Plant species diversity changes in abandoned chestnut (Castanea sativa) groves in southern France

Over the last few decades, marked land use changes have taken place in many Mediterranean ecosystems. For example, many chestnut groves in France are now abandoned and have turned into 'natural' coppice stands while others are now clear-cut every 10 or 15 years for wood. Species composition and life form diversity of the plant communities have changed markedly both in the abandoned groves and in the periodically clear-cut coppice stands. What are the consequences of these changes on biodiversity at local and regional scales, and what are the implications for 'new forestry' management intended to conserve biodiversity at the same time as it optimizes productivity and profitability? To answer these questions we studied plant species diversity in the understorey strata along a successional gradient including cultivated grove; abandoned grove; young (15 years old), medium (40 years), and old (>55 years) coppice stands. The results showed that species richness decreased quickly but not steadily along this gradient, but life-form spectra data highlighted that the high levels of plant species biodiversity in cultivated groves were due primarily to the large number of therophytes (annual plants). At a shorter time scale, we also studied the consequences of experimental clear-cutting on plant species biodiversity. Direct measurements over four years showed that species richness and diversity in the understorey increased in the first two years after clear-cutting, but decreased during the 3rd and 4th years. This decrease corresponded closely with a steady increase in Leaf Area Index of the forest canopy. These results have been used to suggest some possible ways to manage the biodiversity in these ecosystems.     

Role of domestication in shaping <Emphasis Type="Italic">Castanea sativa</Emphasis> genetic variation in Europe

The genetic structure of sweet chestnut (Castanea sativa Mill.) across Europe was assessed using 73 inter-simple sequence repeat markers to screen 1,768 individuals from 68 stands distributed across 29 sites in five European countries (Italy, France, Spain, Greece, and UK). At each site, trees were sampled from three distinct management types (domestication levels): naturalized stands, managed coppice, and grafted fruit orchards. In more than a third of the orchards, nonlocal genetic material (grafted clones) were evident, showing (as predicted) large differences from the other two domestication levels for most of the within-population genetic diversity parameters estimated. Randomly generated linkage disequilibrium analysis revealed weak though significant differences in two-locus allelic correlations between naturalized stands and coppice, suggesting that long-term management techniques may influence the genetic makeup of the populations. Multivariate analysis revealed the existence of five distinct gene pools across the study area; three were located in Greece, one on the northwestern coast of the Iberian peninsula and a large gene pool covering the rest of the Mediterranean basin. The implications of the results are discussed in relation to developing conservation strategies for chestnut genetic resources in Europe.     

Biodiversity conservation and forest management: The case of the sweet chestnut coppice stands in Central Italy

The ecological and economic relevance of sweet chestnut (Castanea sativa Mill.) has long been related to its widespread geographical distribution and multipurpose product potential. In Central Italy, chestnut management represents a paradigmatic example of the potential conflict between landowner targets and biodiversity conservation: options for preserving stand-scale biodiversity are not fully considered as current management is based on monospecific, even-aged coppice stands and clearcutting on wide areas. Relationships between silvicultural treatment and floristic diversity of chestnut coppices are here investigated focusing the attention on rotation length and on the role of thinning. Seven coppice stands were selected in such a way to be of similar size (about 10 ha) and to cover a wide range of ages and a different number of thinnings. Plot sampling was performed across the stands and their floristic diversity was compared and analyzed by means of indicators in order to assess statistical relationships between floristic data and stand structural attributes. The achieved results suggest alternative suitable options for managing chestnut coppice stands in order to enhance biodiversity while maintaining wood production.     

Taxonomy and ecology of <Emphasis Type="Italic">Castanea sativa</Emphasis> Mill. forests in Greece

Castanea sativa Mill. is an important species of the Balkan Peninsula with high ecological and economic value. This article contributes to a phytosociological synsystematic approach of the C. sativa plant communities in Greece that covers the southern part of the Balkan Peninsula and describes the ecological parameters involved in their distribution and taxonomy. Phytosociological data have been collected from 14 mountainous areas across continental Greece, which are considered representative of the main forest types of C. sativa in the area. The 14 mountains demonstrate a variety of environmental conditions. Five communities (associations) and seven sub-communities (sub-associations) have been identified and described using TWINSPAN, Corespondence Analysis and the Braun-Blanquet classification scheme. Castanea sativa (chestnut) forests of Greece can be distinguished as three broad groups, defined primarily by their geographical distribution. In northern and central Greece chestnut stands are characterized by their high floristic homogeneity, which is reflected in the identification of only one community per region. Chestnut forests in northern Greece, in particular, exhibit strong floristic similarities with those of the rest of the Balkans. In southern Greece, on the other hand, the southern distribution limit of chestnut in the Balkans, there is a greater floristic diversity between the sampled mountains which is reflected in the presence of three confirmed communities and two sub-associations. Several factors have been identified as important in determining the structure and floristic composition of chestnut forests in Greece. Whilst climate and the grazing regime are influential, the degree of silvicultural management appears to be the most important factor determining the floristic composition of chestnut forests and their long-term sustainability.     

Correlation among soil enzyme activities under different forest system management practices

Soil enzyme activities were performed in three permanent no-till and unfertilised plots located in the South of Salamanca province (Spain), the first in a Castanea sativa Mill. paraclimax coppice (CC), the second in a chestnut orchard (CO) and the third in a Quercus pyrenaica Wild. climax forest (Oak), adjacent to the CO plot.We hypothesized that the activities of dehydrogenases, ureases, acid phosphatases, arylsulphatases and β-glucosidases in different forest ecosystems are involved in the carbon, nitrogen and phosphorus cycling and we report their relationship with each other and with physical, chemical and general biochemical parameters of the soils. The main aim of the study was to detect biological criteria for sustainable development in natural degenerate forests of Mediterranean Europe. For this, we used sweet Chestnut (C. sativa Mill) and Oak Q. pyrenaica Wild as models to better define the ecological conditions of these natural resources in terms of nutrient balance, physiology and biological diversity of their communities, to relate them to the conditions of exploitation and land-use changes, for the characterization of sustainable ecological systems.Furthermore, soil respiration was high and significantly different in the chestnut coppice stand than the other two stands, chestnut orchard and oak.Correlations between soil biochemical and soil microbiological variables showed that the three different forest management practices had also a strong effect on soil function conditions. In a discriminate analysis, CC and Oak were discriminated clearly, while CO was in the middle of the biplot sharing some properties with each of the two different groups. Thus, we proposed a soil property transition from the best soil structure and function properties at one chestnut management properties with low tree densities (CC and CO) to other with the worst ones at highest tree density conditions (Oak). According to natural soil conditions in Oak, we assumed that most of the enzyme activities reached their highest levels at highest C and N soil contents but at lowest soil base saturation percentage while they were not at all associated with P soil availability.     

Radial-growth and wood-anatomical changes in overaged Quercus pyrenaica coppice stands: functional responses in a new Mediterranean landscape

Recent land-use changes in intensively managed forests such as Mediterranean coppice stands might profoundly alter their structure and function. We assessed how the abandonment of traditional management practices in coppice stands, which consisted of short cutting-cycles (10–15 years), has caused overaging (stems are usually much older than when they were coppiced) and altered their wood anatomy and hydraulic architecture. We studied the recent changes of wood anatomy, radial growth, and hydraulic architecture in two stands of Quercus pyrenaica, a transitional Mediterranean oak with ring-porous wood forming coppice stands in W–NW Spain. We selected a xeric and a mesic site because of their contrasting climates and disturbance histories. The xeric site experienced an intense defoliation after the severe 1993–1994 summer drought. The mesic site was thinned in late 1994. We studied the temporal variability in width, vessel number and diameter, and predicted the hydraulic conductivities (K _h) of earlywood and latewood. In the mesic site, we estimated the vulnerability to xylem cavitation of earlywood vessels. Overaging caused a steep decline in latewood production at a cambial age of 14 years., which was close to the customary cutting cycle of Q. pyrenaica. The diameter distribution of vessels was bimodal, and latewood vessels only accounted for 4% of the K _h. Overaging, acting as a predisposing factor in the decline episode, was observed at the xeric site, where most trees did not produce latewood in 1993–1995. At the mesic site, thinned trees formed wider tree-rings, more latewood and multiseriate tree-rings than overaged trees. The growth enhancement remained 8 years after thinning. Most of the hydraulic conductivity in earlywood was lost in a narrow range of potentials, between −2.5 and −3.5 MPa. We have shown how hydraulic conductivity and radial growth are closely related in Q. pyrenaica and how aging modulates this relationship.     

The effect of coppice management on moth assemblages in an English woodland

Coppice woodlands in Britain may become the target of increased management due to the rise in demand for woodfuel. The biodiversity value of sweet chestnut (Castanea sativa) coppice and the effect of coppice management upon this has received limited study. Moths were the focus of this study in an actively coppiced sweet chestnut woodland in southern England. Coupes, with between one and 20 years of coppice regrowth, were systematically sampled for night flying micro- and macro-moths and coppice structure and ground vegetation were described. Using differences in moth assemblage, three stages of coppice development were distinguished: with one-four, five-nine and more than 10 years of coppice regrowth. Differences in moth assemblage related to habitat conditions within each coppice stage. The young coppice stage moth assemblage was characterised by species typically associated with open habitats; moths of the middle coppice stage assemblage fed on trees and were species typically associated with open woodland and scrub habitats; moths of the mature coppice stage assemblage were species typically associated with closed canopy woodland and contained specialist species whose larval food consists of material such as lichen and decaying leaves. All three coppice stages supported species of listed conservation status; the mature coppice stage contained a distinctive range of scarce and threatened species. The study showed that active coppicing promotes a change in moth assemblage but consequently will temporarily eliminate many species of mature stage coppice. Management which provides a range of coppice age classes within a woodland, appears key in promoting moth diversity.     

Assessing the effects of forest management on epiphytic lichens in coppiced forests using different indicators

Abstract

Epiphytic lichens are one of the taxonomic groups most sensitive to forest management. Nevertheless, they have not yet been exhaustively included in the assessment of Sustainable Forest Management. This work aimed at evaluating the effects of forest management on epiphytic lichens in coppiced forests, exploring the spatial patterns of diversity and the composition of communities. Moreover, the goal was to compare the performance of four potential indicators for monitoring the effects of forest management on epiphytic lichens: total lichen diversity, species associated with intensive management, species associated with aged coppiced woodlands and Indicator Species Ratio (ISR). In humid Mediterranean Liguria, 50 sampling units were chosen in Castanea sativa and deciduous Quercus spp. forests subjected to different forest management practices: intensively managed coppice and aged coppice/high forest. The effect of forest management was evident in terms of species composition, since it was possible to find significantly associated species for each of the two management types. At each sampling site, the four indicators were calculated using Indicator Value Analysis and compared through correspondence analysis. The ISR was shown to be a more effective indicator, being independent of floristic composition and the occurrence of rare species.     

Community homogenization and the invasiveness of commensal species in Mediterranean afforested landscapes

The ecological consequences of homogenization remain relatively unexplored. One example of landscape-homogenizing is the establishment of plantations. We studied the effect of human-made forests by contrasting plant and small-mammal community composition between planted tree stands and adjacent natural habitat in two different Mediterranean habitats in Israel: (1) inland habitat where we focused on pine (Pinus halepensis) and carob (Ceratonia siliqua) stands, and (2) coastal sand dune habitat where we focused on planted acacia (Acacia saligna) stands. We first wanted to verify whether planted trees modify plant species composition, and second, if and how the small-mammal community is affected by the different habitat conditions created in plantations with different canopy cover. We were especially interested in the abundance of the commensal house mouse (Mus musculus). All tree stands underwent biotic homogenization indicated by abundance of house mice coupled with lower diversity of indigenous vegetation and small-mammal abundances and diversities. Habitat structural diversity was positively related with small-mammals diversity and was lower in artificial tree stands in both habitats. Our results suggest that using the abundance of commensal generalist species such as the house mouse relative to other more specialist small-mammals is a good approach to determine ecosystem integrity. Pre-commercial thinning treatment is a potential management tool to maintain a proportion of native tree species within the canopy of planted tree stands. However, until sufficient data is available for making generalizations, the exact level of thinning necessary to reverse the homogenization processes in man-made plantations and keeping indigenous small-mammal communities diverse and less prone to invasion must be determined empirically.     

Tree Diversity Limits the Impact of an Invasive Forest Pest

The impact of invasive herbivore species may be lower in more diverse plant communities due to mechanisms of associational resistance. According to the “resource concentration hypothesis” the amount and accessibility of host plants is reduced in diverse plant communities, thus limiting the exploitation of resources by consumers. In addition, the “natural enemy hypothesis” suggests that richer plant assemblages provide natural enemies with more complementary resources and habitats, thus promoting top down regulation of herbivores. We tested these two hypotheses by comparing crown damage by the invasive Asian chestnut gall wasp (Dryocosmus kuriphilus) on chestnut trees (Castanea sativa) in pure and mixed stands in Italy. We estimated the defoliation on 70 chestnut trees in 15 mature stands sampled in the same region along a gradient of tree species richness ranging from one species (chestnut monocultures) to four species (mixtures of chestnut and three broadleaved species). Chestnut defoliation was significantly lower in stands with higher tree diversity. Damage on individual chestnut trees decreased with increasing height of neighboring, heterospecific trees. These results suggest that conservation biological control method based on tree species mixtures might help to reduce the impact of the Asian chestnut gall.     

Landscape genetic structure of chestnut (Castanea sativa Mill.) in Spain

The current need for forest conservation and management has driven a rapid expansion of landscape genetics approach. This discipline combines tools from molecular genetics, landscape ecology and spatial statistics and is decisive for improving not only ecological knowledge but also for properly managing population genetic resources. This approach could be appropriate to sweet chestnut (Castanea sativa Mill.), a multipurpose species of great economic importance in the Mediterranean basin and a species considered to be a good model of integration between natural and human-driven distribution of diversity. Sixteen chestnut populations, covering the distribution range of the species in Spain, were analysed using seven microsatellite markers. Results revealed a high level of genetic diversity in Spanish chestnut populations, which in part followed a geographical pattern, although distribution was not homogeneous. Likewise, areas particularly rich in diversity were detected, facilitating the development of a hypothesis about the history of chestnut in Spain. In conclusion, these results provide valuable baseline data for more in-depth studies on chestnut landscape genetics that can contribute to its conservation.     

Genetic resilience in a historically profited root sprouting oak (Quercus pyrenaica Willd.) at its southern boundary

Recent land use changes entailed the abandonment of traditional forest practices, which genetic and ecological sustainability should be evaluated in the frame of current socioeconomic and ecological changes. The present study aimed to assess the conservation value of Quercus pyrenaica Willd. in stands subjected to two traditional rural practices, one specific (coppicing) and the other generic (maintenance of open parklands), and their effects on genetic diversity and clonal structure in this singular root sprouting oak at the southern limit of its distribution. Genetic diversity measures of seven nuclear simple sequence repeat markers were compared, and Hardy–Weinberg disequilibria were tested to be originated from recent population demography. Results showed that, regardless of forest structure, the degree of clonality was very similar (～60 %), being allele and lineage density proportional to stem density. Nevertheless, evenness of clonal distribution was higher in coppice, suggesting more homogeneous management than in open woodland. Contrary to previous beliefs, coppice stands do not involve genetic diversity losses; rather, the process of forest conversion into open woodland leads to the removal of numerous genetic lineages and low frequency alleles. The ancient presence of Q. pyrenaica in the region, which constituted quaternary glacial refuge, may contribute to its high genetic diversity. Historical vicissitudes in this anthropogenic deforested territory remark its resilient character; based on a specific fire pre-adaptive trait, continued coppicing fostered the preservation of its natural genetic diversity. This study evidences the importance of the integration of molecular and historical approximations to assess the genetic and conservation status of a secularly profited woody species.     

Genetic diversity of the sweet chestnut (<Emphasis Type="Italic">Castanea sativa</Emphasis> Mill.) in Central Europe and the western part of the Balkan Peninsula and evidence of marron genotype introgression into wild populations

The sweet chestnut (Castanea sativa Mill.) is a widely spread and important multipurpose tree species in the Mediterranean area, which has played an important role in human history. Natural events, such as glaciations, and human influence played significant roles in the distribution and genetic makeup of the sweet chestnut. In order to better understand how natural and human-mediated past events affected the current genetic diversity and structure of the sweet chestnut, we analysed populations from Central Europe and the western part of the Balkan Peninsula, utilizing ten polymorphic nuclear microsatellite markers. The study revealed the existence of three genetically and, to a large extent, geographically distinct and well-defined groups of sweet chestnut populations. Two not entirely separated groups of populations were detected in the northern part of the studied area and one in the southern. Our results indicate that the genetic structure of sweet chestnut populations in Central Europe and the western part of the Balkan Peninsula is the result of both natural colonization events and significant and lengthy human impact. Furthermore, it has been proven that the gene flow between cultivated/grafted trees’ and wild chestnut stands can influence their genetic structure. However, our results reveal that cultivated-to-wild introgression in the sweet chestnut is dependent on the close proximity of chestnut orchards and naturally occurring populations.     

Post hibernation dispersal of three leaf-eating beetles (Coleoptera: Chrysomelidae) colonising cultivated willows and poplars

1 We studied the spring dispersal of three common chrysomelids, from overwintering habitats into cultivated willow and poplar coppices at four sites in southern England over 2 years. 2 Adult Galerucella lineola, Phratora vulgatissima and P. vitellinae overwintered under the bark of mature trees or in other niches that simulated this habitat, within a few hundred metres of the coppice plantation. Relatively few beetles remained in the coppice fields during the winter. 3 Phratora vitellinae at the poplar sites emerged several weeks later than G. lineola and P. vulgatissima at the willow sites, reflecting the later leafing of poplar compared to willow. For all species, dispersal was by flight, with most activity during warm periods. Dispersal continued for several weeks for the willow- feeding species but was shorter for P. vitellinae. 4 All three species initially colonized the edge of the coppice field. Typically, 80% or more of the beetles colonising a plantation were within 8 m of the edge. Both Phratora spp. accumulated in the plantation edge zone for several weeks before leaving this area and colonising the crop interior. 5 The patterns of dispersal and colonization identified by this study may facilitate chrysomelid management practices in infested short rotation coppice that avoid the need for insecticide applications over the entire plantation. Keywords Chrysomelidae, Galerucella lineola, Phratora vitellinae, Phratora vulgatissima, poplar, short rotation coppice, willow, winter dispersal.     

The role of the perch effect on the nucleation process in Mediterranean semi-arid oldfields

Oldfield succession in Mediterranean ecosystems has been studied extensively in mesic conditions. However, this phenomenon is still poorly understood in semi-arid Mediterranean areas, where reduced plant cover, the importance of facilitation processes and the role of abiotic factors make these environments distinct. We first test whether the carob tree (Ceratonia siliqua) generates nucleation patterns in semi-arid oldfields, and to what extent such patterns change with abandonment age. Then we test to what extent nucleation can be explained by the perch effect. And finally, we test whether the nucleated pattern around carob trees is a source of diversity in the oldfields studied. To answer these questions we located oldfields abandoned 25 and 50 years ago (20 in each case) in the Alacant Province (SE Spain, Iberian Peninsula) on the basis of aerial photographs and personal interviews with local landowners and managers. In each oldfield woody plant density and richness were sampled on two microsites: under the carob tree and in the open field. Analysis was performed on all woody plants and by separating the species in two functional groups: fleshy-fruited (with fleshy mesocarp) and non-fleshy-fruited species. The results suggest that woody vegetation colonising abandoned C. siliqua fields in SE Spain is not randomly distributed but follows a nucleation pattern with higher plant density under the trees. However, the nucleation pattern is only significant for fleshy-fruited species, suggesting that facilitative interactions alone cannot explain the nucleation pattern and that the perch effect plays an important role. The results also show that the nucleation pattern (total plant density and density of non-fleshy-fruited plants) did not increase with abandonment age, while the perch effect (density of fleshy-fruited plants) did increase significantly. Furthermore, the results also show that the nucleation pattern is not only a loci of high plant density but also a loci of high species richness. Thus we can conclude that the nucleation pattern found in oldfield succession is best explained by the perch effect, while facilitation has a secondary importance. This emphasises the key role that dispersal mode has on the dynamics of vegetation recovery in formerly cropped areas.     

Unravelling mechanisms of short-term vegetation dynamics in complex coppice forest systems

The silvicultural management of coppicing has been very common in deciduous forests in many European countries. After decades of decline of this practice, socio-economic changes might induce a revival valuing the biomass as a resource. New insights in the ecological processes that regulate plant diversity are relevant for a sustainable forest management. While studies on long-term changes are available, the short-term dynamics of the coppice forest understorey has not yet been explored. In this context, it is interesting to evaluate the species compositional changes, including the processes of species turnover and species impoverishment (nestedness) and to investigate the role of plant functional traits. For this purpose, we resampled a chronosequence of complex coppice beech forests of the Central Apennines (Italy) monitoring the short-time species dynamics of five years (i.e. from 2006 to 2011) in three age classes, i.e. post-logged, recovering and old coppice stands (0–16, 17–31 and > 32 years, respectively). In contrast to our expectation, declining species richness appeared only in the recovering stands, while the landscape scale (between-stand) heterogeneity, except for post-logged and recovering stands in 2011, did not change over five years. Significant temporal nestedness was found in each stage of succession. However, the rate of species turnover and species impoverishment do not significantly differ among the three age classes, indicating their constant importance along the forest regeneration after disturbance. Only in the early stage of forest regeneration after coppicing, species compositional changes are reflected by functional changes with surviving understorey species having clonal regeneration traits. Our results suggest an overall landscape-scale stability (and sustainability) of this coppice forest system. We conclude with management indications, highlighting the importance of maintaining the traditional local approach (coppicing with standards in small 0.5–1.0 ha sized management units with a ca 30-year rotation cycle) where active coppice parcels are interspersed by abandoned stands.     

Long‐term effects of the abandonment of grazing on steppe‐like grasslands

Question: What are the consequences of grazing abandonment on the Stipa lessingiana dominated steppe‐like grasslands? What is the relative importance of management and environmental factors in causing variation in species composition and abundance in the continuously grazed and abandoned grassland stands? Location: Transylvanian Lowland, Romania. Methods: Repeated vegetation mapping of a grassland stand, where grazing was abandoned 35 years ago; re‐sampling six grassland stands surveyed 29–57 years ago. For revealing long‐term changes in species composition and rank abundance PCoA ordination was applied. The relative importance of management and environmental factors in structuring vegetation were explored by CCA ordination. Diversity, evenness and the relative number and abundance of red‐listed species were compared between managed and abandoned stands. Results: Our results pointed out that grasslands which were formerly grazed and dominated by S. lessingiana, in the long‐term absence of grazing, have been transformed into a S. pulcherrima dominated type. Management, probably by creating bare surfaces and preventing litter accumulation, had the strongest effect on the species composition and abundance in the grasslands. Abandoned grassland stands had lower diversity and evenness compared to continuously grazed stands. While at the same time, the relative number of threatened, rare species did not differ between managed and abandoned sites. Conclusion: Maintaining extensively grazed, as well as un‐managed, Stipa dominated grasslands would be important in order to create various habitat conditions for plant species, especially threatened and rare species, and promote diversity on the landscape scale.     

Centenary coppicing maintains high levels of genetic diversity in a root resprouting oak (<Emphasis Type="Italic">Quercus pyrenaica</Emphasis> Willd.)

Studies disentangling the anthropogenic influences of traditional forest uses are crucial to assess the current conservation value of cultural landscapes. By promoting asexual regeneration, centenary coppicing in the predominantly root resprouter Quercus pyrenaica is assumed to have reduced genetic diversity levels contributing to the decline of abandoned coppices and the common lack of acorn production. This work aims to test the widespread assumption that historical coppicing in Q. pyrenaica has caused depleted levels of genetic diversity. Seven microsatellite markers were used to assess clonal structure and population genetic diversity levels in six abandoned coppices of Q. pyrenaica, which were compared to three open woodlands in national parks in Spain. Asexual regeneration was higher in coppices, leading to more frequent and larger clonal assemblies. Clonal diversity parameters (genotypic richness and proportion of unique genotypes) were significantly lower in coppices, although density of genotypes per surface area and levels of population genetic diversity were comparable to those observed in open parklands. Heterogenic clonal structures were found both within and among stands, hindering the inference of concrete anthropogenic disturbances. Despite promoting asexual reproduction, coppicing maintains high levels of genotypic and genetic diversity and allows the incorporation of new genotypes by seed recruitment. The natural resprouting capacity of Q. pyrenaica preserved the species in face of long-lasting anthropogenic disturbances, fostering ecosystem resilience and harbouring high conservation values.     

Origins and genetic conservation of tropical trees in agroforestry systems: a case study from the Peruvian Amazon

Hundreds of native tree species are currently found in extensive agroforestry ecosystems in the Peruvian Amazon, forming an important reservoir of biodiversity. To further promote conservation, farmers are encouraged to supplement intra-specific genetic diversity in these populations with seed collected from local forests. For some tree species, however, this approach may be inappropriate, as stands of these taxa already found on-farm may not be of local origin. Despite this issue being of importance for conservation, little information is available on the history of cultivated trees in the region, a situation that we here rectify for the important fruit tree Inga edulis. Based on nuclear SSR and chloroplast DHPLC analyses of closely geographically matched natural and planted stands at five sites, it appears that cultivated material of I. edulis is primarily of non-local origin, indicating that conservation based on new wide-scale infusions from local wild stands into farms may be inappropriate in the region. Although nuclear and chloroplast diversity were both lower in planted stands, values were still relatively high (∼80 and 70% of natural stands, respectively), indicating that when farmers plant trees, good collection practice of seed from already cultivated I. edulis should be an effective means for ensuring long-term conservation on farms.     

Phenomorphology and Eco-morphological Characters of Rhododendron Lauroid Forests in the Western Mediterranean (Iberian Peninsula, Spain)

The evergreen broad-leaved forest of Rhododendron ponticum represents a special type of Mediterranean vegetation because of their relict nature (allegedly pre-glacial, Southern-Iberian and Pontic) and connection with Macaronesian-Atlantic flora. The findings of ecomorphological (growth forms) and phenological (phenology) studies point to characteristics typical of its relict character and its relationship with subtropical lauroid vegetation (greater forest stratification, larger leaves, high percentage of photosynthetic stems, scarce tomentosity, pre-flowering in a season different to Mediterranean species and closeness of autumn–winter flowering species). There are, however, links with typical Mediterranean vegetation (Quercus L. forests) that surrounds the Rhododendron stands, due to its adaptation to Mediterranean climate (sclerophyll leaves, plant and leaf duration, post-fire regeneration, fleshy fruit and fruit setting-seed dispersal seasonality). Within the community, different groups of plants show different adaptations to the same biotope, suggesting their distinct paleo-phytogeographical origins. The results confirm the singularity of this vegetation within the typically Mediterranean environment where it grows and its connections with other extra-Mediterranean types.