The natural regeneration, demographic and spatial structure of Lophira lanceolata (Ochnaceae) populations in Côte d’Ivoire

Protected areas are the most commonly used tool for in situ conservation of biodiversity. Selective removal of species proposed by the local communities living surrounding the national park and grazing pressure negatively affect the composition, structure, and regeneration of woody species. Assessment of vegetation structure and regeneration status of woody species is essential for orienting management activities. The purpose of this study was to investigate the floristic composition, population structure, and regeneration status of woody species in the Loka Abaya National Park, to design conservation strategies. A total of 99, 20 m × 20 m quadrats were systematically laid along an established line transect to collect a list of woody species, abundance, height, and diameter at breast height (DBH), while five 3 m × 3 m subquadrats within the main quadrats were established to assess the regeneration status of woody species. In each quadrat, all woody species were identified, counted, and recorded. In each quadrat, all tree and shrub species higher than ≥2 m in height and ≥2 cm in diameter at breast height were measured by a calibrated wooden stick and by a caliper, respectively. Density, frequency, basal area, importance value index (IVI), height, and diameter at breast height (DBH) were used for description of vegetation structure, while the density of mature trees, saplings, and seedlings was used for assessment of regeneration status of woody species. A total of 101 woody plant species representing 40 families in 69 genera were collected, identified, and documented. Fabaceae was the most diverse family representing 16 (15.84%) species, followed by Euphorbiaceae 9 species (8.91%) and Anacardiaceae with 6 species (5.94%). Four families including Combretaceae, Moraceae, Olacaceae, and Tiliaceae were represented by 4 species each. 4 families were also represented by 3 species each, 12 families were represented by two species each, and 18 families were represented by one species. The density of trees was 831.31 individuals ha−1, while the total basal area was 73.18 m2·ha−1. D. angustifolia, C. molle, E. schimperi, R. natalensis, O. europaea L. subsp. cuspidataD. cinerea, A. brevispica, I. mitis, and E. tirucalli were ecologically important woody species. The majority (75%) of woody plant species had a less than 5% importance value index (IVI). The diameter class distribution of selected tree species demonstrated various patterns of population structure, implying the existence of different population dynamics among ecologically important tree species. The regeneration assessment results demonstrate that 32.35% had poor regeneration, 19.12% had good regeneration, 16.17% had fair regeneration, 8.82% lacked regeneration, and 14.08% appeared as newly regenerated species in the national park. The majority of woody species had a small population size, and some of them were found in specific habitats which need attention for conservation, and those woody species lack regeneration study soil seed bank and propagation methods for sustainable conservation.

The study was conducted in Kafta Sheraro National Park (KSNP) dry woodland natural forest located in Kafta Humera and Tahitay Adiyabo weredas (districts), Western and Northwestern Zones of Tigray regional governmental state, North Ethiopia. The objective of the study was to explore the floristic composition, structure, and regeneration of woody species in the home ofLoxodonta africanaL.,Hippotragus equinus,Anthropoides virgo,Ourebia ourebi,Crocuta crocuta,Tragelaphus strepsiceros,Phacochoerus africanus, and unidentified crocodile and fish species. In the park, the vegetation ecology has not been studied up to date which is necessary for conservation. The systematic sampling technique was used to collect vegetation and human disturbance (presence and absence) data from August to December 2018. The vegetation data were collected from 161 plots each with a size of 400 m2(20 m × 20 m) for tree/shrub while subplots of size 100 m2(10 m × 10 m) and 25 m2(5 m × 5 m) for sapling and seedling, respectively, were established in the main plots. Individual tree and shrub diameter at breast height (DBH) ≥2.5 cm and height ≥ 2 m were measured using tape meter and clinometer, respectively. Diameter at breast height (DBH), frequency, density, basal area, and importance value index (IVI) were used for vegetation structure description while the density of mature trees, sapling, and seedling was used for regeneration. A total of 70 woody species (46 (65.7%) trees, 18 (25.7%) shrubs, and 6 (8.6%) tree/shrub) were identified. The total basal area and density of 79.3 ± 4.6 m2·ha−1and 466 ± 12.8 stems·ha−1, respectively, were calculated for 64 woody species. Fabaceae was the most dominant family with 16 species (22.9%) followed by Combretaceae with 8 species (11.4%). The most dominant and frequent species throughout the park wereAcacia mellifera,Combretum hartmannianum,Terminalia brownii,Balanites aegyptiaca,Dichrostachys cinerea,Acacia senegal,Acacia oerfota,Boswellia papyrifera, Ziziphus spina-christi, andAnogeissus leiocarpus. Abnormal patterns of selected woody species were dominantly identified. The regenerating status of all the woody plant species was categorized as “fair” (18.75%), “poor” (7.81%), and “none” (73.44%). There was a significant correlation between altitude, anthropogenic disturbance (grazing and fire frequency), and density of seedling, sapling, and mature trees. But there was no correlation between gold mining and regeneration population. However, there is a good initiation for the conservation of the park; still, the vegetation of the park was threatened by human-induced fire following intensive farming, gold mining, and overgrazing. Therefore, the study area was the habitat for the population of the African elephant; species with low importance value indices and lack or having few seedling and sapling stage should be prioritized for conservation, and their soil seed banks should be studied further.

When compared to planted reforestation, natural unassisted regeneration is often reported to result in slow recovery of biomass and biodiversity, especially early in succession. In some cases, naturally regenerating forests are not comparable to the community structure of primary forests after many decades. However, direct comparison of the outcomes of tropical forest restoration and natural regeneration is hindered by differences in metrics of forest recovery, inconsistency in land use histories, and dissimilarities in experimental design. We present the results of a replicated reforestation experiment comparing natural regeneration and polyculture tree planting at multiple diversity levels (3, 6, 9, or 12 native tree species), with uniform land use history and initial edaphic conditions. We compare the recovery of basal area and floristic diversity in these treatments after 5 yr of succession. Total basal area was higher in planted plots than in naturally regenerating plots, but it but did not vary among the different planted diversity levels. The basal area of woody recruits did not differ among treatments. The diversity of woody recruits increased substantially over time but did not vary among planting treatments. Species composition trajectories showed directional turnover over time, with no consistent differences among treatments. The convergence of restoration trajectories and similarity of floristic community diversity and composition across all treatments, after only 5 yr, provides evidence of the viability of natural regeneration for rapid restoration of forest biodiversity.

Natural regeneration is an indicator of a healthy forest, hence, understanding the influence of site factors on natural regeneration is a significant concern for ecologists. This work aimed to assess the impact of site factors on natural tree regeneration at Khadimnagar National Park (KNP). Biotic factors (tree density, tree species richness, and basal area), physical factors (elevation, canopy openness), and soil properties (bulk density, moisture content, soil pH, organic matter, sand, silt, and clay) data were investigated from 71 sample plots to examine their effects on natural regeneration density and richness in KNP. Stepwise multiple linear regression analysis was done to predict both regeneration density and regeneration richness. The results showed that soil pH (p<0.001), canopy openness (p<0.001), tree species richness (p<0.01), and bulk density (p<0.01) had a significant effect on regeneration density, explaining 42% of the total variation. Regeneration richness was driven by four factors: tree species richness (p<0.01), soil pH (p<0.001), elevation (p<0.01), and canopy openness (p<0.01) with a model that explained 60% of the total variation. This study observed that soil pH, tree species richness, and canopy openness are the main controlling factors that influenced both the density and richness of regenerating species in KNP. Therefore, these findings have implications for natural resource management, especially in selecting suitable silvicultural systems in a tropical forest under protected area management where enhanced tree cover and conservation of biodiversity are needed.

QuestionIncreases in the cover of woody plants have been documented in woodland, savanna and grassland ecosystems across the globe, commonly attributed to changes in land use or disturbance regimes. This is often thought to result in alternative stable states resistant to reversal. However, some multi‐decadal‐scale studies have found woody plant cover fluctuates according to variations in rainfall. After a decade‐long El Nino event, we ask: can severe drought reverse woody plant encroachment in a temperate Australian woodland?LocationTemperate coastal woodland in Victoria, SE Australia that has remained unburned for over a century.MethodsUsing data spanning 41 yr, changes in basal area and tree density were assessed for the major woody species in a eucalypt woodland. Data were used to determine whether a decade of severe drought (1997–2009) had reversed a previously identified phase of woody plant encroachment (1971–1996).ResultsAfter an increase in stand density between 1971 and 1996, attributed to an increase in the fire‐sensitive species Allocasuarina littoralis, total tree density then declined by 42% between 1996 and 2012. Changes in tree density differed across dominant woody species (A. littoralis −34%, Allocasuarina verticillata +26%, Acacia pycnantha −78%, Banksia marginata −73%, Eucalyptus spp. −97%), and seedling recruitment almost completely ceased for all species. However, the basal area of A. littoralis (having almost doubled between 1971 and 1996) had continued to increase by 75%, with increases highest in areas where initial basal area was lowest. Despite this increase, total stand basal area remained relatively stable, with an increase of 5%, because of a combined decline in basal area for all other species of 62%.ConclusionDespite the most severe drought on record, site occupancy – as measured by basal area – did not decline between 1996 and 2012. Thus, severe drought did not reverse woody plant encroachment. Rather, findings were consistent with the previous trend of increasing A. littoralis dominance at the expense of other tree species in the long‐term absence of fire.

The aim of this study was to analyse the species composition, structures, and regeneration of woody plant species and the impacts of site factors on the natural regeneration of tree species in four study sites of MFBR. The vegetation data were collected systematically in 140 plots with the size of 400 m2 for trees; 25 m2 for seedlings, saplings, shrubs, and lianas; and 1 m2 for herbs. Individual tree and shrub DBH ≥ 5 cm were measured and counted. The diameter at breast height (DBH), frequency, basal area, importance value index (IVI), and density were used for vegetation structure description and regeneration. A total of 158 plant species belonging to 115 genera, 56 families, and 80 species (51%) trees, 26 (16%) shrubs, 19 (12%) herbs, and 33 (21%) lianas were identified and recorded. The most dominant families were Euphorbiaceae, Rubiaceae, and Moraceae, each represented by 13 species (7.4%), 12 species (6.8%), and 10 species (5.7%), respectively. The tree densities varied from 1232 to 1478 stem ha−1, sapling density 176.8 to 708.7 stem ha−1, and seedling density 534.7 to 1657.5 stem ha−1, with an average basal area of 63.6 m2 in the study sites. Dracaena afromontana was the most frequent woody species in the MFBR occurring in 90% followed by Celtis zenkeri (65%) and Pouteria altissima (62.5%). The regeneration status of all the woody plant species was categorised as “not regenerate” (9.6%), “poor” (30.7%), “fair” (59.5%), and “good” (10.8%) in all sites. The correlation result between natural regeneration and site factors revealed both positive and negative relationships. However, the main threat to the biosphere reserve is illegal logging for different purposes. Therefore, awareness creation on sustainable forest management, utilisation, conservation of priority species, and livelihood diversification to the local community and encouraging community and private woodlot plantation in the transitional zone of biosphere reserves are recommended.

The study was conducted in protected woodland and free graze woodland located in Dugda Woreda, Oromia state, Ethiopia. The objective of the study was to explore the floristic composition, structure, and regeneration of woody species. In the park, the vegetation ecology has not been studied up to date, which is necessary for conservation. The systematic sampling technique was used to collect vegetation and human disturbance (presence and absence) data from August to December 2017. The vegetation data were collected from 30 plots from each woodland with a size of 900 m2 (30 m × 300 m) for tree/shrub, while subplots of size 400 m2 (20 m × 20 m) for sapling, respectively, were established in the main plots. Individual tree and shrub diameters at breast height (DBH) ≥2.5 cm and height ≥ 2 m were measured using a tape meter and clinometer, respectively. Diameter at breast height (DBH), frequency, density, basal area, and importance value index (IVI) were used for vegetation structure description, while the densities of mature trees, sapling, and seedling were used for regeneration. A total of 446 individual stems from free grazed woodland and 641 individual stems from protected woodland with a DBH of ≥2.5 cm were encountered from 30 studied sample plots that are protected and free grazed woodlands. Of these, from the total woody species, 68.42% were trees and 31.57% shrubs found in protected woodland; 76.92% were trees and 23.07% shrubs found in free grazed woodland. The total basal area of the woody plant was 3.1 ± 1 m2/ha in free grazed woodland and 4.2 ± 2 m2/ha in protected woodland, calculated for 19 woody species. Fabaceae, Balanitaceae, Capparidaceae, Verbenaceae, and Boraginaceae families were the most abundant families in both woodlands. However, there is a good initiation for the conservation of the park; still, the vegetation of the park was threatened by human-induced fire following intensive farming, gold mining, and overgrazing.

Ecology and management history drive spatial genetic structure in Scots pine

Natural forest regeneration, i.e. self-renewal of forest stands, involves the replacement of old trees by the next generation and is influenced by environmental factors. The spatial structure of tree regeneration depends on and also influences the properties of the stands themselves. Few studies have investigated spatial patterns of naturally regenerated areas in Mexican pine–oak forests, which are considered one of the world’s top 34 biodiversity hotspots. In this study, we analyzed the spatial patterns, particularly the spatial structure, in clusters of naturally regenerated trees in seven 100 × 100 m plots in the Sierra Madre Occidental (northern Mexico), in relation to three factors: slope, geographical aspect and distance between each sapling to the edge of the nearest gap in the canopy. Three indices were used to describe spatial structure and the data were analyzed by bivariate Ripley’s K(t)-functions and three-parameter and six-parameter Weibull models. The results indicate that sapling regeneration was marginal in canopy gaps. Sapling density was ten times higher under the canopy cover, close to the edge than in the gaps. On average, the first maximum number of saplings was detected inside the canopy at about 81 cm from the gap edge, forming ring-type spatial patterns around the canopy gaps. These results contrast with the gap dynamics described in many other studies. We attribute these findings to the nurse effect of trees, which ameliorate abiotic effects, such as the extreme drought that occurred in 2011 and 2012 in the study region. In covered zones close to canopy edges, thece orientation. We recommend adapting or changing the current forest management system to improve continuous forest regeneration (including adaptive silviculture). We also strongly support i) research on the effects of cattle grazing on natural regeneration in the region and ii) reduction of livestock pressure, which is essential to support forest renewal. Complementary reforestation, in addition to maintenance of the few saplings growing within the gaps, may help enhance forest regeneration. Finally, the use of alternative regeneration methods, such as an irregular group shelterwood method (Expanding Gap Silviculture “Femelschlag”), should also be considered, in order to promote natural regeneration more purposefully.

West African Guinean forests are among the most diverse and threatened ecosystems in the world. The study aims to provide new insights about tree species patterns, abundance, and diversity for better management in Togo. Species diversity and density of trees were assessed in 170 plots randomly selected in the study area. Each tree with DBH >10 cm was identified and measured. Stem density, basal area, and diversity indices were calculated. In total, 243 species belonging to 170 genera and 44 families were identified in the study area. Five floristic groups were recognized. They are characterized respectively by Lophira lanceolata, Pterocarpus erinaceus and Daniellia oliveri association in Group 1; Theobroma cacao, Elaeis guineensis and Morinda lucida association in Group 2; Elaeis guineensis, Persea Americana and Albizia zygia association in Group 3; Cola gigantea, Senna siamea and Erythrophleum suaveolens association in Group 4 and Pycnanthus angolensis, Ceiba pentandra and Pseudospondias microcarpa association in Group 5. The Fabaceae, Moraceae and Malvaceae are the most represented families in the study area. The highest tree species diversity was observed in Group 4 (2.05 ± 0.61) and the lowest diversity in Group 2 (1.19 ± 0.64). Mean tree density ranges from 408.96± 202.17 (Group 1) to 273.90 ± 193.19 (Group 4). The highest tree basal area (27.99 ± 25.58 m2/ha) is obtained in Group 3 and the lowest (15.84 ± 13.44 m2/ha) is in Group 4. The presence of pioneer species in the study areas proves that the habitat has undergone serious anthropogenic disturbance events, which contribute to species loss.   Key words: Diversity, sub humid mountains ecosystems, Togo, richness, tree species, disturbance factors.

Post-fire ponderosa pine regeneration with and without planting in Arizona and New Mexico

Studying of the demographic characteristics of populations of alien species at the stage of expansion makes it possible to assess their invasive potential. Field studies of alien terrestrial gastropods Xeropicta derbentina (Gastropoda,Stylommatophora, Hygromiidae), Brephulopsis cylindrica (Gastropoda, Stylommatophora, Enidae) and Harmozica ravergiensis (Gastropoda, Stylommatophora, Hygromiidae) have been carried out in Belgorod city, the southern part of the Central Russian Upland (Russia). All studied species are native to the Black Sea region and the Caucasus; in the southern part of the Central Russian Upland, they have been registered over the past ten years. The population density, demographic structure, and spatial structure have been analyzed for three years of observations (2017, 2019, 2020). During this period, the changes in the population density have been noted for all studied species. The most pronounced changes have been observed in X. derbentina, whose population density has significantly decreased, and the spatial structure has changed from clustered type to random distribution. In addition, the age structure of X. derbentina population had a pronounced change at the beginning of the snail activity season of 2020. The expansion of the other two invaders, B. cylindrica and H. ravergiensis, is proved as more successful. At the same time, H. ravergiensis is distributed throughout the city. This species has stable population density and random type of spatial population structure on most sites. B. cylindrica has the highest population density: in 2020, it has reached 406 ind./m2 on average, with the maximum of 1215 ind./m2.Meantime, the species keeps the clustered spatial structure, which is explained by both high population density and adaptation to the arid conditions of its natural range.

Summary 1. Birds inhabiting farmland are of conservation concern around the world. In Australia, conservation management has focused primarily on woodland environments. By contrast, semi-natural open areas have received less attention. We argue that long-term conservation strategies should consider broad gradients of environmental conditions. Otherwise, there is a risk that semi-natural open areas will degrade through ‘benign neglect’, and currently common species using these areas will become uncommon. 2. We examined how birds responded to three environmental gradients in an Australian livestock grazing landscape: tree density, grazing intensity and nutrient enrichment. First, we investigated changes in species composition across the environmental gradients in multivariate space. Secondly, we modelled species richness and the response of selected individual species in relation to the gradients. Thirdly, we examined if there were patterns in guild composition and body mass distribution. 3. Tree density was the primary driver of virtually all patterns observed. Species richness peaked at moderately high tree densities. With increasing tree density, species composition changed, foraging guild composition changed and the median body mass of bird species decreased. Small insectivores were more likely to occur in areas with high tree densities, whereas large granivores were more likely to occur in areas with relatively low tree densities. Grazing intensity and nutrient enrichment were less strongly related to bird distribution patterns, although the indirect effects of these gradients may be substantial because they affect tree regeneration. 4. sSynthesis and applications. Relatively dense woodland patches were important for species already of conservation concern, lending support to their active conservation management, for example through livestock exclusion. However, semi-natural open areas also were used by many birds, which represented a different mix of body sizes and foraging guilds. Scattered trees occurring at a range of densities are key habitat elements in semi-natural open areas. However, many scattered trees are dying and are not being replaced by natural regeneration or tree planting. If areas with scattered trees continue to degrade, there is a risk that currently common farmland birds will decline. Management strategies aiming to maintain scattered trees therefore are important, including the planting of individual trees and the adoption of grazing practices that allow for natural tree regeneration.

Forest edges in managed riparian forests in the eastern part of the Czech Republic

Evaluating the success of direct seeding for tropical forest restoration over ten years