Management Of Plant Resources Research Articles

Enhancing tree species conservation in Burkina Faso through indigenous knowledge

Natural resources such as plant plays an important role in the livelihood of many local people in Africa. The high anthropogenic pressure on plant resources lead to their disappearance. Assessing ethnobotanical knowledge is useful for development of management and conservation of plant resources. Focusing on woody plants, our ethnobotanical investigations involved 60 randomly selected households across two Sahelian villages. Through semi-structured interviews, we meticulously assessed indigenous knowledge and perceptions related to the conservation of 41 woody plant species spanning 32 genera and 15 families.Our analysis categorized these species based on their diverse uses, encompassing food, medicine, fodder, construction, energy and art. The most dominant families reported Fabaceae and Combretaceae followed by Malvaceae. Notably, fruits, leaves, bark, and seeds emerged as the most valued plant organs.Crucially, our findings pinpointed human activities as the primary threat to species conservation, overshadowing climatic factors. We further identified key species and prioritized those in need of urgent conservation efforts. This study underscores the imperative of incorporating indigenous knowledge and perceptions into the development of effective conservation management strategies for plant resources in Sahelian zone.

The global distribution of plants used by humans.

Plants sustain human life. Understanding geographic patterns of the diversity of species used by people is thus essential for the sustainable management of plant resources. Here, we investigate the global distribution of 35,687 utilized plant species spanning 10 use categories (e.g., food, medicine, material). Our findings indicate general concordance between utilized and total plant diversity, supporting the potential for simultaneously conserving species diversity and its contributions to people. Although Indigenous lands across Mesoamerica, the Horn of Africa, and Southern Asia harbor a disproportionate diversity of utilized plants, the incidence of protected areas is negatively correlated with utilized species richness. Finding mechanisms to preserve areas containing concentrations of utilized plants and traditional knowledge must become a priority for the implementation of the Kunming-Montreal Global Biodiversity Framework.

Reconstructing formation processes at the Canary Islands indigenous site of Belmaco Cave (La Palma, Spain) through a multiproxy geoarchaeological approach

AbstractThe indigenous populations of La Palma (Canary Islands), who arrived on the island from Northwest Africa ca. 2000 years B.P., were predominantly pastoralists. Yet, many aspects of their subsistence economy such as the procurement, management, and use of wild plant resources remain largely unknown. To explore this, we studied the 600–1100‐year‐old archaeological site of Belmaco Cave, which comprises a stratified sedimentary deposit representative of a fumier. Here, we present a high‐resolution, multiproxy geoarchaeological study combining soil micromorphology, lipid biomarker analysis, X‐ray diffraction, μ‐X‐ray diffraction, μ‐X‐ray fluorescence, Fourier transform infrared spectroscopy, and μ‐Fourier transform infrared spectroscopy, to characterize formation processes and explore plant sources. Recurrent goat/sheep habitation and maintenance activities are represented by interstratified layers of unburned dung, charcoal‐rich sediment, and dung ash. Lipid biomarker data show a herd diet mainly composed of herbaceous plants, which is key to understanding the mobility of indigenous shepherds. Our results also revealed an unusual suite of authigenic minerals including hazenite, aragonite, and sylvite, possibly formed through diagenetic processes involving interaction between ash, dung, urine, volcanogenic components, and bacterial activity, coupled with arid and alkaline conditions. Our study shows the potential of a multiproxy approach to a fumier deposit in a volcanogenic sedimentary context.

Plant diversity patterns along an elevation gradient: the relative impact of environmental and spatial variation on plant diversity and assembly in arid and semi-arid regions

The spatial distribution pattern of species diversity and its driving variables are essential to understanding how biodiversity will respond to the threat of future climatic instability. This study examines how the alpha and beta diversity indices vary along the elevation gradient and which factors are more responsible for arid and semi-arid plant diversity and community assembly. There were 121 species from 90 genera and 42 families found at elevations ranging from 1,200 to 2,600 m within the Ningxia Helan Mountain National Nature Reserve in China. These were primarily shrubs and herbs with characteristics adapted to extreme temperatures. The diversity of both the shrub layer and the herb layer was highest at mid-elevation, underscoring the importance of protecting mid-elevation ecosystems. Climatic distance and topographic distance were more influential than spatial distance in driving the species composition change of shrubs and herbs. In the herb layer, climatic, topographic, and spatial factors contributed more to community assembly than shrub communities. In this case, improving the environment in the community or introducing herbs could help the restoration of these places. These findings provide insight into biogeographic patterns, biodiversity growth mechanisms, and community formation processes. Moreover, it can improve projections of climate change within and across ecosystems and provide the scientific basis for the use and management of plant resources in arid and semi-arid regions.

Characterizing the landscape of plant science careers in the United States I: Government and private sector perspectives

Societal Impact StatementHumans are dependent upon plants for oxygen, food, textiles, and medicines. Climate change and deforestation represent serious threats to our planet, causing significant disruptions to our ability to access and utilize these plant resources; this makes a botanically literate workforce and plant science careers more important than ever. Unfortunately, the current state of botanical career opportunities and training programs in the United States remains unclear. This study focuses on the current employment trends of government and private sector botanists and what skills future plant scientists will need to be successful in these careers.Summary Plant science plays a crucial role in our society and in ongoing efforts to address many global challenges, including food insecurity and climate change. Yet, despite a predicted increase in plant science career opportunities in the United States, the botanical career landscape outside of academia is not well understood. To further our understanding of the training required for non‐academic botanical careers, the botanical sub‐disciplines used on the job, and career challenges faced by plant scientists, we surveyed 61 scientists working in government and 59 scientists working in the private sector in the United States. In both career sectors, > 80% of survey participants reported recent hires at the bachelor's degree level. New personnel with master's degrees were more commonly reported in the government sector (95%) than in the private sector (69%). Most plant scientists working in government reported a focus on plant ecology and resource management. By contrast, most industry/non‐profit work involved horticulture and biotechnology, with some specific skills spanning both sectors. Notably, one prediction made nearly a decade ago appears to be manifesting: plant scientists seem to be retiring more quickly than they are being replaced. Survey respondents reported that attempts to hire full‐time staff are met with obstacles, including insufficient funding. Plant science professionals in both career sectors emphasized their routine use of botanical skills developed as students, highlighting the need for effective training at the undergraduate level. We discuss the implications of these findings and present several recommendations for preparing future generations of plant scientists and increasing the scientific community's botanical capacity.

Assessing plant diversity change in logged and unlogged dense semi-deciduous production forest of eastern Cameroon

This study was carried out in the dense semi-deciduous production forest of East Cameroon. The objective of this work of this study was to provide comparative floristic knowledge that can serve as a basis for the planning and sustainable management of ligneous plant resources in Communal Forests before and after logging. Sampling was done in unlogged and logged forest. Data collection was carried out using the linear transects subdivided into 10 plots of 25 m × 20 m (500 m2) with an equidistance of 225 m for the inventory of all trees with dbh ≥10 cm installed measured at 1.3 m above ground level. Nested quadrats 5 m × 5 m, oriented south-west and north-east were set up in each plot for the counting and identification of all individuals with a diameter less than 10 cm. The analysis of inventory data showed that the floristic composition was higher in the unlogged forest. The individuals were more evenly distributed in the logged (Pielou's equitability index = 0.83) than in the unlogged forest. The study of the functional spectra showed that the flora of the two forest types was dominated by Guinean-Congolese species (67.57% in the unlogged forest and 63.07% in the logged forest) and Phanerophytes, particularly Mesophanerophytes. The dominance of sarcochorous species reveals that the main mode of dissemination in this forest is zoochory, particularly endozoochory. The presence of pleochroic species in the logged forest reveals the importance of dissemination by water in the environment. The plants surveyed were divided into five plant assemblages (three for logged forest and two for unlogged forest) based on ecological parameters. The findings of this study suggest that forest management which combines assisted natural regeneration with the natural process of secondary succession facilitates the reconstitution of the vegetation cover and, by extension, the conservation of biodiversity in post-logging forest concessions.

Sacred Grove as A Tribal Ethics Of Plant Resource Management

Sacred Grove as A Tribal Ethics Of Plant Resource Management

DIVERSITY OF WILD MEDICINAL PLANTS IN THE VEGETABLE CULTIVATION AREAS IN THUONG TIN DISTRICT, HANOI CITY

Evaluation of the diversity of wild medicinal herbs contributes to creating the basis for the effective management, exploitation, and usage of medicinal plant resources in ecosystems. This study has listed 170 species of wild plants belonging to 119 genera, 50 families, 28 orders, and 2 phyla, Pteridophyta, and Magnoliophyta with medicinal value. Whole plants or up to 10 parts of local wild medicinal plants are used in the prevention and treatment of 20 common diseases.

Effect of freshwater on plant species diversity and interspecific associations in coastal wetlands invaded by Spartina alterniflora.

Plant invasions in coastal wetlands lead to the degradation of native vegetation; the introduction of freshwater in coastal wetlands would prevent the spread of invasive plants and facilitate the restoration of native vegetation. In this study, we evaluated the effects of freshwater on plant communities in the coastal wetlands of Yancheng, China, invaded by Spartina alterniflora Loisel. Two field investigations were conducted in 2008 and 2018 before and after the introduction of freshwater (started in 2011). The characteristics of plant communities were subjected to hierarchical cluster analysis and compared using several diversity indices. In addition, differences in habitat community composition and interspecific relationships of dominant species were analyzed. The results showed that S. alterniflora reduced the overall species diversity in the region. Plant species diversity increased after freshwater was introduced into the study site when compared to the areas without freshwater introduction. The introduction of freshwater caused a shift often changes in the interspecific relationships between Suaeda salsa (L.) Pall. and other species. The intensified invasion of S. alterniflora changed the interspecific relationship of native halophytes from negative to positive. Although freshwater effectively inhibited further invasion of S. alterniflora, it also increased the risk of expansion of the glycophytes in the community. The results of this study highlight the need for early intervention for restoration of coastal wetlands, preservation of biodiversity, and management of plant resources.

Are degraded karst tiankengs coupled with microclimatic underground forests the refugia of surface flora? Evidence from China’s Yunnan

Karst tiankengs, as one of the most magnificent negative topographies, are capable of forming a bank for species diversity conservation easily. More than 300 karst tiankengs have been discovered and identified worldwide. Given its treacherous terrain, although original karst tiankeng were identified as species refuges, the broader distribution of degraded karst tiankeng has not been systematically studied. Our study area comprised the degraded karst tiankeng cluster immersed in the fragmented karst forests of Yunnan, China. Fifty-eight plant samples were selected from karst tiankengs and surface. We compared species composition, and analyzed diversity indices and similarity coefficients to verify the isolation effect of karst tiankengs on floras. The results indicated that: (1) In the degraded karst tiankeng, there were 24 families, 37 genera and 48 species in the tree layer and 27 families, 43 genera and 49 species in the shrub layer. Outside the degraded karst tiankengs, 20 families, 31 genera and 39 species were in the tree layer, and the shrub layer included 26 families, 44 genera and 55 species. (2) The species composition reached significant differences within and outside degraded karst tiankeng (p < 0.05) based on the analysis of variance (ANOVA). (3) In the degraded karst tiankeng, species richness/diversity in trees were higher than those in the shrub layer, while at the surface, shrubs had higher richness and lower diversity than trees by Alpha-diversity index. And for Beta-diversity index, species similarity among degraded karst tiankengs (0.215) was extremely dissimilar, which was even lower than the contrast within and outside the degraded karst tiankengs (0.272). (4) Shared species ranged from 1 to 5 among the four habitats, with high variability in plant species across the habitat matrices. Through a comparative analysis of systematic biodiversity methods, we found that the degraded karst tiankengs, an independent type of karst tiankeng, are the unreported refugia. Species records in degraded karst tiankeng cluster will contribute to plant diversity conservation and resource management, and to the linkage with broader China’s karst floras. Karst tiankeng botanical habitats possess not only biodiversity value for in situ conservation, but will further support the ecological recovery of surface flora. While its mechanism needs to be further revealed.

Vegetation analysis and environmental indicators of an arid tropical forest ecosystem of Pakistan

Vegetation composition and/or plant species co-existence is influenced by the environmental variations in any region. The ecological knowledge and order of importance of selected environmental variations is important in conservation and management of plant resources. Based on relevant knowledge gap, the study area of district Jhelum, Pakistan lying in an arid-tropical zone was selected to explore the vegetation types and their driving environmental factors by using latest multivariate statistical approaches. For this, the entire district was ecologically explored to collect the natural wild vegetation and environmental data from January 2018 to December 2020. The study area was partitioned into 171 grids (5 × 5 km2). In each grid, three sites were randomly selected (i.e. 513 samples), and subsequently-nine plots were laid at each sampling site (i.e. 1539 plots). Different statistical tests including Monte Carlo permutation test, Indicator Species Analysis (ISA), hierarchical classification, ordination, and variation partitioning were applied to seek the potential number of vegetation types, plant species composition, classification of the studied samples, order of importance of the considered predictors and groups of environmental variables respectively. The findings of this study indicated that all the documented 291 plant species belong to five statistically significant (p < 0.05) plant communities. Out of thirty (30) considered environmental variables, canonical correspondence analysis suggested the significant role of distance from the river, altitude, latitude, slope, temperature, rainfall, distance from the cropland, grazing and deforestation pressure, and soil pollutants including chromium, arsenic and nickel concentrations. Similarly, plant diversity patterns were found strongly associated with the selected local environmental conditions. This study concluded that distance from the river (a potential leading proxy of ground water table depth) is relatively more important than the rainfall variability in this tropical arid area. Hence, the relative proportion of xerophytic plant species was found higher in the western parts compared to eastern parts adjoining the river Jhelum. Anthropogenic disturbances and potentially toxic metals were found disrupting the normal ecosystem functioning at the local scale in this arid tropical region, and need immediate attention to save the valuable local biodiversity.

신석기시대 뗀돌칼과 생업활동

The purpose of this article is to approach Low-Level food Production in Neolithic era by using Lithic knife Tool which has not been focused so far.&#x0D; Low-Level food Production stage is interpreted as an economic activity for subsistence, which could manage and utilize plant resources added to established food gathering economics, that is, the early stage of farming.&#x0D; However, Neolithic era in Korean peninsular do not have enough archeological evidence for Low-Level food Production stage because grain analyzing in Neolithic era has not been fully made in all the remains in that period. To make up for this, mutual approach in truly important thorough the stone tools for subsistence.&#x0D; Especially, the middle western area which adopted farming for the first time does not have enough analyzing information for grain respectively. Therefore, the approach through the stone tools for subsistence is absolutely needed. Because of this, well- known Amsadong village remains were chosen.&#x0D; The main trait of the Neolithic Lithic knife Tool based on analyzing data is that firstly it is a small part of all the unearthed items. Second, it departs from the standard pattern. Third, Lithic knife Tool is likely to be produced during by using width flake in the process of making a large-scale item rather than is made through a systematic process. Lithic knife Tool is likely to be made with natural sharp blade from width flake. This kind of trait has been shown in Lithic knife Tool items in Korean peninsular.&#x0D; Fourth, Lithic knife Tool in Neolithic era is excavated mainly from alluvion areas and unearthed items increased as the late Neolithic ear came. Fifth, alluvion remains excavated with grain has Lithic knife Tool. It tells us that we could see plant resources and Lithic knife Tool used as a harvesting tool also increased in the remains as it goes to the late Neolithic era.&#x0D; Despite the fact that grain analyzing evidence is not fully gathered yet, until now, Amsadong site is one of the major sites which shows harvest, management and utilization of plant resources by using Lithic knife Tool remains.&#x0D; This means that in the bronze age considered as an agrarian society, a standardized Stone Harvesting Knives was used as a exclusive tool for harvesting plant as food resource but at Amsadong site in Neolithic period considered as a low-level food production stage, exclusive tool as a tool for gathering food might not be used. Instead, it might be possible that width flake with naturally made sharp blade in the process of making large tools occurred sometimes and it was used as a tool for plant food gathering.

Impacts of the Exploitation of Rock Models on Phytodiversity in the Agbelouve Township and Its Surroundings

The exploitation of rocky outcrops is increasing and leading to the loss of biodiversity in the canton of Agbélouvé and its surroundings. This study aims to assess the impact of the exploitation of these rocks on the flora and vegetation, in order to contribute to the sustainable management of plant resources. It is based on floristic inventories of the exploitation sites and off-site. The collected data was processed by the Excel 2016 spreadsheet, and software XLSTAT 2008. The results of this research show that this activity is at the origin of the destruction of the vegetation cover and the modification of the topographic landscape. 234 species were recorded in 96 surveys, including 95 species belonging to 41 families on the exploitation sites, compared to 139 species belonging to 51 families off-site. The Shannon diversity indexes are 1.86 and 2 respectively on and off sites. Pielou's equitability index is 0.94 on the exploitation sites and 0.93 off-site. The analysis of the biological spectrum shows the predominance of phanerophytes (60.76%) off sites against (37%) therophytes on the exploitation sites. The analysis of the phytogeographical spectrum indicates the predominance of Afro-tropical species on the two sites explored. Faced with the negative impacts of the exploitation of the rock formations on the vegetation, it is necessary to take measures for the restoration of the exploitation sites.

Floristic analysis of Vascular plants in Sanzhou Island, Zhuhai, China

The uninhabited island in Guangdong is rich in vascular plant flora. In order to enrich the understanding of the zonal vegetation, a comprehensive survey of the plant resources of Sanzhou Island was carried out by using the survey method of the combination of sample line method and quadrat method. The vegetation types, floristic composition of vascular plants and the distribution types of families, genera and species were analyzed. The natural vegetation of Sanzhou Island could be divided into three types: coastal semi-mangrove, evergreen shrub and evergreen seasonal rainforest. The results showed that there were 68 species of vascular plants in 39 families, 62 genera. There were 4 families, 4 genera and 5 species of pteridophytes, accounting for 10.26%, 6.45% and 7.35% of the vascular plants; 63 species of angiosperms, 58 genera and 35 families, accounting for 89.74%, 93.55% and 92.65% of the vascular plants in the island. The floristic composition of the island showed obvious tropical nature. The main flora of the island was composed of 4 distribution types: pantropic, old world tropical, tropical Asia to tropical Australasia and tropical Asia. It showed the floristic components were diverse with strong adaptability which was suitable for the poor soil and harsh environment of the island. This study could provide a theoretical basis for the protection, development and management of plant resources in Sanzhou Island.

Relational values and management of plant resources in two communities in a highly biodiverse area in western Mexico

Relational values and management of plant resources in two communities in a highly biodiverse area in western Mexico

An annotated checklist of the vascular plants of Taita Hills, Eastern Arc Mountain.

Taita Hills forests are an ecological island within the Tsavo plains and are the northern-most part of the Eastern Arc Mountains in southeast Kenya. They are highly fragmented forests embedded in a mosaic of human settlements and farms on the slopes and hilltops. Despite their intensive degradation, they exhibit a high degree of plant diversity and endemism, and therefore are regarded as a biodiversity hotspot. In spite of their distinct importance to the biodiversity of the region as well as supporting the livelihoods of the surrounding communities, floristic studies in these hills have been finite. Through repetitive floral expeditions, herbarium records from the East African Herbarium (EA), Global Biodiversity Information (GBIF), and the Integrated Digitized Biocollections (iDigbio) databases, as well as plant lists from literature and monographs, we provide a comprehensive checklist of 1594 taxa representing 159 families, 709 genera, 1530 species, 39 subspecies, 27 varieties, and 2 hybrids. Out of these, 75 are endemic or near-endemic, 59 are exotic, and 83 are listed as either endangered or near endangered as evaluated in the IUCN Redlist. Zehneriatuberifera G.W.Hu & Q.F.Wang, a new species to science, which has previously been described, was also discovered from the Ngangao forest fragment. Information on the habit(s), habitat(s), and altitudinal range of each taxon is provided in this study. This checklist is an updated inventory of the vascular plants of the Taita Hills. It confirms the high plant diversity of the hills and provides a clear baseline for strategic conservation and sustainable management of plant resources and diversity under the Convention on Biological Diversity (CBD).

Comparação socioambiental em sistemas produtivos agrícolas indígenas: Tontotuna, Totoró-Colômbia e Tsotsil, Chamula-México

Abstract A comparison of the conservation practices associated with the management of the family agricultural production system called the Trau Misak garden and the Patchocona garden is presented. in the indigenous peoples of the Tontotuna Reservation, Municipality of Totoró-Cauca-Colombia and the Tsotsil people, Municipality of Chamula-Chiapas-México, respectively. The methodology was framed in hermeneutics and was based on ethnobotany, interrelating the axes of time, space and culture. Given the holistic and complex nature of this research, ethnography and participatory action research were used with descriptive techniques for the dynamics of use and management of plant resources in Trau Misak and Patchocona’. The results present the comparative transformation strategies that are generated and used in Trau Misak and Patchocona ‘, strengthening the identity of each indigenous people, facing the problems of survival and contributing to the reduction of hunger, by laying the foundations for food security.

Tropical Important Plant Areas, plant species richness and conservation in the British Virgin Islands

The global loss of biodiversity is a pressing and urgent issue and halting loss is the focus of many international agreements and targets. However, data on species distribution, threats and protection are limited and sometimes lacking in many parts of the world. The British Virgin Islands (BVI), part of the Puerto Rican Bank Floristic Region in the Caribbean Biodiversity Hotspot, is rich in plant diversity and regional endemism. Despite the established network of National Parks in the BVI and decades of botanical data from international collaboration between the Royal Botanic Gardens, Kew and the National Parks Trust of the Virgin Islands, there was a need for consolidated data on species distribution across the archipelago and national lists for threatened and rare plants of conservation concern. The process of identifying the network of 18 Tropical Important Plant Areas (TIPAs) in the BVI, completed in 2018, delivered national lists and accurate data for all 35 Species of Conservation Concern. These data (3688 georeferenced records) are analysed here to reveal species distribution across the archipelago, within the TIPAs network and the National Parks System. The TIPAs network contained all 35 Species of Conservation Concern and 91% of all the records, as expected. Ten out of the 21 National Parks had one or more of the species present. Most species occur across the archipelago, while some are restricted range and/or endemics. These new data will help management of plant conservation efforts and resources in the BVI, contributing to the revision of the Protected Areas System Plan and local environmental policies and have relevance to the wider Caribbean Region.

The Contributions of the Patient Protection and Affordable Care Act (PPACA) on Reducing Health Disparity in the United States: The Case of Louisiana

In Ethiopia, traditional medicine based mainly on medicinal plants, has been used for centuries for the treatment of human and animal health problems. The objective of this study was to document medicinal plants used to treat human and domestic animals ailments as well as the associate indigenous knowledge and conservation methods in Raya Alamata District in Northern Ethiopia. Ethno-botanical data were collected through semi-structured interviews, guided field walks, group discussions, field observations, preference ranking, paired comparison and direct matrix. The data were analyzed by descriptive statistics, informant consensus factor, and various ranking methods. Local communities heavily depend on traditional medicinal plants and associated knowledge for treating human and livestock ailments. However, medicinal plants and the associated knowledge are eroding mainly due to agricultural expansion, deforestation and land degradation for seeking new agricultural lands and firewood, as well as the unsustainable practices of plant or plant part sampling for medicinal values. Thus, public awareness needs to be raised among local communities and all other stakeholders on sustainable utilization and management of medicinal plant resources and the associated knowledge. On the top of that, ex-situ and in-situ conservation measures should be given particular attentions. Keywords : Medicinal plants, indigenous knowledge, human ailment, Ethiopia DOI: 10.7176/PPAR/11-9-04 Publication date: May 31 st 2021

Molecular techniques in the assessment of genetic relationships between populations of Consolida (Ranunculaceae)

Genetic diversity studies are essential to understand the conservation and management of plant resources in any environment. The genus Consolida (DC.) Gray (Ranuculaceae) belongs to tribe Delphinieae. It comprises approximately 52 species, including the members of the genus Aconitella Spach. No detailed Random Amplified Polymorphic DNA (RAPD) studies were conducted to study Consolida genetic diversity. Therefore, we collected and analyzed 19 species from 12 provinces of regions. Overall, one hundred and twenty-seven plant specimens were collected. We showed significant differences in quantitative morphological characters in plant species. Unweighted pair group method with arithmetic mean and principal component analysis (PCA) divided Consolida species into two groups. All primers produced polymorphic amplicons though the extent of polymorphism varied with each primer. The primer OPA-06 was found to be most powerful and efficient as it generated a total of 24 bands of which 24 were polymorphic. The Mantel test showed correlation (r = 0.34, p=0.0002) between genetic and geographical distances. We reported high genetic diversity, which clearly shows the Consolida species can adapt to changing environments since high genetic diversity is linked to species adaptability. Present results highlighted the utility of RAPD markers and morphometry methods to investigate genetic diversity in Consolida species. Our aims were 1) to assess genetic diversity among Consolida species 2) is there a correlation between species genetic and geographical distance? 3) Genetic structure of populations and taxa.