Recovery of the Critically Endangered bracket fungus Amylocystis lapponica in the Estonian network of strictly protected forests K ADRI R UNNEL,INDREK S ELL and A SKO L ÕHMUS Abstract In regions where primeval forests have vanished it Targets (Convention on Biological Diversity, ) provide is unclear whether forest protection can sustain specialized political support to improve this situation by further ex- old-forest biota, and over what time scale. We report on panding reserve networks, restoring degraded ecosystems, population expansion of an old-growth specific fungus of and preventing species extinctions. However, the targets do European conservation concern, Amylocystis lapponica,in not specify how to combine conservation options in practice the forest reserve network of Estonia. This conspicuous (e.g. Jørgensen, ; Venter et al., ). species was known for years from only single records A central management problem in historically degraded, in one old-growth forest and was categorized nationally as but now protected forests is that old-growth qualities de- Critically Endangered. During the last years A. lapponica velop slowly, and the prospects for old-forest biota depend has expanded over the eastern half of the country, with nine on unpredictable colonization and extirpation processes. In subpopulations, in localities, now known, all in long- most countries protected forest networks have existed for protected old-growth forests and several . km apart. only a few decades and thus have limited structural recovery In most of the new localities historical absence of the (e.g. Meyer & Schmidt, ; Paillet et al., ; Bujoczek species can be reliably assessed based on earlier surveys. et al., ). There is some evidence of broad-scale recovery The historical remnant subpopulation has also increased. of species with moderate old-forest associations within The population size (c. mature individuals) in Estonia a few decades of the protection of secondary forests (e.g. indicates the species should be recategorized nationally as Vandekerkhove et al., ; Deinet et al., ; Romero Endangered. This success story suggests that more than et al., ), but such recoveries depend on species’ life his- years of non-intervention may be needed even in large tory traits,locationofsourcepopulations, and dispersal capa- old-forest reserves for old-growth specialist species to bilities (Sverdrup-Thygeson et al., ). Non-intervention recover. management has also enabled a disturbance-phase special- ist fungus to spread across large naturally disturbed areas Keywords Amylocystis lapponica, bracket fungus, forest, (Bässler & Müller, ). However, for the most demanding fungal conservation, old growth, Picea abies, refuge popula- old-forest species broad-scale recoveries attributable to tion, succession reserve network initiatives have not been described. Supplementary material for this article is available at Here, we report on population expansion of an old- https://doi.org/./S growth specific fungus Amylocystis lapponica (Agarico- mycetes, Polyporales, Polyporaceae) in the forest reserve network of Estonia. Although its preliminary global Red n many developed countries a major conservation List status is Least Concern (IUCN, ), in Europe it is Ichallenge is to sustain old-forest biota despite historical one of the threatened fungi recommended for listing in loss of natural forests. Most European countries retain , % the Bern Convention (Dahlberg & Croneborg, ). In of their primary forest (Sabatini et al., ) and reserves the last years this species has been recorded in eight already cover . % of current forest area (Forest Europe, European countries, with the majority of the population ). In degraded forests many old-forest specialist species in the boreal zone. Outside the boreal zone, this species is may not be viable and will be extirpated unless their habitat only present in a few refugia in the best-preserved Central is restored (Hanski, ). The global Aichi Biodiversity European primeval forests (Holec & Kučera, ). In Estonia (the hemiboreal zone) A. lapponica was known for years from a single old-growth patch (Parmasto, ), KADRI RUNNEL (Corresponding author, orcid.org/0000-0002-7308-3623) has been categorized as Critically Endangered since , Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise 46, EE-51014 Tartu, Estonia. E-mail [email protected] when first assessed (Lilleleht, ; Lõhmus et al., b), and is legally protected. INDREK SELL MTÜ Puuseen, Tartu, Estonia Forests currently cover % of Estonia’s , km land ASKO LÕHMUS Department of Zoology, Institute of Ecology and Earth Sciences, , University of Tartu, Tartu, Estonia area but old natural stands cover only %( km ), over half of which is in reserves (Raudsaar et al., ). Before sig- Received January . Revision requested February . Accepted April . First published online September . nificant spread of agriculture, c. BCE, forest cover was Oryx, 2020, 54(4), 478–482 © 2019 Fauna & Flora International doi:10.1017/S0030605319000334 Downloaded from https://www.cambridge.org/core. IP address: 170.106.35.234, on 27 Sep 2021 at 05:00:06, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605319000334 Critically endangered bracket fungus 479 probably at least %; spruce forests are a major ecosystem potential localities have been monitored by IS during of the east and south (Laasimer, ). At least % of land –. The fruit bodies of A. lapponica are easily detect- has remained long-term forest (although repeatedly logged), able when mature and fresh (Lõhmus, ), but parts and other forests are either th century reforestations (vari- of juvenile or old fruit bodies that could not be reliably ous types of agricultural lands) or new forests on drained identified have been collected for microscopy. Substrate wetlands. descriptions of the records were made on-site, but stand In the second half of the th century most Estonian characteristics are reported according to the National forests were managed with a medium-intensity semi-natural Forest Registry (based on geographical coordinates of the approach, which maintained tree species diversity and records). relatively high volumes of dead wood. As a consequence, The synthesis of these datasets reveals a recent expansion many generalist old-forest species could inhabit production of A. lapponica from a single forest reserve to other long- forests (e.g. Lõhmus et al., ; Runnel & Lõhmus, ). protected parts of the national network of protected forests. Nevertheless, several highly specialized species, including Its fruit bodies were first discovered in eastern Estonia in A. lapponica and other fungi of spruce-dominated forests, ,ina-ha old-growth patch, protected since remain highly threatened in protected old-forests or have (the first Estonian forest reserve) and surveyed by mycolo- already become regionally extinct (Runnel & Lõhmus, ; gists since the s. Despite frequent visits to this reserve, Lõhmus et al., b). the species was re-recorded on a single trunk only in , The Estonian network of strictly protected forests devel- , and . The findings became annual from oped slowly from until the s, without central plan- (three records), and with records in , the ning (Tuvi et al., ). Later focused developments include species had spread over most of the reserve. designation of Natura sites of European importance During – there were a total of additional re- and, nationally, targeting minimum areas for old-growth cords. The number of known subpopulations (here defined forest species in each forest type (Lõhmus et al., ). as localities separated by . km) expanded to nine (Fig. ); The area of strictly protected forests increased from c. % these include separate localities (contiguous forest areas of forest land in the early sto%in and %by with records typically , km and no more than km (Lõhmus et al., ; Raudsaar et al., ). However, apart). In two records were made in Muraka nature re- reflecting general forest history, few of the strictly protected serve (north-eastern Estonia), which is probably the largest sites include any primeval forest and . % of their total surviving primeval spruce forest in the country (officially area will still be , years old by (Lõhmus, ). protected since ; surveyed by mycologists since the Recently intensified timber harvesting has fragmented the s). In another locality . km away and another landscapes and isolated the strictly protected sites (Forest subpopulation km away were discovered. In , two Europe, ; Lõhmus, ). new subpopulations were found elsewhere in Estonia: in The A. lapponica material we analysed is based on fruit- Alam-Pedja Nature Reserve in east-central Estonia (de facto body records from three main sources, and survey histo- protected since when it became a Soviet military ries in these localities to evaluate historical absences area) and in old-growth stands in Karula National Park, (Supplementary Material ). () All casual collections of southern Estonia (officially protected since ). There Estonian polypores are documented in public database were a total of records in , all in long-protected for- Plutof (Abarenkov et al., ). Polypores have been well ests and most in previously surveyed areas (Supplementary surveyed since the s in Estonian forests, with emphasis Material ). These records included four additional subpo- on old forests and rare species. Parmasto () published pulations,