Rediscovery of the endangered species Harpalus flavescens (Coleoptera: Carabidae) in the Loire River Olivier Denux, Emmanuelle Dauffy-Richard, Jean-Pierre Rossi, Sylvie Augustin To cite this version: Olivier Denux, Emmanuelle Dauffy-Richard, Jean-Pierre Rossi, Sylvie Augustin. Rediscovery ofthe endangered species Harpalus flavescens (Coleoptera: Carabidae) in the Loire River. Insect conserva- tion and diversity, Wiley-Blackwell, 2017, 10 (6), 7 p. 10.1111/icad.12228. hal-01605515 HAL Id: hal-01605515 https://hal.archives-ouvertes.fr/hal-01605515 Submitted on 25 May 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Distributed under a Creative Commons Attribution - ShareAlike| 4.0 International License Insect Conservation and Diversity (2017) doi: 10.1111/icad.12228 SHORT COMMUNICATION Rediscovery of the endangered species Harpalus flavescens (Coleoptera: Carabidae) in the Loire River OLIVIER DENUX,1,2 EMMANUELLE DAUFFY-RICHARD,3,† 4 1 JEAN-PIERRE ROSSI and SYLVIE AUGUSTIN 1INRA, UR 633, Zoologie Forestiere, Orleans, France, 2Entomotec, Nouan-le-Fuzelier, France, 3IRSTEA, UR EFNO, Nogent-sur-Vernisson, France and 4INRA, UMR CBGP, Montferrier-sur-Lez Cedex, France Abstract. 1. The Loire River is one of the last European large rivers with important sediment dynamics and numerous sandbanks. The extraction of sedi- ment from the riverbed during decades and the construction of levees for flood prevention have strongly affected and shaped the biodiversity of the Loire River. 2. Many species from pioneer riverbanks have been impacted with particular consequences for psammophilous insects. The ground beetle Harpalus (Acardys- tus) flavescens (Piller & Mitterpacher, 1783), is considered to have disappeared from the Middle Loire River for 40 years and is endangered everywhere in Europe. 3. In 2012 and 2013, we recorded two specimens of H. flavescens in Region Centre-Val de Loire (France), in the course of a survey dedicated to evaluating the impact of fluvial maintenance operations upon sediment and biodiversity dynamics. 4. The presence of H. flavescens may be linked to the interruption of riverbed extractions and the vegetation removal of sandbanks of the Loire River (ecosys- tem restoration). Key words. Biodiversity, ground beetles, pioneer land, sand, shore, threatened species. Introduction characteristics. These formations have a peculiar dynamics due to the hydraulic characteristics (depth, speed) and Alluvial rivers have historically been an attractive source shape of the channel (Wintenberger et al., 2015a). Some of sediment for economic development activities. But sedi- of these bars are in stable position (forced bars) while ment extractions have produced many detrimental effects, others are very mobile in flood period (free bars). Free including channel incision (sinking of riverbed), loss of and forced bars can stabilise and support pioneer vegeta- riparian habitats and several other ecological and environ- tion that can evolve to woody stages, where black poplar mental impacts (Rinaldi et al., 2005). With a length of is prevalent (Wintenberger et al., 2015b), or to more 1012 km, the Loire River is the largest river in France diversified woodland (island stage). Early stages of the and one of the last wild rivers of Europe (Bastien et al., succession correspond to pioneer sandy-gravel habitats 2009). The path of the Loire and some of its tributaries and constitute a reservoir for a large number of species often change due to an important morpho-sedimentary associated to sand. These species are referred to as ‘areni- dynamics (Claude et al., 2014; Rodrigues et al., 2015). colous’ (Torre-Bueno & Nichols, 1989; Hanson, 2007), This leads to the transportation and natural accumulation ‘sabulicole’ (Hanson, 2007) or ‘psammophilic/psam- of sediments and the formation of sedimentary bars mophilous’ (Lewis, 1977; Thiele, 1977; Torre-Bueno & (sandbars), which constitute one of the Loire River Nichols, 1989). Since the 1950s, the massive gravel extrac- tion from the Loire riverbeds (e.g. 6.4 million tonnes in 1979: see Gasowski, 1994) has caused a significant imbal- Correspondence: Olivier Denux, INRA, UR 633, Zoologie ance between the amount of sediment extracted and the Forestiere 45075 Orleans, France. E-mail: [email protected] †Deceased. quantity naturally replenished by natural deposition Ó 2017 The Royal Entomological Society 1 2 Olivier Denux et al. (Claude, 2012). Coupled with containment, it has caused (Lindroth, 1992). Adults appear and breed mostly in the incision of the Loire River and the lowering of the autumn. H. flavescens is a macropterous species (Hurka, water line during low-water periods. These events have 1996) but no flight observations have been made (Lin- led to the disconnection of hydraulic attachments (back- droth, 1992). Larvae live in sand, hibernate before the waters, islands, sedimentary bars, etc.) and more generally winter and complete their development during the next to the decrease in the active bank of the river (Latapie spring. Hence, sand exploitation has a direct impact on et al., 2014). In addition, the progressive cessation of population dynamics particularly in riverbeds where agropastoralism and bank maintenances and the reduction extractions are conducted in autumn. in exceptional winter floods have led to the gradual plant Due to its ecological specificities, H. flavescens is one of colonisation of pioneer environments (Grivel, 2008). the endangered species that are strongly affected by the At the same time, rivers and adjacent terrestrial habi- loss of sand areas and the degradation of its habitats, par- tats are impacted by eutrophication due to agricultural ticularly in the rivers of Central and Eastern Europe intensification and rising urban pressures (Smith et al., (Bohac & Jahnova, 2015). Although H. flavescens used to 1999). This has led to the modification of the composition be widely distributed in Europe (Homburg et al., 2013), it of the flora (Walker & Preston, 2006) and both herbivo- has declined and has become very rare in some regions rous and predatory insects (Haddad et al., 2000). In this (Kugler et al., 2008). Lindroth (1992) indicated that context, the Loire River has been considered eutrophic H. flavescens is very rare in Sweden, absent in Norway since at least 1980 (Minaudo et al., 2013). and Russian sector, and probably absent in Norway. In Both these phenomena have contributed to the decline Slovak and Czech Republic, it is rare and localised of pioneer sedimentary bars and to the modification of (Hurka, 1996). In Denmark, H. flavescens has not been the species communities associated with these environ- recorded since 1850 (Hansen & Jorum, 2014), in Belgium ments (e.g. loss of species richness, overgrowth of ordi- it is seriously threatened (Belgian Species List, 2015), in nary species, speeding up of the vegetation succession). Switzerland and Germany it is an endangered species The ground beetle Harpalus (Acardystus) flavescens (Trautner et al., 2005; Luka et al., 2009), and it has been (Piller & Mitterpacher, 1783) (Fig. 1a) is an emblematic observed only in some northern parts of Italy (Allegro & species of pioneer sand habitats such as continental aeo- Sciaky, 2001). In France, the species was historically pre- lian sand dunes, river sandbanks, coastal dunes, or sand- sent in the Tertiary sands of the Paris Basin, in the Loire pits. It is a steno-xerophilous species (Luka et al., 2009) and Allier basins (Jeannel, 1942; Bonadona, 1971; Velle, that lives deep in the sand, especially among roots of vari- 2004), the Seille Valley, in the Bresse and Lyonnais ous grasses, such as Corynephorus, Psamma and Panicum (Sainte-Claire Deville, 1935). It has also been observed in Fig. 1. (a) Habitus of Harpalus flavescens (copyright Olivier Denux); environment where Harpalus flavescens was found in Middle Loire River: (b) National Nature Reserve of Saint-Mesmin, Mareau-aux-Pres; (c), Baule. Red dotted line represents the favourable habitat areas of the species. Ó 2017 The Royal Entomological Society, Insect Conservation and Diversity Rediscovery of Harpalus flavescens 3 Alsace (Callot & Schott, 1993), Puy-de-Dome^ and 001°46056.3″E]). We studied other Loire River sections, Pyrenees (Tronquet, 2014) and Picardie, Nord, Hautes- located upstream in the areas of Sandillon and Saint- Pyrenees and Landes (Valemberg, 1997). H. flavescens is Denis-en-Val (see Fig. S1, a1 sector [47°51030.4″N, declining (Coulon et al., 2011) or endangered (Tronquet, 002°03007.0″E] and A2 sector [47°53014.5″N, 2014) in all areas where it exists. In the Loire Valley, H. 002°00008.9″E]) and downstream in the areas of Baule, flavescens has been considered as rare (Favarcq, 1876). In Suevres and Saint-Dye-sur-Loire (see Fig. S1, c sector Loiret department, it was reported around Gien (Victor [47°47040.7″N, 001°40052.7″E] and D sector [47°39034.2″ Pyot collection) and Orleans (Henry-Pierre Sainjon collec- N, 001°28058.5″E]). tion) until the early 20th century (Secchi et al., 2009). Ground beetles species abundance was surveyed from Currently, H. flavescens is considered to be extinct in 2012 to 2014 in five pioneer habitats of the Middle Loire Region Centre-Val de Loire (Binon et al., 2012). River: sandy formations, gravelly formations, mudflats The data reported in the present paper were collected in and cracked soil, grassland and poplar coppice. the course of a study of pioneer sediment dynamics and Ground beetles were sampled using two methods. We the associated biodiversity conducted in the Middle Loire used pitfall traps filled one-third full by 20% Mono-Pro- between 2012 and 2015 (Villar, 2015; Wintenberger et al., pylene Glycol (also called Propanediol) because it is the 2015a,b).