Dry watercourses, suffering agricultural soils, forest fires… Drought has many deleterious consequences. But it also strongly disturbs wild animals, which in addition to thirst, also see their reproduction or their migrations upset by the lack of water, alerted the League for the Protection of Birds on Monday.
In the 10 natural areas managed by the LPO in Charente-Maritime and Vendée, where during the spring and summer of 2022 rainfall was 30% less abundant than the ten-year average, we “note a real loss of biodiversity: drop in reproductive success, mortality, drop in visits to sites, etc.,” underlines the association. In some areas, the consequences have been particularly devastating.
Slowed or non-existent reproduction
Thus on the nature reserves of Saint-Denis-du-Payré and Marais de la Vacherie, the numbers of migrating waterbirds were 19 times lower in August 2022 compared to the average for the previous five years, with the presence of only 64 individuals against about 1,200 birds on average. Moreover, at the start of wintering, Anatidae (ducks) were always six times less numerous than in other years, with 1,400 birds present in December compared to an average of 8,300 previously.
For some species, reproduction has been slowed down or even non-existent due to the stress linked to the lack of water. This is the case for the Black Tern, an endangered species in France and very dependent on water levels at the start of summer, where no broods were observed in 2022 on the Vacherie reserve, which concentrates the essential workforce in the Marais poitevin. No young either among the Lestes with large stigma, a species of dragonfly which is already suffering from the gradual disappearance of wetlands, and the cultriped pelobates, a toad classified as vulnerable in France, in the Moeze-Oleron reserve, due to the early drying up of watercourses.
The survival of certain “at risk” species
“For these species that do not move, it is therefore a net and dry loss” highly damaging, underlines Cédric Marteau, director of the nature protection division at the LPO. A “fairly high” fish mortality was also observed in the Oléron area, while several insects (spiders, locusts, flower-growing invertebrates) were hardly observed due to very dry conditions and flowering. low grassland. “Without water, the environment is less welcoming, food is less available, predation is stronger”, all of which have a strong impact on biodiversity, underlines Cédric Marteau.
These findings prove that “climate crises and the collapse of biodiversity are intimately linked and must be dealt with together”, notes the LPO. Combined with other pressures already weighing on wildlife (intensive agriculture, hunting, pollution, proliferation of invasive species), “drought events lasting several years in a row could directly jeopardize the survival of certain species”, adds the association. , while groundwater levels were still at their lowest at the end of March, raising fears of another dry summer in France.