystem. Overall, the high habitat complexity allied to the shallow and sheltered location of the reefs increased niche diversification (wide range of basal resources) supporting a diversity of omnivore species which improved the connectance among taxa and thus the complexity of the food web. This study is an essential step to better understand shallow temperate rocky reefs and, as such, provide additional support for conservation measures and management decisions.

Troubles Never Come Alone: Outcome of Multiple Pressures on a Temperate Rocky Reef

Climate change is affecting rocky reef ecosystems in a multitude of ways at global scale. During summer 2018, the rocky reef communities of Portofino Marine Protected Area (MPA) (NW Mediterranean) were affected by thermal anomalies, a mucilaginous event, and the seasonal expansion of Caulerpa cylindracea. Moreover, a severe storm occurred on 29 October. The effects of these pressures on the rocky reef communities were analysed at different depths (10 m, 20 m, 30 m, and 40 m) and at three times (June, October, December) to evaluate change at short temporal scale. Portofino MPA’s communities have significantly changed: thermal anomalies mostly affected the biota living above the summer thermocline (ca 20 m depth); mucilaginoius aggregates first impacted the communities in shallow waters and only later those in deep waters, where they typically fall in late summer; the greatest impact by Caulerpa cylindracea was detected at 20 m depth; the storm directly impacted communities in shallow and intermediate waters by uprooting algal species, while it had indirect effects at greater depths through sediment redistribution. Disentangling the effects of multiple pressures on coastal ecosystems is one of the most pressing goals in marine ecology and biodiversity conservation. This study represents an attempt in this direction as applied to the short-term dynamics of rocky reef communities under a climate change scenario.

Tropicalization shifts herbivore pressure from seagrass to rocky reef communities.

Climate-driven species redistributions are reshuffling the composition of marine ecosystems. How these changes alter ecosystem functions, however, remains poorly understood. Here we examine how impacts of herbivory change across a gradient of tropicalization in the Mediterranean Sea, which includes a steep climatic gradient and marked changes in plant nutritional quality and fish herbivore composition. We quantified individual feeding rates and behaviour of 755 fishes of the native Sarpa salpa, and non-native Siganus rivulatus and Siganus luridus. We measured herbivore and benthic assemblage composition across 20 sites along the gradient, spanning 30° of longitude and 8° of latitude. We coupled patterns in behaviour and composition with temperature measurements and nutrient concentrations to assess changes in herbivory under tropicalization. We found a transition in ecological impacts by fish herbivory across the Mediterranean from a predominance of seagrass herbivory in the west to a dominance of macroalgal herbivory in the east. Underlying this shift were changes in both individual feeding behaviour (i.e. food choice) and fish assemblage composition. The shift in feeding selectivity was consistent among temperate and warm-affiliated herbivores. Our findings suggest herbivory can contribute to the increased vulnerability of seaweed communities and reduced vulnerability of seagrass meadows in tropicalized ecosystems.

Rebirth of a reef: As-built description and rapid returns from the Palos Verdes Reef Restoration Project

Palos Verdes Reef (PVR) is an artificial reef designed to restore rocky-reef associated marine species by directly restoring rocky-reef habitat that has been impacted by scour, sedimentation, and burial in the shallow subtidal portion of the Palos Verdes Peninsula in Los Angeles County, California, USA. The restoration reef provides high-quality habitat that is contiguous with the natural reef and allows for rapid succession. This project is a unique endeavor as restoring lost habitat in situ and has not been attempted in a temperate rocky reef and kelp forest community. While the primary design criteria for PVR is fish production in an area where already-limited hard substrate had been lost, it is also designed to be resilient to ongoing sedimentation and turbidity challenges on the peninsula. Following over a decade of design, planning, outreach, site surveying, and permitting, PVR was built in 2020 as 18 discrete modules using 52,729 tons of quarry rock placed approximately 8–80 m from existing, unburied rocky-reef habitat. There was no significant accumulation or scouring of sediment due to the placement of the reef and temperature data shows that internal tides regularly inundate the reef with cool, nutrient rich water. Rocky-reef associated taxa rapidly recruited to the restoration site, with visible changes occurring within just a few months post-construction. PVR modules showed rapid, significantly positive responses in fish density, fish biomass, kelp density, and biotic benthic cover less than 18 months after reef placement with a general pattern of succession in giant kelp growth from nearshore to offshore resulting in an established, thick canopy, in the nearshore, shallow modules. The newly available, high-quality habitat was quickly colonized and already shows late successional patterns with respect to fish and benthic communities. This restoration reef will produce large amounts of biomass over the long-term, though future surveys of multiple restored, adjacent, and reference sites will determine if high biomass at PVR is a result of new secondary production or attraction from nearby reefs.

Variability between observers does not hamper detecting change over time in a temperate reef

Marine ecosystems are subject to global and local impacts, both contributing to dramatic changes in coastal communities. Assessing such changes requires time series or the revisitation of sites first surveyed in the past. In both cases, data are not necessarily collected by the same observers, which could lead to a bias in the results. In the Marine Protected Area (MPA) of Capo Carbonara (Sardinia, Italy), established in 1998, rocky reef communities were first assessed in 2000 by two diving scientists. Twenty years later, the same rocky reefs were resurveyed using the same method by two other diving scientists. In both surveys, semi-quantitative data on conspicuous species were collected at five sites in four depth zones, providing the possibility of assessing change over time. To explore the influence of climate and local pressures, existing data on sea surface temperature, resident population, tourism and diving activities were analysed. The reef communities of the Capo Carbonara MPA have distinctly changed over time, mostly under the effect of seawater warming, as highlighted by the occurrence of thermophilic species and by other climate-related indicators. On the other side, species vulnerable to local human pressures have increased over time, demonstrating the effectiveness of the protection measures undertaken by the MPA. Comparing data collected by four different observers in the two periods demonstrated that change over time was significantly greater than variability between the observers.

Organic contaminants in imported salmon feed and their effects on reef ecosystems in New Zealand

Organic matter from salmon farms has been shown to be assimilated by soft sediment and rocky reef communities within the ecological footprint of salmon farms. Given these findings, another question arises – What other chemicals in salmon feed may be assimilated into wild communities via organic waste from salmon farms? Here we measured a suite of organic contaminants in salmon feed, in organisms used in a controlled feeding experiment, and in reef species collected within the depositional footprint of salmon farms. Gas Chromatography-Tandem Mass Spectrometry was used to quantify trace concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and current-use (CPUs) and historic-use pesticides (HUPs) in salmon feed imported to New Zealand. The effect of assimilation of farm-derived organic matter on contaminant profiles differed among species during the controlled feeding experiment and demonstrated that migration of individuals to a farm-associated site has the potential to increase or decrease organic contaminant concentrations. Concentrations of PCBs in Parapercis colias (blue cod), a highly resident, long-lived fish, were significantly higher at farm sites than at reference sites. While these concentrations were relatively low in a global context, this result presents blue cod as an important candidate for future monitoring of organic contaminants around point sources. PCBs and PBDEs measured in wild marine species were all below limits set by the European Union, whereas concentrations of certain HUPs, specifically dichlorodiphenyltrichloroethane (DDT) and its degradation products and endosulfan, may be of concern as a consequence of alternative anthropogenic activities. Overall, feed imported to New Zealand had relatively low levels of most organic contaminants that, at current levels, are unlikely to result in significant ecological effects to wild communities in adjacent habitats.

Shipwrecks fouling community: Similarities with natural rocky reefs at different distances and wave exposure regimes

Artificial reefs, such as shipwrecks, have been considered as an alternative to mitigate impacts on natural hard bottoms. On the other hand, unplanned artificial reefs can lead to several negative effects such as the introduction of toxic substances, further propagation of exotic and pathogen species, and impacts on the surrounding soft bottom habitat through alteration of bottom topography and dynamics. Artificial reefs are colonized by different organisms, exchanging larvae and spores with the nearest natural reefs, however, few studies have focused on the understanding of the benthic communities’ structures found on these coupling natural and artificial reefs. The aim of this study was to investigate whether benthic communities of centenary shipwrecks can be similar to natural rocky reef communities established at a short scale distance. The benthic cover of shipwrecks sunken more than 100 years ago and that of natural reefs located at a gradient distance of 0, 1 and 2 km, and differently exposed to wave action, were compared. Using multivariate analyses, we found that similarities were influenced by both wave exposure and distance. In exposed area, the benthic fouling community in shipwreck was similar to the benthic communities of the nearest reefs, with decreasing values of richness with distance. Sheltered area communities presented high dissimilarity. Once the presence of an artificial reef influences benthic communities of natural ones, we recommend the evaluation of the cost/benefits of introducing artificial reefs, considering local hydrodynamics and proximity to natural environments, to minimize undesirable changes in natural environment.

How Do Biological and Functional Diversity Change in Invaded Tropical Marine Rocky Reef Communities?

Evidence so far shows that most alien species (AS) have negative impacts on native biodiversity and are changing biodiversity in almost all environments. Here, we study eight rocky shores at four sites containing reefs with invaded communities and other not-invaded (control) communities, to evaluate the effects of four marine invasive species on biological and functional diversity. We used the adjustment and selection approach of species abundance distribution models (SAD), taxonomic diversity indices and functional diversity indices based on hierarchical grouping matrices (FD—Functional Diversity). In addition to comparing invaded and not-invaded communities, we also performed the same analysis, but removed the invaders (AS removed) from the matrices. The geometric-series model was best adjusted to the majority of communities. The diversity indices suggest that the taxonomic diversity is lower in invaded communities, while the functional diversity indices suggest a change in the functional space of invaded and not-invaded communities, with a greater amount of functional space filled by species in the not-invaded communities. Taxonomic and functional diversity indices were successful in identifying processes that determine the biological diversity of invaded communities, as they seem to obey a pattern that reflects the reduced diversity of invaded communities.

Transient dynamics during kelp forest recovery from fishing across multiple trophic levels.

Outcomes of management efforts to recover or restore populations of harvested species can be highly dependent on environmental and community context. Predator-prey interactions can alter recovery trajectories, and the timing of management actions within multi-trophic level harvest scenarios may influence the dynamics of recovery and lead to management trade-offs. Recent work using a generalist predator-prey model suggests that management promoting synchronized recovery of predators and prey leads to faster and less variable recovery trajectories than sequential recovery (predator or prey first). However, more complex communities may require different management actions to minimize recovery time and variability. Here, we use a tri-trophic level rocky reef community dynamics model with size-structure and fisheries at multiple trophic levels to investigate the importance of three ecological processes to recovery of fished communities: (1) size-structured predation, (2) non-consumptive effects of predators on prey behavior, and (3) varying levels of recruitment. We also test the effects of initiating recovery from community states associated with varying degrees of fishery-induced degradation and develop a simulation in which the basal resource (kelp) is harvested. In this system, a predator-first closure generally leads to the least volatile and quickest recovery, whether from a kelp forest, urchin barren, or intermediate community state. The benefits gained by selecting this strategy are magnified when recovering from the degraded community, the urchin barren, because initial conditions in the degraded state lead to lengthy recovery times. However, the shape of the size-structured predation relationship can strongly affect recovery volatility, where the differences between alternate management strategies are negated with size-independent predation. External recruitment reduces return times by bolstering the predatory lobster population. These results show that in a tightly linked tri-trophic level food web with top-down control, a predator-first fishery closure can be the most effective strategy to reduce volatility and shorten recovery, particularly when the system is starting from the degraded community state. Given the ubiquity of top predator loss across many ecosystems, we highlight the value of incorporating insights from community ecology into ecosystem management.

Monitoring rocky reef biodiversity by underwater geo-referenced photoquadrats

Digital images are an excellent tool for divers to sample hard-bottom subtidal habitats as bottom time is limited and high-definition images can be collected quickly and accurately. The present paper describes a sampling protocol for benthic rocky reef communities using geo-referenced photoquadrats and tests the method over several rocky reefs of Atlantic Patagonia. This method was tested in two localities, separated by 100 km in a semi-enclosed gulf, covering a total of 5800 m of 11 rocky reefs using track roaming transects. The protocol is non-destructive, relatively low-cost and can adequately assess changes in marine habitats as rocky reefs. The implementation of artificial intelligence analysis using human expert training may reduce analysis time and increase the amount of data collected. The present study recommends this sampling methodology for programs aimed at monitoring changes in biodiversity.

Upgrades of coastal protective infrastructure affect benthic communities

Abstract Sea‐level rise, storm surges, ageing and wear are forcing upgrades to breakwaters and sea walls to protect coastal areas from erosion and inundation. Such upgrades involve the introduction of new material which may consequently act as an ecological disturbance that can alter established marine communities and ecosystem function. Mitigating ecological impacts requires an understanding of how species assemblages are affected by such works. Here, we use the major upgrade of a regularly wave‐overtopped breakwater as a case study to evaluate the impacts of upgrades to hard coastal protective infrastructure on benthic rocky reef communities. An asymmetrical Before‐After Control‐Impact (BACI) experimental design was used to test interactive effects of the infrastructure upgrades on benthic communities. While benthic assemblages were not significantly different from controls prior to the upgrade, improving the defensive capacity of the breakwater significantly changed community structure. Notably, most taxonomic groups showed higher cover at the control sites than at the impacted site post‐upgrade, with articulated calcareous algae (e.g. Corallina officinalis and Amphiroa anceps) showing an opposite trend. Synthesis and applications. Ecological implications and structural limitations make regular upgrading of existing infrastructure unsuitable as a long‐term management strategy. More sustainable alternatives need to be considered, such as decommissioning of structures and retreat from flood‐prone areas. This transition, however, will take time and requires a change of mindset and policies. Where upgrades are urgent, eco‐engineering techniques can mitigate impacts to habitats and associated taxa.

Nuevo registro de Mendosoma lineatum Guichenot, 1848 en Patagonia central, Argentina, con comentarios sobre la comunidad de peces de arrecife

Se ha realizado un nuevo registro de Mendosoma lineatum en aguas centrales de la Patagonia. Este registro es la segunda mención después de que un espécimen fue capturado en el norte del Golfo San Jorge en 2012. Se propuso que el espécimen llegó de la Corriente Circumpolar Antártica y esta hipótesis ahora se refuerza con este nuevo registro. El número de especies que componen la comunidad de arrecifes rocosos de la Patagonia central también se extiende aquí. En la actualidad, ocho especies han sido reconocidas como parte de este entorno, y en este documento el número se extiende a quince con siete nuevas especies identificadas.

Sea urchin control of macroalgal communities across a productivity gradient

Opposing bottom-up ‘resource-driven’ and top-down ‘consumer-driven’ forces interact to shape the structure of ecosystems. While these counteracting forces are well recognised, debate remains regarding which is more influential across space and time. Here we explore bottom-up versus top-down control of macroalgal communities for temperate rocky reef communities in highly urbanised Port Phillip Bay (PPB), southeast Australia. Field surveys show macroalgal cover to paradoxically decline with increasing ‘bottom-up’ nutrient inputs while the abundance of grazing sea urchins (Heliocidaris erythrogramma) increased. The mechanisms underpinning this pattern were examined by constructing urchin-exclusion plots using octocoral (Erythropodium hicksoni) colonies that grow on urchin barren grounds and form natural barriers to grazing sea urchins. Octocoral plots were constructed by cutting 200 mm by 200 mm squares to expose bare reef substratum within the centre of octocoral colonies, which enabled efficient replication of urchin-exclusions on barren grounds across three distinct zones of anthropogenic nutrient input in PPB. Octocoral plots successfully excluded urchins across zones and, in the absence of grazing, macroalgal production increased with increasing nutrient concentration as expected. This novel opportunity to efficiently replicate urchin-exclusions on high-density barren grounds across different zones of ‘bottom-up’ forcing demonstrates that urchin overgrazing can keep pace with and overwhelm increasing macroalgal productivity. Our findings also highlight that impacts of grazing can be greatest where bottom-up forces enable large abundances of herbivores to accumulate, which is counter to perceptions that impacts of herbivores will be greatest where macroalgal productivity is low.

At what spatial scales are alternative stable states relevant in highly interconnected ecosystems?

Whether ecosystems recover from disturbance depends on the presence of alternative stable states, which are theoretically possible in simple models of many systems. However, definitive empirical evidence for this phenomenon remains limited to demographically closed ecosystems such as lakes. In more interconnected systems such as temperate rocky reefs, the local relevance of alternative stable states might erode as immigration overwhelms local feedbacks and produces a single stable state. At larger spatial scales, dispersal might counter localized disturbance and feedbacks to synchronize states throughout a region. Here, we quantify how interconnectedness affects the relevance of alternative stable states using dynamical models of California rocky reef communities that incorporate observed environmental stochasticity and feedback loops in kelp-urchin-predator interactions. Our models demonstrate the potential for localized alternative states despite high interconnectedness likely due to feedbacks affecting dispersers as they settle into local communities. Regionally, such feedbacks affecting settlement can produce a mosaic of alternative stable states that span local (10-20km) scales despite the synchronizing effect of long-distance dispersal. The specific spatial scale and duration of each state predominantly depend on the scales of environmental variation and on local dynamics (here, fishing). Model predictions reflect observed scales of community states in California rocky reefs and suggest how alternative states co-occur in the wide array of marine and terrestrial systems with settlement feedbacks.

Abrupt Change in a Subtidal Rocky Reef Community Coincided with a Rapid Acceleration of Sea Water Warming

Seawater warming is impacting marine ecosystems, but proper evaluation of change requires the availability of long-term biological data series. Mesco Reef (Ligurian Sea, Italy) offers one of the longest Mediterranean data series on sessile epibenthic communities, based on underwater photographic surveys. Photographs taken in four stations between 20 m and 40 m depth allowed calculating the percent cover of conspicuous species in 1961, 1990, 1996, 2008, and 2017. Multivariate analysis evidenced an abrupt compositional change between 1990 and 1996. A parallel change was observed in Ligurian Sea temperatures. Two invasive macroalgae (Caulerpa cylindracea and Womersleyella setacea) became dominant after 1996. Community diversity was low in 1961 to 1996, rapidly increased between 1996 and 2008, and exhibited distinctly higher values in 2008–2017. A novel community emerged from the climate shift of the 1990s, with many once characteristic species lost, reduced complexity, biotic homogenization, greater diversity and domination by aliens. Only continued monitoring will help envisage the possibility for a reversal of the present phase shift or for further transformations driven by global change.

An Alien Invader is the Cause of Homogenization in the Recipient Ecosystem: A Simulation-Like Approach

Biotic homogenization is an expected effect of biological invasions. Invasive alien species typically show great adaptability to a wide range of environmental conditions and may expand into different habitats, thus reducing the dissimilarity among the recipient communities. We tested this assumption by analyzing a comprehensive database (78 species × 229 samples) collected between 2012 and 2017 in the marine protected area of Portofino (NW Italy), where Caulerpa cylindracea, one of the worst invaders in the Mediterranean Sea, exhibits high substratum cover at depths between 1 m and 45 m in 14 different communities (identified according to the European Nature Information System EUNIS for habitat classification). Five samples for each of the eight depth zones (i.e., 5 m, 10 m, 15 m, 20 m, 25 m, 30 m, 35 m, and 40 m) were randomly re-sampled from the comprehensive database to produce a dataset of 67 species × 40 samples. Then, a second dataset of 66 species × 40 samples was simulated by excluding Caulerpa cylindracea. Both re-sampled datasets underwent multivariate analysis. In the presence of C. cylindracea, the overall similarity among samples was higher, thus indicating homogenization of the rocky reef communities of Portofino Marine Protected Area. Continued monitoring activity is needed to understand and assess the pattern and extent of C. cylindracea’s inclusion in the recipient ecosystems.

Empirical Validation of an Ecosystem Service Map Developed From Ecological Principles and Biophysical Parameters

Mapping ecosystem services in marine systems is difficult due to a lack of underpinning ecological data. The Ecological Principles Approach (EPA) was developed to link simple summary statements on how ecosystems function to ecosystem services and was further advanced into a mapping technique by aligning and weighting commonly available spatial datasets to generate maps of specific services. The objective of the present investigation was to validate a predicted map of biogenic habitat provision with empirical ground-truthed data. A survey was undertaken to assess the biogenic habitat structure at 56 sites in the Hauraki Gulf, New Zealand. Information on benthic biogenic structure was ranked from 1-5 relating to a combination of height and complexity. Rank groups were assessed for differences in predicted levels of service and the accuracy of supporting data. We found high agreement between the empirical observations and the model predictions: in areas predicted by the approach to have the highest levels of biogenic habitat complexity the habitat was typified by complex rocky reef communities and macroalgal forests. We showed that ecosystem services can be accurately mapped in marine systems at low cost and with modest data requirements, which further enhances the utility of this approach.