Martin Wilkes

University of Essex · School of Biological Sciences

Global change threatens invertebrate biodiversity and its central role in numerous ecosystem functions and services. Functional trait analyses have been advocated to uncover global mechanisms behind biodiversity responses to environmental change, but the application of this approach for invertebrates is underdeveloped relative to other organism gro...

Excess fine sediment, comprising particles <2 mm in diameter, is a major cause of ecological degradation in rivers. The erosion of fine sediment from terrestrial or aquatic sources, its delivery to the river, and its storage and transport in the fluvial environment are controlled by a complex interplay of physical, biological, and anthropogenic fac...

The growing use of functional traits in ecological research has brought new insights into biodiversity responses to global environmental change. However, further progress depends on overcoming three major challenges involving (1) statistical correlations between traits, (2) phylogenetic constraints on the combination of traits possessed by any sing...

Alpine river biodiversity around the world is under threat from glacier retreat driven by rapid warming, yet our ability to predict the future distributions of specialist cold-water species is currently limited. Here we link future glacier projections, hydrological routing methods and species distribution models to quantify the changing influence o...

BACKGRUND: Goldfish Carassius auratus is a popular ornamental fish extensively cultured worldwide. Sperm cryopreservation is a common fish breeding method that ensures sperm availability around the year. Studies on cryopreservation of goldfish sperm, especially on the suitability of cryoprotectant types and pre-freezing time, are scarcely available...

Most empirical metacommunity studies rely solely on morphological identification of taxa, precluding the species-level identification of several biotic groups, which can influence the characterization of metacommunities. DNA metabarcoding enables inference of species and even intraspecific diversity from community samples but has rarely been used t...

The climbing perch, Anabas testudineus is a freshwater fish that has economic value in Indonesia. It is cultured in the country, but the breeding technology, specifically sperm storage, is not well developed. Sperm cryopreservation is one of the preservation methods that need to be developed to support fish breeding technology. The type of cryoprot...

Barramundi, Lates calcarifer is one of the commercial fish in Indonesia and other Southeast Asian countries. The species inhabits the coastal waters and is vulnerable to changes in the terrestrial environment due to coastal degradation, pollution, and global warming. The increase in temperature as a consequence of global warming affects the distrib...

Betta rubra is an ornamental freshwater fish endemic to northern Sumatra, Indonesia. The B. rubra population has decreased in recent decades, and is classified as an endangered species in the IUCN Red List. This study aims to report for the first time infection by L. cyprinacea in B. rubra harvested from the Aceh Besar region of Indonesia. The fish...

Fine sediment is a leading cause for the decline of aquatic biodiversity globally. There is an urgent need for targeted monitoring to identify where management methods are required in order to reduce the delivery of fine sediment to aquatic environments. Existing sediment-specific biomonitoring indices and indices for general ecological health (tax...

Nature-based solutions are widely advocated for freshwater ecosystem conservation and restoration. As increasing amounts of river restoration are undertaken, the need to understand the ecological response to different measures and where measures are best applied becomes more pressing. It is essential that appraisal methods follow a sound scientific...

Scientists and practitioners working on river restoration have made progress on understanding the recovery potential of rivers from geomorphological and engineering perspectives. We now need to build on this work to gain a better understanding of the biological processes involved in river restoration. Environmental policy agendas are focusing on na...

Multidimensional analysis of community stability has recently emerged as an overarching approach to evaluating ecosystem response to disturbance. However, the approach has previously been applied only in experimental and modelling studies. We applied this concept to an 18‐year time series (2000–2017) of macroinvertebrate community dynamics from a s...

Naleh fish Barbonymus sp. is a commercial freshwater fish, which is indigenous to Aceh, Indonesia. The population of this species has declined over the years as a result of habitat perturbations and overfishing. Hence, the crucial need to develop a cryopreservation method to support breeding programs. This involved the use of a cryoprotectant as an...

The delivery of excessive fine sediment (particles < 2 mm in diameter) to rivers can cause serious deleterious effects to aquatic ecosystems and is widely acknowledged to be one of the leading contributors to the degradation of rivers globally. Despite advances in using biological methods as a proxy, physical measures remain an important method thr...

Many members of the mullets (family Mugilidae) are very similar morphologically, hence the possibility of taxonomic misidentification. This study involved the use of skeleton structure to distinguish four species of mullets, including Cremugil crenilabis, Liza macrolepis, Moolgarda engelii, and Mugil cephalus, harvested from Aceh waters, Indonesia....

The objective of the present study was to barcode genus Barbonymus fish from the rivers of Aceh, Indonesia and establish their phylogenetic relationship. Three presumed taxa of the genus Barbonymus, referred here as Naleh, Lampam-a, and Lampam-b were investigated. The Naleh samples were collected from Nagan River in western Aceh. This presumed taxo...

Section 4.6. Aquatic Plants

Numerous tree planting initiatives have been launched worldwide, based on the idea that carbon capture by trees can help to limit global warming. A recent study estimated the additional tree canopy cover that could be established given the growing conditions in every square kilometre of land on earth that is not already forested, urbanised, or used...

This study investigates the potential for physical damage caused by suspended fine sediment on gills of three macroinvertebrate species, Hydropsyche siltalai, Ephemera danica and Ecdyonurus venosus. Macroinvertebrate cadavers were exposed to three suspended sediment concentrations (control 3.5, low 83.7 and high 404.0 mg l⁻¹) at two velocities (low...

Cryoprotectant is the crucial factor in the cryopreservation process. In general, there are two types of cryoprotectant, permeating and non‐permeating cryoprotectants. Dimethyl sulfoxide (DMSO) and egg yolk are common permeating and non‐permeating cryoprotectants respectively. Hence, the objective of the present study was to determine the best prop...

Access to food has been determined to be a factor that strongly influences the dietary intake and eating habit of indigenous people (Orang Asli, OA). This study explored food acquisition and the barriers in obtaining traditional and market foods among the Jahai subtribe (within the Negrito ethnic group) via a qualitative approach. Twenty-eight OA (...

Background: Clown loach or botia, Chromobotia macracanthus Bleeker 1852, is a popular freshwater ornamental fish. Lack of high quality broodstock and asynchronous gonad maturation are the main problem in breeding of this species. Cryopreservation is one of the methods to overcome this problem, and cryoprotectant plays a vital role in this process....

Aim Metacommunity ecology is a vibrant area of research that has received increased attention in recent years, since it provides a framework to assess the underlying dispersal‐ and niche‐based processes that create non‐random and ecologically meaningful patterns in species assemblages across the landscape. Here we set out to test for the role of di...

Land use and climate change are driving widespread modifications to the biodiverse and functionally unique headwaters of rivers. In temperate and boreal regions, many headwaters drain peatlands where land management and climate change can cause significant soil erosion and peat deposition in rivers. However, effects of peat deposition in river ecos...

Trait-based ecology has been developed for decades to infer ecosystem responses to stressors based on the functional structure of communities, yet its value in species-poor systems is largely unknown. Here, we used an extensive dataset in a Spanish region highly prone to non-native fish invasions (15 catchments, N = 389 sites) to assess for the fir...

The development of hydropower and other infrastructure that disrupts river connectivity poses a serious threat to highly endemic and genetically distinct freshwater fish species in temperate parts of the Southern Hemisphere. Such locations have been neglected in previous reviews on fish passage. Fishways have long been constructed to mitigate the i...

The construction of fishways for upstream and downstream connectivity is seen as the preferred mitigation measure for hydropower dams and other riverine barriers. Yet empirical evidence for effective design criteria for many species is not available. We therefore assembled a group of international fishway design experts and combined their knowledge...

Fish-Net: Mortality rates during downstream passage through turbines (.neta file for use in Netica).

Fish-Net: Design of nature-like bypasses for resident fish (.neta file for use in Netica).

Fish-Net: Design of technical fishways for upstream movement of migratory fish (.neta file for use in Netica).

Fish-Net: Function to combine separate mortality sources into an overall mortality rate (.R file for use in R).

Rivers and their floodplains have been severely degraded with increasing global activity and expenditure under-taken on restoration measures to address the degradation. Early restoration schemes focused on habitat creation with mixed ecological success. Part of the lack of ecological success can be attributed to the lack of effective monitoring. Th...

Una gran cantidad de datos ecológicos es generada en cada temporada de muestreo, a lo que se suma un incremento considerable de datos de eDNA en el futuro. Es así, como las herramientas tradicionales ya no serán adecuadas por si solas, debido a que generalmente son métodos para formular hipótesis no testeables (e.g. NMDS) y además se hará más frecu...

The development of hydropower and other infrastructure that disrupts river connectivity poses a serious threat to highly endemic and genetically distinct freshwater fish species in temperate parts of the Southern Hemisphere. Such locations have been neglected in previous reviews on fish passage. Fishways have long been constructed to mitigate the i...

Longitudinal river fragmentation through physical barriers is a major issue for the conservation of aquatic species in regions with intense hydropower development, such as Chile. The construction of fishways is the main mitigation strategy for maintaining connectivity for fish but development of designs suitable for a broad range of species is chal...

A humanitarian crisis in the Democratic Republic of the Congo (DRC) has resulted in 2.7 million displaced people suffering from malnutrition due to lack of availability and access to fish. Some 100,000s of the displaced people are now living in refugee settlements in neighbouring Uganda, putting pressure on natural resources and host communities....

Swimming costs (SCs) for fish have been shown to be affected by turbulence. However, this idea has not yet been implemented in habitat models, which often represent hydraulics using water velocity averaged over time and space. In this study, we analysed the habitat selection of individual juvenile Atlantic salmon Salmo salar (L. 1758) in relation t...

Classification of species sensitivity for biomonitoring has been approached under two different frameworks, using either empirical data or expert opinion. Two tools for fine sediment (i.e. clogging, colmation) biomonitoring in the United Kingdom tend towards these contrasting approaches. The Proportion of Sediment-sensitive Invertebrates (PSI) inde...

Early career researchers (ECRs) play a critical role in our increasingly knowledge-based society, yet they are the most vulnerable group in the scientific community. As a relatively young, interdisciplinary science, ecohydraulics is particularly reliant on ECRs for future progress. In 2014, the Early Careers on Ecohydraulics Network (ECoENet) was c...

Over the past few years there has been a gradual increase in the appraisal and assessment of river restoration practices. Whilst many of these have concentrated on traditional biological assessments such as richness, diversity or equitability some studies are starting to examine changes in ecological processes, such as nutrient dynamics, input of o...

Hydropower barriers are among the most conspicuous anthropogenic alterations to natural riverine connectivity, resulting in species-specific effects linked to dispersal abilities, especially swimming performance. They may present a particular problem for small-bodied 'non-sport fish', such as those that characterize the freshwater communities of te...

The decline of freshwater fish biodiversity is proceeding at an alarming and persistent rate. Given that most fish must undertake some form of migration in order to complete their life-cycle, of particular concern is the proliferation of hydropower schemes that block migration routes, as well as a variety of other barriers such as weirs and culvert...

Water contaminated with fine sediment can be a primary risk to human and ecological health. Sediment impacts are, however, complex and difficult to assess in environmental and social impact assessments, especially where timescales are short. We outline a new process-based framework - Fluvial Sediment Impact Assessment (FSIA) - designed to anticipat...

This seminar is for anyone: from those wanting to learn about Bayesian methods and how they might be relevant to their field, to those who are experienced in their application. Summary: Bayes’ theorem is a much misunderstood, often maligned and controversial concept, but all that is changing. Bayesian methods are now being embraced in every discip...

The mesoscale (10⁰–10² m) of river habitats has been identified as the scale that simultaneously offers insights into ecological structure and falls within the practical bounds of river management. Mesoscale habitat (mesohabitat) classifications for relatively large rivers, however, are underdeveloped compared with those produced for smaller stream...

Water contaminated with fine sediment can be a primary risk to human and ecological health. Sediment impacts are, however, complex and difficult to assess in environmental and social impact assessments, especially where timescales are short. We outline a new process-based framework - Fluvial Sediment Impact Assessment (FSIA) - designed to anticipat...

The mesohabitat concept has become an important part of many river research and management activities yet its theoretical foundation is weak. This work seeks to strengthen this foundation by developing a new classification of mesohabitats based on hydrodynamics. The classification uses predictor variables describing ecologically relevant aspects of...

This thesis brings together three recent trends in river research, namely the mesohabitat concept, the hydrodynamics of river ecosystems and the development of bioenergetic models, in order to drive progress in key river management applications. These applications include river habitat assessment, modelling and rehabilitation and the conservation o...

In this chapter the authors argue that the inclusion of higher order (turbulent) properties of the flow constitutes a more complete and ecologically relevant characterisation of the hydraulic environment that biota are exposed to than standard ecohydraulic variables alone. After outlining the theory, structure and measurement of turbulent flow in o...

River research and management activities often focus on mesoscale habitat (mesohabitat) classifications such as physical biotopes (e.g. pools, glides, runs, riffles). The size and surface flow characteristics of these features are such that they can easily be mapped from the bank and incorporated into rapid field reconnaissance surveys (e.g. UK Riv...

Results indicate that both absolute values and the spatial variability of turbulent flow properties could provide the basis for a classificatory framework for physical biotopes. The Principal Components of Neighbour Matrices (PCNM) analysis suggests that this is because of fundamental differences in the structuring of flow among habitats. This has...