Understory Plant Distribution Research Articles

거문오름 일대 삼나무림 간벌이 하층식물 분포변화에 미치는 영향

This study investigated the change in understory plant distribution to find out the
 effect of cedar(Cryptomeria japonica) thinning on the diversity of plant species in the
 Geomunoreum of J e ju Island, the purpose of which was to restore natural vegetation.
 The vascular plants identified in the thinned plantations for 5 years from 2018 were a
 total of 95 taxa including 51 families, 79 genera, 86 species, 1 subspecies and 8
 variants. This showed a higher number of species compared to 52 taxa in the unthinned
 plantations and 67 taxa in the natural forest stand. The floristic target plants were
 identified: 25 taxa in the thinned plantations, 14 taxa in the unthinned plantations, and
 25 taxa in the natural forest. For 4 years after 2018, an increase of 40 species in the
 thinned plantations showed the highest rate of increase, followed by natural forests with
 33 species and unthinned plantations with 23 species. The species richness increased in
 both thinned and unthinned plantations, 3.16 and 1.10 respectively which is lower than
 4.11 in natural forests. The species diversity with an elapsed time of 6 years after
 thinning rose 3.64 in the thinned plantations, 3.42 in the natural forest and 3.21 in the
 unthinned plantations. The growth of diameter of the breast height was higher than that
 in the unthinned plantations. It is considered that the diversity of plant species in the
 thinned plantations around Geomunoreum is changing similarly to the surrounding natural
 forest as the number and population of newly emerging plant species increase.

Species and Distribution of Understory Plants in Parks

In order to understand the application status of undergrowth ground cover plants in Tianjin parks, the planting area and distribution of understory ground cover plants in aquatic parks, nancui Ping parks and Changhong parks in Tianjin were investigated by the methods of whole garden investigation and sample plot investigation. The results showed that there were 9 species of understory plants in the three parks: Hosta plantaginea (Lam.), Duchesnea indica (Andr.), Sabina rocumbens (endl.), Agave sisalana perr. Ex Engelm., iris lactea, Hemerocallis fulva (L.) L., Buxus megistophylla, Sedum aizoon L. and Rubia cordifolia L., belonging to 9 families 9 Genus. Among them, Hosta plantag nea (Lam.), Duchesnea indica (Andr.) and Sabina rocumbens (endl.) grew well, while iris lactea, Sedum aizoon L. and Rubia cordifolia L. grew poorly. The planting area of Duchesnea indica (Andr.) is the largest, Hemerocallis fulva (L.) L. is the smallest; the ratio of planting area to total park area is the highest, followed by Sabina rocumbens (endl.). The results showed that there were horsta plantaginea (Lam.), Duchesnea indica (Andr.), Sabina rocumbens (endl.), iris lactea, Hemerocallis fulva (L.) L., Buxus megistophylla, and Rubia cordifolia L., Agave sisalana perR. Ex Engelm. And Sedum aizoon L. Duchesnea indica (Andr.) had the highest distribution density, and Hosta plantaginea (Lam.) had the highest frequency. In a word, Horta plantaginea (Lam.) was the most planted species, followed by Duchesnea indica (Andr.) and Sabina rocumbens (endl.), and the planting area of other species was the smallest.

Effects of vegetation restoration and environmental factors on understory vascular plants in a typical karst ecosystem in southern China

Understory vegetation is an important component in most forest ecosystems. It is very important for soil and water conservation in karst region, study on understory will provide valuable information for understanding the interaction mechanism between understory flora and karst environment. Thirty-two plots were sampled in three vegetation types along with a restoration gradient (shrubland, forest–shrub transition, and mixed-species broadleaf forest) in typical karst mountains in Southwest Guangxi, China. Overstory trees, understory vascular plants, soil nutrients, and topographic factors were recorded in each 400-m2 plot. Multivariate statistics were used, including the multi-response permutation procedure (MRPP), indicator species analysis, and canonical correlation analysis (CCA). MRPP showed understory species composition significantly differed among the three vegetation types, with the greatest difference between the shrubland and the mixed forest. Twenty-one understory species were identified as significant indicator species, with 13 species being identified as indicators of the shrubland, two of forest–shrub transition, and six of the mixed forest. Light-demanding herbaceous seed plants were common in shrubland, while shade-tolerant calcicole assembled under the mixed forest. Forward selection of CCA ordination revealed that understory plant distribution was most strongly influenced by elevation, followed by soil pH, the concentration of total potassium and exchangeable calcium, slope aspect, slope degree, and the concentration of available potassium. The result reveals that vegetation types affect understory species composition by modifying understory environments. Elevation affects the spatial distribution of vegetation and soil factors, and then the understory plants. Meanwhile, soil Ca content also plays a key role in the understory species distribution. Understory diversity increased with increasing canopy structure complexity from shrubland to mixed-species forest. Thus, it is necessary to take measures to promote natural vegetation restoration and to protect the mixed forests in degraded karst areas.

Single-tree influence of Tectona grandis Linn. f. on plant distribution and soil characteristics in a planted forest

BackgroundLittle is known about the single-tree influence of Tectona grandis Linn. f. on plant distribution and soil characteristics in Benin City, Nigeria. We investigated the possible single-tree effect of T. grandis on understory plants in an 8-year-old teak plantation at the Moist Forest Research Station. An area of 36.57 m by 60.96 m was marked out and divided into 15 equal-sized subplots containing 10 trees per subplot. Marked distances from the base of a randomly selected tree per subplot were made (0–0.5 m, 0.5–1.0 m and 1.0–1.5 m).ResultsSingle-tree influence of T. grandis was observed in the soil total organic carbon, total nitrogen and soluble phosphorus, where concentrations were higher with 1.5-m radius from the tree than beyond. Moreover, the pH of the topsoil within 1.5 m from the base of the tree was lower (pH 4.4) than beyond 1.5 m from the base of the tree (pH 5.4). Species-specific single-tree effect was also observed on the understory plant distribution likely due to diverse ecophysiological interactions. Within 1.5 m from the tree, plant species abundance, especially of Sida garckeana, Reisantia indica, Momordica charantia and Tridax procumbens were negatively affected. However, the distribution of Eleusine indica around the tree was not negatively influenced. Plant abundance was generally suppressed in Cynodon dactylon, Axonopus compressus, Andropogon gayanus, Commelina diffusa and Euphorbia hirta. Generally, there were more plant species beyond the canopy fringes than within the canopy, indicating inhibitory single-tree effects.ConclusionNot all plant species in close proximity to T. grandis are affected. This is important considering that plant-plant associations affect the quality of forest soils. Generally, more plant species were recorded outside the 1.5-m demarcation than within, an increase in soil organic matter may further enhance such plant species abundance. The impact of T. grandis in forest soil quality is possibly a factor of the outcome of its association with neighbouring plant species. Diverse mechanisms at play may be responsible for the observed effects on soil chemistry. However, a reduction in the soil organic matter and variations in other environmental factors also contributed to observed single-tree effect.

Understory Floristic Diversity in Poplar Plantations in the Dongting Lake Wetlands, China

Large-scale poplar plantations have evoked great concern over their adverse effects on floristic diversity in understory vegetation. The aim of this study was to investigate the effects of tree density on the composition of understory vegetation in poplar (Populus deltoides) plantations in the Dongting Lake wetlands, China. Stand characteristics and soil properties had significant effects on understory plant distribution. Stand density was positively correlated with number of species, Shannon diversity index, and proportions of mesophytes and partial-shade plants but was negatively correlated with the proportions of hygrophytes and heliophytes. Understory light availability was negatively correlated with number of species, Shannon diversity index, and the proportions of mesophytes and partial-shade plants and was positively correlated with the proportions of hygrophytes and heliophytes. Soil water content was negatively correlated with species richness and the proportion of mesophytes and was positively correlated with the proportions of hygrophytes and heliophytes. Compared to low-density stands, high-density stands had a higher number of species and higher proportion of annual/biennial plants, mesophytes, and xerophytes and had lower proportions of perennial plants and hygrophytes during the one-year monitoring period. Therefore, poplar plantations should be managed at lower densities in the Dongting Lake wetlands to conserve the understory flora.

The influence of landform on the understory plant community in a temperate Beech forest in northern Iran

AbstractUnderstanding the factors that determine the distribution of understory plants is important because they represent the largest component of temperate forest plant diversity. We examined the influence of topographic gradients on the distribution of understory plants in Mazandaran Province, northern Iran. Our objective was to determine how the topography of the landscape influenced the composition of understory plant species (cover, diversity, richness, and evenness). We investigated two catena landscape shapes (Λ and V), several different slope positions and their subsequent effects on the composition of the understory herb layer. We established 120 plots that spanned six catenas that varied in shape and slope position (i.e, summit, shoulder, back slope, foot slope and toe slope). We measured the composition of understory plant species populations and calculated diversity using several indices. We found that plant distribution and abundance was strongly related to both catena shape and slope position. Statistical analyses revealed that plant species diversity and richness varied significantly with slope position of the catena, but only diversity varied with catena shape. In addition, significant interactions were found for both diversity and richness. Neither shape nor slope position had a significant effect on evenness alone. We concluded that catena shape and slope position both influence plant distribution, abundance, and biodiversity of the herb layer in these forests by affecting both understory light intensity and soil factors. Our results suggest that the herb layer on Λ‐shaped catenas and V‐shaped landforms were mostly controlled by topography and soil features, respectively.

Gradient analysis and environmental interpretation of understory herb-layer communities in Xiaoshegou of Lingkong Mountain, Shanxi, China

Aims Many past practices in afforestation and forest management were instrumented for addressing the issues of tree species selection, planting regimes and development of overstory structure, but neglected understory vegetation. Our objective was to determine the controlling factors of herb-layer plant distribution and the importance of topography in determining local-scale spatial patterns of herbaceous plants. Methods The occurrence and distribution of herb-layer plants were investigated on 26 plots in the Xiaoshegou catchment of Lingkong Mountain, Shanxi Province, China. Community types were classified using two-way indicator species analysis (TWINSPAN) and the relationship between the distribution and abundance of herb-layer species and environmental gradients was analyzed using the canonical correspondence analysis (CCA) ordination method. Forward selection and Monte Carlo permutation test were used to select the factors important in determining the herb-layer plant distribution. Partial CCA (PCCA) was also performed to partition the variance that was explainable by categorical habitat and biotic factors studied. Important findings The 26 survey plots were classified into six groups characterized by the dominant overstory tree species. The results of CCA ordination reflected the relationship between herb-layer community structure and selective environmental variables. The classification of 26 plots in CCA ordination was consistent with the result of TWINSPAN. Forward selection and Monte Carlo test suggested that stand type, soil nutrients and slope position were the most important factors determining understory plant distribution. PCCA revealed that habitat and biotic factors together explained 42.9% of variance in the distribution of understory herbaceous plants. Habitat factors alone explained 31.8% of the variance, biotic factors alone explained 7.8% of the variance and interactionbetween habitat and biotic factors explained 3.2% of the variance. The partitioning of variance using the PCCA helped with identifying the important habitat factors regulating understory herbaceous plant distribution at the study site. However, the fact that more than half of the variance was unaccounted for by the factors studied suggests that other factors we did not measure could also play a role in determining the occurrence and distribution of herbaceous plants on the forest floor, e.g., human activities and random events. Our study demonstrates the importance of both topography and overstory tree species in determining the occurrence and distribution of herb-layer plant species in temperate forest of mountainous areas.

Effects of forest patch type and site on herb-layer vegetation in a temperate forest ecosystem

Development of strategies and schemes for adaptive forest management requires sound understanding on the controls and contributing factors of forest productivity and biological conservation. Understanding the factors determining the distribution of understory plants is important for biological conservation because the herb-layer vegetation represents the largest component of biodiversity in most forest ecosystems. We examined the effects of tree canopy and site on herb-layer vegetation in 40 plots representing three contrasting forest patch types, i.e. Pinus tabuliformis Carr (pine forest), Quercus liaotungensis Koidz (broadleaf forest), and P. tabuliformis–Q. liaotungensis mixture (mixed-wood forest), at elevations ranging from 1542m to 1734m in a temperate forest of North China. The importance of the overstory and other biotic and site factors in controlling understory species composition and diversity was quantitatively assessed by the method of constrained ordination (CCA). Analysis with multi-response permutation procedure (MRPP) reveals significant differences in species composition of the herb-layer among the three contrasting forest patch types; each forest patch type supports a distinct plant community in the herb-layer as assessed by composition and importance value of the representative species. Forward variable selection shows that litter mass, aspect, and canopy openness are most important in explaining species composition and diversity of the herb-layer. Both species richness and Shannon–Wiener index (H′) increase as the aspect orients southward and the sampling plot moves higher on slope. To a lesser extent, increasing canopy openness is associated with slightly decreasing species diversity in the herb-layer. Mixed-wood forest is found to have highest species richness and lowest Whittaker’s measure of inter-site variability in species composition (i.e. β-diversity) in the herb-layer among the three forest patch types, highlighting the ecological significance of the mixed-wood forest in maintaining biodiversity and community stability in temperate forest ecosystems. The outcome of this study suggests that management practices should consider retaining the natural intermix of canopy patches for conservation of biodiversity in the herb-layer of forest ecosystems.

Variation in Vegetation Structure and Soil Properties, and the Relation Between Understory Plants and Environmental Variables Under Different Phyllostachys pubescens Forests in Southeastern China

Biodiversity maintenance and soil improvement are key sustainable forestry objectives. Research on the effects of bamboo forest management on plant diversity and soil properties are therefore necessary in bamboo-growing regions, such as southeastern China's Shunchang County, that have not been studied from this perspective. We analyzed the effects of different Phyllostachys pubescens proportions in managed forests on vegetation structure and soil properties using pure Cunninghamia lanceolata forests as a contrast, and analyzed the relation between understory plants and environmental variables (i.e., topography, stand and soil characteristics) by canonical correspondence analysis (CCA). The forest with 80% P. pubescens and 20% hardwoods (such as Phoebe bournei, Jatropha curcas, Schima superba) maintained the highest plant diversity and best soil properties, with significantly higher plant diversity than the C. lanceolata forest, and better soil physicochemical and biological properties. The distribution of understory plants is highly related to environmental factors. Silvicultural disturbance strongly influenced the ability of different bamboo forests to maintain biodiversity and soil quality under extensive management, and the forest responses to management were consistent with the intermediate-disturbance hypothesis (i.e., diversity and soil properties were best at intermediate disturbance levels). Our results suggest that biodiversity maintenance and soil improvement are important management goals for sustainable bamboo management. To achieve those objectives, managers should balance the inputs and outputs of nutrients and protect understory plants by using appropriate fertilizer (e.g., organic fertilizer), adjusting stand structure, modifying utilization model and the harvest time, and controlling the intensity of culms and shoots harvests.

Hydrastis Canadensis L. (Ranunculaceae) Distribution does not Reflect Response to Microclimate Gradients across a Mesophytic Forest Cove

Spatial patterns of understory plant distribution can reflect availability of suitable abiotic microsites. Hydrastis canadensis is a native, herbaceous perennial whose distribution may be constrained by microsite availability. We planted 5 transects each on south- and north-facing cove hillsides with clonally derived rhizomes of H. canadensis. Transects were spaced 20, 40, 60, 80, and 100 m from a third-order stream. Because the transect 20 m from the stream on the south-facing hillside was adjacent to a natural H. canadensis patch, this transect was postulated to represent suitable habitat. We tested the effects of aspect and distance from stream on phytometer growth measures (survival, leaf area, and both rhizome and leaf area relative growth rates). We also monitored temperature, humidity, and light, then quantified environmental distances for these measures between each transect location and the transect in suitable habitat. Plant growth measures were then regressed on these distances to test hypotheses about factor effects. Neither survival nor relative growth rates depended on aspect or distance from the stream, although leaf area was greater on the north-facing aspect in both years and increased with proximity to the stream in 2003. Rhizome relative growth rate did not depend on any of the environmental distance measures, although leaf area change depended on cumulative light, increasing as the environmental distance from the suitable site increased. The relatively weak association between environmental variation across the forested cove reinforces other studies suggesting that H. canadensis has a relatively broad ecological niche, and its rarity is unlikely due to lack of availability of suitable habitat.

Influence of light and soil moisture on Sierran mixed-conifer understory communities

Sierra Nevada forests have high understory species richness yet we do not know which site factors influence herb and shrub distribution or abundance. We examined the understory of an old-growth mixed-conifer Sierran forest and its distribution in relation to microsite conditions. The forest has high species richness (98 species sampled), most of which are herbs with sparse cover and relatively equal abundance. Shrub cover is highly concentrated in discrete patches. Using overstory tree cover and microsite environmental conditions, four habitats were identified; tree cluster, partial canopy, gap, and rock/shallow soil. Herb and shrub species were strongly linked with habitats. Soil moisture, litter depth and diffuse light were the most significant environmental gradients influencing understory plant distribution. Herb cover was most strongly influenced by soil moisture. Shrub cover is associated with more diffuse light, less direct light, and sites with lower soil moisture. Herb richness is most affected by conditions which influence soil moisture. Richness is positively correlated with litter depth, and negatively correlated with direct light and shrub cover. Disturbance or management practices which change forest floor conditions, shallow soil moisture and direct light are likely to have the strongest effect on Sierran understory abundance and richness.

The influence of past land‐use on understory plant distributions in a near‐natural deciduous forest in Denmark

In regions with a long cultural history, past land‐use may strongly determine floristic composition in seemingly natural vegetation. Here we examine if past land‐use affects understory plant distribution in near‐natural forest in a historically and environmentally heterogeneous setting, namely the 17 ha freshwater island of Borgnr (Denmark). In 107 randomly located 100 m2 plots we recorded species composition and various environmental variables. The plots were classified into three groups according to past land‐use: (1) Disturbed sites close to 12th and 20th century ruins and associated open areas; (2) formerly grazed meadow areas; and (3) forested sites without indications of strong anthropogenic influence. Past land‐use, environmental variables and species traits were used to interpret floristic gradients. Unconstrained and constrained ordinations clearly separated plots with different past land‐use, and showed that the main floristic gradients on Borgø correlated with hydrological‐edaphic conditions and past land‐use. Partial constrained ordination using the environmental parameters as covariables showed that past land‐use had a unique influence on floristic composition.

Overstory influences on herb and shrub communities in mature forests of western Washington, U.S.A.

Understanding the relationships between forest overstory and understory communities is essential for predicting changes in the abundance and distribution of understory plants through successional time and in response to forest management. We used correlation analysis, multiple regression, and nonparametric models to explore the relationships between overstory characteristics (canopy cover, stand density, and tree-size distributions) and the abundance of species in the herb and shrub layers in mature forests of western Washington. Overstory variables explained >50% of the variation in the mean response of total shrub cover and ca. 50% of the variation in cover of Acer circinatum Pursh (the most common shrub species) and late-seral herbs (species reaching their greatest abundance in late-successional forests). Stronger relationships (80-90% variance explained) were found between overstory variables and the maximum cover of total shrubs, A. circinatum, total herbs, and each of three functional groups of herbaceous species. These empirical relationships represent both direct resource limitations and time-dependent responses for which overstory characteristics may be surrogates. Models of maximum abundance yielded the most consistent results, suggesting the relative importance of different overstory variables as limiting factors for understory response, although these limiting factors have different effects on plants with different life-history strategies.

Overstory influences on herb and shrub communities in mature forests of western Washington, U.S.A.

Understanding the relationships between forest overstory and understory communities is essential for predict - ing changes in the abundance and distribution of understory plants through successional time and in response to forest management. We used correlation analysis, multiple regression, and nonparametric models to explore the relationships between overstory characteristics (canopy cover, stand density, and tree-size distributions) and the abundance of species in the herb and shrub layers in mature forests of western Washington. Overstory variables explained >50% of the varia- tion in the mean response of total shrub cover and ca. 50% of the variation in cover of Acer circinatum Pursh (the most common shrub species) and late-seral herbs (species reaching their greatest abundance in late-successional for - ests). Stronger relationships (80-90% variance explained) were found between overstory variables and the maximum cover of total shrubs, A. circinatum, total herbs, and each of three functional groups of herbaceous species. These em- pirical relationships represent both direct resource limitations and time-dependent responses for which overstory charac - teristics may be surrogates. Models of maximum abundance yielded the most consistent results, suggesting the relative importance of different overstory variables as limiting factors for understory response, although these limiting factors have different effects on plants with different life-history strategies. Resume : Pour predire les changements dans l'abondance et la distribution des plantes du sous-bois au cours de la suc- cession et en reponse a l'amenagement forestier, il est essentiel de comprendre les relations entre l'etage forestier do- minant et les communautes du sous-bois. Les auteurs ont utilise l'analyse de correlation, la regression multiple et les modeles non parametriques pour explorer les relations entre les caracteristiques de l'etage dominant (recouvrement de la canopee, densite du peuplement, distributions de la dimension des arbres) et l'abondance des especes dans les strates

Vegetation responses to landscape structure at multiple scales across a Northern Wisconsin, USA, pine barrens landscape

Increasing awareness of the importance of scale and landscape structure to landscape processes and concern about loss of biodiversity has resulted in efforts to understand patterns of biodiversity across multiple scales. We examined plant species distributions and their relationships to landscape structure at varying spatial scales across a pine barrens landscape in northern Wisconsin, U.S.A. We recorded plant species cover in 1 X 1 m plots every 5 m along a 2575 m transect, along with variables describing macro- and micro-landscape structure. A total of 139 understory plant species were recorded. The distributions of many species appeared to be strongly associated with landscape structural features, such as distinct management patches and roads. TWINSPAN and detrended correspondence analysis (DCA) identified three groups of species that overlapped extensively in the ordination, possibly reflecting the relatively homogeneous nature of disturbance in the pine barrens landscape. Distribution of understory plants did not reflect all of the patch types we identified along the transect; plot ordination and classification resulted in three five plot groups that differed in niche breadth. Wavelet transforms showed varying relationships between landscape features and plant diversity indices (Shannon-Weiner, Simpson''s Dominance) at different resolutions. Wavelet variances indicated that patterns of Shannon diversity were dominated by coarse resolutions ranging from ~900-1500 m, which may have been related to topography. Patterns of Simpson''s Dominance were dominated by ~700 m resolution, possibly associated with canopy cover. However, a strong correspondence between overstory patch type and diversity was found for several patch types at ranges of scales that varied by patch type. Effects of linear features such as roads were apparent in the wavelet transforms at resolutions of about 5-1000 m, suggesting roads may have an important impact on plant diversity at landscape scales. At broad scales, landscape context appeared more important to diversity than individual patches, suggesting that changes in structure at fine resolutions could alter overall diversity characteristics of the landscape. Therefore, a hierarchical perspective is necessary to recognize potential large-scale change resulting from small-scale activities.

Modeling the spatial structure of topical forests

The spatial structure of tropical forest stands under different management conditions was modeled as a series of different spatial point processes. Spatial patterns were first assessed by K-function analyses to help choose a point process appropriate for observed patterns. The homogenous Neyman–Scott process accurately described live tree distribution in clear cut areas, where tree patterns tended to be aggregated. Parameters were estimated by minimizing Diggle's modified least squares criterion, and goodness-of-fit was assessed by comparison to confidence envelopes constructed by Monte Carlo simulation. Parameter estimates can be interpreted to help understand the ecological processes influencing re-colonization of disturbed areas. The inhomogeneous Poisson process was investigated for simulating the spatial pattern of ingrowth trees in lower canopy strata. The intensity function of this process was inversely proportional to variables representing canopy density. As assessed by Monte Carlo generation of confidence envelopes, the inhomogeneous Poisson process successfully portrayed the influence of canopy structure on understory plant distribution in most stands. Tree mortality was modeled as a thinning process in which the probability of individual tree mortality was conditional on subject tree attributes and competitive environment. The thinning function took the form of a generalized linear model with a binomial error distribution and logit link function. In most stands, tree neighborhood variables were powerful predictors of mortality, but they were not important predictors in all plots. This suggests that the surrounding forest structure of a subject tree has considerable influence on its morality, but competition is not the sole cause of tree morality in tropical forests.