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Niche construction refers to the modification of selective environments by organisms. Theoretical and empirical studies of niche construction are increasing in importance as foci in evolutionary ecology. This special edition presents theoretical and empirical research that illustrates the significance of niche construction to the field. Here we set the scene for the following papers by (1) discussing the history of niche construction research, (2) providing clear definitions that distinguish niche construction from related concepts such as ecosystem engineering and the extended phenotype, (3) providing a brief summary of the findings of niche construction research, (4) discussing the contribution of niche construction and ecological inheritance to (a) expanded notions of inheritance, and (b) the extended evolutionary synthesis, and (5) briefly touching on some of the issues that underlie the controversies over niche construction. [ABSTRACT FROM AUTHOR]

Plants can slow water and trap sediment with their canopies and stabilise sediment with their roots. These influences are mediated by the characteristics or traits of the vegetation. Here, we review and investigate the flexibility, size, root form, clonal growth, perennation and Ellenberg F values of 459 European riverine species, considering their role in physical and ecological processes. We make use of existing plant trait datasets to create two typologies: one that identifies the role vegetation has in channel blockage (conveyance) and sediment accrual and a second typology, that indicates vegetation's ability to stabilize sediment. The two typologies are tools for interpreting botanical survey data collected using standard techniques across large numbers of sites as part of the European Union Water Framework Directive monitoring programmes. As such, they are designed to be used to indicate broad-scale patterns across sites rather than detailed insights into site-specific processes. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The fossil record of deep-marine environments is notoriously poor in comparison with that of their shallow-marine counterparts. Notably, deep-marine deposits are typically host to diverse and abundant trace-fossil assemblages, providing evidence of the ancient deep-sea benthos. To analyze the early colonization of the deep sea, we constructed a global dataset of trace-fossil occurrences from a survey of Ediacaran–Devonian stratigraphic units. This analysis highlights the importance of the Ordovician radiation as a pivotal time in the colonization of the deep sea. Ediacaran deep-marine trace fossils consist of very simple trails and burrows. Global and alpha ichnodiversity, as well as ichnodisparity, were extremely low. Nonspecialized grazing trails reveal the exploitation of microbial mats. These strategies persisted in the Cambrian, although with an increase in ichnodiversity (both global and alpha) and ichnodisparity. An increase in the complexity of morphologic patterns, as illustrated by the undermat mining ichnogenus Oldhamia, is apparent during the Cambrian. The face of the deep sea started to change during the end of the Cambrian and beginning of the Ordovician with the protracted expansion of farming and trapping strategies. The main architectural designs of deep-marine trace fossils (e.g. regular networks, delicate spiral burrows, guided meandering graphoglyptids) were established in the deep sea by the Early Ordovician, recording the first appearance of the Nereites Ichnofacies. Lower to Middle Ordovician deep-marine ichnofaunas are moderately diverse, and fodinichnia commonly dominates rather than graphoglyptids. A significant ichnodiversity and ichnodisparity increase occurred in the Late Ordovician–early Silurian, with ichnofaunas recording higher proportions of graphoglyptids and evidencing the establishment of a deep-marine ecosystem of modern aspect. The distinction between the Nereites and Paleodictyon ichnosubfacies, with the former characterized by the dominance of feeding traces in muddy turbidites and the later by the dominance of graphoglyptids in sandy turbidites, can also be tracked back to the Ordovician radiation. This trend of increased colonization of the deep sea continued through all the Silurian and the Devonian. However, colonization of carbonate turbidites may have lagged behind that of siliciclastic turbidites. The progressive increase in abundance and diversity of graphoglyptids resulted in an increased role of gallery biodiffusers. This faunal turnover in the deep sea was coincident with an increase in oxygenation in slope and base-of-slope settings, which is thought to have been a driver of Ordovician biodiversifications. The formation of permanent open burrows in the deep sea may have increased bioirrigation in the uppermost zone of the deep-sea sediment, therefore increasing ventilation and potentially generating a feedback loop between bioturbation and oxygenation, with the endobenthos engineering its environment. [ABSTRACT FROM AUTHOR]

Burrowing mammals strongly impact plant communities. One of the main effects is accelerating nutrient cycling and thus promoting plant growth. This mechanism is well-studied in grasslands and alpine habitats, but less is known about this phenomenon in arid, cold mountain environments. We studied ecosystem engineering by long-tailed marmots ( Marmota caudata ) by measuring the content of plant nitrogen and phosphorus, as well as nitrogen stable isotopes in plant biomass and marmot feces in a distance gradient up to 20 m from marmot burrows in an extremely arid glacier valley in Eastern Pamir, Tajikistan. We also captured aerial images of the area inhabited by marmots to study the spatial distribution of vegetation. There was a weak relationship between the presence of burrows and vegetation cover on soil not covered by burrow material. Burrow mounds were not colonized by plants, as opposed to other studies, where mounds are often microhabitats that enhance plant diversity. A significant increase in N and P in aboveground green plant biomass in the proximity of burrows was found in one out of six studied plant species. Contrary to our expectations, stable N isotopes did not give further insight into N routing. We assume that plant growth is strongly limited by water availability, which prevents them from utilizing the local increase in nutrients, certainly provided by marmot activity. The results are contrary to numerous studies, which showed that the role of burrowing animals as ecosystem engineers increases with increasing abiotic stress, including aridity. This shows a lack of this type of study at the end of the gradient of abiotic factors., Competing Interests: The authors declare that they have no competing interests., (© 2023 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

Biotic interactions (e.g., predation, competition, commensalism) where organisms directly or indirectly influenced one another are of great interest to those studying the history of life but have been difficult to ascertain from fossils. Considering the usual caveats about the temporal resolution of paleontological data, traces and trace fossils in the sedimentary record can record co-occurrences of organisms or their behaviours with relatively high spatial fidelity in a location. Neoichnological studies and studies on recently buried traces, where direct trophic links or other connections between tracemakers are well-known, may help interpret when and where overlapping traces represented true biotic interactions. Examples from Holocene paleosols and other buried continental sediments in Poland include the tight association between mole and earthworm burrows, forming an ichnofabric representing a predator-prey relationship, and that of intersecting insect and root traces demonstrating the impact of trees as both ecosystem engineers and the basis for food chains. Trampling by ungulates, which leaves hoofprints and other sedimentary disturbances, may result in amensal or commensal effects on some biota in the short term and create heterogeneity that later trace-making organisms, such as invertebrate burrowers, can also respond to in turn, though such modified or composite traces may be challenging to interpret., (© 2023. The Author(s).)

Benthic foraging by fish can modify the nature and rates of fine sediment accrual and the structure and topography of coarse-grained fluvial substrates, with the potential to alter bed material characteristics, particle entrainment thresholds, and bedload transport fluxes. However, knowledge of what controls the nature, extent, and intensity of benthic foraging and the consequent influence of these controls on geomorphic impact remain rudimentary. An ex-situ experiment utilising Barbel Barbus barbus and Chub Leuciscus cephalus extended previous work by considering the role of fish size and species as controls of sediment disturbance by foraging and the implications for bed material characteristics and bedload transport. In a laboratory flume, changes in bed microtopography and structure were measured when a water-worked bed of 5.6–22.6 mm gravels was exposed to four size classes of Barbel (4–5″, 5–6″, 6–8″, 8–10″ in length) and a single size class of Chub (8–10″). In line with other studies that have investigated animal size as a control of zoogeomorphic agency, increasing the size of Barbel had a significant effect on measured disturbance and transport metrics. Specifically, the area of disturbed substrate, foraging depth, and the fish's impact on microtopographic roughness and imbrication all increased as a function of fish size. In a comparison of the foraging effects of like-sized Barbel and Chub, 8–10″ in length, Barbel foraged a larger area of the test bed and had a greater impact on microtopographic roughness and sediment structure. Relative to water-worked beds that were not foraged, bed conditioning by both species was associated with increased bedload transport during the subsequent application of high flows. However, the bedload flux after foraging by Barbel, which is a specialist benthivore, was 150% higher than that following foraging by Chub, which feed opportunistically from the bed, and the total transported mass of sediment was 98% greater. An interesting implication of these results, given the abundance and widespread distribution of foraging fish, is that numerous fish species belonging to a variety of functional groups may be acting as zoogeomorphic agents in rivers, directly affecting bed material conditions and sediment transport fluxes in proportion to their body size and feeding traits. [ABSTRACT FROM AUTHOR]

Ecosystem engineering by insect herbivores occurs as the result of structural modification of plants manipulated by insects. However, only few studies have evaluated the effect of these modifications on the plant responses induced by stem-borers that act as ecosystem engineers. In this study, we evaluated the responses induced by the herbivory of the twig-girdler beetle Oncideres albomarginata chamela (Cerambycidae: Lamiinae) on its host plant Spondias purpurea (Anacardiaceae), and its relationship with the ecosystem engineering process carried out by this stem-borer. Our results demonstrated that O. albomarginata chamela branch removal induced the development of lateral branches increasing the resources needed for the development of future insect generations, of its own offspring and of many other insect species. Detached branches represent habitats with high content of nitrogen and phosphorous, which eventually can be incorporated into the ecosystem, increasing nutrient cycling efficiency. Consequently, branch removal and the subsequent plant tissue regeneration induced by O. albomarginata chamela represent key mechanisms underlying the ecosystem engineering process carried out by this stem-borer, which enhances arthropod diversity in the ecosystem. [ABSTRACT FROM AUTHOR]

Accumulation of Argopecten purpuratus shells often occurs after El Niño events in shallow waters of Independencia Bay (14°17′S–76°10′W; Pisco, Peru). Here we experimentally investigate the effects of their shell accumulation on macrobenthos assemblages in soft bottom, shallow areas of the bay. A field experiment (from May 2006 to May 2007), including four treatments with different coverage levels of empty shells of A. purpuratus , were randomly arranged in: (1) areas devoid of shells (“Empty” treatment: experimental control), (2) 50% of the plot area covered with shells haphazardly distributed over the bottom (“medium” treatment), (3) 100% of the plot area covered with shells, forming a 10 cm valve layer (“full” treatment) and (4) “natural control”. We found a total of 124 taxa throughout the experiment. Polychaetes, crustaceans and mollusks were the most abundant groups in “natural controls”, dominated by the gastropod Nassarius gayi and the polychaetes Prionospio peruana , Platynereis bicanaliculata and Mediomastus branchiferus . The abundance of individuals (N) and the species richness (S) were higher in the “medium” treatment, but only in one month under positive sea bottom thermal anomalies. Similarity analysis (Bray–Curtis) showed that “natural control”, “empty” and “full” treatments were more similar among them than the “medium” treatment. Multidimensional analysis showed no clear species association among treatments and a higher grouping among the samplings of Jun-06, Aug-06 and Nov-06. Our results also showed that the commercial crab Romaleon polyodon and the polyplacophora Tonicia elegans were positively affected by shell accumulations (“medium” treatment), while the limpet Fissurella crassa was negatively affected. Our study shows that directly by changing habitat structure or indirectly by changing sediment characteristics, the addition of scallop shells to the soft bottom can modify the macrobenthic assemblage; however, the seasonal oceanographic variability (e.g. upwelling, El Niño) could have stronger effects controlling this system than the presence of the shells itself. [ABSTRACT FROM AUTHOR]

Background and aims: Intense rains are becoming more frequent. By causing waterlogging, they may increase soil erosion and soil surface compaction, hamper seedling establishment, and reduce plant growth. Since anecic earthworms make vertical burrows that improve water infiltration, we hypothesised that they can counteract such disturbance. Methods: In a field experiment, intact soil mesocosms with ryegrass ( Lolium multiflorum), with or without introduced adult Lumbricus terrestris, underwent either a precipitation regime with two intense rain events (36 mm, at beginning and end of spring), or a control regime with the same cumulative rainfall but no intense events. Short-term response of soil moisture and lagged response of plant growth were measured, and soil macroporosity was quantified. Results: Intense rains reduced ryegrass shoot biomass (by 16-21 % on average) only in the absence of earthworms. Waterlogging duration aboveground was not affected, whereas soil moisture contents after intense rainfall tended to drop faster with earthworms present. Continuous vertical macropores were found only in the mesocosms to which earthworms had been added. The number of such macropores was 2.4 times higher under the intense precipitation regime, despite similar earthworm survival. Conclusions: We found that anecic earthworms can offset negative effects of intense rainfall on plant growth aboveground. Underlying mechanisms, such as macropore formation and enhanced nutrient cycling, are discussed. We also observed that altered precipitation patterns can modify earthworm burrowing behaviour, as earthworms had produced more burrows under the intense regime. [ABSTRACT FROM AUTHOR]

Epifaunal polychaetes inhabit a range of habitat structures built by other organisms, such as ascidians. Here, we examine: i) the polychaete fauna inhabiting aggregations of the ascidian Pyura chilensis in central Chile; ii) the relationship between sample volume (aggregation size) and polychaete assemblage variables; and iii) the effect of a tube-building chaetopterid on the polychaete assemblage structure. The chaetopterid tube load on aggregations determines two ascidian morphotypes, those with a high load of chaetopterid tubes (HT morphotype) and those with a low load of chaetopterid tubes (LT morphotype). From a total of 38 aggregations studied, we found 5,524 specimens belonging to 35 species of polychaetes. Three species were the most abundant in the aggregations ( Phyllochaetopterus socialis, Nicolea lobulata, and Typosyllis magdalena), reaching 22% of total abundance. The number of species and individuals increased with sample volume, but only the number of species number varied between morphotypes. Sample volume and the chaetopterid tubes influenced the polychaete assemblage structure, evidencing differences between morphotypes. We suggest that both sample volume and the habitat structuring capacity of the chaetopterid tubes change the habitat complexity of the ascidian aggregations and, hence, produce differences between morphotypes related to the polychaete assemblage structure. [ABSTRACT FROM AUTHOR]

Creating ditches to drain forests to improve timber production is often overlooked as an ecosystem modifier; the practice is commonplace and not easy to see, and it changes the ecosystem slowly. However, a closer look reveals a complex of feedback-regulated, largely indirect, and wideranging impacts of the changed hydrology on biodiversity. Our synthesis of those fragmentarily studied impacts highlights a frequent formation of unprecedented biotic assemblages with unclear long-term prospects and consequences for the ecosystem functioning. We present a contextdependent framework to support harmonizing the ditching practices with sustainable forest management--a challenging but scientifically exciting task that requires novel approaches to landscape planning, silviculture, and wetland restoration. [ABSTRACT FROM AUTHOR]

New approaches to human-environment interactions are beginning to move beyond a narrow focus on individuals and simple (patch-level) predatory or competitive interactions. These approaches link nonequilibrium theory from community and landscape ecology with theories of individual decision making from behavioral ecology to explore new ways of approaching complex issues of diachronic change in behavior, subsistence, and social institutions. I provide an overview of two such approaches, one to understand long-term hunting sustainability among mixed forager-horticulturalists in the wet tropics and the other to understand how foragers act as ecosystem engineers in a dry perennial grassland in Australia. I conclude by describing the implications of new approaches that incorporate anthropogenic 'intermediate' disturbance (an emergent property of human-environment interaction) as a force shaping environments through time and space, and in so doing patterning the sustainability of subsistence, ways of sharing, ownership norms, and even structures of gendered production. [ABSTRACT FROM AUTHOR]

An important and highly active research agenda has developed at the interface of fluvial geomorphology and ecology that addresses the capacity for vegetation and animals to act as ecosystem engineers within fluvial systems. This paper briefly introduces this research domain and describes the 15 papers that contribute to the special issue on 'Dynamic riverine landscapes: the role of ecosystem engineers'. The papers illustrate the breadth of research activity at this interface, investigating the influence of a range of ecosystem engineering organisms through a combination of field study, laboratory experiments, numerical simulation and analysis of remotely sensed data. Together, the papers address a series of key themes: conceptual frameworks for feedbacks between aquatic biota, hydraulics, sediment dynamics and nutrient dynamics and their quantification through experimental and field research; the potential contribution of ecosystem engineering species to assist river recovery and restoration; and the contribution of riparian vegetation to bank stability and morphodynamics across a range of spatio-temporal scales. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Many species of millimetric fungus-harvesting termites collectively build uninhabited, massive mound structures enclosing a network of broad tunnels that protrude from the ground meters above their subterranean nests. It is widely accepted that the purpose of these mounds is to give the colony a controlled microclimate in which to raise fungus and brood by managing heat, humidity, and respiratory gas exchange. Although different hypotheses such as steady and fluctuating external wind and internal metabolic heating have been proposed for ventilating the mound, the absence of direct in situ measurement of internal air flows has precluded a definitive mechanism for this critical physiological function. By measuring diurnal variations in flow through the surface conduits of the mounds of the species Odontotermes obesus, we show that a simple combination of geometry, heterogeneous thermal mass, and porosity allows the mounds to use diurnal ambient temperature oscillations for ventilation. In particular, the thin outer flutelike conduits heat up rapidly during the day relative to the deeper chimneys, pushing air up the flutes and down the chimney in a closed convection cell, with the converse situation at night. These cyclic flows in the mound flush out CO2 from the nest and ventilate the colony, in an unusual example of deriving useful work from thermal oscillations. [ABSTRACT FROM AUTHOR]

Traditionally, studies on vegetation succession have focused either on plant-plant interactions or on interactions between plants and their physical environment, for example through organic matter build-up and increased nutrient cycling. These interactions can change conditions for macrodetritivores that feed on plant litter, but their role in vegetation succession is rarely studied. In this paper, we explore whether the bioturbating crustacean macrodetritivore Orchestia gammarellus alters soil conditions in a saltmarsh ecosystem in such a way that it promotes late-successional, less stress-tolerant plant species at the expense of early successional species., To answer this, we performed a field and a laboratory experiment in which we manipulated abundances of O. gammarellus, and studied the consequences for soil physical and chemical parameters and for vegetation community composition., Our field experiment showed that O. gammarellus stimulated nitrogen mineralization, likely resulting from the positive effect of this macrodetritivore on soil aeration and litter decomposition. Moreover, results from the laboratory experiment showed that O. gammarellus negatively affected dicot seedling survival of mainly early successional plant species, likely through grazing, thus affecting plant community composition., The experiments together provided evidence that O. gammarellus promotes late-successional plant species in multiple ways: by alleviation of anoxic conditions, by promoting nutrient cycling and by selective herbivory on early successional species., Synthesis. By demonstrating that a species traditionally considered as part of the detrital ('brown') food web is thus an important accelerator of vegetation succession, this study documents an important but often overlooked link in food web and ecosystem ecology. [ABSTRACT FROM AUTHOR]

By creating novel habitats, habitat-modifying species can alter patterns of diversity and abundance in marine communities. Many sea urchins are important habitat modifiers in tropical and temperate systems. By eroding rocky substrata, urchins can create a mosaic of urchin-sized cavities or pits separated by exposed, often flat surfaces. These microhabitats appear to harbor distinct assemblages of species. We investigated how a temperate rocky intertidal community uses three small-scale (<100 cm2) microhabitats created by or adjacent to populations of the purple sea urchin ( Strongylocentrotus purpuratus): pits occupied by urchins, unoccupied pits, and adjacent flat spaces. In tidepools, flat spaces harbored the highest percent cover of algae and sessile fauna, followed by empty pits and then occupied pits. The Shannon diversity and richness of these sessile taxa were significantly higher in flat spaces and empty pits than in occupied pits. The composition of these primary space holders in the microhabitats also varied. Unlike primary space holders, mobile fauna exhibited higher diversity and richness in empty pits than in flat spaces and occupied pits, although results were not significant. The protective empty pit microhabitat harbored the highest densities of most trophic functional groups. Herbivores, however, were densest in flat spaces, concordant with high algal coverage. These results suggest the habitats created by S. purpuratus in addition to its biological activities alter community structure at spatial scales finer than those typically considered for sea urchins. [ABSTRACT FROM AUTHOR]

Although much research has examined the characteristics of Olympic marmot behavior and habitat, most studies mention the direct bioturbation effects of these marmots incidentally in an effort to examine other phenomena. A better understanding of marmot impacts on soil properties can provide a baseline for examining additional phenomena that are influenced by marmot activity. Soil surface and subsurface temperature, compaction, and moisture were measured in situ on abandoned marmot burrows in northeastern Olympic National Park, Washington. Soil samples were collected to analyze texture, pH, salinity, P, K, and organic matter content. Results indicated that soil compaction and organic matter were significantly reduced on abandoned marmot burrows when compared to undisturbed sites. Surface temperatures were typically warmer on marmot-disturbed soils, and subsurface temperatures were cooler. Soil moisture, texture, pH, salinity, and macronutrients were surprisingly similar on both disturbed and undisturbed soils. Findings suggest that Olympic marmots affect both physical and chemical soil characteristics, but additional research will be needed to evaluate the duration and extent of their impacts. [ABSTRACT FROM AUTHOR]

Worldwide, marine rocky shores are being modified by alien species, but their successive impacts are rarely recorded. We documented sequential invasions of Marcus Island on the west coast of South Africa by comparing communities from 1980 (pre-invasion), 2001 (after invasion by the mussel Mytilus galloprovincialis) and 2012 (following invasions by another mussel, Semimytilus algosus, and the barnacle Balanus glandula). Their influence on habitat complexity was measured with a novel technique enabling retrospective calculation of historical complexity. In 1980, habitat complexity, invertebrate abundance and species richness decreased from the low-shore to the high-shore, but homogenised in 2001 after M. galloprovincialis elevated habitat complexity across most of the shore. In 2012, these variables returned to pre-invasion patterns, after M. galloprovincialis declined in the high-shore and was replaced there by B. glandula. With the first mussel invasion, several indigenous species extended up the intertidal, but retreated once M. galloprovincialis receded. Community composition differed significantly among nearly all years and zones, irrespective of whether the alien species were included in the analyses or not. Some once-dominant native species were negatively affected by the invasions: one indigenous mussel, Choromytilus meridionalis, disappeared by 2012, and another, Aulacomya atra, declined. The abundance of recruits of the limpet Scutellastra granularis rose and fell with the arrival and recession of M. galloprovincialis, but adults were adversely affected. Changes to habitat complexity induced by sequential invasions supported hypothesised changes in invertebrate abundance and species richness, but could not alone predict changes in community composition, which were also influenced by zonation. [ABSTRACT FROM AUTHOR]

Background:Studies on plant–plant interactions in alpine ecosystems show a strong bias for temperate vs. tropical latitudes and pay limited attention to the implications of biophysical heterogeneity beyond the local plant scale. Aims:To evaluate the effects of a dominant shrub (Hypericum laricifolium) on community organisation, integrating multiple scales of analysis, in a high Andean páramo in Venezuela. Methods:We compared plant cover, species richness and Shannon diversity between plots placed under the shrub and outside (plant scale); quantified the spatial relations ofHypericumwith its conspecifics, heterospecifics and rocks at different radial distances, using covariance functions (patch scale); analysed the effects ofHypericumshrubs on total species richness in the community (site scale); and evaluated the consistency of our results among four sites within the same region (between-site scale). Results:Average species richness, Shannon diversity, and the abundance of common forbs and conspecific shrubs were consistently higher inside theHypericumshrub, while the exoticRumex acetosellawas more abundant in open areas. However, the aggregated spatial distribution of conspecifics and other species extended beyond the local plant scale and there were no clear effects ofHypericumshrubs on community-level species richness. Conclusions:Shrubs can function as foundation species in tropical alpine environments, modifying local community structure and alpha diversity, but not necessarily the species richness of the overall community. Our results stress the need of analysing multiple spatial scales to interpret the role of plant–plant interactions (facilitation/competition) in heterogeneous alpine ecosystems. [ABSTRACT FROM AUTHOR]

"Ecosystem engineering" describes habitat alteration by an organism that affects another organism; such nontrophic interactions between organisms are a current focus in ecological research. Our study quantifies the actual impact an ecosystem engineer can have on another species by using a previously identified model system--peccaries and rainforest frogs. In a 4-year experiment, we simulated the impact of peccaries on a population of Allobates femoralis (Dendrobatidae) by installing an array of artificial pools to mimic a forest patch modified by peccaries. The data were analyzed using a gradual before-after control-impact (gBACI) model. Following the supplementation, population size almost doubled as a result of increased autochthonous recruitment driven by a higher per-capita reproduction of males and a higher proportion of reproducing females. The effect was evenly distributed across the population. The differential response of males and females reflects the reproductive behavior of A. femoralis, as only the males use the aquatic sites for tadpole deposition. Our study shows that management and conservation must consider nontrophic relationships and that human "ecosystem engineering" can play a vital role in efforts against the "global amphibian decline." [ABSTRACT FROM AUTHOR]

Aquatic organisms that produce epibenthic structures such as saltmarsh plants play key roles in habitat functioning through their ecosystem engineering effects. Intertidal Spartina species are well known for modifying tidal hydrodynamic and sediment processes, affecting cohabiting infaunal organisms. The stout razor clam Tagelus plebeius is an infaunal filter-feeding species that inhabits a broad range of mudflats (MF) and Spartina saltmarshes (SM) along the American Atlantic coast. Through descriptive and experimental approaches conducted at the Bahía Blanca estuary (Argentina, 38°47′S, 62° 20′W), we evaluated ecosystem engineer effects of Spartina alterniflora (due to changes in sediment and water characteristics) on somatic and shell growth of T. plebeius . Comparison of bulk sediment parameters indicated that the sediment is more easily eroded in the SM than in the MF, but softer in the latest. In addition, food supply for clams (i.e., total particulate organic matter) was higher in the MF although food quality (i.e., percentage of organic matter in the water column) was in general higher in SM. Shell growth was higher but clam condition index (CI) was lower in the MF, and the opposite pattern was found in the SM. These results represent an uncoupling between shell and somatic growth with a positive effect of S. alterniflora on the CI of clams. Nevertheless, results of field experiments manipulating stems and roots of plants separately suggested that the effect of Spartina on clam's CI was not due to the structural changes generated by plant presence itself, although a better food quality in the SM may be related to the larger clams CI. [ABSTRACT FROM AUTHOR]

Despite years of research on small mammal disturbance effects on plant diversity, predicting the direction and magnitude of these effects remains elusive. Models such as the intermediate disturbance hypothesis, the perturbation hypothesis, or the ecosystem engineering hypothesis of small mammal disturbance, show considerable overlap but fail to account for key variable interactions and thus provide mainly post hoc explanations. Recent reviews have emphasized the importance of small mammals to basic and applied ecology. Re‐examining the mechanisms underlying their disturbance effects is thus timely. Here I present the Slope‐Hump Model, which integrates previous models and insights from the literature, and which is capable of predicting the direction and relative magnitude of disturbance effects on plant diversity. These predictions qualitatively match the results of recent meta‐analyses. The model also suggests new patterns and predictions that can stimulate both pure and applied ecology research.

There has been debate about animals’ contribution to ocean circulation, called biomixing, or biogenic mixing. The energy input of schooling fish is significant but the eddies may be too small; so energy is dissipated as heat before impacting oceanic structure. I suggest that high turbulence caused by some very large aggregations of small animals has an important impact via a more direct ecosystem feedback process than overall ocean circulation. In the model presented here, large schools exhibit cooperative behavior and act like giant sieves grading zooplankton through individual swimmer’s wakes, which focus the best prey in predictable positions. Following schoolers exploit these patterns. Then schools leave, in their wakes, chaotic turbulence enhancing growth of the smaller zooplankton and phytoplankton which has been graded out by the school. The result is a different community structure of plankton than would exist without such biomixing. Changes to plankton abundance and community structure on oceanic scales over the past century are correlated to overfishing and are consistent with this concept.

The rapid origination and diversification of major animal body plans during the early Cambrian coincide with the rise of Earth's first animal-built framework reefs. Given the importance of scleractinian coral reefs as ecological facilitators in modern oceans, we investigate the impact of archaeocyathan (Class Archaeocyatha) reefs as engineered ecosystems during the Cambrian radiation. In this study, we present the first high-resolution, three-dimensional (3D) reconstructions of branching archaeocyathide (Order Archaeocyathida) individuals from three localities on the Laurentian paleocontinent. Because branched forms in sponges and corals display phenotypic plasticity that preserve the characteristics of the surrounding growth environment, we compare morphological measurements from our fossil specimens to those of modern corals to infer the surface conditions of Earth's first reefs. These data demonstrate that archaeocyaths could withstand and influence the flow of water, accommodate photosymbionts, and build topographically complex and stable structures much like corals today. We also recognize a stepwise increase in the roughness of reef environments in the lower Cambrian, which would have laid a foundation for more abundant and diverse coevolving fauna., (© 2022 John Wiley & Sons Ltd.)

Large mammalian grazers can alter the biotic and abiotic features of their environment through their impacts on vegetation. Grazing at moderate intensity has been recommended for biodiversity conservation. Few studies, however, have empirically tested the benefits of moderate grazing intensity in systems dominated by native grazers. Here we investigated the relationship between (1) density of native eastern grey kangaroos, Macropus giganteus, and grass structure, and (2) grass structure and reptiles (i.e. abundance, richness, diversity and occurrence) across 18 grassland and grassy Eucalyptus woodland properties in south-eastern Australia. There was a strong negative relationship between kangaroo density and grass structure after controlling for tree canopy cover. We therefore used grass structure as a surrogate for grazing intensity. Changes in grazing intensity (i.e. grass structure) significantly affected reptile abundance, reptile species richness, reptile species diversity, and the occurrence of several ground-dwelling reptiles. Reptile abundance, species richness and diversity were highest where grazing intensity was low. Importantly, no species of reptile was more likely to occur at high grazing intensities. Legless lizards (Delma impar, D. inornata) were more likely to be detected in areas subject to moderate grazing intensity, whereas one species (Hemiergis talbingoensis) was less likely to be detected in areas subject to intense grazing and three species (Menetia greyii, Morethia boulengeri, and Lampropholis delicata) did not appear to be affected by grazing intensity. Our data indicate that to maximize reptile abundance, species richness, species diversity, and occurrence of several individual species of reptile, managers will need to subject different areas of the landscape to moderate and low grazing intensities and limit the occurrence and extent of high grazing. [ABSTRACT FROM AUTHOR]