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Multi‐trophic diversity is often overlooked in land management decisions due to the absence of cost‐ and time‐effective assessment methods. Here, we introduce a new method to calculate a combined terrain and canopy structural complexity metric using LiDAR data, enabling the prediction of multi‐trophic diversity—a combined diversity metric that integrates diversity across trophic levels. We selected 34 forested sites of the National Ecological Observatory Network to test the model by using observed data on plant presence, beetle pitfall trap, and bird count to calculate multi‐trophic diversity. Our results show that multi‐trophic diversity increases with increasing structural complexity, but this relationship differs across different forest types. The environmental and geographic factors account for about 40% variability in multi‐trophic diversity, which further increases to about 60% when combined with structural complexity. This research offers a powerful approach to evaluate biodiversity at a landscape scale using remotely sensed data and highlights the importance of considering multi‐trophic diversity in land management decisions.

The “area–heterogeneity tradeoff” hypothesis predicts unimodal effects of habitat heterogeneity on species richness, implying that habitats with intermediate heterogeneity may be priority for spatial protection. Alternatively, if heterogeneity effects are positive, then protecting the most heterogeneous habitats may take precedence. We tested for unimodal effects of habitat heterogeneity on the species density (area‐corrected richness) of rockfishes (Sebastes spp.): long‐lived, benthic fishes vulnerable to overexploitation. Inconsistent with predictions, topographic structural complexity had a strong linear effect on species density; other heterogeneity measures had weaker, positive effects and the only unimodal effect (depth range) was weak. The clear implication is that, to protect the highest density of rockfish species, marine protected areas should include the most topographically complex substrates. Our results can also help refine and test species distribution models needed to inform spatial planning where in situ surveys are lacking. The area–heterogeneity tradeoff generates useful predictions for which support may be context‐dependent.

With the demand for, and scale of, ecological restoration increasing globally, effectiveness monitoring remains a significant challenge. For forest restoration, structural complexity is a recognised indicator of ecosystem biodiversity and in turn a surrogate for restoration effectiveness. Structural complexity captures the diversity in vegetation elements, from tree height to species composition, and the layering of these elements is critical for dependent organisms which rely upon them for their survival. Traditional methods of measuring structural complexity are costly and time-consuming, resulting in a discrepancy between the scales of ‘available’ versus ‘needed’ information. With advancements in both sensors and platforms, there exists an unprecedented opportunity for landscape-level effectiveness monitoring using remote sensing. We here review the key literature on passive (e.g., optical) and active (e.g., LiDAR) sensors and their available platforms (spaceborne to unmanned aerial vehicles) used to capture structural attributes at the tree- and stand-level relevant for effectiveness monitoring. Good cross-validation between remotely sensed and ground truthed data has been shown for many traditional attributes, but remote sensing offers opportunities for assessment of novel or difficult to measure attributes. While there are examples of the application of such technologies in forestry and conservation ecology, there are few reports of remote sensing for monitoring the effectiveness of ecological restoration actions in reversing land degradation. Such monitoring requires baseline data for the restoration site as well as benchmarking the trajectory of remediation against the structural complexity of a reference system.

Structural properties including hierarchies have been recognised as important factors influencing quality of a software product. Metrics based on structural properties (structural complexity metrics) have been popularly used to assess the quality attributes like understandability, maintainability, fault-proneness etc. of a software artefact. Although few researchers have considered metrics based on dimension hierarchies to assess the quality of multidimensional models for data warehouse, there are certain aspects of dimension hierarchies like those related to multiple hierarchies, shared dimension hierarchies among various dimensions etc. which have not been considered in the earlier works. In the authors’ previous work, they identified the metrics based on these aspects which may contribute towards the structural complexity and in turn the quality of multidimensional models for data warehouse. However, the work lacks theoretical and empirical validation of the proposed metrics and any metric proposal is acceptable in practice, if it is theoretically and empirically valid. In this study, the authors provide thorough validation of the metrics considered in their previous work. The metrics have been validated theoretically on the basis of Briand's framework – a property-based framework and empirically on the basis of controlled experiment using statistical techniques like correlation and linear regression. The results of these validations indicate that these metrics are either size or length measure and hence, contribute significantly towards structural complexity of multidimensional models and have considerable impact on understandability of these models.

Fine-scale structural complexity created by reef-building coral in shallow-water environments is influential on biodiversity, species assemblage and functional trait expression. Cold-water coral reefs are also hotspots of biodiversity, often attributed to the hard surface and structural complexity provided by the coral. However, that complexity has seldom been quantified on a centimetric scale in cold-water coral reefs, unlike their shallow-water counterparts, and has therefore never been linked in a similar way to the reef inhabitant community. Structure from motion techniques which create high-resolution 3D models of habitats from sequences of photographs is being increasingly utilised, in tandem with 3D spatial analysis to create useful 3D metrics, such as rugosity. Here, we demonstrate the use of ROV video transect data for 3D reconstructions of cold-water coral reefs at depths of nearly 1000 m in the Explorer Canyon, a tributary of Whittard Canyon, NE Atlantic. We constructed 40 3D models of approximately 25-m-length video transects using Agisoft Photoscan software, resulting in sub-centimetre resolution reconstructions. Digital elevation models were utilised to derive rugosity metrics, and orthomosaics were used for coral coverage assessment. We found rugosity values comparable to shallow-water tropical coral reef rugosity. Reef and nearby non-reef communities differed in assemblage composition, which was driven by depth and rugosity. Species richness, epifauna abundance and fish abundance increased with structural complexity, being attributed to an increase in niches, food, shelter and alteration of physical water movement. Biodiversity plateaued at higher rugosity, illustrating the establishment of a specific reef community supported by more than 30% coral cover. The proportion of dead coral to live coral had limited influence on the community structure; instead, within-reef patterns were explained by depth and rugosity, though our results were confounded to a certain extent by multi-collinearity. Fine-scale structural complexity appeared to be integral to local-scale ecological patterns in cold-water coral reef communities.

1. In response to multiple Stressors, coral reef health has declined in recent decades, with reefs exhibiting reduced living coral and structural complexity, and a concomitant rise in the dominance of algal resources. Reef degradation alters food availability and reduces the diversity and density of refuges for prey. These changes affect predator-prey interactions and can have cascading impacts on food webs and fisheries productivity. 2. We use a size-based ecosystem model of coral reefs that incorporates the influence of structural complexity, benthic primary production and detrital recycling to explore how predator-prey interactions and fisheries productivity respond to a gradient of reef degradation. 3. We show that fisheries productivity overall may be robust to initial stages of reef degradation because the benefits of increased resources outweigh the costs of moderate refuge decline. However, the assemblage composition and size structure of reef fish will differ on degraded reefs, with herbivores and invertivores contributing relatively more to productivity. 4. More significant losses of refuges associated with the erosion of structural complexity correspond to fisheries productivity losses of at least 35% compared to healthy reefs. 5. Synthesis and applications. Our model provides fisheries managers with quantitative predictions about how fisheries productivity may change in response to the ongoing degradation of coral reefs. We predict an initial increase in productivity at intermediate reef degradation, followed by a drastic decline when structural complexity is lost. We also capture subtle changes to potential catch composition and fish size, including increases in smaller herbivorous and invertivorous fish from degraded reefs, which will undoubtedly impact fisheries value. On the one hand, our results reassure for continued productivity in the short term, but on the other, we warn against complacency. Management must change to capture any potential benefits to fisheries, and long-term sustainability still depends on the maintenance of complex coral reef habitats.

Habitat complexity is one of the most important factors structuring biotic assemblages, yet we still lack basic understanding of the underlying mechanisms. Although it is one of the primary targets in conservation management, no methods are available for comparing complexity across ecosystems, and system-specific qualitative assessment predominates. Despite its overwhelming importance for faunal diversity and abundance, there has been surprisingly little interest in examining its effects on other community and ecosystem attributes. We discuss possibilities of such effects, outlining potentially fruitful areas for future research, and argue that complexity may be implicated in community persistence and ecosystem stability by acting as a decoupling mechanism in predator–prey interactions. We provide a brief overview of methods used to quantify complexity in different ecosystems, highlighting contributions of the current issue of Hydrobiologia, and discuss potential application of these approaches for cross-ecosystem comparisons. Better understanding of the role of habitat complexity resulting from such comparisons is critically important for preservation of biodiversity and ecosystem function in an era of unprecedented habitat loss.

Purpose - The purpose of this paper is to contribute to operations management (OM) practice contingency research by describing the complexity of projects. Complexity is recognised as a key independent (contingent) variable that impacts on many subsequent decisions in the practice of managing projects.Design methodology approach - This paper presents a systematic review of relevant literature and synthesises an integrated framework for assessing the complexities of managing projects.Findings - This framework comprises five dimensions of complexity - structural, uncertainty, dynamics, pace and socio-political complexity. These five dimensions present individuals and organisations with choices about how they respond to each type of complexity, in terms of business case, strategic choice, process choice, managerial capacity and competencies.Originality value - The contribution of this paper is to provide a clarification to the epistemology of complexity, to demonstrate complexity as a lived experience for project managers, and offer a common language for both practitioners and future empirical studies considering the individual or organisational response to project complexities. The work also demonstrates an application of systematic review in OM research.

• An abrupt transition in the fossil record separates Early Devonian euphyllophytes with a simple structure from a broad diversity of structurally complex Middle–Late Devonian plants. Morphological evolution and phylogeny across this transition are poorly understood due to incomplete sampling of the fossil record. We document a new Early Devonian radiatopsid and integrate it in analyses addressing euphyllophyte relationships. • Anatomically preserved Emsian fossils (402–394 Ma) from the Battery Point Formation (Gaspé, Quebec, Canada) are studied in serial sections. The phylogenetic analysis is based on a matrix of 31 taxa and 50 characters emphasising vegetative morphology (41 discrete, nine continuous). • The new plant, Kenrickia bivena gen. et sp. nov., is one of very few structurally complex euphyllophytes documented in the Early Devonian. Inclusion of Kenrickia overturns previously established phylogenetic relationships among Radiatopses, reiterating the need for increased density of Early Devonian taxon sampling. Kenrickia is recovered as the sister lineage to all other radiatopsids, a clade in which paraphyletic Stenokoleales led to a lignophyte clade where archaeopterids and seed plants fall into sister clades. • Our results shed light on early euphyllophyte relationships and evolution, indicating early exploration of structural complexity by multiple lineages and reiterating the potential of a single origin of secondary growth in euphyllophytes.