Seawater-atmosphere O(2) exchange rates in open-top laboratory microcosms: application for continuous estimates of planktonic primary production and respiration

Foraging by predatory fish is thought to be one of the primary ecological processes affecting the abundances of plants and animals in subtidal habitats. The importance of this process was assessed on the subtidal surfaces of urban structures (pontoons and pilings) that represent major coastal habitats for marine organisms. Fish feed with greater intensity on epibiota attached to pilings than pontoons and it was hypothesised that greater predation on pilings explained why the structure of epibiotic assemblages differs between these habitats. I predicted that the structure of epibiotic assemblages would develop differently between pilings and pontoons in the presence of fish (plates open to predation) but not in the absence of fish (plates inside exclusion cages). Results revealed large differences in abundance between pilings and pontoons that were largely independent of the caged and uncaged plates. Predation may be intense (as it appeared on pilings) but unimportant because it does not explain observed abundances of prey (epibiota between pilings and pontoons).     

Surface composition and orientation interact to affect subtidal epibiota

Settlement panels were used to evaluate the effects of composition of the substratum (sandstone, concrete, wood) and orientation (vertical, horizontal undersides) on subtidal epibiota. It was predicted that both factors would influence the development of epibiotic assemblages, but that differences due to composition would be less marked on horizontal undersides compared to vertical panels. Differences in assemblages among sandstone, concrete and wooden panels orientated vertically were predicted to be similar to those described previously among vertical surfaces of sandstone rocky reefs and concrete and wooden urban structures (pilings and pontoons). Multivariate analyses indicated that assemblages were influenced greatly by orientation, whereas the effects of surface composition differed for the two orientations and among sites. Assemblages on wood were always significantly different from those on sandstone or concrete - patterns between the latter two surfaces depended on the orientation of the panels. The taxa that dominated these surfaces were not similar in identity nor abundance to those on urban structures of the same composition. The covers of most taxa were influenced by orientation alone or by surface composition for just one orientation. This study demonstrates the need for caution in generalizing about effects of orientation and surface composition because they may interact with each other and/or with other factors and they are certainly quite different for different taxa and among sites.     

Mussel beds on different types of structures support different macroinvertebrate assemblages

Abstract Artificial structures, such as seawalls, pilings and pontoons, are common features of urban estuaries. They replace natural structures or add to the amount of hard substratum in an area and provide habitats for many fish and invertebrates. Previous work has concentrated on fish or on the invertebrates that occupy the primary substratum of artificial structures. Mussels often grow on different types of structures (pontoons, pilings, seawalls and natural reefs) and provide a secondary substratum for other organisms to inhabit. Counting and identifying organisms associated with mussel beds is traditionally done to species level, which is very time‐consuming. To save time, organisms in this study were identified to coarse levels of taxonomic resolution (a mix of taxa, such as class, order, family and genus), which showed similar patterns to those when particularly speciose and abundant groups were identified to species. This study tests hypotheses that the distribution and abundance of mobile and sessile organisms that inhabit mussel beds will differ among natural and various types of artificial structures. When the associated assemblages of mussel beds from different types of structures and from different locations were examined, assemblages varied according to the type of structure they inhabited and its location. Assemblages associated with mussels on pontoons differed consistently from those on other types of structures. Patterns in the assemblages were also consistent through time. These data show that the types and amounts of artificial structures added to an environment can affect the types, distribution and abundances of organisms living in biogenic habitats.     

Fish assemblages associated with urban structures and natural reefs in Sydney,Australia

Abstract Fish ecology in urban estuaries is poorly understood. As coastal landscapes are transformed, recognizing the impact that urban structures, such as marinas, seawalls and wharfs, have on local fish populations is becoming increasingly important. The extent to which fish are able to maintain natural ecological assemblages can be measured, to a certain extent, by how closely they mimic natural habitats. In Sydney Harbour, assemblages of fish associated with artificial structures were compared with those associated with natural rocky reefs. Sampling was carried out in five locations, each with a marina, swimming enclosure and natural reef. In each location, different habitats supported different assemblages, but differences between habitats were not consistent among locations. Subsequent sampling compared artificial and natural sites in three different areas in each of three different estuaries. Results indicated that differences in fish assemblages between artificial and natural sites were greater than differences between sites within each habitat, but there were no patterns among different positions in an estuary or from estuary to estuary. This study provides initial evidence that, although artificial habitats generally support the same species as found on natural reefs, assemblages usually differed between natural and artificial habitats. In addition, without knowing if these habitats do, in fact, sustain viable populations of fish, it would be premature to label artificial structures as effective habitat for fish.     

Artificial structures influence fouling on habitat-forming kelps

The addition of artificial structures along urbanised shorelines is a global phenomenon. Such modifications of habitats have important consequences to the abundance of fouling organisms on primary substrata, but the influence on fouling of habitat-formers living on these structures is poorly understood. Fouling of habitat-forming kelps Ecklonia radiata on pier-pilings was compared to that on rocky reefs at three locations in Sydney Harbour. Kelps on pilings supported different assemblages of bryozoans from those on reefs. The abundances of bryozoans on kelps, in particular of the non-indigenous species Membranipora membranacea, were significantly greater on pilings. Differences were consistent in time and space. This indicates that the addition of artificial structures also affects fouling on secondary biogenic substrata, altering biodiversity and potentially facilitating the introduction and dispersal of non-indigenous epibiota. Understanding the processes that cause these patterns is necessary to allow sensible predictions about ecological effects of built structures.     

Artificial structures influence fouling on habitat-forming kelps

The addition of artificial structures along urbanised shorelines is a global phenomenon. Such modifications of habitats have important consequences to the abundance of fouling organisms on primary substrata, but the influence on fouling of habitat-formers living on these structures is poorly understood. Fouling of habitat-forming kelps Ecklonia radiata on pier-pilings was compared to that on rocky reefs at three locations in Sydney Harbour. Kelps on pilings supported different assemblages of bryozoans from those on reefs. The abundances of bryozoans on kelps, inparticular of the non-indigenous species Membranipora membranacea, were significantly greater on pilings. Differences were consistent in time and space. This indicates that the addition of artificial structures also affects fouling on secondary biogenic substrata, altering biodiversity and potentially facilitating the introduction and dispersal of non-indigenous epibiota. Understanding the processes that cause these patterns is necessary to allow sensible predictions about ecological effects of built structures.     

Marine dock pilings foster diverse,native cryptobenthic fish assemblages across bioregions

Anthropogenic habitats are increasingly prevalent in coastal marine environments. Previous research on sessile epifauna suggests that artificial habitats act as a refuge for nonindigenous species, which results in highly homogenous communities across locations. However, vertebrate assemblages that live in association with artificial habitats are poorly understood. Here, we quantify the biodiversity of small, cryptic (henceforth “cryptobenthic”) fishes from marine dock pilings across six locations over 35° of latitude from Maine to Panama. We also compare assemblages from dock pilings to natural habitats in the two southernmost locations (Panama and Belize). Our results suggest that the biodiversity patterns of cryptobenthic fishes from dock pilings follow a Latitudinal Diversity Gradient (LDG), with average local and regional diversity declining sharply with increasing latitude. Furthermore, a strong correlation between community composition and spatial distance suggests distinct regional assemblages of cryptobenthic fishes. Cryptobenthic fish assemblages from dock pilings in Belize and Panama were less diverse and had lower densities than nearby reef habitats. However, dock pilings harbored almost exclusively native species, including two species of conservation concern absent from nearby natural habitats. Our results suggest that, in contrast to sessile epifaunal assemblages on artificial substrates, artificial marine habitats can harbor diverse, regionally characteristic assemblages of vertebrates that follow macroecological patterns that are well documented for natural habitats. We therefore posit that, although dock pilings cannot function as a replacement for natural habitats, dock pilings may provide cost‐effective means to preserve native vertebrate biodiversity, and provide a habitat that can be relatively easily monitored to track the status and trends of fish biodiversity in highly urbanized coastal marine environments.     

Benthic assemblages,biodiversity and invasiveness in marinas and commercial harbours: an investigation using a bioindicator group

Fouling communities on artificial marine structures are generally different from benthic communities in natural rocky habitats. However, they may also differ among different types of artificial structures. Two artificial structures in direct contact with arriving vessels were compared: floating pontoons within recreational marinas, and sea-walls within commercial harbours. Natural rocky habitats were used as a reference, and the genus Eudendrium (Cnidaria, Hydrozoa) was chosen as a bioindicator. The assemblages were different among the three types of habitat studied, with different species characterising each habitat. The probability of finding an invasive Eudendrium species was significantly higher on pontoons. Diversity was the lowest on pontoons, but it was not significantly different between sea-walls and natural rocks. In general, a barrier to the spread of exotic species exists between harbours and natural rocky habitats. Floating pontoons seem to be a less suitable habitat for native fauna and a key element in marine biological invasions.     

Weak Effects of Epibiota on the Abundances of Fishes Associated with Pier Pilings in Sydney Harbour

Biogenic habitats have profound effects on the distribution and abundances of many organisms. Epibiota are major biogenic components of hard substrata in marine habitats, particularly on artificial structures such as pier pilings, and have the potential to influence organisms associated with these structures. This study tested hypotheses about effects of epibiota on abundances of fishes associated with pilings in Middle Harbour, Sydney. Amount of epibiota had no effect on abundances of most species of fish, suggesting that epibiota are not important resources for these species. Abundances of the hulafish, Trachinops taeniatus, were, however, found to be greater around pilings with large than pilings with small amounts of epibiota at one site, at each of two times. Experimental removals of epibiota from pilings were done to test the hypothesis that epibiota are an important resource to T. taeniatus. Despite great temporal fluctuations in abundances over the duration of the experiment, the response of T. taeniatus to the removal of epibiota from pilings was as predicted, falling to zero following removal of epibiota. Although this suggests that epibiota are an important resource for this species, this pattern was spatially and temporally variable. We suggest that variation in the amount of epibiota has minor effects on the abundances of fishes around pilings.     

Changes in rocky reef fish assemblages throughout an estuary with a restricted inlet

Rocky reef habitat is common in many estuaries, yet its role as a habitat for fishes is poorly understood. There is also limited understanding of how access of coastal species into estuaries and habitat quality can affect the distribution of rocky reef fishes within estuaries. This study used baited remote underwater video stations to determine spatial patterns in fish assemblages associated with rocky reef habitat throughout a barrier estuary with a permanently open but restricted inlet. Estuarine rocky reefs provided habitat for a diverse assemblage of fishes, many of which were large juveniles and subadults. In the absence of a pronounced salinity or temperature gradient, a clear transition in fish assemblages occurred from coastal waters, through the inlet channel, to the central estuary, and into the inner estuary. The inlet channel, notably its narrowness and length, limits tidal input into this estuary, which acts as a significant impediment to the dispersal of many coastal fishes, and insufficient habitat excludes many coastal rocky reef species from the inner estuary. This study highlights the need to recognise estuarine rocky reefs as providing habitat for diverse fish assemblages and the role inlets play in restricting access of coastal species.     

The Colonisation of Human-made Structures by the Invasive Alga Codium fragile ssp. tomentosoides in the North Adriatic Sea (NE Mediterranean)

Human-made structures, such as groynes, breakwaters, seawalls, pier pilings and floating pontoons, are becoming common features of the landscape in urbanised coastal and estuarine areas. Despite this tendency few studies have focused on their ecology or on their potential impacts on natural assemblages of organisms. When artificial structures are introduced in areas with little or no hard substrata, they not only provide novel habitats, which enables the colonisation of sandy areas by hard-bottom dwelling species, but they can also provide suitable habitats for exotic species. Along the north-east coast of Italy, sandy shores are protected from erosion by a line of breakwaters, which runs almost uninterrupted for about 300 km. These structures provide habitat for a variety of macroalgae and invertebrates and also for the invasive green alga Codium fragile ssp. tomentosoides. The aim of this study was, therefore, to investigate patterns of distribution of this alga on breakwaters in Cesenatico. In particular, we compared the density of thalli, biomass, length and degree of branching of C. fragile ssp. tomentosoides between the landward and the seaward sides of breakwaters, to test the hypothesis that sheltered habitats (landward) represent more suitable habitats than exposed habitats (seaward). In general, the landward side of breakwaters supported greater numbers of thalli of C. fragile ssp. tomentosoides than seaward sides. Thalli grew longer and more branched in sheltered habitats, leading to an overall larger biomass of the alga on the landward side of breakwaters. The presence of sheltered human-made hard substrata in the vicinity of major trading ports and sources of eutrophication could enhance the dispersal of invasive species across regional and geographic scales. Thus, the effects of artificial structures and introduced species on coastal assemblages cannot be evaluated separately, but their synergistic nature should be considered in planning strategies for conservation of biodiversity in coastal habitats.     

Intertidal assemblages on seawalls and vertical rocky shores in Sydney Harbour,Australia

Abstract Understanding the ecological role of artificial structures, such as seawalls, in shallow coastal waters is necessary in order to plan sound strategies of conservation and management of natural habitats. In Sydney Harbour (NSW, Australia), about 50% of the foreshore is made of retaining seawalls This study evaluates the changes caused to natural assemblages of organisms by these structures, by comparing intertidal assemblages between seawalls and vertical rocky shores. The following hypotheses were tested: that assemblages on seawalls would differ from those on rocky shores at mid‐, but not at low‐shore levels; where assemblages differ between habitats, there would be differences in cover/abundances of widespread species; patterns would be consistent among locations and through time; the variability of assemblages at the scales of 10s of cm and metres would differ between seawalls and rocky shores at mid‐ and low‐shore levels. To test these hypotheses, assemblages on seawalls and rocky shores were sampled at three locations, at roughly 4‐monthly intervals, over a period of about 18 months. Results indicated that mid‐shore assemblages on seawalls were different from those on rocky shores, but this was not the case at low‐shore levels. Few taxa were unique to either habitat. Cover of common species of algae and sessile animals and abundances of mobile grazers were variable with few consistent patterns. Variability at the scales sampled differed between habitats and heights on the shore. Seawalls and rocky shores, in general, supported a similar suite of species, but patterns of abundance and variation differed among locations and from height to height in each habitat. The implications of these findings for the future management of seawalls are briefly considered.     

Cross-scale Habitat Structure Drives Fish Body Size Distributions on Coral Reefs

Despite a large number of studies focusing on the complexity of coral reef habitats and the characteristics of associated fish assemblages, the relationship between reef structure and fish assemblages remains unclear. The textural discontinuity hypothesis, which proposes that multi-modal body size distributions of organisms are driven by discontinuous habitat structure, provides a theoretical basis that may explain the influence of habitat availability on associated organisms. In this study we use fractal techniques to characterize patterns of cross-scale habitat complexity, and examine how this relates to body-depth abundance distributions of associated fish assemblages over corresponding spatial scales. Our study demonstrates that: (1) Reefs formed from different underlying substrata exhibit distinct patterns of cross-scale habitat complexity; (2) The availability of potential refuges at different scales correlates with patterns in fish body depth distributions, but habitat structure is more strongly related to the relative abundance of fish in the body depth modes, rather than to the number of modes; (3) As reefs change from coral- to algal-dominated states, the complexity of the underlying reef substratum may change, presenting a more homogenous environment to associated assemblages; (4) Individual fish body depth distributions may be multi-modal, however, these distributions are not static characteristics of the fish assemblage and may change to uni-modal forms in response to changing habitat condition. In light of predicted anthropogenic changes, there is a clear need to improve our understanding of the scale of ecological relationships to anticipate future changes and vulnerabilities.     

Reef fish assemblages in north-western Sri Lanka: distribution patterns and influences of fishing practises

The distribution and abundance of reef fishes in relation to habitat structure were studied within Bar Reef Marine Sanctuary (BRMS) and on an adjacent reef, disturbed by destructive fishing techniques, in north-western Sri Lanka, by visually censusing 135 species groups using fifty metre belt-transects. Two types of continental shelf patch-reefs are found in the study area: coral reefs and sandstone reefs, which are divided into distinct habitats, four for the coral reef (shallow reef flat, shallow patch reef, deep reef flat and Porites domes) and two for the sandstone reef (structured sandstone-reef and flat sandstone-reef). Fish assemblages varied in structure between reef types and among habitats within reef types. Functional aspects of habitat structure and composition, such as available food and shelter, seemed to be important factors influencing distribution patterns. The strongest separation in the organisation of fish assemblages in BRMS was between reef types: 19% of all species were confined to the coral-reef patches while 22% were restricted to the sandstone reef patches and 59% were represented on both reef types. In terms of distribution among habitats, 21% of all species were restricted to one habitat while only 1.5% were present in all. The highest density of fish was in the coral reef habitats while highest species diversity was found in the most structurally complex habitat: the structured sandstone-reef. This habitat also had the highest proportion of species with restricted distribution. Planktivores were the most abundant trophic group in BRMS, and the species composition of the group varied among habitats. The comparison of the disturbed reef with BRMS suggested that habitat alteration caused by destructive fishing methods has strongly influenced the fish community. Within the fished area the structure of the fish assemblages was more heterogeneous, fish abundance was lower by an order of magnitude and species numbers were lower than in BRMS.     

Local vs regional effects of substratum on early colonization stages of sessile assemblages

Substratum type and topographic complexity influence the settlement and persistence of benthic organisms. However, the combined effect of these two factors in affecting colonization patterns at different scales has rarely been investigated. A manipulative experiment was conducted to test the interplay of rock type and roughness in affecting the pattern of subtidal assemblages and to provide tests for the generality of effects across a range of spatial scales (centimetres to hundreds of metres). Replicate tiles of four different rock types, with two levels of surface roughness were deployed in rocky subtidal habitats (5 m depth) at two sites (separated by hundreds of metres) at each of three locations (separated by tens of kilometres). Spatial and temporal variation in the colonization patterns over 9 months differed among rock types. However, large-scale processes appeared to be far more important than substratum type or roughness in determining assemblage structure. Predicting the consequences of the introduction of artificial structures into the coastal marine environment is critical as increasingly parts of coastlines are being modified within the Mediterranean and other regions. The results suggest that further investment is needed to manage and mitigate the effects of the deployment of artificial structures in coastal areas.     

Community regulation: the relative importance of recruitment and predation intensity of an intertidal community dominant in a seascape context

Predicting the strength and context-dependency of species interactions across multiple scales is a core area in ecology. This is especially challenging in the marine environment, where populations of most predators and prey are generally open, because of their pelagic larval phase, and recruitment of both is highly variable. In this study we use a comparative-experimental approach on small and large spatial scales to test the relationship between predation intensity and prey recruitment and their relative importance in shaping populations of a dominant rocky intertidal space occupier, mussels, in the context of seascape (availability of nearby subtidal reef habitat). Predation intensity on transplanted mussels was tested inside and outside cages and recruitment was measured with standard larval settlement collectors. We found that on intertidal rocky benches with contiguous subtidal reefs in New Zealand, mussel larval recruitment is usually low but predation on recruits by subtidal consumers (fish, crabs) is intense during high tide. On nearby intertidal rocky benches with adjacent sandy subtidal habitats, larval recruitment is usually greater but subtidal predators are typically rare and predation is weaker. Multiple regression analysis showed that predation intensity accounts for most of the variability in the abundance of adult mussels compared to recruitment. This seascape-dependent, predation-recruitment relationship could scale up to explain regional community variability. We argue that community ecology models should include seascape context-dependency and its effects on recruitment and species interactions for better predictions of coastal community dynamics and structure.     

Integrating ecology with biogeography using landscape characteristics: a case study of subtidal habitat across continental Australia

Aim We aimed to redress a current limitation of local ecological studies (i.e. piecemeal information on specific taxa) by integrating existing ecological knowledge with quantifiable patterns in primary habitat (i.e. composition, distribution and cover) from local to continental scales. By achieving this aim, we sought to provide a biogeographical framework for the interpretation of variation in the ecology of, and threats to, subtidal rocky landscapes. Location The subtidal rocky coast of continental Australia, with longitudinal comparisons spanning > 4000 km of southern coast (115°03′ E–153°60′ E) between latitudes of 33°05′ S and 35°36′ S, and latitudinal comparisons across 26°40′ S to 37°08′ S of eastern Australia. Methods The frequency and size of patches of major benthic habitat were quantified to indicate contemporary function (ecology) and to establish patterns that may result from contrasting regional‐scale processes (biogeography). This was achieved by quantifying the composition and patchiness of key subtidal habitats across the continent and relating them to the known ecology of subsets of locations in each region. A nested design of several spatial scales (1000s, 100s, 10–1 km) was adopted to distinguish patterns at local through to biogeographical scales. Results We show biogeography (in terms of longitude and latitude) to have a fundamental influence on the patterns of abundance and composition of subtidal habitats across regional (1000s of kilometres) to local (10s of kilometres to metres) scales. Across the continent, the most fundamental patterns related to (1) the proportion of rock covered by kelp forests, as related to particular functional groups of herbivores, and (2) the small‐scale heterogeneity (metres) that characterizes these forests. Main conclusions We interpret these results within a framework of alternative processes known to maintain habitat heterogeneity across these regions (e.g. productivity versus consumption as shapers of habitat structure). These interpretations illustrate how regional differences in ecological patterns and processes can create contradictory outcomes for the management of natural resources. We suggest that researchers and managers of natural resources alike may benefit from understanding local issues (e.g. the effects of fishing and its synergies with water pollution) in their biogeographical contexts.     

枸杞岛潮下带沙地生境鱼类群落结构和季节变化

为了解岛礁水域沙地生境的鱼类群落结构特征,评估该生境对鱼类资源养护的潜在作用,于2009年采用多网目组合刺网对枸杞岛潮下带沙质区域进行了逐月采样,同步设置岩礁为对照生境.应用α和β多样性指数结合相对重要性指数、相对渔获率、ABC曲线和聚类排序方法对两种生境中的鱼类组成、多样性变化和群落格局与变化进行了全面探讨.全年在沙地和岩礁生境共采集鱼类63种,隶属11目38科56属,2种生境各自出现的鱼类皆为46种.受暖水种频繁出现在沙地生境的影响,潮下带沙质区域鱼类区系比岩礁生境略显丰富,且春夏季的渔获量普遍高于岩礁生境;由于种类组成均匀度较低,沙地生境各季节的α多样性普遍较低,夏季显著低于岩礁生境.日本须鳎是沙地生境的指示种,为早春、夏末和秋冬季沙地底层优势鱼种.5-7月鳀、多数月份鲻和10月份鳗鲇等种类对沙地生境的阶段性利用,使其形成了区别于以趋礁性鱼类为优势类群的岩礁生境的群落格局和季节动态.沙地是多种鱼类幼鱼阶段的庇护所和饵料场,是鲆鲽类的良好栖息地.沙地生境在维持鱼类区系和养护鱼类资源方面具有重要作用.     

马鞍列岛岩礁生境鱼类群落生态学.Ⅰ.种类组成和多样性

为了解潮下带岩礁生境的鱼类区系特征,于2009年对马鞍列岛岩礁生境进行了12个月的多网目组合刺网采样,从分类学和生态型组成等方面,结合多样性和相对重要性指数,对该生境的鱼类组成和多样性特征进行了分析。全年共采集鱼类87种,隶属2纲14目50科73属。其中鲈形目鱼类51种,占58.6%;趋礁性鱼类49种,占56.3%;放流鱼类7种,占8%。所有鱼类个体中,幼鱼的总比例为67.4%。暖水种、暖温种和冷温种分别为50、36和1种;底层、近底层和中上层鱼类各为19、46和22种,其中褐菖鲉(Sebasti scus marmoratus)、黄姑鱼(Nibea albiflora)和赤鼻棱鳀(Thryssa kammalensis)分别为各水层的绝对优势种;定居种、季节性洄游种和偶见种各为32、55和11种。岩礁生境鱼类多样性呈现明显的季节变化特征,2月份最低,9月份最高。研究结果表明,马鞍列岛岩礁生境是以趋礁鱼类为特征群体、暖水性和暖温性鱼类共同主导、各个类型的幼鱼在夏秋季集群出现、同时也分布了一定量放流种的高鱼类多样性栖息地,它为各种鱼类提供了优良的摄食、避敌和繁殖场所,是近岸海洋生态系统中相当重要的生境。然而相比过去,该生境的鱼类多样性已经大大降低,因此需对其保护工作予以更多关注。     

Forgotten underwater forests: The key role of fucoids on Australian temperate reefs

Kelp forests dominated by species of Laminariales are globally recognized as key habitats on subtidal temperate rocky reefs. Forests characterized by fucalean seaweed, in contrast, receive relatively less attention despite being abundant, ubiquitous, and ecologically important. Here, we review information on subtidal fucalean taxa of Australia's Great Southern Reef, with a focus on the three most abundant and widely distributed genera (Phyllospora, Scytothalia, and Sargassum) to reveal the functionally unique role of fucoids in temperate reef ecology. Fucalean species span the entire temperate coastline of Australia (~71,000 km²) and play an important role in supporting subtidal temperate biodiversity and economic values on rocky reefs as well as in adjacent habitats. Climatic and anthropogenic stressors have precipitated significant range retractions and declines in many fucoids, with critical implications for associated assemblages. Such losses are persistent and unlikely to be reversed naturally due to the life history of these species and colonization of competitors and grazers following loss. Active restoration is proving successful in bringing back some fucoid species (Phyllospora comosa) lost from urban shores and will complement other passive and active forms of conservation. Fucalean forests play a unique role on subtidal temperate reefs globally, especially in Australia, but are comparatively understudied. Addressing this knowledge gap will be critical for understanding, predicting, and mitigating extant and future loss of these underwater forests and the valuable ecosystem services they support.