Decline of a protected coastal pine forest under impact of a colony of great cormorants and the rate of vegetation change under ornithogenic influence

Abstract

Highlights• We studied vegetation and its changes in a pine forest affected by a colony of great cormorants.• Vegetation in the colony varied according to the period of bird influence and the stand elevation above sea level. • Considerable vegetation changes occur in several years after bird colony establishment.• Pine forest ecosystem cease to exist following a decade of bird activity. AbstractWe investigated the impact of a colony of great cormorants on the vegetation of the old growth Pinus sylvestris L. forest on the Curonian Spit peninsula, Lithuania. We studied the characteristics and rates of plant cover changes under varying length and intensity of bird influence. Plant species numbers, as well as the coverage of plants with different ecological requirements, varied according to the period of bird influence, but the resulting vegetation also depended upon the stand elevation above sea level. In our study, the initial increase in plant species richness at the start of bird nesting was not obvious and was of a transient character, due to the weak invasion of non-forest species and the rapid decline of forest plants. The colony area showed obvious and rapid vegetation changes during the investigation period. According to the calculated colony expansion rates, after 6-7 years of impact from birds the tree layer decreased by about four fold; the shrub layer decreased by about two fold; the field layer decreased by about 15 fold; and the dwarf shrub and bottom layers disappeared. The coverage by oligotrophic species decreased by more than four fold, while the coverage by eutrophic species increased by more than 60 fold. After 9-10 years of ornithogenic impact, all the trees were dead, and the protected coniferous forest ecosystem, with its characteristic plant species, had ceased to exist as such.

The impact of Grey Heron (Ardea cinerea L.) colony on soil biogeochemistry and vegetation: a natural long-term in situ experiment in a planted pine forest

“…Thus, the investigated Grey Heron colony appears a prominent natural in situ experiment unfolding the changes in an engineered ecosystem in response to the excessive deposition of both biogenic elements (N, P) and toxic organics in the soil, as well as considerably reduced pH values compared to the presumably unaffected surrounding forest area. The above conditions are representative for both natural areas occupied with birds (Goc et al, 2005;Hobara et al, 2005;Kameda et al, 2006;Adamonytė et al, 2013;Klimaszyk et al, 2015;Klimaszyk and Rzymski, 2016;Guo et al, 2018;Matulevičiūtė et al, 2018;Veum et al, 2019;Al Shehhi and Muzaffar, 2021;Machač et al, 2022;Valkó et al, 2022) as well as agricultural environments (Bradbury et al, 2005;Minkina et al, 2022). Accordingly, considering the emergence of the bird colony around 2006 and its further expansion as an experimental input, one can currently observe an engineered ecosystem with accumulated alterations in soil biogeochemistry and consequent impact on the trees and other surrounding vegetation as an endpoint of a 15-year long natural experiment.…”

“…Large bird colonies occupying relatively compact areas deposit excessive amounts of nutrients (Frederick and Powell, 1994;Ashworth et al, 2020), leading to considerable alterations in the soil geochemistry and microbiota, affecting the surrounding vegetation, and thus altogether considerably altering the local ecosystems (Sekercioglu, 2006;Whelan et al, 2015;Natusch et al, 2017;Lowney and Thomson, 2021;Grant et al, 2022;Hawke, 2022;Lowney and Thomson, 2022). For example, the impact of large birds like cormorants (Phalacrocorax carbo), Adélie penguins (Pygoscelis adeliae), Eurasian Crane (Grus grus) and Grey Heron (Ardea cinerea) has been intensively studied (Goc et al, 2005;Hobara et al, 2005;Kameda et al, 2006;Adamonytė et al, 2013;Klimaszyk et al, 2015;Klimaszyk and Rzymski, 2016;Guo et al, 2018;Matulevičiūtė et al, 2018;Veum et al, 2019;Al Shehhi and Muzaffar, 2021;Machač et al, 2022;Valkó et al, 2022). These birds form large colonies on coasts and forests leading to an intensive deposition of allochthonous substances in the local environment and consequent eutrophication, in turn altering the soil biogeochemistry, degrading the biodiversity and suppressing plants vegetation (Ishida, 1996;Anderson and Polis, 1999;Hobara et al, 2005;Kolb et al, 2012;Adamonytė et al, 2013).…”

Search for the Substantiation of Reasonable Native Elemental Background Values and Reference Variables in Topsoil on Glaciogenic and Postglacial Deposits in a Vilnius Peri-Urban Area

“…The used RMs and CRMs were prepared pari passu with our analyzed topsoil samples. Earlier, we mentioned these procedures in a series of publications including [3,[56][57][58][59][60][61].…”