The current Tanzanian policy guidelines regarding ecological restoration encourage total protection (enclosure system) against grazing activities, fires and wood extraction to allow regeneration in state-based Miombo ...The current Tanzanian policy guidelines regarding ecological restoration encourage total protection (enclosure system) against grazing activities, fires and wood extraction to allow regeneration in state-based Miombo woodlands. However, there is little evidence on how such treatments would promote restoration. We fetched the pieces of evidence from studies that evaluated the impact of management treatments on the lightly degraded Miombo woodlands at Kitulangalo Forest Reserve in eastern Tanzania. Plot fencing and fire exclusion constrained woody species regeneration due to competition compared to unfenced plots. Adopting quota grazing policies and controlled burning systems can be the shortest and most eco-friendly pathways towards Miombo restoration. The results pointed out that stand disturbances and silvicultural practices can promote regeneration, which is crucial to promoting ecological restoration in Miombo woodlands.展开更多
The Woodlands,是Ian McHarg最有影响力的项目之一,是美国历史上第一座以生态学理论为主导的新城规划。以采用生态水文设计、原生植物保护、建立野生动物廊道等生态学方法而闻名。该城的建设在维持城市自然景观格局、保护生物栖息地及...The Woodlands,是Ian McHarg最有影响力的项目之一,是美国历史上第一座以生态学理论为主导的新城规划。以采用生态水文设计、原生植物保护、建立野生动物廊道等生态学方法而闻名。该城的建设在维持城市自然景观格局、保护生物栖息地及预防雨洪等方面堪称典范,对我国城市雨洪管理和风景园林设计具有借鉴价值。展开更多
This study in the dry tropical woodlands of SE Angola in Cuando-Cubango Province assessed the diversity and composition of woody species in fallows compared to those in mature woodlands. We assessed the population str...This study in the dry tropical woodlands of SE Angola in Cuando-Cubango Province assessed the diversity and composition of woody species in fallows compared to those in mature woodlands. We assessed the population structure of the most harvested woody species by calculating size class distribution and evaluated their regeneration potential based on the density of saplings. The vegetation was surveyed in 20 plots of 20 × 50 m(1000 m2). In each plot, we measured the diameter at breast height(DBH) of all woody species with DBH ≥ 5 cm. The saplings were counted, identified and recorded; 718 individuals, corresponding to 34 species in 32 genera and 15 families were recorded. The size class distribution of target woody species showed three different patterns in fallows and mature woodlands. In general,most of the smaller diameter classes had more individuals than the larger ones did, showing that the regeneration may take place. However, in some diameter classes, the absence of larger stems indicated selective logging of larger trees. Few saplings were recorded in the fallows or mature woodlands; fire frequency and intensity is probably the main obstacle for seed germination and seedling survival rates in the studied area.展开更多
Populations of Acer grandidentatum Nutt. (Bigtooth maple, Aceraceae = Sapindaceae) in central Texas are mostly found in isolated, deep, relatively remote, limestone canyons. Acer grandidentatum is found with a few oth...Populations of Acer grandidentatum Nutt. (Bigtooth maple, Aceraceae = Sapindaceae) in central Texas are mostly found in isolated, deep, relatively remote, limestone canyons. Acer grandidentatum is found with a few other mostly deciduous species. Recruitment of juveniles has been reported to be lacking. One population of A. grandidentatum juveniles was found in a limestone canyon in a State Natural Area in Central Texas. Fifty juveniles were located. Wire enclosures were placed around half of the seedlings with half left in the open. In an adjacent canyon, 50 juvenile seedlings were planted in a similar habitat with adult A. grandidentatum trees nearby. Half were in enclosures and half in the open. Plant survival was followed for four growing seasons until November 2019. At the end of that time when survivals were compared between plants in enclosures and those in the open in both canyon communities, there was a significant difference in survival in both communities (χ2, P < 0.001). Survival in the planted population in enclosures was 92% with 52% in the open. In the natural population in enclosures 68% survived, with 32% survivals in the open. When population extinction was compared, extinction for planted juveniles in enclosures using linear regression was 60.5 yrs and it was 11.9 yrs in the open. For native juveniles, it was 12.6 yrs in enclosures and 5.9 yrs in the open. The cause of most mortalities in the open seemed to be herbivory by white-tailed deer (Odocoleus virginianus).展开更多
Forest assessments are essential to understand the tree population structure and diversity status of forests and to provide information for biodiversity recovery planning. Unfortunately, the majority of Miombo woodlan...Forest assessments are essential to understand the tree population structure and diversity status of forests and to provide information for biodiversity recovery planning. Unfortunately, the majority of Miombo woodlands in Mozambique lack of inventory data, and consequently are often insufficient for management. This study aimed to assess the species richness, diversity and structure of Miombo woodlands using a range of sampling sizes in Mocuba district, Mozambique. Plant inventory was carried out in 128 systematically selected sample plots in 71.6 ha, which was divided into eight treatments, i.e., TI： 0.1 ha; T2：0.25 ha; T3：0.375 ha; T4：0.5 ha; T5：0.625 ha; T6：0.75 ha; T7：0.875 ha; T8：1.0 ha, with 16 repetitions. All stems _〉 10 cm diameter at breast height, and species name to evaluate the floristic composition, richness of tree species, diversity and diameter distribution were recorded. A total of 36,535 individuals were recorded, belonging 124 species, 83 genera and representing 31 botanical families. The most important species was the Brachystegia spiciformis Benth. and the richest botanical family was Fabaceae. The forest showed an average of 517 ＋ 85 trees/ha, and high species diversity and evenness. Analysis of covariance shows that the intercepts and slope of exponential function for diameter distribution are not significantly different for the eight treatments. Compared with the entire composite forest, inventory means were accurately estimated and size class distributions were well represented for plots 〈 0.25 ha, for selecting an efficient sampling design suited to forest characteristics and the inventory＇s purpose.展开更多
We studied woodland vegetation in broad-leaved deciduous woodlands of Metema in northwestern Amhara regional state, Ethiopia Our objective was to describe plant species composition, diversity, re- generation status, a...We studied woodland vegetation in broad-leaved deciduous woodlands of Metema in northwestern Amhara regional state, Ethiopia Our objective was to describe plant species composition, diversity, re- generation status, and population structure by a selective approach with a systematic sampling design. A total of 74 quadrats （each for 25 m x 25 m, spaced at intervals of 150--200 m） were sampled along established tran- sect lines following the homogeneity of the vegetation. Vegetation data including cover-abundance, height, diameter at breast height （DBH）, and numbers of seedlings and saplings of woody species were analyzed using Excel spreadsheet, Shannon Weiner diversity index, and PAST version 1.62. A total of 87 vascular plant species of 74 genera and 36 families were recorded. The dominant family was Fabaceae represented by 16 （18.39 %） species of 13 genera. Shannon Weiner diversity and evenness were 3.67 and 0.82, respectively, which showed that the area was en- dowed with rich floral diversity evenly distributed. The vegetation structure, as quantified by cumulative diameter class frequency distribution, plotted as an interrupted inverted-J- shape pattern with a sharp decrease in the 2nd diameter class. This indicated poor vegetation structure. The diameter classes frequency distributions of selected species plotted in four general patterns i.e., interrupted Inverted-J-shape, J-shape, Bell-shape and Irregular-shape. In conclusion, although the area showed high floral diversity and evenness, woody species including Sterculea setigera, Boswellia papyrifera, and Pterocarpus lucens showed lowest recruitment of seedlings and saplings.展开更多
Elm （Ulmus pumila）, widely distributed in the north temperate zone, contributes to a special savanna-like woodland in typical grassland region in the northeastern China. This woodland performs a variety of ecologica...Elm （Ulmus pumila）, widely distributed in the north temperate zone, contributes to a special savanna-like woodland in typical grassland region in the northeastern China. This woodland performs a variety of ecological functions and environmental signifi- cance, such as decreasing soil erosion, stabilizing sand dunes, preserving species diversity. However, in the last approximate 30 years, the species composition, productivity and distribution area of elm woodland has decreased severely. A series of studies have been carried out to find out whether the climate changes or human disturbances caused the degradation of elm woodland and how these factors af- fected elm woodland. In this study, undisturbed, plowing and grazing elm woodland were investigated in 1983 and 2011 by using Point-Centered Quarter method. The relationship between vegetation changes and environmental factors was analyzed by Bray-Curtis ordination. The results show that in 2011, species diversity and understory productivity of undisturbed elm woodland decrease slightly compared to those of undisturbed elm woodland in 1983. However, nearly 60% of the species is lost in the plowing and grazing elm woodland relative to the species undisturbed elm woodland in 1983. Interestingly, plowing stimulates the growth of elm and certain understory species through furrowing soil and accelerating soil nutrient turnover rate. Grazing disturbance not only leads to species loss and productivity decrease, but also induces changes in elm growth （small, short and twisted）. The mean age of the elm was 29 -4- 2 yr in undisturbed and plowing elm woodland, while only 15 yr in the grazing elm woodland. The results of Bray-Curtis ordination analysis show that all sample stands clustered to three groups： Group I including the undisturbed sample stands of 83UE （undisturbed elm wood- land in 1983） and l lUE （undisturbed elm woodland in 2011）; Group II including sample stands of PE （elm woodland disturbed by plowing）; Group III including samples stands of GE （elm woodland disturbed by grazing）. The results indicate that the long time distur- bance of the plowing and grazing have converted elm woodland to different community types. Climate change is not the primary reason causing the degradation of elm woodland, but plowing and grazing disturbance. Both plowing and grazing decrease the vegetation composition and species diversity. Grazing further decreases vegetation productivity and inhibits the growth of elm tree. Therefore, we suggest that reasonable plowing and exclusive grazing would be favorable for future regeneration of degraded elm woodland.展开更多
The efficiency of sample-based indices proposed to quantify the spatial distribution of trees is influenced by the structure of tree stands, environmental heterogeneity and degree of aggregation. We evaluated 10 commo...The efficiency of sample-based indices proposed to quantify the spatial distribution of trees is influenced by the structure of tree stands, environmental heterogeneity and degree of aggregation. We evaluated 10 commonly used distance-based and 10 density-based indices using two structurally different stands of wild pistachio trees in the Zagros woodlands, Iran, to assess the reliability of each in revealing stand structure in woodlands. All trees were completely stem-mapped in a nearly pure（40 ha） and a mixed（45 ha） stand. First, the inhomogeneous pair correlation function [g（r）] and the Clark-Evans index（CEI） were used as references to reveal the true spatial arrangement of all trees in these stands. The sampled data were then evaluated using the 20 indices.Sampling was undertaken in a grid based on a square lattice using square plots（30 m 9 30 m） and nearest neighbor distances at the sample points. The g（r） and CEI statistics showed that the wild pistachio trees were aggregated in both stands, although the degree of aggregation was markedly higher in the pure stand. Three distance- and six density-based indices statistically verified that the wild pistachio trees were aggregated in both stands. The distance-based Hines and Hines statistic（ht） and the densitybased standardised Morisita（Ip）, patchiness（IP） and Cassie（CA） indices revealed aggregation of the trees in the two structurally different stands in the Zagros woodlands and the higher clumping in the pure stand, whereas the other indices were not sensitive enough.展开更多
Despite the ecological and economic importance of Acacia senegal, little is known about the effects of anthropogenic disturbances on its natural regeneration patterns and population structure. We investigated the effe...Despite the ecological and economic importance of Acacia senegal, little is known about the effects of anthropogenic disturbances on its natural regeneration patterns and population structure. We investigated the effects of these factors within the Lake Baringo woodland ecosystem. Data was collected from 60 plots of 20 m × 20 m systematically distributed in four A. senegal-dominated populations within the Lake Baringo woodland. Sample populations spanned a degradation gradient measured by a population disturbance index (PDI). Trees were measured for diameter at breast height (DBH) and categorized by growth stages: seedling, sapling and adult tree. Higher seedling and sapling densities were recorded in lightly than heavily disturbed populations, but only sapling density was significantly different between the two disturbance levels (P = 0.02). Lightly disturbed populations revealed a reversed J-shape size-class distribution (SCD) indicative of stable structure unlike the heavily disturbed populations. The quotient and permutation indices indicated unstable populations with episodic recruitment and mortality. Our study reveals that natural regeneration and population structure of A. senegal were affected majorly by selective harvesting and heavy browsing. Suitable management strategies to control livestock grazing and illegal tree harvesting within the woodland is required to promote conservation of the species genetic resources展开更多
Savanna woodlands in Sudan host great biodiversity, provide a plethora of ecosystem goods and services to local communities, and sustain numerous ecological functions. Although the importance of the Acacia trees in th...Savanna woodlands in Sudan host great biodiversity, provide a plethora of ecosystem goods and services to local communities, and sustain numerous ecological functions. Although the importance of the Acacia trees in these areas is well known, up-to-date information about these woodlands' diversity is limited and changes in their woody vegetation composition, density, diversity and relative frequency are not monitored over time. This study explored tree diversity and stand stage structure in Nuara Reserved Forest, a typical savanna woodland ecosystem in southeastern Sudan. A total of 638 circular sample plots(1000 m^2 for each) were established using a systematic sampling grid method. The distance between plots was 200 m. In each plot, all living trees with diameter at breast height(DBH) ≥5.00 cm were identified and counted, and their DBH values were recorded. From these data, tree composition, diversity, density and stage structure were assessed. There were 12,259 individual trees representing four species(Acacia seyal, Balanites aegyptiaca, Acacia Senegal and Acacia mellifera) that belong to two families. The dominant species was Acacia seyal. Average tree density was 191 trees/hm^2 and the Shannon-Weiner index for trees diversity was 0.204. Overall, young trees comprised 86.30% of the forest. The state of tree richness and density in the study area was low compared to other similar environments in the region and around the world. We recommended adoption of a proper management system that includes monitoring of woody vegetation diversity in this forest, and management actions to enhance tree diversity and sustain ecosystem services to local communities. In addition to care for the dominant Acacia seyal stands, more attention and conservation should be devoted to reestablishing Acacia senegal and Acacia mellifera trees because of their high ecological and economic values for local communities.展开更多
Background: Modelling aboveground biomass(AGB) in forest and woodland ecosystems is critical for accurate estimation of carbon stocks. However, scarcity of allometric models for predicting AGB remains an issue that ha...Background: Modelling aboveground biomass(AGB) in forest and woodland ecosystems is critical for accurate estimation of carbon stocks. However, scarcity of allometric models for predicting AGB remains an issue that has not been adequately addressed in Africa. In particular, locally developed models for estimating AGB in the tropical woodlands of Ghana have received little attention. In the absence of locally developed allometric models, Ghana will continue to use Tier 1 biomass data through the application of pantropic models. Without local allometric models it is not certain how Ghana would achieve Tier 2 and 3 levels under the United Nations programme for reducing emissions from deforestation and forest degradation. The objective of this study is to develop a mixedspecies allometric model for use in estimating AGB for the tropical woodlands in Ghana. Destructive sampling was carried out on 745 trees(as part of charcoal production) for the development of allometric equations. Diameter at breast height(dbh, i.e. 1.3 m above ground level), total tree height(H) and wood density(ρ) were used as predictors for the models. Seven models were compared and the best model selected based on model efficiency,bias(%) and corrected Akaike Information Criterion. The best model was validated by comparing its results with those of the pantropic model developed by Chave et al.(Glob Chang Biol 20:3177–3190, 2014) using equivalence test and conventional paired t-test.Results: The results revealed that the best model for estimating AGB in the tropical woodlands is AGB =0.0580ρ((dbh)2 H)0.999. The equivalence test showed that this model and the pantropic model developed by Chave et al.(Glob Chang Biol 20:3177–3190, 2014) were equivalent within ±10% of their mean predictions(p-values <0.0001 for one-tailed t-tests for both lower and upper bounds at 5% significant level), while the paired t-test revealed that the mean(181.44 ± 18.25 kg) of the model predictions of the best model of this study was significantly(n = 745, mean diff. = 16.50 ± 2.45 kg;S.E. = 1.25 kg;p < 0.001) greater than that(164.94 ± 15.82 kg) of the pantropic model of Chave et al.(Glob Chang Biol 20:3177–3190, 2014).Conclusion: The model developed in this study fills a critical gap in estimating AGB in tropical woodlands in Ghana and other West African countries with similar ecological conditions. Despite the equivalence with the pantropic model it remains superior to the model of Chave et al.(Glob Chang Biol 20:3177–3190, 2014) for the estimation of AGB in local tropical woodlands. It is a relevant tool for the attainment of Tier 2 and 3 levels for REDD+. The model is recommended for use in the tropical woodlands in Ghana and other West African countries in place of the use of pantropic models.展开更多
The Miombo ecoregion covers eastern and southern Africa,with variations in plant species composition,structure,and biomass across a broad precipitation gradient.Most studies of woody plant communities focus exclusivel...The Miombo ecoregion covers eastern and southern Africa,with variations in plant species composition,structure,and biomass across a broad precipitation gradient.Most studies of woody plant communities focus exclusively on larger overstorey trees(≥5 or≥10cm stem diameter),overlooking the contribution of small trees and shrubs in the understorey,which can comprise a significant portion of total biomass and diversity.Here,we evaluate the contribution of both large overstorey and small understorey woody plants to species diversity and above-ground biomass(AGB),with 17 plots(0.5-1ha)across five sites representing both extremes of rainfall gradient spanning the Miombo ecoregion,in northeast Namibia(500-700mm mean annual precipitation,MAP)and southern Democratic Republic of Congo(DRC)(>1,200mm MAP).Mean AGB per site ranged from 21 to 119Mg·ha^(-1),increasing with rainfall,while the proportional AGB contribution of small trees,saplings,and shrubs decreased.In dry Namibia,small trees,saplings,and shrubs(<5cm DBH)contributed up to 28.2%of total AGB(mean±standard deviation:18.3%±3.4%),whereas in wet DRC,they contributed only up to 2.5%(2.3%±1.4%).Namibian sites,on average,contained a large proportion of woody species diversity exclusively in small trees and shrubs(<5cm DBH),with 55 species representing 59.4%of the total diversity.In contrast,DRC sites had higher overall small woody plant diversity(66 species)but fewer species found exclusively as small individuals(25.2%),with many saplings that grow to larger trees.Understorey composition also differed,with saplings of overstorey trees dominating in DRC,while shrubs dominated in Namibia.Our findings show that woody biomass and diversity in dry woodlands are substantially underestimated when studies focus only on larger trees.This highlights the need to consider all woody vegetation to better understand woody plant diversity and biomass variation.展开更多
The Eurasian beaver(Castor fiber Linnaeus,1758)can be considered a hydrological ecosystem engineer as it shapes environmental characteristics through its building activities and feeding behaviour.Even if several studi...The Eurasian beaver(Castor fiber Linnaeus,1758)can be considered a hydrological ecosystem engineer as it shapes environmental characteristics through its building activities and feeding behaviour.Even if several studies have so far reported beaver impact on multi-taxon biodiversity and forest regeneration,there is a lack of research on forest stand structure evolution following beaver direct activity on trees.This represents a pivotal topic for predicting restoration outcomes and reccommending sound silvicultural and management practices to maintain specific forest conditions.Specifically,the study aims at investigating forest stand structure and tree species diversity changes considering river variability,distance from the riverbank and beaver's gnawing activity intensity.The Eurasian beaver is only recently recolonising the three analysed Mediterranean rivers,but stand structure seems to be already significantly impacted by the species.The number of trees was reduced,increasing mean diameter at breast height at stand level,as most of the youngest and/or smaller trees are entirely cut down.Strongest structural variations can be detected in intensively impacted stands and in the forest portions closer to the riverbank.The absence of a significant effect on most of the diversity indices is likely due to the initially homogeneous composition of the tree layer in each stand and to the limited variety of beaver's diet within the sites.Future resprouting of secondary tree shoots,as well as beaver gnawing activity changes in intensity over time and space,can further produce variations in structural parameters and woody species diversity in the medium-and long-term period.Therefore,it will be crucial to further monitor the long-term effects,as structural shifts can produce significant effects on riparian ecosystem functions.展开更多
We explored if and how seasonal fires interact with microhabitat type(i.e.under Pistacia shrub,under Cistus shrub or a canopy gap)to influence the composition of the germinable soil seed bank(GSSB)community in a typic...We explored if and how seasonal fires interact with microhabitat type(i.e.under Pistacia shrub,under Cistus shrub or a canopy gap)to influence the composition of the germinable soil seed bank(GSSB)community in a typical eastern Mediterranean woodland.We conducted a field experiment,involving prescribed spring and autumn burns,and thereafter quantified the seed germination patterns using soil samples collected from both burned and adjacent unburned control plots.Soil temperature was significantly higher during autumn burns,while being more variable during spring burns.Fire caused overall reductions in GSSB density,richness and diversity.The reductions in GSSB richness and diversity were significantly stronger under Pistacia and Cistus shrubs located within plots subjected to autumn burns,and these patterns were mainly evident among annuals.GSSB density of dwarf shrubs was higher in samples collected from burned plots,and this pattern was more pronounced in samples collected under Pistacia and Cistus shrubs.Together with the appearance of unique species,seasonal fires led to significant changes in the composition of the GSSB community.Our results illustrate that seasonal fires interact with spatial heterogeneity to influence the composition of the GSSB community mostly via differential effects on the germination densities of annuals and dwarf shrubs.These findings imply that the increase in the frequency of seasonal fires,which has occurred in the eastern Mediterranean basin during the last few decades,may translate into a shift in eco-evolutionary selection pressures,operating on plants inhabiting this unique ecosystem.展开更多
Aims Given the key functional role of understorey plant communities and the substantial extent of forest cover at the global scale,investigating understorey community responses to elevated CO_(2)(eCO_(2))concentration...Aims Given the key functional role of understorey plant communities and the substantial extent of forest cover at the global scale,investigating understorey community responses to elevated CO_(2)(eCO_(2))concentrations,and the role of soil resources in these responses,is important for understanding the ecosystem-level consequences of rising CO_(2)concentrations for forest ecosystems.Here,we evaluated how experimentally manipulating the availabilities of the two most limiting resources in an extremely phosphorus-limited eucalypt woodland in eastern Australia(i.e.water and phosphorus)can modulate the response of the understorey community to eCO_(2)in terms of germination,phenology,cover,community composition and leaf traits.Methods We collected soil containing native soil seed bank to grow experimental understorey plant communities under glasshouse conditions.Important Findings Phosphorus addition increased total plant cover,particularly during the first 4 weeks of growth and under high water conditions,a response driven by the graminoid component of the plant community.However,the treatment differences diminished as the experiment progressed,with all treatments converging at〜80%lant cover after〜11 weeks.In contrast,plant cover was not affected by eCO_(2).Multivariate analyses reflected temporal changes in the composition of plant communities,from pots where bare soil was dominant to high-cover pots dominated by a diverse community.However,both phosphorus addition and the interaction between water availability and CO_(2)affected the temporal trajectory of the plant community during the experiment.eCO_(2)also increased community-level specific leaf area,suggesting that functional adaptation of plant communities to CO_(2)may precede the onset of compositional responses.Given that the response of our seed bank-derived understorey community to CO_(2)developed over time and was mediated by interactions with phosphorus and water availability,our results suggest a limited role of eCO_(2)in shaping plant communities in water-limited systems,particularly where low soil nutrient availability constrains productivity responses.展开更多
Trees provide multiple ecosystem services such as carbon sequestration,hydrological regulation and habitat for arboreal animals.However,they are often removed to support agricultural enterprises.Despite the importance...Trees provide multiple ecosystem services such as carbon sequestration,hydrological regulation and habitat for arboreal animals.However,they are often removed to support agricultural enterprises.Despite the importance of tree remnants,we know relatively little about how soils differ across sites of varying condition.Here,we describe a study where we examined the relative effects of trees,compared with unvegetated interspaces,on soil functions in remnant patches at sites in good and poor condition in two eucalypt communities in an irrigation area in eastern Australia.We found that,in general,carbon and nutrient cycling were relatively greater beneath trees,and in surface soils,but there were no clear trends in relation to site condition.The values of most soil attributes(e.g.,soluble and exchangeable cations,nitrogen,phosphorus)were greater beneath trees,indicating strong fertile island effects in both communities.Overall,our study confirms the importance of trees in remnant patches in agricultural landscapes,particularly those in sites of poor condition.It also suggests that soil processes may still be relatively intact,even in sites in poor condition.Our study reinforces the need to protect trees in remnant woodland reserves to maintain critical ecosystem functions related to nutrient retention.These remnants are important for achieving sustainable management of agricultural systems.展开更多
Honghuagang District,Zunyi City,Guizhou Province,develops the characteristic industry of crispy peaches,and at the same time develops the forest economy and promotes the model of planting soybeans in peach orchards to...Honghuagang District,Zunyi City,Guizhou Province,develops the characteristic industry of crispy peaches,and at the same time develops the forest economy and promotes the model of planting soybeans in peach orchards to promote rural revitalization.However,due to the different pests and diseases occurring in peach trees and soybeans,the control drugs used are also different,and the existing technology for spraying and controlling peach or soybean seedlings is operated separately and cannot be sprayed together at the same time.This study,based on the actual situation of forest land,develops a spraying device for interplantation in forest(peach tree and soybean)from the aspects of technical solutions,working principles and beneficial effects,in order to solve the problem of low spraying efficiency of spraying control of peach tree or soybean seedlings in the existing technology.展开更多
There is an increasing interest in restoring degraded forests,which occupy half of the forest areas.Among the forms of restoration,passive restoration,which involves the elimination of degrading factors and the free e...There is an increasing interest in restoring degraded forests,which occupy half of the forest areas.Among the forms of restoration,passive restoration,which involves the elimination of degrading factors and the free evolution of natural dynamics by applying minimal or no management,is gaining attention.Natural dynamics is difficult to predict due to the influence of multiple interacting factors such as climatic and edaphic conditions,composition and abundance of species,and the successional character of these species.Here,we study the natural dynamics of a mixed forest located in central Spain,which maintained an open forest structure,due to intensive use,until grazing and cutting were banned in the 1960s.The most frequent woody species in this forest are Fagus sylvatica,Quercus petraea,Quercus pyrenaica,Ilex aquifolium,Sorbus aucuparia,Sorbus aria and Prunus avium,with contrasting shade and drought tolerance.These species are common in temperate European deciduous forest and are found here near their southern distribution limit,except for Q.pyrenaica.In order to analyze forest dynamics and composition,three inventories were carried out in 1994,2005 and 2015.Our results show that,despite the Mediterranean influence,the natural dynamics of this forest has been mainly determined by different levels of shade tolerance.After the abandonment of grazing and cutting,Q.pyrenaica expanded rapidly due to its lower shade tolerance,whereas after canopy closure and forest densification,shade-tolerant species gained ground,particularly F.sylvatica,despite its lower drought and late-frost tolerance.If the current dynamics continue,F.sylvatica will overtake the rest of the species,which will be relegated to sites with shallow soils and steep slopes.Simultaneously,all the multi-centennial beech trees,which are undergoing a rapid mortality and decline process,will disappear.展开更多
文摘The current Tanzanian policy guidelines regarding ecological restoration encourage total protection (enclosure system) against grazing activities, fires and wood extraction to allow regeneration in state-based Miombo woodlands. However, there is little evidence on how such treatments would promote restoration. We fetched the pieces of evidence from studies that evaluated the impact of management treatments on the lightly degraded Miombo woodlands at Kitulangalo Forest Reserve in eastern Tanzania. Plot fencing and fire exclusion constrained woody species regeneration due to competition compared to unfenced plots. Adopting quota grazing policies and controlled burning systems can be the shortest and most eco-friendly pathways towards Miombo restoration. The results pointed out that stand disturbances and silvicultural practices can promote regeneration, which is crucial to promoting ecological restoration in Miombo woodlands.
基金supported by The Future Okavango Project(Grant Number(01LL0912A))
文摘This study in the dry tropical woodlands of SE Angola in Cuando-Cubango Province assessed the diversity and composition of woody species in fallows compared to those in mature woodlands. We assessed the population structure of the most harvested woody species by calculating size class distribution and evaluated their regeneration potential based on the density of saplings. The vegetation was surveyed in 20 plots of 20 × 50 m(1000 m2). In each plot, we measured the diameter at breast height(DBH) of all woody species with DBH ≥ 5 cm. The saplings were counted, identified and recorded; 718 individuals, corresponding to 34 species in 32 genera and 15 families were recorded. The size class distribution of target woody species showed three different patterns in fallows and mature woodlands. In general,most of the smaller diameter classes had more individuals than the larger ones did, showing that the regeneration may take place. However, in some diameter classes, the absence of larger stems indicated selective logging of larger trees. Few saplings were recorded in the fallows or mature woodlands; fire frequency and intensity is probably the main obstacle for seed germination and seedling survival rates in the studied area.
文摘Populations of Acer grandidentatum Nutt. (Bigtooth maple, Aceraceae = Sapindaceae) in central Texas are mostly found in isolated, deep, relatively remote, limestone canyons. Acer grandidentatum is found with a few other mostly deciduous species. Recruitment of juveniles has been reported to be lacking. One population of A. grandidentatum juveniles was found in a limestone canyon in a State Natural Area in Central Texas. Fifty juveniles were located. Wire enclosures were placed around half of the seedlings with half left in the open. In an adjacent canyon, 50 juvenile seedlings were planted in a similar habitat with adult A. grandidentatum trees nearby. Half were in enclosures and half in the open. Plant survival was followed for four growing seasons until November 2019. At the end of that time when survivals were compared between plants in enclosures and those in the open in both canyon communities, there was a significant difference in survival in both communities (χ2, P < 0.001). Survival in the planted population in enclosures was 92% with 52% in the open. In the natural population in enclosures 68% survived, with 32% survivals in the open. When population extinction was compared, extinction for planted juveniles in enclosures using linear regression was 60.5 yrs and it was 11.9 yrs in the open. For native juveniles, it was 12.6 yrs in enclosures and 5.9 yrs in the open. The cause of most mortalities in the open seemed to be herbivory by white-tailed deer (Odocoleus virginianus).
文摘Forest assessments are essential to understand the tree population structure and diversity status of forests and to provide information for biodiversity recovery planning. Unfortunately, the majority of Miombo woodlands in Mozambique lack of inventory data, and consequently are often insufficient for management. This study aimed to assess the species richness, diversity and structure of Miombo woodlands using a range of sampling sizes in Mocuba district, Mozambique. Plant inventory was carried out in 128 systematically selected sample plots in 71.6 ha, which was divided into eight treatments, i.e., TI： 0.1 ha; T2：0.25 ha; T3：0.375 ha; T4：0.5 ha; T5：0.625 ha; T6：0.75 ha; T7：0.875 ha; T8：1.0 ha, with 16 repetitions. All stems _〉 10 cm diameter at breast height, and species name to evaluate the floristic composition, richness of tree species, diversity and diameter distribution were recorded. A total of 36,535 individuals were recorded, belonging 124 species, 83 genera and representing 31 botanical families. The most important species was the Brachystegia spiciformis Benth. and the richest botanical family was Fabaceae. The forest showed an average of 517 ＋ 85 trees/ha, and high species diversity and evenness. Analysis of covariance shows that the intercepts and slope of exponential function for diameter distribution are not significantly different for the eight treatments. Compared with the entire composite forest, inventory means were accurately estimated and size class distributions were well represented for plots 〈 0.25 ha, for selecting an efficient sampling design suited to forest characteristics and the inventory＇s purpose.
文摘We studied woodland vegetation in broad-leaved deciduous woodlands of Metema in northwestern Amhara regional state, Ethiopia Our objective was to describe plant species composition, diversity, re- generation status, and population structure by a selective approach with a systematic sampling design. A total of 74 quadrats （each for 25 m x 25 m, spaced at intervals of 150--200 m） were sampled along established tran- sect lines following the homogeneity of the vegetation. Vegetation data including cover-abundance, height, diameter at breast height （DBH）, and numbers of seedlings and saplings of woody species were analyzed using Excel spreadsheet, Shannon Weiner diversity index, and PAST version 1.62. A total of 87 vascular plant species of 74 genera and 36 families were recorded. The dominant family was Fabaceae represented by 16 （18.39 %） species of 13 genera. Shannon Weiner diversity and evenness were 3.67 and 0.82, respectively, which showed that the area was en- dowed with rich floral diversity evenly distributed. The vegetation structure, as quantified by cumulative diameter class frequency distribution, plotted as an interrupted inverted-J- shape pattern with a sharp decrease in the 2nd diameter class. This indicated poor vegetation structure. The diameter classes frequency distributions of selected species plotted in four general patterns i.e., interrupted Inverted-J-shape, J-shape, Bell-shape and Irregular-shape. In conclusion, although the area showed high floral diversity and evenness, woody species including Sterculea setigera, Boswellia papyrifera, and Pterocarpus lucens showed lowest recruitment of seedlings and saplings.
基金Under the auspices of the Seventh Framework Programme(European Commission,No.226818)National Natural Science Foundation of China(No.31070294,31072070,31100331)
文摘Elm （Ulmus pumila）, widely distributed in the north temperate zone, contributes to a special savanna-like woodland in typical grassland region in the northeastern China. This woodland performs a variety of ecological functions and environmental signifi- cance, such as decreasing soil erosion, stabilizing sand dunes, preserving species diversity. However, in the last approximate 30 years, the species composition, productivity and distribution area of elm woodland has decreased severely. A series of studies have been carried out to find out whether the climate changes or human disturbances caused the degradation of elm woodland and how these factors af- fected elm woodland. In this study, undisturbed, plowing and grazing elm woodland were investigated in 1983 and 2011 by using Point-Centered Quarter method. The relationship between vegetation changes and environmental factors was analyzed by Bray-Curtis ordination. The results show that in 2011, species diversity and understory productivity of undisturbed elm woodland decrease slightly compared to those of undisturbed elm woodland in 1983. However, nearly 60% of the species is lost in the plowing and grazing elm woodland relative to the species undisturbed elm woodland in 1983. Interestingly, plowing stimulates the growth of elm and certain understory species through furrowing soil and accelerating soil nutrient turnover rate. Grazing disturbance not only leads to species loss and productivity decrease, but also induces changes in elm growth （small, short and twisted）. The mean age of the elm was 29 -4- 2 yr in undisturbed and plowing elm woodland, while only 15 yr in the grazing elm woodland. The results of Bray-Curtis ordination analysis show that all sample stands clustered to three groups： Group I including the undisturbed sample stands of 83UE （undisturbed elm wood- land in 1983） and l lUE （undisturbed elm woodland in 2011）; Group II including sample stands of PE （elm woodland disturbed by plowing）; Group III including samples stands of GE （elm woodland disturbed by grazing）. The results indicate that the long time distur- bance of the plowing and grazing have converted elm woodland to different community types. Climate change is not the primary reason causing the degradation of elm woodland, but plowing and grazing disturbance. Both plowing and grazing decrease the vegetation composition and species diversity. Grazing further decreases vegetation productivity and inhibits the growth of elm tree. Therefore, we suggest that reasonable plowing and exclusive grazing would be favorable for future regeneration of degraded elm woodland.
基金supported by Vice Chancellor for Research,Shiraz University,IranErasmus Mundus scholarship for travel to Goettingen,Germany
文摘The efficiency of sample-based indices proposed to quantify the spatial distribution of trees is influenced by the structure of tree stands, environmental heterogeneity and degree of aggregation. We evaluated 10 commonly used distance-based and 10 density-based indices using two structurally different stands of wild pistachio trees in the Zagros woodlands, Iran, to assess the reliability of each in revealing stand structure in woodlands. All trees were completely stem-mapped in a nearly pure（40 ha） and a mixed（45 ha） stand. First, the inhomogeneous pair correlation function [g（r）] and the Clark-Evans index（CEI） were used as references to reveal the true spatial arrangement of all trees in these stands. The sampled data were then evaluated using the 20 indices.Sampling was undertaken in a grid based on a square lattice using square plots（30 m 9 30 m） and nearest neighbor distances at the sample points. The g（r） and CEI statistics showed that the wild pistachio trees were aggregated in both stands, although the degree of aggregation was markedly higher in the pure stand. Three distance- and six density-based indices statistically verified that the wild pistachio trees were aggregated in both stands. The distance-based Hines and Hines statistic（ht） and the densitybased standardised Morisita（Ip）, patchiness（IP） and Cassie（CA） indices revealed aggregation of the trees in the two structurally different stands in the Zagros woodlands and the higher clumping in the pure stand, whereas the other indices were not sensitive enough.
基金supported by Kenya Forestry Research Institute(KEFRI/FBEM 2014_2015/2.3)International Foundation for Science(IFS D5452-1)
文摘Despite the ecological and economic importance of Acacia senegal, little is known about the effects of anthropogenic disturbances on its natural regeneration patterns and population structure. We investigated the effects of these factors within the Lake Baringo woodland ecosystem. Data was collected from 60 plots of 20 m × 20 m systematically distributed in four A. senegal-dominated populations within the Lake Baringo woodland. Sample populations spanned a degradation gradient measured by a population disturbance index (PDI). Trees were measured for diameter at breast height (DBH) and categorized by growth stages: seedling, sapling and adult tree. Higher seedling and sapling densities were recorded in lightly than heavily disturbed populations, but only sapling density was significantly different between the two disturbance levels (P = 0.02). Lightly disturbed populations revealed a reversed J-shape size-class distribution (SCD) indicative of stable structure unlike the heavily disturbed populations. The quotient and permutation indices indicated unstable populations with episodic recruitment and mortality. Our study reveals that natural regeneration and population structure of A. senegal were affected majorly by selective harvesting and heavy browsing. Suitable management strategies to control livestock grazing and illegal tree harvesting within the woodland is required to promote conservation of the species genetic resources
文摘Savanna woodlands in Sudan host great biodiversity, provide a plethora of ecosystem goods and services to local communities, and sustain numerous ecological functions. Although the importance of the Acacia trees in these areas is well known, up-to-date information about these woodlands' diversity is limited and changes in their woody vegetation composition, density, diversity and relative frequency are not monitored over time. This study explored tree diversity and stand stage structure in Nuara Reserved Forest, a typical savanna woodland ecosystem in southeastern Sudan. A total of 638 circular sample plots(1000 m^2 for each) were established using a systematic sampling grid method. The distance between plots was 200 m. In each plot, all living trees with diameter at breast height(DBH) ≥5.00 cm were identified and counted, and their DBH values were recorded. From these data, tree composition, diversity, density and stage structure were assessed. There were 12,259 individual trees representing four species(Acacia seyal, Balanites aegyptiaca, Acacia Senegal and Acacia mellifera) that belong to two families. The dominant species was Acacia seyal. Average tree density was 191 trees/hm^2 and the Shannon-Weiner index for trees diversity was 0.204. Overall, young trees comprised 86.30% of the forest. The state of tree richness and density in the study area was low compared to other similar environments in the region and around the world. We recommended adoption of a proper management system that includes monitoring of woody vegetation diversity in this forest, and management actions to enhance tree diversity and sustain ecosystem services to local communities. In addition to care for the dominant Acacia seyal stands, more attention and conservation should be devoted to reestablishing Acacia senegal and Acacia mellifera trees because of their high ecological and economic values for local communities.
基金Federal Ministry of Education and Research (BMBF) of Germany,funded the PhD programme of the lead author through the West African Science Service Centre for Climate Change and Adapted Land use (WASCAL)。
文摘Background: Modelling aboveground biomass(AGB) in forest and woodland ecosystems is critical for accurate estimation of carbon stocks. However, scarcity of allometric models for predicting AGB remains an issue that has not been adequately addressed in Africa. In particular, locally developed models for estimating AGB in the tropical woodlands of Ghana have received little attention. In the absence of locally developed allometric models, Ghana will continue to use Tier 1 biomass data through the application of pantropic models. Without local allometric models it is not certain how Ghana would achieve Tier 2 and 3 levels under the United Nations programme for reducing emissions from deforestation and forest degradation. The objective of this study is to develop a mixedspecies allometric model for use in estimating AGB for the tropical woodlands in Ghana. Destructive sampling was carried out on 745 trees(as part of charcoal production) for the development of allometric equations. Diameter at breast height(dbh, i.e. 1.3 m above ground level), total tree height(H) and wood density(ρ) were used as predictors for the models. Seven models were compared and the best model selected based on model efficiency,bias(%) and corrected Akaike Information Criterion. The best model was validated by comparing its results with those of the pantropic model developed by Chave et al.(Glob Chang Biol 20:3177–3190, 2014) using equivalence test and conventional paired t-test.Results: The results revealed that the best model for estimating AGB in the tropical woodlands is AGB =0.0580ρ((dbh)2 H)0.999. The equivalence test showed that this model and the pantropic model developed by Chave et al.(Glob Chang Biol 20:3177–3190, 2014) were equivalent within ±10% of their mean predictions(p-values <0.0001 for one-tailed t-tests for both lower and upper bounds at 5% significant level), while the paired t-test revealed that the mean(181.44 ± 18.25 kg) of the model predictions of the best model of this study was significantly(n = 745, mean diff. = 16.50 ± 2.45 kg;S.E. = 1.25 kg;p < 0.001) greater than that(164.94 ± 15.82 kg) of the pantropic model of Chave et al.(Glob Chang Biol 20:3177–3190, 2014).Conclusion: The model developed in this study fills a critical gap in estimating AGB in tropical woodlands in Ghana and other West African countries with similar ecological conditions. Despite the equivalence with the pantropic model it remains superior to the model of Chave et al.(Glob Chang Biol 20:3177–3190, 2014) for the estimation of AGB in local tropical woodlands. It is a relevant tool for the attainment of Tier 2 and 3 levels for REDD+. The model is recommended for use in the tropical woodlands in Ghana and other West African countries in place of the use of pantropic models.
基金funded by the following grants:the Natural Environ-ment Research Council-Funded SECO Project(NE/T01279X/1)the Fostering Research&Intra-African Knowledge Transfer Through Mobility&Education(FRAME)Conservation Action Research Network(CARN)through the ASPIRE Grant Programme.
文摘The Miombo ecoregion covers eastern and southern Africa,with variations in plant species composition,structure,and biomass across a broad precipitation gradient.Most studies of woody plant communities focus exclusively on larger overstorey trees(≥5 or≥10cm stem diameter),overlooking the contribution of small trees and shrubs in the understorey,which can comprise a significant portion of total biomass and diversity.Here,we evaluate the contribution of both large overstorey and small understorey woody plants to species diversity and above-ground biomass(AGB),with 17 plots(0.5-1ha)across five sites representing both extremes of rainfall gradient spanning the Miombo ecoregion,in northeast Namibia(500-700mm mean annual precipitation,MAP)and southern Democratic Republic of Congo(DRC)(>1,200mm MAP).Mean AGB per site ranged from 21 to 119Mg·ha^(-1),increasing with rainfall,while the proportional AGB contribution of small trees,saplings,and shrubs decreased.In dry Namibia,small trees,saplings,and shrubs(<5cm DBH)contributed up to 28.2%of total AGB(mean±standard deviation:18.3%±3.4%),whereas in wet DRC,they contributed only up to 2.5%(2.3%±1.4%).Namibian sites,on average,contained a large proportion of woody species diversity exclusively in small trees and shrubs(<5cm DBH),with 55 species representing 59.4%of the total diversity.In contrast,DRC sites had higher overall small woody plant diversity(66 species)but fewer species found exclusively as small individuals(25.2%),with many saplings that grow to larger trees.Understorey composition also differed,with saplings of overstorey trees dominating in DRC,while shrubs dominated in Namibia.Our findings show that woody biomass and diversity in dry woodlands are substantially underestimated when studies focus only on larger trees.This highlights the need to consider all woody vegetation to better understand woody plant diversity and biomass variation.
基金support of the National Biodiversity Future Center (NBFC) to the University of Padova,the Research Centre for Plant ProtectionCertification (CREA),and the National Research Council (CNR),funded under the National Recovery and Resilience Plan (NRRP)+2 种基金Mission 4 Component 2 Investment 1.4-Call for tender No.3138 of 16 December 2021,rectified by Decree n.3175 of 18 December 2021 of Italian Ministry of University and Research funded by the European Union–NextGenerationEUProject code CN_00000033,Concession Decree No.1034 of 17 June 2022adopted by the Italian Ministry of University and Research,CUP:C93C22002810006,CUP:B83D21014060006,CUP:B83C22002930006,Project title“National Biodiversity Future CenterNBFC”support by Beaver Trust,grant number:1185451
文摘The Eurasian beaver(Castor fiber Linnaeus,1758)can be considered a hydrological ecosystem engineer as it shapes environmental characteristics through its building activities and feeding behaviour.Even if several studies have so far reported beaver impact on multi-taxon biodiversity and forest regeneration,there is a lack of research on forest stand structure evolution following beaver direct activity on trees.This represents a pivotal topic for predicting restoration outcomes and reccommending sound silvicultural and management practices to maintain specific forest conditions.Specifically,the study aims at investigating forest stand structure and tree species diversity changes considering river variability,distance from the riverbank and beaver's gnawing activity intensity.The Eurasian beaver is only recently recolonising the three analysed Mediterranean rivers,but stand structure seems to be already significantly impacted by the species.The number of trees was reduced,increasing mean diameter at breast height at stand level,as most of the youngest and/or smaller trees are entirely cut down.Strongest structural variations can be detected in intensively impacted stands and in the forest portions closer to the riverbank.The absence of a significant effect on most of the diversity indices is likely due to the initially homogeneous composition of the tree layer in each stand and to the limited variety of beaver's diet within the sites.Future resprouting of secondary tree shoots,as well as beaver gnawing activity changes in intensity over time and space,can further produce variations in structural parameters and woody species diversity in the medium-and long-term period.Therefore,it will be crucial to further monitor the long-term effects,as structural shifts can produce significant effects on riparian ecosystem functions.
基金supported by the United States-Israel Binational Science Foundation(BSF Grant 2012081).
文摘We explored if and how seasonal fires interact with microhabitat type(i.e.under Pistacia shrub,under Cistus shrub or a canopy gap)to influence the composition of the germinable soil seed bank(GSSB)community in a typical eastern Mediterranean woodland.We conducted a field experiment,involving prescribed spring and autumn burns,and thereafter quantified the seed germination patterns using soil samples collected from both burned and adjacent unburned control plots.Soil temperature was significantly higher during autumn burns,while being more variable during spring burns.Fire caused overall reductions in GSSB density,richness and diversity.The reductions in GSSB richness and diversity were significantly stronger under Pistacia and Cistus shrubs located within plots subjected to autumn burns,and these patterns were mainly evident among annuals.GSSB density of dwarf shrubs was higher in samples collected from burned plots,and this pattern was more pronounced in samples collected under Pistacia and Cistus shrubs.Together with the appearance of unique species,seasonal fires led to significant changes in the composition of the GSSB community.Our results illustrate that seasonal fires interact with spatial heterogeneity to influence the composition of the GSSB community mostly via differential effects on the germination densities of annuals and dwarf shrubs.These findings imply that the increase in the frequency of seasonal fires,which has occurred in the eastern Mediterranean basin during the last few decades,may translate into a shift in eco-evolutionary selection pressures,operating on plants inhabiting this unique ecosystem.
基金R.O.-H.is supported by a Ramon y Cajal Fellowship from MICIU(RYC-2017-22032)projects(PID2019-106004RA-I00).
文摘Aims Given the key functional role of understorey plant communities and the substantial extent of forest cover at the global scale,investigating understorey community responses to elevated CO_(2)(eCO_(2))concentrations,and the role of soil resources in these responses,is important for understanding the ecosystem-level consequences of rising CO_(2)concentrations for forest ecosystems.Here,we evaluated how experimentally manipulating the availabilities of the two most limiting resources in an extremely phosphorus-limited eucalypt woodland in eastern Australia(i.e.water and phosphorus)can modulate the response of the understorey community to eCO_(2)in terms of germination,phenology,cover,community composition and leaf traits.Methods We collected soil containing native soil seed bank to grow experimental understorey plant communities under glasshouse conditions.Important Findings Phosphorus addition increased total plant cover,particularly during the first 4 weeks of growth and under high water conditions,a response driven by the graminoid component of the plant community.However,the treatment differences diminished as the experiment progressed,with all treatments converging at〜80%lant cover after〜11 weeks.In contrast,plant cover was not affected by eCO_(2).Multivariate analyses reflected temporal changes in the composition of plant communities,from pots where bare soil was dominant to high-cover pots dominated by a diverse community.However,both phosphorus addition and the interaction between water availability and CO_(2)affected the temporal trajectory of the plant community during the experiment.eCO_(2)also increased community-level specific leaf area,suggesting that functional adaptation of plant communities to CO_(2)may precede the onset of compositional responses.Given that the response of our seed bank-derived understorey community to CO_(2)developed over time and was mediated by interactions with phosphorus and water availability,our results suggest a limited role of eCO_(2)in shaping plant communities in water-limited systems,particularly where low soil nutrient availability constrains productivity responses.
基金supported by the Fundamental Research Funds for the Central Universities of China and David Eldridge by the Hermon Slade Foundation.
文摘Trees provide multiple ecosystem services such as carbon sequestration,hydrological regulation and habitat for arboreal animals.However,they are often removed to support agricultural enterprises.Despite the importance of tree remnants,we know relatively little about how soils differ across sites of varying condition.Here,we describe a study where we examined the relative effects of trees,compared with unvegetated interspaces,on soil functions in remnant patches at sites in good and poor condition in two eucalypt communities in an irrigation area in eastern Australia.We found that,in general,carbon and nutrient cycling were relatively greater beneath trees,and in surface soils,but there were no clear trends in relation to site condition.The values of most soil attributes(e.g.,soluble and exchangeable cations,nitrogen,phosphorus)were greater beneath trees,indicating strong fertile island effects in both communities.Overall,our study confirms the importance of trees in remnant patches in agricultural landscapes,particularly those in sites of poor condition.It also suggests that soil processes may still be relatively intact,even in sites in poor condition.Our study reinforces the need to protect trees in remnant woodland reserves to maintain critical ecosystem functions related to nutrient retention.These remnants are important for achieving sustainable management of agricultural systems.
基金Supported by Zunyi City Municipal and University Joint Science and Technology R&D Funding Project(HZ2023159)Zunyi Science and Technology Support Program Project(NS2023015)+2 种基金Guizhou Provincial Science and Technology Commissioner Innovation and Entrepreneurship Service Training Demonstration Base(HHG2023001)Guizhou Provincial Department of Education Natural Science Research Project(Qianjiaotongqi[2022]No.067)Natural Science Research Program of Guizhou Provincial Department of Education(Guizhou Education and Technology[2023]043).
文摘Honghuagang District,Zunyi City,Guizhou Province,develops the characteristic industry of crispy peaches,and at the same time develops the forest economy and promotes the model of planting soybeans in peach orchards to promote rural revitalization.However,due to the different pests and diseases occurring in peach trees and soybeans,the control drugs used are also different,and the existing technology for spraying and controlling peach or soybean seedlings is operated separately and cannot be sprayed together at the same time.This study,based on the actual situation of forest land,develops a spraying device for interplantation in forest(peach tree and soybean)from the aspects of technical solutions,working principles and beneficial effects,in order to solve the problem of low spraying efficiency of spraying control of peach tree or soybean seedlings in the existing technology.
基金support by project SUPERB H2020(Systemic solutions for upscaling of urgent ecosystem restoration for forest related biodiversity and ecosystem services)support by project P2013/MAE-2760(Autonomous Community of Madrid)+3 种基金support by project PID2019-107256RB-I00(Spanish Ministry of Science and Innovation)project FAGUS by the Comunidad de Madrid through the call Research Grants for Young Investigators from Universidad Polit ecnica de Madridsupport by projects 9OHUU0-10-3L226X(Autonomous Community of Madrid)RTI2018-094202-BC21 and RTI2018-094202-A-C22(Spanish Ministry of Science and Innovation)。
文摘There is an increasing interest in restoring degraded forests,which occupy half of the forest areas.Among the forms of restoration,passive restoration,which involves the elimination of degrading factors and the free evolution of natural dynamics by applying minimal or no management,is gaining attention.Natural dynamics is difficult to predict due to the influence of multiple interacting factors such as climatic and edaphic conditions,composition and abundance of species,and the successional character of these species.Here,we study the natural dynamics of a mixed forest located in central Spain,which maintained an open forest structure,due to intensive use,until grazing and cutting were banned in the 1960s.The most frequent woody species in this forest are Fagus sylvatica,Quercus petraea,Quercus pyrenaica,Ilex aquifolium,Sorbus aucuparia,Sorbus aria and Prunus avium,with contrasting shade and drought tolerance.These species are common in temperate European deciduous forest and are found here near their southern distribution limit,except for Q.pyrenaica.In order to analyze forest dynamics and composition,three inventories were carried out in 1994,2005 and 2015.Our results show that,despite the Mediterranean influence,the natural dynamics of this forest has been mainly determined by different levels of shade tolerance.After the abandonment of grazing and cutting,Q.pyrenaica expanded rapidly due to its lower shade tolerance,whereas after canopy closure and forest densification,shade-tolerant species gained ground,particularly F.sylvatica,despite its lower drought and late-frost tolerance.If the current dynamics continue,F.sylvatica will overtake the rest of the species,which will be relegated to sites with shallow soils and steep slopes.Simultaneously,all the multi-centennial beech trees,which are undergoing a rapid mortality and decline process,will disappear.
