Community Forest Management in the Maya Biosphere Reserve (MBR; Petén, Guatemala) has been recognized internationally for yielding forest conservation and socioeconomic benefits. However, the effect of current timber harvesting practices on the genetic diversity of timber species populations has not previously been documented. This study assessed the effects of timber harvesting on the genetic diversity and viability of regeneration of the most commercially important timber species in the MBR: big-leaf mahogany (Swietenia macrophylla King). Trees and seeds were sampled for two consecutive years in two Forest Management Units of the Multiple Use Zone (MUZ) of the MBR: Cruce a la Colorada and Carmelita. We correlated genetic diversity parameters (as measured using nuclear microsatellites) with seed germination percentages and compared genetic diversity of adults and seeds in stands that had been affected by timber harvesting and those that had not. We found a significant correlation between seed germination percentages (81–83%) and observed heterozygosity (rho=0.27), confirming that genetic diversity is important to regeneration success. No significant differences were found in allelic richness (AR), expected and observed heterozygosity (HE and HO), or inbreeding (FIS), between adults and seeds in harvested vs. undisturbed stands; or before and after timber harvesting. We found low inbreeding levels (FIS=0.040–0.094), low biparental inbreeding (0–0.01), and high outcrossing rates (0.925–0.970) in the populations of S. macrophylla analyzed. Our study therefore provides evidence that genetic diversity in big-leaf mahogany populations was not diminished by one cutting cycle under current practices of community forest management in the MUZ of the MBR.

The potential of forest foods to address malnutrition, food insecurity and poor dietary intake is increasingly being recognized. However, most existing data presents average results of proximate analysis, overlooking the opportunities to document how forest foods contribute to nutrition, food security and dietary intake. In this study, food security was estimated using the HFIAS score while dietary intake was estimated using FFQ recalls among 720 households in and around six logging concessions in Cameroon, DR Congo and Gabon. There was a high diversity of forests foods consumed, with DR Congo (FFCS=16.2) registering the highest number. Cameroon had the highest number of food groups (HDDS=12.5) while Gabon had the highest number of food varieties (FVS=24.5). Despite a highly diverse pool of wild foods in the region, most households (82%) practicing farming on logged land suffered from food insecurity. A significant inverse correlation was observed between the HFIAS score and the FFCS (r 2 =–0.26, P=0.0002), revealing that forest foods can play a role in ensuring food security and nutrition among populations near forest concessions. The chi-square test revealed that age >46 years, and access to income from business or salaries were associated with food security. Further work is required to document how wild forest foods can contribute to improved diets among these populations, including documenting the nutrient composition of more forest foods, integrating them into regional dietary guidelines and encouraging their domestication.

Central Asia is an important center of origin for many globally valued fruit and nut tree species. Forest degradation and deforestation are cause for concern for the conservation of these valuable species, now confined to small remnant populations. Home gardens have the important function of sustaining household food consumption and income generation, and can potentially play a critical role in conserving diversity of fruit and nut trees. These systems have been very poorly documented in the scientific literature. This study contributes to filling this gap by describing the diversity of fruit and nut trees in home gardens of Kyrgyzstan, Uzbekistan, and Tajikistan, examining their dynamic flow of planting material and its sources, understanding their future prospects, and looking at significant differences between the three countries. Home gardens show a similar portfolio of the most abundant tree species (apple, apricot, walnut, pear, and plum). Although the diversity of tree species and varieties recorded is significant, small population sizes can limit future possibilities for this diversity to thrive, given the pressure on natural stands and on habitats where the preferred species are found. Furthermore, the selection of species and varieties to be planted in home gardens is increasingly influenced by market opportunities and availability of exotic material. Some of the most abundant tree species recorded are represented largely by exotic varieties (apple, pear), while others (e.g., apricot, walnut, plum) are still mainly characterized by traditional local varieties that are not formally registered. Home gardens continue to play a critical role in rural livelihoods and in national economies, and many rural inhabitants still aspire to maintain them. Thus, home gardens should be integrated in national research and extension systems and closely linked to national conservation efforts. Changes and possible declines in the diversity they host, their health status, and resilience should be carefully monitored.

Central Asia is an important center of diversity for common walnut (Juglans regia L.). We characterized the genetic diversity of 21 wild and cultivated populations across Kyrgyzstan, Tajikistan, and Uzbekistan. A complete threat assessment was performed evaluating the short-term threats from overexploitation, overgrazing, landslides, and fragmentation as well as long-term threats from climate change. Based on key indicators of genetic diversity and threat magnitude, we developed an approach to identify wild populations for priority conservation and defined appropriate measures to conserve their genetic diversity based on the specific threat magnitudes. We propose (i) ex situ conservation in areas with “severe threat level” due to climate change and (ii) in situ conservation in areas with “minor threat level” due to climate change. In addition, we suggest (iii) assisted natural regeneration in areas where “minor threat levels” from climate change coincide with “severe threat levels” from one or more short-term threats. Our research shows high levels of genetic diversity as well as high threat levels in the walnut populations examined across three countries. Overgrazing and overexploitation were identified as the two most important threats whereas climate change turned out to be of minor concern in the near future. Four out of the five populations selected for priority conservation are severely threatened: Kara-Alma (KGP3) and Sariosiyo (UZP4) by overexploitation and overgrazing, Vanj (TJP2) by landslides and fragmentation and Bostanlyk_2 (UZP2) by overexploitation. Only the Baljuvon population (TJP4) in Tajikistan shows minor threat levels in the short and long term. Thus, for all five priority populations the most appropriate conservation approach appears to be in situ conservation. Spontaneous natural regeneration should be sufficient to ensure the long-term survival of the Baljuvon population (TJP4), while for the other four priority populations assisted natural regeneration may be needed. This network of five sites represents the minimum number of conservation areas for wild walnut in the three countries that should be established to capture a significant amount of the species genetic diversity. Conservation efforts could be extended to home gardens, which are a valuable genetic reservoir for the wild diversity found in the region.

The genus Khaya includes some of the highest-value timber species in natural forests in Africa, which are under heavy exploitation pressure. Genetic identification of Khaya species is important to confirm the taxonomic classification for biodiversity conservation purposes and as a forensic tool aiding law enforcement in the fight against illegal logging. We collected samples from a total of 2222 trees belonging to five or six (depending on classification) different Khaya species (K. ivorensis, K. anthotheca/K. nyasica, K. grandifoliola, K. senegalensis, K. madagascariensis). Representative sampling was conducted over the natural ranges of all sampled Khaya species, in humid tropical forest and savanna zones. We genotyped individuals based on 101 molecular markers (67 nuclear, 11 chloroplast and 22 mitochondrial SNPs, 1 chloroplast indel). Bayesian clustering produced three main genetic groups assigning all K. ivorensis and all K. senegalensis trees, respectively, in two different clusters and all remaining individuals in a third cluster. Genetic self-assignment tests with all 101 SNPs had success rates of 97–100% for all species except for K. nyasica and K. madagascariensis, which could not be clearly distinguished from each other. A success rate for species identification nearly as high was observed using a subset of 15 highly differentiated SNPs. There was only very little evidence for hybridization among species and the vast majority (> 97%) of individuals were assigned to the same species group as identified based on morphological characters.

Molecular genetics research can benefit efforts to conserve the genetic diversity of tropical plant species. Clear and efficient procedures are needed to access DNA samples, while respecting tropical countries' and local communities' rights on genetic resource usage. The Nagoya Protocol on Access and Benefit-Sharing, which took effect in 2014, provides an opportunity to establish such procedures. However, scientists are concerned that its emphasis on monetary gains restricts research focused on scientific, societal, and environmental benefits. Despite much political and scientific debate, few concrete cases have demonstrated the practical functioning of the Nagoya Protocol. This paper describes the first application of the Protocol in Guatemala, where it was used to grant permission to a non-commercial study on gene flow in mahogany (Swietenia macrophylla King) populations in the Maya Biosphere Reserve of Peten. On the basis of this study, we discuss five strategies to enhance the application of molecular genetics to conservation biology under the Nagoya Protocol: (1) generate short and standardized procedures; (2) enable science communication; (3) cultivate a common understanding between users, providers, and potential beneficiaries; (4) involve local research and practitioner organizations; and (5) integrate participatory research. Positive societal views on the application of molecular genetics to conservation biology generate further support for work in this discipline and promote adoption of research results for the conservation of genetic diversity of tropical plant species.

Background: Humans threat the populations of tree species by overexploitation, deforestation, land use change, and climate change. We present a novel threat assessment at intraspecific level to support the conservation of genetic resources of 80 socioeconomically viable tree species in South America. In this assessment, we evaluate the threat status of Ecogeographic Range Segments (ERSs). ERSs are groups of populations of a specific species in a certain ecological zone of a particular grid cell of a species' geographic occupancy. Methods: We used species location records to determine the species distributions and species-specific ERSs. We distinguished eight threat situations to assess the risk of extirpation of the ERSs of all 80 species. These threat situations were determined by large or little tree cover, low or high human pressure, and low or high climate change impact. Available layers of tree cover and threats were used to determine the levels of fragmentation and direct human pressure. Maxent niche modelling with two Global Circulation Models helped determining climate change impact by the 2050s. Results: When all 80 species are considered, in total, 59% of the ERSs are threatened by little tree cover or high human pressure. When climate change is also considered, then 71-73% of the ERSs are threatened. When an increased risk of extirpation of populations outside protected areas is considered, then 84-86% of the ERSs are threatened. Seven species warrant special attention because all their ERSs are threatened across their whole distribution in South America: Balfourondendron riedelianum, Cariniana legalis, Dalbergia nigra, Handroanthus pulcherrimus, Pachira quintana, Prosopis flexuosa, and Prosopis pallida. Conclusions: Our results confirm the urgency to set up a regional action plan for the conservation of tree genetic resources in South America. With this threat assessment, we aim to support governments and organizations who are taking up this task.

Over the last decades agroforestry parklands in Burkina Faso have come under increasing demographic as well as climatic pressures, which are threatening indigenous tree species that contribute substantially to income generation and nutrition in rural households. Analyzing the threats as well as the species vulnerability to them is fundamental for priority setting in conservation planning. Guided by literature and local experts we selected 16 important food tree species (Acacia macrostachya, Acacia senegal, Adansonia digitata, Annona senegalensis, Balanites aegyptiaca, Bombax costatum, Boscia senegalensis, Detarium microcarpum, Lannea microcarpa, Parkia biglobosa, Sclerocarya birrea, Strychnos spinosa, Tamarindus indica, Vitellaria paradoxa, Ximenia americana, Ziziphus mauritiana) and six key threats to them (overexploitation, overgrazing, fire, cotton production, mining and climate change). We developed a species-specific and spatially explicit approach combining freely accessible datasets, species distribution models (SDMs), climate models and expert survey results to predict, at fine scale, where these threats are likely to have the greatest impact. We find that all species face serious threats throughout much of their distribution in Burkina Faso and that climate change is predicted to be the most prevalent threat in the long term, whereas overexploitation and cotton production are the most important short-term threats. Tree populations growing in areas designated as 'highly threatened' due to climate change should be used as seed sources for ex situ conservation and planting in areas where future climate is predicting suitable habitats. Assisted regeneration is suggested for populations in areas where suitable habitat under future climate conditions coincides with high threat levels due to short-term threats. In the case of Vitellaria paradoxa, we suggest collecting seed along the northern margins of its distribution and considering assisted regeneration in the central part where the current threat level is high due to overexploitation. In the same way, population-specific recommendations can be derived from the individual and combined threat maps of the other 15 food tree species. The approach can be easily transferred to other countries and can be used to analyze general and species specific threats at finer and more local as well as at broader (continental) scales in order to plan more selective and efficient conservation actions in time. The concept can be applied anywhere as long as appropriate spatial data are available as well as knowledgeable experts.

Forest genetic resources refer to the genetic variation in trees (woody perennials) of current or future value to humans. They are crucial for the well-being of people and adequate functioning of forest ecosystems, but are increasingly threatened as populations of tree species are lost or degraded as a result of human activities. The chapter looks at the diversity of benefits that are derived from forest/tree genetic resources, the state of knowledge of those resources and issues that are crucial to their sustainable use and conservation, both within and outside of forests. In particular, it considers the conservation-on-farm value of trees and how the context of landscape, land-use, agricultural/agroforestry systems, the forest/agriculture interface and socio-economic and cultural values influence use and conservation options. This is set against a background of how basic biological differences between tree species and annual/other crops influence levels and patterns of genetic diversity, their subsequent use and conservation.

Pollen and seed dispersal are key processes affecting the demographic and evolutionary dynamics of plant species and are also important considerations for the sustainable management of timber trees. Through direct and indirect genetic analyses, we studied the mating system and the extent of pollen and seed dispersal in an economically important timber species, Entandrophragma cylindricum (Meliaceae). We genotyped adult trees, seeds and saplings from a 400-ha study plot in a natural forest from East Cameroon using eight nuclear microsatellite markers. The species is mainly outcrossed (t=0.92), but seeds from the same fruit are often pollinated by the same father (correlated paternity, r(p)=0.77). An average of 4.76 effective pollen donors (N-ep) per seed tree contributes to the pollination. Seed dispersal was as extensive as pollen dispersal, with a mean dispersal distance in the study plot approaching 600m, and immigration rates from outside the plot to the central part of the plot reaching 40% for both pollen and seeds. Extensive pollen- and seed-mediated gene flow is further supported by the weak, fine-scale spatial genetic structure (Sp statistic=0.0058), corresponding to historical gene dispersal distances (sigma(g)) reaching approximately 1,500m. Using an original approach, we showed that the relatedness between mating individuals (F-ij=0.06) was higher than expected by chance, given the extent of pollen dispersal distances (expected F-ij=0.02 according to simulations). This remarkable pattern of assortative mating could be a phenomenon of potentially consequential evolutionary and management significance that deserves to be studied in other plant populations.

Enterolobium cyclocarpum is a characteristic legume tree species of seasonally dry tropical forests (SDTFs) of Mesoamerica and northern South America typically used in silvopastoral and agroforestry systems. Remaining populations of E. cyclocarpum in Colombia are severely fragmented owing to the highly degraded state of SDTF in the country, posing threats to both their in situ persistence and their usefulness as seed sources for future planting efforts. We genotyped E. cyclocarpum populations at nine sampling sites across a latitudinal gradient of SDTF in Colombia by means of eight nSSR markers to elucidate the species diversity distribution in the country. Our data suggest that a deep divide seems to have existed between Caribbean and Andean populations of E. cyclocarpum in Colombian SDTF that may date back to the last glacial maximum (~21,000 BP), or longer. However, we only found evidence of genetic differentiation between trees from the southern Cauca River valley and populations at more northern locations. All the latter populations showed signs of admixture which may be the result of human-influenced movement of germplasm, particularly after the introduction of cattle by European settlers. Most of the sampled sites showed heterozygosity scores close to Hardy–Weinberg expectations. Only the three southern-most populations displayed significantly positive values of inbreeding coefficient, potentially affecting their in situ maintenance and their use as seed sources. Based on our findings we identify priority areas for the in situ conservation of remaining E. cyclocarpum populations, and propose a strategy for sourcing of appropriate planting material for use in future tree planting efforts.

Extensive areas of the Congo Basin forest are allocated to timber concessionaires. These forests also harbour and support village populations, including indigenous Baka people, who depend on forest foods obtained directly from trees (fruits, oils and caterpillars). Most food-producing tree species are harvested by concessionaires for timber. We documented the availability and abundance of three food tree species around four villages and in two neighboring timber concessions in Cameroon. Data was used to determine the importance of timber concessions as sources of food for local people to provide a foundation for governance arrangements that consider local needs for foods from timber trees. Discussions with concessionaires revealed that some of them have voluntarily refrained from extracting timber species of interest to villagers for their nontimber products. This is either to avoid conflict with villagers, or because regulations have been promulgated to safeguard these resources. The interplay between internal village dynamics, regulations and their implementation by forest guards, and the actions of timber concessions create a complex arena for addressing rights to forest resources. This paper provides information on the accessibility and availability of multiple use timber species as a foundation for negotiations and governance arrangements between concessionaires and local communities.

AbstractObjectiveTo determine the contribution of forest foods to dietary intake and estimate their association with household food insecurity.DesignCross-sectional survey conducted among 279 households. Using a 7 d recall questionnaire, information on household food consumption was collected from women and used to determine the household dietary diversity score, food variety score and forest food consumption score (FFCS). Household Food Insecurity Access Scale (HFIAS) score was determined and Spearman rank correlation was used to establish the relationship between consumption of forest foods and HFIAS score. Women’s dietary intake was estimated from two 24 h recalls. The contribution of forest foods to women’s nutrient intakes was calculated and women’s nutrient intakes were compared with estimated average nutrient requirements.SettingRural forest-dependent households in twelve villages in eastern and southern Cameroon.SubjectsHousehold heads and their non-pregnant, non-lactating spouses.ResultsForty-seven unique forest foods were identified; of these, seventeen were consumed by 98 % of respondents over the course of one week and by 17 % of women during the two 24 h recall periods. Although forest foods contributed approximately half of women’s total daily energy intake, considerably greater contributions were made to vitamin A (93 %), Na (100 %), Fe (85 %), Zn (88 %) and Ca (89 %) intakes. Despite a highly biodiverse pool of foods, most households (83 %) suffered from high food insecurity based on the HFIAS. A significant inverse correlation was observed between the HFIAS score and the FFCS (r2=−0·169, P=0·0006), demonstrating that forest foods play an important role in ensuring food security in these forest-dependent communities.ConclusionsForest foods are widely consumed by forest-dependent communities. Given their rich nutrient content, they have potential to contribute to food and nutrition security.

Mating system and gene flow are major influencing factors of species population dynamics and evolution. These factors are often not characterized in tropical tree species, yet they constitute basic information that must be considered to implement sustainable management practices. In particular, as logging implies a reduction of the density of congeneric mates, the connectivity through pollination between individuals has to be well characterized (selfing versus outcrossing rates, distances between mates). We conducted a genetic-based analysis (using 10 nuclear microsatellites) to determine the mating system and gene flow characteristics of an emblematic timber tree species from lowland rain forests of the Congo Basin, Baillonella toxisperma (Sapotaceae). The species, which is frequently exploited for its wood and for a number of non-timber forest products, naturally occurs at low densities (ca. 0.01-0.1 individuals/ha). It is supposedly an entomophilous species whose seeds are probably dispersed by mammals. We have shown that the species presents a mixed-mating system (about 20-40% of selfing depending on analysis method). However, the comparison of inbreeding parameters among cohorts suggests that inbred individuals die between seedling and mature tree stages. The mean pollen dispersal distance was relatively low for such a low-density population species (estimated to be 690 or 777 m depending on analysis method) and, together with a low mean number of pollen donors (N-EP = 2.76), it suggests a pattern of nearest-neighbour mating where allo-pollen could be a limiting factor. However, B. toxisperma presents a relatively weak genetic structure (Sp statistic = 0.0095) indicative of long gene dispersal distance (sigma(g) = 3-5 km according to the assumed effective population density). Overall, this would indicate that gene flow occurs mainly by extensive seed dispersal in this species. These results suggest that mammals and local populations involved in the dispersal of the species play a key role by lowering biparental inbreeding effects. Sustainable population management might require assisted regeneration using unrelated planting material. (C) 2016 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.orgilicenses/by-nc-nd/4.0/).

Genetic resources determine the adaptive potential of trees and influence the long-term value of tree-planting efforts for climate change mitigation. Trees are essential components of adaptation and mitigation strategies to counter impacts of climate change. On the one hand, trees play a vital role in adaptation of landscapes and human communities to tolerate climatic changes, including hotter and drier conditions; and, on the other, expanding forest cover increases the carbon sequestration capacity of landscapes, mitigating the negative impacts of emissions. Genetic resources determine the adaptive potential of trees as well as influencing the long-term value of tree-planting efforts for mitigation purposes. Thus genetic resources of trees are critical for effective adaptation and mitigation responses to climate change. In spite of this, among natural resource managers, restoration practitioners and conservation agents, little attention is paid to the importance of forest tree genetic resources and their vulnerability to impacts of climate change if not properly managed. Genetic diversity comprises the heritable differences among individuals within a species, and forest genetic resources refers Judy Loo works for Bioversity International (Rome, Italy) as Science Domain Leader, Forest Genetic Resources and Restoration. © IO V ER SITY IN ER N A IO N A /R . K H A IL

Background: Although the importance of using local provenance planting stock for woodland production, habitat conservation and restoration remains contentious, the concept is easy to understand, attractive and easy to 'sell'. With limited information about the extent and scale of adaptive variation in native trees, discussion about suitable seed sources often emphasises "local" in a very narrow sense or within political boundaries, rather than being based on sound evidence of the scale over which adaptation occurs. Concerns exist over the actual scale (magnitude and spatial scale) of adaptation in trees and the relative dangers of incorrect seed source or restricted seed collection, leading to the establishment of trees with restricted genetic diversity and limited adaptive potential. Tree provenance and progeny field trials in many parts of the world have shown the existence of genotype by environment interaction in many tree species, but have not necessarily looked at whether this is expressed as a home site advantage (i.e. whether provenance performance is unstable across sites, and there is better performance of a local seed source).Methods/design: This review will examine the evidence for local adaptation and its scale in a number of native tree species from different trial sites across the globe (e.g. tropical, Mediterranean, temperate). These trials have been measured and in some cases results published in a range of formats. The data have, however, usually been presented in the form of which provenances grow best at which sites. The review will examine existing data (published and unpublished) in the context of the scale of local adaptation, with the results being presented in two formats: (a) relating survival, performance of provenances (classified by seed zone/provenance region of origin) to seed zone/provenance region of the planting site; (b) plotting survival, performance provenances against the distance (Euclidean/ecological) between the provenance and the trial site.

AimOur goal was to test the hypothesis that ancient humans substantially contributed to shaping the current distribution of Brazil nut (Bertholletia excelsa), an Amazonian tree species that has been important for human livelihoods since pre-Columbian times. We scrutinized the putative association between Brazil nut and Amazonian Dark Earth soils (ADE) and geometric earthworks called geoglyphs, and examined the existence of continental patterns in human footprints on Brazil nut stands.LocationAmazon Basin.MethodsWe carried out a spatially explicit meta-analysis of the variation of Brazil nut stand metrics across the Amazon Basin based on 87,617 density estimates and 488 average stand diameter assessments, and related these to previously published datasets and suitability maps of Brazil nut, ADE and geoglyphs.ResultsWe found consistently higher Brazil nut suitability scores, stand densities and average stand diameters in the vicinities of ADE than at larger distances, regardless of their position along a gradient from south-western to north-eastern Amazonia. For geoglyph sites such a pattern was only found for Brazil nut habitat suitability scores. The available data further revealed an accumulation of Brazil nut stands with increasing densities and average diameters from south-western to central and eastern Amazonia.Main conclusionsOur findings suggest that the chance of encountering Brazil nut stands bearing the marks of past human influences increases from south-western to central and eastern Amazonia. In south-western Amazonia, the regeneration of Brazil nut seems to have been controlled predominantly by natural processes, whereas in central and eastern Amazonia, anthropogenic disturbance has been more important since pre-Columbian times. However, it remains challenging to disentangle human influences on the distribution and abundance of Brazil nut from existing environmental gradients across the Amazon Basin. In general, the results of this meta-analysis bode well for the future coexistence of Brazil nut with different forms of contemporary human land use.