Article

Mature non-native black-locust (Robinia pseudoacacia L.) forest does not regain the lichen diversity of the natural forest

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Abstract

The responses of lichens to habitat changes caused by invasive trees are poorly understood. Invasive forest trees may impact epiphytic lichens by altering both substrate and stand conditions. Previous research has demonstrated that black locust invasion, associated with intensive exploitation of native oak forests, led to dramatic shifts in lichen composition. However, it is not clear if, along with stand aging, black locust formations regain forest species. The main aim of this study was to test whether the succession of black locust stands promotes a lichen succession leading to assemblages in mature black locust stands which are similar to those of native forests. To test the influence of macro-environmental conditions, we performed the study in two bioclimatically different areas of Italy. The epiphytic lichen biota of native oak and chestnut stands was compared with that of black locust stands of different successional stages. In both regions we did not find a lichen succession in black locust stands of different age, and mature black-locust stands did not recover the diversity of epiphytic species, which are lost by the replacement of the native forests by black locust. The absence of this pattern may be caused by factors related to the management of black locust stands, and to bark features. The different bioclimatic conditions between the two study areas may explain differences in the lichen biota of native forests, while that of black locust stands tend to be similar between regions, suggesting that forest habitat changes associated with the spread of black locust could decrease lichen diversity among bioclimatically different regions.

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... Epiphytic lichen communities of invasive Robinia stands can show pronounced differences from native forest stands (Nascimbene, Nimis & Benesperi 2012). In Italy, for example, the lichens Candelaria concolor (Dickson) Stein, Candelariella reflexa (Nyl.) ...
... Lettau, Hyperphyscia adglutinata (Florke) Mayrh. & Poelt and Physcia adscendens were among the most common species on false acacia bark (Nascimbene, Nimis & Benesperi 2012). ...
... Other effects of false acacia invasion include a pronounced decrease in epiphytic lichen diversity (Nascimbene & Marini 2010;Nascimbene, Nimis & Benesperi 2012). Moreover, ectomycorrhiza is affected adversely by false acacia presence, as both species number and abundance decrease in invaded forests (Taniguchi et al. 2007). ...
Article
1. This account presents information on all aspects of the biology of Robinia pseudoacacia L. that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, and history and conservation. 2. Robinia pseudoacacia, false acacia or black locust, is a deciduous, broad-leaved tree native to North America. The medium-sized, fast-growing tree is armed with spines, and extensively suckering. It has become naturalized in grassland, semi-natural woodlands and urban habitats. The tree is common in the south of the British Isles and in many other regions of Europe. 3. Robinia pseudoacacia is a light-demanding pioneer species, which occurs primarily in disturbed sites on fertile to poor soils. The tree does not tolerate wet or compacted soils. In contrast to its native range, where it rapidly colonizes forest gaps and is replaced after 15–30 years by more competitive tree species, populations in the secondary range can persist for a longer time, probably due to release from natural enemies. 4. Robinia pseudoacacia reproduces sexually, and asexually by underground runners. Disturbance favours clonal growth and leads to an increase in the number of ramets. Mechanical stem damage and fires also lead to increased clonal recruitment. 5. The tree benefits from di-nitrogen fixation associated with symbiotic rhizobia in root nodules. Estimated symbiotic nitrogen fixation rates range widely from 23 to 300 kg ha−1 year−1. The nitrogen becomes available to other plants mainly by the rapid decay of nitrogen-rich leaves. 6. Robinia pseudoacacia is host to a wide range of fungi both in the native and introduced ranges. Megaherbivores are of minor significance in Europe but browsing by ungulates occurs in the native range. Among insects, the North American black locust gall midge (Obolodiplosis robiniae) is specific to Robinia and is spreading rapidly throughout Europe. 7. In parts of Europe, Robinia pseudoacacia is considered an invasive non-indigenous plant and the tree is controlled. Negative impacts include shading and changes of soil conditions as a result of nitrogen fixation.
... Matteucci et al. (2012) , compare coppice chestnut forests with chestnut orchards managed for fruit production, while Giordani (2012) compares intensively managed coppice with aged coppice and old-growth forest. Nascimbene and Marini (2010), and Nascimbene et al. (2012a) compare remnant oak fragments managed by single tree selection or coppice with black-locust stands managed with short rotation cycles. In general, higher lichen diversity is related with lower managemen t intensity, even if in some cases nonintensively managed forests (e.g. ...
... ). Two studies exploring the effect of the replacement of coppice forests composed of native species (oaks and chestnut) by pure black locust formations managed by short rotation cycles highlight a loss of lichen diversity and a process of species homogenization (Nascimbene and Marini, 2010; Nascimbene et al., 2012a). The shift from a shelterwood system to selective cut, and the prolonga tion of the rotation period in high forests and coppice forest is not sufficient for ensuring long-term lichen conservation. ...
... Moreover , some studies highlighted the importance for lichen diversity of native deciduous trees such as oaks, hornbeam, and beech (e.g. Boch et al., 2013; Hauck et al., 2013; Király et al., 2013; Nascimbene et al., 2012a ). The strong dependence of epiphytic lichens on host tree species may expose them to threats deriving from emerging infectious diseases (EIDs). ...
Article
This review aims at summarizing literature on epiphytic lichens in relation with forest management in temperate deciduous forests of Europe, including suggestions for mitigating the impact of forestry and stimulating further research. The review is focused on environmental factors that directly depend on, or that are known to interact with forest management, such as tree (and forest) age and size, tree species composition, large scale factors (e.g. climate and air pollution), landscape context, and past forest history. The literature demonstrates the sensitiveness of epiphytic lichens to forestry: forest management, and especially the shelterwood system, is a source of threat for many forest-dwelling lichens. Several studies include explicit recommendations for mitigating the effect of forestry. The main ones are: (a) selective cutting should be preferred to the shelterwood system; (b) the negative effect of the shelterwood system could be mitigated by the extension of the rotation period and by the retention of groups of mature trees at the final harvest; (c) the creation of stands with intermediate canopy openness should be promoted; (d) logs and snags should be retained in production forests; (e) large old trees should be maintained in production forests and some of them left until dead and decomposed (“eternity trees”); (f) tree species diversity should be maintained in mixed stands; (g) forest fragments around existing species-rich oldgrowth remnants should be maintained, to create a network of set-aside areas; (h) indicator species could be used for a rapid assessment of forest sites worthy of conservation. However, some topics are still scarcely explored, such as the case of (a) coppice forests, (b) the evaluation of the landscape context and forest history, (c) dead wood-dwelling communities and the role of different types of dead wood for lichen conservation, (d) the effects of emerging infectious diseases, and (e) the use of indicator species to assess the conservation importance of forests. Other research approaches, that are still scarcely developed for lichens, may contribute further information for a more comprehensive understanding of the processes that are behind observed patterns of lichen diversity, such in the case of the evaluation of the role of species functional traits in determining the dispersal ability and the response of lichens to environmental factors.
... Rédei et al., 2014) which outcompetes other plants, thus reducing local biodiversity (e.g. Benesperi et al., 2012;Nascimbene et al., 2012;Sitzia et al., 2012). Furthermore it shows a homogenizing effect on species composition of both tree and herb layers (e.g. ...
... On the other hand, Robinia stands are often mixed, light and heterogeneous in SE, thus the impact of Robinia is mitigated by share of other native trees, such as oaks. The homogenizing effect of the species is controversial, particularly in rural landscapes (Sitzia et al., 2012), but the species composition (Nascimbene et al., 2012;Campagnaro et al., 2018b;Allegrezza et al., 2019) and ecosystem processes (Sitzia et al., 2018) are always changed in comparison with native tree stands. Diverse forms of silvopastoral management (Rigueiro-Rodríguez et al., 2009) combined with coppicing (Vacik et al., 2009) are often used due to historical reasons, especially in Balkan countries. ...
Article
Knowledge of the species composition of invaded vegetation helps to evaluate an ecological impact of aliens and design an optimal management strategy. We link a new vegetation analysis of a large dataset to the invasion history, ecology and management of Robinia pseudoacacia stands across Southern Europe and provide a map illustrating Robinia distribution. Finally, we compare detected relationships with Central Europe. We show that regional differences in Robinia invasion, distribution, habitats and management are driven both by local natural conditions (climate and soil properties, low competitive ability with native trees) and socioeconomic factors (traditional land-use). Based on the classification of 467 phytosociological relevés we distinguished five broad vegetation types reflecting an oceanity-continentality gradient. The stands were heterogeneous and included 824 taxa, with only 5.8% occurring in more than 10% of samples, representing mainly hemerobic generalists of mesophilous, nutrient-rich and semi-shady habitats. The most common were dry ruderal stands invading human-made habitats. Among native communities, disturbed mesic and alluvial forests were often invaded throughout the area, while dry forests and scrub dominated in Balkan countries. Continuous, long-term and large-scale cultivation represent a crucial factor driving Robinia invasions in natural habitats. Its invasion should be mitigated by suitable management taking into account adjacent habitats and changing cultivation practices to select for native species. Robinia invasion has a comparable pattern in Central and Southern Europe, but there is a substantial difference in management and utilization causing heterogeneity of many South-European stands.
... Epiphytic lichen diversity is influenced by the tree species they inhabit, and the environment surrounding that tree (Bäcklund et al., 2016). It is also related to forest structure and dynamics (e.g.: Neitlich & McCune, 1997;McCune, 2000;Hedenås & Ericson, 2008;Johansson, 2008;Rogers & Ryel, 2008;. Several environmental factors relevant to dispersal, establishment, and maintenance of epiphytic lichens are affected by forest management (Johansson, 2008;Ellis, 2012). ...
... Biodiversity conservation strategies which ignore these highly specialized organisms are likely to miss their principal aim (Bergamini et al., 2007). Despite their ecological importance and their value as environmental quality indicators (Griffin & Conran, 1994;Quine & Humphrey, 2010;Martínez et al., 2011;Nascimbene et al., 2012) relatively few studies have focused on lichen to ascertain the consequences of habitat loss or forestry intensification . Also, these studies mainly refer to boreal or template regions , but there is a lack of knowledge about Macaronesian woodlands despite of human activities in the past. ...
... Epiphytic lichen diversity is influenced by the tree species they inhabit, and the environment surrounding that tree (Bäcklund et al., 2016). It is also related to forest structure and dynamics (e.g.: Neitlich & McCune, 1997;McCune, 2000;Hedenås & Ericson, 2008;Johansson, 2008;Rogers & Ryel, 2008;. Several environmental factors relevant to dispersal, establishment, and maintenance of epiphytic lichens are affected by forest management (Johansson, 2008;Ellis, 2012). ...
... Biodiversity conservation strategies which ignore these highly specialized organisms are likely to miss their principal aim (Bergamini et al., 2007). Despite their ecological importance and their value as environmental quality indicators (Griffin & Conran, 1994;Quine & Humphrey, 2010;Martínez et al., 2011;Nascimbene et al., 2012) relatively few studies have focused on lichen to ascertain the consequences of habitat loss or forestry intensification . Also, these studies mainly refer to boreal or template regions , but there is a lack of knowledge about Macaronesian woodlands despite of human activities in the past. ...
Article
Mankind has been altering native forests in Macaronesia for at least five centuries. Forestry practices are known to reduce biodiversity due to habitat loss, fragmentation and alteration. To assess the potential of plantations to provide habitat for epiphytic lichens in comparison with native forests, we examined three types of forest in the Canary Islands: laurel forest (native forest) and two monospecific plantations of Pinus radiata and Eucalyptus globulus. Epiphytic lichen diversity was evaluated using a methodology of species richness and lichen diversity values (LDV). Our results demonstrate that the conversion of laurel forests to monoculture plantations of exotic tree species decreases lichen diversity and alters lichen community composition. Our findings hightlight how native epiphytic lichens from the cloud forest cannot survive under the same climatic conditions if the host plant community is changed.
... '' Ã'' marks those studies that include the effect of forest or tree age among their main topics; ''+'' marks those studies that include practical suggestions for forest management. . Two studies exploring the effect of the replacement of coppice forests composed of native species (oaks and chestnut) by pure black locust formations managed by short rotation cycles highlight a loss of lichen diversity and a process of species homogenization (Nascimbene and Marini, 2010;Nascimbene et al., 2012a). The shift from a shelterwood system to selective cut, and the prolonga tion of the rotation period in high forests and coppice forest is not sufficient for ensuring long-term lichen conservation. ...
... Moreover, some studies highlighted the importance for lichen diversity of native deciduous trees such as oaks, hornbeam, and beech (e.g. Boch et al., 2013;Hauck et al., 2013;Király et al., 2013;Nascimbene et al., 2012a ). ...
... A study in Austria found that oak-hornbeam forests, after chestnut-beech formation, are at a high risk of future invasions due to climate change (Kleinbauer, Dullinger, Peterseil, & Essl 2010). This issue of oak habitat type invasion by alien tree species was also highlighted as a concern in the Continental biogeographical region of many countries (Chmura 2004;Nascimbene & Marini 2010;Nascimbene, Nimis, & Benesperi 2012). Furthermore, xerothermic mixed oak forests suffer from the invasion by R. pseudoacacia and A. altissima in eastern Austria (Walter, Essl, Englisch, & Kiehn 2005). ...
... For example, plant and other taxa community composition, a common indicator of the structure of forest habitat types, was reported to be affected by the invasion of alien tree species(Buchholz, Tietze, Kowarik, & Schirmel 2015;Hanzelka & Reif 2015;2016;Krebs 2012;Nascimbene & Marini 2010;Reif et al., 2016;Staska, Essl, & Samimi 2014;Terwei et al., 2016). Furthermore, the impact on habitat functions can be demonstrated by changes in the functional traits of species communities, such as the increase in nitrophilous species(Nascimbene, Nimis, & Benesperi 2012;Staska, Essl, & Samimi 2014), but also in the scaling up across trophic levels of impacts with the modification of food webs typical of the native habitats.However, these examples showed that several taxa can be affected differently and that contrasting impacts may be observed. Usually, plant diversity is considered to be affected by alien tree species, but this may depend on several factors such as the threatened native forest type characteristics and the geographical context. ...
Article
Invasive alien species are a threat to protected areas, species, and habitats worldwide. At the European level, the control of invasive alien species is a major goal of the EU Biodiversity Strategy, and a cornerstone, in this sense, is the Regulation (EU) no.1143/2014 on invasive alien species. In this study, we focus on the Alpine and Continental biogeographical regions of Europe (defined in art. 1 of the Habitats Directive; 92/43/EEC), and aim to give an overview ofthe main protected forest habitattypes threatened by invasive alien species, and focus on five major invasive alien tree species (Acer negundo, Ailanthus altissima, Prunus serotina, Quercus rubra, and Robinia pseudoacacia).We considered the assessment reports under Article 17 ofthe Habitats Directive for the period 2007–2012, and six documents on the interpretation of habitats,to identify those most threatened by invasive alien species and in particular by the five invasive alien trees. We also assessed selected examples of impacts by these alien tree species on different species groups within Natura 2000 sites to highlight potential effects on biodiversity. Riparian forest habitats and oak dominated woodlands are among the most prone to invasion within the two biogeographical regions. A. altissima and R. pseudoacacia are the most reported invasive alien trees in these protected forest habitat types. Furthermore, examples of the impacts of these tree species have indicated potential detrimental effects on forest habitats structure and functions, and on single species listed in the Habitats and Birds Directives. In conclusion, we emphasise the need for effective management and systematic monitoring of these five invasive alien tree species within Natura 2000 sites.
... Castanea) are colonized by acidophilous or subneutrophilous species such as Graphis scripta, Opegrapha atra, and Opegrapha rufescens, such as in our study area, eutrophication may lead to the replacement of such species by nitrophilous ones in light-flooded conditions, or, in very shaded conditions, to their replacement by free-living algae (Hauck and Wirth 2010). Interestingly, similar results were observed by Nascimbene and Marini (2010) and Nascimbene et al. (2012), which investigated the responses of lichen communities to habitat changes caused by the invasion of Robinia pseudoacacia (black-locust), an alien tree with N-fixing activity, which showed that black-locust invasion led to a shift in lichen communities from assemblages composed by acidophilous, shade-tolerant and N-sensitive species to lichen communities mainly formed by N-tolerant species. The reasons can be the excessive thinning and consequent canopy openness and its bark features, such as the high buffering and water retention capacity and the nutrient content, likely enhanced by an interaction with the soil, whose chemistry is influenced by the nitrogen fixation activity of the bacteria associated with the roots (Nascimbene et al. 2012). ...
... Interestingly, similar results were observed by Nascimbene and Marini (2010) and Nascimbene et al. (2012), which investigated the responses of lichen communities to habitat changes caused by the invasion of Robinia pseudoacacia (black-locust), an alien tree with N-fixing activity, which showed that black-locust invasion led to a shift in lichen communities from assemblages composed by acidophilous, shade-tolerant and N-sensitive species to lichen communities mainly formed by N-tolerant species. The reasons can be the excessive thinning and consequent canopy openness and its bark features, such as the high buffering and water retention capacity and the nutrient content, likely enhanced by an interaction with the soil, whose chemistry is influenced by the nitrogen fixation activity of the bacteria associated with the roots (Nascimbene et al. 2012). ...
Article
In this study, we investigated whether ammonia emissions from industrial composting of organic waste may influence the surrounding environment, using lichens as bioindicators. To this purpose, samples of N-tolerant and N-sensitive lichens, namely Xanthoria parietina and Evernia prunastri, were transplanted for 1-3 months along transects at increasing distance (0-400 m) from a composting facility in Tuscany, Italy. Atmospheric concentrations of ammonia were measured using passive samplers. The physiological response of lichen transplants was investigated by means of the photosynthetic efficiency (measured as chlorophyll a fluorescence emission), the integrity of cell membranes (measured as electrolyte leakage), and sample viability (measured as enzymatic activity of dehydrogenase). Epiphytic lichen communities were investigated using biodiversity indices. The results showed decreasing concentrations of ammonia, from 48.7 μg/m(3) at the composting facility to 2.7 μg/m(3) at 400 m. The N-tolerant X. parietina was not affected and some physiological parameters even showed a higher performance, while the N-sensitive E. prunastri showed a reduced performance with increasing atmospheric concentrations approaching the source. A shift from lichen communities composed by meso-acidophilous species (actual condition) to more nitrophilous communities in the near future, approaching the composting facility is suggested. It is concluded that lichens can provide useful data for decision-makers to establish correct science-based environmentally sustainable waste management policies.
... In total, a much smaller number of species was found on the invasive tree species, and the lichens observed showed a higher nitrogen tolerance. A subsequent study in 2011 (Nascimbene et al. 2012) investigated the influence of the age of the Robinia pseudoacacia phorophyte trees on the lichen occurrence. Even with increasing age of the phorophyte trees, there was no significant increase in lichen diversity. ...
Article
Full-text available
Alien tree species have been introduced to Europe and often used as roadside trees. Currently, preference is given to species that are adapted to urban climate and drier conditions. Native epiphytic lichens are adapted to local tree species; however, little is known whether a shift toward more alien roadside trees would affect the diversity of epiphytic lichens within cities. We considered three genera of roadside trees that are common in Hamburg (Germany) Acer, Tilia, and Quercus, each with a native and an alien species per genus. Species numbers, frequency and diversity of epiphytic lichens were assessed and compared. Tree locations were grouped according to three classes of increasing traffic volume as a proxy for air pollution. Mean bark pH values have been recorded for each tree individual. The species pairs Quercus robur/rubra and Acer platanoides/saccharinum showed significant differences in the diversity and abundance of lichens, with the alien species showing lower values. The species pair Tilia cordata/tomentosa did not show any significant differences. The number of nitrogen-tolerant lichen species differed little among all tree species. Lichen species richness decreased with increasing traffic volume for all tree species pairs, thus demonstrating the inhibiting effect of traffic on the occurrence of lichens. Bark pH differed little between the species pairs yet high traffic volume resulted in an increased bark pH. In conclusion, two out of three alien species had negative effects on lichen diversity. Further tree species should be assessed to better estimate the effect of alien roadside trees on lichen diversity.
... The importance of native forest vs. exotic plantations in relation to biodiversity has been widely discussed not only from a lichenological point of view but also from the perspective of fauna and flora (Nascimbene et al., 2012;Calviño-Cancela et al., 2012;Pedley et al., 2019). When they naturalize and become invasive, the alien trees may have consequences that are still poorly evaluated for epiphytes. ...
Article
Invasive alien species are considered as one of the major threats to global biodiversity. Many widely used forestry trees are potentially invasive, spreading from planting sites into adjoining areas modifying community compo- sition, and altering the native forest. In the Canary Islands, Castanea sativa was established half a millennium ago, in the distributional area of the laurel forest, an endemic forest of the Macaronesia. The impact of invasive species on ecosystem services and more specifically their impact on epiphytic lichens is totally unknown in these archipelagos. The main aim of this work has been to find out if the chestnut tree can host an analogous species composition, richness, and diversity of epiphytic lichens such as those present in the native forest from the Canary Islands. Whilst species richness in both habitats is high, the composition is significantly different. The characteristic species were also different. The chestnut tree hosted rare species linked to ancient and well-preserved forest environments. For this reason, we propose not to completely eradicate the chestnut tree in the Archipelago, but we consider the management and control of its expansion to be essential. Preserving ancient specimens can serve as a lichen biodiversity reservoir.
... For example, R. pseudocacia L. has several effects on the endangered lichen species Lobaria pulmonaria (L.) Hoffm. (loss of diversity, among others) that are also due to climate change [7][8][9]. Thanks to a recent work, several invasive alien species were assessed in Italian regions [10]: in Toscana, Carpobrotus acinaciformis (L.) ...
Article
Full-text available
Knowledge on alien species is needed nowadays to protect natural habitats and prevent ecological damage. The presence of new alien plant species in Italy is increasing every day. Calabria, its southernmost region, is not yet well known with regard to this aspect. Thanks to fieldwork, sampling, and observing many exotic plants in Calabria, here, we report new data on 34 alien taxa. In particular, we found three new taxa for Europe (Cascabela thevetia, Ipomoea setosa subsp. pavonii, and Tecoma stans), three new for Italy (Brugmansia aurea, Narcissus 'Cotinga', and Narcissus 'Erlicheer'), one new one for the Italian Peninsula (Luffa aegyptiaca), and 21 new taxa for Calabria (Allium cepa, Asparagus setaceus, Bassia scoparia, Beta vulgaris subsp. vulgaris, Bidens formosa, Casuarina equisetifolia, Cedrus atlantica, Chlorophytum comosum, Cucurbita maxima subsp. maxima, Dolichandra unguis-cati, Fagopyrum esculentum, Freesia alba, Juglans regia, Kalanchoë delagoënsis, Passiflora caerulea, Portulaca grandiflora, Prunus armeniaca, Prunus dulcis, Solanum tuberosum, Tradescantia sillamontana, and Washingtonia filifera). Furthermore, we provide the first geolocalized record of Araujia sericifera, the confirmation of Oxalis stricta, and propose a change of status for four taxa (Cenchrus setaceus, Salpichroa origanifolia, Sesbania punicea, and Nothoscordum gracile) for Calabria. The updated knowledge on the presence of new alien species in Calabria, in Italy and in Europe could allow for the prevention of other new entries and to eliminate this potential ecological threat to natural habitats.
... When Black Locust invades ecosystems, particularly those with low nutrient soils, enhanced nutrient availability can modify the species composition and reduce biodiversity (e.g. Benesperi et al., 2012;Nascimbene et al., 2012;Lazzaro et al., 2018). The expansion of Black Locust into natural ecosystems has a strong homogenizing effect on both tree and herb layers with progressive decline of conditions and creation of environments that do not support native plant communities (Vítkov� a and Kolbek, 2010;Benesperi et al., 2012;Sitzia et al., 2012). ...
Article
Black Locust (Robinia pseudoacacia L.) is a woody legume with a worldwide distribution. Its ecological and economical importance is largely due to fast growth and dinitrogen (N2)-fixation ability with rhizobia. These features make Black Locust suitable as a model species for other woody legumes as well. However, its symbiotic association with mycorrhizal fungi has not gained much attention. The small body of literature published indicates that this mycorrhizal association interacts with symbiotic N2-fixation, greatly enhancing the ecological and physiological performance of Black Locust by improving its rate of growth, nutrition status and resistance to stress conditions, such as drought and salt and heavy metal accumulation. Here we summarize the current knowledge on the benefits of the association of Black Locust with arbuscular mycorrhizal fungi with the aim of providing future research directions on how this symbiotic partnership is involved in a tripartite symbiotic association including rhizobia. This association is of particular importance considering both the invasive nature of Black Locust, its economic and cultural importance and its use in restoration of degraded or contaminated landscapes.
... In invaded areas, Robinia trees are mixed with, or even have completely substituted, native tree species. Wildlife communities found in Robinia woodlands are usually poorer and less abundant compared to the ones found in native forests, even though not all organisms seem to obviously prefer the second over the first (Remeš, 2003;Nascimbene et al., 2012;Hanzelka and Reif, 2015;Kroftová and Reif, 2017). ...
Article
In Europe land use change has produced loss and fragmentation of the original forest habitat. On the other hand, the area covered by tree plantations and altered stands dominated by exotic tree species is increasing. Forest specialist birds are considered to be among the best candidates to assess the consequences of this transformation on wildlife. Here we investigate the link between the abundances of three forest specialist bird species (the Eurasian Nuthatch Sitta europaea, the Marsh Tit Poecile palustris and the Lesser Spotted Woodpecker Dryobates minor) and the woodland habitats of a highly modified landscape located in north-western Italy. In the area, the cover of anthropogenic woodland habitats, such as poplar plantations and Black Locust (Robinia pseudoacia) stands, exceeds that of native oak and riparian forests. During breeding season, birds were counted for three times along 105 transects of 300 m each, scattered in all the wooded contexts of the study area. Using n-mixture models, we investigated the effect of the amount and configuration of woodland habitats on the abundances of each species. First we selected for each variable the strongest scale of effect, ranging from 0.1 to 4 km. Then we built a full model including all variables at selected scales, accounting for correlation among variables and possible interactions. Forest specialists’ abundances were affected by the composition of the entire woodland mosaic, not of native forests only. A high cover of nonnative woodlands in the landscape showed a null or positive effect on the species, if combined with a high cover of native forests. However, at a local scale and when dominating in the landscape, nonnative woodlands had mostly a detrimental effect. Alongside with the protection of remnant native forests, it should be contemplated the retention of nonnative woodland habitats when these contribute to enhance the heterogeneity of the landscape.
... The effects of black locust on plant communities have been demonstrated by focusing on individual species. Compared to sites colonised by native trees, those colonised by black locust differ in plant 18,19 , bird 20 , lichen 21 and soil biotic 17 communities. Differences vary with stand age, landscape composition and management 22 . ...
Article
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The abandonment of agricultural use is a common driver of spontaneous reforestation by alien trees. The N-fixing black locust (Robinia pseudoacacia L.) is a major alien invader of old fields in Europe. Here we show that canopy dominance by this tree may filter the frequency distribution of plant functional traits in the understory of secondary woodlands. Higher soil C/N ratio and available P are associated with black locust stands, while higher soil phenols associate with native tree stands. These environmental effects result in differences in understory flowering periods, reproduction types and life forms. Our findings emphasize the effect of a major alien tree on functional plant trait composition in the early stages of spontaneous reforestation of abandoned lands, implying the development of a novel forest ecosystem on a large geographical scale.
... At the present time, under steppe conditions almost everywhere a significant expansion of the distribution of R. pseudoacacia is observed; this is related to its growth-inhibiting role in respect to other tree species, such as the oak and ash (Riabchenko, 2012). Invasion of R. pseudoacacia into native oak forests can lead to significant changes in forest-site conditions (Nascimbene et al., 2012). At the same time, R. pseudoacacia often compares poorly in moistening to steppe herbaceous native species. ...
Article
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This article proposes a completely new method of resolving the pressing global environmental problem of assessing the capacity of invasive organisms to adapt to new environmental conditions. A new three-step approach to the evaluation of vital and ecological functions of invasive species is recommended. In addition to classic species and population surveys, it was proposed to apply a stress-resistance biochemical assessment of invasive species. Stress resistance can be regarded as the main response of living organisms to changes in continuous environmental components. The obtained results will provide an opportunity to give a qualitative prognisis of what adaptive capacity an invasive species has,what precise ecological functions and for what time period it can perform in a new ecosystem.
... However, our results did not support the hypothesis that differences in the climatic niche of the three species could have determined distinct distributional patterns in Italy. This outcome could reflect the effect of additional environmental drivers, not considered in this study, that act at the local scale, such in the case of land-use intensity, forest structure, topography, and vegetation type (Nascimbene et al., 2012(Nascimbene et al., , 2013a. This hypothesis is consistent with recent findings (Nascimbene et al., 2013b), stressing that forest structure and local habitat conditions are the main drivers of species turnover in Lobaria pulmonaria communities. ...
Article
Similarly to other Mediterranean regions, Italy is expected to experience dramatic climatic changes in the coming decades. Do to their poikilohydric nature, lichens are among the most sensitive organisms to climate change and species requiring temperate-humid conditions may rapidly decline in Italy, such in the case of the epiphytic Lobaria species that are confined to humid forests. Our study, based on ecological niche modelling of occurrence data of three Lobaria species, revealed that in the next decades climate change will impact their distribution range across Italy, predicting a steep gradient of increasing range loss across time slices. Lobaria species are therefore facing a high extinction risk associated with reduction of their range. The current patterns indicate that only L. pulmonaria still has a continuous distribution across Italy, with potential contact between Apennine and Alpine populations. This situation is consistent with the wider climatic niche of this species, still offering a major oppor- tunity for its successful long-term conservation. Results (a) support the inclusion of the three Lobaria species in European conservation policies, such as the Habitat Directive, and (b) warn against an over-estimation of the in- dicator power of single flagship species to establish conservation priorities for lichens, indicating that even li- chens with peculiar and similar climatic envelopes may fail to co-occur within a given forest stand. A multiple indicator approach could provide more useful tools for a community-based conservation strategy for epiphytes.
... Already two years after invasion of a sandy grassland in Berlin by R. pseudoacacia the species composition had completely changed and this was the case not just for plants but also for spider and beetle species (Kowarik 2003). The diversity of epiphytic lichen biota in mature R. pseudoacacia forests was reduced in comparison to native woodlands that were replaced by the species in Italy (Nascimbene et al. 2012). ...
... This species is recognised as a global invader and is one of the most problematic alien plants in Europe (Kleinbauer et al. 2010;Celesti-Grapow et al. 2009). Previous studies have shown that in Tuscany, the invasion of this species leads to the replacement both of native vascular plants and of epiphyte lichen communities by homogeneous ones with low-diversity Nascimbene et al. 2012). This species was also detected sporadically in the other habitats, with the exception of marshland. ...
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Riparian ecosystems host an high level of biodiversity but anthropic activities have deeply altered their naturalness and functionality. The present study was carried out in a protected area along a recently regulated tract of the upper River Tiber (Tuscany, central Italy). The study’s aim is to explore different components of plant diversity (species richness, species composition, β-diversity) in the riparian habitats to determine the most relevant conservation issues. Twelve transects were allocated along the riparian zone and a stratified random sampling was performed on the habitat detected along the transects with 184 plots of 1 x 1 m. Species richness was analysed by the use of set of species-richness estimators. The different patterns of plant diversity were analysed by NMDS, Indicator Species Analysis and SDR with symplex analysis. Five habitat types were detected in the study area. Three well-represented habitats (riparian woodlands, shrublands and dry bars) showed a higher number of species; flooded banks and marshlands were much less common and were also less species rich. Species composition and indicator species analysis showed however that marshlands were the richest in taxa having high conservation value and in indicator species. The habitats differed greatly in species composition; β-diversity analysis showed a low number of shared species between the habitats. High values of species replacement and low similarity values were recorded between the plots within the habitats. The study shows some differences between quantitative and qualitative patterns of biodiversity in the study area. The results suggest that to maintain habitat species diversity, the best conservation strategy for the study area is to protect as large an area as possible Keywords: conservation; β-diversity; riparian plants; species composition; species richness
... The black locust (Robinia pseudoacacia) is an invasive tree species having serious impacts on native species and ecosystems (Dzwonko and Loster 1997;Rice et al. 2004;Nascimbene et al. 2012;De Marco et al. 2013). In central Europe, the black locust was planted in the seventeenth century on dry rocky slopes with shallow soil (Hejný and Slavík 1997). ...
Article
Biological invasions are among the most important threats to global biodiversity. However, bird species differ in their ability to resist the invasions, and it is thus important to investigate which species’ traits account for their sensitivity to the invasions’ consequences. Here we focused on predictors of such sensitivity by using central European birds in oak forests invaded by the exotic black locust (Robinia pseudoacacia). We performed a detailed mapping of bird occurrence on plots located in the native oak stands and the invaded stands, respectively, controlling for stands’ age. Using multivariate analysis, we quantified bird species’ reliance on the native versus invaded forest stands. In the next step, we tested the hypotheses explaining species’ position along this gradient. We predicted that the species more closely associated with the invaded forest stands will be (1) habitat generalists and (2) species with fast life history strategies. The phylogenetic generalized least squares analysis showed that only the first prediction was supported. Moreover, species’ habitat specialization significantly affected differences in species’ abundance between the invaded and native forests: habitat generalists were more abundant in the black locust stands than in the oak stands, which was not the case of habitat specialists. Our study implies that the spread of invasive plants may contribute to the frequently reported replacement of specialist species by habitat generalists in local bird communities.
... In this perspective, black locust invasion has both direct and indirect effects on biodiversity, respectively changing tree forest and epiphytic community composition. The change of substratum and differences in forest management between native and black locust forests are invoked as potential drivers of the observed shifts in lichen composition which are mainly related to the establishment of highly competitive, nitrogen-tolerant and light-demanding species (Nascimbene et al., 2012). The invasiveness of these lichens in disturbed habitats (Benesperi et al., 2013;Giordani et al., 2010) has many similarities with that of several alien species that behave as biotic homogenizers. ...
Article
We compared epiphytic lichen communities of native broadleaved and secondary black locust (Robinia pseudoacacia) forests to detect possible differences in community structure that could be indicative of biological homogenization enhanced by the replacement of native by black locust forests. The study was carried out in two areas of Italy with different bioclimatic conditions using a balanced stratified random sampling. Results reveal a different pattern of community structure between native and black locust forests across the two regions that may reflect a process of biological homogenization. In particular, lichen communities of black locust forests share several species between the two study regions. This pattern of floristic homogenization parallels with a functional homogenization related to the spread of highly competitive species. This research provides early evidence that the decrease of native forests associated with the spread of black locust is a mechanism triggering biological homogenization of the epiphytic lichen biota.
... The shift in species composition found in our stands appears to be mainly driven by the higher contribution of the guild of nitrophilous plants in terms of both relative species number and abundance in the invaded stands. This is a typical scenario for a "transformer", as have been already highlighted for R. pseudoacacia for both vascular plant and epiphytic lichen communities (Nascimbene et al., 2012). The linkage between nitrophilous species and soil N content is also reflected in the way they change across the invasion status degree. ...
... Most Italian lichenologists are currently focusing on ecological topics with applications, such as the evaluation of the role of lichens in biodeterioration of stone artefacts of artistic/historic value (Piervittori, Favero-Longo, and Gazzano 2009), the evaluation of the effects of air pollution (Nimis, Scheidegger, and Wolseley 2002), and forest management (e.g. Matteucci, Isocrono, and Piervittori 2010;Nascimbene, Marini and Nimis 2010;Nascimbene, Nimis, and Benesperi 2012). However, most of these studies assess the response of lichen communities in terms of species richness and composition and may therefore contribute to further improve lichen floristics in Italy. ...
Article
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Western Italian Alps (namely Piedmont and the Aosta Valley) are among the lichenologically best known regions of Italy with c.1200 species listed. However, despite the long temporal continuity of lichen studies, information is still geographically uneven and data on the occurrence and distribution of many species are missing. An opportunity to fill this gap is currently provided by ecological and applied studies that assess the response of lichen communities to environmental factors in terms of species richness and composition. This study reports species that are new or interesting records for the western Italian Alps or noteworthy mainly because of their conservation status provided by ecological and applied studies in Aosta Valley and Piedmont and by some recent floristic surveys. A list of 51 records referring to 47 species is reported and discussed; 20 species are new to the Aosta Valley, 17 are new to Piedmont and 11 species are reported for the first time in the Western Italian Alps, being new for both regions. More than 25% of the records derive from stonework biodeterioration studies providing noteworthy data due to substrata analysed. About 35% of records derive from both air pollution monitoring studies and research on lichen conservation in relation to forest management. Biomonitoring studies are based on robust sampling design that allows data to be compared across regions and time series, improving the information associated with floristic data. Research on epiphytic lichens in Italian forests, rapidly increasing in Italy in the last years, has contributed significant advances in lichen floristics in Italy and in modelling environmental factors that are relevant for lichen ecology and conservation.
... Invasive woody plants, which replace native forest vegetation, may impact the forest biota acting as habitat 'transformers' (Richardson and Rejmánek 2011). For example, they may impact both epiphytes and understory vegetation by altering substrate and stand conditions related to their management (Dzwonko and Loster 1997;Le Maitre et al. 2011;Nascimbene et al. 2012). ...
... Most Italian lichenologists are currently focusing on ecological topics with applications, such as the evaluation of the role of lichens in biodeterioration of stone artefacts of artistic/historic value (Piervittori, Favero-Longo, and Gazzano 2009), the evaluation of the effects of air pollution (Nimis, Scheidegger, and Wolseley 2002), and forest management (e.g. Matteucci, Isocrono, and Piervittori 2010;Nascimbene, Marini and Nimis 2010;Nascimbene, Nimis, and Benesperi 2012). However, most of these studies assess the response of lichen communities in terms of species richness and composition and may therefore contribute to further improve lichen floristics in Italy. ...
Article
Western Italian Alps (namely Piedmont and the Aosta Valley) are among the lichenologically best known regions of Italy with c.1200 species listed. However, despite the long temporal continuity of lichen studies, information is still geographically uneven and data on the occurrence and distribution of many species are missing. An opportunity to fill this gap is currently provided by ecological and applied studies that assess the response of lichen communities to environmental factors in terms of species richness and composition. This study reports species that are new or interesting records for the western Italian Alps or noteworthy mainly because of their conservation status provided by ecological and applied studies in Aosta Valley and Piedmont and by some recent floristic surveys. A list of 51 records referring to 47 species is reported and discussed; 20 species are new to the Aosta Valley, 17 are new to Piedmont and 11 species are reported for the first time in the Western Italian Alps, being new for both regions. More than 25% of the records derive from stonework biodeterioration studies providing noteworthy data due to substrata analysed. About 35% of records derive from both air pollution monitoring studies and research on lichen conservation in relation to forest management. Biomonitoring studies are based on robust sampling design that allows data to be compared across regions and time series, improving the information associated with floristic data. Research on epiphytic lichens in Italian forests, rapidly increasing in Italy in the last years, has contributed significant advances in lichen floristics in Italy and in modelling environmental factors that are relevant for lichen ecology and conservation.
... Shifts in the composition of lichen communities have been related to different drivers, including pollution, climatic change and human management (Ellis and Coppins, 2010), being of interest for environmental monitoring and diversity conservation. Colonization-extinction and recolonization patterns have been examined following changes in air quality (Nimis et al., 2002) or landscape variations, as glacial retreats (Raab et al., 2012) or forest disturbances (Nascimbene et al., 2012), and simulating climate change (e.g. Maphangwa et al., 2012). ...
Article
Fungal particulates are a dominant component of the bioaerosol, but aerobiological studies traditionally focused on a limited set of fungi having relevance as allergens or plant pathogens. This study first analyzes the occurrence of lichen meiospores in the mycoaerosol, quantitatively evaluating in the atmosphere of an alpine environment the occurrence of polar diblastic spores, unequivocally attributable to the lichen family Teloschistaceae. The analysis of air-samples collected one week per month for one year with a Hirst-type sampler displayed a low percentage occurrence of polar-diblastic spores (<0.1%) with respect to the whole mycoaerosol, dominated by Cladosporium. Spearman's correlation tests on aerobiological and climatic data highlighted a strong relationship between the detection of Teloschistaceae spores and rainfall events, excluding seasonal patterns or daily rhythms of dispersion. The fact that all the air-sampled spores were attributable to the species of Teloschistaceae occurring in the site, together with laboratory observations of predominant short range dispersal patterns for polar diblastic and other lichen spores, indicated that sexual reproduction is mostly involved in the local expansion of colonization, dispersal from a long distance appearing a less probable phenomenon. These findings indicated that responses of lichen communities to climate factors, usually related to physiological processes, also depend on their influence on meiospore dispersal dynamics. Spatial limitations in dispersal, however, have to be taken into account in evaluating lichen distributional shifts as indicators of environmental changes.
... Pine plantations, although more shady than eucalypt plantations, have also an open canopy structure and their leaf shape (needles) also favors higher light penetration and more aridity as compared to oak forests (Barbier et al., 2008), making them less suitable for lichens requiring high humidity. Käffer et al. (2010) found also a relatively high frequency of light demanding lichen species in pine and eucalypt plantations (see also Nascimbene et al., 2012 for similar results with Robinia pseudoacacia). Canopy structure was also a key determinant of understory vascular plant vegetation, with the most shade-tolerant forests specialists (which included the species with most severe rarity) occurring in native forests but being absent from pine and eucalypt plantations (Calviño-Cancela et al., 2012; a study carried out in the same sites). ...
... Invasive woody plants, which replace native forest vegetation, may impact the forest biota acting as habitat 'transformers' (Richardson and Rejmánek 2011). For example, they may impact both epiphytes and understory vegetation by altering substrate and stand conditions related to their management (Dzwonko and Loster 1997; Le Maitre et al. 2011; Nascimbene et al. 2012). Black-locust is native to the south-eastern United States and it is recognized as one of the most problematic invaders in Europe (Kleinbauer et al. 2010), including Italy (CelestiGrapow et al. 2009). ...
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The effects of black-locust invasion on plant forest diversity are still poorly investigated. Vascular plants are likely to be influenced by increasing nutrient availability associated with the nitrogen-fixing activity of black-locust, whereas it is not clear if, along with stand aging, black-locust formations regain forest species. The main aim of the present study was to test whether the increase of black-locust stand age promoted a plant variation in mature stands leading to assemblages similar to those of native forests. Therefore, plant richness and composition of stands dominated by native trees were compared with pure black-locust stands of different successional stages. Our study confirmed that the replacement of native forests by pure black-locust stands causes both plant richness loss and shifts in species composition. In black-locust stands plant communities are dominated by nitrophilous species and lack many of the oligothrophic and acidophilus species typical of native forests. Plant communities of native forests are more diverse with respect to pure black-locust stands, suggesting that black-locust invasion also causes a homogenization of the plant forest biota. We did not detect differences across the successional gradient of black-locust stands, and mature stands do not recover the diversity of plant species which are lost by the replacement of the native forests by black-locust. Accordingly some efforts in reducing the negative impacts of black-locust invasion on plant forest biota should be focused at least in those areas where conservation is among management priorities, such in the case of habitats included in the Habitat Directive (92/43 ECE).
Article
Invasive alien plants are a major threat to biodiversity and they contribute to the unfavourable conservation status of habitats of interest to the European Community. In order to favour implementation of European Union Regulation no. 1143/2014 on invasive alien species, the Italian Society of Vegetation Science carried out a large survey led by a task force of 49 contributors with expertise in vegetation across all the Italian administrative regions. The survey summed up the knowledge on impact mechanisms of invasive alien plants in Italy and their outcomes on plant communities and the EU habitats of Community Interest, in accordance with Directive no. 92/43/EEC. The survey covered 241 alien plant species reported as having deleterious ecological impacts. The data collected illustrate the current state of the art, highlight the main gaps in knowledge, and suggest topics to be further investigated. In particular, the survey underlined competition as being the main mechanism of ecological impact on plant communities and Natura 2000 habitats. Of the 241 species, only Ailanthus altissima was found to exert an ecological impact on plant communities and Natura 2000 habitats in all Italian regions; while a further 20 species impact up to ten out of the 20 Italian administrative regions. Our data indicate that 84 out of 132 Natura 2000 Habitats (64%) are subjected to some degree of impact by invasive alien plants. Freshwater habitats and natural and semi-natural grassland formations were impacted by the highest number of alien species, followed by coastal sand dunes and inland dunes, and forests. Although not exhaustive, this research is the first example of nationwide evaluation of the ecological impacts of invasive alien plants on plant communities and Natura 2000 Habitats.
Article
Gyalectidium minus Sérus., new to oceanic western Europe in the first reported foliicolous lichen community of continental Portugal - Volume 52 Issue 3 - William B. Sanders, Esteve Llop
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Paper presents a systematic global review of Acer negundo, Fraxinus pennsylvanica, Ailanthus altissima, Robinia pseudoacacia invasions focusing on the Scopus and Web of Science databases. We examined the data on papers, study areas, habitat studied, topic discussed. We hypothesized that these species were studied evenly throughout their invaded ranges and, as such, indexed by international databases. We asked whether four selected species are presented evenly in publications related to their invaded ranges, and whether both selected databases cover well a content of these papers. We found 48 papers for A. negundo, 14 – for F. pennsylvanica, 83 – for A. altissima, 96 – for R. pseudoacacia. A high percentage of the studies were conducted in Central Europe and USA (for A. altissima), while Eastern Europe, Russia, Western United States were poorly represented. Most studies were conducted in forests, and focused on impacts or distribution of aliens in invaded range, and their control and management. We encountered habitat types invaded by trees, factors influencing tree invasions, consequences of invaders’ impact on ecosystems, counteracting measures. We concluded that the use only Web of Science and Scopus is not sufficient to obtain the complete data about the invasion biology.
Chapter
In this chapter, the main ecological factors that characterize the epiphytic environment and which determine the composition of epiphytic communities have been described. In particular, emphasis has been made to focus on epiphytic lichens which, due to their ecophysiological characteristics, represent a set of highly specialized organisms that live in a delicate balance in this habitat. The main threats that affect their survival have been analysed along with the conservation actions that have been undertaken to ensure the maintenance of the populations of the most endangered species. Furthermore, some good practices are suggested that can guarantee greater success of future protection actions.
Article
Invasions of ecosystems by alien species are one of the major threats to biodiversity. Among alien plant species, members of the family Fabaceae s.l. represent some of the most dangerous and well known global invaders. In Mediterranean ecosystems, many Australian acacias have been found to establish and rapidly spread, often determining severe impacts on understorey vegetation. In the present work, we report the case study of Acacia pycnantha invasion in a typical Mediterranean matorral (Elba Island, central Mediterranean Sea, Italy). We conducted a survey of understorey plant communities across an invasion gradient from non-invaded to transitional and invaded areas, aiming to quantify the impacts on the understorey assemblage and to investigate the ecological processes involved in the changes in species composition. The understorey plant community was highly affected starting from the intermediate stage of invasion. Species richness, diversity and total cover were all lower in invaded than in non-invaded plots, with a transition generally in the middle. In addition, plant community composition severely changed along the invasion gradient. The species set we recorded showed a nested structure, with the composition of species in the invaded plots representing a subset of the others. According to our findings, A. pycnantha exerted detrimental impacts on the native vegetation, mainly causing severe species loss in the understorey assemblage and impoverishment of the invaded ecosystems.
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There is little available information on lichen diversity and air quality in forests in South Korea. To address this, the present study aims to correlate corticolous lichen diversity with air quality in selected forests in South Korea. Two sites located on Jeju Island and one site located at Mt. Hambaek, Kangwon Province were selected for this study. Twenty trees representing two species (Quercus sp. and Pinus japonica) were chosen at each site. The coverage and frequency of corticolous lichens found on the selected trees were recorded by using 2500 cm2 grids. Ambient SO2, NO2, and O3 levels at each site were determined using Ogawa™ passive samplers having filter pads coated with absorbing reagents. Lichen diversity data collected on selected trees were used to formulate the index of atmospheric purity (IAP). A total of 65 lichen species were found. A negative correlation was observed between lichen diversity expressed as IAP and the concentrations of SO2, NO2, and O3 levels. The results revealed that corticolous lichens could be used as indicators to monitor the air quality of forests in South Korea on a large scale.
Article
Short rotation woody bioenergy crops (SRWC) could contribute a substantial portion of the biomass required to meet federal mandates and offset carbon emissions. One SRWC with strong bioenergy potential is black locust (Robinia pseudoacacia L.), planted extensively for wood and energy applications globally, but under-studied in its native US. This member of the Fabaceae family can fix nitrogen, tolerate stress, and sequester carbon while generating biomass yields up to 14 Mg ha-1 yr-1. This article offers a comprehensive state-of-the-art review of production practices, biomass and energy yield estimates, environmental risks and benefits, and economic considerations for this promising feedstock.
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The epiphytic lichen flora of 25 European ICP-IM monitoring sites, all situated in areas remote from air pollution sources, was statistically related to measured levels of SO2 in air, NH4+, NO3− and SO42− in precipitation, annual bulk precipitation, and annual average temperature. Significant regression models were calculated for eleven acidophytic species. Several species show a strong negative correlation with nitrogen compounds. At concentrations as low as 0·3 mg N l−1 in precipitation, a decrease of the probability of occurrence is observed for Bryoria capillaris, B. fuscescens, Cetraria pinastri, Imshaugia aleurites and Usnea hirta. The observed pattern of correlations strongly suggests a key role of NH4+ in determining the species occurrence, but an additional role of NO3− cannot be ruled out. Some species show a distinct response to current levels of SO2 as well. It may be concluded that long distance nitrogen air pollution has strong influence on the occurrence of acidophytic lichen species.
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1 fig. [Correction of figure from article in Lichenologist 35(4): 347-359 (2003).]
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In the last decades, several methods were proposed for assessing environmental quality — mainly air pollution — on the basis of lichen data (see chapter 4, this volume). At the end of the 80s the predictivity of 20 different methods with respect to instrumental pollution data was tested in Switzerland using multiple regression [1, 5]. The highest correlation was found with the sum of frequencies of lichen species within a sampling grid of 10 units positioned on the trunks of free-standing trees. This method was immediately and widely adopted in several other countries, esp. Italy and Germany, with some modifications, chiefly concerning the size of the sampling grid. Since 1987, hundreds of studies were carried out with this approach, which led to its standardization in the form of guidelines both in Germany [13], and in Italy [7].
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Chemical properties of black locust wood and bark from Greece, Bulgaria and Hungary (clones NY, U and J) were investigated. Disks at breast height were taken from 25 black locust trees (five trees per origin and clone) and were divided into separate biomass components (juvenile heartwood, mature heartwood, sapwood and bark). Hot water soluble (HWSE) and dichloromethane soluble extractives (DSE), acidity (pH), buffering capacity, ash content and inorganic elements were determined according to standard laboratory techniques. Bark had the highest extractive content for both HWSE ( 9.25-13.49%) and DSE (3.09-4.03%). Differences of extractive contents in wood were found to exist between trees of different origin and between the three clones and ranged in heartwood between 5.04-10.10% for HWSE and 0.53-1.83% for DSE and in sapwood between 3.33-6.76% for HWSE and 0.48-1.47% for DSE. The higher values of pH occurred in sapwood (4.92-5.35), while the differences between bark (4.44-5.12) and heartwood (4.35-4.92) were small. Acid (ABC) and base (BBC) buffering capacities from the initial to pH 10 for ABC and to pH 3 for BBC were greater in bark (ABC 0.0172-0.0219 ml/ml and BBC 0.0079-0.0141 ml/ml) than in the other wood components (for heartwood ABC 0.0069-0.0159 ml/ml and BBC 0.0022-0.0096 ml/ml and for sapwood ABC 0.00330.0066 ml/ml and BBC 0.00330.0049 ml/ml). The total ash content was greater in bark (7.24-8.56%) than in other biomass components (for heartwood 0.34-0.89% and for sapwood 0.72-1.24%). The content of the main inorganic elements (Ca, K, Mg, Na, P) were also found to be much higher in bark while sapwood values were greater than heartwood.
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In western North America, quaking aspen (Populus tremuloides) is the most common hardwood in montane landscapes. Fire suppression, grazing and wildlife management practices, and climate patterns of the past century are all potential threats to aspen coverage in this region. If aspen-dependent species are losing habitat, this raises concerns about their long-term viability. Though lichens have a rich history as air pollution indicators, we believe that they may also be useful as a metric of community diversity associated with habitat change. We established 47 plots in the Bear River Range of northern Utah and southern Idaho to evaluate the effects of forest succession on epiphytic macrolichen communities. Plots were located in a narrow elevational belt (2134–2438 m) to minimize the known covariant effects of elevation and moisture on lichen communities. Results show increasing total lichen diversity and a decrease in aspen-dependent species as aspen forests succeed to conifer cover types. The interactive roles of stand aspect, basal area and cover of dominant trees, stand age, aspen bark scars, and recent tree damage were examined as related to these trends. We developed an aspen index score based on lichens showing an affinity for aspen habitat (Phaeophyscia nigricans, Physcia tenella, Xanthomendoza fulva, Xanthomendoza galericulata) and found a significant negative relationship between the index and successional progression. Indicator species analysis showed the importance of all stages of aspen-conifer succession for lichen community diversity and highlighted the decline of aspen-dependent species with advancing succession. We present a landscape-level community analysis of lichens in the context of a conceptual model for aspen succession for the southern Rocky Mountains. We conclude that while total number of lichen species increases with succession, aspen-dependent species cover and richness will decline. In this way, epiphytic lichens communities may constitute an effective indicator of community-level diversity in for aspen-dependent species at-large.
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Birds can serve as useful model organisms to investigate community level consequences of forestry practices. In this study we investigated the relationships between wintering bird communities and habitat and landscape characteristics of lowland managed forests in Northern Italy. This area is characterized by the spread of the black locust, an alien species that has been favored by forestry practices at the expense of natural oak forests. Birds were censused in winter by point counts in randomly selected plots of 50 m radius. We first addressed bird community–habitat relationships by means of habitat structure measurements, then we investigated bird community–landscape relationships by using GIS techniques. We used generalized linear models (GLM) to test for the effects of habitat and landscape variables on bird community parameters (namely bird species richness, diversity and abundance). Bird community parameters were influenced by oak biomass and tree age, and by oak area and core area, while the other forest habitat types showed less influence. In forest management terms, the main conclusion is that the retention of native oaks is the keyfactor for the conservation of winter bird diversity in local deciduous woods. At the habitat level black locust harvesting may be tolerated, provided that old, large, native oaks are retained in all local woodlots to preserve landscape connectivity and foraging resources. At the landscape meso-scale, large native oak patches, should be preserved or, where necessary, restored.
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The alluvial forests of the Ticino valley have been greatly reduced in size and are now represented by only a small number of fragmented remnants. To study the natural development of the black locust, an invasive species, on relatively undisturbed lowland forests, two permanent plots were established in 2005 in the "Siro Negri" Forest Reserve. The black locust became established almost exclusively between 1940 and 1960. The observed dynamic of the black locust in the Reserve was very similar to what has been observed in its native North American range: following the initial colonization, the black locust firmly established itself in the dominant and intermediate layers but did not regenerate. In addition to the absence of a significant younger population, the decline of the black locust is evident in an elevated mortality rate and higher proportion of black locust biomass in the total coarse woody debris (CWD) Our results support the hypothesis that the best strategy to control the spread of black locust is to avoid disturbances that favour black locust colonization, and to wait for natural suppression of the species by other trees. Due to the lack of past reference conditions and the future uncertainties, ongoing monitoring will be needed to fully understand the dynamics of forest ecosystem change in the Reserve.
Article
With a synchronic analysis we studied the main stand parameters of 17 black locust coppices aged between 1–41 years. The homogeneous site conditions of the stands made it possible to study the structure of their dynamics in the context of a time period twice or three times longer than the traditional rotation period. Main dendrometrical and structural parameters of the studied stands are described. In undisturbed conditions, 5–7 years after the coppicing, natural regeneration of other broadleaved species starts to occur in the stands and eventually reaches the robinia crown belt, which begins to reduce its cover.
Article
Lichen and bryophyte communities of spruce and pine plantations in different parts of Britain were surveyed and compared to those of semi-natural pine and oak woodlands. In total, 202 lichen species and 111 bryophytes were recorded. Community composition and species-richness were related to measures of climate, stand structure and deadwood (snags, logs and stumps). Plantations had a less species-rich lichen flora than semi-natural stands related to reduced light availability and lack of old trees. Bryophyte species-richness was similar in plantations and semi-natural stands, and was positively correlated with large diameter (>20 cm), well-decayed logs and stumps. Lichens species-richness was higher on decorticate snags (especially in semi-natural Scots pine stands in the Scottish Highlands). Early successional stands were often the richest for lichens, stumps being important for Calicium and Cladonia species. Three strategies are suggested for enhancing lower plant diversity in planted forests: (1) extending felling rotations; (2) introducing alternative silvicultural systems to clear-felling (e.g. single-tree selection) to foster continuity of woodland conditions and increase deadwood volumes; (3) modifying restocking practices on clear-fells to avoid excessive shading of deadwood.
Article
Early forest regeneration in southern Appalachian hardwood forests is dominated by the woody nitrogen-fixing legume, black locust. Although it grows most prevalently on clear-felled areas, abandoned pasture or disturbed roadsides, it may have historically been an important colonizer of burned sites. It commonly reproduces from seed germination, but sprouting from stumps and roots is its commonest means of regeneration. Early sprout growth is rapid, reaching heights up to 8 m in 3 yr. Except for stands on high-nutrient sites, growth decreases after 10-20 yr. In less vigorous stands, stem mortality may be high due to attacks by locust stem borer Megacyllene robiniae. The high mortality of black locust is an early successional mechanism that releases codominant species such as Liriodendron tulipifera, and creates canopy gaps favourable for growth of longer-lived individuals. Total biomass accretion in 4, 17 and 38-yr-old black locust stands growing on fertile, mesic sites was 33, 174 and 399 t ha-1, respectively, in comparison to 198 t ha-1 for an older, uneven-aged mixed oak forest with a history of disturbance. Biomass accumulation was the predominant fate of fixed N in all 3 stands, with an addition to total soil N apparent only in the 38 yr old stand. Symbiotic N fixation by black locust apparently increased the concentration of NO3 in the soil. Total stand N increased at a net average annual rate of 48, 75 and 33 kg ha-1 yr-1, respectively, for ages 4, 17 and 38. Nodule biomass was 8, 106 and 4 kg ha-1 in the 4, 17 and 38-yr-old stands respectively.-from Authors
Article
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.
Article
In Italy several natural reserves include riparian habitats, whose role in lichen conservation is still poorly known. This work aims at evaluating the importance for lichen conservation of a riparian natural reserve in NE Italy surrounded by a highly disturbed landscape, and at exploring the relations between lichen composition and different forest types. Epiphytic lichens were surveyed by a standard assessment protocol in: (1) alluvial Salix alba forests, (2) Alnus sp.pl. and Populus sp.pl. riparian forests, and (3) lowland Carpinus betulus and Quercus sp.pl. forests. One-way ANOVA was used to test differences between forest types. Species composition was explored by means of Redundancy Analysis. The overall lichen flora is relatively poor and rather homogeneous due to a group of disturbance-tolerant lichens, which are frequent in all forest types. This suggests a strong influence of the landscape context on species richness and composition, independently of the local habitat quality. However, the three forest types have rather different lichen floras, the least interesting for conservation being the riparian Alnus stands, while the alluvial Salix stands host a more sensitive flora and are worthy of lichen conservation. In spite of the disturbance and of its small extension, the reserve is still able to host several rare lichens.
Article
In Italy several natural reserves include riparian habitats, whose role in lichen conservation is still poorly known. This work aims at evaluating the importance for lichen conservation of a riparian natural reserve in NE Italy surrounded by a highly disturbed landscape, and at exploring the relations between lichen composition and different forest types. Epiphytic lichens were surveyed by a standard assessment protocol in: (1) alluvial Salix alba forests, (2) Alnus sp.pl. and Populus sp.pl. riparian forests, and (3) lowland Carpinus betulus and Quercus sp.pl. forests. One-way ANOVA was used to test differences between forest types. Species composition was explored by means of Redundancy Analysis. The overall lichen flora is relatively poor and rather homogeneous due to a group of disturbance-tolerant lichens, which are frequent in all forest types. This suggests a strong influence of the landscape context on species richness and composition, independently of the local habitat quality. However, the three forest types have rather different lichen floras, the least interesting for conservation being the riparian Alnus stands, while the alluvial Salix stands host a more sensitive flora and are worthy of lichen conservation. In spite of the disturbance and of its small extension, the reserve is still able to host several rare lichens.
Article
Aim To quantify the interaction between climate and woodland continuity in determining the bioclimatic response of lichen epiphytes. Location Northern Britain (Scotland). Methods Indicator-species analysis was used to pre-select lichen epiphytes along parallel gradients in climate and the extent of old-growth woodland. Nonparametric multiplicative regression was used to describe in a predictive model the individualistic response of selected species, which were projected based on climate-change scenarios and contrasting patterns of simulated woodland loss or gain. Species with a similar response were grouped using a novel application of cluster analysis to summarize the potentially huge number of projected outcomes. Projected patterns of occurrence under climate-change scenarios were examined for different levels of old-growth woodland extent. Results Forty-two lichen species were statistically significant indicator species in oceanic woodlands, and old-growth indicators under suboptimal climatic conditions. Responses to climate-change scenarios were contrasting, with one group comprising species projected to increase in extent in response to climate warming, and other response groups projected to decrease in occurrence, possibly in response to shifting rainfall patterns. The occurrence of all response groups had a positive relationship with old-growth woodland extent. Main conclusions An ‘oceanic’ biogeographical group of epiphytes identified using the baseline climatic and present-day woodland setting comprised species with a cyanobacterial photobiont or tropical phytogeographical affinities. However, within this group the individual species responses to climate-change scenarios were contrasting. Additionally, group responses may be poorly matched with simple ecological traits. However, the studied interaction between climate and habitat continuity suggests that the impact of climate change might be offset for certain lichen epiphytes by appropriate management of woodland resources, for example, expansion of native woodland around remnant old-growth stands.
Article
Aim Woody plants were not widely considered to be important invasive alien species until fairly recently. Thousands of species of trees and shrubs have, however, been moved around the world. Many species have spread from planting sites, and some are now among the most widespread and damaging of invasive organisms. This article presents a global list of invasive alien trees and shrubs. It discusses taxonomic biases, geographical patterns, modes of dispersal, reasons for introductions and key issues regarding invasions of non‐native woody plants around the world. Location Global. Methods An exhaustive survey was made of regional and national databases and the literature. Correspondence with botanists and ecologists and our own observations in many parts of the world expanded the list. Presence of invasive species was determined for each of 15 broad geographical regions. The main reasons for introduction and dissemination were determined for each species. Results The list comprises 622 species (357 trees, 265 shrubs in 29 plant orders, 78 families, 286 genera). Regions with the largest number of woody invasive alien species are: Australia (183); southern Africa (170); North America (163); Pacific Islands (147); and New Zealand (107). Species introduced for horticulture dominated the list (62% of species: 196 trees and 187 shrubs). The next most important reasons for introduction and dissemination were forestry (13%), food (10%) and agroforestry (7%). Three hundred and twenty‐three species (52%) are currently known to be invasive in only one region, and another 126 (20%) occur in only two regions. Only 38 species (6%) are very widespread (invasive in six or more regions). Over 40% of invasive tree species and over 60% of invasive shrub species are bird dispersed. Main conclusions Only between 0.5% and 0.7% of the world’s tree and shrub species are currently invasive outside their natural range, but woody plant invasions are rapidly increasing in importance around the world. The objectively compiled list of invasive species presented here provides a snapshot of the current dimensions of the phenomenon and will be useful for screening new introductions for invasive potential.
Article
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.
Article
We investigated the influence of the exotic nitrogen-fixing black locust (Robinia pseudoacacia) on nitrogen cycling in a pitch pine (Pinus rigida) −scrub oak (Quercus ilicifolia, Q. prinoides) ecosystem. Within paired pine-oak and adjacent black locust stands that were the result of a 20-35 year-old invasion, we evaluated soil nutrient contents, soil nitrogen transformation rates, and annual litterfall biomass and nitrogen concentrations. In the A horizon, black locust soils had 1.3-3.2 times greater nitrogen concentration relative to soils within pine-oak stands. Black locust soils also had elevated levels of P and Ca, net nitrification rates and total net N-mineralization rates. Net nitrification rates were 25-120 times greater in black locust than in pine-oak stands. Elevated net N-mineralization rates in black locust stands were associated with an abundance of high nitrogen, low lignin leaf litter, with 86 kg N ha–1 yr–1 in leaf litter returned compared with 19 kg N ha–1 yr–1 in pine-oak stands. This difference resulted from a two-fold greater litterfall mass combined with increased litter nitrogen concentration in black locust stands (1.1% and 2.6% N for scrub oak and black locust litter, respectively). Thus, black locust supplements soil nitrogen pools, increases nitrogen return in litterfall, and enhances soil nitrogen mineralization rates when it invades nutrient poor, pine-oak ecosystems.
Article
This paper provides a quantitative review of the consequences of disturbance on epiphytic lichens in boreal and near boreal forests, focusing on disturbance effects on lichen persistence, growth, and colonization, and on the development (recovery rates) of lichen diversity over time. Lichen persistence, growth, and colonization were examined by reviewing studies on e.g. edge-effects, lichen transplants, and logging experiments. Recovery rates were examined by reviewing studies on relationships between lichen diversity and stand age. The results from the reviewed studies were analysed by various meta-analysis methods. The review showed e.g. overall negative effects of disturbance on lichen persistence, but that persistence depend on the magnitude of the disturbance (e.g. forest edge orientation and clearcut size). However, many lichens seem to persist disturbance, and growth rates were as good in disturbed as in intact forest. The review also showed that lichen populations may need long time to recover, but that species richness does not necessarily increase over time. However, disturbance origin (logging or natural disturbance) is important to explain lichen diversity but is often confounded with stand age. The results are promising for the potential to restore and maintain lichen diversity by forest management methods based on natural disturbance regimes. Further research is needed to e.g. separate the effects of time since disturbance and disturbance type, to examine edge-effects under varying edge conditions, and to examine the influence of landscape context on stand level lichen diversity.
Article
The effects of forest continuity at local scale for red-listed and indicator species of epiphytic lichens and bryophytes were investigated in 150 Fagus sylvatica stands in southern Sweden. Stands having forest continuity (n = 106) had continuous forest cover more than 350 years, whereas stands lacking continuity (n = 44) had forest cover less than 160 years. Forest continuity was identified by comparing a sequence of historical maps with a modern survey of beech forests. In the field woody beech substrates were searched for the epiphytes of interest. A number of environmental and spatial variables were inventoried and compiled for each stand. In all 64 species (51 lichens, 13 bryophytes) were found in the stands having continuity, and 21 (14 lichens, 7 bryophytes) in the stands lacking continuity. Controlling for the different number of surveyed stands, stands having continuity had significantly more species of lichens, but not of bryophytes. In the stands lacking continuity we did not find lichens associated with the very late succession stage. The quantity of substrates, stand age and forest continuity were the three most important factors explaining species richness as well as composition of studied epiphytes. The effect of continuity was probably due to a combination of a higher substrate quality, mainly old beeches, and a longer time available for colonization. Also, we found strong positive correlations between number of indicator and red-listed epiphyte species. In short-term conservation old stands having continuity, containing suitable substrates and indicator species are target areas.
Article
Forest age is one of the most simple but ecologically effective key values that may be controlled by forest management. Young and mature but managed forests differ significantly from old-growth forests in species composition, structure and socio-ecological function. Human land-use has already caused the loss or dramatic reduction in occurrence of some entire species assemblages, especially of logging-sensitive species, in Central European forests. These general statements also apply to beech forests, beech (Fagus sylvatica) being the naturally dominating tree species in Central Europe. Based on data for breeding birds (from 258 sampling plots in a sub-montane and 228 plots in a montane area), molluscs (36 plots in the sub-montane and 79 plots in the montane area) and lichens (84 plots in the montane forest), this paper aims at identifying significant forest age threshold ranges for the occurrence of these old-growth sensitive taxa. The sampling plots in the sub-montane zone (420–520 m a.s.l.) are in beech-oak forests, plots in the montane zone (650–1150 m a.s.l.) are in beech-spruce-fir forests. Stand ages in both areas range up to around 350–400 years. Threshold values for the total number of species related to stand age were calculated by recursive partitioning.
Article
We studied the species composition of epiphytic macrolichens in 18 aspen (Populus tremula) stands, in the boreal forest in Sweden. In total, 51 macrolichens were found, 15 of which were aspen specialists. Quantitative features, e.g. signal species, showed a stronger correlation than quantitative features, e.g. total number of species, with increasing stand age. Aspen specialists showed a significant difference in dispersal mode, early colonizers are mainly sexually dispersed and late colonizers are mainly asexually dispersed. Cyanolichens, were confined to late-successional stands, and did not occur in adjacent younger stands. It is concluded that late-successional aspen stands in the forest must be conserved to function as core habitats for dispersal to young stands. Thus, such young stands have to be continuously created in order to retain the unique lichen flora associated with aspen stands in the forest landscape.
Article
Lichens are composite organisms consisting of a symbiotic association of a fungus with a photosynthetic partner. Although the photobiont type is a key life-history trait, tests of the potential differential role of the main photobiont types in shaping large-scale patterns of lichen species richness are still absent. The aim of the study was to test the influences of forest structure and climate on epiphytic lichen species richness across Italy and to see whether these relationships change for groups of species sharing different photobiont types. Regional species richness of epiphytic lichens divided into three main photobiont types (i.e. chlorococcoid green algae, cyanobacteria, and Trentepohlia algae) was retrieved for each of the 20 administrative regions. Multiple linear regression was used to quantify the effect of climate and forest structure, and their potential interaction, on the regional species richness for the three photobiont types, accounting also for the effect of regional area. Regional species richness was associated with both climate and forest structure variables but the relationships with both factors were largely photobiont dependent. Regional area and precipitation were the only predictors included in all the models, confirming the strong dependence of lichens on atmospheric water supply, irrespective of the photobiont type. Number of species with chlorococcoid green algae were further positively associated with cover of high forest, whilst lichens with Trentepohlia were further enhanced by warm temperatures. Cyanolichen species richness was only related to area and precipitation. Our study shed light on the relative importance of climate and forest structure on lichen species richness patterns at the macroscale, showing a differential response of the photobiont types to various environmental determinants. This differential response suggested that the current and future impacts of global change on lichens cannot be generalized and that species richness response will be likely dependent on the photobiont type.
Article
In the last two centuries, native European oak forests have undergone a dramatic decline related to increasing human pressure for agriculture and urbanization. Oak forests were either completely eradicated and transformed into agricultural landscapes or replaced by second-growth formations. Intensive forest management and the replacement of native forests with production forests or arable lands are recognized amongst the main threats to many lichens in Europe. In this study, we used historical information on the epiphytic lichen biota which was hosted in a native oak-dominated forest of Northern Italy to identify shifts of lichen communities due to the changes in land use which occurred during the last two centuries. We also compared the epiphytic lichen communities inhabiting remnant oak forests with those found in the habitats that have replaced native forests: black-locust forests and agrarian landscapes. Almost all the species sampled during the 19th century are now extinct. The loss of native habitat and the subsequent invasion by black locust were probably the most influential factors which affected the composition of lichen communities, causing the local extinction of most of the species historically recorded. Despite the fact that oak remnants host only a few species which were historically recorded, and that they currently are the lichen poorest habitat in the study region, they host lichen assemblages differing from those of black-locust forests and agrarian stands. In these habitats lichen assemblages are mainly composed of species adapted to well-lit, dry conditions and tolerating air pollution and eutrophication. This pattern is likely to be common also in other lowland and hilly regions throughout Northern Italy where oak forests are targeted among the habitats of conservation concern at the European level. For this reason, a national strategy for biodiversity conservation and monitoring of lowlands forests should provide the framework for local restoration projects.
Article
1. The epiphytic vegetation of 60 stems of aspen (Populus tremula) was studied in a 16-ha forest area near Uppsala, Sweden. The cover of bryophytes and of foliose and fruticose lichens was registered at three heights (50, 100 and 150 cm) around each stem and related to tree factors: bark roughness, bark depth, tree diameter and tree age; to forest conditions: total basal area (approximates tree density including basal area of aspen), light conditions, site quality class and field-layer vegetation type; to bark chemistry: pH, total K, Ca, Mg and Na, and exchangeable K, Ca, Mg and S; and to soil chemistry: pH, total K, Na, Mg, Ca, base saturation and total acidity. 2. Canonical correspondance analysis (CCA, following ter Braak) showed that the most important factors affecting the composition of the epiphytic vegetation were field-layer vegetation type and light conditions, which were correlated with the first axis, and basal area of aspen, soil exchangeable Ca and soil exchangeable Na, which were correlated with the second axis. 3. In multiple regression analyses with individual species as dependent variables, important factors were field-layer vegetation type, bark total Na and soil exchangeable Ca. A high species number was correlated with thick bark and shady conditions. 4. There were significant correlations between bark chemistry and soil chemistry: both exchangeable bark Ca and total bark Ca were significantly correlated with soil pH in multiple regression analyses. Redundancy analysis (RDA, following ter Braak) gave similar results and revealed a positive covariation between bark factors (total Ca, exchangeable Ca, total Na,) and soil factors (pH, soil exchangeable Ca, soil exchangeable Mg). 5. The mechanisms for the connection between soil and bark chemistry are unknown, but several explanations can be postulated, of which an impact from the soil on the bark through transportation of nutrients from the tree roots to the bark seems the most likely. Since bark chemical factors are important for epiphytic species, soil properties might affect the composition of the epiphytic vegetation on Populus tremula. 6. There is a need to investigate further the bark-soil relationships and the mechanisms of possible interactions. If the epiphytic species are indirectly affected by the soil through influences on the bark, this could have consequences for conservation management intended to preserve epiphytic species as well as for the use of bryophytes and lichens as indicators of air pollution.
Article
This study showed that NH(3) emitted from geothermal power plants affects the surrounding epiphytic lichen vegetation and diversity, confounding the interpretation of lichen diversity counts in terms of air pollution by H(2)S. The presence of nitrophytic lichen species around geothermal installations, determined by NH(3), caused relatively high diversity values that were not related with the levels of air pollution by H(2)S. It is recommended that in the presence of NH(3) emission, nitrophytic species are excluded from the calculation of lichen diversity values.
Lichen community change in response to succession in aspen forests of the Rocky Mountains, USA Long distance nitrogen air pol-lution effects on lichens in Europe
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Rogers PC, Ryel RJ. Lichen community change in response to succession in aspen forests of the Rocky Mountains, USA. For Ecol Manage 2008;256:1760–70. Van Herk CM, Mathijssen-Spiekman EAM, De Zwart D. Long distance nitrogen air pol-lution effects on lichens in Europe. Lichenologist 2003;35:347–59. 202 J. Nascimbene et al. / Science of the Total Environment 421–422 (2012) 197–202
Large-scalepatternsofepiphyticlichenspeciesrichness: photobiont-dependent response to climate and forest structure
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MariniL,NascimbeneJ,NimisPL.Large-scalepatternsofepiphyticlichenspeciesrichness: photobiont-dependent response to climate and forest structure. Sci Total Environ 2011;409:4381–6
A thematic contribution to the National Biodiversity Strategy. Plant invasion in Italy, an overview. Roma: Ministry for the Environment Land and Sea Protection
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Analysis of ecological communities Gleneden Beach, Oregon, US: MjM Software Multivariate analysis of ecological data
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The Information System on Italian Lichens. Version 4.0University of Trieste, Dept. of Biology Extractives, acidity, buffering capacity, ash and inorganic elements of black locustwood and bark of different clones and origin
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Nimis PL, Martellos S. ITALIC — The Information System on Italian Lichens. Version 4.0University of Trieste, Dept. of Biology; 2008. IN4.0/1 http://dbiodbs.univ.trieste.it/. Passialis C, Voulgaridis E, Adamopoulos S, Matsouka M. Extractives, acidity, buffering capacity, ash and inorganic elements of black locustwood and bark of different clones and origin. Holz Roh Werkst 2008;66:395–400.
A thematic contribution to the National Biodiversity Strategy. Plant invasion in Italy, an overview
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Celesti-Grapow L, Pretto F, Brundu G, Carli E, Blasi C, editors. A thematic contribution to the National Biodiversity Strategy. Plant invasion in Italy, an overview. Roma: Ministry for the Environment Land and Sea Protection, Nature Protection Directorate; 2009.
Mapping lichen diversity as an indicator of environmental quality Monitoring with lichens, Monitoring lichens
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Trees and shrubs as invasive alien species — a global review
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Richardson DM, Reimánek M. Trees and shrubs as invasive alien species — a global review. Divers Distrib 2011;17:788–809.