Woody Plant Species Diversity Research Articles

Long-term surveys of ungulates' effects on tree and shrub species in mountainous forests -outcomes and potential limits.

Ungulate herbivory might induce different effects on the diversity and growth of trees and shrubs. The density, distribution, and the species of ungulates as well as plant communities' composition and other factors determine whether ungulate herbivory promotes or limits plants' diversity and growth. The impacts of ungulates on woody plants are commonly surveyed with exclosure-control approaches. In practice, such surveys frequently only cover short periods of time, addressing immediate management needs. Long-term surveys, documenting lasting effects of ungulate herbivory, are highly needed, but still rare. However, the general transferability of outcomes of long-term surveys might be limited due to different disturbing factors. This study addresses two basic aspects of long-term monitoring in mountainous forests, based on a unique 30-year data set: (1) Possible long-term effects of herbivores on forest vegetation (e.g., species/structural diversity of woody plants) and (2) potential differences between short-term and long-term surveys in terms of height growth patterns. In our study, diversity of woody plant species showed great variability with no significant impact of ungulate herbivory. The presence of ungulates had a significantly negative effect on the vertical structural diversity and growth of trees. Due to the slower growth on control plots, it took trees longer to reach a 160 cm height-threshold with their terminal shoots than on exclosure plots. Our long-term control-exclosure data set indicated that long-term survey data indeed might differ from growth patterns represented by short-term surveys. This can be induced by several factors, like site-specific growth patterns of trees, occurrences of natural abiotic disturbances that influence the functional life of exclosures, and others.

Farm management and landscape context shape plant diversity at wetland edges in the Prairie Pothole Region of Canada.

Evaluating the impacts of farming systems on biodiversity is increasingly important given the need to stem biodiversity loss, decrease fossil fuel dependency, and maintain ecosystem services benefiting farmers. We recorded woody and herbaceous plant species diversity, composition, and abundance in 43 wetland-adjacent prairie remnants beside crop fields managed using conventional, minimum tillage, organic, or perennial cover (wildlife-friendly) land management in the Prairie Pothole Region. We used a hierarchical framework to estimate diversity at regional and local scales (gamma, alpha), and how these are related through species turnover (beta diversity). We tested the expectation that gamma richness/evenness and beta diversity of all plants would be higher in remnants adjacent to perennial cover and organic fields than in conventional and minimum tillage fields. We expected the same findings for plants providing ecosystem services (bee-pollinated species) and disservices (introduced species). We predicted similar relative effects of land management on alpha diversity, but with the expectation that the benefits of organic farming would decrease with increasing grassland in surrounding landscapes. Gamma richness and evenness of all plants were highest for perennial cover, followed by minimum tillage, organic, and conventional sites. Bee-pollinated species followed a similar pattern for richness, but for evenness organic farming came second, after perennial cover sites, followed by minimum tillage and conventional. For introduced species, organic sites had the highest gamma richness and evenness. Grassland amount moderated the effect of land management type on all plants and bee-pollinated plant richness, but not as expected. The richness of organic sites increased with the amount of grassland in the surrounding landscape. Conversely, for conventional sites, richness increased as the amount of grassland in the landscape declined. Our results are consistent with the expectation that adopting wildlife-friendly land management practices can benefit biodiversity at regional and local scales, in particular the use of perennial cover to benefit plant diversity at regional scales. At more local extents, organic farming increased plant richness, but only when sufficient grassland was available in the surrounding landscape; organic farms also had the highest beta diversity for all plants and bee-pollinated plants. Maintaining native cover in agroecosystems, in addition to low-intensity farming practices, could sustain plant biodiversity and facilitate important ecosystem services.

Composition and diversity of woody plant species in agro-ecosystems of Uluguru Mountains, Tanzania

Woody plant species are important components of agro-ecosystems that determine their productivity and biodiversity conservation in tropical mountain landscapes. This study investigates woody plant species composition and diversity through simple random sampling of sixty (10 × 10 m) plots in crop fields, hedgerows, and homegardens at Uluguru Mountains, Morogoro, Tanzania. In total, 85 woody plant species, representing 82 genera and 40 families were recorded. The most species-rich families were Proteaceae (with 323 individuals), Lauraceae (205), and Meliaceae (185). Among the woody plant species, Grevillea robusta (Proteaceae) showed the highest importance value index of 41% across different agro-ecosystem types. Shannon (1.87), Simpson (0.82), and evenness (0.91) diversity indices were highest in hedgerows compared to other agro-ecosystems. Hedgerows recorded the maximum richness, followed by homegardens and lastly crop fields. Present agro-ecosystems should be promoted to enhance the restoration and conservation of agro-biodiversity in mountain landscapes.

Diversity, preference, and conservation priority of woody plant species in coffee agroforestry system in southwest Ethiopia

Diversity, preference, and conservation priority of woody plant species in coffee agroforestry system in southwest Ethiopia

Floristic Composition, Diversity, and Regeneration of Woody Plant Species of Dabal Forest in Southeastern Ethiopia: Implication for Conservation.

Floristic composition, population structure, and regeneration status of woody species of Dabal forest found in East Hararghe zone of Oromia Regional State, Ethiopia, were studied. Vegetation data were obtained from 52 main plots of 20 × 20 m for mature woody species and 5 subplots of 5 × 5 m for seedlings and saplings. Density and dbh of each live woody plant species found in each sample plot were recorded. Frequency, basal area, importance value, and Shannon-Wiener diversity indices were also computed. Totally 59 woody plant species distributed in 33 families were documented. Of these, 45.80, 44.10, and 5.08% were shrubs, trees, and lianas, respectively. Species diversity and evenness indices were 3.56 and 0.87, respectively. Stem count of all woody species was 3379 stems ha-1. Out of this, 44.6, 30.8, and 24.59% were seedlings (dbh <3.5 cm), saplings (dbh between 3.5 and 10 cm), and mature (dbh >10 cm) individuals, respectively. Total basal area of all individuals with dbh ≥3.5 cm was 29.88 m2 ha-1. Juniperus procera, Cupressus lusitanica, Eucalyptus globulus, Afrocarpus falcatus, Eucalyptus camaldulensis, Myrsine africana, Maytenus undata, Hagenia abyssinica, Ekebergia capensis, and Cordia africana were species with top ten IVI. Most of these species were top densest, dominant, and frequent. Analysis of population structure based on pooled densities of all species in each dbh class showed that density of seedling > sapling > mature individuals, signifying healthy population structure with good natural regeneration potential. On individual basis, however, 35.6 and 8.5% of species showed fair and poor regeneration statuses, respectively, that deserve attention for conservation.

Species diversity and community assembly of woody plants at different life history stages during the natural restoration of degraded karst forests

Species diversity and community assembly of woody plants at different life history stages during the natural restoration of degraded karst forests

Grazing intensity effects on rangeland condition and tree diversity in Afar, northeastern Ethiopia

This study assessed the effects of different grazing pressures (light, moderate and heavy) on rangeland condition and woody species diversity in northeastern Ethiopia. Rangeland condition was analyzed using common protocols for the assessment of semi-arid rangelands. A total of 4 grasses, 5 herbs, 1 sedge and 14 tree and/or shrub species were identified. Results show that grazing intensity had detrimental effects on condition of the rangeland, and caused undesirable changes in herbaceous species composition. The contribution of undesirable plants to herbaceous aboveground biomass was particularly high (40 %) compared to the 30 % contributed by highly desirable species. Nearly all measures of range condition were negatively affected by grazing. Grass composition, number of seedlings and age distribution, basal and litter cover, soil erosion and compaction decreased significantly as grazing intensity increased. Species richness and diversity (Hill numbers) of woody plants were reduced significantly by grazing. The overall condition of the rangeland was generally poor. The pastoralists perceived that recurring droughts, heavy continuous grazing and inappropriate management interventions, and bush encroachment were the main contributing factors that led to overgrazing and rangeland deterioration in the area. In conclusion, our study shows that livestock grazing in northeastern Ethiopia degrade range condition and woody vegetation, and its effects are sever under moderate and heavy grazing. Management measures such as resting of the rangelands preferably with stock exclusions for 6–12 months or protecting heavily degraded or sensitive areas from livestock activity and reseeding may be the viable options to mitigate declines in range conditions.

Microtopographic Variation in Biomass and Diversity of Living and Dead Wood in a Forest in Dongling Mountains, China

Habitat heterogeneity caused by topographic variations at the local scale is the environmental basis for the establishment and evolution of biodiversity and biomass patterns. The similarities and distinctions between the effects of microtopographic variables on living wood (LWD) and dead wood (CWD) remain unknown. In the present study, the response mechanisms of biomass and species diversity patterns of living wood (LWD) and coarse woody debris (CWD) to microtopographic parameters were quantified in a warm temperate secondary forest located in Dongling Mountain, China. This quantification was achieved using a generalized additive model on a completely mapped 20-hectare permanent plot. The evaluation of biomass and species diversity of woody plants was carried out by utilizing the total basal area of all individuals and the species richness within each 20 m × 20 m quadrat as a standard. The results indicate that there are notable disparities in the influence of microtopographic elements on the LWD and CWD. In the case of LWD, microtopography accounts for 22.90% of the variation in total basal area, with convexity making a greater relative contribution than elevation, slope, and aspect. Additionally, microtopography explains 46.20% of the variation in species richness, with aspect making a greater relative contribution than elevation, convexity, and slope. Nevertheless, the influence of microtopography on CWD may only account for a deviation of 10.20% in the total basal area and 4.95% in the species richness; aspect and slope have been identified as the primary drivers in this regard. The inclusion of microtopographic factors in the model resulted in a 23.10% increase in the explanatory deviations of LWD biomass and an 8.70% increase in the explanatory deviations of CWD biomass. The findings suggest that topographic considerations have a greater impact on the biomass distribution of LWD compared to that of CWD. Conversely, the biomass of CWD is more influenced by the species richness. The presence of microtopography plays a vital role in determining the spatial distribution of species and biomass at local scales, reflecting the multiple response mechanisms and growth strategies of vegetation in response to redistribution in water, soil, and light.

Species diversity and vegetation structure of woody plants in regenerating Juniperus forest replacing Eucalyptus in the conservation area of Gullele Botanic Garden, Addis Ababa, Ethiopia

The Gullele Botanic Garden (GBG) adjoins the north-western limit of the city of Addis Ababa, capital of Ethiopia. The floristic composition, species diversity and vegetative structure of the woody plant species in the conservation area of the garden are presented from 81 plots (20 m x 20 m). A total of 104 woody plant species (90% indigenous, the rest planted or naturalised) of 83 genera and 47 families were recorded. The dominant families were Fabaceae and Asteraceae. The number of individuals of the most dominant species, Juniperus procera, decreases with increasing DBH and height class, which indicates a good and healthy reproduction potential of the species in the conservation area. No statistically meaningful plant communities could be identified in the conservation area. Many of the species present in the dry forests of the central Ethiopian plateau occur in GBG. The species richness appears to be relatively high in comparison with what other researchers have found in natural forests on the highland plateau; 87 native woody species (of which 11 are planted) in GBG, 57-97 (cumulatively 127) in Wof-Washa, 32-85 (cumulatively 113) in Menagesha and 41-77 (cumulatively 81) in Chilimo, 34-67 (cumulatively 69) in Entoto, though the definitions for woody species have varied between studies. Clustering on the floristic data gives four partly overlapping clusters with the lowest p-values for indicator species, but the distribution of the plots on clusters changes notably if information on Eucalyptus is in- or excluded. Ordination graphs with partly overlapping groups of species are presented. The findings in this paper can serve as a baseline to follow the regeneration of the conservation area towards natural forest. This is needed for future management and sustainable utilization of the forest species at local and national levels.

Island biogeography of birds in the South West Pacific: Direct and indirect effects of physical geography and co‐occurring vegetation

AbstractAimThe distribution of birds among islands is thought to be regulated by island physical geography (i.e. island area, isolation and latitude). In contrast, work on continents indicates that bird diversity is often regulated by plant diversity. Consequently, the (statistical) direct and indirect effects of physical geography on island bird distribution are poorly understood. We investigated the relative roles of physical geography and vegetation in determining island bird diversity in the South West Pacific at two taxonomic scales of resolution: total bird diversity and bird diversity within functional guilds.LocationEleven archipelagos in the South West Pacific.TaxonLand birds.MethodsWe created a dataset characterising total and functional guild diversity for land birds and seed plants (i.e. Spermatophytes) among archipelagos. We then used mediation analysis to disentangle the direct and indirect (i.e. mediated) effects of physical geography and vegetation on bird diversity.ResultsOn a broad taxonomic scale, total bird diversity was directly determined by total plant diversity, not the area, isolation or latitude of islands. On a fine taxonomic scale results differed between functional guilds. The diversity of herbivorous and frugivorous birds was directly determined by physical geography rather than plant total and trait diversity. Woody and herbaceous plant species diversity mediated the effect of physical geography on forest‐dwelling, above ground nesting and ground nesting bird diversity. Granivorous, nectarivorous and grassland‐dwelling bird diversities were unrelated to both physical geography and herbaceous plant diversity.Main ConclusionsPhysical geography and vegetation can have both direct and indirect effects on island bird diversity. Furthermore, relationships between physical geography, vegetation and bird diversity can vary markedly among functional guilds.

Woody species diversity and carbon stock potentials in homegarden agroforestry and other land use systems, northern Ethiopia

Homegarden agroforestry (HGAF) provides wider ecosystem services in the agricultural landscapes in the tropics. However, the potentials of the homegardens for floristic species conservation and climate change mitigation were less empahsized. The present study was designed to investigate woody species diversity, carbon stock, and the relationships between woody plant species and carbon stock in the HGAF and other land use types. Three land use types were purposively selected, totalling 60 nested sample plots. The stand structure and woody plant species diversity were determined. Biomass carbon stocks were estimated employing appropriate allometric equations. Soil Organic Carbon (SOC) stocks (at 0–30 and 30–60 cm layers) were calculated. The result of the study showed a total of 38 woody plant species recorded from both HGAF and exclosures, but no report from cropland. The abundance, basal area, stem density, species richness, and Shannon and Simpson diversity indices were significantly higher in the HGAF than in exclosures. The mean SOC stock was the highest in HGs (122.13 ± 19.12 Mg ha-1). The estimated mean total ecosystem carbon stock of HGAF, cropland, and exclosure was 171.17 ± 37.25, 78.06 ± 11.97, and 92.5 ± 17.33 Mg ha-1, respectively, which was statistically significant among land use types. A positively significant correlation was observed between diversity, richness, and abundance of woody species and carbon stocks both in the HGAF and exclosure land use systems. The current study confirmed that increased woody species diversity in HGAF enhanced carbon sequestration. The HGAF land use in the northern parts of the country is scanty as compared to the southern part, where there is a rich woody species diversity. Therefore, it is recommendable to promote HGAF across agricultural landscapes of the study area, which enhances biodiversity conservation and mitigation of climate change impacts.

Woody species diversity and assemblage in different forest management stands of central Nepal

Various forest management strategies are in place for the conservation of forest ecosystems across the globe. Nepal is also implementing different forest management and restoration practices and has various impacts on vegetation characteristics. This study aims to compare the richness and diversity of woody plant species, and variability in abundance of woody species assemblages in different forest management stands, viz. restored stands inside Buffer Zone Community Forest (BZCF), natural stands of BZCF and core stands of Parsa National Park. Thirty sampling plots of 30 m × 30 m were laid on each stand, maintaining at least 50 m distance between the plots, where woody plant species having height 1.5 cm was identified and their DBH measured. Species composition was assessed comparing Importance Value Index (IVI) of woody plant species across the forests. Similarly, species diversity and structural diversity across stands were determined using Shannon Diversity index and basal areas of the plant species were calculated. The study showed Shorea robusta and Lagerstroemia parviflora with highest frequency (&gt;80%) in all the sites, and the species diversity was highest in the core stands inside the national park followed by the natural stands of BZCF, and the restored stands of BZCF. Basal area of overall species and density of S. robusta were, however, highest on the restored stands of BZCF, whereas overall density was highest in the natural stands of the BZCF. The study revealed that the forest management practices need improvement in enhancing the plant species diversity of the ecosystems. We recommend to assess the functional attributes of the different forest management stands to evaluate the effectiveness of forest management strategies.

Diversity, Distribution and Vegetation Assessment of Woody Plant Species in the Cold Desert Environment, North-Western Himalaya, India

The species richness, distribution and community structure in cold desert regions across the world are poorly understood because of their inaccessibility and remoteness. Similarly, the structure and composition of forest resources, including other management units (i.e., agroforestry and forestry systems), have hardly been studied in the cold desert of the Lahaul valley. However, such information is a prerequisite to understanding the trends and changes in the vegetation distribution under global climate change scenarios, especially considering the sensitivity of plant species in high-altitude areas of the Himalayan region. High anthropogenic activity has exerted tremendous pressure on available forest resources, including other management units in the cold desert of the Lahaul valley. Standard ecological methods were used to obtain an ecological (i.e., status, structure, composition and vegetation patterns) understanding of the region for biodiversity conservation and environmental sustainability. The present study was aimed at understanding the trend, structure and composition of plant species in the cold desert region of the western Himalaya. A total of 64 species (27 trees and 37 shrubs) of vascular plants were recorded in the present study. Tree diversity demonstrated greater variation along the gradients and slope aspects. Salix fragilis trees, with a 102 tree ha−1 density and a few trees of Populus nigra, were found to be sparsely distributed under the agroforestry system on the south-facing slopes in Khoksar. In Jahlma, Salix fragilis grew in an agroforestry system with a density of 365 tree ha−1. However, in Hinsa, Juniperus polycarpos was a dominant tree species in the agroforestry system, with a density of 378 tree ha−1. On the north-facing slopes in Kuthar, a higher number of trees and bushes were present due to natural regeneration maintained by farmers along the edges of terraced agricultural fields. The south-facing slopes showed a relatively lower species richness and diversity as compared to north-facing slopes at similar locations due to relatively less favourable growth conditions under sun-exposed, extremely xeric soil conditions. The highest level of species turnover was found between the altitudes of 2400 m and 3000 m. Betula utilis showed the highest adaptability at higher altitudes (&gt;3500 m). The vegetation analysis results and information generated in the present study are useful for gaining an ecological understanding of the cold desert ecosystem in the Lahaul valley. Sustainable forest resource management, including other management units (e.g., agroforestry and forestry systems), is crucial for improving the vegetation pattern, structure and function of the cold desert ecosystem, thereby contributing to climate change mitigation, adaptation, biodiversity and ecosystem service conservation.

Woody species diversity and regeneration status of Sub-Alpine forest of Mount Adama exclosure site, Northwestern highlands of Ethiopia

Forests provide a wide range of ecosystem services. Despite these facts, the expansion of agriculture and settlement at the expense of forest resources has threatened the forest resources and results in biodiversity loss. To halt this problem, various conservation practices that believed to restore the degraded lands and biodiversity of the country have been implemented. Area exclosure is among the conservation strategies that have been used to restore the degraded lands in Mount Adama forest. However, its role in woody species regeneration in Mount Adama was not investigated. Thus, the objective of the study was to evaluate the impact of area exclosure on woody plant species composition, regeneration status, structure and diversity in Mount Adama. A systematic transect sampling method was used to collect vegetation data. Hence, 53 plots with 400 m2 area were laid along 11 transects. Then, within the main plots, five subplots with 1 m2 were laid to determine the abundance and frequency of seedlings. The results showed that about 31 woody species that belong to 30 genera and 19 families including four endemic species were identified. The majority (67.74%) of the species were categorized under shrub habitat, while the remaining 19.35% and 12.90% were trees and lianas or climbers, respectively. Asteraceae family was dominant by contributing 4 species followed by Rosaceae and Solanaceae each contributed 3 species. Hypericum revolutum was the dominant species with 53.38 important value index followed by Erica arborea and Hagenia abyssinica with 49.12 and 40.05, respectively. The overall Shannon- Wiener diversity index and Shannon evenness in the exclosure site were 2.6 and 0.73, respectively. Furthermore, the number of seedlings and saplings were higher in the exclosure than the untreated site. The results of the study evidently showed that area exclosure that implemented in Mount Adam successfully contributed to the biodiversity restoration. Therefore, further conservation efforts targeting species with low IVI values are needed for sustainable management and ecological recovery of the area.

Net diversification rates of the woody plant genus Petalidium (Acanthaceae) are highest in the ancient and arid Namib Desert

At present, tropical arid biomes house less woody plant species diversity than tropical moist biomes, which could be due to lower rates of evolutionary diversification in the recent or distant past. Here, we study the evolutionary diversification of Petalidium (Acanthaceae), a genus of 36 species of woody shrubs found in the Namib Desert of southwest Africa, and surrounding areas. We generated a new, nearly fully sampled and temporally calibrated phylogeny for Petalidium using RADseq SNP data and secondary calibrations. We then investigated variation in net diversification rate across the phylogeny, the ancestral climatic niche of lineages and the link between the two. We find that arid climatic conditions are linked with increased rates of net species diversification in the genus. Despite its great age, the Namib Desert clearly hosts young plant radiations. This apparent contradiction can be explained by a scenario of high evolutionary turnover, in this case potentially caused by alternating hyper-arid and relatively mesic phases. Hyper-arid phases could result in high plant mortality and extinction of species, leading to ecological opportunity and diversification during mesic phases. Taken together, our results contribute to a growing body of literature that shows evidence for elevated rates of plant diversification in the Quaternary in arid biomes across the globe.

Species Diversity, Structure, and Regeneration Status of Woody Plants in Saleda Yohans Church Forest, South Wollo, Ethiopia.

The study was conducted to determine woody plant species composition, structure, and regeneration status in Saleda Yohans Church forest, South Wollo Zone, Ethiopia. Five transect lines oriented to north-south directions at a distance of about 500 m were laid down along transects across the forest. Fifty main plots of 20 m × 20 m were laid for tree/shrub data collection. Within each main plot, 5 small quadrats of 5 m × 5 m were laid in the corners and centre for the collection of seedling and sapling data of woody species. All vegetation data within the plots were counted and recorded. Tree height and diameters at the breast height of plants were also measured and estimated. Moreover, frequency, basal area, diversity, evenness, and other vegetation data were analyzed. The result showed that this Church forest is composed of 50 woody plant species distributed in 31 families. The Shannon-Wiener diversity index and evenness values of the forest were found to be 3.82 and 0.84, respectively. Lamiaceae was the dominant family followed by Fabaceae in their species composition. The density of trees/shrubs, saplings, and seedlings was 625, 650, and 935 ha-1, respectively. Based on the result, the entire vegetation of Saleda Yohans Church forest is in good regeneration status. In conclusion, although this Church forest appears to be in a good regeneration status, its species richness is low compared to a similar study of some other vegetation. Therefore, attention should be given to the rehabilitation of this forest.

Impact of Prosopis velutina Wooton on the Composition and Diversity of Native Woody Species in a Semi-Arid Zone along the Molopo River, South Africa

Invasive alien species represent one of the main threats to biodiversity and species extinction. This is the case for the genus Prosopis, among which Prosopis velutina is the most invasive and common tree species along the Molopo River in the North-West Province, impacting native plant communities. However, its impact on the composition and diversity of native woody species remains poorly investigated in the area. Thus, this study aimed to assess the impact of P. velutina on native woody plant composition and diversity across three sites along the Molopo River. At each site, five quadrats of 20 × 20 m2 were randomly established in invaded and adjacent uninvaded stands. A comparative methodological approach was adopted, and the woody plants in invaded and uninvaded stands with similar site conditions were sampled. The results showed that native woody species density differed significantly (p < 0.05) between invaded and uninvaded stands, except for Bray sites, where there was a marginal difference (p = 0.6). The overall native woody species density decreased by 79.7% in the invaded stand. However, non-metric multidimensional scaling (nMDS) and analysis of similarity (ANOSIM) indicated significant differences in native tree composition between invaded and uninvaded stands at all sites. In all three sites, all ecological indices had significantly lower values in invaded stands compared to uninvaded stands. The decrease in all ecological indices in invaded over uninvaded stands indicated that P. velutina invasion reduced the diversity of native woody plant species. Due to the incessant spread of P. velutina, it may become a long-term dominant species with an increasing impact on the native vegetation. Therefore, the findings of this study call for urgent management and appropriate control measures against the ongoing spread of this invader within the riparian zones of the Molopo River in North-West Province.

Does Ungulate Herbivory Translate into Diversity of Woody Plants? A Long-Term Study in a Montane Forest Ecosystem in Austria

Different species-specific traits of woody plant species, feeding preferences of herbivores together with resulting effects on plant competition are expected to translate into different plant community structures and expressions of biodiversity. We studied the diversity of woody plant species (trees and shrubs) and structural diversity of forest trees, using a 30-year and an 18-year dataset of ungulate exclosure-control plot pairs in a mixed alpine forest community in Austria. We surveyed the tallest individuals per tree species and plot and analyzed the collective of top-height individuals per plot pair. Incidence data for exclosure and control plots were aggregated. Comparing species diversity and diversity of height classes on the plots throughout time, we calculated diversity profiles based on Hill numbers. Diversity of top height individuals and structural diversity, expressed by height classes, were two diversity aspects that differed between exclosures and control plots. Other diversity estimates of woody plant species showed huge variation without significant differences between plots. Height growth was significantly suppressed by ungulate herbivory. Effects of ungulate herbivores in forest ecosystems are highly complex and context-dependent and thus not reducible to simple top-down forces. Long-term surveys provide data that reflect “ultimate” effects of herbivory interacting with other drivers of community dynamics.

Diversity, abundance, and conservation status of woody species in a West African dry forest

AbstractThis study presents data on woody plant species richness and diversity of an inaccessible dry forest of Tula Mountains Woodland (TMW) located in the northeast of Nigeria. TMW supports a minimally disturbed mosaic of dry forest‐woodland. We sampled woody species in 190 plots of size 0.01‐ha, spaced 50 m apart on series of line transects. We found a total of 133 woody species belonging to 88 genera and 39 families in 1.9 ha area sampled in total. Out of 133 species, 120 were identified to species level, and 113 were recorded as trees, shrubs and lianas with diameter at breast height (dbh) ≥ 5 cm. Species accumulation curve was non‐asymptotic. Fisher's logseries model suggests that the plots sampled in the dry forest communities of TMW are represented by a high number of rare species. Of 120 identified species, 46 (38%) lacked evaluation on conservation status by IUCN. Out of 74 (62%) evaluated species, 2 were listed as critically endangered, 3 were vulnerable, and 69 were of least concern. In the TMW, 27% of woody species were restricted to Sudanian savannah biome, 61% occurred in Sudanian and Zambezian savannah biome. TMW serves as refugia for native plant species and plant communities in northeastern Nigeria.

Effects of forest structure on woody plant diversity in an evergreen broadleaved forest in Cao Bang province

The present study was conducted in Phia Oac-Phia Den National Park in Cao Bang province to evaluate the interplay between forest structure and the diversity of woody plant species in an evergreen broadleaved forest. In six 1-ha permanent plots, all trees with a diameter at breast height (DBH) greater than 6 cm were identified, and their DBH, crown diameter, total tree height, and spatial coordinates were recorded. Spatial structure indices, non-spatial structure indices, and species diversity indices were utilized to construct a structural equation model (SEM). The results showed that the SEM model developed exhibited a good fit with CFI=0.98 and SRMR=0.02, signifying its accurate data modelling capabilities. The results emphasized the significant influence of both spatial and non-spatial structure on various woody plant diversity indices, including species richness, Shannon-Weiner diversity, Simpson diversity, and Pielou evenness. Notably, the horizontal spatial structure exerted a more pronounced effect on species diversity than the vertical structure. Furthermore, this study indicated a positive relationship between forest structure and diversity indices, highlighting their benefits. Conversely, interspecies competition negatively affected plant species diversity within the forest stands. This study provides a robust scientific foundation that supports effective strategies for the conservation and sustainable development of forest resources in the study area. It offers valuable insights for forest managers aiming to implement conservation and sustainability initiatives in the tropical evergreen broadleaved forest region.