Olivier Lorvelec

French attempts to eradicate non-indigenous mammals and their consequences for native biota

Many European politicians, managers, and scientists believe that non-indigenous species cannot be eradicated and that attempts to do so are hazardous because of frequent undesirable results. This notion seems to be based on the view that successful eradications undertaken in many other parts of the world cannot be generalised. To allow reasoned consideration of this argument, the eradication of non-indigenous vertebrate species performed in the French territories (European and overseas) and their recorded consequences on native fauna and flora are synthesised. Nineteen vertebrate eradication attempts were recorded, with seven mammal species as the targets. Of these attempts four failed for technical reasons and one for reasons undetermined as yet. These operations took place on islands of four biogeographical areas (West-European, Mediterranean, West Indies and Indian Ocean subantarctic) except a continental one (West-European continent). Among these 19 attempts, 13 were conducted according to a global strategy that provided data on the impact of the disappearance of the non-indigenous species on several native species. This impact, never detrimental, was determined for 14 species (one mammal, nine birds, one marine turtle, one crab, one beetle, one plant). Unexpected consequences of the disappearance of the invader were recorded for four native species (29%). This result highlights the poverty of natural historical information for several taxa and the flimsiness of the empty niche concept that is often used to argue for the delay of or to prevent any action again a non-indigenous species. If French territories can be taken as an example, eradications of non-indigenous species are not impossible; a good risk assessment prevents undesirable long-term consequences for native species and several native species benefited from the disappearance of the invader. Furthermore, eradication constitutes a powerful experimental tool for ecology and natural history studies if conceived as both a management and research operation.

Field sampling of the tick Amblyomma variegatum (Acari: Ixodidae) on pastures in Guadeloupe; attraction of CO2 and/or tick pheromones and conditions of use

Field experiments were conducted in Guadeloupe to evaluate the attraction of different chemicals on a Guadeloupean strain of Amblyomma variegatum. Such tick sampling techniques may help to assess the size of the tick population on pastures before, during and after an attempted tick eradication campaign. CO2 was absolutely necessary to activate ticks, including the larvae. In addition to activation, our data suggested that CO2 itself is attractive for ticks. The reactivity of the ticks varied greatly with the period of the year, the adults being insensitive to CO2 alone or combined with pheromones for a period extending from December to June. For the whole period, the total captures were equal for the males and females, but the males were relatively more sensitive at the beginning of the season of activity (June–July), while the females dominated, but not significantly, for the rest of the period. There was also a gradient of reactivity depending on the distance from the trap; 28% of the ticks were captured at 0.5 m from the CO2 traps and 1.2% at a distance of 6 m. The ticks arrived rapidly at the trap. After 1 h of trapping, 55, 68 and 81% of the active nymphs, males and females, respectively, had reached the trap. Synthetic pheromones (methyl salicylate, o-nitrophenol and nonanoic acid in the proportions 1:2:8) or freshly detached males added to CO2, greatly increased the efficacy of the CO2 traps. Depending on the concentration of the pheromones, the attraction was four to 70 times higher than with CO2 alone. The effect depended on the sex of the ticks, males being attracted in a greater proportion by small amounts of pheromones, while the females were activated by higher doses. From a practical point of view, sampling should be conducted from June to December, with CO2 and high concentrations of pheromones, the traps being in operation for approximately 1 h at least, the area concerned by effluents being located downwind and covering an area of approximately 36 m2.

Amphibians and reptiles of the French West Indies: Inventory, threats and conservation

At least five marine turtles and 49 terrestrial or freshwater amphibians and reptiles have been listed from the French West Indies since the beginning of human settlement. Among terrestrial or freshwater species, two groups may be distinguished. The first group comprises 35 native species, of which seven are currently extinct or vanished. These species are often endemic to a bank and make up the initial herpetofauna of the French West Indies. Disregarding two species impossible to rule on due to lack of data, the second group includes twelve species that were introduced. Except for marine turtles and some terrestrial species for which the decline was due to human predation, the extinctions primarily involved ground living reptiles of average size and round section body shape. Habitat degradation and mammalian predator introductions have probably contributed to the extinction of these species, in addition to a possible direct impact of man. To better understand the threats to species, we suggest studying the interactions between native herpetofauna and introduced competitors or predators, taking into account the habitat structure. This would help to give the necessary information for successful management measures for conservation or restoration. As an example, the conservation of the Petite Terre (Guadeloupe) Iguana delicatissima population requires identifying both the mechanisms that regulate its population and their relationships to catastrophic climatic events.

Eradications as scientific experiments: progress in simultaneous eradications of two major invasive taxa from a Mediterranean island

BACKGROUND Black rats, Rattus rattus, and mat-forming iceplants, Carpobrotus aff. acinaciformis and Carpobrotus edulis, are pervasive pests on Mediterranean islands. Their cumulative impacts on native biotas alter the functioning of island ecosystems and threaten biodiversity. A report is given here of the first attempt to eradicate both taxa from a protected nature reserve in south-eastern France (Bagaud Island). In order to minimise unwanted hazardous outcomes and produce scientific knowledge, the operations were embedded in a four-step strategy including initial site assessment, planning, restoration and monitoring. RESULTS Trapping, which resulted in the removal of 1923 rats in 21 045 trap-nights, made it possible to eliminate a substantial proportion of the resident rat population and to reduce the amount of rodenticide delivered in the second stage of the operation. Forty tons of Carpobrotus spp. were manually uprooted from a total area of 18 000 m(2) ; yet careful monitoring over a decade is still required to prevent germinations from the seed bank. CONCLUSION Two years after the beginning of the interventions, both eradication operations are still ongoing. Biosecurity measures have been implemented to reduce reinvasion risks of both taxa. With the long-term monitoring of various native plants and animals, Bagaud Island will become a reference study site for scientific purposes.

The precautionary principle and biological invasion: the case of the House Sparrow on the Lesser Antilles

The capacity to react quickly to species introductions and to plan effective management countermeasures is always difficult, and methodology is lacking. This paper summarizes the different steps of a decision-making protocol applied to the recent establishment of an exotic species, the House Sparrow Passer domesticus, in the Lesser Antilles. This pest bird damages crops, fruits and stored food products and also competes with numerous hole-nesting birds in a large part of its range, and this requires more or less rapid management decision to limit its impact. In order to construct a base for decision-making in the Lesser Antilles case, we designed and conducted a brief biological study involving three spatial scales. At the regional scale, we defined the state of spread of House Sparrows throughout the West Indies. At the island scale, we estimated the number and distribution of breeding colonies. At the local scale, we estimated the numbers and behaviour of House Sparrows. To enable a quick decision to be made, we also suggested organizing a collective decision-making process applying a multi-actor guideline taking account of the different kinds of actors and levels of competence. We applied this method and we presented our results to a multi-actor workshop. The collective decision-making chose to apply the precautionary principle on one island (bird eradication) and to install both communications and monitoring plans. The procedure involving both multi-spatial scale assessment and a multi-actor workshop needs to be refined but its prospects are promising.

Holocene turnover of the French vertebrate fauna

Comparing available paleontological, archaeological, historical, and former distributional data with current natural history and distributions demonstrated a turnover in the French vertebrate fauna during the Holocene (subdivided into seven sub-periods). To this end, a network of 53 specialists gleaned information from more than 1300 documents, the majority never cited before in the academic literature. The designation of 699 species as native, vanished, or non-indigenous in France or in one or more of its biogeographical entities during the Holocene period was investigated. Among these 699 species, 585 were found to belong to one or more of these categories. Among the 154 species that fit the definition of non-indigenous, 86 species were new species for France during the Holocene. Fifty-one that were autochthonous vanished from France during this period. Among these 51 species, 10 (two birds and eight mammals) are now globally extinct. During the last 11 millennia, the turnover in the French vertebrate fauna yielded a net gain of 35 species. On a taxon-by-taxon basis, there was a gain in the sizes of the ichthyofauna (19 : 27%), the avifauna (10 : 3%) and the herpetofauna (7 : 9%) and a loss in the mammalian fauna (−1 : 1%). Values of a per-century invasion index were less than 1 between 9200 BC and 1600 AD but increased dramatically after this date. An exponential model fits the trajectory of this index well, reaching the value of 132 invasions per century for the last sub-period, which encompasses 1945–2002. Currently, the local ecological and economic impacts of populations of 116 species (75% of the 154 that satisfied the criteria for non-indigenous) are undocumented, and the non-indigenous populations of 107 vertebrate species (69%) are unmanaged. The delay in assessing the ecological and economical impact of non-indigenous species, which is related to a lack of interest of French academic scientists in the Science and Action programmes, prevents the public from becoming informed and hinders the debates needed to construct a global strategy. For such a strategy to be effective, it will have to be elaborated at a more global scale than in just France – definitely at least in Europe.

A New Digital Map of Limits of Oceans and Seas Consistent with High- Resolution Global Shorelines

ABSTRACT Fourcy, D. and Lorvelec, O., 2013. A new digital map of limits of oceans and seas consistent with high-resolution global shorelines. We present a vector map of the limits of oceans and seas intended to be integrated into a geographic information system (GIS). This map is based on the document S-23 titled “Limits of Oceans and Seas” and published by the International Hydrographic Organization (IHO). The third edition of this document, published in 1953, still serves as an official reference. The realization of this map from a text containing numerous ambiguities, disused place-names, or imprecise coordinates required important documentary investigations. This was made possible through the use of online resources such as map libraries, satellite imageries, geographic names databases, and institutional geoportals. The main innovations of our map are its accuracy, its precision of about 10 s of meridian arc, and its consistency with the Global, Self-consistent, Hierarchical, High-resolution Shoreline database and with satellite images such as Land Satellite and moderate-resolution imaging spectroradiometer. All remaining uncertainties for the drawing of limits are presented in the results. Although based on an IHO document, our map does not possess any official status. Nevertheless, we hope that our map will facilitate and encourage more detailed spatial analyses related to oceans and seas. This map is freely available for noncommercial use.

Habitat use and potential interactions between the house mouse and lesser white-toothed shrew on an island undergoing habitat restoration

To forecast the potential impact of plant community and dry-stone wall restoration on an insular population of the lesser white-toothed shrewCrocidura suaveolens Pallas, 1811, shrew and house mouseMus musculus Linnaeus, 1758 abundances were assessed in 3 anthropogenic habitats on Béniguet Island, Brittany, France, by a standardised annual trapping system checked yearly for 9 years and in 6 “natural” habitats by trap-lines. The standardised trapping system showed that abundances of both species fluctuated synchronously for nine years, suggesting that interactions between the species had little impact if any on abundances. Mice were trapped in all habitats, but shrews only in “stone” habitats except for rare occurrences in one damp depression. Ruderal habitat was rarely used by either species. Data suggest that on Béniguet Island: (1)M. musculus is associated with anthropogenic habitats but is not as strictly tied to them as at nearby continental sites; (2)C. suaveolens is synanthropic, as has been reported in continental northern France; (3) shingle beaches and seashore food resources are particularly important forC. suaveolens; (4) the relationship betweenC. suaveolens andM. musculus could not be determined by the experiments and, if it exists at all, appears to be more competitive than predatory. Grassland restoration is unlikely to affect shrew populations. Dry-stone wall restoration may temporarily affect shrews but should ultimately benefit them.

Skinks occur on Terre-de-Bas, Les Saintes (Guadeloupe, French West Indies)

Native skinks (Squamata, Mabuyidae) of the Caribbean islands are threatened with extinction because of the introduction of the Small Indian Mongoose (Urva auropunctata) and many species have been extirpated from portions of their range, or have disappeared entirely (Hedges and Conn, 2012). For this reason, observations of surviving skink populations are important for conservation purposes. Les Saintes is a Guadeloupean micro-archipelago, located south of Basse-Terre and comprising two main islets, Terre-de-Bas and Terre-de-Haut. They are 850 meters apart and 6.8 and 6.0 km2 in area, respectively, with several smaller islets. The Small Indian Mongoose is absent from Les Saintes. The first mention of skinks in Les Saintes was by Lazell (1973) who noted their presence without detail of date, islet, or circumstance. The recent (2014) discovery of a small (5 individuals) skink population on Terre-de-Haut of Les Saintes (Angin et al. 2015; Angin & Gomès 2015) and the discovery of a specimen collected in 2010 on Terre-de-Bas of Les Saintes and preserved in rum (Angin et al. 2015, Gomès & Ibéné 2015) confirm that skinks occur in Les Saintes. After these recent reports, and because skinks have not been observed previously on Terre-de-Bas of Les Saintes despite regular visits, the possibility arose that they may no longer occur on that islet. However, finding skinks, especially when rare, is often difficult, and deciding if they are present or have disappeared is a challenge. During July 2016, we slowly walked the trails of Terre-de-Bas to search for skinks, covering a total of 34 km in 22 hours, during mornings (07:30–11:30), in forests and in open and mixed habitats. On July 9th we went through old pastures and cotton-indigo fields covered with Sporobolus grass and scattered with blocks or piles of stones, in the process of recolonization by the native tree species Guettarda scabra, Tabebuia heterophylla, and Coccoloba uvifera

A new species of skink from the Guadeloupe Archipelago (Squamata, Mabuyidae, Mabuya)

A new species of lizard of the genus Mabuya is described from a small island in the Guadeloupe Archipelago: Terre de Bas, Iles de la Petite Terre. Mabuya parviterrae sp. nov. is allied with the other four species of Mabuya from Guadeloupe. However, it differs in scalation, coloration, and (where available) DNA sequence. Of the nine named species in the genus, only M. dominicana (from Dominica), M. desiradae (from La Desirade), nd M. parviterrae sp. nov. have escaped decimation and possible extinction by the Small Indian Mongoose, Urva auropunctata. The latter two species of skinks are critically endangered, being threatened by the Black Rat (Rattus rattus) and degraded habitat that has not recovered from early land use. The Petite Terre Skink probably has one of the smallest distributions of a vertebrate species. The species consists of approximately 50 individuals living primarily in a dry stone wall of less than 500 square meters in extent.