Regeneration Of Native Species Research Articles

Loquat (Eriobotrya japonica) fruit consumption and preference by cloud forest birds: Implications for woody native species regeneration

Secondary forests from abandoned shade coffee plantations are commonly found close to Neotropical cities. These peri-urban forests provide important environmental services; however, their abandonment and proximity to the city can promote an increase of exotic species that could potentially change the structure and function of the system by creating novel ecosystems. The loquat (Eriobotrya japonica) is a tree native to Asia and is recognized as a potentially invasive species in the tropical montane cloud forest region of Central Veracruz, Mexico. We analyzed the consumption of and preference for loquat fruits in cloud forest frugivorous birds. In November 2020, we established six feeding stations with camera traps in a peri-urban cloud forest fragment in Xalapa, Mexico. To determine which bird species could consume and disperse E. japonica, fruits of this and another four native species (Psychotria nervosa, Hoffmannia excelsa, Picramnia antidesma, and Xylosma flexuosa) were exposed separately. After 444 camera-days, we recorded eight frugivorous bird species, seven of which consumed E. japonica fruits. Chlorospingus flavopectus was the only species to present a level of loquat fruit consumption greater than that expected by chance. We conducted experiments to assess whether the birds preferred to consume E. japonica fruits compared to those from three native species (Cestrum miradorense, P. nervosa, and X. flexuosa) that were offered simultaneously. All bird species exclusively consumed E. japonica fruits when contrasted against P. nervosa or X. flexuosa. The only native species fruits that were consumed were those of C. miradorense, although the birds also preferred to consume loquat fruits rather than this native species. The loquat therefore represents an important food resource and could act to influence the consumption and dispersal of native cloud forest plant species. The implications for cloud forest management are discussed.

EFFECT OF FUNCTIONAL STRATEGIES AND ABUNDANCE OF Acacia mangium Willd ON THE NUMBER OF NATIVE SPECIES IN A SECONDARY FOREST FRAGMENT IN SOUTHERN AMAPA, BRAZIL

Acacia mangium Willd is a fast-growing exotic tree that, when inserted in a different environment, can present an invasive potential in secondary forests. This study aimed to analyze the effect of abundance and functional strategies of A. mangium Willd and edaphic factors on native species richness in a secondary forest fragment located behind the Instituto Federal do Amapá campus Laranjal do Jari, Amapá. For this, all tree individuals with diameter at breast height (DBH) ≥ 10 cm occurring in 10
 plots of 200 m2 distributed in the fragment were identified. Soil samples were collected in the plots and sent for fertility and granulometry analysis. Three leaf functional attributes of individuals of A. mangium Willd occurring in the plots were measured: leaf area (LA), leaf thickness (LT) and specific leaf area (SLA). A total of 145 tree individuals and 14 species were sampled, with A. mangium Willd being the most abundant with 95 individuals. The relative abundance of A. mangium Willd was negatively related to native species richness in the fragment. The species also exhibited distinct leaf attributes and abundances according to the variation in soil acidity and fertility in the fragment, which influenced the number of native species. There is a need to develop monitoring and management of invasive exotic species such as A. mangium Willd in fragments of secondary forests, since the species is invasive and opportunistic, and can inhibit the regeneration of native species after local disturbances.

Green deserts, but not always: A global synthesis of native woody species regeneration under tropical tree monocultures.

Tree monocultures constitute an increasing fraction of the global tree cover and are the dominant tree-growing strategy of forest landscape restoration commitments. Their advantages to produce timber are well known, but their value for biodiversity is highly controversial and context dependent. Therefore, understanding whether, and in which conditions, they can harbor native species regeneration is crucial. Here, we conducted meta-analyses based on a global survey of the literature and on a database created with local, unpublished studies throughout Brazil to evaluate the regeneration potential of native species under tree monocultures and the way management influences this regeneration. Native woody species regeneration under tree monocultures harbors a substantial fraction of the diversity (on average 40% and 68% in the global and Brazilian surveys, respectively) and abundance (on average 25% and 60% in the global and Brazilian surveys, respectively) of regeneration observed in natural forests. Plantations with longer rotation lengths, composed of native tree species, and located adjacent to forest remnants harbor more species. Pine plantations harbor more native individuals than eucalypt plantations, and the abundance of regenerating trees is higher in sites with higher mean temperatures. Species-area curves revealed that the number of woody species under pine and eucalypt plantations in Brazil is 606 and 598 species, respectively, over an aggregated sampled area of ca. 12 ha. We highlight that the understory of tree monocultures can harbor a considerable diversity of regenerating native species at the landscape and regional scales, but this diversity strongly depends on management. Long-rotation length and favorable location are key factors for woody regeneration success under tropical tree monocultures. Therefore, tree monocultures can play a role in forest landscape restoration and conservation, but only if they are planned and managed for achieving this purpose.

Forest land management and the role of ecological silviculture on the sustainability of Greek forests

One of the challenges faced by current forestry practice is how to effectively respond to the great environmental and global changes to achieve biodiversity conservation and the demands for timber and other non-wood forest products. Worldwide forestry suggests that the approach of ecological silviculture can provide efficient tools for facing these challenges. The applied forest land management during the last seven decades in Greece relies on the principles of sustainability set by ecological silviculture through time. Greek silviculturists adopted these principles many years ago by setting the following priorities and perspectives for applied Greek forestry: the protection of all Greek forests, the systematic rehabilitation of degraded forests (e.g., conversion of coppices to high forest), the promotion of tree species mixture, the improvement of the horizontal and vertical structure of all forest ecosystems, the exclusive use of species natural regeneration, the application of selective felling prohibiting any of clear-cutting, the extensive use of low impact harvesting practices, the retention of a small number of old trees for promoting biodiversity, the protection of all rare and endangered flora and fauna species, and establishment forest protected areas. In this study, three modern indicators were used to evaluate the results of the above silvicultural ecological approach to Greek forests after a period of seven years of forestry practice based on these principles.

Silvicultural Practices for Diversity Conservation and Invasive Species Suppression in Forest Ecosystems of the Bundala National Park, Sri Lanka.

Forest ecosystems in Sri Lanka are under pressure from intensive human activity and climate change. Invasive species are one of the greatest threats to autochthonous species and ecosystems. In Bundala National Park of Sri Lanka, there are efforts to control and limit the spreading of unwanted invasive Prosopis juliflora (Sw.) DC. and Opuntia dillenii (Ker-Gawl.) Haw., which poses a significant risk to natural ecosystem conservation. Nine different treatment variants (four replications) were used to test which management approach provides the control of Prosopis juliflora. This research is based on nine repeated measurements from 2017 to 2021 on 36 permanent research plots (each 625 m2) with 27 observed plant species and a total of 90,651 recorded plant individuals. The results confirmed that the dynamics of species richness, heterogeneity, and evenness showed significant differences between treatments during the five years of dynamics. The lowest species diversity was found in the control variant, followed by treatments based on the hard pruning and thinning of Prosopis juliflora trees. In contrast, strategies emphasizing the complete uprooting of Prosopis juliflora trees, replanting, and support of the natural regeneration of native species showed high species diversity and a high overall number of plant species. Generally, treatments had a significant effect on species diversity and the number of individuals of Prosopis juliflora, while changes in the overall number of plant species were more affected by time and succession. Silvicultural treatments including pruning, uprooting, and thinning have proven to be essential tools for nature conservation across various sites, aimed at enhancing habitat diversity in the face of ongoing climate change.

Delaying a prescribed burn to scale up the restoration of alien‐invaded Lowland Sand Fynbos in South Africa

AbstractFire‐adapted species invading fire‐prone ecosystems in Mediterranean climate regions are difficult to control because they are equally responsive to restoration treatments. We assessed the efficacy of delaying a prescribed burn to promote the recruitment of native species in a Lowland Sand Fynbos ecosystem invaded by alien Acacia saligna. Acacia stands were felled and fallowed for 2 years before burning the slash and sowing pre‐treated fynbos seeds. We hypothesized that sowing pre‐treated fynbos seeds after fallowing cleared areas before burning would improve the regeneration of native species. Fallowing cleared areas would reduce the density of acacia seeds and post‐fire acacia recruitment while allowing felled acacia biomass to dry and decay over time leading to improved prescribed burn properties. Sowing pre‐treated fynbos seeds improved the recovery of native cover but had little effect on the recovery of native species diversity after 2 years. Although the rapid recruitment of annual native species did not affect acacia density, it might have contributed to reduced post‐fire acacia cover and allowed the native perennial species to establish. After 2 years of fallowing cleared areas, the density of acacia seeds and post‐fire acacia recruitment was reduced by ≈50% and 80% respectively. Although too dense to be outcompeted by recruited native species alone, this reduced acacia recruitment helped to decrease and delay the need for follow‐up acacia clearing as it was where burning occurred soon after felling acacia stands. The recruited native species managed to establish before the acacia emergents were removed unlike where burning occurs soon after felling and where native species were outcompeted resulting in the need for follow‐up sowing. In conclusion, building resilience against acacia resurgence by increasing the pool of sown species to recover a good cover of native species in combination with the timely removal of acacia recruits can help to scale up restoration.

Considering both sexual and clonal reproduction could help loosen the conflict of use over Robinia pseudoacacia

Black locust (Robinia pseudocacacia) is a widely planted tree for wood production; however, it is a very problematic invasive species through Europe. At local scale, this tree is able to invades adjacent ecosystems owing to its strong ability of asexual reproduction through root suckers. Due to this phenomenon, the role of sexual reproduction has been quite neglected at local scale. Here, we propose a double approach (i) to evaluate the ability of the species to develop under forest cover using French national forest inventory data (ii) to quantify the role of sexual and asexual reproduction at local scale using a simple visual assessment method. We evidenced that juvenile black locust regenerates in broadleaved forests where R. pseudoacacia did not contribute to the adult canopy; moreover, a significant higher presence in riparian forests relatively to non-riparian ones was demonstrated using national forest inventory data. Regeneration from sexual reproduction mode significantly contributes to local scale invasion (38% of the up-rooted juvenile plants) with a significantly higher ratio of sexual reproduction within oak dominated forests compared to pine dominated ones. We conclude that black locust forestry should consider that both reproduction modes contribute to the species natural regeneration and that both modes can occur under both coniferous and broadleaved forest cover. Thus, we propose to set up safety buffers around sensitive ecosystems such as natural reserves or riparian areas, to maintain black locust cultivation while minimising undesired invasions in natural areas.

Drivers of Native Species Regeneration in the Process of Restoring a Dry Evergreen Forest from Exotic Tree Plantations in Northeastern Thailand

Establishment of exotic plantations is one of the most effective ways to induce natural regeneration for the restoration of degraded lands, as it has the potential to improve soil properties and creates favorable microclimates. This study aims to determine the effects of stand structure and composition as well as environmental factors under the canopies of three exotic plantations in northeastern Thailand on the regeneration of native species. For each plantation, we conducted three 10 m × 150 m transect lines with fifteen 10 m × 10 m subplots along a forest remnant gradient. The canonical correspondence analysis (CCA) was used to identify the environmental factors responsible for the differences in natural regeneration among these stands. Three exotic plantations had different stand structure in terms of number of tree species, basal area, and tree density but similar dominant native tree species. Across all stands, 74 native tree species, 60 genera, and 30 families were observed. Some physical and chemical properties in the topsoil were significantly different between species but similar among stands within a species. On the other hand, differences in environmental factors such as RLI were significant among species and stands within a species. The CCA ordination identified that the soil particles, soil pH, and light intensity were key factors influencing the native species composition, which could be categorized into three groups: drought-tolerant pioneer species; light-demanding pioneer species; and shade-tolerant climax species. However, most of the climax species were incapable of regenerating and maturing along the forest edge gradient to plantation stands. To accelerate the restoration process by converting these old exotic plantations to a dry evergreen forest, further research is required to determine the appropriate canopy management and/or dominant climax species for planting beneath their canopies.

Identifying long-term stable refugia for dominant Castanopsis species of evergreen broad-leaved forests in East Asia: A tool for ensuring their conservation

Identifying and protecting refugia is a priority for conservation management under projected anthropogenic climate change. We have two main objectives: the first is to explore the spatial (East Asia) and temporal (Last Glacial Maximum to year 2070) distribution patterns of dominant Castanopsis species of evergreen broad-leaved forests, also the relation with their niche breadths; the second is to identify long-term stable refugia for preserving these species and provide a framework of conservation strategies. We find that there is an extraordinary richness with 32 dominant Castanopsis species, and they form both a geographically and climatically almost unbroken connection from ca. 5°N to 38°N, having thus ecological significance. During the Mid-Holocene and, particularly, the Last Glacial Maximum, the predicted suitable areas of the species as a whole were larger than those in the present. By 2070, potentially suitable areas with high richness of dominant Castanopsis species will be reduced by 94.5 % on average. No correlation between species niche breadths and distribution ranges is found, which could be due to regional climate stability. Mountains of southwestern and southern Yunnan in China are identified as climatically long-term stable refugia for 7–9 Castanopsis species. We recommend that these refugia have the highest priority of conservation to prevent their extinction. Our suggested urgent measures include improving the effectiveness of currently protected Castanopsis species and expanding the network of protected areas to cover a larger fraction of the refugia, as well as ensuring Castanopsis species natural regeneration potential in fragmented and natural secondary forest areas.

Removal of non-native trees fosters but alone is insufficient for forest regeneration in Hawaiʻi

Across the globe, non-native plant species have become abundant in many tropical forests, resulting in altered patterns of biological diversity and species composition, and impacting important ecosystem functions. However, long-term experimental research on the efficacy of non-native tree removal for tropical forest restoration remains limited. We investigated the removal of non-native tree species in a mesic tropical forest in Hawaiʻi, where rates of endemism and endangerment of plant species is high and multiple non-native tree species are abundant. As a collaboration between resource managers and researchers, we tested the effects of non-native tree removal on overstory and understory metrics of restoration using three restoration approaches: “total cut” (cutting all non-native trees); “girdle” (girdle of all non-native trees); and “selective cut” (cutting approximately 50% of non-native trees). Prior to removal, we established permanent plots (four 10 × 10 m plots per restoration treatment, with 10 1 × 1 m subplots in each), then monitored them over 10 years. Across all treatments, canopy openness increased significantly post restoration, peaked after three years, then decreased to pre-treatment levels or lower. The increase was largest for the total cut treatment, but there was large variation within treatments. By the end of the experiment, the total cut and girdle treatments performed similarly for all our metrics of restoration, including survival, growth, density, and basal area of native trees; density and richness of native species in the understory; and total weed biomass. The selective treatment performed worse, showing lower relative gains in basal area of native trees and density of native understory individuals. Overall, tree removal was effective in restoring a native canopy. However, understory native species richness and density remained at pre-treatment levels, likely due to limited seed dispersal, seed predation by non-native rodents, and continued competition from non-native herbaceous species. Nonetheless, subplots with the best starting conditions performed the best. More intensive and longer-term weeding of non-native species in the understory, focused on areas with the best starting conditions and combined with out-planting of native seeds, seedlings and/or saplings, is likely necessary to foster effective native species regeneration. Overall, our research shows that removal of non-native trees using the total cut and girdle techniques can foster native forest restoration in the mesic forests of Hawaiʻi, but that on-going long-term management in the understory is critical.

Biochar Rescues Native Trees in the Biodiversity Hotspot of Mauritius

Many tropical invasive species have allelopathic effects that contribute to their success in native plant communities. Pyrolyzed biomass (“biochar”) can sorb toxic compounds, including allelochemicals produced by invasive plants, potentially reducing their inhibitory effects on native species. Strawberry guava (Psidium cattleianum) is among the most important allelopathic invasive species on tropical islands and recognized as the most serious threat among invasive species in the global biodiversity hotspot of Mauritius. We investigated the effects of additions of locally produced biochar on native tree species in a field experiment conducted in areas invaded by strawberry guava within Mauritius’ largest national park. Growth and survivorship of native tree species were monitored over 2.5 years in plots subjected to four treatments: non-weeded, weeded, weeded + 25 t/ha biochar, and weeded + 50 t/ha biochar. Native tree growth and survivorship were strongly suppressed by strawberry guava. Biochar treatments dramatically increased native tree performance, with more than a doubling in growth, and substantially increased native tree survivorship and species diversity, while suppressing strawberry guava regeneration, consistent with growth-promoting properties and sorption of allelochemicals. We conclude that biochars, including “sustainable biochars” produced from locally accessible biomass using low-tech pyrolysis systems, have considerable potential to counteract effects of allelopathic invaders and increase the capacity for native species regeneration in tropical island ecosystems.

Seed rain and soil seed bank in Chinese fir plantations and an adjacent natural forest in southern China: Implications for the regeneration of native species.

The natural regeneration of native broadleaved species underneath forest monoculture plantations is important to recover ecosystem functions and to mitigate adverse environmental effects. To understand how seed rain and soil seed bank facilitate natural regeneration, we surveyed their density and composition in a monoculture Chinese fir plantation, a mixed Chinese fir–broadleaf plantation, and an adjacent natural broadleaved forest for two years in southern China. Twenty‐eight species (16 families) were in seed rain, and 45 species (27 families) were in soil seed bank. Seed rain density did not differ significantly across stands; however, the number of taxa in seed rain was highest in the mixed plantation and lowest in the natural forest. Seed bank density was significantly higher in the mixed plantation than in the other stands (p < .05). The Sørensen similarity index of species composition between seed sources and aboveground vegetation were relatively low (<.50). The seeds of various native tree species were common in the seed bank of the plantations, indicating that seed rain and seed bank played an important role in native forest regeneration. We recommend that managers interested in sustainable forestry should take into consideration the presence of existing soil seed bank when developing their management strategies. In addition, with regard to forest regeneration process, we also recommend supplementation of the species composition by direct seeding or planting of desired species.

Ageratina adenophora and Lantana camara in Kailash Sacred Landscape, India: Current distribution and future climatic scenarios through modeling.

The Himalayan region is one of the global biodiversity hotspots. However, its biodiversity and ecosystems are threatened due to abiotic and biotic drivers. One of the major biotic threats to biodiversity in this region is the rapid spread of Invasive Alien Species (IAS). Natural forests and grasslands are increasingly getting infested by IAS affecting regeneration of native species and decline in availability of bio-resources. Assessing the current status of IAS and prediction of their future spread would be vital for evolving specific species management interventions. Keeping this in view, we conducted an in-depth study on two IASs, viz., Ageratina adenophora and Lantana camara in the Indian part of Kailash Sacred Landscape (KSL), Western Himalaya. Intensive field surveys were conducted to collect the presence of A. adenophora (n = 567) and L. camara (n = 120) along an altitudinal gradient between 300 and 3000 m a.s.l. We performed Principal Component Analysis to nullify the multi-colinearity effects of the environmental predictors following MaxEnt species distribution model in the current and future climatic scenarios for both the species. All current and future model precision (i.e., Area Under the Curve; AUC) for both species was higher than 0.81. It is predicted that under the current rate of climate change and higher emission (i.e., RCP 8.5 pathway), A. adenophora will spread 45.3% more than its current distribution and is likely to reach up to 3029 m a.s.l., whereas, L. camara will spread 29.8% more than its current distribution range and likely to reach up to 3018 m a.s.l. Our results will help in future conservation planning and participatory management of forests and grasslands in the Kailash Sacred Landscape–India.

Spring protection and watercourse and its relationship with environmental quality in family property, in the Caparaó region of Espírito Santo, Brazil

Inappropriate use and management of land has generated processes of environmental degradation, in which the increasing removal of forest coverage has impaired the hydrological cycle, water and soil quality. The objective of this work is to know the effects of the protection of the spring, and the initial part of its watercourse, on the environmental conditions in a family property. The study was carried out on the property located in the Rainha da Paz Community, in Alegre-ES, using indicators used for environmental monitoring, at the beginning in September 2013 and after one year (September 2014) of the Water Planters Project. The quality indicators used in the evaluation clearly show that the initial situation in the spring APP, and APP around the main watercourse was inadequate, in several indicators mainly due to the occupation of the area with agricultural use, specifically pasture, occurring cattle trampling within a radius of 50 meters of the spring's permanent preservation area, causing soil compaction and silting, showing a high degree of degradation, reflecting the lack of environmental adequacy, thus not complying with current environmental legislation. The project promoted improvements in the environmental conditions of the family property, through the natural regeneration of native species, bringing gains to the floristic composition, in addition to improvements in the soil conditions.

Storage duration, light, temperature, and salinity exposure influence germination of the glycophyte Rhanterium epapposum

Regeneration of native species is the first priority for biodiversity conservation and restoration. To this end, it is key to have seeds properly conserved in seed banks and knowledge of seed longevity and (or) dormancy alleviation at different storage time intervals. In addition, understanding the germination response of the stored seeds to environmental conditions improves the efficiency of restoration and rehabilitation projects. We investigated the influence of storage duration (1–5 years), light (0 or 12 h of illumination), thermoperiod (night/day temperatures of 15/20 and 20/25 °C), and salinity (0, 100, 200. and 400 mmol/L of NaCl) on seed germination of Rhanterium epapposum, a glycophytic species from the Arabian Peninsula. Seeds maintained viability after five years of storage indoors at room temperature. Three years of storage alleviated seed dormancy. Exposure to 12 h light per day and thermoperiods of 15/20 °C enhanced seed germination. The seeds were glycophytic; after-ripened seeds exposed to salinity exhibited reduced rates of germination that did not recover after the salinity was alleviated.

Drivers of Restoration Trajectory of a Community of Regenerant Plants: Natural Regeneration or Tree Seedling?

Tree plantation is the most used technique for ecological restoration, although passive restoration requires a lower investment of resources. This research aimed to compare the composition and structure of the community of regenerant plants in areas under restoration through Assisted Natural Regeneration and mixed native Tree Planting, in the same area. We randomly placed 12 plots of 100 m2 each and sampled all the regenerating individuals found within them. We compared both restoration methods regarding growth pattern, dispersal syndromes, and successional groups. In both methodologies, trees and shrubs were the most abundant growth forms. The pioneer successional class was the most abundant in number of individuals for both treatments. We concluded that the two restoration methods allowed the regeneration of native species. We propose that Assisted Natural Regeneration is a viable restoration strategy, capable of boosting the initial processes of the community, especially in a matrix surrounded by remaining forests.

Monitoreo de la sucesión de especies vegetales leñosas bajo una plantación de Pinus radiata D. Don, en el parque universitario “Francisco Vivar Castro”, provincia de Loja, Ecuador

En los andes del Ecuador existen plantaciones de Pinus radiata y Pinus patula, sembradas entre matorrales, páramos y áreas abiertas; y, se desconoce la sucesión vegetal, sus cambios y desarrollo. Se investigó una plantación de Pinus radiata en la hoya de Loja con el objetivo de caracterizar la composición florística y monitorear la regeneración natural considerando categorías de regeneración: plántulas, brinzales y latizales. Se establecieron 5 parcelas de 20 m x 20 m, se anidaron 5 subparcelas de 5 m x 5 m y 5 subparcelas de 1 m x 1 m. Se midió altura y diámetro basal. Se determinó la sobrevivencia y crecimiento en un periodo de 12 meses; se analizó la influencia de variables ambientales: luminosidad, pendiente, profundidad del suelo horizonte O, sobre la diversidad y abundancia de la regeneración natural. Se identificaron 24 especies, 21 géneros y 22 familias. La mayor diversidad presentan los latizales; las especies con mayor IVI en las tres categorías son: Piper barbatum, Viburnum triphyllum y Frangula granulosa. Los latizales presentan mayor sobrevivencia (99,37 %), seguida por brinzales (87,59 %) y plántulas (82,76 %). El incremento en altura y diámetro es mayor en Frangula granulosa, Clusia latipes, Critoniopsis pycnantha y Alnus acuminata. No existe influencia significativa de los factores ambientales sobre la diversidad y abundancia de la regeneración natural. La regeneración natural encontrada en las condiciones de hábitat de la plantación; demuestra que es factible la recuperación de la vegetación natural y la presencia de un bosque natural cuando desaparezca la plantación forestal.

Forest restoration in the floodplains of the Amazon estuary subjected to intensive açaí management

Abstract The expansion and intensification of açaí management in floodplain forests of the Amazonian estuary have resulted in changes in floristic composition and in biodiversity losses, causing problems to ecosystems and endangering livelihoods of riverine communities. These transformations have prompted the need for forest restoration. The objective of this study was to identify and analyze forest recovery initiatives carried out in floodplain forests previously subjected to intensive açaí management in the Amazonian estuary. Methods included structured interviews and questionnaires. Results reveled the following restoration types: 1) area enrichment: subtype 1 - high floodplain forest (7.89%) and subtype 2 - low floodplain forest (44.75%); 2) directing natural regeneration of native species (34.21%); 3) cultivation of native species (13.15%). Results suggest that forest restoration efforts can promote sustainable production of açaí, productive diversity, ecosystem conservation and generate income for riverine families.

Forest restoration by different nucleation techniques in Urochloa grassland

Abstract: The objective of this work was to evaluate the effect of brushwood, black plastic mulch, herbicide, and artificial perch on the natural regeneration of native species in Urochloa grassland. The experiment was conducted between February 2014 and February 2016 in the Dense Ombrophilous Forest, in the municipality of Morretes, in the state of Paraná, Brazil. The treatments were: herbicide, herbicide + perch, black plastic mulch, black plastic mulch + perch, brushwood + herbicide, brushwood + herbicide + perch, and a control treatment. The evaluations were carried out at 4, 8, 12, 18, and 24 months after the installation of the experiment, by counting and identifying regenerating woody species and estimating visually the percentage of herbaceous coverage. Initially, brushwood and black plastic mulch reduced the Urochloa grasses; however, this effect was lost over time due to the rapid growth of the grasses from the edges to the center of the plots. The use of perches in the treatments does not allow a significant increase of other species because of the continued inhibiting conditions for the establishment of seedlings. The herbicide is effective in removing the grasses; however, the recruitment of woody species is only satisfactory when perches are used to attract the dispersing fauna. For a successful ecological restoration of pastures, there is a need for the local elimination of Urochloa grasses.

Ecological succession in areas degraded by bauxite mining indicates successful use of topsoil

Brazilian ironstone outcrops (cangas) are nutrient‐poor stressful habitat dominated by slow‐growing woody species with high biodiversity and unique evolutionary history. Mining has produced great impacts on this ecosystem. Spontaneous regeneration of abandoned canga mined areas has not been observed. One of the active methods most widely used for ecological restoration in environments where soil has been lost or severely degraded is topsoil transposition due to the physical, chemical, and microbiological improvement of the substrate, in addition to the seed bank. Thus, plant succession was monitored for 40 months after topsoil transposition in a canga area degraded by aluminum mining, without any other type of management. A completely randomized design with 70 permanent plots (1 × 1 m) was used. Annual phytosociological surveys were carried out and floristic and vegetational spectra were constructed with the life‐forms proposed by Raunkiaer. Floristic composition was compared with a reference site. Overall, 105 species were identified. Both flora and vegetation changed over time, increasing resemblance to the reference areas. The floristic and vegetational spectra after 4 years of topsoil deposition are similar to pristine ones. The vegetation spectrum showed an increase in the dominance of phanerophytes and hemicryptophytes, while therophytes reduced their proportion. The early successional stage is dominated by weeds, like in other canga restoration studies, but did not impede the native species regeneration. Cangas's species recruited well from transposed topsoil. Unlike other studies with fertilized topsoil, our findings show the efficiency of topsoil transposition to provide initial conditions for the ecological restoration of this ecosystem.