Twenty-year research project reveals ‘devastating loss’ of Irish flora – The Irish Times

More than half of Ireland’s native plants are in decline, according to a 20-year study, while many of the habitats on which Irish wild plants depend have been destroyed or altered by agriculture and forestry since the 1950s.

The findings are detailed in the latest plant atlas produced by the Botanical Society of Britain & Ireland (BSBI) and released on Wednesday.

In particular, the largest survey of plant life on the island of Ireland to date confirms “the devastating loss of Ireland’s wild plants”. Almost 3 million plant datasets were fed into the project.

Its authors describe it as “the most meaningful assessment ever made of the condition of our wild and naturalized plants.”

It shows a 56 per cent decline in range or abundance – and often both – in Ireland’s native plants, with native grassland plants suffering the most, while 80 per cent of non-native plants introduced since 1500 have increasingly come to dominate the landscape.

In addition, many plants in lakes and wetlands have also declined, indicating increasing pressure on these habitats, according to the Plant Atlas 2020.

Loss of grassland species is most pronounced in areas of intensive agriculture, while loss of marine and freshwater species is largely due to runoff pollution in the form of excess nutrients – that from farms near watercourses, poorly treated wastewater and discharges of raw sewage.

Most of the increasingly obvious non-native species are benign, but a few, such as

Overseeding, over-fertilization of land, nitrogen inputs, herbicides, soil drainage and changes in grazing pressure have all contributed to the decline of species like agrimony, field gentian, marsh lousewort and many others, he adds.

The decline of grasslands is particularly evident in the south and east due to intensive dairy farming and tillage – with ‘clean seeds’ wiping out ancient plant species known as archaeophytes.

Lakes and wetlands have been badly affected since the last atlas was produced; “Some lakes are now dominated by the few aquatic plants that benefit from the nutrient enrichment, such as the introduced pondweed.”

Many peat bogs have been planted with conifers or used for agriculture, with the exception of native bog plants such as heather and sundew, it finds.

Peatland habitats are important for carbon storage and their restoration is essential as part of efforts to combat climate change. There is evidence that climate change may have affected Irish flora by helping some southern species spread north. A number of orchids and once-common species such as cowslip are rarely observed.

The Plant Atlas 2020 is the most comprehensive survey of British and Irish flora ever undertaken. It builds on two previous Atlas surveys conducted by BSBI. In Ireland nearly 3 million plant records of 1,939 species have been collected by 2,500 people including botanists, scientists and trained volunteers.

BSBI President Dr. Micheline Sheehy Skeffington said: “The Plant Atlas 2020 is a tremendous achievement, but it must be seen as a wake-up call to action. Plants are the basis of all biodiversity.”

She added: “The results of this unprecedented survey will inform our governments and help strengthen their work to conserve plants and the habitats they depend on. We also work with the general public by providing training and resources to help people learn more about Ireland’s wild plants.”

BSBI Head of Science Dr. Kevin Walker, a co-author of the atlas, said there are many ways to reverse flora decline, “but the most important are to increase protection for plants, expand the habitat available to them, and put their needs at the heart of the environment.” nature protection”.

“We also need to ensure that our land, water and soil are managed more sustainably so that plants and the species that depend on them for food and shelter can thrive,” he added.

“It is a snapshot of the status of all of our wild flora on these islands. It provides a basis for plans to better conserve plant species and their habitats, with a focus on those most at risk,” said Dr. Sheehy Skeffington.

“The stark reality is that 56 percent of our native species have declined since records began for the second atlas in 1987.” The decline is worse than the UK, which is 53 percent.

By comparing abundance and diversity within 10 x 10 km squares in 2000, current figures are derived and mapped for the atlas.

dr Sheehy Skeffington highlighted some worrying trends, including the decline of Parnassus grass, which is not a grass but an attractive flower. This fen species likes moist, calcareous or calcareous habitats and its occurrence in Ireland has declined dramatically since 1987. It is an “indicator species” whose demise indicates a dwindling habitat – in this case marshland. “The drainage of these often hidden wetlands and seeps has resulted in the decline of residents like this species.”

The field gentian has also declined sharply. It grows in grassy heathlands and will not survive soil enrichment or heavy grazing.

Other species falling are orchids, which are sensitive to nutrient build-up, particularly the fly orchid and large butterfly orchid, “but which are so special when we find them, usually in wetter heathland.” But all of this will be stifled when grazing is abandoned and the shrubs return. Low-intensity farming is essential to sustain it.”

The latest data means that distributions and trends for a number of associated species can be combined to identify spots across the island where habitats and their plants are most threatened.

“In some cases, such as in lakes and rivers, this can be reversible in the long term as it is due to increased nutrients and runoff of mud or peat into the watercourses. This can and should be addressed locally as many of the more sensitive species such as the rare slender naiad have declined dramatically,” she said.

Many lakes are “almost devastated” from a species mix perspective, notably Lough Leane in Co Kerry and Lough Derg on the Shannon, which are in very poor condition, she said.

dr In many cases, Sheehy Skeffington highlighted the inadequate response by the Department of Agriculture and not by farmers to species declines.

The department needs to work more closely with the National Parks & Wildlife Service “to support farmers, who are custodians of our landscape, in conserving our wild habitats,” she added.

“Plant species define a habitat and form the basis of all life. Losing them will result in the loss of many more insects and other species… Farmers know the country better than anyone. Therefore, it is crucial to work with them towards a result-oriented system.”

This requires working towards the goal of “highest possible biodiversity on a field basis” and the farmer being paid proportionately for achieving this goal, with increments based on higher results.

“It has received international recognition and awards in the Burren Farming Program – and it has really worked,” she said. “Not only does it work well for the farmers, but for the community as a whole.”

Of the 1,939 plant species recorded in Ireland, 952 were native. Among 987 non-natives, 890 were recent introductions, many originating from gardens and then spreading to establish self-sustaining populations, while 97 were ancient (pre-1500) introductions.

Minister of State for Heritage Malcolm Noonan will officially launch the atlas at Dublin’s National Botanic Gardens on Thursday. The Ireland’s Changing Flora report summarizes the key findings of the Atlas and trends affecting the current state of Ireland’s flora, assessing changes since the 1950s and analyzing drivers of change such as habitat loss, pollution and climate change.

The BSBI distribution database now contains more than 50 million plant records, making it one of the world’s largest databases of biological records.