Floristic Composition, Population Structure, and Recruitment Status of Plant Species: A Case Study of Farmer-Managed Natural Regeneration Practices in Arid and Semi-Arid Lands in Kenya

The technique of Farmer Managed Natural Regeneration (FMNR) is being promoted as a cost-effective approach for restoring degraded arable dry lands. Its effectiveness has been observed in many countries across the globe, where it is a traditional practice, and is now being encouraged across the African continent. This study aimed to evaluate the impact of FMNR on floristic Composition, Vegetation Structure, and Regeneration Status of woody Plant Species in the severely degraded Central Rift, Kenya. The study systematically assessed how FMNR influenced species composition, vegetation structure and regeneration status from two sample plots involved in FMNR practices. Transect lines and quadrats methods were utilized to collect data, specifically regarding the floristic composition, vegetation structure, and regeneration status of woody plant species. Quadrats and sub-quadrats of varying sizes (10 m by 10 m, 5 m by 5 m, and 1 m by 1 m) were nested along the transect lines for data collection. Furthermore, measurements of tree growth and development, including root collar diameter, diameter at breast height (D130) and heights within the study blocks, were taken. The data was then analyzed using R-software. Results showed a marked progressive increase in numbers of trees, saplings, seedlings, shrubs and herbs in all FMNR sites and reductions in all non-FMNR sites. The study advocates for widespread promotion of the FMNR practice both as an environmental conservation and restoration strategy.

Floristic Composition, Structure and Soil Properties of Mixed Deciduous Forest and Deciduous Dipterocarp Forest: Case Study in Madan Watershed, Myanmar

Patterns of woody regeneration in terms of species composition and diversity were studied in mixed deciduous forest (MDF) and deciduous dipterocarp forest (DDF) in Minbyin reserved forest of Lewe Township. A total of 57 plant species of MDF belonging to 28 families and 342 individuals and 25 plant species of DDF consist of 15 families and 285 individuals were identified. Plant species diversity was quantitatively higher in the MDF (H' = 3.68) compared to the DDF (H' = 2.39). Tectona grandis showed the highest density (30), dominance (4.40 m2) and IVI (27.01) of MDF and Dipterocarpus tuberculatus also composed the highest density (109), dominance (9.02 m2) and IVI (81.87) in DDF. The smallest diameter class (10 - 20 cm) comprised with 29 species, 103 individuals in MDF and 18 species, 85 individuals in DDF. The size class distribution displayed a reverse J-shaped pattern. The largest numbers of species were concentrated in the smallest height class in both investigated forests because of height and diameter distribution is closely related. The total densities of seedlings and saplings were 1219 and 531 ha-1 in MDF and 988 and 444 ha-1 in DDF respectively. Although soil texture of (40 - 50 cm) and (90 - 100 cm) were sandy clay loam in mixed deciduous forest, the other layers of both investigated forests were sandy loam.

Floristic composition and structure of the Kibate Forest along environmental gradients in Wonchi,Southwestern Ethiopia

Dry evergreen montane forests in Ethiopia are severely threatened.The status of species composition and structure of forest vegetation are important indicators to understand the trends of threats on local plant communities.In the present study,we examined the floristic composition and structure of the Kibate Forest,Wonchi Highland,Ethiopia along environmental gradients.Sixty-six(30 m×30 m)plots were established every 100 m interval along altitudinal gradients(2811‒3073 m a.s.l.)in five transect lines for vegetation and environmental data collection.In total,125 vascular plant species belonging to 104 genera and 52 families were identified.Eighteen species(14%)were endemic to Ethiopia and Eritrea.The two most dominant families,Asteraceae(29 species)and Lamiaceae(eight species)accounted for 30%of the total number of species.The highest number of species(54%)was herbs.Four major community types(viz.,Olinia rochetiana-Myrsine melanophloeos,Ilex mitis-Galiniera saxifraga,Erica arborea-Protea gaguedi,and Hagenia abyssinica-Juniperus procera)were identified.The highest species richness,evenness,diversity,and importance value index were in community types 2 and 4.About 82%of the species and all endemic taxa except five were recorded in these two community types.The most dominant woody species were O.rochetiana,E.arborea,Olea europaea subsp.cuspidata,Myrica salicifolia,I.mitis var.mitis,and H.abyssinica with different patterns of population structure.The results show that there was a weak correlation between species richness and altitude.Our findings confirm that environmental variables both with interactions(such as altitude)and without interactions(such as livestock grazing)significantly(p<0.05)affect species richness.Anthropogenic activities and overgrazing by livestock appear to be the main threat in community types 2 and 3.Urgent management practices and conservation measures such as prohibiting forest clearing and overgrazing and planting indigenous trees through community participation should be considered in community types that are rich in endemic species but are highly threatened.

Floristic Composition and Change in Species Diversity over Long Temporal Scales in Upper Bhotekoshi Hydropower Project Area in Nepal

Forest and vegetation of particular ecosystem is generally influenced by external factors especially from development activities. Nepal has been endowed with an immense variety of forest resources with its unique biodiversity. The current study is conducted in the temperate forest of central Nepal to compare the state of vegetation recorded during 1995 with the present condition. To identify floristic composition, species distribution and diversity, same location and same size of quadrates were selected in natural forest and planted or regenerated area as in previous study. Measurement and analytical tools for forest and vegetation reveled a total of 19 species and 341 individuals in 0.14 ha regenerated area and 18 species, 17 genera and 260 individuals in 0.16 ha, natural forest areas. However, in 1995, total 31 individuals of 20 woody species, 18 genera and 15 families were recorded within the sampling plots of 0.16 ha of natural forest. Moreover, Alnus nepalensis is found dominating regenerated area and Caryopteris odorata in natural forests whereas in 1995, Litsea chartacea and Maesa chisia were recorded dominant. The Shannon’s diversity H’ = 2.908, E = 0.970 and Var H’ = -0.00 and Simpsons D = 0.027 recorded in 1995 is found to be with higher values when compared with the analysis of present study. Furthermore, in comparison to 1995 study, this study showed lower basal area and timber volume with declining species diversity. Although, the natural forest is found with higher species composition compared to rehabilitated forest, species of herbs and shrubs were found extensively growing.

Evolution of Floristic Composition and Structural Parameters between Two Management Inventories in a Tropical Forest in the East Cameroon Region

The realization of two management inventories in 2003 and 2020 on the same forest concession made it possible to characterize the floristic composition and to describe some structural parameters on three sites established according to the period of exploitation. Due to the change in the orientation of the lines, it was noted that respectively 82 and 85 species from the first inventory are not found in the second and inversely. A total of 311 species were identified in 2003, compared to 314 in 2020. The density varies from 111 to 140 stems/ha for all the individuals, 19 to 25 for the main species and 15 to 20 for the most exploited species. The decrease in the basal area between the two phases of 12% for all the species and 13% for the main species on the site exploited before the first inventory indicates a persistence of the disturbance for years after logging. It is proposed to supplement the management plans decisions with annual measures based on more complete inventories and to ensure the application of reduced impact logging measures.

Floristic composition,growth temperament and conservation status of woody plant species in the Cameroonian tropical rainforests

Introduction:Cameroon’s tropical rainforests are nowadays strewn with rural forests maintained by local popula‑tions;however,these forests are not officially recognized in the non‑permanent forest domain.Rural forests are non‑delimited riparian areas within the dense moist forest,reserved for rural housing,agricultural activities and agroforestry practices,freely exploited by the local communities for their livelihood without them having any rights to artisanal and commercial logging.This study aimed at contributing to the flora knowledge and the conservation state of woody plant species in rainforests.The study was carried out in two rural forests located in the Eastern and Southern agroforestry zones of Cameroon.Methods:The method adopted for floristic inventories combined a fixed area sampling unit and a variable area sampling unit.Woody individuals with diameter at breast height(dbh)<3.2 cm were counted and shrubs of 3.2≤dbh<10 cm were measured to analyse the understorey,while trees with dbh≥10 cm were measured and identified to characterize the canopy.Results:In the Essiengbot‑Mbankoho rural forest in Eastern Cameroon,468 species belonging to 61 families were recorded in the understory while 227 species belonging to 53 families were identified at the canopy level.A total of 40(7.68%)threatened species,18(3.45%)Near Threatened species and 408(78.31%)Least Concern species were recorded.In the Nbgwassa‑Opkweng rural forest in Southern Cameroon,534 species belonging to 64 families were identified in the understory while 225 species belonging to 43 families were recorded in the canopy.A total of 54(9.69%)threatened species,25(4.49%)Near Threatened species and 421(75.58%)Least Concern species were identified in this forest.Shannon’s diversity indices were above five in the understories and canopies of both forests.Shade‑bearer species were the most represented in the understories while the non‑pioneer light‑demanding and shade‑bearer species were the most abundant in the canopies.Conclusions:Despite the influence of slash‑and‑burn agriculture and subsistence farming practices,rural forests managed by local populations provide opportunities for preserving plant biodiversity.However,the presence of threatened species,pioneer species and non‑pioneer light‑demanding species in these forests is an indicator of mod‑erate and man‑induced disturbances that,in the absence of a forest management plan or sustainable management,may threaten this biodiversity.Legal management of rural forests could help in limiting the anthropogenic activities and pressures on community forests.

Combined community ecology and floristics,a synthetic study on the upper montane evergreen broad-leaved forests in Yunnan,southwestern China

The upper montane evergreen broad-leaved forest in Yunnan occurs mainly in the zone of persistent cloud and has a discontinuous,island-like,distribution.It is diverse,rich in endemic species,and likely to be sensitive to climate change.Six 1-ha sampling plots were established across the main distribution area of the upper montane evergreen broad-leaved forest in Yunnan.All trees with d.b.h.>1 cm in each plot were identified.Patterns of seed plant distributions were quantified at the specific,generic and family levels.The forests are dominated by the families Fagaceae,Lauraceae,Theaceae and Magnoliaceae,but are very diverse with only a few species shared between sites.Floristic similarities at the family and generic level were high,but they were low at the specific level,with species complementarity between plots.Diversity varied greatly among sites,with greater species richness and more rare species in western Yunnan than central Yunnan.The flora is dominated by tropical biogeographical elements,mainly the pantropic and the tropical Asian distributions at the family and genus levels.In contrast,at the species level,the flora is dominated by the southwest or the southeast China distributions,including Yunnan endemics.This suggests that the flora of the upper montane forest in Yunnan could have a tropical floristic origin,and has adapted to cooler temperatures with the uplift of the Himalayas.Due to great sensitivity to climate,high endemism and species complementarity,as well as the discontinuous,island-like,distribution patterns of the upper montane forest in Yunnan,the regional conservation of the forest is especially needed.

Floristic Diversity of Forests of the Northwest Republic of the Congo

The study of structural and tree flora biodiversity of the forest of the Mbomo-Kellé UFA was done on an area of 88.5 ha (0.014% of the total UFA area). The inventory was carried out in plots of 200 m × 25 m (0.5 ha), arranged in a contiguous way along the opened trails in the forest with an equidistance interval of 2 km. 11,012 trees of DBH ≥20 cm were counted, divided into 107 genera, 31 families and 133 species including 121 completely identified and 12 defined only in terms of genus. Data analysis consisted of calculating relative and weighted frequencies, the Shannon and Weaver diversity indexes, Pielou’s evenness index, and the Jaccard and Sorensen similarity indices. Relative frequencies showed that the most representative family in terms of species is the Fabaceae-Caesal piniodeae with 18.05% of species and the most representative in terms of individuals is the Burseraceae with 19.17% of inventoried trees. The principal components analysis allowed to show inter- and intra-block heterogeneities.

Woody plant species diversity and composition in and around Debre Libanos church forests of North Shoa Zone of Oromiya,Ethiopia

Dry afromontane forests are among the most poorly managed and endangered ecosystems.Therefore,we assessed the composition,diversity,and conservation status of woody plant species of the Debre Libanos church forests and surrounding forest lands in Oromiya Regional National State,central Ethiopia in 62 nested circular sample plots spaced 200 m apart along two transect lines.Large circular plots 314 m^(2)were used to sample trees with DBH of at least 10 cm,and subplots of 28.26 m^(2)were laid in each main plot were used to assess saplings and shrubs;a small subplot of 3.14 m2 was used to assess seedlings.In total,70 woody plant species belonging to 62 genera and 43 families were recorded.Of these,59,28 and 32 were in the church,government and private forest types,respectively.The most dominant families were Fabaceae and Verbenaceae,each represented by five species.In the forests considered,trees accounted for 61%,and shrubs with diameter at breast height(DBH)of 1-10 cm accounted for ca.33%.Among growth forms of woody species,shrubs and seedlings,followed by trees constituted much of the density of woody species in all the three ownership types of forests.The church forest had the most species(59)and highest Shannon(3.12)and Simpson(0.92)species diversity indices,and the government and private forests had a nearly similar total number of species and Shannon and Simpson species diversity indices.Most of the species with higher importance value indices(IVI)were indigenous in origin within the church forest(Juniperus procera=82),government forest(J.procera=66)and private forest(Acacia abyssinica=84).The composition,diversity,and population structure of woody species in the church forest were significantly higher than in the other forest lands.However,interventions of the government and private sectors to conserve forest systems in the areas,particularly the government-owned forest and specific species such as Olea europaea need active enrichment plantings due to their limited natural regeneration.Without improved management interventions,livelihood income diversification and ecosystem services obtained from the forest will not be sustainable.

Species Composition and Stand Structure of Primary and Secondary Moist Evergreen Forests in the Tanintharyi Nature Reserve (TNR) Buffer Zone, Myanmar

The habitat structure and floristic composition examined for this study are of great importance, providing a scientific baseline of information for developing a biodiversity database and in supporting crucial information for the management decision-making process of the buffer zones. The primary objective of this study was to examine the current status of species composition and stand structure of moist evergreen forests distributed in the TNR buffer zone. Forest inventory was conducted in the primary moist evergreen forest (~1 ha) and secondary moist evergreen forest (~1 ha). In the TNR buffer zone, 83 species belonging to 31 families in the primary moist evergreen forest and 86 species belonging to 32 families in the secondary moist evergreen forest were found. The most dominant families in the primary moist evergreen forest were Dipterocarpaceae, Sapindaceae, Meliaceae, Myrtaceae, and Myristicaceae;at species level;this forest was composed of Nephelium lappaceum, Myristica malabarica, Nephelium laurium, Aglaia andamanica, and Diospyros peregrine. The most dominant families in the secondary moist evergreen forest were Myrtaceae, Sapindaceae, Euphorbiaceae, Myristicaceae, and Lauraceae, while Nephelium lappaceum, Syzygium claviflorum, Syzygium sp-1, Eugenia oblate, and Myristica angustifolia were the most dominant at the species level. The results of S?rensen’s similarity index based on common species (Ks) and the similarity index based on species dominance (Kd) were observed at about 55% and 75% between the primary and secondary moist evergreen forests. The basal area (51.39 m2.ha-1) of the primary moist evergreen forest was higher than that (44.50 m2.ha-1) of the secondary moist evergreen forest. Between these two forest types, the Shannon-Wiener, the Simpson and the Evenness indices were not significantly different at (p < 0.05). The total number of trees per hectare (n/ha) of the primary and secondary moist evergreen forests were 910 (±184) and 991 (±183). ?

Characteristics and Affinity of Tropical Flora in Southern China

The tropical flora in southern China is represented mainly by three regional flora, i.e. southern Yunnan (southwestern China), southwestern Guangxi (southwestern China) and Hainan Island (southern China). The floristic composition of each is concisely enumerated. Their geographical elements at generic level are analyzed. Furthermore, a comparison of floristic similarities between southern Yunnan and Hainan Island and Malay Peninsula and Brunei of western Malesia is made, based on existing regional flora treatments. The following is concluded: (1) The flora of southern China consists mainly of tropical floristic elements which contribute about 60% at the family level and more than 80 % at the generic level of its total flora. The dominant distribution type of the flora of southern China at the generic level is the tropical Asian distribution pattern. This reveals that the flora of southern China is of tropical nature with a strong tropical Asian affinity; (2) Most of the dominant families from the flora of southern China are also dominant in the Malesian flora. The floristic similarities between the regional flora of southern China and the regional flora of western Malesia are over 70% at the family level and more than 50% at the generic level. This suggests that the tropical flora of southern China belongs to the Malesian floristic region; (3) Situated at the northern margin of tropical Asia, on the other hand it is also obvious that the flora of southern China comprises less strictly tropical elements compared to the Malesian flora, and is consequently only a marginal type of the latter; (4) The close affinity of the flora of southern China to the Malesian flora can be explained by the geological history of southeast Asia.

Shrub Communities and Environmental Variables Responsible for Species Distribution Patterns in an Alpine Zone of the Qilian Mountains, Northwest China

Understanding the factors that drive variation in species distribution is a central theme of ecological research. Although several studies focused on alpine vegetation, few efforts have been made to identify the environmental factors that are responsible for the variations in species composition and richness of alpine shrublands using numerical methods. In the present study, we investigated vegetation and associated environmental variables from 45 sample plots in the middle Qilian Mountains of the northwestern China to classify different community types and to elucidate the species- environment relationships. We also estimated the relative contributions of topography and site conditions to spatial distribution patterns of the shrub communities using the variation partitioning. The results showed that four shrub community types were identified and striking differences in fioristic composition were found among them. Species composition greatly depended on elevation, slope, shrub cover, soil pH and organic carbon. The important determinants of species richness were soil bulk density and slope. No significant differences in species richness were detected among the community types. Topography and site conditions had almost equal effects on compositional variation. Nonetheless,a large amount of the variation in species composition remained unexplained.

Tropical deciduous forest in Yunnan,southwestern China:Implications for geological and climatic histories from a little-known forest formation

In the southern mountain ranges of Yunnan province,China,deep valleys of several large rivers create rain shadows with hot dry summers,and are locally designated tropical;towards the north,notably in the Lancang(Upper Mekong)valley,these regions may experience frost during winter.The woody forest canopy of these valleys is predominantly deciduous,with evergreen elements in the north,where the canopy is open and the forest savanna-like.However,we here present tall forest with a closed deciduous canopy and semi-evergreen subcanopy observed in hot dry valleys of these rivers and their tributaries in the tropical south.The structure and physiognomy of these forests resemble the tall(moist)deciduous forest formation widespread in South Asia and Indo-Burma.Furthermore,these forests are largely composed of tropical elements at both the generic(80%)and the species level(>70%),indicating that these forests are indeed tropical.We originally hypothesized that these isolated forests represent refugia of a pre-Holocene extension of tall(moist)deciduous forest formation of South Asia and Indo-Burma.The sample plot we established to test this hypothesis confirmed that these forests share the structure and physiognomy of the tall(moist)deciduous forest formation;however,the plots also showed that these forests lack the characteristic and dominant species of the formation's Indo-Burmese range.The tree flora,in particular,indicates that both deciduous and evergreen elements are instead mostly derived from the adjacent tropical semi-evergreen forests of tropical southern China;yet they also include an important endemic element,which implies that these forests have survived as refuges possibly since the Pliocene.The exceptional representation of evergreen elements in these forests indicates that they have rarely been subject to hot fires or domestic cattle browsing,adding to the unique nature of the forests and further justifying their strict conservation.

Community ecology and spatial distribution of trees in a tropical wet evergreen forest in Kaptai national park in Chittagong Hill Tracts, Bangladesh

We investigated the floristic composition, woody species diversity and spatial distribution of trees in a tropical wet evergreen forest in Kaptai national park in Chittagong Hill Tracks, Bangladesh. We recorded 25 families, 37 genera, 40 species and 1771 woody individuals in a 0.09 ha plot. Euphorbiaceae and Moraceae were the most species- rich families, and Castanopsis, Ficus and Terminaliawere the most species-rich genera. Bursera serrata Wall. ex Colebr. was the dominant species in terms of highest importance value （13%）. Trema orientalis （L.） B1 was typically a light demanding species as it appeared in the top can- opy with only one individual having the seventh highest IV, but had no regeneration. The expected maximum number of species （Smax） was 140, indicating that many species may invade the forest as the Sm~ is greater than the recorded total number of species. The nature of the disappear- ance and appearance of species in the present forest reflects instability of floristic composition. The values of Shannon＇s index H＇ and Pielou＇s index J＇ （evenness） were 3.36 bit and 0.63, respectively. These values show moderately high species diversity as compared to other subtropical forests in the tropics. In addition, a sample area of 200 m2 in this forest would be sufficient for measuring the diversity indices H＂ and ,/＇, whereas the trend of J＇may indicate the rate of equality of individuals among the different species decreased with increasing area. The distribu- tion pattern for the total stand was completely random. However, the dominant species showed aggregate distribution for small areas, but random distribution for large areas. The spatial association between species showed that the strongest positive interspecific association occurred between Streblus asper Lour. and Castanea indica Roxh. （09 = 0.51）. As a whole, most species were weakly associated with each other, of which 58% species associations were completely negative. The result of cluster analysis showed that species pairs were spatially independent at all or most small clusters; stands of species from all clusters are mosa- ics of complete habitat and pioneer habitat. All patches in this forest community have similar habitat and regeneration niches, which could be a phenomenon for a young growth forest. Thus, the existence of habitat and regeneration niches may be an important factor in the maintenance of diversity in this forest.

Responses of Native Tree Species to Soil Water Stress in a Tropical Forest on Limestone,Vietnam

Forests over limestone in the tropics have received little attention and limestone forests in Vietnam have been overlooked to an even greater extent in terms of tree physiology. In Ba Be National Park, Vietnam, soil water availability in limestone forests seems to be the most limiting factor in the dry season. Therefore, in order to enhance the preliminary knowledge of choosing native tree species for enrichment planting in the restoration zone, characteristics of the 20 native tree species to soil water stress were investigated in a limestone forest. One-ha plot each consisting of twenty-five 20 m × 20 m plots was established in undisturbed forests. All trees ≥ 10 cm DBH were measured in 20 m × 20 m plots, while twenty-five 5 m × 5 m subplots were established in order to sample the regeneration of tree species with a DBH < 10 cm. The Scholander apparatus and freezing point osmometry were used in order to measure the leaf water potential (Ψw) and leaf osmotic potential (Ψπ) of the 20 native tree species, respectively in this study. 61 species belonging to 34 families of all trees with a DBH ≥ 10 cm were recorded in one ha, while 31 species representing 18 families of trees < 10 cm DBH were identified in 625 m2. The 20 species’ leaf water and osmotic potential values revealed significant differences among species. The maximum leaf water potential was not affected by any anticipated sources of variation, while the minimum water potential, however, showed significant variation to soil water stress. The results in the study area emphasized the importance of water factors in influencing tree species distribution;it could be concluded that native species with wide water potential ranges would be better able to withstand water changes and might be thus good candidates for reforestation (enrichment planting) in limestone areas.

Diversity and Structure of Miombo Woodlands in Mozambique Using a Range of Sampling Sizes

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.

Influences of Agricultural Practices in the Canton Erde-Pala Chad Vegetation

The study, conducted in the Canton Erd6-Pala Chad, aims to i） list the different cultural practices, ii） study their impact on the vegetation and iii） determine the methods of co-management of these cultural practices. The surveys were realized on 50 households in the village and phytosociological plants in corn, millet, cotton and peanuts cultures. The data analysis by statgraphic and Excel and Principal Component Analysis （PCA） showed that maize production （1,200 kg/ha） ranked first at the expense of cotton （640 kg/ha）. They negatively affect climate change （temperature increase （26%）, rain drop （20%）, land reclamation （18%） and flooding （12%））. Surveys of vegetation on three acres cotton fields （76.17%）, millet （81.06%）, corn （80.32%） and groundnut （83.56%） showed that there is no significant difference （P = 0.05） on the specific contribution of wood of different types of farming practices. Adventists species herbacious like Thelepogon elegans （27.84%）, Hyptis spicigera （19.31%）, Teramnus labialis （15.86%） have most important contributions in specific cultures. Methods of crop treatments have a destructive impact on the environment and the loss of biodiversity and the invasion of crops by adventists. Co-management, crop rotation, association of cultures, community forest management, agroforestry and training farmers in the use of inputs will reduce the potential risks of farming practices.

Relationship between vegetation structure and microenvironment in Fagus grandifolia subsp.mexicana forest relicts in Mexico

Aims Changes in the structure and composition of forests,whether caused by natural or anthropic events,alter the microenviron-ment,sometimes irreversibly.Since the local environment has a direct impact on basic ecological processes,this has become a key component of research.Mexican beech forests(Fagus grandi-folia subsp.mexicana)in the Sierra Madre Oriental are restricted to sites with specific climate,soils and topography,making them an ideal natural system for ecological research.The objectives of this study were to identify the relationship between the microen-vironment and the tree and shrub structure and composition of Mexican beech forests in the state of Hidalgo,and to compare the floristic similarity of these forests on the country scale using data from seven localities.Methods Specimens were collected for a period of one year at all locali-ties in the state of Hidalgo where beech forests are located.At each locality,five 400 m2 plots were established,and structural attributes(basal area,coverage,density and species richness)and six environmental variables were measured in the plots.The relationship between structure and microenvironment was estimated by simple correlation and canonic correspondence analysis(CCA).in addition,floristic similarity between different beech forest localities in the Sierra Madre Oriental was esti-mated by correspondence analysis(CA).Important Findings Twenty tree species and eight shrub species were identified;at all localities studied F.grandifolia subsp.mexicana dominated the can-opy.The multivariate analysis indicated that(i)in the four localities in the state of Hidalgo,all microenvironmental variables except pH are related to the variation observed in species composition and structure;(ii)the El Gosco locality had both tree and shrub species and microenvironmental factors different from those observed in the Fagus forests at the other localities in the study and(iii)the localities studied in order to draw country-scale comparisons could be divided into three groups by floristic similarity.The first group consisted of the Hidalgo localities,the second of the Veracruz localities,and the third,more different from the others,of the Tamaulipas locality.The results of this study provide the first reference for the relationship between the range of microenvironments and species structure in Mexican beech forests.Microenvironmental conditions in the larger beech forests could be used as a model for designing management and con-servation programs for this plant association.Because of its particular ecological and historical characteristics,this association could serve as an example of biodiversity conservation in Mexico.

Distribution of shrublands in relation to soil and climate in mid-subtropical China

Aims Understanding relationships between vegetation and environments is of importance for ecosystem restoration and management.However,information on how environments influence the floristic patterns of shrublands is lack,especially in the subtropical China.In this study,we explored how environments regulate species composition of shrublands at landscape scale in mid-subtropical China.Methods We investigated species composition and measured the climate and soil environments for 207 shrubland plots in mid-subtropical China(24°39′-30°08′N,108°47′-114°15′E).We applied a hierarchical cluster analysis and indicator species analysis based on the Bray-Curtis similarity index to identify the main shrubland types and employed principal coordinate analysis(PCoA)to explore the relationship between floristic composition and environment.Important Findings We identified four shrubland types occurring in different environmental conditions.Montane shrubland,dominated by species suitable for cool climates(e.g.Rhododendron simsii),were distributed in steep areas at comparatively high altitudes;foothill shrubland,dominated by mesophilous species(e.g.Loropetalum chinense),were distributed in low mountains and hills;pioneer shrubland,dominated by fast grow and short-life cycles species(e.g.Rhus chinensis),were distributed at low altitudes with dense population;and finally,limestone shrubland,dominated by calcicole plants(e.g.Coriaria nepalensis),were distributed in the extensive karst areas.Communities occurring in high pH soils were completely separated from those in low pH soils according to the hierarchical cluster analysis.PCoA ordination associated the four types with distinct edaphic and climatic gradients.Soil pH explained 63.3%of variation in PCoA,followed by soil depth and soil bulk density.

The Distribution Patterns of Timberline and Its Response to Climate Change in the Himalayas

Himalayan region represents the highest and most diverse treeline over the world.As one of the most conspicuous boundaries between montane forests and alpine vegetation,the alpine timberline attracted the interest of researchers for many decades.However,timberline in the Himalayas is understudied compared with European counterparts due to remoteness.Here we review the distribution pattern of timberline and its climatic condition,the carbon and nutrient supply mechanism for treeline formation,and treeline shift and treeline tree recruitment under climate change scenarios.Growth limitation,rather than carbon source limitation is the physiological cause of timberline under the low temperature condition.Nutrient limitation and water stress are not the direct cause of timberline formation.However,more clear local limitation factors are need to integrate in order to enable us to predict the potential impacts and changes caused by human activity and related global change in this sensitive region.