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Structural variables drive the distribution of the sensitive lichen Lobaria pulmonaria in Mediterranean old-growth forests
Abstract
We tested the hypothesis that structural variables related to old-growth features affect the distribution of Lobaria pulmonaria in a Mediterranean National Park of Italy. A total of 36 plots, with old-growth characteristics and representing overall three forest types (beech- oak- and mixed- forests) were studied. The lichen was absent in about half of the sites, suggesting that the selection of old-growth forests based solely on structural features is not sufficient to predict the presence of this species, which therefore proves to be rather sensitive and selective. Its abundance was related to high tree circumference and basal area, and to availability of deadwood, confirming the relevant effect of substrate and stand continuity in the conservation of this species and emphasizing its role of indicator species of undisturbed forest ecosystems with long ecological continuity.
... In biological conservation, L. pulmonaria has been confirmed as a good biodiversity indicator, since various studies give evidence of its role as a proxy for the biodiversity of other lichen species characterising the epiphytic alliance Lobarion pulmonariae Ochsn., which is considered a climax lichen community on mature hardwood trees in old forests across Europe [13]. Moreover, since the integrity of its populations guarantees the integrity of other species in the same habitat, it can also be considered an important umbrella species in forest sites [20][21][22][23][24]. ...
... A detailed list of these core articles is provided in Table 1. Biomonitoring radioactivity: 6 [77][78][79][80][81][82] Biomonitoring environmental and structural variables: 22 [23,25,43,[83][84][85][86][87][88][89][90][91][92][93][94][95][96][97][98][99][100][101] Feeding: 15 [102][103][104][105][106][107][108][109][110][111][112][113][114][115][116] Biomonitoring phytotoxic pollutants and acid rains: 4 [117][118][119][120] Biomonitoring historical or actual disturbances: 6 [121][122][123][124][125][126] ...
... Forest type influences the presence of L. pulmonaria as, for instance, in the Mediterranean area, Quercus forests are more suitable than a montane mixed forest, with Castanea forest in an intermediate position [95]. Within such forest types, L. pulmonaria is associated with old trees with large circumference and basal area [23,96]. Such preference could be the result of a combination of conditions on older and larger trees, together with higher cumulative probability of colonisation that results from a longer presence [23]. ...
Lobaria pulmonaria (L.) Hoffm. is a tripartite, broad-lobed foliose lichen usually found on bark and on epiphytic and epilithic mosses in humid forests. Currently, the species is threatened in most European countries because of its sensitivity to environmental alterations. In this paper, a total of 107 previous studies across more than 50 years were analysed to gain insight into the multiple roles that L. pulmonaria plays in forest habitats, specifically relating to ecosystem services and as environmental bioindicator. Content analysis was employed to systematically characterise and classify the existing papers on the functions performed by L. pulmonaria into several groups mostly based on research topic and scope. Two main types of ecosystem services (N2 fixation and feeding) offered by L. pulmonaria have been identified, with varying research aims and types of parameters measured in the studies. Two aspects of current biomonitoring applications using L. pulmonaria in forest habitats (concerning atmospheric pollution and forest management) were analysed, and it was found that the number of related studies increased significantly in recent years. Finally, the current practices of monitoring using L. pulmonaria as a biological indicator are discussed, and recommendations are provided.
... In particular, studying its abundance and the viability of its populations in forest plots may represent a suitable method for obtaining early-warning responses to environmental changes in the mediumto long-term periods. In this respect, many authors not only consider the occurrence and abundance of L. pulmonaria but also assess its conservation status and health in terms of active growth (presence of meristematic lobes) and dispersion capacity (presence of juvenile thalli, vegetative propagules, and fruiting bodies) (e.g., [80,81,83]). However, most of these studies investigate the effects of forest management and old-growth structural attributes. ...
... However, studies have shown that focusing on a single species can also have some drawbacks. Indeed, the distribution of single forest lichen species, as well as being affected by air pollution, may also be affected by microclimatic and/or biogeographic variables, thus reducing their effectiveness as bioindicators (e.g., [80,83]). ...
Currently, forest ecosystems are often located in remote areas, far from direct sources of air pollution. Nonetheless, they may be affected by different types of atmospheric deposition, which can compromise their health and inner balance. Epiphytic lichens respond to air pollution and climate change, and they have been widely adopted as ecological indicators, mainly in urban and industrial areas, while forest ecosystems are still underrepresented. However, in recent years, their use has become increasingly widespread, especially in the context of long-term monitoring programs for air pollution in forests. In this review, we provide a critical analysis of the topic from the point of view of the different methodological approaches based on lichen responses adopted in forest ecosystems. Further, we discuss the main challenges posed by the current global change scenario.
... Lobaria pulmonaria is also an indicator of important forest habitats for the conservation of understudied groups (e.g. bryophytes) (Scheidegger and Werth, 2009;Brunialti et al., 2015). Hence, its occurrence and abundance can be used for mapping forest sites worthy of conservation (Campbell and Fredeen, 2004;Nascimbene et al., 2010;Brunialti et al., 2015). ...
... bryophytes) (Scheidegger and Werth, 2009;Brunialti et al., 2015). Hence, its occurrence and abundance can be used for mapping forest sites worthy of conservation (Campbell and Fredeen, 2004;Nascimbene et al., 2010;Brunialti et al., 2015). ...
Species translocation can be considered as a primary conservation strategy with reference to in situ conservation. In the case of lichens, translocations often risk to fail due stress factors associated with unsuitable receptor sites. Considering the bioecological characteristics of lichens, air pollution is among the most limiting stress factors. In this study, the forest macrolichen Lobaria pulmonaria was used as a model to test the hypothesis that the translocation of sensitive lichens is effective only in unpolluted environments.
At purpose, 500 fragments or whole thalli were translocated in selected beech forests of Central Europe (the Western Carpathians, Slovakia) where the species disappeared in the past and in oak forests of Southern Europe (Tuscany, Central Italy) where native populations are present. Prior to the translocation (May 2016) and after one year, morphological and ultrastructural features, trace elements as well as chlorophyll a fluorescence emission were analysed. Four years later, the effectiveness of lichen translocation was further evaluated as presence of the transplants and of newly formed individuals.
After one year, the translocation ensured an effective survival of the thalli in remote oak and beech forests characterized by a negligible or low contamination by heavy metals. The transplants were considered successful and developed new lobules and rhizines, attaching by themselves to the bark of the host trees, looking overall healthy, without evident signs of alteration also at ultrastructural level. Moreover, in a few cases newly formed individuals were observed after four years. On the other hand, the results highlighted the link between the unsuccess of the translocation and air pollution in other areas of the Western Carpathians and suggested that current air quality still limits the possibility of recolonization in areas where the model species disappeared.
... size, age, health conditions) are the main drivers for these species, while at the stand level forest management is the main driver with contrasting effects. Intensive management is usually highly detrimental, while abandonment of management leading to closed canopy stands may also negatively affect this species (Nascimbene et al., 2013a(Nascimbene et al., , 2013b(Nascimbene et al., , 2016Brunialti et al., 2015). Besides local factors, also landscape features may influence the occurrence and abundance of this lichen, whose dispersal is mainly related to vegetative propagules over relatively short distances (Löbel et al., 2009). ...
... Due to its peculiar ecology and its easy detectability it is considered a valuable indicator of forest sites that host high lichen diversity and species of conservation concern (Nascimbene et al., 2010). Among these, species belonging to the order Caliciales are associated with old-growth stands characterized by long ecological continuity (Selva, 1994;Brunialti et al., 2015). ...
In mountain regions of southern Europe, old-growth chestnut orchards maintained by traditional management were a key component of the economic, cultural, and ecological heritage. Currently, many stands are abandoned due to decreased economic sustainability even though, according to European policies, the loss of traditionally managed old-growth chestnut orchards should be contrasted to prevent biodiversity loss. In this study, we preliminarily mapped the remnants of old-growth chestnut orchards across a region of the northern Apennines (Italy) with a strong tradition of chestnut orchard cultivation. Then, we assessed the effects of management/abandonment in terms of tree features (e.g. size, crown structure, health conditions), occurrence and abundance of target epiphytic lichens, and richness and composition of understory vegetation. Our results revealed contrasting patterns of tree features, lichen, and plant diversity in managed and abandoned old-growth chestnut orchards of the northern Apennines, supporting the view that traditional management is fundamental for the long-term maintenance of healthy veteran trees, the enhancement of epiphytic lichens related to old-growth conditions, and plant diversity. This indicates that 1000 years of chestnut civilization represent a cultural heritage that benefits nature conservation, promoting a virtuous interplay between human activities and biodiversity. For this reason, policies aimed at sustaining traditional management in old-growth chestnut orchards are indispensable to avoid the degradation and loss of this habitat and its centuries-old cultural and ecological legacy.
... Undoubtedly, L. pulmonaria fits these indicator species criteria but does not fully adhere to the first and the last two criteria based on the observations reported here. Indeed, the species can persist and reproduce in a landscape moderately disturbed by human activity (Scheidegger and Werth, 2009;Jüriado and Liira, 2010;Brunialti et al., 2015). These finding indicate the need for further research and a possible revision of the view on the ecological requirements and methods of species protection in Poland. ...
North−eastern Poland is an area of high natural values, including a well−preserved, varied and rich biota of lichens. It is a kind of refuge for many lichen species. Lichens are much more frequent and more abundant here than in other regions of the country. The Białowieża Forest is distinguished by the presence of the best−preserved natural habitats in the Polish lowlands. The lichen biota of the Białowieża Forest has been studied by many lichenologists. The data were provided by numerous studies dating back to the 19th century. Lichens belong are of significant importance for the natural environment; moreover, they are most sensitive to contemporary anthropogenic changes in natural environments. Many species occurring in Poland are threatened with extinction. One of the flagship lichen species in Poland is the lungwort lichen Lobaria pulmonaria (L.) Hoffm. It is a characteristic representative of the lichen biota of the whole country and an icon for protection of these organisms. The thalli are easily visible and their identification is unquestionable. The lungwort lichen is one of the most impressive lichens in Poland. It is mainly found in old, undisturbed forests where it is often accompanied by other rare lichen species with similar ecological requirements. The lungwort lichen is an umbrella species, protecting other valuable and rare species. It grows mainly on the bark of deciduous trees, but it has been recorded on exception from the bark of conifers (spruce, fir, pine). A new location of L. pulmonaria was found on Malus domestica Borkh. in 2021. The home apple tree bearing the lungwort lichen is located in the Podcerkwa nature reserve in Polana Berezowo. The tree grows in an open space, a former hunting ground, now a mid−forest meadow mowed as part of a nature reserve protection plan or species protection program. The lichen thallus is located on the north−eastern side of the tree (N−E). The largest thallus is about 17 cm wide, at a height of about 2 m. The tree also has a few smaller thalli, 2 to 10 cm in size, located up to a height of about 3.5 m. Thanks to the discovery of a new site in the Białowieża Forest District, the home apple tree M. domestica Borkh. should also be added to the phorophytes of the lungwort lichen. Until now, in the Polish literature, the lichen has not been recorded from this tree species.
... It is a tripartite foliose epiphytic species with a thallus often exceeding 20-30 cm in diameter, and has green algae as its main photobiont and nitrogen-fixing cyanobacteria within its cephalodia. It is considered a flag species for lichen conservation and also an umbrella species-a suitable sensitive indicator of forest habitats worthy of conservation and hosting other rare lichens (e.g., cyanolichens) [5,7,12,13]. The species has declined throughout Europe as a consequence of air pollution (especially past air pollution) and is threatened by intensive forest management, the effects of which are expected to be further exacerbated by climate change [14]. ...
Microclimatic conditions are important in determining lichen distribution at small scale, and may determine whether the species persist when the surrounding environmental conditions have drastically changed. This is the case with forest management, since a sudden variation of microclimatic conditions (increase of solar radiation, temperature, wind and a reduction of humidity) may occur after logging. In this study, the combined effect of forest logging and microclimatic conditions on the growth probabilities and growth rates of the model species Lobaria pulmonaria was assessed in mixed oak stands. To this purpose, 800 fragments of L. pulmonaria (<1 cm) were transplanted in logged and unlogged stands for two years. Young and adult fragments were positioned on Turkey oak boles according to distance from the ground (100 and 50 cm) and aspect (north and south). The results, evaluated by generalized linear mixed models on a yearly basis, highlighted differences in growth—particularly on isolated trees in the logged stand. South-exposed samples in the logged stand showed a low probability of growth, while samples transplanted north in the unlogged stand showed higher growth probabilities. However, the highest annual growth coefficients corresponded to south-exposed samples 50 cm from the ground in the unlogged stand. In general, higher growth rates were observed in young thallus fragments when compared with adult ones. Beyond confirming the importance of microclimate for lichen ecology, these results could be implemented in conservation actions to preserve L. pulmonaria populations in logged forests.
... According to Mittermeier et al. (2005), states such as Paraná and Rio Grande do Sul were pioneers in the creation of Conservation Units in the Atlantic Forest already in the 1950's, which explains the comparatively high tree cover values notable species richness. The numerous Lobarioideae characteristic of these two metacommunities is in line with studies that found Lobarioideae species good indicators of forest health (Hodkinson et al. 2014;Giorgio et al. 2015;Ramírez Morán et al. 2016;Ranft et al. 2018). The greater number of lichen studies in this area is not necessarily a factor, as sampling bias was largely mitigated by background manipulation via the bias file in the modeling approach. ...
... The vegetative dispersal distance of L. pulmonaria is only 15-30 m (Jüriado et al., 2011). According to numerous reports, L. pulmonaria most often colonizes the trunks of large deciduous trees with a rough bark (Gu et al., 2001;Jüriado et al., 2011Jüriado et al., , 2012Brunialti et al., 2015), which might be considered as a limiting factor in the distribution of this species. ...
The population structure of the lichen Lobaria pulmonaria (L.) Hoffm. was analyzed in the Vodlozersky National
Park (Karelia, Russia), for middle boreal forest stands having a time-since-disturbance spanning 80 to 450 years. To estimate the
age of the last disturbance, a method of evaluation for the tree population structure was applied. The forest stand communities
belonged to a successional series: middle-aged aspen – mixed aspen-spruce – pre-climax spruce – climax (old-growth) spruce
forest. All thalli (1055) of L. pulmonaria from all substrate units (165, separately standing or lying trees and shrubs) were
described within 7 sample plots of 1 ha. For each thallus, the area (cm2
) and the functional-age group were determined. The
number of Lobaria thalli per ha, number of substrate units, number of substrate types (living, standing dead and lying dead
trees of different species) colonized by L. pulmonaria, as well as number of substrate types on which the lichen had completed
its life cycle increased with time-since-disturbance.
... Th e lichens Lobaria pulmonaria dominate, smothering brunches of fi rs (Budaeva, 2014). Th e habitats of Lobaria pulmonaria are limited by air pollution; this specie is quite rare in Europe (Giorgio, Luisa, & Sonia, 2015;Riga-Karandinos & Karandinos, 1998;Nadyeina, Dymytrova, Naumovych, Postoyalkin, & Scheidegger, 2014). It is known that over the territory of Western Siberia and the Urals, Lobaria pulmonaria grows in the areas with minimal extent or absence of anthropogenic impact. ...
The research is devoted to the investigation of chemical composition of epiphytic lichens Lobaria pulmonaria growing in the territory of the Barguzin Nature Reserve in the Republic of Buryatia (Russia). This reserve is considered as a background area because of its far location from anthropogenic pollution sources. The objective of this research is to assess the chemical composition of lichens of the Barguzin Nature Reserve – one of the background areas in Russia. 9 lichen samples were collected in the summer 2015, in which the concentrations of 67 chemical elements were detected using inductively coupled plasma mass-spectrometry. The research findings were compared with the data for the lichens from the Zabaykalsky National Park and taiga forest in Tomsk region (oil field area). Comparing the reserve area with the taiga area (with anthropogenic load from oil field development), it was detected that the lichens from the Barguzin Nature Reserve had lower concentrations of most chemical elements except Na, Mg, Al, Si, P, K, Ca, and Ti, which contents are 2-16-fold higher in the lichens of the Barguzin Reserve. The concentrations of most chemical elements detected in the lichen samples of the Barguzin Nature Reserve can be used as baseline values while investigating territories with different anthropogenic load.
Although epiphytic lichens are widely adopted as environmental indicators, they are not yet included among the target species listed in Annex II of the Habitats Directive, to which the system of protected areas of the Natura 2000 network refers. In this work, we aim to test the effectiveness of this system, mainly designed for the conservation of other groups of species, in protecting lichen species richness. For this purpose, we considered a case study (Central Italy) with half of the territory included in protected areas. Statistical differences in species richness and lichen communities were tested between sites located in 16 Protected Areas (PA) and 11 Non-Protected Areas (NPA) using non-parametric tests, multi-response permutation procedures (MRPP), non-metric multidimensional scaling (NMDS) and Indicator Species Analysis (ISA). Despite the broad overlap between epiphytic lichen communities of NPAs and PAs and a similar number of total and common species, PAs contain a significantly higher number of nationally rare and extremely rare species, including cyanolichens. These results are also confirmed by the indicator analysis. Although the Natura 2000 network does not explicitly address the conservation of lichens, the protected areas in our study can play a role in protecting the diversity of epiphytic lichens, especially nationally rare and endangered species. However, the future inclusion of red-listed epiphytic lichens among the target species of Annex II of the Habitats Directive would be welcome to better protect these organisms on a European level.
With the publication of a Decree that has established a List of the Italian old-growth forests, we have analyzed, using text mining software, the state of the art of Italian research in this field. We have analyzed 188 ISI and 72 non-indexed papers or reports. The analysis has identified 165 locations of which more than 50% are on pure beech or mixed beech and silver fir stands. The analysis was focused mainly on structural characteristics and bio-indicators. The current knowledge represents reliable support for the establishment of an Italian network of old-growth forests and this green infrastructure offers important opportunities for research and collaboration between research, natural resource management, and local, regional, and state administrations.
Sustainable Forest Management (SFM) indicators consider the main ecological and socioeconomic functions of forests but do not currently include some key groups widely adopted to assess the effects of forest management, such as herbaceous vascular plants, epiphytic lichens, and wood-decay fungi. Moreover, they are shaped into high forests while in the Mediterranean area the oldest type of forest management is coppice. We investigated the diversity and the relationships of the above-mentioned groups of taxa in three European Forest Types (EFTs) to contribute to the selection of indicator species suitable for monitoring Mediterranean coppice forests. We find only a weak cross-taxon congruence between vascular plants and lichens on considering the whole dataset, while no significant correlations are evident within the three EFTs. Species richness was significantly different among EFTs, being Thermophilous deciduous forests the richest, both considering the groups of taxa separately and the total species richness. As for species composition, significant differences were found both for the whole dataset and also for pairwise comparisons among EFTs. We provided a dwelling-species list of the three key groups of taxa, which could be suitable for monitoring the sustainability characteristics of fragmented and low continuity forests such as coppice stands.
• Highlights
• Vascular plants, epiphytic lichens and wood-decay fungi relationship in coppice stands
• Weak cross-taxon congruence between vascular plants and lichens
• Significant differences in species richness and composition among forest types
• We provide a list of dwelling-species suitable for monitoring coppices
Forest logging can be detrimental for non-vascular epiphytes, determining the loss of key
components for ecosystem functioning. Legal logging in a Mediterranean mixed oak forest (Tuscany,
Central Italy) in 2016 heavily impacted sensitive non-vascular epiphytes, including a large population
of the threatened forest lichen Lobaria pulmonaria (L.) Hoffm. This event offered the background for this
experiment, where the potential effects of logging in oak forests are simulated by means of L. pulmonaria
micro-transplants (thallus fragments <1 cm). Our working hypothesis is that forest logging could
negatively influence the growth of the thalli exposed in logged stands compared to those exposed in
unlogged stands. One hundred meristematic lobes and 100 non-meristematic fragments are exposed
for one year on 20 Turkey oak trees (Quercus cerris), half in a logged and half in an unlogged stand.
Chlorophyll (Chl) a fluorescence emission and total chlorophyll content are used as a proxy for the
overall vitality of the transplants, while their growth is considered an indicator of long-term effects.
Generally, vitality and growth of the transplants in the logged stand are lower than in the unlogged
stand. Both vitality and growth varies between the meristematic and non-meristematic fragments,
the former performing much better. Hence, irrespective of forest management, meristematic fragments
show higher growth rates (0.16–0.18 cm2 year-1) than non-meristematic ones (0.02–0.06 cm2 year-1).
Considering that a conservation-oriented management for this species should be tailored at the
habitat-level and, especially, at the tree-level, our results suggest that for appropriate conservation
strategies, it is necessary to consider the life cycle of the lichen, since the probability of survival of the
species may vary, with meristematic fragments having more chance to survive after logging.
We present a phylogenetic revision of the Sticta filix morphodeme in New Zealand. This non-monophyletic group of early diverging clades in the genus Sticta is characterized by a stalked thallus with a green primary photobiont and the frequent formation of a dendriscocauloid cyanomorph. Traditionally, three species have been distinguished in New Zealand: S. filix (Sw.) Nyl., S. lacera (Hook. f. & Taylor) Müll. Arg. and S. latifrons A. Rich., with two cyanomorphs separated under the names Dendriscocaulon dendriothamnodes Dughi ex D. J. Galloway (traditionally associated with S. latifrons ) and D. dendroides (Nyl.) R. Sant. ex H. Magn. (traditionally associated with S. filix ). Sticta lacera was not included in the present study due to the lack of authentic material (all specimens originally identified under that name and sequenced clustered with S. filix ); S. filix was confirmed as a distinct species whereas S. latifrons s. lat. was shown to represent two unrelated species, S. latifrons s. str. and the reinstated S. menziesii Hook. f. & Taylor. The cyanomorphs of S. filix and S. latifrons are not conspecific with the types of the names D. dendriothamnodes and D. dendroides , respectively; the D. dendriothamnodes cyanomorph belongs to the Australian taxon Sticta stipitata C. Knight ex F. Wilson, which is not present in New Zealand, whereas the D. dendroides cyanomorph corresponds to a previously unrecognized species with unknown chloromorph, recombined here as Sticta dendroides (Nyl.) Moncada, Lücking & de Lange. Thus, instead of three species ( S. filix , S. lacera , S. latifrons ) with their corresponding cyanomorphs, five species are now distinguished in this guild in New Zealand: S. dendroides (cyanomorph only), S. filix (chloro- and cyanomorph), S. lacera (chloromorph only), S. latifrons (chloro- and cyanomorph) and S. menziesii (chloro- and cyanomorph). A key is presented for identification of the chloromorphs and the dendriscocauloid cyanomorphs of all species. Semi-quantitative analysis suggests that species in this guild are good indicators of intact forest ecosystems in New Zealand and that the two newly recognized species, S. dendroides and S. menziesii , appear to perform particularly well in this respect. The use of lichens as bioindicators of environmental health is not yet established in New Zealand and so, based on our results, we make the case to develop this approach more thoroughly.
The conservation of biological diversity is recognized as a fundamental component of sustainable development, and forests contribute greatly to its preservation. Structural complexity increases the potential biological diversity of a forest by creating multiple niches that can host a wide variety of species. To facilitate greater understanding of the contributions of forest structure to forest biological diversity, we modeled relationships between 14 forest structure variables and airbdrne laser scanning (ALS) data for two Italian study areas representing two common Mediterranean forests, conifer plantations and coppice oaks subjected to irregular intervals of unplanned and non-standard silvicultural interventions. The objectives were twofold: (i) to compare model prediction accuracies when using two types of ALS metrics, echo-based metrics and canopy height model (CHM)-based metrics, and (ii) to construct inferences in the form of confidence intervals for large area structural complexity parameters. Our results showed that the effects of the two study areas on accuracies were greater than the effects of the two types of ALS metrics. In particular, accuracies were less for the more complex study area in terms of species composition and forest structure. However, accuracies achieved using thb echo -based metrics were only slightly greater than when using the CHM-based metrics, thus demonstrating that both options yield reliable and comparable resultS. Accuracies were greatest for dominant height (Hd) (R-2= 0.91; RMSE%= 8.2%) and mean height weighted by basal area (R-2 = 0.83; RMSE%= 10.5%) when using the echo -based metrics, 99th percentile of the echo height distribution And interquantile distance. For the forested area, the generalized regression (GREG) estimate of mean Hd Was similar to the simple random sampling (SRS) estimate, 15.5 m for GREG and 16.2 m SRS. Further, the GREG estimator With standard error of 0.10 m was considerable more precise than the SRS estimator With standard error of 0.69 m.
The conservation of biological diversity is recognized as a fundamental component of sustainable development, and forests contribute greatly to its preservation. Structural complexity increases the potential biological diversity of a forest by creating multiple niches that can host a wide variety of species. To facilitate greater understanding of the contributions of forest structure to forest biological diversity, we modeled relationships between 14 forest structure variables and airborne laser scanning (ALS) data for two Italian study areas representing two common Mediterranean forests, conifer plantations and coppice oaks subjected to irregular intervals of unplanned and non-standard silvicultural interventions. The objectives were twofold: (i) to compare model prediction accuracies when using two types of ALS metrics, echo-based metrics and canopy height model (CHM)-based metrics, and (ii) to construct inferences in the form of confidence intervals for large area structural complexity parameters.
Scientists and land managers have been concerned about the state of forest lichens for many years. Most of the studies published during the last 100 years on lichens and pollution (e.g. reviews [49, 65] and section 1, this volume) have involved lichens on trees, and many studies have investigated forest lichen communities. In the last 50 years, concern about the loss of lichen diversity in connection with forest management and forest fragmentation has led to many studies designed to assess patterns and monitor trends of lichen biodiversity in forests worldwide (e.g. reviews [2, 82]). Recognition of the regional, continent-wide, and even global scale of adverse impacts on lichen communities has fostered studies and monitoring efforts designed to assess the impact of multiple factors adversely affecting forest lichen communities at large scales [43].
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Although selection cutting is probably less harmful to forest ecosystems than clear cutting, its effects on biodiversity remain largely unexplored. We investigated the previously unstudied effects of selection cutting on the abundance and fertility of two dominating species of epiphytic lichens, Lobaria pulmonaria and Lobaria quercizans , in a northern hardwood forest of New Brunswick, Canada.
Twenty‐eight forest stands were selected representing two contrasting silvicultural treatments: fairly recent selection cuts (5–9 years) and ‘uncut’ stands that had been subjected to low‐intensity single‐tree cutting at least 35 years ago. Within each stand, we quantified the abundance and fertility of lichens on 36 trees together with selected forest stand variables.
Although both species had survived harvesting, the abundance of L. quercizans and L. pulmonaria was four and five times higher, respectively, in uncut stands than in selection cuts. The most important predictive factors for lichen abundance at the stand level were total basal area and canopy closure, which were much lower in selection cuts. Furthermore, the abundance of both species at the tree level was significantly correlated with tree size.
Most interestingly, fertile L. quercizans and L. pulmonaria were, respectively, five and 26 times more frequent in uncut stands. In addition, for L. pulmonaria the fertility frequency was only 3% in selection cuts, compared with 37% in uncut stands. The fertility of both lichen species was strongly correlated with their abundance at the tree level.
Synthesis and applications. Our results indicate that selection cutting has a strong impact on the abundance and fertility of these two Lobaria species, and that studies ignoring fertility may underestimate the negative effects of forestry on lichens. To reduce the negative effects we have three recommendations. (i) Large trees from old seral stages should be retained during selection cuts. (ii) The cutting cycle should be extended and the basal area removed should be reduced. These actions would improve the microclimate, increase the amount of suitable habitat and prolong the time window for lichen colonization in selection cuts. (iii) Some mature deciduous forest stands should be protected at the regional scale. This would promote the long‐term persistence of large, sexually reproductive lichen populations and concurrently benefit all species tightly linked with mature hardwood forests.
This study is focused on the selection of variables affecting lichen and bryophyte diversity in Mediterranean deciduous forests. Plots representing two forest types (Fagus sylvatica and Quercus cerrisforests) and two forest continuity categories (old-growth (OG) and non-OG forests) were selected in the Cilento and Vallo di Diano National Park (Italy). The presence and the abundance of bryophytes and epiphytic lichens were recorded. Structural variables of the forests and vascular plant species richness have been used as predictors. A strong positive correspondence between the two groups of organisms was found. Higher species richness and the distribution of rare species are related to OG stands, while a qualitative (species composition) rather than a quantitative (species richness) difference between the two forest types was observed. Some species elsewhere considered as indicators of forest continuity, such as Lobaria pulmonaria, Antitrichia curtipendula, and Homalothecium sericeum, are associated with OG forests, independently from forest type, suggesting that they can be regarded as suitable indicators also in Mediterranean forests. Finally, our results suggest that old trees, high levels of basal area, a broad range of diameter classes, and high understory diversity are the main structural features affecting cryptogamic communities, while no correlation was found with the occurrence of deadwood.
Forest inventories are evolving towards multipurpose resource surveys, broadening their scope by including additional topics such as biodiversity issues. Surprisingly, few quantitative surveys have been devoted to old-growth forests, even if they constitute the most acknowledged forest biodiversity icons. In this framework, the use of probabilistic sampling may provide an effective as well as rigorous support for monitoring and assessing old-growth forests. To this purpose, the present paper proposes a two-phase sampling scheme. In the first phase, a coarse survey of few floristic and stand structural attributes is carried out by means of small plots systematically placed on the study area. Subsequently, in the second phase, a fine assessment of a large number of ecological attributes is performed on a subset of enlarged plots selected among the first-phase ones by means of simple random sampling without replacement. The proposed sampling scheme is implemented for monitoring and assessing the old forests of Cilento National Park (southern Italy). Results and comments are provided as an exemplicative case study.
Many epiphytes in Swedish beech forests are associated with old and damaged trees. In this study we examined the impact of bark, soil and stemflow pH, water-holding capacity and bark structures on this association. We also analyzed whether the influence of these factors differed between species of conservation concern (red-listed and indicator species of woodland key habitats) and species not of conservation concern. One hundred and one age-determined living beech trees (range 58–277 yrs) in 13 beech-dominated stands were surveyed in a forest landscape in southern Sweden. We recorded 119 species in total (76 lichens, 43 bryophytes) of which 21 were red-listed and 17 indicator species (26 lichens, 12 bryophytes). NMS ordination showed that the species composition of lichens changed primarily with tree age and along the gradient of smooth bark versus moss cover. Bark pH and tree vitality were the most important gradients for bryophyte composition. The combination of old damaged beech trees and high bark pH resulted in the highest mean number of species of conservation concern for both lichens and bryophytes. The link between these factors is partly explained by a positive effect of tree age on the stemflow pH. Species number of bryophytes not of conservation concern increased with bark pH, whereas the corresponding group of lichens was favored primarily by increased light availability. Neither the water-holding capacity of bark nor soil pH affected patterns of species number. The results from this study show that old beech trees infected by fungi, with a higher bark pH, are the most valuable trees for epiphytes of conservation concern.
Lobaria pulmonaria and other members of the Lobarion were found to inhabit drainage channels below old and large wounds on the trunks of various deciduous trees in stands of long ecological continuity in a forest reserve dominated by Picea abies in southeastern Norway. Such channels were richer in minerals and had a higher pH than normal bark, which was covered with more acidophytic epiphytic communities, mainly the Pseudevernion. Chemical microhabitat differentiation was most clear in edaphically poor sites. The restriction of a previously ubiquitous Lobarion to mineral-rich microsites on stems is probably an effect of acid rain. Since acidification seems to make the Lobarion more dependent upon old and damaged stems, modern forestry probably aggravates the damage caused by acid rain.
119 investigated Quercus trunks and 67 species of lichens, 23 bryophytes and 3 non-lichenized fungi are arranged by means of the Minimum Spanning Tree analysis, resulting in four Lobarion communities and one Parmelion community. Lobarion is restricted to bark with pH > 5.0 in old forests. pH and Ca-content in the bark are strongly correlated; Ca seems to originate from Ca-uptake through the roots of the phorophyte. Within a single site the soil also seems to be responsible for the variation in the Mg-content of the bark, being correlated with Ca. The dominating source of the regionalvariationinMg, however, seems to be marine aerosols. Parmelion caperatae occurs on acid bark of young trees. The bark is, however, rich in Mg. Soluble tannins in the bark decrease with increasing age of the phorophyte, but are probably of minor significance for the epiphytic vegetation.
Vegetative diaspores of Lobaria pulmonaria were transplanted to previously uncolonized trees. The early development of the corticated but otherwise non-stratified isidioid soredia was studied mainly by low-temperature scanning electron microscopy. Anchoring hyphae developed from cortical hyphae after 2–4 months and later apical or lateral pseudomeristematic growth zones were formed. After 15 months the growth zones further differentiated into 0·5-mm-broad lobes and revealed a stratified thallus typical for this foliose epiphytic lichen species. The experiment showed that the small population size of L. pulmonaria was limited by the low reproductive potential of the species and that it might fail to compensate for a relatively high disturbance, natural or anthropogenic, in the stand.
The effects of two logging strategies and edge effects on cover and abundance of the epiphytic chlorolichens Cavernularia hultenii , Platismatia glauca and P. norvegica were studied in an experimentally logged boreal spruce forest. Whether lichen size distribution within the three species was affected by logging regimes was also tested. One hundred and ten branches were sampled at random within: (1) fine-grained clearcuts consisting of 23 cutblocks 0·25 ha each; (2) coarse-grained clearcuts consisting of 3 clearcuts 2·25 ha each; and (3) a control area.
Of the three species studied, C. hultenii was the most vulnerable to logging, with an abundance much lower in logged areas than in the control area. By contrast, P. glauca was equally abundant in the fine-grained area and in the control area, but significantly less abundant in the coarse-grained area where it seems to have been adversely affected by a pronounced edge effect. No such edge effect, however, was noted in the fine-grained area. Juvenile thalli of C. hultenii and P. glauca were less frequent in the coarse-grained area than in the fine-grained and control areas, suggesting that the juvenile stage might be more sensitive to logging than mature thalli. These results indicate that creation of large clearcuts (2·25 ha) may not be in accordance with the goal of maintaining population size in either C. hultenii or P. glauca . However, P. glauca does not seem to be negatively influenced by a fine-grained logging pattern. No effect of logging strategy or distance from the forest edge was observed on P. norvegica . It follows from the above that any management plans aimed at maintaining population size should be based on an understanding of ecology and life history gleaned from the area in question.
We tested whether the conspicuous lichen Lobaria pulmonaria indicates the number of tree‐dependent, red‐listed species in a hemiboreal forest in southern Sweden. In 18 naturally regenerated, mainly old deciduous forest plots considered to be of high or very high conservation value, the number of red‐listed tree lichens or wood beetles was not positively correlated with the area of the forest stands studied (8–56 ha). The 8 stands with L. pulmonaria had about nine (median) red‐listed lichens, but 10 stands without L. pulmonaria had only about one such species, a highly significant difference. Similarly, the variation between stands in the number of red‐listed wood beetles was considerable, but it was very weakly correlated with the number of red‐listed lichens. The number of red‐listed wood beetles dependent on dead trees was not different in areas with or without Lobaria pulmonaria, but the number of red‐listed wood beetles dependent on hollow trees was higher in stands with Lobaria pulmonaria (median of seven species) than in those without (three species) the lichen. Stands with this lichen species also contained significantly more of other types of lichens that have been proposed as indicators of forest continuity according to three lists. We stress the need for identification of species that could serve as indicators of different types of forest continuity and identify some organism groups that may indicate the different types .
Los líquenes y coleópteros dependientes de árboles como indicadores en los bosques bajo conservación
Lichen-forming fungi are mutualistic symbiotic organisms. The mycobiont coexists with one or more algal or cyanobacterial photobionts. Conservation biology of lichens deals, therefore, with more than one organism, although it is the fungal partner, or mycobiont, which is generally the target for conservation. It is also the mycobiont which determines the systematic position of lichens.
Fragmentation represents a serious threat to biodiversity worldwide, however its effects on epiphytic organisms is still poorly understood. We study the effect of habitat fragmentation on the genetic population structure and diversity of the red-listed epiphytic lichen, Lobaria pulmonaria, in a Mediterranean forest landscape. We tested the relative importance of forest patch quality, matrix surrounding fragments and connectivity on the genetic variation within populations and the differentiation among them. A total of 855 thalli were sampled in 44 plots (400 m(2)) of 31 suitable forest fragments (beeches and oaks), in the Sierra de Aylln in central Spain. Variables related to landscape attributes of the remnant forest patches such as size and connectivity and also the nature of the matrix or tree species had no significant effects on the genetic diversity of L. pulmonaria. Values of genetic diversity (Nei's) were only affected by habitat quality estimated as the age patches. Most of the variation (76%) in all populations was observed at the smallest sampled unit (plots). Using multiple regression analysis, we found that habitat quality is more important in explaining the genetic structure of the L. pulmonaria populations than spatial distance. The relatively high level of genetic diversity of the species in old forest patches regardless of patch size indicates that habitat quality in a highly structured forest stand determines the population size and distribution pattern of this species and its associated lichen community. Thus, conservation programmes of Mediterranean mountain forests have to prioritize area and habitat quality of old forest patches.
Orographic precipitation over interior mountains has resulted in the formation of the inland temperate rainforest, where certain stands are potentially antique and support a rich flora of epiphytic macrolichens. We documented macrolichen diversity across three age-classes in forests of the Interior Cedar-Hemlock biogeoclimatic zone (i.e., ICHwk3 subzone) east of Prince George, British Columbia. Our objectives were to report changes in lichen communities with stand age, identify potential indicators of antiquity, and investigate the functional role of dominant species in the ecosystem. We identified 41 taxa, including 4 alectorioid lichens, 21 foliose chlorolichens, and 16 old-growth-associated chlorolichens and cyanolichens. Older forests supported more species than young or mature forests. The abundance of Lobaria pulmonaria (L.) Hoffm. was strongly correlated with this increase in diversity and may therefore be an appropriate indicator of stand age in the ICH. The increase in L. pulmonaria and other N2-fixing cyanolichens with stand age may have significant implications for forest nitrogen budgets in the interior of British Columbia, where atmospheric nitrogen deposition is relatively low and biological N2 fixation accounts for nearly all of the nitrogen lost to forest harvesting. We hope that this greater understanding of lichen ecology across age-classes will promote sustainable stewardship of the remaining old-growth forests of inland British Columbia.
Liira, J. & Sepp, T. 2009: Indicators of structural and habitat natural quality in boreo-nemoral for-ests along the management gradient. — Ann. Bot. Fennici 46: 308–325. We aimed to quantify the effects of anthropogenic disturbances on forest structure and diversity in deciduous and mixed boreo-nemoral stands, conditioned on potential con-founding factors. Based on these results, we created a statistically-supported indicator list of stand "naturalness". We surveyed 50 quantitative and qualitative characteristics of a stand, the understorey and forest fl oor, and several widely accepted biodiversity indicators in 171 forests in Estonia. Multi-factorial GLM and GLIM analyses showed that many forest structural characteristics were confounded by forest site-type specifi -city, stand age and/or biogeography. Near-natural old-growth forests had higher propor-tions of deciduous trees, a larger amount of coarse woody debris, a higher frequency of logs in each decay class, a denser understorey, and were more homogeneous in the horizontal pattern of each layer than mature managed forests. By improving light condi-tions, forest management indirectly increased herb layer richness and coverage and the proportion of graminoids. The critical easy-to-apply set of indicators to assess forest ecosystem quality includes the amount and type of dead wood, the canopy closure of a stand and the presence of specially-shaped trees, specifi c epiphytic indicator lichens, mosses and wood-dwelling insects, and forest site-type specifi c herb layer species.
Conservation biologists have used surrogate species as a shortcut to monitor or solve conservation problems. Indicator species have been used to assess the magnitude of anthropogenic disturbance, to monitor population trends in other species, and to locate areas of high regional biodiversity. Umbrella species have been used to delineate the type of habitat or size of area for protection, and flagship species have been employed to attract public attention. Unfortunately, there has been considerable confusion over these terms, and several have been applied loosely and interchangeably. We attempt to provide some clarification and guidelines for the application of these different terms. For each type of surrogate, we briefly describe the way it has been used in conservation biology and then examine the criteria that managers and researchers use in selecting appropriate surrogate species. By juxtaposing these concepts, it becomes clear that both the goals and selection criteria of different surrogate classes differ substantially, indicating that they should not be conflated. This can be facilitated by first outlining the goals of a conservation study, explicitly stating the criteria involved in selecting a surrogate species, identifying a species according to these criteria, and then performing a pilot study to check whether the choice of species was appropriate before addressing the conservation problem itself. Surrogate species need to be used with greater care if they are to remain useful in conservation biology.
Very old, undisturbed forest stands may be important for biodiversity through their content of microhabitats or for the long periods available for colonisation, or for both. The term Ecological Continuity (EC) has been used to ascribe value to old forest stands. The relative importance of microhabitat and time for colonisation are usually not kept apart when EC is used as a conservation criterium. EC is broadly applied but poorly defined. Use of EC may lead to underestimation of the importance of forest dynamics and dispersal, and to overestimation of the importance of local land use history. If bioindicators of long-term habitat persistence are to be used, species with low dispersal capacity should be chosen. However, many lichens and other fungi, bryophytes and insects cited as indicators of EC, seem to have a patch-tracking lifestyle. They are 'colonists' according to life history strategy classification, and rather seem to indicate specific microhabitats. Terrestrial molluscs, some vascular forest plants, and those bryophytes and lichenized fungi classified as 'perennial stayers' in life history strategy classification, might be used to indicate long-term habitat persistence in forests, but more research is needed to evaluate such indicators.
We tested the hypothesis that changed microclimate at induced forest edges causes reduced growth of epiphytic lichens. Two
foliose, green algal lichens were transplanted to the lower canopy of a mature Picea abies forest at six distances (2, 6.25, 12.5, 25, 50 and 100 m) from a clearcut. The biomass growth in Platismatia glauca (6.2% in 16 months) was 41% higher than in Lobaria pulmonaria (4.4%). We found no growth reduction near the forest edge. In contrast, the highest growth in both species occurred within
12 m from the edge. Further, fluorescence and chlorophyll measurements showed that lichen vitality was unaffected by distance
from edge. The light intensity was 4.3 times higher at the edge than in the interior during the growing season, but there
were only minor differences in air temperature and relative humidity. Monitoring of thallus water content revealed clear differences
in both number and length of wetting and drying cycles. However, the total time with water content sufficient for photosynthetic
activity was only slightly higher at the edge. The data thus indicate that our gradient in microclimate was too small to significantly
affect lichen growth, and that lichens are largely metabolically inactive when large edge-interior contrasts in microclimate
occur. Lichen response to forest edge microclimate results from intricate interactions among several biotic and abiotic factors.
Linking data on lichen growth, microclimate and thallus water content with physiological measurements provides a framework
for future studies of the mechanisms behind abiotic edge effects.
The "New Forestry" practice of green-tree retention is becoming an important management tool for publicly owned lands, yet few data exist to demonstrate that this tool can succeed at enhancing biodiversity. We addressed this issue by using a retrospective approach to compare canopy lichen litter in adjacent, paired stands of rotation age (55-120 yr): one with and one without old-growth (>300 yr) remnant trees. We sampled three functional groups of lichens in 17 stands in western Oregon: alectorioid lichens, cyanolichens, and green-algal foliose lichens. Thirteen stands were low elevation (520-850 m) and four were mid-elevation (1220-1340 m). Biomass of cyanolichen and green-algal foliose lichen litter was greater in low-elevation sites, whereas alectorioid lichen litter biomass was greater in mid-elevation sites. Cyanolichens were absent from all mid-elevation sites. Biomass of alectorioid lichen and cyanolichen litter was greater in low-elevation sites with remnant trees than in those without remnant trees by 86% and 233%, respectively. The biomass of green-algal foliose lichen litter was 80% greater in mid-elevation sites without remnant trees than in those with remnant trees. Total lichen litter biomass was slightly, but not significantly, greater in stands with remnant trees at both low elevations (by 23%; ∼370 kg/ha standing biomass in remnant stands) and mid elevations (by 12%; ∼470 kg/ha standing biomass). Cyanolichen litter biomass was positively related to the number of remnant trees present; alectorioid and green-algal lichen litter biomass were negatively correlated with the density of trees in the regeneration cohort. Because retaining live remnant trees will differentially affect these three functional groups of macrolichens, managers must be clear as to their objectives before using green-tree retention as a tool to enhance biodiversity.
It is now clear that most of Europe, until at least Neolithic times, was covered with woodland of some kind. Palynological data from many sites has made this evident (e.g. Godwin 1975). It has also become clear recently that these early Flandrian forests would have been more open in character than was previously thought, at least in lowland areas. Numerous glades and open ‘lawns ‘ would have existed due to the presence of considerable numbers of large grazing and browsing herbivores such as the red deer and other deer species, the wild ox, the wild swine, and probably a species of wild horse. Bison were certainly also widespread in some parts of Europe. Grigson (1978) reviewed the evidence for the presence of numerous large herbivores in the Flandrian up to Atlantic times at least.
The volume is divided into four parts. The first provides definitions, significance and survival, including an overview of natural woodland types in Europe and North America. The second section examines temperate and boreal natural forests: overviews of selected virgin forests (Pisgah Forest - New Hampshire, Joyce Kilmer Memorial Forest - North Carolina, William L. Hucheson Memorial Forest - New Jersey, Bialowieza Forest - Poland, and Hoh and Queens Valleys - Washington); disturbance in natural woodland; succession after disturbance; structure and dynamics of old-growth forest; components of the forest; and wildlife of natural forest. Part three reviews virgin forest remnants; human impacts in North America; wildlife response to modification; and protection. The final section provides an overview of natural features in the conservation of British woodlands: woodland nature conservation - development, rationale and practice; British natural woodland; reconstructing British natural woodland; management of braodleaved woodland; design and management of upland conifer plantations; and priorities in woodland nature conservation. -S.R.Harris
The aim of the present study was to compare the physiological characteristics of various populations of the lichen Lobaria pulmonaria in Portugal and Sweden. For this, indirect markers of algal (photobiont) and fungal (mycobiont) activity were measured, as well as their CO2 gasexchange characteristics. Microclimatic conditions and the lichens growth performance in the two countries were compared using reciprocal transplantation. Two populations of L. pulmonaria represented each country: one collected from forest interior conditions and one from forest edge habitats. A non-transplanted “wild” population was also studied in each country, in order to evaluate any transplantation effects per se. The main hypothesis were that; 1) growth should be faster in Portugal due to higher light availability; 2) the energy use efficiency of lichen biomass gain should be similar for the native populations in their respective native habitat; 3) if the lichens were able to adapt to the environmental conditions in the foreign habitat this should be revealed as similar growth rates among all thalli transplanted at the same site, regardless of their origin. Physiologically, the Portuguese and Swedish populations were very similar, both concerning their CO2 gas exchange characteristics and distribution of resources between photo- and mycobiont tissue. Environmental conditions were more advantageous for L. pulmonaria growth in Portugal, i.e. higher photon flux densities and ambient temperatures when the lichens were wet and active, and a lower fraction of the active time occurring in darkness. However, despite similar physiological characteristics of all the studied populations, the Swedish lichens were not able to grow as well in Portugal as the native, while all populations had similarly low growth rates in Sweden.
The forest canopy is fundamentally important in biodiversity conservation and ecosystem function. Cryptogamic epiphytes are dominant tree bole and canopy elements in temperate and boreal forests, though remain neglected by mainstream forest ecology. This review makes ecological information on cryptogamic epiphytes available to a non-specialist audience, to facilitate their integration in forest biodiversity and ecosystem studies more generally. The review focuses specifically on lichen epiphytes, highlighting their diversity and ecosystem role. A principal task is to explore pattern and process in lichen epiphyte diversity – species composition and richness – therefore demonstrating the utility of lichens as an ecological model system. The review examines key themes in previous research. First, the extensive literature used to resolve species response to, and community turnover along environmental/resource gradients, consistent with the habitat niche. Second, the evidence for dispersal-limitation, which may constrain community composition and richness in isolated habitats. Third, these two processes – the habitat niche and dispersal-limitation – are used to explain stand-scale diversity, in addition to the role of neutral effects (habitat area). Fourth, the review moves from a taxonomic (pattern) to a functional (process) perspective, considering evidence for autogenic succession evidenced by competition and/or facilitation, and non-random trends in life-history traits. This functional approach provides a counter-point to an assumption that lichen epiphyte communities are unsaturated and non-competitive, a situation which would allow the long-term accumulation of species richness with temporal continuity. Finally, the review explores landscape-scale impacts on lichen epiphytes, with recommendations for conservation.
The "New Forestry" practice of green-tree retention is becoming an important management tool for publicly owned lands, yet few data exist to demonstrate that this tool can succeed at enhancing biodiversity. We addressed this issue by using a retrospective approach to compare canopy lichen litter in adjacent, paired stands of rotation age (55-120 yr): one with and one without old-growth (>300 yr) remnant trees. We sampled three functional groups of lichens in 17 stands in western Oregon: alectorioid lichens, cyanolichens and green-algal foliose lichens. Thirteen stands were low elevation (520-850 m) and four were mid-elevation (1220-1340 m). Biomass of cyanolichen and green-algal foliose lichen litter was greater in low-elevation sites, whereas alectotioid lichen litter biomass was greater in mid-elevation sites. Cyanolichens were absent from all mid-elevation sites Biomass of alectorioid lichen and cyanolichen litter was greater in low-elevation sites with remnant trees than in those without remnant trees by 86% and 233%, respectively. The biomass of green-algal foliose lichen litter was 80% greater in mid-elevation sites without remnant trees than in those with remnant trees. Total lichen litter biomass was slightly, but not significantly, greater in stands with remnant trees at both low elevations (by 23%; ∼370 kg/ha standing biomass in remnant stands) and mid elevations (by 12%; ∼470 kg/ha standing biomass). Cyanolichen litter biomass was positively related to the number of remnant trees present; alectorioid and green-algal lichen litter biomass were negatively correlated with the density of trees in the regeneration cohort. Because retaining live remnant trees will differentially affect these three functional groups of macrolichens, managers must be clear as to their objectives before using green-tree retention as a tool to enhance biodiversity.
Given C samples, with ni observations in the ith sample, a test of the hypothesis that the samples are from the same population may be made by ranking the observations from from 1 to Σni (giving each observation in a group of ties the mean of the ranks tied for), finding the C sums of ranks, and computing a statistic H. Under the stated hypothesis, H is distributed approximately as χ(C – 1), unless the samples are too small, in which case special approximations or exact tables are provided. One of the most important applications of the test is in detecting differences among the population means.** Based in part on research supported by the Office of Naval Research at the Statistical Research Center, University of Chicago.
Suitability of trees as hosts for epiphytic lichens are studied in a forest stand of size 25 ha. Suitability is measured as occupation probabilites which are modelled using hierarchical Bayesian approach. These probabilities are useful for an ecologist. They give smoothed spatial distribution map of suitability for each of the species and can be used in detecting high- and low-probability areas. In addition, suitability is explained by tree-level covariates. Spatial dependence, which is due to unobserved spatially structured covariates, is modelled through an unobserved Markov random field. Markov chain Monte Carlo method has been applied in Bayesian computation. The extensive spatial data consist of the occurrences of eight lichen species and one bryophyte on all of the 1253 potential host trees. In addition, coordinates of the trees and several tree characteristics have been recorded. The data have been analysed for four most abundant species: Lobaria pulmonaria, Nephroma bellum, Nephroma parile and Peltigera praetextata. The tree level parameters, subject to estimation, consist of the occurrence probabilities for each tree and for each lichen species. Model validation is discussed in detail and, in addition to Bayesian validation tools, the autologistic model and case-control design based on logistic regression have been suggested for validation of covariate effects. As a result we present suitability maps for the four lichen species. We observed, that among the observed tree covariates, the diameter at breast height (DBH) correlates with lichen occurrence. Our modelling approach has close connections to disease mapping in spatial epidemiology.
We used habitat models to forecast the frequency of occurrence of epiphytic lichen species in a forested landscape under two alternative plans: a literal application of standard prescriptions in the Northwest Forest Plan and a plan patterned in part after natural disturbance regimes. The plans were evaluated for the Blue River watershed in the Cascade Range of Oregon, USA. We used two model types: logistic regression and an ecological neighborhood model using a form of nonparametric regression (SpOcc; Species Occurrence Modeler). Both logistic regression and SpOcc successfully estimated the occurrence of the lichen Lobaria oregana in the current landscape, based on elevation and structural classes of forests. Structural classes were defined by combinations of (1) overstory retention of remnant trees, (2) young cohort age, and (3) stream position (upland vs. riparian). Lobaria oregana rapidly diminished in frequency in the landscape at elevations above 900-1000 m. Young, even-aged stands had little or no Lobaria oregana. Most of the other structural classes, however, were very similar in frequency of Lobaria. The differences in lichens between retention levels and between mature and old growth stands were very small compared to the differences with respect to elevation and clearcutting. Similar results, with varying importances of elevation and forest structure, were obtained for most of the 20 species with the strongest models. Many of these species were associated with old growth, and many were forecasted to be more frequent under either management plan than in the current landscape. This is a likely response to the reduction of even-aged management in this landscape. We recommend using SpOcc for flexible nonparametric fitting of species relationships to a multivariate habitat. SpOcc avoids the need to specify response functions and, because it is multiplicative rather than additive, automatically models responses to interactions among predictors.
Generation time and juvenile growth rates are important but poorly known parameters in lichen population biology. By using a noninvasive method, we aimed to quantify these variables in juvenile thalli of Lobaria pulmonaria (L.) Hoffm., L. scrobiculata (Scop.) D.C., and Pseudocyphellaria crocata (L.) Vain., in situ, on twigs of Picea abies (L.) H. Karst in boreal rainforests. Growth was monitored during the summer months (May–August, 106 d), as well as in the remaining part of the year (259 d), for each of two sequential years, by means of repeated photography and imaging analysis. The mean relative thallus-area growth rates were 0.53 ± 0.02, 0.41 ± 0.02, and 0.57 ± 0.04 mm2·mm–2·year–1 (mean ±SE), respectively, in the three species, equivalent to a yearly growth of 101 ± 5%, 70 ± 6%, and 121 ± 12%. Growth was much slower during the winter (0.09–0.12 mm2·cm–2·d–1) than in summer (0.19–0.27 mm2·cm–2·d–1). Relative growth rates significantly declined with increasing thallus size. Estimated generation times in L. scrobiculata and P. crocata, based upon the first observed formation of reproductive structures, were 15–22 and 9–13 years, respectively. Studied L. pulmonaria thalli produced no diaspores during the experiment, consistent with a generation time >17 years. The relative growth rates we measured and our estimated generation times are faster than those earlier recorded. Thus, our noninvasive method can estimate parameters needed to model population growth within a reasonable period of time. The rapid juvenile development implies that the growth rates and generation times are unlikely to be the limiting factors that exclude these lichens from young forests.
The influence of forest management on species richness and composition of epiphytic macrolichens was studied on beech stems in two differently managed stands in northern Italy: (1) mixed-multilayered stand with silver fir, spruce and beech, managed by selective-cutting and (2) pure beech stand, intensively managed by shelterwood-cutting. Macrolichens and easily identifiable crustose lichens were surveyed on 150 randomly selected beech trees in 10 management units. Trees of the two stands significantly differed in lichen composition, but not in species richness. However, most of the rare species were exclusive of the sites managed by selective-cutting. The lichen flora of mixed stands mainly included suboceanic species-sensitive to forest management and habitat modification; that of pure stands was dominated by generalist species common in disturbed habitats. Lobaria pulmonaria is suggested as a signal species for rapidly assessing the conservation importance of forests. Some practical suggestions are given to enhance lichen conservation in intensively managed stands.
We attempted to elucidate the roles of β‐diversity components and similarity in shaping L obaria pulmonaria lichen communities in I talian forests to provide scientific tools for improving their long‐term conservation.
A total of 20 sites were selected by stratified random sampling, including five chestnut forests, seven beech–silver fir forests and eight oak forests distributed across 10 administrative regions of I taly. Site selection was based on a national data base including all the available records of L. pulmonaria in I taly. In each forest, four plots were randomly placed, and in each plot, 5–6 trees were randomly selected for lichen sampling. For each forest and plot, meaningful predictors of lichen patterns were quantified. In particular, factors indicative of both geographic conditions and forests structure were considered. The SDR simplex approach was used to estimate the relative importance of similarity ( S ), relative species replacement ( R ) and relative richness difference ( D ) to β‐diversity and similarity, while a hierarchical partitioning ( HP ) method was used to evaluate the relative importance of environmental predictors in explaining their patterns.
A total of 201 lichens and three nonlichenized fungi were found, including 51 species of conservation concern. The components of β‐diversity and similarity contributed to shaping L. pulmonaria communities at both forest and plot scales across Italy, resulting in nearly random compositions, that is, the species set on each tree was a random sample from the available species pool. Species replacement and similarity were generally associated with forest structure predictors, while richness difference was mainly associated with geographic predictors. The implication of this is that the long‐term conservation of L . pulmonaria communities could be promoted by maintaining scattered nodes and appropriate habitat traits, especially in large forested landscapes where species turnover is higher.
Synthesis . In this work, we used a new approach for analysing a countrywide data set improving the ecological understanding of the dynamics regulating epiphytic communities. In particular, this study improves the understanding of the contribution of different components of diversity across two spatial scales and evaluates the relative importance of environmental predictors in explaining variation of each diversity component.
It is necessary to understand how environmental changes affect plant fitness to predict survival of a species, but this knowledge is scarce for lichens and complicated by their formation of sexual and asexual reproductive structures. Are the presence and number of reproductive structures in Lobaria pulmonaria, a threatened lichen, dependent on thallus size, and is their formation sequential? Does any size-dependence and sequential formation vary along a climate gradient? Generalized linear mixed models were used to explore the effect of environmental predictors on the size and presence/abundance of each reproductive structure and to determine the probability of a given-sized thallus to develop any reproductive structure. The largest individuals are more likely to develop reproductive structures, and the lichen uses a mixed strategy of early asexual reproduction and late sexual. Macro and microclimatic variables also influenced reproductive capacity. Relationships among climate conditions and lichen size and reproductive capacity can compromise the future viability of the species in the most southern populations of Europe.
Successful biodiversity conservation needs to be based on reliable data regarding the distribution and abundance of species. Red Lists summarize the status of rare and declining species. Here we present the first detailed survey (10 m x 10 m resolution) of nationally red-listed bryophytes and lichens at stand level in boreal forests. 30 managed forest production stands in boreal Sweden, soon to be harvested, were surveyed in detail regarding red-listed bryophytes and lichens. On the 180 ha totally investigated, 33 red-listed species were found, representing 35% of all forest red-listed bryophytes and lichens so far recorded from this part of Sweden. The mean number of red-listed species per stand was 10 and varied between 5 and 16. Excluding three species which were so common that, given the time-limit, it was not possible to record all of their occurrences, there were on average 6 number of observations ha -1. The presence and density exceed those earlier found in 'key habitats', defined as hot-spots for red-listed species. Almost all observations were made on trees, with 48% on living trees and 52% on dead. Altitude, area and stem volume explained 67% of the red-list species density. The results highlight the importance of unprotected areas for rare and declining species and point to a hitherto unacknowledged high biodiversity value of mature managed boreal forest stands, shaped by a less intense forestry than today's. It also raises questions regarding the use of red-listed species to identify areas of importance to biodiversity. Objective and systematic surveys of red-listed species in the forest landscape, including younger stands, are urgent.
n lichen symbiosis, fungal and algal partners form close associations, often codi- spersed by vegetative propagules. Due to the particular interdependence, processes such as colonization, dispersal or genetic drift are expected to result in congruent patterns of genetic structure in the symbionts. To study the population structure of an obligate symbiotic system in Europe, we genotyped the fungal and algal symbionts of the epiphytic lichen Lobaria pulmonaria at eight and seven microsatellite loci, respec- tively, and analysed about 4300 L. pulmonaria thalli from 142 populations from the species’ European distribution range. Based on a centroid approach, which localizes centres of genetic differentiation with a high frequency of geographically restricted alleles, we identified the South Italy–Balkan region as the primary glacial refugial area of the lichen symbiosis. Procrustean rotation analysis and a distance congruence test between the fungal and algal population graphs indicated general concordance between the phylogeographies of the symbionts. The incongruent patterns found in areas of postglacial recolonization may show the presence of an additional refugial area for the fungal symbiont, and the impact that horizontal photobiont transmission and different mutation rates of the symbionts have on their genotypic associations at a continental scale.
A data set of growth in 600 Lobaria pulmonaria transplants in three successional forest stands was reanalysed after a subsequent quantification of their reproductive effort. This epiphytic lichen reproduces mainly by asexual and symbiotic diaspores (soredia and/or isidia) that simultaneously disperse the fungal and algal partners. L. pulmonaria showed a clear trade-off between growth and reproductive efforts. Increased reproductive efforts decreased the area growth to a larger extent than the weight gain, meaning that reproduction increased with increasing lobe thickness and presumably increasing lobe age. The growth reduction caused by reproduction is so strong that future ecological and physiological lichen studies should consider the reproductive stage or standardize the amount of asexual diaspores in future experiments.ZusammenfassungEin Datensatz zum Wachstum von 600 Lobaria pulmonaria-Transplantaten in drei sukzessiven Waldbeständen wurde reanalysiert, nachdem eine anschließende Quantifizierung ihres Reproduktionsaufwands gemacht wurde. Diese epiphytische Flechte reproduziert sich hauptsächlich durch asexuelle und symbiotische Diasporen (Soredien und/oder Isidien), die gleichzeitig den Pilz- und Algenpartner verbreiten. L. pulmonaria zeigte einen deutlichen „trade-off“zwischen Wachstum und Reproduktionsaufwand. Ein zunehmender Reproduktionsaufwand verminderte das Flächenwachstum in einem größeren Ausmaß als die Gewichtszunahme. Dies bedeutet, dass die Reproduktion mit zunehmender Thallusdicke und wahrscheinlich zunehmendem Thallusalter zunahm. Die Reduktion der Größe, die durch Reproduktion verursacht wird, ist so stark, dass zukünftige ökologische und physiologische Flechtenuntersuchungen die Reproduktionsstadien berücksichtigen oder die Anzahl der asexuellen Diasporen in zukünftigen Experimenten standardisieren sollten.
ROSE, F., 1988. Phytogeographical and ecological aspects of Lobarion communities in Europe. The Lobarion communities in Europe are reviewed on the basis of field surveys by the author from south-west Norway to the Pyrenees, Tuscany and Austria. Lobarion communities are still widespread in most montane forests, but in the lowlands are now largely restricted to the Atlantic coastal zone, evidently through forest management practices and air pollution. Evidence for the decline is discussed and causes are reviewed. The major species occurring in these communities in different regions of Europe are tabulated and this reveals interesting geographical patterns. The alliance is appropriately divided into three associations, one being newly proposed here for southern European communities with species drawn from the Xanthorion.
The ability of cyanolichens to sustain growth in even-aged forests that develop after clear-cut harvesting is a major conservation biology concern in British Columbia's inland rainforest. This and other conservation issues have led to proposals advocating partial-cut rather than clear-cut harvesting to better maintain the structures that support biodiversity in old-growth forest stands. However, evaluating the potential impacts of alternative harvesting practices cannot occur without first understanding lichen growth responses to the existing range of natural variability in canopy structure. Using transplant experiments with thalli of Lobaria pulmonaria (a tripartite foliose cyanolichen), we evaluate growth responses to canopy structure in both naturally occurring 120 year old small-patch even-aged stands and in adjacent old-growth uneven-aged forest stands. Canopy microclimate was also measured in old-growth reference trees, allowing calculation of energy conversion efficiency for old-growth L. pulmonaria thalli. Growth rates of L. pulmonaria transplants showed a strong correlation with canopy light transmission (CLT). Mean annual lichen dry matter gain over the 2-year measurement period ranged from less than 5% on branches in closed canopy even-aged stands (<1 mol m À2 day À1 CLT) to near 20% on branches under canopy gaps in old-growth stands (>18 mol m À2 day À1 CLT). Intercepted irradiance of hydrated L. pulmonaria thalli (I wet) under old-growth stand conditions was 24.7 and 45.5 MJ m À2 annually in years 2 and 3 of the study, resulting in an energy conversion efficiency of 1.33 and 0.61%, respectively. Open sky (gap fraction) above lichen transplants in old-growth stands was much greater than that found in even-aged stands, allowing for longer duration sunfleck events in the lower canopy of the old-growth forest stands. These findings suggest that the creation of small openings by partial-cut harvesting in the inland rainforest may result in conditions favourable to continued growth of the dominant canopy cyanolichen, L. pulmonaria. They also support existing concerns about future cyanolichen growth in even-aged forests regenerating after clear-cut harvesting. # 2007 Elsevier B.V. All rights reserved.
Question: What are the responses of epiphytic lichens to the intensity of management along a large environmental gradient in Mediterranean Quercus forests?
Location: Central Spain.
Methods: This study was carried out on 4590 trees located in 306 forest stands dominated by Quercus faginea or Quercus ilex ssp. ballota. The effect of forest management and other predictor variables on several species diversity indicators were studied. Variables modelled were total species richness, cyanolichen richness and community composition. A large number of predictor variables were included: forest fragmentation (patch size, stand variability), climate and topographic (altitude, slope, sun radiation, annual rainfall and mean annual temperature) and intensity of management. General linear models and constrained ordination techniques were used to model community traits and species composition, respectively.
Results: Total richness and especially cyanolichens richness were significantly and negatively affected by the intensity of management. Lichen composition was influenced by management intensity, climatic and topographic variables and stand variability.
Conclusions: In Mediterranean forests, human activities related to forestry, agricultural and livestock use cause impoverishment of lichen communities, including the local disappearance of the most demanding species. The conservation of unmanaged forests with a dense canopy is crucial for lichen diversity.
Questions: What factors limit the distribution of epiphytic lichens and bryophytes at plot and tree level in beech forests? At what ages do epiphytic species, and species of conservation concern in particular, occur along a chronosequence of beech?
Location: South-west Sweden.
Method: Five hundred and seventy-one age-determined trees from 37 plots distributed among 29 beech-dominated stands were surveyed along with a number of environmental (16) and substrate (seven) variables in a landscape of ca. 550 ha. Non-metric multidimensional scaling (NMS) and indicator species analysis (ISA) were used for data analysis.
Results: Plots containing old trees, confined to the base of slopes and with low impacts of recent forestry (thinning), generally had a high richness of species of conservation concern. Richness of common species and red-listed bryophytes were mostly related to the surveyed bark area. At tree level, primary factors explaining both species richness and composition were age, diameter at breast height and moss cover. There was a gradual replacement of tree age ranges for 58 lichens and 37 bryophytes along the chronosequence of beech. Red-listed lichens favoured damaged beech trees (≥180 years), whereas red-listed bryophytes were found on old and young stems in dense stands.
Conclusions: Tree age exerts a profound influence on epiphytic lichens and bryophytes growing on beech. Many of the habitat specialists were found mainly on old beech because they inhabit specific substrates that occur on older trees. The association to high tree age commonly excludes red-listed lichens from conventionally managed beech forests with a 100- to 140-year rotation period.
Questions
How do tree age, microhabitat characteristics and epiphytic competitors affect the occurrence of crustose lichens associated with old oaks? How do microhabitat characteristics and microclimate affect the cover of competitors (bryophytes and macrolichens)? How do microhabitat characteristics correlate with microclimatic variables?
Location
Southeast Sweden.
Methods
Eight crustose lichen species were surveyed on 165 Quercus robur trees, 17–478 years old, at three study sites. The occurrence patterns of these species were examined at two spatial scales: among trees and within trees. Occurrence patterns within trees were examined in 10 cm × 10 cm plots at all four cardinal aspects at different heights from 0.5 to 4.5 m above the ground.
Results
At the tree level, age‐related factors were the most important predictors of species occurrence. All species were more frequent on trees > 100 years than on younger trees. At the plot level, the frequency of occurrence increased with increasing bark crevice depth. The frequencies of all study species decreased with increasing cover of bryophytes. Bryophytes were in turn more frequent in plots that were exposed to rainwater and showed a low evaporation rate. Patches most exposed to rainwater were directed upwards, and the lowest evaporation rates occurred on the northern side of the trunks.
Conclusions
For many crustose lichens the association with old oak trees seems at least partly to depend on their preference for the deep bark crevices that only occur on old trees. Trees represent epiphyte habitat patches that differ in size due to within‐tree variability in habitat quality, such as bark crevice depth and microclimate. This study shows that variability at a finer scale, within habitat patches, contribute to explain species occurrence patterns at habitat patch level.
To maintain biodiversity in managed forests we must understand how forestry affects various organisms across a wide range of spatial and temporal scales. We compared landscape structure, forest structure, and species richness and abundance of epiphytic macrolichens in three pairs of natural and managed boreal forest landscapes. Study landscapes (2500 ha) were located within and adjacent to three of the largest forest reserves in Sweden (Reivo, Muddus, Jelka). The structural heterogeneity within landscapes was higher in managed forests whereas within-stand structural heterogeneity was higher in natural landscapes. Species richness of macrolichens at the stand level (sample plot) was 23% higher in natural forests but there was no difference at the landscape level. Most (86%) of the common species were more frequent in natural landscapes. Lichen abundance (estimated by lichen litter) was two times higher in natural than in managed landscapes, 5.6 and 2.7 kg ha-1 forest (pooled data), respectively. Both species richness and abundance were negatively related to cutting level (number and basal area of cut stumps) and positively related to stand variables (stand age, stem density and basal area). Lichen-rich forest stands were more numerous but covered a smaller area and were more isolated in managed landscapes. This may in turn have important consequences for dispersal of lichen propagules to second-growth forests. In conclusion, the results suggest that effects of forestry on epiphyte diversity and abundance are strongly related to the spatial scale (stand or landscape). To enhance biodiversity in managed forests we must increase structural heterogeneity at the whole range of spatial and temporal scales.
Questions: Can a statistical model be designed to represent more directly the nature of organismal response to multiple interacting factors? Can multiplicative kernel smoothers be used for this purpose? What advantages does this approach have over more traditional habitat modelling methods?
Methods: Non-parametric multiplicative regression (NPMR) was developed from the premises that: the response variable has a minimum of zero and a physiologically-determined maximum, species respond simultaneously to multiple ecological factors, the response to any one factor is conditioned by the values of other factors, and that if any of the factors is intolerable then the response is zero. Key features of NPMR are interactive effects of predictors, no need to specify an overall model form in advance, and built-in controls on overfitting. The effectiveness of the method is demonstrated with simulated and real data sets.
Results: Empirical and theoretical relationships of species response to multiple interacting predictors can be represented effectively by multiplicative kernel smoothers. NPMR allows us to abandon simplistic assumptions about overall model form, while embracing the ecological truism that habitat factors interact.
Two populations of the lichen Lobaria pulmonaria, growing on aspens and goat willows in 12 and 20 km2 study areas of boreal forest in Finland, were surveyed thoroughly to investigate the factors influencing the spatial distribution of the lichen. In one study area, where forestry has been intensive and old-growth forest is highly fragmented, L. pulmonaria was sparse and grew mostly on willows. In contrast, a large and continuous virgin forest area supported a higher incidence of L. pulmonaria, with the lichen being common on both aspens and willows. In both study areas, the distributions of aspen and willow were clumped over the scales of 100–1000 m. The spatial pattern of L. pulmonaria was more clumped in the managed forest than in the virgin forest. The reduced incidence of the lichen on aspens in the managed area was attributed to a disruption of habitat continuity and small average tree size. There was no comparable reduction in the incidence on willows, probably because the willow had a very aggregated distribution in the managed area, which probably facilitated local colonization of the lichen. Presence of the lichen was significantly related to size-corrected local density of aspen and willow trees as well as to spatial connectivity to neighboring lichen-occupied trees.
All Swedish forest land is at present being surveyed with the aim of mapping woodland key habitats which have an estimated number of ca. 70 000. An untested requirement of these habitats is that they should contain red-listed species. In order to investigate if they fulfill their aim, an inventory of nationally red-listed bryophytes and lichens was performed in ca. 120 randomly selected woodland key habitats distributed throughout the country. The species were recorded in line transects, covering the whole surface of the habitats. The mean number of red-listed species per habitat was 0.7 for bryophytes and 1.4 for lichens with 11 species at the richest site and 71% of the sites having at least one species. Nemoral forests and coniferous forests were the most species-rich habitat types. The habitats of northern Sweden were more species rich than the southern ones. There were weak correlations between presence of bryophytes and lichens. The study shows that a majority of the woodland key habitats contain red-listed bryophyte and lichen species. Further studies are needed in order to record more organism groups and to compare the woodland key habitats with the surrounding matrix forests.
By surveying and re-surveying 12 forest sites in southern Sweden for the epiphytic lichen Lobaria pulmonaria with a 9-year interval, and measuring tree-related habitat quality variables, we have investigated whether the local distribution of the lichen is limited by poor dispersal capacity or by habitat quality. Dispersal distances were measured indirectly as the distances between colonised trees and the nearest trees occupied by L. pulmonaria in both 1992 and 2001. To compare habitat quality between trees occupied by L. pulmonaria and neighbouring control trees, we recorded tree species and measured age and growth rate of trees, light conditions, bark structure and bryophyte cover. The estimated mean dispersal distance was 35 m, with a recorded maximum of 75 m. Occupied trees were larger and had a larger cover of bryophytes than unoccupied trees of similar size. The results indicate that dispersal capacity probably is the most important factor in limiting the local distribution of L. pulmonaria, but habitat-quality factors may be important on a smaller spatial scale.