Ecological restoration and rewilding: two approaches with complementary goals?

As we enter the UN Decade on Ecosystem Restoration (2021–2030) and address the urgent need to protect and restore ecosystems and their ecological functions at large scales, rewilding has been brought into the limelight. Interest in this discipline is thus increasing, with a large number of conceptual scientific papers published in recent years. Increasing enthusiasm has led to discussions and debates in the scientific community about the differences between ecological restoration and rewilding. The main goal of this review is to compare and clarify the position of each field. Our results show that despite some differences (e.g. top-down versus bottom-up and functional versus taxonomic approaches) and notably with distinct goals – recovery of a defined historically determined target ecosystem versus recovery of natural processes with often no target endpoint – ecological restoration and rewilding have a common scope: the recovery of ecosystems following anthropogenic degradation. The goals of ecological restoration and rewilding have expanded with the progress of each field. However, it is unclear whether there is a paradigm shift with ecological restoration moving towards rewilding or vice versa. We underline the complementarity in time and in space of ecological restoration and rewilding. To conclude, we argue that reconciliation of these two fields of nature conservation to ensure complementarity could create a synergy to achieve their common scope

Restaurer ou réensauvager la nature ? The Conversation, mercredi 06 mars

The ConversationEn écologie comme ailleurs, les mots qui commencent par « ré » sont à la mode tels la restauration ou le réensauvagement de la nature. Ils se sont imposés, ces dernières années comme divers chemins possibles pour faire face à un problème de taille : la destruction, la dégradation, la pollution des écosystèmes et la perte de biodiversité qui en découle. Ils sont désormais des vocables débattus dans l’arène politique et utilisés par les législateurs, avec par exemple l’adoption, en juillet 2023 d’une proposition de règlement pour la restauration de la nature par le Parlement européen. Mais que décrivent réellement ces deux termes ? Sont-ils antagonistes ? Quelles visions de la nature proposent-ils

Quand l’introduction de chevaux de Przewalski en Lozère sauve l’espèce mais aussi l'environnement

https://theconversation.com/quand-lintroduction-de-chevaux-de-przewalski-en-lozere-sauve-lespece-mais-aussi-lenvironnement-23664

Quand l’introduction de chevaux de Przewalski en Lozère sauve l’espèce mais aussi l'environnement

https://theconversation.com/quand-lintroduction-de-chevaux-de-przewalski-en-lozere-sauve-lespece-mais-aussi-lenvironnement-23664

Ecological restoration and rewilding: two approaches with complementary goals?

International audienceAs we enter the UN Decade on Ecosystem Restoration (2021-2030) and address the urgent need to protect and restore ecosystems and their ecological functions at large scales, rewilding has been brought into the limelight. Interest in this discipline is thus increasing, with a large number of conceptual scientific papers published in recent years. Increasing enthusiasm has led to discussions and debates in the scientific community about the differences between ecological restoration and rewilding. The main goal of this review is to compare and clarify the position of each field. Our results show that despite some differences (e.g. top-down versus bottom-up and functional versus taxonomic approaches) and notably with distinct goalsrecovery of a defined historically determined target ecosystem versus recovery of natural processes with often no target endpointecological restoration and rewilding have a common scope: the recovery of ecosystems following anthropogenic degradation. The goals of ecological restoration and rewilding have expanded with the progress of each field. However, it is unclear whether there is a paradigm shift with ecological restoration moving towards rewilding or vice versa. We underline the complementarity in time and in space of ecological restoration and rewilding. To conclude, we argue that reconciliation of these two fields of nature conservation to ensure complementarity could create a synergy to achieve their common scope

Managed as wild, horses influence grassland vegetation differently than domestic herds

International audienceThe urgent need to preserve ecosystems over vast areas has placed rewilding with wild herbivores to the forefront. However, there are still few scientific experimental field studies dealing with its effects on biodiversity and ecosystem services. Since 1993, in France, a socially natural population of wild horses (Equus ferus przewalskii) has been managed for its conservation. This introduction is an opportunity to compare this new management system with the multi-secular extensive sheep breeding and the more recent conventional domestic horse breeding. We sought to discover if plant communities show differences depending on the grazers and the managing system. We surveyed 208 plots divided into six grazed sites (two sites per type of grazer), where all plants species and their percent cover were listed within 1m 2 , and environmental variablessuch as stones percent cover, slope-were measured within 100m 2. To focus on the grazer effects, we used a subsample of plots with similar environmental variables. To study the grazing system-management choices-effects, we ran the analyses using all the plots. At both scales, our results show that species richness, evenness and heterogeneity are significantly higher with wild horses than with sheep grazing. Intermediate value is measured for evenness concerning domestic horses at the grazing system scale. Species richness is significantly higher for domestic horses than sheep focusing on the grazer; intermediate values are measured for evenness and heterogeneity. At both scales, wild horses also favour dicots rather than monocots. Our results indicate that grazing by horses maintains and promotes grassland diversity, especially when horses are managed 'as wild'-allowing them to express their natural behaviour. However, further studies are needed focusing on populations of patrimonial plant species over time, other taxonomical groups and/or on functional diversity and ecosystem services to compare and test more finely the effects of an animal bred extensively and 'as wild'

Land cover composition, local plant community composition and honeybee colony density affect wild bee species assemblages in a Mediterranean biodiversity hot-spot

International audienceIdentifying environmental drivers which structure wild bee species assemblages appears essential in a context of worldwide pollinator decline. During a two-year survey, we studied wild bee species assemblages in an 85km 2 protected area dominated by Mediterranean scrubland, the Calanques National Park, located in southern France. Our objectives were (i) to assess the composition of the wild bee species assemblages, and (ii) to explore the effect of a) land cover composition (anthropogenic zone, low scrubland, forest and rocky land cover), b) local plant community composition, and c) honeybee colony density on wild bee species assemblages. On 17 circular 100m 2 plots, we collected 541 specimens belonging to 87 wild bee species. We found that large bee species were significantly influenced by land cover composition within a 1000m radius. More specifically, we observed that the presence of a diversified land cover composition within a 1000m radius maximized large wild bee species richness, whereas large bee abundance and richness were negatively affected by honeybee colony density. Small wild bee species were structured by the local plant community composition within 100m 2 plots and by land cover composition within a 1000m radius. Their occurrence were related to the local composition of plants growing on deep soils in scrublands. The Calanques National Park, which is the only European park located at the interface with a large city and consequently suffers from anthropic pressure, encompasses several types of land cover which are beneficial for a wide diversity of bees. However, we would like to raise awareness among park managers regarding beekeeping activities within this territory which includes diverse types of land cover favorable for wild bee species

Yellow-legged gull populations (Larus michahellis) link the history of landfills to soil eutrophication and time-related vegetation changes on small Mediterranean islands

Seabird colonies have a strong influence on both the physical and chemical soil parameters and plant communities of the islands where they settle to nest. Scientists have studied the effects of the demographic explosion of seabird populations, but few have explored the long-term effects when the colonies were in decline. The aim of this study was to investigate diachronic changes over a 24 year period of soil parameters, floristic composition and plant functionnal types (Raunkiaer growth forms and Grime life strategies) up to the decrease of the number of nesting yellow-legged gulls (Larus michahellis Naumann, 1840) on Mediterranean islands. We used 78 permanent plots to survey the vegetation and the soil parameters on 9 islands and one mainland area within the Calanques National Park (south east of France), for three periods (i.e., 1997, 2008, 2021).Since 1997, the increase of nesting gulls has caused a nitrogen and pH increase and organic carbon and C/N ratio decrease, although the values were still higher than mainland plots without nesting gulls. This has led to changes in plant species composition e.g., higher values of N favouring the development of ruderal plant species, still present in high frequency in 2021. Furthermore, plant species highly tolerant to disturbances (i.e., R Grime strategy) in harsh environments were still favoured even after the decline of gull abundance. However, both the frequency of the chamaephytes and the vegetation cover has increased with the decline of gull colony. In 2021, measures of trace elements' concentrations and calculation of pollution load index (Cu, Pb and Zn) reveals relatively low multi-contamination levels on the mainland and the archipelagos.On naturally oligotrophic and semi-arid Mediterranean islands, gull colonies induce a persistent alteration in soil characteristics that still influences plant communities (composition and functional types), 11 years after the decline in bird abundance

Pollinator Specific Richness and Their Interactions With Local Plant Species: 10 Years of Sampling in Mediterranean Habitats

International audienceIn the context of global pollinator decline, little is known about the protection status and ecology of many species. This lack of knowledge is particularly important for Mediterranean protected areas that harbor diverse pollinator communities and are subject to considerable anthropogenic pressures. Calanques National Park (85 km 2), which is located near Marseille (France), is dominated by Mediterranean low-vegetation habitats, such as phrygana and scrublands. These habitats offer favorable conditions for pollinator species due to the important amount of floral resources. Within a 10-yr period, we recorded bee (Hymenoptera: Apoidea: Anthophila), hover fly (Diptera: Syrphidae), and bee fly (Diptera: Bombyliidae) species and their interactions with the local flora through 10 field campaigns. We caught 250 pollinator species, including 192 bees, 38 hover flies, and 20 bee flies, for a total of 2,770 specimens. We recorded seven threatened bees (six near threatened and one endangered). Among the bee species, 47.9% were below-ground nesting species, and 54.7% were generalist species. Analysis of the pollination network showed that generalist and specialist pollinators do not share the same floral resources. The Cistaceae plant family (Malvales: Cistaceae) acted as a central node in the plant-pollinator network, interacting with 52 different pollinator species, which shows the importance of large open flowers that could be easily visited by both short and long-tongued pollinators in Mediterranean habitats. The occurrence of pollinator species and their ecological traits should strongly contribute to reinforcing the available information to provide or ameliorate the conservation statuses determined by IUCN Red List

Ecological and habitat restoration for insect conservation

International audienceEcological restoration, the process of assisting the recovery of an ecosystem, can benefit insect conservation. The restoration of native plant species is often associated with natural recovery of insects, firstly phytophagous and pollinators. Restoration can also specifically aim at assisting the recovery of a particular insect taxon: meadows reopened after encroachment by pine trees are suitable habitats for an endangered butterfly and the introduction of grazing, prescribed burns, and soil scraping in prairies invaded by exotic grass creates the bare ground patches essential for an endangered beetle. Restoration can also be promoted by the reintroduction of insects that are ecosystem engineers, such as ants or termites. In all cases, the recovery of insect diversity at restored sites is dependent on the level of degradation, the implemented restoration actions, the landscape and regional context, mobility of insect species, and species-specific interactions. Insects have complex life cycles: eggs, larvae, and adults do not share the same habitat requirements and are at different levels in the trophic network. As a result, restoration projects cannot provide an ideal habitat that satisfies the diverse needs of all insects. However, maximizing habitat complexity and heterogeneity is a way to provide a variety of habitats and promote insect diversity