David C Aldridge

University of Cambridge | Cam · Department of Zoology

Many taxa around the globe are threatened by often unexplained mass mortality events (MMEs), which can decimate populations and compromise key ecosystem functions. One example of a highly threatened taxon facing frequent MMEs is freshwater mussels (Unionida). There has been a recent increase in interest in understanding the causes of freshwater mus...

Environmental hazards associated with the global food system threaten societal integrity. Yet, there is a major data gap in the global understanding of how the prevalence of hazards is changing over time, how different classes of hazard are distributed, and whether the combined literature represents hazard prevalence equitably across research, poli...

Freshwater mussels are a globally threatened taxon, but little is known about population trajectories for species outside Europe and North America. To contribute to understanding of mussel conservation status outside these regions, we surveyed mussel and other invertebrate populations in waterbodies across Dhaka, Bangladesh, to assess population tr...

Preserved biological communities can provide baseline data about the historical ecosystems and environmental conditions that preceded recent anthropogenic alteration. Freshwater mussel shells show particularly good preservation, and the shell assemblages commonly found during archaeological excavations can offer insights into past ecosystems. We st...

This study highlights the conservation problems faced by the tiny freshwater bivalves of the family Sphaeriidae, also known as pea, pill, or fingernail clams (or mussels) in Europe. Despite their global distribution, assumed ecological importance, and potential uses, basic knowledge about their taxonomy, biology, and ecology is very limited and muc...

Logged and disturbed forests are often viewed as degraded and depauperate environments compared with primary forest. However, they are dynamic ecosystems¹ that provide refugia for large amounts of biodiversity2,3, so we cannot afford to underestimate their conservation value⁴. Here we present empirically defined thresholds for categorizing the cons...

Here, we present a synthesis of the available knowledge on the Giant Freshwater Pearl Mussel Pseudunio auricularius (= Margaritifera auricularia) (Spengler, 1793). We also identify critical knowledge gaps that require attention for effective conservation guidance and species recovery. Pseudunio auricularius is one of Europe’s most endangered invert...

The "Great Acceleration" beginning in the mid-20th century provides the causal mechanism of the Anthro-pocene, which has been proposed as a new epoch of geological time beginning in 1952 CE. Here we identify key parameters and their diagnostic palaeontological signals of the Anthropocene, including the rapid breakdown of discrete biogeographical ra...

Abstract: The “Great Acceleration” of the mid-20th century provides the causal mechanism of the Anthropocene, which has been proposed as a new epoch of geological time beginning in 1952 CE. Here we identify key parameters and their diagnostic palaeontological signals of the Anthropocene, including the rapid breakdown of discrete biogeographical ran...

Future dynamics of biological invasions are highly uncertain because they depend on multiple social–ecological drivers. We used a scenario‐based approach to explore potential management options for invasive species in Europe. During two workshops involving a multidisciplinary team of experts, we developed a management strategy arranged into 19 goal...

1. Land-use change and agricultural expansion have caused marked biodiversity loss in Southeast Asia, but impacts on freshwater communities have been very little studied. Semi-aquatic bugs are abundant in streams, provide prey for many other animals, and are sensitive to environmental change, making them a relevant group for studying land-use chang...

The functional stability of ecosystems depends greatly on interspecific differences in responses to environmental perturbation. However, responses to perturbation are not necessarily invariant among populations of the same species, so intraspecific variation in responses might also contribute. Such inter-population response diversity has recently b...

Understanding the ecological assembly of parasite communities is critical to characterise how changing host and environmental landscapes will alter infection dynamics and outcomes. However, studies frequently assume that (a) closely related parasite species or those with identical life-history strategies are functionally equivalent, and (b) the sam...

Despite the diverse ecosystem services that forested stream margins (“riparian buffer strips”) can provide in agricultural landscapes, understanding of their biodiversity impacts in the tropics is lacking. Stream invertebrates support many ecosystem functions and several groups are valuable bioindicators of environmental conditions. Semi-aquatic bu...

Invasive alien species are one of the major threats to global biodiversity, ecosystem integrity, nature's contributions to people and human health. While scenarios about potential future developments have been available for other global change drivers for quite some time, we largely lack an understanding of how biological invasions might unfold in...

The global population urgently requires alternative food sources that provide the micronutrient-rich profile of meat and fish but with lower environmental cost. We present a solution in the form of ‘Naked Clams’ (teredinids/shipworms) - a seldom researched group of bivalves, that feature tiny shells and live in and feed on wood, turning it into pro...

Non-technical summary Global conflicts and the pandemic reveal the risks of food import reliance. In the UK, pandemic, Brexit, and Ukraine war caused food price spikes. To bolster food security, the UK needs to produce and consume more domestically, including nutrient-rich bivalve mollusks. Current mollusk exports hinder domestic food sources. Prom...

Freshwater mussels (Bivalvia: Unionidae) are often described as ecosystem engineers, with the capacity to alter abiotic habitats; this can facilitate certain macroinvertebrate taxa, increasing biodiversity and potentially altering community composition. Mussel species are often implicitly considered to be broad ecological equivalents, with similar...

The biodiversity‐disease relationship states that increased species richness leads to lower pathogen pressure (i.e. the dilution effect), an effect that erodes with biodiversity loss. However, whether losses of the dilution effect can trigger extinction cascades remains largely unexplored. To explore this idea, we consider declines in freshwater mu...

The expansion of mussel aquaculture is limited by the availability of spat and production on land is dependent on costly cultures of microalgae as feed. Substitution of algae with microencapsulated feeds can reduce feed contaminations, ease the storage and extend the shelf life, ensuring stable production of consistent quality at sustainable costs....

Bivalve mollusc meat—that from mussels, clams, and oysters—offers a highly sustainable and nutritious alternative to meat from other shellfish, fish, or livestock. However, bivalves are an unpopular mass market food relative to these other meat items, limiting our ability to reap potential environmental and health benefits. Hence, this study aimed...

Since their introduction to North America in the 1980s, research to develop effective control tools for invasive mussels (Dreissena polymorpha and D. rostriformis bugensis) has been ongoing across various research institutions using a range of testing methods. Inconsistencies in experimental methods and reporting present challenges for comparing da...

Small-scale octopus fisheries represent an underexplored source of nutrients and socioeconomic benefits for populations in the tropics. Here we analyse data from global seafood databases and published literature, finding that tropical small-scale octopus fisheries produced 88,000 t of catch and processed octopus in 2017, with a landed value of US$...

Understanding how ecological communities are assembled remains a key goal of ecosystem ecology. Because communities are hierarchical, factors acting at multiple scales can contribute to patterns of community structure. Parasites provide a natural system to explore this idea, as they exist as discrete communities within host individuals, which are t...

We identified 14 emerging and poorly understood threats and opportunities for addressing the global conservation of freshwater mussels over the next decade. A panel of 17 researchers and stakeholders from six continents submitted a total of 56 topics that were ranked and prioritized using a consensus-building Delphi technique. Our 14 priority topic...

A pioneering, quantitative study published in Journal of Animal Ecology in 1966 on freshwater mussel populations in the River Thames, UK, continues to be cited extensively as evidence of the major contribution that mussels make to benthic biomass and ecosystem functioning in global river ecosystems. Ecological alteration, as well as declines in fre...

Biological early warning systems (BEWSs) monitor the behaviour or physiology of living organisms as an indirect mechanism to sense local environmental changes, and have become a widely established tool for monitoring water pollution. Complementary to conventional chemical and physical techniques, their strength lies in the ability to continuously m...

Europe has a long history of human pressure on freshwater ecosystems. As pressure continues to grow and new threats emerge, there is an urgent need for conservation of freshwater biodiversity and its ecosystem services. However, whilst some taxonomic groups, mainly vertebrates, have received a disproportionate amount of attention and funds, other g...

Length–biomass equations are relatively easy and cost‐effective for deriving insect biomass. However, the exact relationship can vary between taxa and geographical regions. Semi‐aquatic bugs are abundant and are indicators of freshwater quality, but there are no studies investigating the effect of habitat disturbance on their biomass, although it i...

Parasite conservation is important for the maintenance of ecosystem diversity and function. Conserving parasites relies first on understanding parasite biodiversity and second on estimating the extinction risk to that biodiversity. Although steps have been taken independently in both these areas, previous studies have overwhelmingly focused on helm...

1. Invasive alien species are one of the major threats to global biodiversity, ecosystem integrity, natures contribution to people and human health. While scenarios about potential future developments have been available for other global change drivers for quite some time, we largely lack an understanding of how biological invasions might unfold in...

The use of systematic reviews to collate and summarise evidence is considered one of the great intellectual achievements of recent times. Evidence synthesis has had far-reaching impacts and has helped to inform decision-making in multiple fields. However, it also faces three problems: (i) reviews cannot be relevant to everyone, hampering decision-m...

Future dynamics of biological invasions are highly uncertain because they depend on multiple environmental, societal and socio-economic drivers. We adopted a qualitative scenario approach to explore the future of invasive alien species (IAS) in Europe and created an overall strategy for their management that considers different plausible future dev...

The management of invasive species requires analytical tools that can synthesise the increasing and complex information generated through risk assessment protocols. To that end, fault tree analysis (FTA) provides a means to conceptually map all of the events leading to a particular undesired scenario with associated probabilities and uncertainty. W...

Plastic debris widely pollutes freshwaters. Abiotic and biotic degradation of plastics releases carbon-based substrates that are available for heterotrophic growth, but little is known about how these novel organic compounds influence microbial metabolism. Here we found leachate from plastic shopping bags was chemically distinct and more bioavailab...

Global expansion of bivalve aquaculture can drive sustainable protein production. Inland culture of mussel spat can play an important role in supporting extensive mussel farming. Nursery culture of bivalves is, however, dependent on nutritious, cost‐efficient, and more reliable diets for spat. The aim of this study was to assess the impact of dieta...

Identification of ecosystem services, i.e. the contributions that ecosystems make to human well-being, has proven instrumental in galvanising public and political support for safeguarding biodiversity and its benefits to people. Here we synthe-sise the global evidence on ecosystem services provided and disrupted by freshwater bivalves, a heterogeno...

Parasites can indirectly affect ecosystem function by altering host phenotype, but the trait‐mediated impacts of parasitism at an ecosystem level remain poorly characterised. However, understanding the influence of parasites is central to understanding the ecosystem services provided by host species, especially in an era of global environmental cha...

In the present study, we evaluated the effects of different environments on the filtering rate (FR), mortality, and biodeposition (BD) of the freshwater mussel Unio douglasiae in bloom waters containing the toxic cyanobacterium Microcystis aeruginosa. The mean FR of 19 selected individuals (shell length, 5.0-9.8 cm) was 0:30 ± 0:03 L g −1 h −1 (ran...

Early detection and rapid response are cornerstones of effective invasive species management. However, these strategies can be challenging to implement when the arrival of a non-native species has not been predicted, as may be the case when a species is discovered large distances from known populations. Brown marmorated stink bugs Halyomorpha halys...

Significance Ship movements related to fishing, tourism, research, and supply expose the Antarctic continent to human impacts. Until now, only rough estimates or industry-specific information have been available to inform evidence-based policy to mitigate the introduction of nonnative marine species. Antarctica’s Southern Ocean supports a unique bi...

It is now clear that the routine embedding of experiments into conservation practice is essential for creating reasonably comprehensive evidence of the effectiveness of actions. However, an important barrier is the stage of identifying testable questions that are both useful but also realistic to carry out without a major research project. We ident...

Slow growth in the bivalve mariculture sector results from production inefficiencies, food safety concerns, limited availability of convenience products and low consumer demand. Here we assess whether bivalves could meet mass-market seafood demand across the bivalve value chain. We explore how bivalve production could become more efficient, strateg...

Data on biomass is an important component of studying ecosystems, but measuring the weight of individual samples requires a lot of investment in time and equipment. Length-biomass equations provide an easy and cost-effective way of deriving biomass data for whole communities, but relationships vary between taxa and habitats. Semi-aquatic bugs are i...

The naiads, large freshwater mussels (Unionida), have very long life spans, are large-bodied, and produce thousands to millions of larvae (glochidia) which typically must attach to host fish tissues to metamorphose into a juvenile mussel. Glochidia develop within a female's marsupial gill demibranch, thus their number is restricted by female size....

The crisis generated by the emergence and pandemic spread of COVID-19 has thrown into the global spotlight the dangers associated with novel diseases, as well as the key role of animals, especially wild animals, as potential sources of pathogens to humans. There is a widespread demand for a new relationship with wild and domestic animals, including...

Isotopic analyses of the incrementally growing baleen in Mysticeti have been used to learn about their feeding and movement patterns. Using methods previously applied to Pacific minke whales, stable δ15N and δ13C isotope values were measured along the baleen plates of male and female minke whales from two locations in the Northeast Atlantic. The sa...

There is growing acknowledgement that human-induced change can push ecosystems beyond tipping points, resulting in the dramatic and sudden loss of vital ecosystem services. Invasive non-native species (INNS) are spreading rapidly due to anthropogenic activities and climate change and can drive changes to ecosystem functioning by altering abiotic co...

Mytilus galloprovincialis spats and adults were cultured at hatchery semi-industrial scale for 8 weeks with different feeding conditions: 1) NC (Negative Control: no food supplied); 2) A (commercial microalgae: 100% ShellfishReed); 3) B (BioBullets as alternative singular diet: 100% Schyzochytrium); 4) ABL (Alternative mixed diet: 40% A + 60% B; 5)...

• Parasites can negatively affect hosts at individual, population, and species-level scales. However, the link between individual- and population-level impacts is often poorly understood. In particular, the population-level response to parasitism may alter wider ecosystem dynamics if animals with ecosystem engineering capabilities are infected. • H...

Presence–absence data holds less information about communities than abundance data (Blanchet et al. 2020). However, presence–absence data is often all community ecologists have to work with. The relationship between presence–absence and abundance data is especially relevant in parasitological studies, as it is often difcult to count parasites. Rece...

Societal biosecurity, measures built into everyday society to minimize risks from pests and diseases, is an important aspect of managing epidemics and pandemics. We aimed to identify societal options for reducing the transmission and spread of respiratory viruses. We used SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) as a case study...

With the biodiversity crisis continuing unchecked, we need to establish levels and drivers of extinction risk, and reassessments over time, to effectively allocate conservation resources and track progress towards global conservation targets. Given that threat appears particularly high in freshwaters, we assessed the extinction risk of 1428 randoml...

Freshwater mussels are one of the most endangered animal groups globally, making them a high conservation priority. Conservationists increasingly employ translocation or captive breeding procedures to support ailing populations, and the ecosystem engineering capabilities of mussels are being increasingly harnessed in bioremediation projects. Howeve...

Invasive quagga mussels (Dreissena rostriformis bugensis) are an emerging threat to the functioning and management of freshwater ecosystems. Quagga mussels were first recorded in the UK in 2014 and have subsequently established at high densities in a number of major reservoirs. Through implementing a Progressive-Change BACIPS (Before-After-Control-...

Aquaculture has grown rapidly to play a crucial economic and social role and meet the increasing global demand for seafood. As aquaculture intensifies, there is increasing pressure to find more sustainable practices that save resources and reduce waste. Major wastes and by-products from aquaculture were quantified across a full range of farming typ...

Understanding how environmental drivers influence the assembly of parasite communities, in addition to how parasites may interact at an infracommunity level, are fundamental requirements for the study of parasite ecology. Knowledge of how parasite communities are assembled will help to predict the risk of parasitism for hosts, and model how parasit...

Freshwater ecosystems provide essential resources and vital ecosystem services. These ecosystems exist in a delicate state of balance and are under increasing anthropogenic and climatic pressures. One of the major anthropogenic threats to freshwater ecosystems is eutrophication that often leads to algal blooms, some of which may be extremely harmfu...

Bitterlings, a group of freshwater teleosts, provide a fascinating example among vertebrates of the evolution of brood parasitism. Their eggs are laid inside the gill chamber of their freshwater mussel hosts where they develop as brood parasites. Studies of the embryonic development of bitterlings are crucial in deciphering the evolution of their d...

Multiple national and international trends and drivers are radically changing what biological security means for the United Kingdom (UK). New technologies present novel opportunities and challenges, and globalisation has created new pathways and increased the speed, volume and routes by which organisms can spread. The UK Biological Security Strateg...

The Unionidae represent an excellent model taxon for unravelling the drivers of freshwater diversity, but, phylogeographic studies on Southeast Asian taxa are hampered by lack of a comprehensive phylogeny and mutation rates for this fauna. We present complete female- (F) and male-type (M) mitogenomes of four genera of the Southeast Asian clade Cont...