Impact of Fraxinus excelsior dieback on biota of ash-associated lichen epiphytes at the landscape and community level

Abstract

The landscape-scale extinction of a tree species may have a negative impact on diversity of associated epiphytic species. We used ordination and hierarchical clustering methods to assess landscape and the community level effects of reduction in the abundance of European ash Fraxinus excelsior, caused by ash dieback, on the associated epiphytic lichen biota in Białowieża Forest (Poland)-the best preserved forest complex in Central Europe. At the landscape level ash decline impact on the biota of ash-associated epiphytic lichens was weak, due to the high diversity of tree species, which may serve as potential alternative hosts. At this level, oak and hornbeam are the most important alternative hosts, assuring the maintenance of ash-associated epiphytic lichens. Lime, alder, and hazel appeared to be less important but still may serve as substitute phorophytes to approximately 2/3 of the ash-associated lichen biota. About 90% of epiphytic biota are likely to survive on the landscape scale. However, at the community level of alder-ash floodplain forest, where ash was dominant, about 50% of ash-associated epiphytic lichen species are threatened by ash dieback. Our results highlight the importance of a spatial scale in conservation biology. Protection of large forest areas with rich diversity of phorophyte trees increases chances of survival of the associated epiphytic organisms.

Cumulative impact assessments of multiple host species loss from plant diseases show disproportionate reductions in associated biodiversity

“…However, the indirect effects via declines in species associated with the infected host plant are less widely acknowledged despite the growing body of evidence documenting such declines (Rabenold et al., 1998; Tingley et al., 2002; e.g. Cleavitt et al., 2008; Lõhmus & Runnel, 2014; Lubek et al., 2020). Our work is unique in that it considers the cumulative impact on biodiversity of plant pests/pathogens affecting sympatric plants, showing that the loss of two tree species is greater than sum of the associated species at risk from a decline in either host alone.…”

“…within a site or forest stand), then the impact of tree species loss will cascade far beyond obligate species, resulting in large declines in populations, and potentially extirpations, of other associated species. There is a growing body of evidence addressing the first point, indicating that a decline in one foundation tree species may impact on many hundreds of associated species (Ellis et al., 2012; Gandhi & Herms, 2010a, 2010b; Hultberg et al., 2020; Lõhmus & Runnel, 2014; Lubek et al., 2020; Mitchell et al., 2019a). However, the cumulative impact on biodiversity of plant pests/pathogens affecting sympatric tree species, and whether a lack of functional redundancy within the ecosystem will exacerbate these impacts (points two and three above) have not previously been studied.…”

Materiały do rozmieszczenia porostów i grzybów naporostowych Polski, 1

“…Catillaria croatica rośnie na korze drzew liściastych w lasach (Kukwa, Łubek, et al, 2012;Łubek et al, 2020). Gatunek ten został podany dopiero niedawno z terenu Polski i znany jest z Puszczy Białowieskiej (Kukwa, Łubek, et al, 2012;Łubek et al, 2020) Uwagi: plecha skorupiasta, szara; owocniki ciemnobrązowe do czarnych; parafizy główkowate na szczycie, z brązowym pigmentem; worki 8-zarodnikowe; zarodniki bezbarwne, dwukomórkowe (Smith et al, 2009). Catillaria nigroclavata jest epifitem (rzadziej bywa notowana na drewnie) podawanym z wielu regionów Polski, jednak rzadko (np.…”

Soil pH and Organic Matter Content Affects European Ash (Fraxinus excelsior L.) Crown Defoliation and Its Impact on Understory Vegetation

“…In such plots, we noted more species typical of fertile sites, but at the same time more species with high light and moisture requirements. It is possible that their high abundance might have resulted from increased light availability, caused by ash crown defoliation that led to a shift in the understory species composition [8], as well as the composition of epiphytic lichens [7]. This resulted in a reduced functional richness and dispersion of the species composition.…”

“…The disease causes ash loss or severe crown defoliation. Consequently, it can cause an ecological cascade effect in ash sites, resulting in the retreat of dependent organisms, e.g., invertebrates, epiphytic bryophytes, and lichens [7], as well as understory Table 1. Basic characteristics of the study plots.…”