Botanical gardens represent important places for ex situ conservation.One of these botanical gardens has been abandoned in Côte d’Ivoire for 30 years.This is the former botanical garden of ORSTOM.This study was ...Botanical gardens represent important places for ex situ conservation.One of these botanical gardens has been abandoned in Côte d’Ivoire for 30 years.This is the former botanical garden of ORSTOM.This study was conducted to determine the level of diversity of this former garden in order to assess the opportunity for its rehabilitation.The authors carried out inventories in 18 quadrats of 500 m2 through the vegetation to collect woody species.Dendrometric measurements(height,diameter)were also recorded to assess the structure of the site.A total of 190 species have been identified.They belong to 141 genera and 47 families.This former botanical garden contains important species because of their origin,status or particularity(threatened,endemic,rarity,etc.).A total of 19 threatened species including 2 endangered and west African endemic(Chrysophyllum azaguieanum J.Miège,Placodiscus pseudostipularis)were found at the site.Also,Chrysophyllum azaguieanum is declared extinct from Côte d’Ivoire.Four species are rare in the flora of Côte d’Ivoire:Balanites wilsoniana,Chrysophyllum azaguieanum,Gilletiodendron kisantuense and Loesenera kalantha.The most abundant species is Hopea odorata.Although this introduced species is considered globally vulnerable,it presents a risk of invasion in the forest of Côte d’Ivoire.The diameter and height structures show that all the stages of development are presented indicating a good regeneration on the site.Ultimately,this botanical garden deserves to be rehabilitated and especially urgent management of Hopea odorata is needed to prevent an invasion of this species.展开更多
Stomata control carbon and water vapor exchange between the leaves and the atmosphere,thus infl uencing photosynthesis and transpiration.Combinations of forest patches with different stand ages are common in nature,ho...Stomata control carbon and water vapor exchange between the leaves and the atmosphere,thus infl uencing photosynthesis and transpiration.Combinations of forest patches with different stand ages are common in nature,however,information of which stomatal traits vary among these stands and how,remains limited.Here,seven different aged forest stands(6,14,25,36,45,55,and 100 years)were selected in typical temperate,mixed broadleaf-conifer forests of northeast China.Stomatal density,size and relative area of 624 species,including the same species in stands of different ages were selected.Stomatal density,size and relative area were distributed log-normally,differing across all species and plant functional groups.Stomatal density ranged from 4.2 to 1276.7 stomata mm^(–2),stomatal size ranged from 66.6 to 8315.7μm^(2),and stomatal relative area 0.1–93.3%.There was a significant negative relationship between density and size at the species and functional group levels,while the relative stomatal area was positively correlated with density and size.Stomatal traits of dominant species were relatively stable across different stand ages but were significantly different for herbs.The results suggest that stomatal traits remain relatively stable for dominant species in natural forests and therefore,spatial variation in stomatal traits across forest patches does not need to be incorporated in future ecological models.展开更多
As forests in neotropical regions,particularly in developing countries,are devastated,interventions to restore biodiversity and its ecological functions are needed.Rural producers have thus been encouraged to grow tre...As forests in neotropical regions,particularly in developing countries,are devastated,interventions to restore biodiversity and its ecological functions are needed.Rural producers have thus been encouraged to grow trees for wood production as an economic activity.The objective of this study was to quantify the increment of wood density of four forest species from different successional classes of a mixed system of restoration in a neotropical forest in Brazil.Tree discs were sampled at breast height and analyzed radially by X-ray densitometry to obtain apparent density and basic density.Three trees each of a species from the pioneer,early and late secondary successional stages and of the dominant species in the climax community.The radial profiles indicated increasing density from the pith to bark of trunks,except for some variations due to wood defects and growth.Average density was 0.576 g cm^(-3),0.655 g cm^(-3),0.706 g cm^(-3)and 0.775 g cm^(-3),respectively,for Peltophorum dubium,Schinus terebinthifolius,Cariniana estrellensis and Hymenaea courbaril.Radial profiles indicated higher amplitudes in the apparent densities for slow-growing species.X-ray densitometry generated parameters such as minimum,average and maximum densities,and radial density variations.These parameters are important for understanding the ecological functional role of successional classes of the Atlantic Forest from the Neotropical region.展开更多
Background:Conceptual models of forest dynamics are powerful cognitive tools,which are indispensable for communicating ecological ideas and knowledge,and in developing strategic approaches and setting targets for fore...Background:Conceptual models of forest dynamics are powerful cognitive tools,which are indispensable for communicating ecological ideas and knowledge,and in developing strategic approaches and setting targets for forest conservation,restoration and sustainable management.Forest development through time is conventionally described as a directional,or "linear",and predictable sequence of stages from "bare ground" to old forest representing the "climax-state".However,this simple view is incompatible with the current knowledge and understanding of intrinsic variability of forest dynamics.Hypothesis:Overly simple conceptual models of forest dynamics easily become transformed into biased mental models of how forests naturally develop and what kind of structures they display.To be able to communicate the essential features and diversity of forest dynamics,comprehensive conceptual models are needed.For this end,Kuuluvainen(2009) suggested a relatively simple conceptual model of forest dynamics,which separates three major modes of forest dynamics,and incorporates state changes and transitions between the forest dynamics modes depending on changes in disturbance regime.Conclusions:Conceptual models of forest dynamics should be comprehensive enough to incorporate both longterm directional change and short-term cyclic forest dynamics,as well as transitions from one dynamics mode to another depending on changes in the driving disturbance regime type.Models that capture such essential features of forest dynamics are indispensable for educational purposes,in setting reference conditions and in developing methods in forest conservation,restoration and ecosystem management.展开更多
Natural secondary forest has a strong capacity to regrow naturally and recover biodiversity rapidly on abandoned lands.However,at the neighborhood scale,which can truly reflect the facilitative or competitive interact...Natural secondary forest has a strong capacity to regrow naturally and recover biodiversity rapidly on abandoned lands.However,at the neighborhood scale,which can truly reflect the facilitative or competitive interactions among individual plants,the local diversity spatial structure in secondary forest and the feedback effects of neighborhood diversity on natural regeneration remain unclear,and this may be the key to properly understand the mechanisms of natural secondary forest species diversity recovery.To this end,this study established a dynamic plot in a rehabilitated secondary forest after disturbance and conducted a comprehensive survey of 68,336 individual plants with repeated measurements at 5-year interval to assess the characteristics of neighborhood diversity structure across life history stages and link the neighborhood species richness(NSR)effect translated by species interactions at species diversity structure with individual trees recruitment/mortality in secondary forest regeneration.The results showed that,compared with tropical and temperate natural forests,a higher proportion of diversity accumulators and a lower proportion of repellers in subtropical secondary forests resulted in neighborhood diversity structures characterized by heterospecific or high-diversity patches,which are beneficial to the maintenance or restoration of biodiversity.As an important supplement to the research on the relationship between diversity and productivity,our findings show a positive diversity-survival relationship in subtropical secondary forests.Importantly,we observed that the neighborhood diversity structure exhibited a trend of accumulator-dominated to neutral-dominant changes with life stage from sapling to adult,which,in turn,determined the direction and strength of NSR effects on recruitment/mortality.Specifically,diverse local neighborhoods at a later successional stage characterized with‘neutral’species-species interactions can act as a‘welfare net’by offering favorable microhabitats for the most vulnerable recruitments or saplings,i.e.,the NSR effects that promoted individual recruitment/survival in our study.These results not only enrich our understanding of the biodiversity-productivity-survival relationship but also highlight the importance of retaining latesuccessional species of native trees in intensive forest production or in situ conservation policies.展开更多
Increased urbanization coupled with increased reliance of urban communities on rural areas for ecosystem service provision is a challenge faced by many nations. The ability of urban households to directly support rest...Increased urbanization coupled with increased reliance of urban communities on rural areas for ecosystem service provision is a challenge faced by many nations. The ability of urban households to directly support restoration efforts in surrounding rural regions represents an underappreciated funding stream for ecological restoration. This study explored the willingness of urban households to support forest restoration in Vietnam. We surveyed 211 households (HHs) in the capital city Hanoi, Vietnam. A Maximum Likelihood Estimator (MLE) model allowed us to obtain the parameters of our model and quantify mean Willingness-to-Pay (WTP) for a program of forest restoration in addition to identifying factors influencing the decision of WTP. Generally, over forty percent of the households surveyed are willing to pay for forest restoration and the mean value of WTP is 37,830 VND ($1.73) per household per month. WTP depends on endogenous and exogenous factors including level of education, income, female-to-male ratio in the household, attitude toward payment for monthly electricity consumption, and awareness of payment for environmental service. Our results suggest that urban household’s demand for forest restoration is real, and represents an untapped source of restoration funding. Policy-makers should take actions to apply charges on water bills to turn this potential into reality for restoration projects in Vietnam if the benefits from restoration outweigh the costs based on our findings.展开更多
Currently there is an urgent and special attention in actions to restore tropical forests.In this study,we evaluated the effect of different restoration methods on aboveground biomass(AGB)stock,tree community diversit...Currently there is an urgent and special attention in actions to restore tropical forests.In this study,we evaluated the effect of different restoration methods on aboveground biomass(AGB)stock,tree community diversity and structure,in areas affected by the Fundão tailings dam collapse in Mariana,Minas Gerais state,Brazil.We measured and compiled data of the AGB,community diversity and structure attributes in 36 plots distributed in six restoration treatments and six replicas:planting of native tree seedlings with fertilization and pH correction(PSf)and without fertilization and pH correction(PS);seeding of native trees with fertilization and pH correction(SDf)and without fertilization and pH correction(SD);natural regeneration with fertilization and pH correction(NRf)and without fertilization and pH correction(NR).No significant differences in substrate properties and AGB between treatments.Although biomass storage between treatments was not statistically different,there is a clear pattern showing higher values active restoration method.The Pielou index ranged from 0.520(SDf)to 0.943(NR),except for SDf all the others treatments had values higher than 0.76.This result suggests floristic heterogeneity,without ecological dominance in the plant community.Overall,active restoration had important implications for the forest restoration where natural regeneration is limited.展开更多
Deforestation and forest degradation are having profound negative impacts on social-ecological systems in the emerging economies across the tropics.Consequently,interest in restoring and rehabilitating degraded forest...Deforestation and forest degradation are having profound negative impacts on social-ecological systems in the emerging economies across the tropics.Consequently,interest in restoring and rehabilitating degraded forests has been growing.This paper explores current issues related to addressing forest degradation in the Lancang-Mekong Region(LMR)of Southeast Asia through a review of the use of criteria and indicators for forest degradation and rehabilitation.Forest degradation must be understood in the context of its underlying drivers,which are numerous and complex.Understanding these underlying drivers of degradation requires diagnosing the entwined political,social,economic,and environmental systems that aff ect forests.Landscapes are the relevant scales to diagnose and intervene for improved forests.Interventions to restore or rehabilitate forests should be process-driven,focused on the underlying social,ecological and political processes that degrade landscapes.Interventions should also include negotiation among all actors infl uencing and competing for natural resource claims in forest landscapes.Criteria and indicators for forest landscape restoration should therefore help to improve the governance of forest landscapes.Criteria and indicators provide measures of the biophysical outcomes of degradation,in addition to processes,but these should be adapted to changing contexts and emerging challenges,and should rectify any pre-existing fl awed change-logic.Restoration activities should synthesize,integrate,and build upon the rich history of pre-existing restoration guidelines,but should be adaptable in order to be applied eff ectively in the contexts of local landscapes.This project is facilitating a dialogue around the use of criteria and indicators to help solve the degradation challenge in the LMR.We will trial the use of the criteria and indicators generated through this research in the LMR to learn what works and what doesn’t.This will provide an opportunity to build consensus around the ways in which restoration investments made by governments,civil society,and the private sector can infl uence sustainability.展开更多
Although the scientific knowledge about some associations between physical parameters of the soil is consolidated,studies focused on investigating the dynamics of forest restoration processes and the structure of soil...Although the scientific knowledge about some associations between physical parameters of the soil is consolidated,studies focused on investigating the dynamics of forest restoration processes and the structure of soils remain incipient.The study area is located in Cerrado and is called as Private Natural Heritage Reserve(RPPN)Águas Perenes Forest(perennial water forest)and was selected as a“High Conservation Value Forest”,provides scope to investigate the soil physical properties recovery on passive restoration sites,with different ages but with the same land use history.So,the aim was to investigate the soil density,moisture,penetration resistance and infiltration rate with long-term from old(FA,46 year-old),medium(FB,11 year-old)and young(FC,8 year-old)passive restoration sites.It was observed differences in soil density,as well as in soil moisture,resistance to penetration and infiltration rate.Mean densities recorded for FA,FB and FC were 1.38,1.48 and 1.53 g cm^(-3),respectively.FA recorded higher mean soil moisture(14.9%)than FB(11.5%)and FC(10.0%),whereas mean soil resistance to penetration was increased from FA(0.87 MPa)to FB(0.91 MPa)and FC(1.10 MPa).The average infiltration rate was almost similar in FA and FB(FA=76.43 mm h^(-1);FB=77.48 mm h^(-1))and approximately 39%higher than FC(55.79 mm h^(-1)).Thus,although soil density and moisture were different in each passive restoration site,11 year-old passive restoration site showed similar resistance to penetration and infiltration rate to the old(46 years)passive restoration site.These features allowed seeing improvements in hydrological maintenance in the soil and revealed that passive restoration in Cerrado is able to improve the physical features on a soil presenting similar texture,climate and management history.展开更多
The scale of forest and landscape restoration is expected to increase during the UN Decade on Ecosystem Restoration and its contribution to the provision of critical ecosystem services to society.Several models of for...The scale of forest and landscape restoration is expected to increase during the UN Decade on Ecosystem Restoration and its contribution to the provision of critical ecosystem services to society.Several models of forest restoration may improve ecosystem services,including soil organic carbon(SOC)storage.A review was carried out to access:(1)the variability of SOC storage between worldwide forest restoration models and,(2)the effects of climate,soil class,soil texture,and vegetation type on SOC storage.We reviewed 119 primary studies with information on SOC and soil texture for different forest restoration models.The restoration models were grouped into four categories:natural regeneration,monocultures,agroforestry,and mixed forest.SOC data was extracted from these four restoration models,other land uses(cropland,bare land,grassland,and natural forest),climate regimes,and soil properties.The SOC storage in the forest restoration models and other land uses at a global scale ranged between 0.1 to 514 Mg ha^(-1).The overall mean value for SOC storage was higher for natural regeneration(112 Mg ha^(-1)),followed by agroforestry(74 Mg ha^(-1)),mixed forest(73 Mg ha^(-1)),and monocultures(68 Mg ha^(-1)).However,the average SOC storage was similar among the four restoration models in the moist warm climate zone.The SOC storage mean value in the moist cool zone was 23%higher than the dry cool zone(81 and 62 Mg ha^(-1),respectively),and 50%higher for the moist warm zone when compared to the dry warm climatic zone(74 and 38 Mg ha^(-1),respectively).The SOC storage of the restoration models was positively related to soil depth(0.59;p<0.01),clay content(0.29;p<0.01),and stand age(0.17;p<0.01).Globally,the mean values of SOC storage were 26,66,and 139 Mg ha^(-1) at zero-10,zero-30,and zero-100 cm depths,respectively.In addition,sandy soils showed smaller mean values of SOC storage than medium to clay soils,especially in deeper soil layers.Furthermore,SOC storage was positively related between restoration models and other land uses(0.93;p<0.01),suggesting a prominent effect of climate and soil properties on SOC.Forest restoration models showed larger SOC storage when compared to croplands and bare land,but in general it was smaller or similar when compared to pasture and natural forest.展开更多
Background:Forest restoration has been considered an effective method to increase soil organic carbon(SOC),whereas it remains unclear whether long-term forest restoration will continuously increase SOC.Such large unce...Background:Forest restoration has been considered an effective method to increase soil organic carbon(SOC),whereas it remains unclear whether long-term forest restoration will continuously increase SOC.Such large uncertainties may be mainly due to the limited knowledge on how soil microorganisms will contribute to SOC accumulation over time.Methods:We simultaneously documented SOC,total phospholipid fatty acids(PLFAs),and amino sugars(AS)content across a forest restoration gradient with average stand ages of 14,49,70,and>90 years in southern China.Results:The SOC and AS continuously increased with stand age.The ratio of fungal PLFAs to bacterial PLFAs showed no change with stand age,while the ratio of fungal AS to bacterial AS significantly increased.The total microbial residue-carbon(AS-C)accounted for 0.95-1.66% in SOC across all forest restoration stages,with significantly higher in fungal residue-C(0.68-1.19%)than bacterial residue-C(0.05-0.11%).Furthermore,the contribution of total AS-C to SOC was positively correlated with clay content at 0-10 cm soil layer but negatively related to clay content at 10-20 cm soil layer.Conclusions:These findings highlight the significant contribution of AS-C to SOC accumulation along forest restoration stages,with divergent contributions from fungal residues and bacterial residues.Soil clay content with stand age significantly affects the divergent contributions of AS-C to SOC at two different soil layers.展开更多
Background:Robinia pseudoacacia is a widely planted pioneer tree species in reforestations on barren mountains in northern China.Because of its nitrogen-fixing ability,it can play a positive role in soil and forest re...Background:Robinia pseudoacacia is a widely planted pioneer tree species in reforestations on barren mountains in northern China.Because of its nitrogen-fixing ability,it can play a positive role in soil and forest restoration.After clearcutting of planted stands,R.pseudoacacia stands become coppice plantations.The impacts of shifting from seedling to coppice stands on soil bacterial community and soil properties have not been wel described.This study aims to quantify how soil properties and bacterial community composition vary between planted seedling versus coppice stands.Methods:Nine 20 m×20 m plots were randomly selected in seedling and coppice stands.The bulk soil and rhizosphere soil were sampled in summer 2017.Bulk soil was sampled at 10 cm from the soil surface using a soil auger.Rhizosphere soil samples were col ected using a brush.The soil samples were transported to the laboratory for chemical analysis,and bacterial community composition and diversity was obtained through DNA extraction,16 S r RNA gene amplification and high-throughput sequencing.Results:The results showed that,compared to seedling plantations,soil quality decreased significantly in coppice stands,but without affecting soil exchangeable Mg^(2+) and K^(+).Total carbon(C)and nitrogen(N)were lower in the rhizosphere than in bulk soil,whereas nutrient availability showed an opposite trend.The conversion from seedling to coppice plantations was also related to significant differences in soil bacterial community structure and to the reduction of soil bacterialα-diversity.Principal component analysis(PCA)showed that bacterial community composition was similar in both bulk and rhizosphere soils in second-generation coppice plantations.Special y,the conversion from seedling to coppice stands increased the relative abundance of Proteobacteria and Rhizobium,but reduced that of Actinobacteria,which may result in a decline of soil nutrient availability.Mantel tests revealed that C,N,soil organic matter(SOM),nitrate nitrogen(NO^(-)+(3)-N)and available phosphorus positively correlated with bacterial community composition,while a variation partition analysis(VPA)showed that NO^(-)+(3)-N explained a relatively greater proportion of bacterial distribution(15.12%),compared with C and SOM.Surprisingly,N showed no relationship with bacterial community composition,which may be related to nitrogen transportation.Conclusions:The conversion from seedling to coppice stands reduced soil quality and led to spatial-temporal homogenization of the soil bacterial community structure in both the rhizosphere and bulk soils.Such imbalance in microbial structure can accelerate the decline of R.pseudoacacia.This may affect the role of R.pseudoacacia coppice stands in soil and forest restoration of barren lands in mountain areas.展开更多
We investigated the arbuscular mycorrhizal fungi(AMF)status of ten nurseries suitable for restoration of dry evergreen Afromontane forests in Ethiopia.We quantified AMF root colonization(RC)and spore abundance(SA)in s...We investigated the arbuscular mycorrhizal fungi(AMF)status of ten nurseries suitable for restoration of dry evergreen Afromontane forests in Ethiopia.We quantified AMF root colonization(RC)and spore abundance(SA)in seedlings of nine native tree species namely Acacia abyssinica Hochst.ex Benth.,Cordia africana Lam.,Dovyalis abyssinica(A.Rich.)Warb.,H agenia abyssinica J.F.Gmel.,Juniperus procera Hochst.ex Endl.,Millettia ferruginea(Hochst.)Baker,Olea europaea L.subsp.c uspidata(Wall.ex G.Don)Cif.,Podocarpus falcatus(Thunb.)R.Br.ex Mirb.and Prunus africana(Hook.f.)Kalkman.We used the ink and vinegar method to stain AMF in roots.RC levels ranged from 8.00 to 99.67%and were generally higher than the RC levels reported from other similar nurseries in Ethiopia.SA levels ranged from 1 to 25 spores g~(-1)and werecomparable with some reports from the field in Ethiopia but they were lower than levels reported by another similar study.RC was more affected by host species than nursery location,while the reverse was true for SA.The results also showed that nursery management could improve AMF status among seedlings.When all nursery tree species were considered,RC and SA levels were unrelated.No strong correlation existed between the nursery management variables considered and RC or SA.However,considering C.africana,J.procera and P.falcatus separately,RC-age(r_(s)=0.829,P=0.042)correlation for O.europaea and RC-pot diameter(r_(s)=0.820,P=0.046),RC-pot volume(r_(s)=0.928,P=0.008)and SA-age(r_(s)=0.943,P=0.005)correlations for C.africana,were significant,strong and positive.Generally,most of the tree species and particularly,early-mid successional tree species had sufficient AMF inoculum.Hence,only the mid-late successional tree species;J.procera,P.falcatus,and P.africana may require AMF inoculation,preferably,during filed planting.Based on our results,age and pot volume were identified to be important variables potentially affecting RC and SA.To better understand the effects of these and other nursery management variables,additional study is required.We demonstrated for the first time that black Hero ink is suitable for staining root AMF and can be used in future AMF research.展开更多
This study aims to analyze temporal changes in land use and land cover change (LUCC) as well as identify areas for natural regeneration and potential areas for forest restoration in the Huasteca region for the period ...This study aims to analyze temporal changes in land use and land cover change (LUCC) as well as identify areas for natural regeneration and potential areas for forest restoration in the Huasteca region for the period from 1976 to 2007. Changes were quantified in numbers and, additionally, cartography was used to identify and map the main affected areas. Different models based on Geographic Information Systems (GIS) demonstrated that LUCC have occurred on an area of 11718.82 km2, representing 17.84% of the region’s surface. Agriculture and the growth of pasture could be identified as the main human-induced activities that have led to landscape modification. In addition, forest cover is affected by a deforestation rate which is higher than the national average. Further important changes include a change from natural land cover to non-original land cover, affecting an area of 4911.88 km2 in the period from 1976-1993, and an area of 1892.5 km2 in the period from 1993-2002. Smaller changes could be observed for the period from 1993-2002 with an affected area of 1029.78 km2. At the same time, a natural regeneration from nonoriginal to original land cover took place from 1976-1993 on an area of 1318.68 km2, and also on an area of 974.18 km2 between 1993 an 2002. The surface that underwent a natural regeneration of forest cover made up 1932.07 km2. At the same time, an area of 5739.29 km2 for potential forest restoration was identified. Drawing on GIS methods and techniques, the development of thematic maps for land use, land use and land cover changes for the years of analysis (1976-1993-2002-2007) proved to be very adequate for the evaluation and analysis of the land cover and land use change, in particular with regard to the decrease of natural vegetation cover.展开更多
Aims For assisting faster restoration of damaged or severely disturbed coastal ecosystems,selected mangrove species have been planted on previously mangrove-inhabited sites of the tropical and subtropical coasts of so...Aims For assisting faster restoration of damaged or severely disturbed coastal ecosystems,selected mangrove species have been planted on previously mangrove-inhabited sites of the tropical and subtropical coasts of southern China.The objective of this study was to understand the stand dynamics of the planted mangroves and their functional traits in comparison with natural mangrove forests under similar site conditions.Methods Species composition,stand density,tree size distribution,and aboveground production were investigated along three transects in a 50-year-old planted mangrove stand and three transects in an adjacent natural mangrove stand in Shenzhen Bay,South China.Measurements were made on tree distribution by species,stand structure,and aboveground biomass(AGB)distribution.Analyses were performed on the spatial patterns of tree size distribution and species association.Important Findings We found that the planted and natural mangrove stands did not differ in stand density,average diameter at breast height(DBH),species composition,and AGB.Spatial distribution of AGB and frequency at species level were also similar between the planted and natural stands.However,the traits in stand structure were more variable in the planted stand than in the natural stand,indicating higher spatiotemporal heterogeneity in the development and succession of planted mangroves.Geostatistical analyses show that both DBH and AGB were spatially auto-correlated within a specific range in the direction perpendicular to coastline.More than 60%of the variance in these attributes was due to spatial autocorrelation.The Ripley’s K-function analysis shows that the two dominant species,Kandelia obovata and Avicennia marina,clumped in broader scales in the natural stand than in the planted stand and displayed significant interspecific competition across the whole transect.It is suggested that interspecific competition interacts with spatial autocorrelation as the underlying mechanism shaping the mangrove structure.This study demonstrates that at age 50,mangrove plantations can perform similarly in stand structure,spatial arrangement of selected stand characteristics and species associations to the natural mangrove forests.展开更多
Background:Granivore-mediated seed dispersal is susceptible to changes in seed availability and silvicultural management,which alters synzoochorous interactions in the antagonism-mutualism continuum and affects the se...Background:Granivore-mediated seed dispersal is susceptible to changes in seed availability and silvicultural management,which alters synzoochorous interactions in the antagonism-mutualism continuum and affects the seed dispersal effectiveness(SDE),and eventually,the plant recruitment.We conducted a whole-year study of seed addi-tion to quantify the granivores-Korean pine(Pinus koraiensis)synzoochorous interactions and the SDE in the same sec-ondary forests with two treatments.Both treatments had seed source limitations:one was caused by the disappear-ance of Korean pine due to the historical disturbance,the other by pinecone harvesting in Korean pine plantations adjacent to the secondary forests.Thinning with different intensities(control,25%,and 50%)were also performed to further explore the synzoochorous interactions and SDE in response to silvicultural management in the second type of forests.Results:Source limitation increased the proportion of pre-and post-dispersal seed predation,and made the granivores-Korean pine interaction shift more towards antagonism,with the estimated SDE of 2.31 and 3.60,respec-tively,for the secondary forests without and with Korean pine.Thinning with different intensities did not alleviate the reactions towards antagonism but altered SDE;granivores occurrence decreased,but the proportion of pre-and post-dispersal seed predation increased,resulting in a fivefold decreased seedling recruitment in 25%thinning(the lowest SDE of 0.26).Conclusion:The source limitation coupling thinning biased the synzoochorous interactions more towards antago-nism and significantly lowered granivore-mediated SDE,which limited the successful recruitment of Korean pine in secondary forests.Forest managers should control pinecone harvesting,protect the synzoochorous interaction,and take into account masting event for Korean pine regeneration in the future.展开更多
文摘Botanical gardens represent important places for ex situ conservation.One of these botanical gardens has been abandoned in Côte d’Ivoire for 30 years.This is the former botanical garden of ORSTOM.This study was conducted to determine the level of diversity of this former garden in order to assess the opportunity for its rehabilitation.The authors carried out inventories in 18 quadrats of 500 m2 through the vegetation to collect woody species.Dendrometric measurements(height,diameter)were also recorded to assess the structure of the site.A total of 190 species have been identified.They belong to 141 genera and 47 families.This former botanical garden contains important species because of their origin,status or particularity(threatened,endemic,rarity,etc.).A total of 19 threatened species including 2 endangered and west African endemic(Chrysophyllum azaguieanum J.Miège,Placodiscus pseudostipularis)were found at the site.Also,Chrysophyllum azaguieanum is declared extinct from Côte d’Ivoire.Four species are rare in the flora of Côte d’Ivoire:Balanites wilsoniana,Chrysophyllum azaguieanum,Gilletiodendron kisantuense and Loesenera kalantha.The most abundant species is Hopea odorata.Although this introduced species is considered globally vulnerable,it presents a risk of invasion in the forest of Côte d’Ivoire.The diameter and height structures show that all the stages of development are presented indicating a good regeneration on the site.Ultimately,this botanical garden deserves to be rehabilitated and especially urgent management of Hopea odorata is needed to prevent an invasion of this species.
基金supported by the National Natural Science Foundation of China(31,872,683,31,800,368,31,872,690)the National Key Research Project of China(2017YFC0504004,2016YFC0500202)the program of Youth Innovation Research Team Project(LENOM2016Q0005)。
文摘Stomata control carbon and water vapor exchange between the leaves and the atmosphere,thus infl uencing photosynthesis and transpiration.Combinations of forest patches with different stand ages are common in nature,however,information of which stomatal traits vary among these stands and how,remains limited.Here,seven different aged forest stands(6,14,25,36,45,55,and 100 years)were selected in typical temperate,mixed broadleaf-conifer forests of northeast China.Stomatal density,size and relative area of 624 species,including the same species in stands of different ages were selected.Stomatal density,size and relative area were distributed log-normally,differing across all species and plant functional groups.Stomatal density ranged from 4.2 to 1276.7 stomata mm^(–2),stomatal size ranged from 66.6 to 8315.7μm^(2),and stomatal relative area 0.1–93.3%.There was a significant negative relationship between density and size at the species and functional group levels,while the relative stomatal area was positively correlated with density and size.Stomatal traits of dominant species were relatively stable across different stand ages but were significantly different for herbs.The results suggest that stomatal traits remain relatively stable for dominant species in natural forests and therefore,spatial variation in stomatal traits across forest patches does not need to be incorporated in future ecological models.
基金This study is funded by the Coordination for the Improvement of Higher Education Personnel(CAPES).
文摘As forests in neotropical regions,particularly in developing countries,are devastated,interventions to restore biodiversity and its ecological functions are needed.Rural producers have thus been encouraged to grow trees for wood production as an economic activity.The objective of this study was to quantify the increment of wood density of four forest species from different successional classes of a mixed system of restoration in a neotropical forest in Brazil.Tree discs were sampled at breast height and analyzed radially by X-ray densitometry to obtain apparent density and basic density.Three trees each of a species from the pioneer,early and late secondary successional stages and of the dominant species in the climax community.The radial profiles indicated increasing density from the pith to bark of trunks,except for some variations due to wood defects and growth.Average density was 0.576 g cm^(-3),0.655 g cm^(-3),0.706 g cm^(-3)and 0.775 g cm^(-3),respectively,for Peltophorum dubium,Schinus terebinthifolius,Cariniana estrellensis and Hymenaea courbaril.Radial profiles indicated higher amplitudes in the apparent densities for slow-growing species.X-ray densitometry generated parameters such as minimum,average and maximum densities,and radial density variations.These parameters are important for understanding the ecological functional role of successional classes of the Atlantic Forest from the Neotropical region.
文摘Background:Conceptual models of forest dynamics are powerful cognitive tools,which are indispensable for communicating ecological ideas and knowledge,and in developing strategic approaches and setting targets for forest conservation,restoration and sustainable management.Forest development through time is conventionally described as a directional,or "linear",and predictable sequence of stages from "bare ground" to old forest representing the "climax-state".However,this simple view is incompatible with the current knowledge and understanding of intrinsic variability of forest dynamics.Hypothesis:Overly simple conceptual models of forest dynamics easily become transformed into biased mental models of how forests naturally develop and what kind of structures they display.To be able to communicate the essential features and diversity of forest dynamics,comprehensive conceptual models are needed.For this end,Kuuluvainen(2009) suggested a relatively simple conceptual model of forest dynamics,which separates three major modes of forest dynamics,and incorporates state changes and transitions between the forest dynamics modes depending on changes in disturbance regime.Conclusions:Conceptual models of forest dynamics should be comprehensive enough to incorporate both longterm directional change and short-term cyclic forest dynamics,as well as transitions from one dynamics mode to another depending on changes in the driving disturbance regime type.Models that capture such essential features of forest dynamics are indispensable for educational purposes,in setting reference conditions and in developing methods in forest conservation,restoration and ecosystem management.
基金supported by the Innovative Team Project of Nanjing Institute of Environmental Sciences,MEECentral Public Welfare Scientific Institution Basal Research Fund,Ministry of Finance and Ministry of Ecology and Environment of China(Nos.GYZX210302,GYZX200203):Biodiversity Survey,Observation and Assessment Program of Ministry of Ecology and Environment of China+2 种基金The National Environmental Protection Public Welfare Industry Targeted Research Fund:Research and demonstration of key technologies for dynamic supervision of nature reserves(No.201509042)The Special Foundation for National Science and Technology Basic Resources Investigation of China(No.2019FY202300)The Jiangsu Postdoctoral Research Funding Program(No.2021K038A)。
文摘Natural secondary forest has a strong capacity to regrow naturally and recover biodiversity rapidly on abandoned lands.However,at the neighborhood scale,which can truly reflect the facilitative or competitive interactions among individual plants,the local diversity spatial structure in secondary forest and the feedback effects of neighborhood diversity on natural regeneration remain unclear,and this may be the key to properly understand the mechanisms of natural secondary forest species diversity recovery.To this end,this study established a dynamic plot in a rehabilitated secondary forest after disturbance and conducted a comprehensive survey of 68,336 individual plants with repeated measurements at 5-year interval to assess the characteristics of neighborhood diversity structure across life history stages and link the neighborhood species richness(NSR)effect translated by species interactions at species diversity structure with individual trees recruitment/mortality in secondary forest regeneration.The results showed that,compared with tropical and temperate natural forests,a higher proportion of diversity accumulators and a lower proportion of repellers in subtropical secondary forests resulted in neighborhood diversity structures characterized by heterospecific or high-diversity patches,which are beneficial to the maintenance or restoration of biodiversity.As an important supplement to the research on the relationship between diversity and productivity,our findings show a positive diversity-survival relationship in subtropical secondary forests.Importantly,we observed that the neighborhood diversity structure exhibited a trend of accumulator-dominated to neutral-dominant changes with life stage from sapling to adult,which,in turn,determined the direction and strength of NSR effects on recruitment/mortality.Specifically,diverse local neighborhoods at a later successional stage characterized with‘neutral’species-species interactions can act as a‘welfare net’by offering favorable microhabitats for the most vulnerable recruitments or saplings,i.e.,the NSR effects that promoted individual recruitment/survival in our study.These results not only enrich our understanding of the biodiversity-productivity-survival relationship but also highlight the importance of retaining latesuccessional species of native trees in intensive forest production or in situ conservation policies.
文摘Increased urbanization coupled with increased reliance of urban communities on rural areas for ecosystem service provision is a challenge faced by many nations. The ability of urban households to directly support restoration efforts in surrounding rural regions represents an underappreciated funding stream for ecological restoration. This study explored the willingness of urban households to support forest restoration in Vietnam. We surveyed 211 households (HHs) in the capital city Hanoi, Vietnam. A Maximum Likelihood Estimator (MLE) model allowed us to obtain the parameters of our model and quantify mean Willingness-to-Pay (WTP) for a program of forest restoration in addition to identifying factors influencing the decision of WTP. Generally, over forty percent of the households surveyed are willing to pay for forest restoration and the mean value of WTP is 37,830 VND ($1.73) per household per month. WTP depends on endogenous and exogenous factors including level of education, income, female-to-male ratio in the household, attitude toward payment for monthly electricity consumption, and awareness of payment for environmental service. Our results suggest that urban household’s demand for forest restoration is real, and represents an untapped source of restoration funding. Policy-makers should take actions to apply charges on water bills to turn this potential into reality for restoration projects in Vietnam if the benefits from restoration outweigh the costs based on our findings.
基金To the National Council of Scientific and Technological Development of Brazil(CNPq),provided for research fellowships for S.V.Martins and to the Fundação Renova for provided infrastructure and financial support for the project.
文摘Currently there is an urgent and special attention in actions to restore tropical forests.In this study,we evaluated the effect of different restoration methods on aboveground biomass(AGB)stock,tree community diversity and structure,in areas affected by the Fundão tailings dam collapse in Mariana,Minas Gerais state,Brazil.We measured and compiled data of the AGB,community diversity and structure attributes in 36 plots distributed in six restoration treatments and six replicas:planting of native tree seedlings with fertilization and pH correction(PSf)and without fertilization and pH correction(PS);seeding of native trees with fertilization and pH correction(SDf)and without fertilization and pH correction(SD);natural regeneration with fertilization and pH correction(NRf)and without fertilization and pH correction(NR).No significant differences in substrate properties and AGB between treatments.Although biomass storage between treatments was not statistically different,there is a clear pattern showing higher values active restoration method.The Pielou index ranged from 0.520(SDf)to 0.943(NR),except for SDf all the others treatments had values higher than 0.76.This result suggests floristic heterogeneity,without ecological dominance in the plant community.Overall,active restoration had important implications for the forest restoration where natural regeneration is limited.
文摘Deforestation and forest degradation are having profound negative impacts on social-ecological systems in the emerging economies across the tropics.Consequently,interest in restoring and rehabilitating degraded forests has been growing.This paper explores current issues related to addressing forest degradation in the Lancang-Mekong Region(LMR)of Southeast Asia through a review of the use of criteria and indicators for forest degradation and rehabilitation.Forest degradation must be understood in the context of its underlying drivers,which are numerous and complex.Understanding these underlying drivers of degradation requires diagnosing the entwined political,social,economic,and environmental systems that aff ect forests.Landscapes are the relevant scales to diagnose and intervene for improved forests.Interventions to restore or rehabilitate forests should be process-driven,focused on the underlying social,ecological and political processes that degrade landscapes.Interventions should also include negotiation among all actors infl uencing and competing for natural resource claims in forest landscapes.Criteria and indicators for forest landscape restoration should therefore help to improve the governance of forest landscapes.Criteria and indicators provide measures of the biophysical outcomes of degradation,in addition to processes,but these should be adapted to changing contexts and emerging challenges,and should rectify any pre-existing fl awed change-logic.Restoration activities should synthesize,integrate,and build upon the rich history of pre-existing restoration guidelines,but should be adaptable in order to be applied eff ectively in the contexts of local landscapes.This project is facilitating a dialogue around the use of criteria and indicators to help solve the degradation challenge in the LMR.We will trial the use of the criteria and indicators generated through this research in the LMR to learn what works and what doesn’t.This will provide an opportunity to build consensus around the ways in which restoration investments made by governments,civil society,and the private sector can infl uence sustainability.
基金We appreciate the cooperation of the International Paper from Brazil LTDA(Process 23112.000670/2015-59)Federal University of Sao Carlos and the Brazilian National Council for Scientific and Technological Development(CNPq).
文摘Although the scientific knowledge about some associations between physical parameters of the soil is consolidated,studies focused on investigating the dynamics of forest restoration processes and the structure of soils remain incipient.The study area is located in Cerrado and is called as Private Natural Heritage Reserve(RPPN)Águas Perenes Forest(perennial water forest)and was selected as a“High Conservation Value Forest”,provides scope to investigate the soil physical properties recovery on passive restoration sites,with different ages but with the same land use history.So,the aim was to investigate the soil density,moisture,penetration resistance and infiltration rate with long-term from old(FA,46 year-old),medium(FB,11 year-old)and young(FC,8 year-old)passive restoration sites.It was observed differences in soil density,as well as in soil moisture,resistance to penetration and infiltration rate.Mean densities recorded for FA,FB and FC were 1.38,1.48 and 1.53 g cm^(-3),respectively.FA recorded higher mean soil moisture(14.9%)than FB(11.5%)and FC(10.0%),whereas mean soil resistance to penetration was increased from FA(0.87 MPa)to FB(0.91 MPa)and FC(1.10 MPa).The average infiltration rate was almost similar in FA and FB(FA=76.43 mm h^(-1);FB=77.48 mm h^(-1))and approximately 39%higher than FC(55.79 mm h^(-1)).Thus,although soil density and moisture were different in each passive restoration site,11 year-old passive restoration site showed similar resistance to penetration and infiltration rate to the old(46 years)passive restoration site.These features allowed seeing improvements in hydrological maintenance in the soil and revealed that passive restoration in Cerrado is able to improve the physical features on a soil presenting similar texture,climate and management history.
基金the World Resources Institute for the financial supportthe Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq)for fellowships of the first author(Process Numbers 159972/2018-3)。
文摘The scale of forest and landscape restoration is expected to increase during the UN Decade on Ecosystem Restoration and its contribution to the provision of critical ecosystem services to society.Several models of forest restoration may improve ecosystem services,including soil organic carbon(SOC)storage.A review was carried out to access:(1)the variability of SOC storage between worldwide forest restoration models and,(2)the effects of climate,soil class,soil texture,and vegetation type on SOC storage.We reviewed 119 primary studies with information on SOC and soil texture for different forest restoration models.The restoration models were grouped into four categories:natural regeneration,monocultures,agroforestry,and mixed forest.SOC data was extracted from these four restoration models,other land uses(cropland,bare land,grassland,and natural forest),climate regimes,and soil properties.The SOC storage in the forest restoration models and other land uses at a global scale ranged between 0.1 to 514 Mg ha^(-1).The overall mean value for SOC storage was higher for natural regeneration(112 Mg ha^(-1)),followed by agroforestry(74 Mg ha^(-1)),mixed forest(73 Mg ha^(-1)),and monocultures(68 Mg ha^(-1)).However,the average SOC storage was similar among the four restoration models in the moist warm climate zone.The SOC storage mean value in the moist cool zone was 23%higher than the dry cool zone(81 and 62 Mg ha^(-1),respectively),and 50%higher for the moist warm zone when compared to the dry warm climatic zone(74 and 38 Mg ha^(-1),respectively).The SOC storage of the restoration models was positively related to soil depth(0.59;p<0.01),clay content(0.29;p<0.01),and stand age(0.17;p<0.01).Globally,the mean values of SOC storage were 26,66,and 139 Mg ha^(-1) at zero-10,zero-30,and zero-100 cm depths,respectively.In addition,sandy soils showed smaller mean values of SOC storage than medium to clay soils,especially in deeper soil layers.Furthermore,SOC storage was positively related between restoration models and other land uses(0.93;p<0.01),suggesting a prominent effect of climate and soil properties on SOC.Forest restoration models showed larger SOC storage when compared to croplands and bare land,but in general it was smaller or similar when compared to pasture and natural forest.
基金financially supported by the National Natural Science Foundation of China for Distinguished Young Scholars(41825020)General Program(31870461)+3 种基金the“Hundred Talent Program”of South China Botanical Garden at the Chinese Academy of Sciences(Y761031001)the“Young Top-notch Talent”in Pearl River talent plan of Guangdong Province(2019QN01L763)the Guangdong Basic and Applied Basic Research Foundation(2021A1515012147)the China Scholarships Council(No.202004910605).
文摘Background:Forest restoration has been considered an effective method to increase soil organic carbon(SOC),whereas it remains unclear whether long-term forest restoration will continuously increase SOC.Such large uncertainties may be mainly due to the limited knowledge on how soil microorganisms will contribute to SOC accumulation over time.Methods:We simultaneously documented SOC,total phospholipid fatty acids(PLFAs),and amino sugars(AS)content across a forest restoration gradient with average stand ages of 14,49,70,and>90 years in southern China.Results:The SOC and AS continuously increased with stand age.The ratio of fungal PLFAs to bacterial PLFAs showed no change with stand age,while the ratio of fungal AS to bacterial AS significantly increased.The total microbial residue-carbon(AS-C)accounted for 0.95-1.66% in SOC across all forest restoration stages,with significantly higher in fungal residue-C(0.68-1.19%)than bacterial residue-C(0.05-0.11%).Furthermore,the contribution of total AS-C to SOC was positively correlated with clay content at 0-10 cm soil layer but negatively related to clay content at 10-20 cm soil layer.Conclusions:These findings highlight the significant contribution of AS-C to SOC accumulation along forest restoration stages,with divergent contributions from fungal residues and bacterial residues.Soil clay content with stand age significantly affects the divergent contributions of AS-C to SOC at two different soil layers.
基金financially supported by the Special Fund for Forestry Scientific Research in the Public Interest No.201504406the National Natural Science Foundation of China(Nos.31570705,31500362,31700553)+4 种基金the Shandong Provincial Natural Science Foundation,China(No.ZR2016CP01)the Project of Shandong Province Higher Educational Science and Technology Program(No.J16LF09)China Scholarship Council(No.201809135006)The contribution of S.de-Miguel was supported by the Spanish Ministry of Economy and Competitivity(MINECO)(Grant No.RTI2018–099315-A-I00)by a Serra-Húnter Fellowship provided by the Generalitat of Catalonia。
文摘Background:Robinia pseudoacacia is a widely planted pioneer tree species in reforestations on barren mountains in northern China.Because of its nitrogen-fixing ability,it can play a positive role in soil and forest restoration.After clearcutting of planted stands,R.pseudoacacia stands become coppice plantations.The impacts of shifting from seedling to coppice stands on soil bacterial community and soil properties have not been wel described.This study aims to quantify how soil properties and bacterial community composition vary between planted seedling versus coppice stands.Methods:Nine 20 m×20 m plots were randomly selected in seedling and coppice stands.The bulk soil and rhizosphere soil were sampled in summer 2017.Bulk soil was sampled at 10 cm from the soil surface using a soil auger.Rhizosphere soil samples were col ected using a brush.The soil samples were transported to the laboratory for chemical analysis,and bacterial community composition and diversity was obtained through DNA extraction,16 S r RNA gene amplification and high-throughput sequencing.Results:The results showed that,compared to seedling plantations,soil quality decreased significantly in coppice stands,but without affecting soil exchangeable Mg^(2+) and K^(+).Total carbon(C)and nitrogen(N)were lower in the rhizosphere than in bulk soil,whereas nutrient availability showed an opposite trend.The conversion from seedling to coppice plantations was also related to significant differences in soil bacterial community structure and to the reduction of soil bacterialα-diversity.Principal component analysis(PCA)showed that bacterial community composition was similar in both bulk and rhizosphere soils in second-generation coppice plantations.Special y,the conversion from seedling to coppice stands increased the relative abundance of Proteobacteria and Rhizobium,but reduced that of Actinobacteria,which may result in a decline of soil nutrient availability.Mantel tests revealed that C,N,soil organic matter(SOM),nitrate nitrogen(NO^(-)+(3)-N)and available phosphorus positively correlated with bacterial community composition,while a variation partition analysis(VPA)showed that NO^(-)+(3)-N explained a relatively greater proportion of bacterial distribution(15.12%),compared with C and SOM.Surprisingly,N showed no relationship with bacterial community composition,which may be related to nitrogen transportation.Conclusions:The conversion from seedling to coppice stands reduced soil quality and led to spatial-temporal homogenization of the soil bacterial community structure in both the rhizosphere and bulk soils.Such imbalance in microbial structure can accelerate the decline of R.pseudoacacia.This may affect the role of R.pseudoacacia coppice stands in soil and forest restoration of barren lands in mountain areas.
文摘We investigated the arbuscular mycorrhizal fungi(AMF)status of ten nurseries suitable for restoration of dry evergreen Afromontane forests in Ethiopia.We quantified AMF root colonization(RC)and spore abundance(SA)in seedlings of nine native tree species namely Acacia abyssinica Hochst.ex Benth.,Cordia africana Lam.,Dovyalis abyssinica(A.Rich.)Warb.,H agenia abyssinica J.F.Gmel.,Juniperus procera Hochst.ex Endl.,Millettia ferruginea(Hochst.)Baker,Olea europaea L.subsp.c uspidata(Wall.ex G.Don)Cif.,Podocarpus falcatus(Thunb.)R.Br.ex Mirb.and Prunus africana(Hook.f.)Kalkman.We used the ink and vinegar method to stain AMF in roots.RC levels ranged from 8.00 to 99.67%and were generally higher than the RC levels reported from other similar nurseries in Ethiopia.SA levels ranged from 1 to 25 spores g~(-1)and werecomparable with some reports from the field in Ethiopia but they were lower than levels reported by another similar study.RC was more affected by host species than nursery location,while the reverse was true for SA.The results also showed that nursery management could improve AMF status among seedlings.When all nursery tree species were considered,RC and SA levels were unrelated.No strong correlation existed between the nursery management variables considered and RC or SA.However,considering C.africana,J.procera and P.falcatus separately,RC-age(r_(s)=0.829,P=0.042)correlation for O.europaea and RC-pot diameter(r_(s)=0.820,P=0.046),RC-pot volume(r_(s)=0.928,P=0.008)and SA-age(r_(s)=0.943,P=0.005)correlations for C.africana,were significant,strong and positive.Generally,most of the tree species and particularly,early-mid successional tree species had sufficient AMF inoculum.Hence,only the mid-late successional tree species;J.procera,P.falcatus,and P.africana may require AMF inoculation,preferably,during filed planting.Based on our results,age and pot volume were identified to be important variables potentially affecting RC and SA.To better understand the effects of these and other nursery management variables,additional study is required.We demonstrated for the first time that black Hero ink is suitable for staining root AMF and can be used in future AMF research.
文摘This study aims to analyze temporal changes in land use and land cover change (LUCC) as well as identify areas for natural regeneration and potential areas for forest restoration in the Huasteca region for the period from 1976 to 2007. Changes were quantified in numbers and, additionally, cartography was used to identify and map the main affected areas. Different models based on Geographic Information Systems (GIS) demonstrated that LUCC have occurred on an area of 11718.82 km2, representing 17.84% of the region’s surface. Agriculture and the growth of pasture could be identified as the main human-induced activities that have led to landscape modification. In addition, forest cover is affected by a deforestation rate which is higher than the national average. Further important changes include a change from natural land cover to non-original land cover, affecting an area of 4911.88 km2 in the period from 1976-1993, and an area of 1892.5 km2 in the period from 1993-2002. Smaller changes could be observed for the period from 1993-2002 with an affected area of 1029.78 km2. At the same time, a natural regeneration from nonoriginal to original land cover took place from 1976-1993 on an area of 1318.68 km2, and also on an area of 974.18 km2 between 1993 an 2002. The surface that underwent a natural regeneration of forest cover made up 1932.07 km2. At the same time, an area of 5739.29 km2 for potential forest restoration was identified. Drawing on GIS methods and techniques, the development of thematic maps for land use, land use and land cover changes for the years of analysis (1976-1993-2002-2007) proved to be very adequate for the evaluation and analysis of the land cover and land use change, in particular with regard to the decrease of natural vegetation cover.
基金Key Knowledge Innovation Program of the Chinese Academy of Sciences(KSCX2-SW-132)‘11th Five-Year’Forestry Scientific and Technological Support Program of the Ministry of Science and Technology of China(2008BADB0B0302).
文摘Aims For assisting faster restoration of damaged or severely disturbed coastal ecosystems,selected mangrove species have been planted on previously mangrove-inhabited sites of the tropical and subtropical coasts of southern China.The objective of this study was to understand the stand dynamics of the planted mangroves and their functional traits in comparison with natural mangrove forests under similar site conditions.Methods Species composition,stand density,tree size distribution,and aboveground production were investigated along three transects in a 50-year-old planted mangrove stand and three transects in an adjacent natural mangrove stand in Shenzhen Bay,South China.Measurements were made on tree distribution by species,stand structure,and aboveground biomass(AGB)distribution.Analyses were performed on the spatial patterns of tree size distribution and species association.Important Findings We found that the planted and natural mangrove stands did not differ in stand density,average diameter at breast height(DBH),species composition,and AGB.Spatial distribution of AGB and frequency at species level were also similar between the planted and natural stands.However,the traits in stand structure were more variable in the planted stand than in the natural stand,indicating higher spatiotemporal heterogeneity in the development and succession of planted mangroves.Geostatistical analyses show that both DBH and AGB were spatially auto-correlated within a specific range in the direction perpendicular to coastline.More than 60%of the variance in these attributes was due to spatial autocorrelation.The Ripley’s K-function analysis shows that the two dominant species,Kandelia obovata and Avicennia marina,clumped in broader scales in the natural stand than in the planted stand and displayed significant interspecific competition across the whole transect.It is suggested that interspecific competition interacts with spatial autocorrelation as the underlying mechanism shaping the mangrove structure.This study demonstrates that at age 50,mangrove plantations can perform similarly in stand structure,spatial arrangement of selected stand characteristics and species associations to the natural mangrove forests.
基金supported by the National Natural Science Foundation of China(U1808201,31830016)K.C.Wong Education Foundation(GJTD-2018-07)Liaoning Revitalization Talents Program(XLYC1807102).
文摘Background:Granivore-mediated seed dispersal is susceptible to changes in seed availability and silvicultural management,which alters synzoochorous interactions in the antagonism-mutualism continuum and affects the seed dispersal effectiveness(SDE),and eventually,the plant recruitment.We conducted a whole-year study of seed addi-tion to quantify the granivores-Korean pine(Pinus koraiensis)synzoochorous interactions and the SDE in the same sec-ondary forests with two treatments.Both treatments had seed source limitations:one was caused by the disappear-ance of Korean pine due to the historical disturbance,the other by pinecone harvesting in Korean pine plantations adjacent to the secondary forests.Thinning with different intensities(control,25%,and 50%)were also performed to further explore the synzoochorous interactions and SDE in response to silvicultural management in the second type of forests.Results:Source limitation increased the proportion of pre-and post-dispersal seed predation,and made the granivores-Korean pine interaction shift more towards antagonism,with the estimated SDE of 2.31 and 3.60,respec-tively,for the secondary forests without and with Korean pine.Thinning with different intensities did not alleviate the reactions towards antagonism but altered SDE;granivores occurrence decreased,but the proportion of pre-and post-dispersal seed predation increased,resulting in a fivefold decreased seedling recruitment in 25%thinning(the lowest SDE of 0.26).Conclusion:The source limitation coupling thinning biased the synzoochorous interactions more towards antago-nism and significantly lowered granivore-mediated SDE,which limited the successful recruitment of Korean pine in secondary forests.Forest managers should control pinecone harvesting,protect the synzoochorous interaction,and take into account masting event for Korean pine regeneration in the future.
