Geert De Knijf

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Verified

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• MSc
• Senior Researcher at Research Institute for Nature and Forest

It is expected that climate change will have a great impact on many species and habitats. This will be greater if populations are found at the edge of their range or are isolated, and could lead to regional extinction. Here we investigate the possible impact on two boreo-alpine dragonfly species, Somatochlora alpestris and S. arctica, at their rang...

The Odon. fauna of Montenegro was investigated during 2 field trips in 2009 and in 2011. In all, 105 localities were visited resulting in 50 observed spp. (52 taxa). Im-portant populations of Lindenia tetraphylla and Selysiothemis nigra were found, that of the former is probably the most important one in Europe. The presence of Lestes parvidens, Ca...

The dragonfly genus Ischnura has been the subject of numerous studies and is well studied in Europe and the Middle East. Nevertheless, information on the ecology, habitat preferences and phylogenetic relationships of some species is deficient. One species lacking such data is Ischnura intermedia, a near endemic species of the Middle East, found for...

Aim Poleward range shifts of species are among the most obvious effects of climate change on biodiversity. As a consequence of these range shifts, species communities are predicted to become increasingly composed of warm‐dwelling species, but this has only been studied for a limited number of taxa, mainly birds, butterflies and plants. As species g...

Based on a distribution database brought together for the recently published Atlas of the European dragonflies and damselflies, we describe the patterns of diversity and endemism of these insect groups. Highest species richness, as well as richness of predominantly lentic species, occurs in central and western-central Europe. Strictly lotic species...

1. Dragonflies (Odonata) are ancient and familiar insects with a deep and strong cultural association with humans. They have an aquatic larval stage and an aerial adult stage, meaning that they respond to ecological conditions in both freshwater and the adjacent land surface. 2. Currently, 16% of dragonflies are threatened. Overall, they face sever...

Online portals have facilitated collecting extensive biodiversity data by naturalists, offering unprecedented coverage and resolution in space and time. Despite being the most widely available class of biodiversity data, opportunistically collected records have remained largely inaccessible to community ecologists since the imperfect and highly het...

Freshwater ecosystems are highly biodiverse¹ and important for livelihoods and economic development², but are under substantial stress³. To date, comprehensive global assessments of extinction risk have not included any speciose groups primarily living in freshwaters. Consequently, data from predominantly terrestrial tetrapods4,5 are used to guide...

This report identifies a set of priority actions needed to reverse the declines of thirty threatened dragonfly species in the European Union. It is based on data from the latest European Red List of Dragonflies and Damselflies (2024) and employs the “Assessment to Plan” methodology of the IUCN Species Survival Commission (SSC) with a specific focus...

https://www.gbif.org/dataset/2c38cf8a-f981-4dfb-bc9d-dd2b6fc792ed Waarnemingen.be / observations.be - List of species observed in Belgium is a species checklist dataset published by Natuurpunt and Natagora. Waarnemingen.be (in Dutch, managed by Natuurpunt) and observation.be (in French, managed by Natagora) are the two local Belgian subsites of the...

The Habitat- and Bird Directives are the most important tools for the European nature conservation policy. In order to protect species and habitat-types and to guarantee their survival in the long run Conservation-Objectives (Instandhoudingsdoelstellingen or IHDs in Dutch) are defined per species and habitat-type and Special Protection Zones (Speci...

The strong and rapid decline of pollinators and other insects has recently drawn attention from both scientists and the media. The main threats to insects are habitat loss and fragmentation, pesticides, climate change and invasive species (such as the Yellow-legged Hornet Vespa velutina). To halt this decline it is important to conserve and manage...

The strong and rapid decline of pollinators and other insects has recently drawn attention from both scientists and the media. The main threats to insects are habitat loss and fragmentation, pesticides, climate change and invasive species (such as the Yellow-legged hornet). To halt this decline, it is crucial to conserve and manage areas that are i...

EuropaBON EBV workflow templates The information provided here represents the EBV workflow templates collected during the EuropaBON online workshop on Essential Biodiversity Variable (EBV) workflows from 22–24 February 2023. The templates were designed to capture comprehensive descriptions about the three workflow components (data collection and s...

The information represents the EBV workflow templates collected during the EuropaBON online workshop on Essential Biodiversity Variable (EBV) workflows from 22–24 February 2023. The templates were designed to capture comprehensive descriptions about the three workflow components (data collection and sampling, data integration, and modelling) that...

New records of Leucorrhinia albifrons from Belgium. Brachytron 24: 28-30. On 14 and 16 June 2023 at two different localities in Ploegsteert (Hainaut) a male of Leucorrhinia albifrons was observed. These are the second and third observation of this species for Belgium and the first ones for the Walloon Region. There are no indications of the presenc...

Onychogomphus cazuma is an endemic gomphid of eastern Spain and one of the rarest dragonflies in Europe. We report the discovery of a population of this species at Surgencia del Tajo del Buitre, Ardales, in Málaga province, Spain. Numerous exuviae and three emerging individuals were found in early June 2023. The site consists of a seepage with perm...

Onychogomphus cazuma is an endemic gomphid of eastern Spain and one of the rarest dragonflies in Europe. We report the discovery of a population of this species at Surgencia del Tajo del Buitre, Ardales, in Málaga province, Spain. Numerous exuviae and three emerging individuals were found in early June 2023. The site consists of a seepage with perm...

International and regional legislations require authorities to report regularly on the state of species of conservation concern in their region or country (e.g., the EU Birds and Habitats Directives). Monitoring schemes for species across a variety of taxonomic groups are being set up to estimate abundance trends. In Flanders (northern Belgium), un...

In recent years, we have witnessed an increasing number of reports regarding non-native invasive crayfish in Flanders. This increase applies not only to the number of observations but also to the number of species. While several crayfish species are listed as species of Union concern sensu the EU IAS Regulation (EU1143/2014), limited initiatives ha...

Simple Summary Climate change is already affecting biodiversity and will do so even more in the future. As bioclimatic parameters, such as precipitation and temperature, directly or indirectly determine the occurrence of species, the accelerated changes in these variables could have a huge impact on species distributions. In this study, we aimed to...

First records of Orange-winged Dropwing (Trithemis kirbyi) from Belgium. Orange-winged Dropwing (Trithemis kirbyi) was observed twice in southern Belgium in the summer of 2022, being a new species for the Belgian fauna. This afrotropical species was first observed in Europe in 2003. Since then in less than 10 years it colonized much of Spain and w...

Mass reproduction of the Vagrant Emperor (Anax ephippiger) in Belgium and the Netherlands in the summer of 2019. From 7 June 2019 onwards, an invasion of the Vagrant Emperor (Anax ephippiger) was observed in much of Belgium and the Netherlands with not less than 482 individuals and 1744 individuals being observed respectively. Ovipositing behavior...

https://www.gbif.org/dataset/2c38cf8a-f981-4dfb-bc9d-dd2b6fc792ed Waarnemingen.be / observations.be - List of species observed in Belgium is a species checklist dataset published by Natuurpunt and Natagora. Waarnemingen.be (in Dutch) and observation.be (in French) are the two local Belgian subsites of the global observation.org website. The checkl...

De Knijf G., Lambrechts J. & Maes D. 2022. A new Red List of the dragonflies and damselflies in Flanders. A dramatic decline of Odonata species of bogs and heathland ponds. Natuurfocus 21(2): 52-61. [In Dutch] The IUCN Red List criteria are intended to be an easily and widely understood system for classifying species the extinction risk of species...

In dit rapport geven we voor negen taxonomische groepen (vaatplanten, amfibieën en reptielen, vissen, broedvogels, overwinterende watervogels, zoogdieren, dagvlinders, libellen en sprinkhanen en krekels) een geactualiseerde lijst van soorten die belangrijk zijn voor het provinciale natuurbehoud, -beheer en/of -beleid in Antwerpen. De gegevensbronne...

In dit rapport geven we voor negen taxonomische groepen (vaatplanten, amfibieën en reptielen, vissen, broedvogels, overwinterende watervogels, zoogdieren, dagvlinders, libellen en sprinkhanen en krekels) een geactualiseerde lijst van soorten die belangrijk zijn voor het provinciale natuurbehoud, -beheer en/of -beleid in Vlaams-Brabant. De gegevensb...

In dit rapport, dat samen met de vijf provinciale rapporten één geheel vormt, beschrijven we de procedure voor de afbakening van provinciaal prioritaire soorten, maar ook van andere soorten die voor het provinciale natuurbehoud en/of -beleid van belang kunnen zijn. Naast provinciaal prioritaire soorten sensu Bauwens et al. (2001), waarbij de soorte...

In dit rapport geven we voor negen taxonomische groepen (vaatplanten, amfibieën en reptielen, vissen, broedvogels, overwinterende watervogels, zoogdieren, dagvlinders, libellen en sprinkhanen en krekels) een geactualiseerde lijst van soorten die belangrijk zijn voor het provinciale natuurbehoud, -beheer en/of -beleid in West-Vlaanderen. De gegevens...

In dit rapport geven we voor negen taxonomische groepen (vaatplanten, amfibieën en reptielen, vissen, broedvogels, overwinterende watervogels, zoogdieren, dagvlinders, libellen en sprinkhanen en krekels) een geactualiseerde lijst van soorten die belangrijk zijn voor het provinciale natuurbehoud, -beheer en/of -beleid in Limburg. De gegevensbronnen...

In dit rapport geven we voor negen taxonomische groepen (vaatplanten, amfibieën en reptielen, vissen, broedvogels, overwinterende watervogels, zoogdieren, dagvlinders, libellen en sprinkhanen en krekels) een geactualiseerde lijst van soorten die belangrijk zijn voor het provinciale natuurbehoud, -beheer en/of -beleid in Oost-Vlaanderen. De gegevens...

Denys et al. (2022) bespreken de motivatie en algemene achtergronden van het natuurbeheer (excl. exotenbeheer) voor stilstaande wateren in Vlaanderen. In dit complement geven we een beknopt overzicht van de meer courante maatregelen die daarbij kunnen worden ingezet in de gebruikelijke werksfeer van de Vlaamse natuurbeheerder, met daarbij hun toepa...

The Red List criteria of the International Union for Conservation of Nature (IUCN) are intended to be an easily and widely understood system for classifying species at high risk of extinction. However, while the Red List may focus attention on those taxa at the highest risk, it is not a means of setting priorities for conservation measures for thei...

Nitella confervacea (Charophyta) in Flanders (Belgium): the current situation. As in much of Europe, the inconspicuous charophyte Nitella confervacea appears to have always been extremely rare in Belgium. Following 80 years without any observations, a few plants were found in a small pond in 2006, not long after it had been cleared. Not long after...

More than a decade of field surveys of Caliaeschna microstigma (Schneider, 1845), at the north-western edge of species’ distribution in Bosnia & Herzegovina, Croatia, and Montenegro recorded its presence at 135 localities, of which 107 were previously unknown. Our sampling located populations north-west of the species’ previously known range limit....

More than a decade of field surveys of Caliaeschna microstigma (Schneider, 1845), at the north-western edge of species' distribution in Bosnia & Herzegovina, Croatia, and Montenegro recorded its presence at 135 localities, of which 107 were previously unknown. Our sampling located populations north-west of the species' previously known range limit....

Based on literature data, unpublished material and the results of the year-round monitoring at selected sites island-wide by the Cyprus Dragonfly Study Group since 2013, we acquired an excellent knowledge of the diversity and status of the Odonata of Cyprus. Altogether, 37 species are on the island’s checklist. Ischnura pumilio, Aeshna affinis and...

This atlas presents, for the first time, a detailed overview of the distribution of the damselflies and dragonflies (Odonata) of West and Central Asia, an area covering nearly 8 million km². The region is not only characterized by the presence of several vast arid deserts such as the Arabian desert, Syrian desert and the Karakum but also harbors ex...

Based on a database of nearly 46,000 records (a species on a day at a location) the distribution of all 173 species of dragonflies and damselflies occurring in the 24 countries of West and Central Asia is presented. For practical reasons, Kazakhstan is not included in this atlas but Afghanistan is. Distributions are shown for two time periods: prio...

Australian Swamp Stonecrop Crassula helmsii is currently one of the most challenging invasive aquatic plants in Flanders. This article provides guidelines to practitioners for the management of this already widespread species in Flanders and aims to offer a toolkit for choosing the most suitable management strategy at the local level. We provide an...

Theidentification of key biodiversity areas (KBA) was initiated by the International Union for Conservation of Nature in 2004 to overcome taxonomic biases in the selection of important areas for conservation, including freshwater ecosystems. Since then, several KBAs have been identified mainly based on the presence of trigger species (i.e., species...

Alle Taxa Biodiversiteit Inventarisatie en 30 jaar natuurbeheer

The species monitoring programme meetnetten.be aims at collecting reliable information on priority species in Flanders. It consists of a series of monitoring schemes which were designed by the Research Institute for Nature and Forest (INBO). Species are counted by volunteers in a standardized way under the coordination of the NGO Natuurpunt. This r...

Population reductions are often used to assess extinction risk of species in the IUCN Red List. Guidelines for Red List assessments describe specific methods for calculating the amount of reduction for species with strongly fluctuating populations. Recently, an alternative approach that involves expert opinion has been suggested for calculating pop...

The biting midge Forcipomyia paludis is the only ceratopogonid species known to para-sitise Odonata in Europe. This parasite is widely distributed in the Western Palaearctic, but has only once been formally cited for one damselfly species in Belgium. However, many photographs of parasitised Odonata are stored in the citizen science website www. waa...

SUMMARY De Knijf G., Scheers K., Denys L. & Adriaens T. 2020. Exotic crayfish in Belgium: time to claw back the expansion. Natuur.focus 19(4): 156-163 [in Dutch]. Invasive alien species (IAS) are considered to be one of the major threats to biodiversity on Earth. Their negative impact is especially severe in aquatic ecosystems. Until now crayfish d...

Although considered one of the most widespread dragonflies in the world, Pantala flavescens is rarely recorded in Europe and only irregularly observed in the eastern Mediter-ranean. The first published records of P. flavescens from Cyprus date back to 1957. There are no further published records from Cyprus until 2010 when a single individual and a...

Although considered one of the most widespread dragonflies in the world, Pantala flavescens is rarely recorded in Europe and only irregularly observed in the eastern Mediterranean. The first published records of P. flavescens from Cyprus date back to 1957. There are no further published records from Cyprus until 2010 when a single individual and a...

ABSTRACT Invasive non-native species represent a major problem for the biodiversity and management of nature reserves and vulnerable habitats. Their control is often difficult and requires knowledge of the species in question, as well as of target and non-target effects of possible actions, next to considerable perseverance of the manager and a fr...

In this paper we report the presence of Aeshna isoceles for the first time from Cyprus. Five males were observed and photographically documented in May 2012 in a small valley below Rizokarpaso on the Karpasia peninsula. This was, however, not followed up at that time. The species was rediscovered by members of the Cyprus Dragonfly Study Group (CDSG...

This report describes the protocol for the monitoring networks of spiders in Flanders (the Ladybird Spider - Eresus sandaliatus and the Raft Spider – Dolomedes fimbriatus). The Ladybird Spider will be monitored using transects or integral counts within delimited areas, on which webs will be counted. For the Raft Spider, a more complete survey needs...

On 9 June 2016 a male of Leucorrhinia albifrons was observed near an oligotrophic fen in the Maten in Genk-Diepenbeek. A male, probably the same individual was resighted on 11 and 12 June at the same locality. Although the site and its surroundings were properly surveyed the next days the individual was not seen again until the 19th of June 2016. N...

We report the first records of Orthetrum albistylum for Belgium at six different locations. The species was observed with one individual at four locations (Averbode, Etalle, Lavaux-Sainte-Anne, Neerpelt) in 2016, one in 2017 (Ethe), one in 2018 (Etalle) and at two locations (Etalle, Wanlin) in 2019. Proof of successful reproduction was only detecte...

Dealing with spatially explicit information at a regional level requires a unique geographic reference framework. This was missing for stagnant waters in Flanders (Belgium), mainly because existing GIS layers were insufficiently accurate or did not include many small water bodies. Therefore, the new GIS layer ‘Watervlakken’ was compiled, providing...

English abstract This report describes the protocol for the dragonfly monitoring network in Flanders (Belgium). We list the species that need to be monitored and the methods to do so. Three easily observed species of dragonfly (Calopteryx virgo, Coenagrion pulchellum and Aeshna isoceles) are counted using dragonfly-transects. We explain how the sam...

By realising the conservation objectives for European habitats it is assumed that a large number of species will benefit from these measures as well. In this analysis, we test this hypothesis for 142 species of conservation priority in Flanders. To do so, we use the potential habitat approach, i.e. mechanistic models that translate the ecological p...

Each Member State needs to report every 6 years (2013-2019, 2025…) to the European Commission (EC) about the conservation status of habitats and species present in each biogeographical region. This document presents the reporting files for the different herpetofauna species (amphibians, reptiles) for the period 2013-2018 of the species present in F...

Each Member State needs to report every 6 years (2013-2019, 2025…) to the European Commission (EC) about the conservation status of habitats and species present in each biogeographical region. This document presents the reporting files for the different bat sepcies for the period 2013-2018 of the species present in Flanders (northern Belgium). The...

Each Member State needs to report every 6 years (2013-2019, 2025…) to the European Commission (EC) about the conservation status of habitats and species present in each biogeographical region. This document presents the applied method and results for the period 2013-2018 of the species present in Flanders (northern Belgium). Flanders is nearly comp...

Each Member State needs to report every 6 years (2013-2019, 2025 …) to the European Commission (EC) about the conservation status of the Habitat Directive habitats and species present in each biogeographical region. This document presents the reporting files for the different non-flying mammals for the period 2013-2018 of the species present in Fla...

Each Member State needs to report every 6 years (2013-2019, 2025…) to the European Commission (EC) about the conservation status of habitats and species present in each biogeographical region. This document presents the reporting files for the different insect sepcies (beetles, dragonflies, butterflies) and molluscs for the period 2013-2018 of the...

Each Member State needs to report every 6 years (2013-2019, 2025…) to the European Commission (EC) about the conservation status of habitats and species present in each biogeographical region. This document presents the reporting files for the period 2013-2018 of the fish species present in Flanders (northern Belgium). The criteria used for data co...

Vooraleer de monitoring te kunnen aanvatten moet de kennis over de verspreiding van 4 soorten mollusken voldoende zijn om een goed steekproefkader te kunnen opstellen. Vooral voor de Nauwe korfslak (Vertigo angustior), de Zeggekorfslak (Vertigo moulinsiana), de Platte schijfhoren (Anisus vorticulus) en de Bataafse stroommossel (Unio crassus) dient...

SUMMARY On 18 July 2017 a population of Trithemis kirbyi Selys, 1891 was found at the Ribeira de Asseca in Tavira, Algarve, Portugal. In addition to adult males a newly emerged male was seen. This is the first proof of reproduction of T. kirbyi in Portugal and the third record for the country. RESUMEN El 18 de Julio de 2017, una población de la es...

Recent observations and status of the Yellow Clubtail (Gomphus simillimus) in Belgium and northern France. A male of the Yellow Clubtail (Gomphus simillimus) was observed at the river Chiers where it forms the border between Belgium (Torgny) and France (Velosnes). This is the sixth observation of this species for Belgium and the first for the Frenc...

This annual report provides a summary of the status of the indicators concerning the European Biodiversity Strategy targets. For Target 1, the conclusions at the Flemish level are in line with the EU Mid Term Review. For example, a small number of habitats and species of the Habitat Directive are improving slightly, but the majority are still in...

field trips were carried out in the United Arab Emirates (UAE) and the Sultanate of Oman in autumn 2010, late winter 2013, spring 2014, autumn 2014, spring 2015 and spring 2016. We recorded 37 species at 87 localities, including new localities for some species of regional interest. Information on all observed Odonata species was recorded including...

Six field trips were carried out in the United Arab Emirates (UAE) and the Sultanate of Oman in autumn 2010, late winter 2013, spring 2014, autumn 2014, spring 2015 and spring 2016. We recorded 37 species at 87 localities, including new localities for some species of regional interest. Information on all observed Odonata species was recorded includ...

This report describes the monitoring networks for the mammals European hamster (Cricetus cricetus), Common dormouse (Muscardinus avellanarius), European badger (Meles meles) and European otter (Lutra lutra). The aim of the monitoring is to obtain a population trend estimate on a Flemish scale. Common dormouse is counted annually along transects. Eu...

This article presents sites identified as Freshwater Key Biodiversity Areas (KBAs) in the Mediterranean Hotspot which are important for threatened Odonata species. The article also introduces the recently launched IUCN Global Standard for the identification of KBAs and how it can be applied as a conservation tool for freshwater species.

Nature policy and management often uses threatened and regionally important species as tools or goals. Knowledge about their ecology and distribution is, therefore, crucial to scientifically underpin conservation measures. Apart from known observations, sites where the focal species is not (yet) observed or sites where potentially suitable ecologic...

Dit document geeft weer hoe de inhaalslag voor het Vliegend hert (Lucanus cervus) en de Roestbruine kniptor (Elater ferrugineus) moet verlopen om het steekproefkader voor de monitoring van deze soorten vast te leggen. Voor beide soorten kijken we eerst op de schaal van de ecodistricten of er al voldoende kennis is over de verspreiding van de soorte...

In Europe, there are several national or regional odonatological societies and many of them publish their own journal or bulletin. Some of them have been doing so for 20 or 30 years, sometimes even longer. Others are fresh newcomers reflecting the increased interest in dragonflies in some countries. Here we give an overview of the diversity of nati...

SUMMARY Westra T, De Knijf G, Ledegen H, De Bruyn L, Maes D, Onkelinx T, Piesschaert F, Vanreusel W, Van Elegem B, Pollet M & Quataert P. 2016. Monitoring priority species in Flanders. Implementation of new monitoring schemes. Natuur.focus 15(4): 156-165 [in Dutch] Reliable information on the status and trends of species is needed to support natur...

The Lilypad Whiteface (Leucorrhinia caudalis) has been rediscovered in Flanders after an absence of more than a century. The first individual, a female, was observed on 28 May 2013 at Lommel, soon followed by a second observation of a female on 8 June at Den Diel in Mol. The next year, a male was noted on 12 and 13 June 2014 at the same locality in...

This report describes the protocol for the monitoring of grasshoppers in Flanders. We present the species that have to be monitored and the field protocol. The Saddle‐backed Bushcricket Ephippiger ephippiger must be monitored by counting the number of singing males. The Lesser‐mottled Grasshopper Stenobothrus stigmaticus is monitored by capturing a...