Gerard Van der Velde

Radboud University | RU · Institute for Water and Wetland Research

The invasive alien false mussels Mytilopsis leucophaeata cochleata and Dreissena polymorpha (Dreissenidae) have established populations in the North Sea canal in the Netherlands that connects the harbours of Amsterdam with the North Sea. The favourable and unfavourable salinity ranges of both species were earlier studied in long-term outdoor mesoco...

Co-occurring and morphologically similar species have adapted to differential niches to minimize competition. An invasive alien species can occupy an ‘empty niche’ in introduced ranges. Alternatively, the invader may occupy an overlapping niche and compete with native species to a certain degree. In a Western European lowland brook with high nutrie...

Heavy metals are naturally omnipresent in aquatic systems. Excess amounts of heavy metals can accumulate in organisms of pollution impacted systems and transfer across a food web. Analysing the food web structure and metal contents of the organisms can help unravel the pathways of biomagnification or biodilution and gain insight in trophic linkages...

Background During a study on the outdoor floating leaf blade production of Nymphoides peltata (S.G. Gmel.) O. Kuntze (Fringed Water Lily), initial leaf blade decomposition was studied by simultaneously measuring infected, damaged and lost area of floating leaf blades. Methods Data on initial decomposition over time were collected for all leaves du...

The Rhine sculpin (Cottus rhenanus) is a benthic rheophilic fish species that is endemic to tributaries of the rivers Rhine and Meuse in North-western Europe. Little is known about its occurrence and individuals density in relation to habitat characteristics. A core population of C. rhenanus occurs in the River Geul in the Netherlands. Since the la...

Invasive alien crayfish species pose major ecological and hydrological risks globally. The red swamp crayfish (Procambarus clarkii) is one of the most widespread crayfish species worldwide. Its impacts arise from burrowing activities and lead to mobilization of soil nutrients, water safety risks by instability of dikes and erosion of banks. Increas...

Background Nymphaeid macrophytes, rooting in the sediment of water bodies and characterized by floating leaves, play an important role in wetland ecosystems. The present research deals with the effects of limited space, limited nutrient availability, water temperature and an unexpected inundation on the production, turnover and plasticity of floati...

Kees den Hartog, born in Den Helder (The Netherlands), with artistic bow tie, was a versatile aquatic ecologist. He became appointed in 1970 as extra ordinary professor in botany and general ecology at the Vrije Universiteit van Brussel (Belgium) and in 1973 as professor in the aquatic ecology at the Universities of Nijmegen and Wageningen (The Net...

Here, we investigate the shell shape variation of some closely related freshwater species of the bivalve genus Corbicula using descriptive (qualitative), geometric morphometric and traditional conchometric approaches. The combination of these different approaches allows for an effective discrimination between the species C. fluminalis, C. fluminea...

Rivers of Europe, Second Edition, presents the latest update on the only primary source of complete and comparative baseline data on the biological and hydrological characteristics of more than 180 of the highest profile rivers in Europe. With even more full-color photographs and maps, the book includes conservation information on current patterns...

Worldwide over 910 terrestrial planarian species have been described. They mainly occur in tropical and subtropical regions. In Europe, 22 alien terrestrial planarian species have been recorded over the last decades. In The Netherlands, 9 alien species have been found so far, mostly in greenhouses. Three of these species have established population...

The Rhine is a 1233 km-long pivotal river in Central Europe. Its catchment harbors about 60 million inhabitants in nine countries from the Alps to the North Sea. On most of its course, this heavily modified water body is managed in favor of industrial production, urbanization, and transport. The 1816 commission on navigability was the first Europea...

Risks and Potential Management of Invasive Crayfish Since the 1950s, nine alien crayfish species (7 from North America, 1 from Southeast Europe, 1 from East Europe/Asia) have been introduced in the Netherlands. Seven of these species have well-established populations. Their impact on biodiversity and ecosystem functioning mainly results from diseas...

Conrad's false mussel Mytilopsis leucophaeata (Conrad, 1831) and the Asian date mussel Arcuatula senhousia (Benson, 1842) are highly invasive bivalves actively spreading in the Ponto-Caspian region, which includes the basins of the Black, Azov, and Caspian seas. This study provides new records of both species from this region and gives a synopsis o...

Study of the ecology and distribution of ground water and rheophilous freshwater triclads Turbellaria, Tricladida) in The Netherlands.

Since the 1950s, nine alien crayfish species have been introduced in the Rhine-Meuse river delta. Seven species originate from North America, one from Southeast Europe and one from East Europe/Asia. Currently, at least seven species have well-established populations. Five species are listed as invasive alien species (IAS) of European Union (EU) con...

Basic information on shell dimensions, calcimass and periostracum mass, biomass, and the relation between the condition and reproduction of Mytilopsis leucophaeata was analyzed for a population in the North Sea Canal, the Netherlands. The mean dry flesh weight of individuals with a mean shell length of 12.5 mm showed a peak at the end of June. The...

Alien fish are important invaders, with a high number of species introduced outside their native range worldwide. Pathogens associated with these invaders often remain undetected, while they potentially have detrimental effects on native fish species. The topmouth gudgeon (Pseudorasbora parva), a cyprinid fish, originates from Asia and is globally...

Freshwater mussels are ecosystem engineers that provide important ecosystem functions and services, such as bio-filtration. A method for quantifying filtration capacity in rivers was developed and applied in a case study that estimated the loss in filtration services provided by invasive alien dreissenid mussels following a mass mortality event in...

The Asian cyprinid Pseudorasbora parva is considered to be a major threat to native fish communities and listed as an invasive alien species of European Union concern. Our study aims to gain evidence-based knowledge on the impact of both P. parva and its parasite Sphaerothecum destruens on native fish populations by analysing fish assemblages and b...

The initial decomposition of large floating-leaved macrophytes, such as waterlilies, can be studied by following changes in leaf damage and area loss of leaf blades tagged in their natural environment. This approach was taken in the present study to examine the initial decomposition patterns of floating leaf blades of Nuphar lutea (L.) Sm., Nymphae...

Invasive species can directly or indirectly alter (a)biotic characteristics of ecosystems, resulting in changing energy flows through the food web. This can potentially affect bottom-up or top-down control on resident species. The food web structure in the Biesbosch reservoirs (The Netherlands) was examined after recent invasions of the quagga muss...

The European Union (EU) has recently published its first list of invasive alien species (IAS) of EU concern to which current legislation must apply. The list comprises species known to pose great threats to biodiversity and needs to be maintained and updated. Horizon scanning is seen as critical to identify the most threatening potential IAS that d...

The introduction and spread of alien mollusc species is strongly related to human activities such as connecting river basins through canal construction and shipping. Economic growth has caused an increase in commercial and recreational navigation on rivers and led to the development of extensive networks of waterways. Ships alter flow velocity in l...

Since 1996, the invasive Conrad's false mussel Mytilopsis leucophaeata (Conrad) has been recorded in brackish water bodies in the Ponto-Caspian region, which includes the basins of the Black Sea, Azov Sea, and Caspian Sea. In the Azov-Black Sea basin, where the number of records is increasing, its range currently includes the Dniester, Dnieper-Sout...

While native freshwater bivalve species are declining, several alien bivalve species have become invasive, thereby impacting ecosystem functioning and services. These biodiversity changes can be attributed to deteriorated water quality, hydro-morphological alterations, and the overarching effect of global change. Therefore, a systematic assessment...

The false mussel, Mytilopsis leucophaeata originating from the Atlantic coast and Gulf of Mexico in North America invaded brackish water systems in Europe. Seasonal sessile population structure is determined by spat fall, growth, and mortality. Juvenile and adult M. leucophaeata were kept in cages in a brackish water canal to study their mortality...

1. In order to predict which species can successfully cope with global warming and how other environmental stressors modulate their vulnerability to climate related environmental factors, an understanding of the ecophysiology underpinning thermal limits is essential for both conservation biology and invasion biology. 2. Heat tolerance and the exten...

Conrad's false mussel (Mytilopsis leucophaeata) is an invasive alien bivalve species causing severe biofouling problems in cooling water systems of power and industrial plants. Settlement, seasonal shell size distribution, and growth of this bivalve species were analyzed in relation to relevant environmental factors, using monitoring data from a br...

The Chinese mystery snail, Bellamya (Cipangopaludina) chinensis, was recorded for the first time in 2007 in the Netherlands. By 2016, twelve water bodies (mostly riverine ecosystems) had been colonized by this freshwater snail. These records were the first known introductions of this alien species in the European Union (EU). Insight into the invasi...

Trophic levels (TLs) of fish were estimated on three sampling dates (March, May, and August 2006) for different fish sizes in the Cabras Lagoon (Sardinia, Italy). A temporal TL variation for Atherina boyeri, Gobius niger, and Engraulis encrasicolus was observed. In March and May, the TL ranged from 3.3 to 3.4, characterizing these species as second...

Invasive alien species (IAS) are species whose introduction or spread outside their native range threatens biological diversity, ecosystem functioning, economy, and/or public health. The recent European Union (EU) regulation on the management of IAS emphasizes the need for a consistent approach to alien species assessment that will underpin interna...

Floating leaf blades of waterlilies fulfill several functions in wetland ecosystems by production, decomposition and turnover as well as exchange processes. Production and turnover rates of floating leaf blades of three waterlily species, Nuphar lutea (L.) Sm., Nymphaea alba L. and Nymphaea candida Presl, were studied in three freshwater bodies, di...

Field data of the sites Haarsteegse Wiel and Oude Waal in 1977

Field data of the site Voorste Goorven in 1988

Invasive alien species (IAS) are considered an important threat to global biodiversity due to major ecological impacts. In 2014, the European Union (EU) introduced a regulation (EU) No 1143/2014 on the prevention and management of the introduction and spread of IAS. The first risk prioritized list of IAS of EU concern was adopted on the 3 rd of Aug...

Regulated rivers in Western Europe have rapidly been colonized by invasive alien Ponto-Caspian gobies. In particular, the round goby (Neogobius melanostomus) can reach high densities in habitats with hard substratum, such as groynes and dams made of basalt stones. High densities of Ponto-Caspian gobies negatively impact native benthic fishes. It is...

The Phyllidiidae (Gastropoda, Heterobranchia, Nudibranchia) is a family of colourful nudibranchs found on Indo-Pacific coral reefs. Despite the abundant and widespread occurrence of many species, their phylogenetic relationships are not well known. The present study is the first contribution to fill the gap in our knowledge on their phylogeny by co...

COI sequences of lost Phyllidiidae specimens

Insufficient oxygen delivery to tissues is hypothesised to limit thermal tolerance, but evidence in ectotherms is mixed. We assessed heat tolerance under hypoxia, normoxia and hyperoxia to test whether the extent in which oxygen can lower or increase heat tolerance differed with mode of respiration, comparing gill-breathing caenogastropods and lung...

The benthic stages of Dreissenidae and Mytilidae may be dispersed over long distances while attached to ship hulls. Alternatively, larvae may be transported by water currents and in the ballast and bilge water of ships and vessels. To gain insight into dispersal potential and habitat suitability, survival of the benthic stages of two invasive dreis...

Invasions by alien species may cause a decline in populations of vulnerable protected species through interference and resource competition. During the last decade, four invasive goby species of Ponto-Caspian origin have displayed rapid dispersal in The Netherlands. High densities of these species have been recorded in large rivers and hydrological...

Plakobranchus papua Meyers-Muñoz & van der Velde, sp. n. from West Papua (Papua Barat province, Indonesia), is described based on its external morphology, colour pattern, internal anatomy, radula and reproductive system. In a molecular phylogenetic study specimens of this new species were compared with those of ten candidate taxa under the name Pla...

Invasions of alien gammarid species have led to reduced abundance of many native gammarid species and earlier gammarid invaders. Intra-guild predation (IGP) has been suggested as the main mechanism causing such species displacements. This study elucidates a mechanism for species displacement that is based on competition for shelter, viz. species ex...

The government of the Netherlands is currently stimulating the development of a bio-based economy. A bio-based economy involves the use of crops for the production of materials, chemicals, fuel and energy in the form of electricity and heating. In this way biological raw materials replace fossil fuels and petro-chemical derived materials. The drive...

The government of the Netherlands is currently stimulating the development of a bio-based economy. A bio-based economy involves the use of crops for the production of materials, chemicals, fuel and energy in the form of electricity and heating. In this way biological raw materials replace fossil fuels and petro-chemical derived materials. The drive...

The government of the Netherlands is currently stimulating the development of a bio-based economy. A bio-based economy involves the use of crops for the production of materials, chemicals, fuel and energy in the form of electricity and heating. In this way biological raw materials replace fossil fuels and petro-chemical derived materials. The drive...

The government of the Netherlands is currently stimulating the development of a bio-based economy. A bio-based economy involves the use of crops for the production of materials, chemicals, fuel and energy in the form of electricity and heating. In this way biological raw materials replace fossil fuels and petro-chemical derived materials. The drive...

The government of the Netherlands is currently stimulating the development of a bio-based economy. A bio-based economy involves the use of crops for the production of materials, chemicals, fuel and energy in the form of electricity and heating. In this way biological raw materials replace fossil fuels and petro-chemical derived materials. The drive...

The government of the Netherlands is currently stimulating the development of a bio-based economy. A bio-based economy involves the use of crops for the production of materials, chemicals, fuel and energy in the form of electricity and heating. In this way biological raw materials replace fossil fuels and petro-chemical derived materials. The drive...

Background: We encountered the opportunity to study proteochemically a brackish water invertebrate animal, Mytilopsis leucophaeata, belonging to the bivalves which stem from the second half of the Cambrian Period (about 510 million years ago). This way, we were able to compare it with the vertebrate animal, the frilled shark (Chlamydoselachus angu...

To support decision making with regard to the design of measures to prevent ecological, socio-economic and public health effects, the Invasive Alien Species Team of the Netherlands Food and Consumer Product Safety Authority (Ministry of Economic Affairs) has asked for a risk analysis of Impatiens species. The risk analysis of Impatiens species and...

The European Union Regulation (EU) 1143/2014 on invasive alien species (IAS) establishes an EU-wide framework for action to prevent, minimise and mitigate the adverse impacts of IAS on biodiversity and centres around the development of a list of IAS of EU Concern. The initial list of IAS of EU concern will be based on available risk assessments com...

Acidification has led to a strong decline of species characteristic of shallow soft-water lakes. In spite of reductions in acidifying deposition, natural recovery of biodiversity is modest or even absent, suggesting that the impact of acidification is difficult to reverse. We compared recovery from acidification in non-restored and restored lakes u...

This paper presents an advanced version of the Index of Biotic Integrity (IBI), a multimetric index to indicate ecosystem health. The multimetric index has been adapted in such a way that it not only indicates overall condition but also specific causes of environmental disturbance. The newly developed index (a) uses data of tolerant as well as into...