Rapid climate change-related growth decline at the southern range edge of Fagus sylvatica

Studies on Fagus sylvatica show that growth in populations toward the southern limit of this species' distribution is limited strongly by drought. Warming temperatures in the Mediterranean region are expected to exacerbate drought where they are not accompanied by increases in precipitation. We studied levels of annual growth in mature F. sylvatica trees over the last half‐century in the Montseny Mountains in Catalonia (northeast Spain). Our results show significantly lower growth of mature trees at the lower limit of this species' distribution when compared with trees at higher altitudes. Growth at the lower Fagus limit is characterized by a rapid recent decline starting in approximately 1975. By 2003, growth of mature trees had fallen by 49% when compared with predecline levels. This is not an age‐related phenomenon, nor is it seen in comparable populations at higher altitudes. Analysis of climate‐growth relationships suggests that the observed decline in growth is a result of warming temperatures and that, as precipitation in the region has not increased, precipitation is now insufficient to ameliorate the negative effects of increased temperatures on tree growth. As the climate‐response of the studied forest is comparable with that of F. sylvatica forests in other southern European regions, it is possible that this growth decline is a more widespread phenomenon. Warming temperatures may lead to a rapid decline in the growth of range‐edge populations and a consequent retreat of the species distribution in southern Europe. Assessment of long‐term growth trends across the southern range edge of F. sylvatica therefore merits further attention.     

The Holocene history of low altitude Mediterranean Fagus sylvatica forests in southern France

Questions

As the dominant tree in many European forests, Fagus sylvatica functions as an ecosystem engineer, yet its istory remains little understood. Here we ask: (a) are there indications for its presence in southeast France during the last Glacial period; (b) what was the timing of the expansion and decline of F. sylvatica dominated forests; (c) which factors influenced their dynamics and in particular to what extent did past precipitation changes impact upon them; and (d) at which altitudes did these beech forests occur within the region?

Location

Languedoc, the French Mediterranean area.

Method

This article presents a well dated and high‐resolution pollen sequence covering the last 7,800 years from the Palavas Lagoon in the Languedoc together with a review of Fagus charcoal occurrences in the Languedoc and the lower Rhône Valley, and a review of pollen data from a compilation of 69 sites in southeast France.

Results

The Palavas pollen sequence provides a regional summary of F. sylvatica abundance changes near the Mediterranean coast. Around 6,000 years cal BP , an abrupt transition from small beech populations to well‐developed forests is recorded. The maximum development of beech forests occurred between 4,000 and 3,000 years cal BP , while F. sylvatica started to regress after 3,000 years cal BP .

Conclusion

Scattered F. sylvatica populations probably survived throughout southern France during the last Glacial period. F. sylvatica started to spread around 8,000 years cal BP while beech forests never expanded before 6,000 years cal BP . The complex patterns of F. sylvatica expansion in southern France after 6,000 years cal BP suggests that a combination of global (climate change) and local (human impact) factors were responsible for this major change. Recurrent abrupt climate changes, the aridity trend and human deforestation caused beech forests to decline after 3,000 years cal BP .

     

Modelling the spread of Fagus sylvatica and Picea abies in southern Scandinavia during the late Holocene

Aim To test the hypothesis that dispersal characteristics alone can explain the past migration patterns of Fagus sylvatica and Picea abies observed in southern Scandinavia. Location Scandinavia, Europe. Methods The spreading dynamics of both species were analysed using a quantitative data–model comparison approach. Pollen data recording the arrival of the two species at 24 small forest‐hollow sites distributed across the study area were compared with simulated arrival times. The simulations were based on diffusive spread combined with long‐distance dispersal events. By systematically applying different parameter combinations yielding the desired colonization speeds we could identify values for the long‐distance dispersal component that minimized deviations from the observed arrival times. Results According to the minimization process, the optimal spreading rates were 100 m year^?1 for F. sylvatica and 250 m year^?1 for P. abies. Simulated dispersal alone could adequately explain the wave‐like spread of P. abies but failed to explain the scattered establishment pattern observed for F. sylvatica in Scandinavia. At the fine scale of stand establishment, local microclimatic conditions or site disturbance might be more important. The estimated spreading rates are high because the species colonized Scandinavia from different geographic directions and the rates slowed when their ranges overlapped. We present new estimates for the distance and frequency of long‐distance dispersal events for our modelled species. Main conclusions Our analyses suggest that the late Holocene spread of P. abies in Scandinavia was fairly rapid and was limited only by biological processes of dispersal, while that of F. sylvatica was limited by other factors probably controlled by site properties. Picea abies has maintained a rapid and constant rate of spread throughout at least the last 4000 years, despite significant changes in climate. There is uncertainty about the precise relationship between P. abies and climate in Scandinavia, so future distributions are not easy to forecast. For F. sylvatica in Scandinavia, site quality appears to have been a limiting factor, so future land use is likely to dictate its future distribution dynamics in combination with climatic factors.     

Drought-driven growth reduction in old beech (Fagus sylvatica L.) forests of the central Apennines, Italy

Productivity of old‐growth beech forests in the Mediterranean Basin was measured by average stem basal area increment (BAI) of dominant trees at two mountain sites in the Italian Apennines. Both forests could be ascribed to the old‐growth stage, but they differed markedly with regard to elevation (1000 vs. 1725 m a.s.l.), soil parent material (volcanic vs. calcareous), mean tree age (less than 200 years vs. 300 years), and stand structure (secondary old‐growth vs. primary old‐growth forest). Drought at the two sites was quantified by the self‐calibrated Palmer Moisture Anomaly Index (Z‐index), and by the self‐calibrating Palmer Drought Severity Index (PDSI) for summer (June through August) and the growing season (May through September). Dendroclimatological analyses revealed a moisture limitation of beech BAI at interannual (water availability measured by Z‐index) and decadal scales (water availability measured by PDSI). Both BAI and water availability increased from 1950 to 1970, and decreased afterwards. Trees were grouped according to their BAI trends in auxological groups (growth‐type chronologies), which confirmed that growth of most trees at both sites declined in recent decades, in agreement with increased drought. Because BAI is not expected to decrease without an external forcing, the patterns we uncovered suggest that long‐term drought stress has reduced the productivity of beech forests in the central Apennines, in agreement with similar trends identified in other Mediterranean mountains, but opposite to growth trends reported for many forests in central Europe.     

Genetic structure and phylogeographic relationships of Fagus sylvatica L. woods in Lazio (Central Italy)

The genetic characterisation of beech woods in Lazio was performed by microsatellite approach. The phylogeographic relationship existing among stands was investigated, allowing us to identify a putative glacial refugium for this species. This work provides information for management policies and conservation strategies of F. sylvatica germplasm resources in central Italy.     

Confirmation of the nomenclatural status ofMalassezia pachydermatis

Malassezia strains from dogs and rhinoceros all proved identical using mole % G + C and nDNA/DNA reassociation experiments. The use of the nameMalassezia pachydermatis, originally described for a strain isolated from a rhinoceros, is thus justified for non lipid-dependent strains of other sources.     

Nomenclatural remarks on the chasmophytic vegetation of the Centaureo-Campanuletalia

The thermophilous chasmophytic vegetation on limestone of the Adriatic Region has been arranged in the endemic order Centaureo-Campanuletalia (class Asplenietea trichomanis). The distribution range of the order covers a large area around the Adriatic Sea – from the south and north east of Italy to Slovenia, Croatia, Bosnia i Hercegovina, Montenegro and Albania. The Centaureo-Campanuletalia or its subordinated syntaxa are quoted in the main syntaxonomic synopses of the Region as well as in technical reports. The critical analysis of the nomenclature of the order, based on the International Code of Phytosociological Nomenclature (ICPN), showed many invalid or incorrect names while it is evident that the usage of correct names in scientific literature is crucial, both for the advances of syntaxonomic knowledge and their application for practical purposes. This paper presents a revision of the nomenclature for the Centaureo-Campanuletalia and related syntaxa in order to stabilize this nomenclature at least at alliance level. As a result, three syntaxa were validated (Centaureo dalmaticae-Campanuletalia pyramidalis, Centaureo cuspidatae-Portenschlagiellion ramosissimae, Inulo verbascifoliae-Centaureetum cuspidatae) and five others were lectotypified.     

Mesophilous woods with Fagus sylvatica L. of northern Latium (Tyrrhenian Central Italy): synecology and syntaxonomy

ABSTRACT

The results of a synecological and syntaxonomic study of mesophilous forest coenoses, mixed or with a prevalence of Beech, in northern Latium (Roman Tuscia), are reported. The main parameters determining the distribution pattern and floristic composition of these coenoses were altitude, exposure, acclivity, asperity and ecotope. The presence of Aquifolio-Fagetum (Doronico-Fagion) at la Tolfa and in the Sabatini Mts. is confirmed, together with the autonomy of Teucrio siculi-Quercion cerridis and Lathyro-Quercion cerridis in the Cimini-Vicani and Sabatini Mts. and on the sandstone substrates of Mt. Rufeno, respectively. Variants of Polysticho-Fagetum aceretosum pseudoplatani (Galio odorati-Fagenion) with Polystichum setiferum and with Veronica hederifolia were recognized in certain parts of the Cimini and Vicani Mts. The presence of Carpinion betuli, especially with Carpino-Coryletum avellanae and the new subassociation phyllitiaetosum scolopendrii of the latter, is recognized in gullies and ravines eroded in tufo of the Vulsino and Cimino complexes.     

A contribution to understanding the internal nitrogen budget of beech (Fagus sylvatica L.)

Summary The seasonal variation in the total nitrogen content of the xylem sap of the lower trunk section was investigated for two middle aged beech tree stands in northern Hessen each containing 130 trees. In addition seasonal changes in the percentage of nitrate in the total nitrogen content are described. The median values of the total nitrogen content of the xylem sap during the spring mobilization period reached 175 and 250 mg/l. During the summer about 35% of the total nitrogen in the xylem sap is in the form of nitrate. Finally, the distribution of NO₃ in the xylem sap along the trunk height was studied for two sample trees for each of the four seasons (n = 8).     

New syntaxonomic contribution to the Vegetation Prodrome of Italy

New syntaxa of different hierarchical levels are here described in order to update the “Syntaxonomic checklist of the Italian classes, orders and alliances (Vegetation Prodrome of Italy)”, promoted in 2012 by the “Ministry of Environment, Land and Sea Protection” in collaboration with the “Italian Society of Botany”. The new alliances, suballiances and associations belong to the Salici purpureae-Populetea nigrae and Querco roboris-Fagetea sylvaticae classes.     

Towards an understanding of the Holocene distribution of Fagus sylvatica L.

Aim Understanding the driving forces and mechanisms of changes in past plant distribution and abundance will help assess the biological consequences of future climate change scenarios. The aim of this paper is to investigate whether modelled patterns of climate parameters 6000 years ago can account for the European distribution of Fagus sylvatica at that time. Consideration is also given to the role of non‐climatic parameters as driving forces of the Holocene spread and population expansion of F. sylvatica. Location Europe. Methods European distributions were simulated using a physiologically‐based bioclimatic model (STASH) driven by three different atmospheric general circulation model (AGCM) outputs for 6000 years ago. Results The three simulations generally showed F. sylvatica to have potentially been as widespread 6000 years ago as it is today, which gives a profound mismatch with pollen‐based reconstructions of the F. sylvatica distribution at that time. The results indicate that drier conditions during the growing season 6000 years ago could have caused a restriction of the range in the south. Poorer growth conditions with consequently reduced competitive ability were modelled for large parts of France. Main conclusions Consideration of the entire European range of F. sylvatica showed that no single driving force could account for the observed distributional limits 6000 years ago, or the pattern of spread during the Holocene. Climatic factors, particularly drought during the growing season, are the likely major determinants of the potential range. Climatic factors are regionally moderated by competition, disturbance effects and the intrinsically slow rate of population increase of F. sylvatica. Dynamic vegetation modelling is needed to account for potentially important competitive interactions and their relationship with changing climate. We identify uncertainties in the climate and pollen data, as well as the bioclimatic model, which suggest that the current study does not identify whether or not climate determined the distribution of F. sylvatica 6000 years ago. Pollen data are better suited for comparison with relative abundance gradients rather than absolute distributional limits. These uncertainties from a study of the past, where we have information about plant distribution and abundance, argue for extreme caution in making forecasts for the future using equilibrium models.     

The effects of acclimation to sunlight on the xylem vulnerability to embolism in Fagus sylvatica L.

We assessed the effects of irradiance received during growth on the vulnerability of Fagus sylvatica L. xylem vessels to water-stress-induced embolism. The measurements were conducted on (1) potted saplings acclimated for 2 years under 100% and 12% incident global radiation and (2) branches collected from sun-exposed and shaded sides of adult trees. Both experiments yielded similar results. Light-acclimated shoots were less vulnerable to embolism. Xylem water potential levels producing 50% loss of hydraulic conductivity were lower in sun-exposed branches and seedlings than in shade-grown ones (–3·0 versus –2·3 MPa on average). The differences in vulnerability were not correlated with differences in xylem hydraulic conductivity nor vessel diameter. Resistance to cavitation was correlated with transpiration rates, midday xylem and leaf water potentials in adult trees. We concluded that vulnerability to cavitation in Fagus sylvatica may acclimate to contrasting ambient light conditions.     

Increased growth and reduced summer drought limitation at the southern limit of Fagus sylvatica L., despite regionally warmer and drier conditions

Tree populations at the equatorward edge of their distribution are predicted to respond to increased temperature and drought with declining performance. Empirical studies of Fagus sylvatica L., one of the most studied tree species in Europe, have broadly supported these predictions. Using a network of tree ring chronologies from northern Greece, we showed that growth in populations of this species at their southeast distribution limit was limited by summer temperature and precipitation, particularly at low elevations. Furthermore, decadal periods of lower precipitation and higher temperature in the twentieth century were associated with multi-year growth depressions. However, since 1990, growth trends were positive across the network, despite continued dry and hot summer conditions. Growth trends were not correlated with either elevation or tree age. Additionally, correlations between growth and temperature and precipitation were weaker in recent decades. These results are consistent with another recent report from the Balkan Peninsula, and indicate that forests in this region may be more resistant to regional climate change than previously considered.     

Assessment of genetic relationships and population discrimination among Fagus sylvatica L. by RAPD

 We assessed the genetic relationships between members of the Fagaceae family by RAPDs in order to better ascertain the taxonomic status of a very particular population of Fagus sylvatica, the ‘tortuosa’ variety. Intra- and inter-population Nei and Li’s mean genetic distances were compared, and the genetic relationships between individuals were clarified on dendrograms by the Neighbor joining method. RAPD analysis was first conducted on three species from three genera, Quercus petraea, Castanea sativa, and Fagus sylvatica, in order to develop an efficient RAPD protocol. The variety level was then studied, and a general tendency of the individuals to cluster by variety was observed. Individuals also clustered by geographic locations, but the genetic distances between populations were not correlated to the distances between sites. Finally, we compared the common beech and ‘tortuosa’ varieties from two different locations, Verzy and Süntel. Both populations from one location were closer than the same variety from two sites. This last result is in agreement with those previously obtained with isozymes. Hypotheses concerning the origin of the ‘tortuosa’ variety are discussed. Received: 9 January 1998 / Accepted: 25 February 1998     

Contribution to the knowledge of the veterinary science and of the ethnobotany in Calabria region (Southern Italy)

This paper explores the use of the dried meat and feathers of the Andean Flicker (Colaptes rupicola) to increase the milk supply of nursing women and domestic animals in the Andes. The treatment is of preColumbian origin, but continues to be used in some areas, including the village in the southern Peruvian highlands where I do ethnographic research. I explore the factors giving rise to and sustaining the practice, relate it to other galactagogues used in the Andes and to the use of birds in ethnomedical and ethnoveterinary treatments in general, and situate it within the general tendency in the Andes and elsewhere to replicate human relations in the treatment of valuable livestock. The bird's use as a galactagogue appears to be motivated by both metaphorical associations and its perceived efficacy, and conceptually blends human and animal healthcare domains.     

Physiological responses of Fagus sylvatica L. exposed to low levels of ozone in open-top chambers

Four-year-old beech seedlings were fumigated with three levels of ozone for 2 consecutive years in open-top chambers. During the second growth season different physiological measurements were conducted before and during daily fumigation. A 25–40% decrease in net photosynthesis was seen during fumigation, whereas no differences were detected before fumigation in July. In August lasting effects in net photosynthesis were seen. The apparent quantum yield was decreased after fumigation. Stomatal conductance was generally decreased during fumigation, but transpiration was reduced relatively less than net photosynthesis indicating a lower water use efficiency of the trees exposed to ozone. Chlorophyll fluorescence (F_v/F_m) showed additive reductions in relation to ozone and light.