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Topographic heterogeneity sets the stage for community assembly, but its effects on ecosystem functioning remain poorly understood. Here, we test the hypothesis that topographic heterogeneity underpins multiple cascading species interactions and functional pathways that indirectly control multifunctionality. To do so, we combined experimental manipulation of a form of topographic heterogeneity on rocky shores (holes of various sizes) with a comprehensive assessment of naturally assembled communities and multifunctionality. Structural equation modeling indicated that heterogeneity: (1) enhanced biodiversity by supporting filter feeder richness; (2) triggered a facilitation cascade via reef‐forming (polychaete) and biomass‐dominant (macroalga) foundation species, which in turn broadly supported functionally diverse epibiotic and understory assemblages; and (3) inhibited a key consumer (limpet). The model supported that these mechanisms exerted complementary positive effects on individual functions (e.g., water filtration, ecosystem metabolism, nutrient uptake) and, in turn, collectively enhanced multifunctionality. Topographic heterogeneity may therefore serve as a cornerstone physical attribute by initiating multiple cascades that propagate through ecological communities via foundation species, ultimately manifesting disproportionate effects on ecosystem multifunctionality. [ABSTRACT FROM AUTHOR]

Coral reefs face threats from climate change and local pressures that lead to reductions in their physical structure, impacting biodiversity by limiting habitat availability. Despite many efforts to actively restore damaged reefs, few projects provide thorough evaluations of their success. This study measured the success of the “Reef Star” method at the Mars Coral Reef Restoration Project in Indonesia in reestablishing the physical structure of reef habitats that were destroyed by blast fishing. We used photogrammetry surveys to measure the physical habitat structure of 17 large sites (1000 m2 each), calculating three complementary measures of small‐ and large‐scale habitat complexity across degraded, restored, and naturally healthy coral reefs. We demonstrate that the restoration efforts have successfully restored small‐scale habitat complexity, as described by surface complexity metrics (3.22 ± 0.27 on restored reefs; 2.85 ± 0.26 on healthy reefs) and fractal dimension (2.27 ± 0.02 on restored reefs; 2.24 ± 0.02 on healthy reefs). This demonstrates the capacity for restored reefs to recover important ecosystem functions that are lost in degradation. However, while restoration has delivered some increases in large‐scale habitat complexity compared to degraded reefs, restored reefs still exhibit lower values of maximum vertical relief than healthy reefs, due to a lack of large physical structures. This lack of available large‐scale habitat might impact fish populations, meaning that restored reefs with limited large‐scale complexity may only support a restricted range of ecosystem functions. Effective reef restoration strategies must use a mixture of different methods that target the recovery of structural complexity at multiple scales. [ABSTRACT FROM AUTHOR]

Arizona toad (Anaxyrus microscaphus) is a stream‐breeding bufonid of conservation concern in Arizona, New Mexico, Utah, and Nevada. We determined the occupancy and habitat use of the Arizona toad throughout its range. We surveyed 500‐m reaches along perennial and intermittent streams during the summers of 2021 and 2022 (n = 232) in Arizona. We recorded the presence of all toad life stages, focusing on larval stages. We related toad occupancy to broadscale environmental variables, including measures of bioclimate, habitat heterogeneity, solar radiation, and topography. We collected fine‐scale variables to summarize vegetation cover and substrate within plots (n = 53). We applied multiple occupancy models. Single‐species model results found low toad occupancy with high detection. Two principal component analyses (PCA) were run on broadscale and fine‐scale variables to reduce the number of variables included in the models. Toad occupancy was best predicted by top models with bioclimatic components; occupancy decreases with extremely hot temperatures and less precipitation. A logistic regression related toad presence to fine‐scale components with top models describing riparian complexity and algae. Arizona toads were selected for areas with foliar canopy cover, shallow water, algae cover, and pebble substrates. Arizona toad is an uncommon species and maintaining riparian forests of complex habitats with shallow and side‐channel flow will be important for toad conservation. Implications of less water cause riparian habitat to dry, which ultimately harms aquatic life. [ABSTRACT FROM AUTHOR]

Context: In Western Australia, the heritage-listed Busselton Jetty is a popular tourism, fishing and diving destination renowned for its unique marine communities. Aims: This research describes and quantifies the fish assemblages (mean number of individuals, species diversity and biomass) at the Busselton Jetty, and makes comparisons with natural habitats in Geographe Bay. Methods: Diver-operated stereo-video systems filmed 25-m transects along the length of the jetty, and a remotely operated vehicle stereo-video filmed 25-m transects in nearby reef, seagrass and sand habitats. Fish at all habitats were counted, identified and measured. Results: Fish assemblages at the defined inshore, mid-shore and offshore zones of the jetty differed significantly, whereas the number of fish, species diversity and biomass increased with distance from shore. There was no measurable effect of protection within the small sanctuary zone at the end of the jetty. Fish assemblages at the jetty differed from those in all three natural habitats, and the number of fish, species diversity and biomass were highest at the natural reef, followed by the jetty, the seagrass and the sand habitats. Conclusions: The Busselton Jetty supports a distinctive fish assemblage, high species diversity and a variety of benthic communities. Changes in the fish assemblages were attributed to differences in habitat type, complexity, depth and distance from shore. Implications: The ecological and social benefits of future man-made marine structures can be optimised by incorporating design features that promote habitat diversity and complexity. We described and quantified the fish assemblages at the heritage-listed Busselton Jetty, and made comparisons with natural reef, seagrass and sand habitats in Geographe Bay. The mean number of fish, species diversity and biomass all increased with distance along the jetty. The fish assemblage at the jetty was unique and different from that in all three natural habitats. Habitat complexity, depth and distance from shore were the key drivers of these differences. [ABSTRACT FROM AUTHOR]

Coral reef fishes are usually assumed to be most strongly associated with reef-building corals. However, sponges can be a significant structural component of coral reef ecosystems and their framework can enhance the local abundance and biodiversity of fish assemblages. Little is known regarding the range of fish species using complex sponges as either shelter or feeding substrata. Here we use a combination of stationary video cameras and focal animal sampling to document fish species positively associated with complex sponges in Kimbe Bay, Papua New Guinea. Stationary cameras identified 45 fish species using the sponges for either shelter, feeding substrata or as sites for ambush predation. A guild of 10 individual fish species from five families (Blenniidae, Chaetodontidae, Gobiidae, Labridae and Pomacentridae) were observed to quantify sponge and other habitat use and compared with habitat availability to determine the level of sponge selectivity. One species, Pleurosicya elongata (the Slender Spongegoby), lived in obligate association with Ianthella basta (Elephant Ear sponge), and there was a positive relationship between sponge size and number of resident fish, however this was not significant for all life stages. Five other fish species appeared to preferentially select sponges as habitat (Amblyglyphidodon aureus, Chaetodon kleinii, Coradion chrysozonus, Escenius prooculis and Pomacentrus nigromanus), while for others, sponge use appeared incidental. When selectivity indices were calculated for specific sponge species it was apparent that some fishes exhibited preferences for particular sponge species or growth forms. These results suggest more fish species may be reliant on sponges than is widely appreciated. [ABSTRACT FROM AUTHOR]

Coral reef ecosystems are facing severe degradation due to anthropogenic activities at both local and global scales. In response, extensive restoration efforts are underway, aiming to bolster coral cover and enhance reef fish communities to foster facilitation between fish and corals. This reciprocal relationship is anticipated to improve overall restoration efficacy and enhance coral reef resilience in the face of global warming. Here, we investigate the impact of coral restoration using out-planted Acropora cervicornis colonies attached to raised domes on the associated fish community on the isolated, well-protected reef of Little Cayman Island in the Central Caribbean. Surveys were conducted immediately preceding out-planting, five days later, and 85 days later to capture temporal changes in the fish community. After 85 days of out-planting, there were no changes in fish biomass, abundance, or species richness for the entire fish community. This pattern was consistent for selected fish functional groups. Additionally, no significant differences were observed in the fish community before outplanting, five days after out-planting, or 85 days after out-planting of restoration domes. Our results underscore the limited impact of coral restoration for influencing fish communities in the isolated and highly protected reef of Little Cayman over an 85-day period. Consequently, our findings have implications for using coral restoration as a mechanism to enhance fish populations, particularly in marginally disturbed regions where structural complexity has not been lost. Future restoration programs should therefore incorporate local knowledge of environmental history and restoration needs along with an increased data-driven understanding of the intricate interaction between fish and coral populations to be successful. [ABSTRACT FROM AUTHOR]

Birds use their visual systems for important tasks, such as foraging and predator detection, that require them to resolve an image. However, visual acuity (the ability to perceive spatial detail) varies by two orders of magnitude across birds. Prior studies indicate that eye size and aspects of a species' ecology may drive variation in acuity, but these studies have been restricted to small numbers of species. We used a literature review to gather data on acuity measured either behaviorally or anatomically for 94 species from 38 families. We then examined how acuity varies in relation to (1) eye size, (2) habitat spatial complexity, (3) habitat light level, (4) diet composition, (5) prey mobility, and (6) foraging mode. A phylogenetically-controlled model including all of the above factors as predictors indicated that eye size and foraging mode are significant predictors of acuity. Examining each ecological variable in turn revealed that acuity is higher in species whose diet comprises vertebrates or scavenged food and whose foraging modes require resolving prey from farther away. Additionally, species that live in spatially-complex, vegetative habitats have lower acuity than expected for their eye sizes. Together, our results suggest that the need to detect important objects from far away-such as predators for species that live in open habitats, and food items for species that forage on vertebrate and scavenged prey-has likely been a key driver of higher acuity in some species, helping to elucidate how visual capabilities may be adapted to an animal's visual needs.

Vegetation connectivity is an essential aspect of the habitat complexity that impacts species interactions at local scales. However, agricultural intensification reduces connectivity in agroforestry systems, including coffee agroecosystems, which may hinder the movement of natural enemies and reduce the ecosystem services that they provide. Ants play an important role in regulating the coffee berry borer (CBB), which is the most damaging coffee pest. For arboreal ant communities, the connections between trees are important structures that facilitate ant mobility, resource recruitment, foraging success, and pest control ability. To better understand how connectivity impacts arboreal ants in coffee agroecosystems, we conducted an experiment to assess the impact of artificial (string) and naturally occurring vegetation (vines, leaves, branches) connectivity on Azteca sericeasur behavior on coffee plants. We compared ant activity, resource recruitment, and CBB removal rates across three connectivity treatments connecting coffee plants to A. sericeasur nest trees: vegetation connectivity, string, and control (not connected) treatments. We found higher rates of ant activity, resource recruitment, and CBB removal on plants with naturally occurring vegetation connections to A. sericeasur nest trees. Artificial connectivity (string) increased the rates of resource recruitment and CBB removal but to a lesser extent than vegetation connectivity. Moreover, vegetation connectivity buffered reductions in ant activity with distance from the ant nest tree. These results reinforce how habitat complexity in the form of vegetation connectivity impacts interspecific interactions at the local scale. Our results also suggest that leaving some degree of vegetation connectivity between coffee plants and shade trees can promote ant-mediated biological pest control in coffee systems.

Abstract Artificial reefs (AR), which are integral tools for fish management, ecological reconciliation and restoration efforts, require non-polluting materials and intricate designs that mimic natural habitats. Despite their three-dimensional complexity, current designs nowadays rely on empirical methods that lack standardised pre-immersion assessment. To improve ecosystem integration, we propose to evaluate 3-dimensional Computer-aided Design (3D CAD) models using a method inspired by functional ecology principles. Based on existing metrics, we assess geometric (C-convexity, P-packing, D-fractal dimension) and informational complexity (R-specific richness, H- diversity, J-evenness). Applying these metrics to different reefs constructed for habitat protection, biomass production and bio-mimicry purposes, we identify potential complexity target points (CTPs). This method provides a framework for improving the effectiveness of artificial reef design by allowing for the adjustment of structural properties. These CTPs represent the first step in enhancing AR designs. We can refine them by evaluating complexity metrics derived from 3D reconstructions of natural habitats to advance bio-mimicry efforts. In situ, post-immersion studies can help make the CTPs more specific for certain species of interest by exploring complexity-diversity or complexity-species distribution relationships at the artificial reef scale.

Considering the food diversity of natural enemy species and the habitat complexity of prey populations, a pest-natural enemy model with non-monotonic functional response is proposed for biological management of Bemisia tabaci. The dynamic characteristics of the proposed model are analyzed. In addition, considering that the conversion from prey to predator has a certain time lag rather than instantaneous, a time delay is introduced into this model, and it is shown that the Hopf bifurcation occurs at the interior equilibrium when the time delay is used as the bifurcation parameter. Furthermore, the values of the parameters that determine the direction of the Hopf bifurcation as well as the stability of the periodic solution are calculated. In order to illustrate the theoretical analysis results, numerical simulations and validation are carried out to demonstrate the effects of non-monotonic functional response, additional food supply and habitat complexity. [ABSTRACT FROM AUTHOR]

The interacting threats of invasive predators and altered fire regimes are key conservation issues for many native species globally. Artificial refuges have been proposed as a potential conservation tool to provide prey species with protection from invasive predators after fire, but we do not yet know whether they improve animal survival. To address this knowledge gap, we experimentally tested how small mammal abundance and species richness were influenced by the provision of artificial refuges after prescribed burns. We surveyed small mammals across five unburnt sites, seven burnt sites with artificial refuges, and eight burnt control sites following two prescribed fires in southeastern Australia. There were negative and neutral responses of small mammals to the burns, and relative abundance was positively correlated with structurally complex vegetation. Artificial refuges had no impact on abundance or species richness, irrespective of burn coverage. These findings suggest that this artificial refuge design may not be an effective tool for improving small mammal population persistence postfire, and as such we should not yet scale up their application. However, given the inherent context‐dependency of field experiments involving fire, which include difficult‐to‐control variables such as fire severity, predator activity, and population dynamics, we encourage researchers to undertake further experiments with artificial refuges in fire‐affected areas, including after severe wildfires when less vegetation cover remains. Such studies will help to build our understanding of their utility as a conservation tool across different ecosystems and fire types. [ABSTRACT FROM AUTHOR]

Kelp forests provide habitat for many species, but it remains uncertain whether specific kelp forest types support distinct biodiversity. Surface canopy-forming giant kelp (Macrocystis pyrifera) forests in Tasmania, Australia, have declined significantly due to climate change, and have been widely replaced by forests dominated by smaller stipitate kelps like Ecklonia radiata. However, there is limited knowledge of the community composition of Macrocystis forests and how this may differ from the stipitate kelp forest community. Underwater visual census surveys were conducted of the fishes and macroinvertebrates (> 2.5 cm length) in remnant Macrocystis forests in south-eastern Tasmania, and in adjacent stipitate kelp forests. 18 sites (9 of each forest type) were surveyed across two regions during the period of peak growth and canopy cover (i.e. winter-spring). Faunal community composition varied little between forest types, although Macrocystis forests supported more than double the abundance and biomass of mobile fishes, while cryptic fishes differed by forest type depending on region. Macroinvertebrate assemblages did not differ between forest types nor regions. Thus, for the taxa and time period examined, Tasmanian Macrocystis and stipitate kelp forests supported mostly similar faunal communities. Kelp forest communities showed spatial variation and were also likely influenced by a variety of other habitat characteristics, such as the relatively small patch sizes and/or ephemeral state of the remnant Macrocystis forests. Quantifying the community structure of these endangered communities informs the ecological changes that have occurred and will serve as an important reference for ongoing conservation and restoration activities. [ABSTRACT FROM AUTHOR]

Researchers often use surrogate species for assessing biodiversity—organisms that can indicate the presence of additional taxa or provide insight into environmental processes. As indicators of anthropogenic impact, "cross‐taxon" surrogates are theorized to be effective shortcuts for determining how communities respond to environmental change. However, few studies have implemented cross‐taxon surrogates given the challenge of validating the strength of the relationship between surrogates and their target taxa. Trophically transmitted parasites require multiple invertebrate and vertebrate taxa to complete their life cycles (e.g., annelids, mollusks, fishes, shorebirds), making them ideal cross‐taxon surrogates of community diversity. By sampling for these parasite surrogates, it is theoretically possible to infer the composition of the overall host community based on the species of parasites present. In our study, we tested the use of parasites as cross‐taxon surrogates of biodiversity by sampling for digenetic trematodes in the mudsnail Ilyanassa obsoleta, collected from coastal shoreline environments with or without artificial structures (e.g., bulkheads, seawalls). We found that trematode richness, evenness, and diversity were all greater in snails sampled from natural shorelines versus those with artificial structures. While parasite communities clustered by shoreline type (with vs. without artificial structures), we found no differences in multivariate dispersion, or beta‐diversity, between groups in our system. At the species level, trematodes requiring polychaetes and estuarine fishes as downstream hosts dominated parasite communities at shorelines with artificial structures. These taxa are ubiquitous but more abundant in degraded environments. In contrast, trematode species requiring mollusks and shorebirds as hosts was only documented from shorelines without artificial structures (i.e., natural), which may indicate that these areas are less degraded and have greater overall host diversity. High parasite diversity in easily collected hosts (e.g., mudsnails) provides evidence that the secondary (polychaetes, crustaceans) and tertiary (fishes, shorebirds) hosts required by the parasites are present in the system. Our study also helps validate the concept of surrogate species by demonstrating how a single species can represent broader taxonomic groups. [ABSTRACT FROM AUTHOR]

In this paper, a population system with cross-diffusion and habitat complexity is selected as study object. We investigate that how cross-diffusion and habitat complexity destabilize the otherwise stable periodic solutions of the ODEs to generate the new abundant spatial Turing patterns. By utilizing the local Hopf bifurcation theorem and perturbation theory, we establish a formula to determine the Turing instability of periodic solutions of the population system with cross-diffusion and habitat complexity. Finally, numerical simulations are performed to verify theoretical analysis, simultaneously, we verify the formation process of spatial Turing patterns when the cross-diffusion coefficients and habitat complexity change. [ABSTRACT FROM AUTHOR]

In this review, we explore the understanding of habitat complexity influencing the bird community with a special focus on Malaysia's recent case studies. Malaysia is one of the mega-diverse countries because it is gifted with the beauty of biodiversity. However, biodiversity resources are greatly affected by human activities such as mining operations, agricultural expansion, timber extraction, and hunting activity. In bird ecological research, habitat complexity is crucial because it affects biodiversity overall within species interactions and resource availability by evaluating environmental features including floristic composition and habitat heterogeneity. The positive relationship between habitat complexity and species diversity has been extensively documented. Complex habitats provide a variety of resources and niches, allowing different species to coexist. However, the advanced research methodologies, long-term monitoring, and a more nuanced understanding of the specific ecological processes influencing bird populations should be well emphasized. This review intends to fill in the gaps by critically analyzing potential conservation management strategies that might be adopted to increase habitat connectivity and minimize the negative effects of habitat loss on bird community structures in Malaysia. [ABSTRACT FROM AUTHOR]

The health of coral reef benthic and fish communities is implicitly connected, yet typically studied and managed separately. By developing a coupled reef population model that connects coral populations and reef fish biomass through the habitat complexity that corals build and fish live among, we aim to address this gap by holistically quantifying ecological feedbacks and responses to ecological stressors. We explored the impacts of fishing effort in conjunction with three types of ecological disturbances as they propagated through a coral reef ecosystem: (1) a disturbance that disproportionately affected small, bio‐energetically vulnerable colonies, (2) a disturbance that predominantly affected large, mechanically vulnerable colonies, and (3) a disturbance that affected colonies of all sizes randomly. We found that joint coral and fish population recovery was fastest and most complete under events affecting small colonies, followed by recovery from disturbances affecting random sizes, and lastly large‐colony disturbances. These results suggest that the retention versus loss of large coral colonies with high reproductive potential critically influenced population recovery. Low fishing levels maintained fish and coral populations and allowed for recovery after disturbances, whereas high fishing levels prevented recovery due to greater fish‐dependent coral mortality. Finally, we tested various formulations of the relationship between coral size and habitat complexity (i.e., exponential, linear, logarithmic) that constrain fish carrying capacity. All formulations led to similar population projections in most disturbance scenarios, but there were exceptions where the timing and trajectory of recovery differed, such as faster and greater recovery potential when complexity is logarithmic with respect to coral size. These findings suggest that fishing and habitat complexity mediate the recovery of coral reef populations, emphasizing the importance of describing linkages between coral size distribution and reef habitat structure. Furthermore, our results highlight the utility of the coupled‐model framework for understanding and managing the impact of disturbances at ecosystem scales. [ABSTRACT FROM AUTHOR]

Among-individual variation in predator traits is ubiquitous in nature. However, variation among populations in this trait variation has been seldom considered in trophic dynamics. This has left unexplored (a) to what degree does among-individual variation in predator traits regulate prey populations and (b) to what degree do these effects vary spatially. We address these questions by examining how predator among-individual variation in functional traits shapes communities across habitats of varying structural complexity, in field conditions. We manipulated Chinese mantis (Tenodera sinensis) density (six or twelve individuals) and behavioral trait variability (activity level by movement on an open field) in experimental patches of old fields with varying habitat complexity (density of plant material). Then, we quantified their impacts on lower trophic levels, specifically prey (arthropods > 4 mm) and plant biomass. Predator behavioral variability only altered prey biomass in structurally complex plots, and this effect depended on mantis density. In the plots with the highest habitat complexity and mantis density, behaviorally variable groups decreased prey biomass by 40.3%. In complex plots with low mantis densities, low levels of behavioral variability decreased prey biomass by 32.2%. Behavioral variability and low habitat complexity also changed prey community composition, namely by increasing ant biomass by 881%. Our results demonstrate that among-individual trait variation can shape species-rich prey communities. Moreover, these effects depend on both predator density and habitat complexity. Incorporating this important facet of ecological diversity revealed normally unnoticed effects of functional traits on the structure and function of food webs. [ABSTRACT FROM AUTHOR]

Sustainable pest management requires growers and regional land managers to consider the relationships among pest management practices, pest and natural enemy communities, crop loss, and multi-scalar habitat complexity. However, the causal links among these variables, in particular potential interactions between landscape and local-scale habitat complexity, remain underexplored. In the context of organically managed strawberry crops in California’s Central Coast, we tested the independent effects of landscape and local habitat complexity gradients on arthropod communities and crop loss using a piecewise structural equation model (PSEM). We found that landscape-scale woody habitat proportion indirectly decreased crop loss through its positive effect on natural enemy abundance, while grassland proportion had the opposite effect due to its association with an important strawberry pest (Lygus spp.). We detected a pattern suggesting that on-farm diversification practices are most effective at reducing crop loss at an intermediate level (26%) of woody habitat proportion. Both organic-compliant insecticide application and tractor vacuuming negatively impacted natural enemies, and therefore had qualified effects on crop loss. Our study shows the key roles of native woodlands and natural enemy communities in reducing crop loss and highlights the importance of managing habitat complexity at both landscape and local scales.

Coral reef ecosystems are facing severe degradation due to anthropogenic activities at both local and global scales. In response, extensive restoration efforts are underway, aiming to bolster coral cover and enhance reef fish communities to foster facilitation between fish and corals. This reciprocal relationship is anticipated to improve overall restoration efficacy and enhance coral reef resilience in the face of global warming. Here, we investigate the impact of coral restoration using out-planted Acropora cervicornis colonies attached to raised domes on the associated fish community on the isolated, well-protected reef of Little Cayman Island in the Central Caribbean. Surveys were conducted immediately preceding out-planting, five days later, and 85 days later to capture temporal changes in the fish community. After 85 days of out-planting, there were no changes in fish biomass, abundance, or species richness for the entire fish community. This pattern was consistent for selected fish functional groups. Additionally, no significant differences were observed in the fish community before outplanting, five days after out-planting, or 85 days after out-planting of restoration domes. Our results underscore the limited impact of coral restoration for influencing fish communities in the isolated and highly protected reef of Little Cayman over an 85-day period. Consequently, our findings have implications for using coral restoration as a mechanism to enhance fish populations, particularly in marginally disturbed regions where structural complexity has not been lost. Future restoration programs should therefore incorporate local knowledge of environmental history and restoration needs along with an increased data-driven understanding of the intricate interaction between fish and coral populations to be successful.

The urgency of the biodiversity crisis calls for high-quality habitat data now. Ground-based images (GBIs) represent one of the least-utilized fine-grain data sources with a worldwide coverage and low acquisition cost. The integration of GBIs with other data sources and computer vision can provide objective approaches to improve species–habitat models. We need to understand how GBIs complement existing remote sensing resources, and develop standardized descriptive statistics characterizing the composition and complexity of GBIs. Fine-grained environmental data across large extents are needed to resolve the processes that impact species communities from local to global scales. Ground-based images (GBIs) have the potential to capture habitat complexity at biologically relevant spatial and temporal resolutions. Moving beyond existing applications of GBIs for species identification and monitoring ecological change from repeat photography, we describe promising approaches to habitat mapping, leveraging multimodal data and computer vision. We illustrate empirically how GBIs can be applied to predict distributions of species at fine scales along Street View routes, or to automatically classify and quantify habitat features. Further, we outline future research avenues using GBIs that can bring a leap forward in analyses for ecology and conservation with this underused resource. [ABSTRACT FROM AUTHOR]

Understanding species–habitat relationships is essential for ecosystem-based conservation. This study explores the significance of habitat characteristics and complexity for demersal and benthopelagic communities within a patchwork of coastal habitats, including rocky seabed, macroalgae formations, sandy bottoms, and a combination of rock and sand areas. Species and habitats were surveyed along the north-west (NW) Iberian continental shelf area of Viana do Castelo using baited remote underwater video stations (BRUVS). We found significant differences (p < 0.05) in species assemblages across habitats, with rocky substrates showing the highest diversity and abundance. Sand habitats showed the lowest species richness and abundance, underscoring the importance of habitat complexity to support marine life. Our study also emphasises the role of specific species in shaping the communities, identifying key species such as Trisopterus luscus, Diplodus vulgaris, and Ctenolabrus rupestris as the three most abundant in the region and significant contributors to the observed dissimilarities between habitats. By elucidating the impact of habitat complexity on marine life, our results offer essential baseline data, which serve as a kick-start point to inform sustainable management and conservation strategies for the long-term health and productivity of these vital ecological systems in the North-East Atlantic. [ABSTRACT FROM AUTHOR]

Cognitive abilities vary within and among species, and several hypotheses have been proposed to explain this variation. Two of the most prominent hypotheses regarding the evolution of cognition link increased social and habitat complexity with advanced cognitive abilities. Several studies have tested predictions derived from these two hypotheses, but these were rarely conducted under natural conditions with wild animals. However, this is of particular importance if we aim to link cognitive abilities with fitness-relevant factors to better understand the evolution of cognition. The biggest hurdle to assessing cognition in the wild is to find a suitable setup that is easy to use under field conditions. Here, we set out to evaluate an extremely simple test of cognitive ability for use with a broad range of aquatic animals in their natural habitat. We did so by developing a detour test paradigm in which fish had to detour a clear obstacle to reach a food reward. By altering the difficulty of the task, we confirmed that this setup is a valid test of cognitive abilities in wild groups of a Lake Tanganyika cichlid, Neolamprologus pulcher. Subsequently, we probed specific predictions from the two major hypotheses regarding cognitive evolution using the most difficult test configuration. Specifically, we tested the variation in cognitive abilities among groups of different sizes occupying habitats of varying complexity. We find mixed support for both hypotheses, but we hope that our work inspires future investigations on the evolution of cognition in Lake Tanganyika cichlids. [ABSTRACT FROM AUTHOR]

Context: The distribution of animals is influenced by a complex interplay of landscape, environmental, habitat, and anthropogenic factors. While the effects of each of these forces on fish assemblages have been studied in isolation, the implications of their combined influence within a seascape remain equivocal. Objectives: We assessed the importance of local habitat composition, seascape configuration, and environmental conditions for determining the abundance, diversity, and functional composition of fish assemblages across a tropical seascape. Methods: We quantified fish abundance in coral, macroalgal, mangrove, and sand habitats throughout the Dampier Archipelago, Western Australia. A full-subsets modelling approach was used that incorporated data from benthic habitat maps, a hydrodynamic model, in situ measures of habitat composition, and remotely sensed environmental data to evaluate the relative influence of biophysical drivers on fish assemblages. Results: Measures of habitat complexity were the strongest predictors of fish abundance, diversity, and assemblage composition in coral and macroalgal habitats, with seascape effects playing a secondary role for some functional groups. Proximity to potential nursery habitats appeared to have minimal influence on coral reef fish assemblages. Consequently, coral, macroalgal, and mangrove habitats contained distinct fish assemblages that contributed to the overall diversity of fish within the seascape. Conclusions: Our findings underscore the importance of structural complexity for supporting diverse and abundant fish populations and suggest that the value of structural connectivity between habitats depends on local environmental context. Our results support management approaches that prioritise the preservation of habitat complexity, and that incorporate the full range of habitats comprising tropical seascapes. [ABSTRACT FROM AUTHOR]

Abstract Researchers often use surrogate species for assessing biodiversity—organisms that can indicate the presence of additional taxa or provide insight into environmental processes. As indicators of anthropogenic impact, “cross‐taxon” surrogates are theorized to be effective shortcuts for determining how communities respond to environmental change. However, few studies have implemented cross‐taxon surrogates given the challenge of validating the strength of the relationship between surrogates and their target taxa. Trophically transmitted parasites require multiple invertebrate and vertebrate taxa to complete their life cycles (e.g., annelids, mollusks, fishes, shorebirds), making them ideal cross‐taxon surrogates of community diversity. By sampling for these parasite surrogates, it is theoretically possible to infer the composition of the overall host community based on the species of parasites present. In our study, we tested the use of parasites as cross‐taxon surrogates of biodiversity by sampling for digenetic trematodes in the mudsnail Ilyanassa obsoleta, collected from coastal shoreline environments with or without artificial structures (e.g., bulkheads, seawalls). We found that trematode richness, evenness, and diversity were all greater in snails sampled from natural shorelines versus those with artificial structures. While parasite communities clustered by shoreline type (with vs. without artificial structures), we found no differences in multivariate dispersion, or beta‐diversity, between groups in our system. At the species level, trematodes requiring polychaetes and estuarine fishes as downstream hosts dominated parasite communities at shorelines with artificial structures. These taxa are ubiquitous but more abundant in degraded environments. In contrast, trematode species requiring mollusks and shorebirds as hosts was only documented from shorelines without artificial structures (i.e., natural), which may indicate that these areas are less degraded and have greater overall host diversity. High parasite diversity in easily collected hosts (e.g., mudsnails) provides evidence that the secondary (polychaetes, crustaceans) and tertiary (fishes, shorebirds) hosts required by the parasites are present in the system. Our study also helps validate the concept of surrogate species by demonstrating how a single species can represent broader taxonomic groups.

Abstract The interacting threats of invasive predators and altered fire regimes are key conservation issues for many native species globally. Artificial refuges have been proposed as a potential conservation tool to provide prey species with protection from invasive predators after fire, but we do not yet know whether they improve animal survival. To address this knowledge gap, we experimentally tested how small mammal abundance and species richness were influenced by the provision of artificial refuges after prescribed burns. We surveyed small mammals across five unburnt sites, seven burnt sites with artificial refuges, and eight burnt control sites following two prescribed fires in southeastern Australia. There were negative and neutral responses of small mammals to the burns, and relative abundance was positively correlated with structurally complex vegetation. Artificial refuges had no impact on abundance or species richness, irrespective of burn coverage. These findings suggest that this artificial refuge design may not be an effective tool for improving small mammal population persistence postfire, and as such we should not yet scale up their application. However, given the inherent context‐dependency of field experiments involving fire, which include difficult‐to‐control variables such as fire severity, predator activity, and population dynamics, we encourage researchers to undertake further experiments with artificial refuges in fire‐affected areas, including after severe wildfires when less vegetation cover remains. Such studies will help to build our understanding of their utility as a conservation tool across different ecosystems and fire types.

Abstract The health of coral reef benthic and fish communities is implicitly connected, yet typically studied and managed separately. By developing a coupled reef population model that connects coral populations and reef fish biomass through the habitat complexity that corals build and fish live among, we aim to address this gap by holistically quantifying ecological feedbacks and responses to ecological stressors. We explored the impacts of fishing effort in conjunction with three types of ecological disturbances as they propagated through a coral reef ecosystem: (1) a disturbance that disproportionately affected small, bio‐energetically vulnerable colonies, (2) a disturbance that predominantly affected large, mechanically vulnerable colonies, and (3) a disturbance that affected colonies of all sizes randomly. We found that joint coral and fish population recovery was fastest and most complete under events affecting small colonies, followed by recovery from disturbances affecting random sizes, and lastly large‐colony disturbances. These results suggest that the retention versus loss of large coral colonies with high reproductive potential critically influenced population recovery. Low fishing levels maintained fish and coral populations and allowed for recovery after disturbances, whereas high fishing levels prevented recovery due to greater fish‐dependent coral mortality. Finally, we tested various formulations of the relationship between coral size and habitat complexity (i.e., exponential, linear, logarithmic) that constrain fish carrying capacity. All formulations led to similar population projections in most disturbance scenarios, but there were exceptions where the timing and trajectory of recovery differed, such as faster and greater recovery potential when complexity is logarithmic with respect to coral size. These findings suggest that fishing and habitat complexity mediate the recovery of coral reef populations, emphasizing the importance of describing linkages between coral size distribution and reef habitat structure. Furthermore, our results highlight the utility of the coupled‐model framework for understanding and managing the impact of disturbances at ecosystem scales.

The composition, structure and distribution of vegetation are influenced by diverse environmental factors. Such research inquiries provide the initial data for future conservation and management efforts. The study area of North Waziristan district, Khyber Pakhtunkhwa, Pakistan comprises diverse forests of the Spin Ghar Mountain Range (at the border areas of Pakistan and Afghanistan), and a highly remote, mountainous, and unexplored region. There was little information on the complex relationships that existed between the study area's ambient environment and vegetation. This study hypothesized that the varying environmental complexity in the study area and vegetation variety may be significantly correlated, and the ranking of leading influencing factors might enhance our ecological understanding. A total of 61 study sites comprising 183 transects (50 m each) were randomly selected to record the vegetation-environment data from January-2018 to December-2020 (3 years). Monte Carlo permutation testing, hierarchical clustering of study samples, indicator species analysis, and ordination were applied to assess the sampling data. The results indicated that there were a total of 391 vascular plant species which were further classified into seven significantly different (p

The complexity of tropical reef habitats affects the occurrence and diversity of the organisms residing in these ecosystems. Quantifying this complexity is important to better understand and monitor reef community assemblages and their roles in providing ecological services. This study employed structure-from-motion photogrammetry to produce accurate 3D reconstructions of eight reefs in Guam and quantified the structural complexity of these sites using seven terrain metrics: rugosity, slope, vector ruggedness measure (VRM), multiscale roughness (magnitude and scale), plan curvature, and profile curvature. The relationships between terrain complexity, benthic community diversity, and coral cover were investigated with generalized linear models. While the average structural complexity metrics did not differ between most sites, there was significant variation within sites. All surveyed transects exhibited high structural complexity, with an average rugosity of 2.28 and an average slope of 43 degrees. Benthic diversity was significantly correlated with the roughness magnitude. Coral cover was significantly correlated with slope, roughness magnitude, and VRM. This study is among the first to employ this methodology in Guam and provides additional insight into the structural complexity of Guam's reefs, which can become an important component of holistic reef assessments in the future. [ABSTRACT FROM AUTHOR]

Ecosystem engineers are organisms that cause changes in the physical state of biotic and abiotic structures that modulate the availability of resources to other species, thus affecting biochemical cycles. Molluscs, especially bivalves such as mussels, are widespread in coastal environments and they are excellent ecosystem engineers because of the durability of their shells, which add complexity and heterogeneity to benthic environments. The presence of mussel farms favours the accumulation of shells in benthic environments and may influence surrounding bare sediments, with potential legacy effects on benthic communities. We studied the effects of the accumulation of mussel shells at finfish farms and mussel farms by experimentally comparing bare sediment and sediment with fragmented shells in terms of the abundance of the most relevant faunal groups, specifically polychaete families as well as physical–chemical variables in sediment water samples, specifically organic matter (OM), redox potential, and acid-volatile sulphides (AVS) NH4+ and PO43−. The experiment was replicated under two environmental conditions over a period of 35 days: eutrophic muddy sediments and oligotrophic sandy sediments. The OM and AVS values were significantly higher in the eutrophic sediment with mussel shells. Only NH4+ was positively affected by the mussel shells in the oligotrophic conditions. Differences between the two environments were observed, and the effect of the mussel shells on the polychaete assemblages was more significant in the oligotrophic conditions. Mussel shell accumulations affected the structure of benthic assemblages by modifying their heterogeneity and complexity, which suggests that the presence of mussel farms above bare sediment may affect ecosystem functioning. Aquaculture has potentially negative or positive effects that must be addressed on a large scale, considering the increased input of organic matter and also the simultaneous presence of mussel shell waste, both of which alter the surrounding environment. This is particularly important in oligotrophic sandy sediment. [ABSTRACT FROM AUTHOR]

Mass bleaching events and local anthropogenic influences have changed the benthic communities of many coral reefs with pronounced spatial differences that are linked to resilience patterns. The Gulf of Thailand is an under-investigated region with only few existing datasets containing long-term developments of coral reef communities using the same method at fixed sites. We thus analyzed benthic community data from seven reefs surrounding the island of Koh Phangan collected between 2014 and 2022. Findings revealed that the average live hard coral cover around Koh Phangan increased from 37% to 55% over the observation period, while turf algae cover decreased from 52% to 29%, indicating some recovery of local reefs. This corresponds to a mean increased rate of coral cover by 2.2% per year. The increase in live hard coral cover was mainly driven by plate-like corals, which quadrupled in proportion over the last decade from 7% to 28% while branching corals decreased in proportion from 9% to 2%. Furthermore, the hard coral genus richness increased, indicating an increased hard coral diversity. While in other reefs, increasing live hard coral cover is often attributed to fast-growing, branching coral species, considered more susceptible to bleaching and other disturbances, the reefs around Koh Phangan recovered mainly via growth of plate-like corals, particularly of the genus Montipora. Although plate-like morphologies are not necessarily more bleaching tolerant, they are important for supporting reef fish abundance and structural complexity on reefs, aiding reef recovery and sturdiness. Hence, our findings indicate that the intensity of local stressors around Kho Phangan allows reef recovery driven by some hard coral species. [ABSTRACT FROM AUTHOR]

Ecosystem engineers are organisms that cause changes in the physical state of biotic and abiotic structures that modulate the availability of resources to other species, thus affecting biochemical cycles. Molluscs, especially bivalves such as mussels, are widespread in coastal environments and they are excellent ecosystem engineers because of the durability of their shells, which add complexity and heterogeneity to benthic environments. The presence of mussel farms favours the accumulation of shells in benthic environments and may influence surrounding bare sediments, with potential legacy effects on benthic communities. We studied the effects of the accumulation of mussel shells at finfish farms and mussel farms by experimentally comparing bare sediment and sediment with fragmented shells in terms of the abundance of the most relevant faunal groups, specifically polychaete families as well as physical–chemical variables in sediment water samples, specifically organic matter (OM), redox potential, and acid-volatile sulphides (AVS) NH4+ and PO43−. The experiment was replicated under two environmental conditions over a period of 35 days: eutrophic muddy sediments and oligotrophic sandy sediments. The OM and AVS values were significantly higher in the eutrophic sediment with mussel shells. Only NH4+ was positively affected by the mussel shells in the oligotrophic conditions. Differences between the two environments were observed, and the effect of the mussel shells on the polychaete assemblages was more significant in the oligotrophic conditions. Mussel shell accumulations affected the structure of benthic assemblages by modifying their heterogeneity and complexity, which suggests that the presence of mussel farms above bare sediment may affect ecosystem functioning. Aquaculture has potentially negative or positive effects that must be addressed on a large scale, considering the increased input of organic matter and also the simultaneous presence of mussel shell waste, both of which alter the surrounding environment. This is particularly important in oligotrophic sandy sediment.

The long-term sustainability of ex situ animal populations requires coordination across facilities through cooperative breeding programs. Here, we investigate the reasons for inconsistent reproductive success in the zoo-based North American Asian small-clawed otter (ASCO; Aonyx cinereus) population. Reproductive viability analysis (RVA) was used to identify which characteristics of ASCOs in breeding pairs were most predictive of reproductive success. The RVA identified pair type, contraception history, and age as the most significant predictors of offspring production. The use of deslorelin in males and long-term deslorelin use in females hinder future reproductive potential and should, therefore, be considered carefully in genetically valuable individuals and potential breeders. Moreover, genetically valuable animals should be paired with younger mates, as advancing male and female age decreases the likelihood of success. The lack of reproductive success observed after 1 year of attempted breeding among new pairs provides evidence of potential mate incompatibility, therefore, population managers should consider splitting up pairs that remain unsuccessful over time, because the likelihood of offspring production is low. Lastly, the inclusion of dens and/or caves and pools designed with ample shallow water areas in ASCO habitats may improve breeding success.

Numerous sampling methods have been applied to study intertidal rock pool fishes. There is limited information comparing the performance and suitability of such methods, which complicates comparisons between studies. We compared the performance of the bailing and visual census methods in 10 rock pools to quantify abundance, species richness, and structure of fish assemblages in rock pool intertidal systems considering fish residency affinities, rock pool volume, and substratum rugosity. Sampling was conducted 13 times across the complete set of 10 rock pools from June to December, 2018. Each of the pools was sampled with a visual census and then the bailing method. A sampling event was defined as the process of conducting both a visual and a bailing survey in a single rock pool. In total, 1,749 individuals of 14 species were detected using the bailing method, whereas 438 individuals of 8 species were recorded via visual census. The bailing method yielded higher abundance and species richness of resident, opportunist, and transient fish than the visual census. The detection of individuals and species showed a positive association with rock pool volume and negative association with substratum rugosity for both methods. In 32 sampling events, the bailing method detected fish correcting reports of fish absence (false negatives) recorded with the visual census. For the bailing method, resident fishes dominated the fish assemblage, whereas, for the visual census, resident and opportunist fishes contributed similarly to the community.

Mass bleaching events and local anthropogenic influences have changed the benthic communities of many coral reefs with pronounced spatial differences that are linked to resilience patterns. The Gulf of Thailand is an under-investigated region with only few existing datasets containing long-term developments of coral reef communities using the same method at fixed sites. We thus analyzed benthic community data from seven reefs surrounding the island of Koh Phangan collected between 2014 and 2022. Findings revealed that the average live hard coral cover around Koh Phangan increased from 37% to 55% over the observation period, while turf algae cover decreased from 52% to 29%, indicating some recovery of local reefs. This corresponds to a mean increased rate of coral cover by 2.2% per year. The increase in live hard coral cover was mainly driven by plate-like corals, which quadrupled in proportion over the last decade from 7% to 28% while branching corals decreased in proportion from 9% to 2%. Furthermore, the hard coral genus richness increased, indicating an increased hard coral diversity. While in other reefs, increasing live hard coral cover is often attributed to fast-growing, branching coral species, considered more susceptible to bleaching and other disturbances, the reefs around Koh Phangan recovered mainly via growth of plate-like corals, particularly of the genus Montipora. Although plate-like morphologies are not necessarily more bleaching tolerant, they are important for supporting reef fish abundance and structural complexity on reefs, aiding reef recovery and sturdiness. Hence, our findings indicate that the intensity of local stressors around Kho Phangan allows reef recovery driven by some hard coral species.

Understanding the elevational variation in species richness and community composition as well as their mechanisms is critical for biodiversity conservation. On Mt Jianfengling of China, we examined the elevational patterns of species richness and analyzed the important variables driving the variation of species richness and community composition using boosted regression trees for all mosses and two growth forms and three life forms of mosses, respectively. We assessed the contribution of elevation toward explaining the heterogeneity among sampling sites. Last, we compared the occurrence probability and proportional use of community type along the elevational gradient between two growth forms and three life forms of mosses. Although each taxonomic group displayed a negatively skewed (hump-shaped) diversity pattern and a high turnover rate of community composition along the elevational gradient, the leading drivers for the patterns of each group are different. The habitat complexity and the mid-domain effect (MDE) hypothesis were supported for the diversity patterns of acrocarpous mosses and turfs, whereas the habitat complexity hypothesis was supported for pleurocarpous mosses, mats, and wefts. Habitat composition dominated the community variation of acrocarpous mosses and turfs, whereas solar radiation was the leading factor for pleurocarpous mosses, mats and wefts. According to the additive diversity partitioning, α explained only 4.8–7.3% of the variation in species richness. For many low-lying sampling sites with sunny and dry conditions, extinction and dispersal limitation might be the primary processes producing low species richness pattern, which decreases the overall average diversity for each group. The variations of the occurrence probability and proportional use of community type along the elevational gradient in each group explain the contributions of elevation toward the heterogeneity among sampling sites for all mosses. With higher sensitivity to environmental changes, pleurocarpous mosses and wefts may have greater fluctuations in species richness when environmental conditions turn from unfavorable to optimal, therefore the elevation effect on explaining the heterogeneity among sampling sites was higher (18.9%) for pleurocarpous mosses as compared to 11.1% for acrocarpous mosses; and it ranged from a low of 11.0% in turfs to 19.9% in wefts. Although each group displayed similar biogeographic patterns along the elevational gradient, the underlying drivers are different. Therefore, the total measurements of species will veil the complex mechanisms for each growth form and life form. It is also suggested that conservation efforts should be paid to the top altitude for pleurocarpous mosses, mats and wefts, and the whole elevational range for acrocarpous mosses and turfs.

Coral reefs are highly biodiverse ecosystems that have declined due to natural and anthropogenic stressors. Researchers often attribute reef ecological processes to corals' complex structure, but effective conservation requires disentangling the contributions of coral versus reef structures. Many studies assessing the relationships between reef structure and ecological dynamics commonly use live coral as a proxy for reef complexity, disregarding the contribution of dead coral skeletons to reef habitat provision or other biogeochemical reef dynamics. This study aimed to assess the contribution of dead coral to reef complexity by examining structural variations in live and dead Acropora palmata colonies. We used photogrammetry to reconstruct digital elevation models (DEMs) and orthomosaics of the benthic region immediately surrounding 10 A. palmata colonies. These reconstructions were used to quantify structural metrics, including surface rugosity, fractal dimension, slope, planform curvature, and profile curvature, as a function of benthic composition (i.e., live A. palmata, dead A. palmata, or non-A. palmata substrate). The results revealed that dead coral maintained more varied profile curvatures and higher fractal dimensions than live or non-coral substrate. Conversely, A. palmata colonies with a higher proportion of live coral displayed more uniform structure, with lower fractal dimensions and less variability in profile curvature measures. Other metrics showed no significant difference among substrate types. These findings provide novel insights into the structural differences between live and dead coral, and an alternative perspective on the mechanisms driving the observed structural complexity on reefs. Overall, our results highlight the overlooked potential contributions of dead coral to reef habitat provision, ecological processes, and other biogeochemical reef dynamics, and could have important implications for coral reef conservation. [ABSTRACT FROM AUTHOR]

In social animals, success can depend on the outcome of group battles. Theoretical models of warfare predict that group fighting ability is proportional to two key factors: the strength of each soldier in the group and group size. The relative importance of these factors is predicted to vary across environments [F. W. Lanchester, Aircraft in Warfare, the Dawn of the Fourth Arm (1916)]. Here, we provide an empirical validation of the theoretical prediction that open environments should favor superior numbers, whereas complex environments should favor stronger soldiers [R. N. Franks, L. W. Partridge, Anim. Behav. 45, 197-199 (1993)]. We first demonstrate this pattern using simulated battles between relatively strong and weak soldiers in a computer-driven algorithm. We then validate this result in real animals using an ant model system: In battles in which the number of strong native meat ant Iridomyrmex purpureus workers is constant while the number of weak non-native invasive Argentine ant Linepithema humile workers increases across treatments, fatalities of I. purpureus are lower in complex than in simple arenas. Our results provide controlled experimental evidence that investing in stronger soldiers is more effective in complex environments. This is a significant advance in the empirical study of nonhuman warfare and is important for understanding the competitive balance among native and non-native invasive ant species. [ABSTRACT FROM AUTHOR]

The long-term sustainability of ex situ animal populations requires coordination across facilities through cooperative breeding programs. Here, we investigate the reasons for inconsistent reproductive success in the zoo-based North American Asian small-clawed otter (ASCO; Aonyx cinereus) population. Reproductive viability analysis (RVA) was used to identify which characteristics of ASCOs in breeding pairs were most predictive of reproductive success. The RVA identified pair type, contraception history, and age as the most significant predictors of offspring production. The use of deslorelin in males and long-term deslorelin use in females hinder future reproductive potential and should, therefore, be considered carefully in genetically valuable individuals and potential breeders. Moreover, genetically valuable animals should be paired with younger mates, as advancing male and female age decreases the likelihood of success. The lack of reproductive success observed after 1 year of attempted breeding among new pairs provides evidence of potential mate incompatibility, therefore, population managers should consider splitting up pairs that remain unsuccessful over time, because the likelihood of offspring production is low. Lastly, the inclusion of dens and/or caves and pools designed with ample shallow water areas in ASCO habitats may improve breeding success. [ABSTRACT FROM AUTHOR]

In response to uncertain risks, prey may rely on neophobic phenotypes to reduce the costs associated with the lack of information regarding local conditions. Neophobia has been shown to be driven by information reliability, ambient risk and predator diversity, all of which shape uncertainty of risk. We similarly expect environmental conditions to shape uncertainty by interfering with information availability. In order to test how environmental variables might shape neophobic responses in Trinidadian guppies (Poecilia reticulata), we conducted an in situ field experiment of two high‐predation risk guppy populations designed to determine how the 'average' and 'variance' of several environmental factors might influence the neophobic response to novel predator models and/or novel foraging patches. Our results suggest neophobia is shaped by water velocity, microhabitat complexity, pool width and depth, as well as substrate diversity and heterogeneity. Moreover, we found differential effects of the 'average' and 'variance' environmental variables on food‐ and predator‐related neophobia. Our study highlights that assessment of neophobic drivers should consider predation risk, various microhabitat conditions and neophobia being tested. Neophobic phenotypes are expected to increase the probability of prey survival and reproductive success (i.e. fitness), and are therefore likely linked to population health and species survival. Understanding the drivers and consequences of uncertainty of risk is an increasingly pressing issue, as ecological uncertainty increases with the combined effects of climate change, anthropogenic disturbances and invasive species. [ABSTRACT FROM AUTHOR]

Remote sensing technology offers the ability to derive information on freshwater fish habitats across broad geographic areas and has the potential to transform approaches to monitoring. However, the numerous platforms, sensors and analytical software that are available may overwhelm those interested in utilizing this important technology and thus limit its broad application and uptake. Our review is intended to shed light on the capacity of this technology to transform freshwater fish habitat monitoring by examining the fundamental characteristics of the major remote sensing technologies that have been used for characterizing freshwater habitats, conducting a systematic literature review of studies that have used remote sensing technologies to characterize freshwater fish habitats and, highlighting some of the key habitat features, fish species and regions, that have been examined. Lastly, we identify the relative strengths and weaknesses of the various remote sensing technologies that can be used, recommend future research that could help improve the use of these technologies, and, provide a series of important considerations for those who are interested in utilizing these technologies for freshwater fish habitat characterization. [ABSTRACT FROM AUTHOR]

Habitat type and grazing are key factors controlling benthic diatom communities. Nonetheless, the strength of grazing may depend on the habitat complexity at fine (substratum roughness) and meso scales (mesohabitat type). The interaction between grazers and physical conditions may thus be an important factor shaping benthic diatom communities. Several investigations have evaluated how habitat type, grazing and substratum roughness separately affect the biomass, species richness and community structure of algal communities. However, how these factors act together remains poorly understood, particularly for sets of common and rare species. The latter is important for understanding whether common and rare species are affected differently by environmental filters at the local scale.We investigated the effects of mesohabitat type, grazer occurrence and substratum roughness as well as their interactions on benthic diatom communities in a split‐split‐plot field experiment consisting of hierarchical treatments: (i) mesohabitat (pools and riffles); (ii) grazer occurrence (presence or absence of grazers >1 cm in size); and (iii) substratum roughness (smooth and rough substrata). We analysed the entire community and also datasets of common and rare species. Here, we define common and rare species based on their abundance–occupancy relationships, with rare species presenting low mean abundance per experimental unit (between 0.025 and 8.2) and low occupancy (between 2.5% and 25%).Substratum roughness was the main factor explaining differences in species richness, with higher species richness found on rough than on smooth substrata for both the complete dataset and for common and rare species. There was evidence that the interactions between mesohabitat and grazer occurrence and between mesohabitat and substratum roughness affected community structure (relative abundances) for the complete dataset and for common species, whereas the three‐way interaction between mesohabitat, grazer and substratum roughness affected community structure of rare species.Our findings emphasise that crevices are important microhabitats that allow the establishment of both common and rare species. Furthermore, our results suggest that physical differences between mesohabitats influenced the effect of grazers on the community structure of common and rare species. For common species, the effects of this interaction were difficult to depict, but we found a change in the second‐most‐common species between mesohabitats and depending on the occurrence of grazers. For rare species, grazers more clearly affected community structure on smooth substrata in riffles than in pools.Our results demonstrate that local patterns of common and rare diatom species resulted from distinct combinations of the evaluated environmental filters. Together, our results highlight how multifactorial field experiments are key to understanding the main environmental filters driving the species richness and community structure of benthic diatom communities. [ABSTRACT FROM AUTHOR]

Coral reef habitat quality is declining in many locations because of heatwaves (coral bleaching) and other disturbances. Reef‐building corals provide refuge from predation, so declining complexity restricts the transfer of energy to upper trophic levels.We use a size‐based ecosystem model to test systematically the effects of refuge at specific sizes and the impacts of distributions of refuges that vary in size. Outcomes are assessed in terms of ecosystem service provision.Simulations indicate that refuge sheltering fish between 5 and 10 cm in length enhances fish biomass and fisheries productivity, for example, increasing herbivore biomass by up to 80%.We identify and present a range of refuge profiles that can theoretically improve ecosystem service provision by as much as sixfold. Profiles where refuge availability decreases with increasing fish size consistently outrank other designs.Synthesis and application: These results highlight how critical small‐scale refuge is for coral reefs, and how we might design artificial reefs to maximise service provision. [ABSTRACT FROM AUTHOR]

Polychaetes play a vital role in the structure and functioning of benthic communities in mangrove ecosystems. Nevertheless, our understanding of the diversity and functional structure of polychaete assemblages across different habitats in the mangrove ecosystems along the coast of the Persian Gulf and Gulf of Oman is limited. In this study, we investigated the species and trait composition of polychaetes and environmental variables, in vegetated and mudflat habitats of three subtropical mangroves. The results showed that Neanthes glandicincta was widely distributed across all regions and habitats. The three-factor ANOVA showed that the abundance and taxonomic diversity of polychaetes differed significantly between two habitats and three mangrove ecosystems. The abundance of polychaetes was observed to be higher in mud habitats than in vegetated habitats. There was a significant difference in species and trait composition between different regions and habitats. Vegetated habitats had higher proportions of crawler predatory species that are longer lived (3–5 years), with larger body size (80–100 mm), and are upward conveyors, whereas mudflat habitats had higher proportions of mobile (burrower) omnivore species that are moderately lived (1–3 years), with larger body size (>100 mm), and are biodiffusers. The three-factor ANOVA showed a significant difference in the community weighted mean (CWM) index between two habitats and three mangrove ecosystems. Thus, the species and trait composition of polychaetes depend on the structural complexity of their respective habitats. The DistLM analysis showed that total organic carbon content of the sediment was the main predictor variable influencing species composition, while silt/clay content and salinity were the main predictor variables influencing the traits' composition. The results showed how the composition of traits and the structure of polychaete communities change in mangrove ecosystems, which can be used for future studies on conservation strategies for mangrove ecosystems throughout the world. [ABSTRACT FROM AUTHOR]

Matern S, Robichon C, Nikolaus R, Monk CT, Arlinghaus R. 2023. Environmental determinants of coarse woody habitat in gravel pit lakes. Lake Reserv Manage. 39:259–272. Coarse woody habitat (CWH) is an important structural habitat in freshwater ecosystems. In natural lakes, CWH accumulates over centuries alongside the succession of littoral tree communities. Newly created gravel pit lakes have difficulties in accumulating CWH due to their young age. Additionally, CWH presence might be negatively affected by shoreline development, where wood is removed to facilitate recreational activities such as angling. We studied 26 gravel pit lakes with an age ≤ 55 yrs in Lower Saxony, Germany, to quantify CWH density and to understand the impact of environmental factors, including lake morphology, lake age, wind direction, abundance of riparian trees, and the presence or absence of fisheries management, on CWH density. We sampled small and large CWH in the littoral zone of the study lakes using a transect-based approach. Density of CWH was lower in German gravel pit lakes than in North American natural lakes. In gravel pit lakes, we detected increasing densities of small CWH with increasing numbers of large trees on the shore and with increasing littoral slopes in lakes managed for recreational fisheries. Large CWH density was positively affected by lake age, by the density of large trees on the shore and with wind from land, and again by steep littoral slopes in lakes managed for recreational fisheries. We recommend that recreational fisheries managers and individual anglers maintain CWH in shallow littoral zones to promote fish habitats in generally low-structured gravel pit lakes. [ABSTRACT FROM AUTHOR]

An organism’s habitat preference may shift to one of greater structural complexity to maximize protection from predatory attack. In south-eastern Australian coastal seascape, seagrass beds, sandy substratum and/or rocky algal reef border each other forming a matrix of varying habitat configurations with varying protection potential. We investigated the change in habitat selection in four Australian seagrass fish species, Stigmatopora argus, Acanthaluteres spilomelanurus, Pelates sexlineatus and Atherinosoma microstomata with the inclusion of predatory threat using tank experiments. The 250L, 90 cm internal diameter experimental tank contained three habitats – seagrass, sand and rock arranged in an unbroken circular path creating three distinct edge combinations and resulting in six sections of varying levels of complexity and heterogeneity. A transparent inner wall separated the habitat matrix from the central test chamber, which contained and demarcated “zone of decision”. Each test fish (n=123) was placed in the tank centre for 2–3 minutes in an isolation tube to acclimatize before being released to make its selection. This was repeated for each test fish first without predatory threat then with threat. S. argus spent significantly more time in the rock section (paired t-test: p= 0.038) and less time in the seagrass-sand section (paired t-test: p=0.05) when under threat. A. spilomelanurus spent significantly less time in homogeneous seagrass when threatened (paired t-test: p = 0.016) and displayed a non-significant increased selection of sections containing rock when threatened. Shifts to the complex rocky substratum preference with predatory threat was demonstrated along with the importance of a suite of different habitats for a species’ survival. [ABSTRACT FROM AUTHOR]

Acoustic communication is vital to the survival and fitness of many vertebrates. While successful communication is reliant on acoustic signals reaching an intended receiver and maintaining content fidelity, propagating signals are attenuated by environmental factors such as habitat type. The acoustic adaptation hypothesis (AAH) predicts that the acoustic properties of signals are selected for optimal transmission in the habitats in which they propagate. To date, consistent evidence to support the theory is lacking, but studies have typically been primarily based on localized datasets with small sample sizes. Citizen science is emerging as a potential means to overcome the challenges associated with broad‐scale sampling, allowing us to assess the validity of the AAH in frogs on a continental scale. We analysed the male advertisement calls of 674 individual banjo frogs (Limnodynastes dorsalis, L. dumerilii, L. interioris and L. terraereginae) from across their range, pairing these citizen science data with remotely sensed measures of habitat complexity. While we detected considerable variation in acoustic structure within and among banjo frog species, this was not strongly correlated with habitat complexity. Thus, we found no support for the AAH. However, with our study spanning an area of over 1.7 million km2, we conducted the largest‐scale test of the AAH in frogs to date, contributing to the global understanding of acoustic signal evolution. [ABSTRACT FROM AUTHOR]

Declines in habitat structural complexity have marked ecological outcomes, as currently observed in many of the world's ecosystems. Coral reefs have provided a model for such changes in marine ecosystems; still our understanding has been centered on corals and fishes at broad spatial scales when metazoan diversity on coral reefs is dominated by small cryptic taxa (herein: "cryptofauna"). Given the paucity of studies and high taxonomic complexity of the cryptofauna, both of which limit a priori hypotheses, we asked whether hierarchical structuring theory provides a compelling framework to impose order and quantify patterns. In general terms, we explored whether cryptic communities are sufficiently described by broad seascape parameters or limited by a set of processes operating at their distinctly nested microhabitat scale. To address this theory and gaps in knowledge for the cryptofauna, we characterized community structure in coral rubble, an eroded coral condition where biodiversity proliferates. Rubble was sampled along a depth and exposure gradient at Heron Island on the Great Barrier Reef, Australia, to parameterize environmental and morphological indicators of sessile taxa and motile cryptofauna communities. We used a hierarchical study framework from microhabitat to seascape scales, which were evaluated using nonstructured multivariate analyses and Bayesian structural equation modeling. While the nonstructured analyses showed the effects of seascape on the cryptobenthos and its community, this approach overlooked the finer hierarchical patterns in rubble ecology revealed only in the structured model. Seascape parameters (exposure and depth) influenced microhabitat complexity (i.e., rubble branchiness), which determined the cover of sessile organisms on rubble pieces, which shaped the motile cryptofauna community. Rubble is likely to be increasingly prevalent on coral reefs in the Anthropocene and is typically associated with low seascape‐level complexity and reduced macrofaunal richness. Parallel with hierarchical structuring theory, we showed a similar response operating at the microhabitat scale whereby low rubble complexity (i.e., branchiness) reduced cryptobenthic structure, diversity and size spectra. In a future ocean, we expect there may be an initial increase in biodiversity and trophodynamic processes derived from branching rubble, but a delay in ecosystem‐scale outcomes if coral, and thus rubble, generation and complexity is not sustained. [ABSTRACT FROM AUTHOR]

Community assembly theory hypothesizes that two main niche-based processes act to shape composition and organization of biological assemblages: abiotic filtering and biological interactions. Here, we conducted repeated surveys of bird abundance along an undisturbed elevational gradient in the tropical Andes to investigate 1) signals of deterministic processes driving community assembly and 2) potential mechanisms by which these forces operate (temperature, habitat complexity, fruit and insect availability), while correcting for imperfect detection and modeling species abundances with N-mixture models. We observed strong signals of abiotic filtering driving functionally and phylogenetically clustered assemblages towards higher elevations, and a weaker signal of limiting similarity resulting in few overdispersed assemblages at lower elevations. Whereas the decay in species richness with increasing elevation was explained by temperature, trait and phylogenetic dispersion were explained by both temperature and vegetation structure, implying that an interplay of abiotic and biotic mechanisms determines abundance-based community structure in our montane assemblages. Interestingly, trait and phylogenetic dispersion consistently decreased until ~3000 m but increased above this elevation, highlighting a potential role of competition in resource-scarce habitats. Combined, our findings suggest abiotic filters are still the main process shaping montane biotas across elevations, whereas resource availability might act locally upon assemblages further modifying them. Our study challenges recent studies in tropical mountains that suggest that biotic filters are a stronger force than abiotic filters in shaping tropical montane assemblages, and exemplifies how accounting for imperfect detection might overcome potential biases in detecting environmental filtering signals in community assembly studies.