Foliage Height Diversity Research Articles

京都府南山城地域の二次林における鳥類群集と植生構造の関係

We conducted bird surveys (breeding and wintering seasons) and vegetation surveys on thirty plots in secondary forests in Minami-Yamashiro area, Kyoto Prefecture, to determine the effects of vegetation factors on forest bird communities. We carried out regression analyses to evaluate the factors influencing the bird species richness for each season. The overall bird species richness became higher with the increase of the basal area in the breeding season, and so it did with the increase of the tree height in the wintering season. The factors that explained species richness of nesting-site guilds were the basal area for the canopy nesters; the tree height for the hole nesters; and the foliage height diversity for the ground nesters. Those of the forage-on-tree guild were the basal area in the breeding season and the tree height in the wintering season.

Effects of habitat structure and shrub encroachment on bird species diversity in arid savanna in Northern Cape province, South Africa

Bird community diversity was assessed in semi-arid savanna in the Northern Cape province of South Africa and related to vegetation diversity and foliage height diversity. As this is an area in which shrub encroachment is common, the effects of shrub or bush encroachment on bird species diversity were specifically addressed. An experiment in which the dominant encroaching species, Acacia mellifera, was removed from ten 1 ha plots was used and compared with ten controls. A strong positive association with foliage height diversity was shown. No effect of experimental removal of the dominant encroacher, A. mellifera, on bird species diversity or species richness was found. However, four species increased in relative abundance in cut plots and two species decreased in relative abundance in these plots.

High seedling recruitment of indigenous tree species in forest plantations in Kakamega Forest, western Kenya

Tree plantations are often used to compensate for the destruction and conversion of natural forests in the tropics. An important question is whether these plantations allow for the regeneration of indigenous tree species and are expected to transform into more natural forests in the future. To evaluate the potential of differently managed forest types for seedling recruitment of indigenous tree species we studied structural characteristics as well as tree and seedling communities in stands of natural forest, different types of tree plantations and secondary forest in Kakamega Forest, western Kenya. Forest types differed considerably in structural characteristics and tree composition with stands of natural forest significantly differing from all other forest types in vertical foliage height diversity and number of late-successional tree species. By contrast, total seedling species richness and number did not differ among the forest types. Yet, number of seedlings of late-successional species decreased from natural forest and plantations of a mixture of indigenous tree species towards monocultures and secondary forests while number of seedlings of early-successional species increased in the same order. A joint Principal Component Analysis (PCA) corroborated higher similarity among seedling communities than among tree communities. Our results indicate a convergence of recruiting seedling communities in different forest management types suggesting that tree plantations might buffer forest loss to a certain extent and may have the potential to develop into more natural forest over time.

Breeding bird community composition in different successional vegetation in the montane coniferous forests zone of Taiwan

To examine the relationship between forest succession following fire and the composition of bird communities, we investigated the vegetation structure, bird population density, foraging behavior and guild structure in bamboo grasslands (11 years since the last fire), pine savanna (41 years), pine woodland (58 years), old-growth hemlock forest (never burned), and old-growth spruce forest (never burned) in the Tatachia area of central Taiwan. Canopy height, total foliage cover, tree density, total basal area of tree, total basal area of snags, foliage height diversity, and tree species richness all increased with successional age. However, shrub cover peaked in intermediate successional stages. The vertical profile of foliage cover was more diverse in later successional forests, which had more breeding bird species and ecological guilds. All the breeding bird species recorded in early and intermediate stages were also found distributed in the late successional forests. Because Taiwan has high precipitation and humidity, and most forest fires in Taiwan are caused by human activities, forest fires and large areas of early successional vegetation were probably rare in the mountain areas of Taiwan prior to the arrival of humans. Therefore, bird species have not had enough time to adapt to areas with early or intermediate successional vegetation. Moreover, late successional forests host all the major plant species found in the early and intermediate stages and have higher foliage height diversity index, which was positively correlated with the bird species richness and bird species diversity index in this study. As a result, all breeding bird species and guilds in the area can be found in late successional forests. Efforts for conserving avian diversity in Taiwan should focus on protecting the remaining native old-growth forests.

The use of airborne lidar to assess avian species diversity, density, and occurrence in a pine/aspen forest

Vegetation structure is an important factor that influences wildlife-habitat selection, reproduction, and survival. However, field-based measurements of vegetation structure can be time consuming, costly, and difficult to undertake in areas that are remote and/or contain rough terrain. Light detection and ranging (lidar) is an active remote sensing technology that can quantify three-dimensional vegetation structure over large areas and thus holds promise for examining wildlife-habitat relationships. We used discrete-return airborne lidar data acquired over the Black Hills Experimental Forest in South Dakota, USA in combination with field-collected vegetation and bird data to assess the utility of lidar data in quantifying vegetation structural characteristics that relate to avian diversity, density, and occurrence. Indices of foliage height diversity calculated from lidar data were positively and significantly correlated with indices of bird species diversity, with the highest correlations observed when foliage height diversity categories contained proportionally more foliage layers near the forest floor (<5 m). In addition, lidar-derived indices of vegetation volume were significantly correlated with bird density. Using lidar-derived vegetation height data in combination with multispectral IKONOS data, we delineated five general habitat types within the study area according to the presence of prominent vegetation layers at lower levels of the forest and predominant tree type (deciduous or conifer). Habitat type delineations were tested by examining the occurrence and relative density of two bird species common to the study area that prefer lower level vegetation for foraging and nesting. Dark-eyed Juncos were significantly associated with the 0.5–2.0 m high vegetation layer in pine-dominated stands, and Warbling Vireos were significantly associated with this same layer in aspen-dominated stands. These results demonstrate that discrete-return lidar can be an effective tool to remotely quantify vegetation structural attributes important to birds, and may be enhanced when used in combination with spectral data.

The efficacy of small-scale conservation efforts, as assessed on Australian golf courses

Habitat remnants on urban green-space areas (i.e. parks, gardens and golf courses) sometimes provide refuge to urban-avoiding wildlife, leading some to suggest these areas may play a role in wildlife conservation if they are appropriately designed and managed. The high densities observed on some green-space areas may however be attributed to external influences. Localised efforts to enhance the habitat value of urban green-space areas may therefore have little more than a cosmetic effect. This study investigated environmental factors influencing bird, reptile, mammal and amphibian diversity on Australian golf courses to assess the efficacy of small-scale conservation efforts. Abundance and species richness did not simply reflect local habitat qualities but were instead, partly determined by the nature of the surrounding landscape (i.e. the area of adjacent built land, native vegetation and the number of connecting streams). Vertebrate abundance and species richness were however, also associated with on-site habitat characteristics, increasing with the area of native vegetation (all vertebrates), foliage height diversity and native grass cover (birds), tree density, native grass cover and the number of hollows (mammals), woody debris, patch width and canopy cover (reptiles), waterbody heterogeneity and aquatic vegetation complexity (frogs). Localised conservation efforts on small land types can benefit urban-avoiding wildlife. Urban green-space areas can provide refuge to urban-avoiding vertebrates provided combined efforts are made at patch (management), local (design) and landscape (planning) scales.

Relationship between diversity of forest plant and community dynamics in eastern mountain area of Heilongjiang Province, China

The biodiversity was studied in 26 communities with different structures in Maoershan National Park and Liangshui Natural Reserve of Northeast Forestry University in Heilongjiang Province. China. Composition index (CI) was taken as a parameter to quantify the community dynamics, which can nicely describe forest community dynamics, meanwhile, the relationship between diversity and community dynamics were also investigated and analyzed. Results showed that the total number species of community, richness, evenness, and Shannon-Wiener diversity index were obviously different in every community. The richness decreased with the increasing CI of every community, which means richness was in inverse proportion to community dynamics. The Shannon-Wiener index of every community increased from the initial stage to the middle stage of succession, and then decreased in the climax stage. The coverage weighted foliage-height diversity index increased along with the increase of CI, which was similar as the pattern diversity.

Effects of excessive harvest on plant species and forest structures in a subtropical evergreen forest of Castanopsis sieboldii

The subtropical evergreen forest of Yanbaru in the northern district of Okinawa is famous for its treasury of biodiversity. For the most part, biodiversity continues to persist in abundance, especially in the forests inside the US Marine base - The Jungle Warfare Training Center (JWTC), which escaped the excessive harvest after WWII. However, these forests also experienced excessive use of trees and shrubs during the war. Now that the return of more than half the JWTC area is close at hand, it is important to clarify the effects of this pre-1945 impact in order to develop a biological conservation plan. Accordingly, plant species and forest structures in evergreen broadleaved forests dominated by Castanopsis sieboldii, the major forest type in Yanbaru, were investigated. The impact of severe use during the war was not detected in species richness and species composition. However, stand volumes and foliage height diversity in forests that were severely used before 1945 were found to be less developed. Rehabilitation of these severely used forests of C. sieboldii is an important mission for biological conservation, because many indigenous animals selectively inhabit old-grown forests of C. sieboldii with highly developed structures.

Bird community composition in an actively managed savanna reserve, importance of vegetation structure and vegetation composition

The mosaic of trees, shrubs and open grassland in mesic African savannas is highly dynamic and strongly influenced by mammal herbivory and fire. We investigated the bird fauna in four different savanna habitats to help assess the impacts of vegetation change on this component of faunal diversity. Birds were censused, plant species were identified and vegetation structure was measured in four different vegetation types (Acacia nilotica woodland, Acacia nigrescens woodland, broadleaf thicket and open grassland) in the Hluhluwe-Umfolozi Park in northern KwaZulu Natal, South Africa. Multivariate ordination analyses were used to determine the relative importance of vegetation structure and floristic composition in defining bird assemblages. The bird communities of the grasslands, the acacia woodlands, and the broadleaf woodlands were clearly separated on the first axis of the detrended canonical correspondence analysis (DCCA). Canopy cover and foliage height diversity (FHD) were strongly correlated with the first axis of DCCA, possibly reflecting a secondary successional series from grassland to woodland, known as bush encroachment. Floristic composition (based on presence–absence data only) seemed to be less important for bird community composition than vegetation structure. The results indicate that changes in vegetation structure, caused by bush encroachment, could cause concomitant changes in bird community composition.

Avian richness and abundance in temperate Danish forests: tree variables important to birds and their conservation

Many studies on avian diversity and forest structure have focused onfiner scale forest variables such as foliage height diversity, foliagediversity, foliage density, vertical distribution of vegetation and horizontalvegetation density. From a conservation and forestry operational point of viewit would be of great interest if tree variables influenced directly by forestrymanagement decisions also had significant influence on avian richness andabundance. The species, age and size of a tree are examples of such treevariables. A great number of studies also have focused on avian diversityindices to reveal relationships with vegetation variables. However, it may bemore appropriate for foresters and conservation officers to operate withrichness and abundance measures directly, because indices complicateinterpretations on the relative importance of the two variables (richness andabundance) constituting the index. Fourteen managed temperate forests in Denmarkwere investigated for avian species richness and abundance and related tomeasures on different tree variables influenced directly by forestry managementdecisions. A rapid assessment method of avian richness and abundance wasemployed. It consisted of point-counts of bird richness and abundance within 1km2 of forest. General linear models were tested byanalyses of variance statistics to reveal the tree variables most important toavian richness and abundance. It was found that more old trees, more treespecies and more tree size-classes correlated with more bird species andindividuals. However, some variation in bird richness and abundance was alsorelated to site quality and/or chance colonization. Moreover, it was shown thatthe guild of cavity-nesting birds correlated positively to age of tree stand.The potential number of bird species in Danish forest is similar to that innearly pristine forest in Poland, and much larger than that recorded in any ofthe forests investigated. Together with the results above, this indicates a highpotential for squeezing in more avian species in a higher quality forest from abiodiversity point of view. Modern Danish forestry affects tree variablesinfluenced directly by forestry management decisions. Such tree variables havegreat influence on avian richness and abundance, but simple measures in forestrypractices can be taken to enhance the conservation of bird richness andabundance.

Induced Spatial Heterogeneity in Forest Canopies: Responses of Small Mammals

We hypothesized that creating a mosaic of interspersed patches of different densities of canopy trees in a second-growth Douglas-fir (Pseudotsuga menziesii) forest would accelerate development of biocomplexity (diversity in ecosystem structure, composition, and processes) by promoting spatial heterogeneity in understory, midstory, and canopy, compared to typical managed forests. In turn, increased spatial heterogeneity was expected to promote variety in fine-scale plant associations, foliage height diversity, and abundance of small mammals. Three years following treatment, understory species richness and herb cover were greater with variable-density thinning than without. Midstory and canopy species did not have time to develop significant differences between treatments. Variable-density thinning resulted in larger populations of deer mice (Peromyscus maniculatus), a species associated with understory shrubs; creeping voles (Microtus oregoni), a species associated with herbaceous vegetation, and vagrant shrews (Sorex vagrans), a species usually associated with openings but common in old growth. No forest-floor small-mammal species, including those associated with old-growth forest, declined in abundance following variabie-density thinning. Annual variation in population size was not related to treatment. Variable-density thinning may accelerate the development of biocomplexity in second-growth forest by promoting spatial heterogeneity and compositional diversity in the plant community, increasing diversity and abundance of small mammals, and similarly affecting other vertebrate communities. When combined with long rotations, legacy retention, and management for snags and coarse woody debris, variable-density thinning has broad applicability to enhance biodiversity in managed Douglas-fir forests across the Pacific Northwest.

Tree shape, forest structure and diversity of drosophilid community: Comparison between boreal and temperate birch forests

Some models, based on the latitudinal variation in sun angle distribution, predict that trees at high latitudes have narrowly conical crowns and constitute simple‐layered forests, whereas trees at low latitudes have shallowly dome‐shaped and form more structurally complex multilayered forests. There is a hypothesis that structurally complex habitats can harbor potentially more species than simple ones. In this study, we examined latitudinal correlations between tree shape, forest structure and diversity in drosophilid communities, comparing boreal and cool‐temperate forests. We selected secondary birch forests with a common canopy tree species, white birch (Betula platyphylla Sukatchev), as study sites. The crown shape of white birch tended to be spherical in the cool‐temperate forest, but narrowly conical in the boreal forest. The foliage structure differed between the two forests. The cool‐temperate forest was characterized by a clearly two‐layered structure, whereas foliage in the boreal forest was less clearly stratified, being distributed somewhat continuously from the ground to the canopy at lower densities. The structural complexity expressed by foliage height diversity was greater in the cool‐temperate forest than in the boreal forest. Various measures of drosophilid diversity were higher in the cool‐temperate forest than in the boreal forest, probably resulting from the impoverishment of the canopy subcommunity in the boreal forest. Thus, a physical environmental factor (i.e. the angle of solar inclination) could be a potentially important factor in structuring latitudinal patterns of sylvan animal communities through changes in plant structure at the individual and community levels.

Relative densities and habitat utilization of non-utilized, terrestrial gamebird populations in a natural savanna, South Africa

The objective of this study was to determine the relative population densities and habitat utilization of gamebird species in relation to plant communities, the amount of ecotone, and vegetation structure. The distribution of five terrestrial gamebird populations was monitored for 12 months in the Nyslvley Nature Reserve, South Africa. Only three species, Swainson's francolin (40.44% of the total gamebird population), crested francolin (10.41%) and guineafowl (43.94%), were found in significant numbers. Group sizes of these gamebird populations were typical for the species. The high amount of edge or ecotone (total amount of edge (DI) = 0.26), the short (9.36 cm) and evenly structured grass layer (mean Foliage Height Diversity (FHD) = 0.38), and a mosaic of open areas and termitaria thickets rendered the Sporobolus ioclados–Acacia tortilis Savanna suitable for gamebirds. The adjacent seasonally inundated floodplain was also utilized to some extent, mainly by Swainson's francolin. It appears that visibility is more important for gamebirds than a high diversity in grass structure. Also, a mosaic of feeding areas and cover makes an area suitable for terrestrial gamebirds. Of the gamebird species found in the reserve, only the Swainson's francolin, crested francolin and guineafowl populations had the potential to be harvested.

Accuracy of the MacArthur-Horn method for estimating a foliage profile

To estimate three-dimensional distribution of foliage which affects microclimate in forests and habitat structure of biotic community, we examined the accuracy of the MacArthur-Horn method at various sampling scales and points in a deciduous broad-leaved forest by using a large scaffolding and direct observation. The coefficient of determination of the relationships between estimates and observed values decreased with increasing complexity of foliage profile. The accuracy of estimating the foliage distribution did not change with the sampling scale when the total number of sampling points was constant at 64 points. Therefore, it is necessary to adjust the number of sampling points according to the sampling scale in a forest where foliage height diversity is high. On the other hand, the accuracy increased asymptotically with increasing sampling scale when the number of sampling points per unit area was keep constant (ca. 64 points per 1.8 m × 1.8 m). We can get a suitable sampling area which the accuracy of estimates remains constant. The minimum scale for estimating correct foliage profile was about 80 m 2, and its coefficient of determination was 0.855. Therefore, we will be able to estimate three-dimensional foliage distribution of individual trees or species and the heterogeneity of the foliage profile at any scales in accordance with the aims of study if we design the sampling points and the size of sampling scale into consideration.

Bird-Habitat Relationships in a Vegetational Gradient in the Andes of Central Chile

An unusual pattern has been described in Patagonian forests, where bird species diversity seems to be inversely correlated with vegetation complexity. To test the occurrence of this pattern in the northern Nothofagus forests of central Chile, a study was conducted at the Ñuble National Reserve during the austral summers of 1994 and 1995. Twenty-nine plots were set along a vegetational gradient. In each plot, the density of all diurnal bird species was estimated, and the vegetation composition and structure were measured. The highest and the lowest bird species diversity were found in semideciduous scrub habitat and Poaceae steppes, respectively. In nongrassland sites, no vegetation variable explained bird species richness or diversity. Total foliage volume and foliage height diversity were significantly correlated with bird species diversity in the nonforest sites but not in the forested areas. However, foliage height diversity significantly explained the variation of bird density and bird species richness in the forest sites. The presence of the tree Nothofagus obliqua was positively correlated with bird diversity and insectivore density. The patterns observed at Nuble lie between the traditional positive relationship between bird diversity and foliage diversity and the inverse relationship found in Patagonia. I propose that particular floristic features of the vegetation rather than structure itself might explain better the diversity of bird species in Patagonian forests.

Three‐dimensional dispersion of drosophilid flies in a cool temperate forest of northern Japan

AbstractThree‐dimensional dispersion of drosophilid flies was studied within a secondary broad‐leaved forest in relation to forest structure. The survey area included the forest margin and old canopy gaps and varied in the foliage height profile from place to place. Using multivariate analyses on the data of drosophilid dispersion, five microhabitats which were different from one another for drosophilids were recognized: (i) canopy layer; (ii) middle layer; (iii) floor layer of forest interior; (iv) upper layer of forest margin; and (v) herbaceous layer of forest margin and gap. The height of living space of canopy species was remarkably lowered at the forest margin. The forest edge was richer in both numbers of individuals and species than the forest interior from the overlap of the grassland and the forest canopy subcommunities and the addition of invaders from other habitats. However, no ‘edge’ species, which were mostly restricted to or spend most of their time in ecotones, were found. It is hypothesized that the above‐ground forest structure consists fundamentally of three zones: (i) the canopy; (ii) the floor; and (iii) the edge. A significant positive correlation was found between the foliage height diversity and the degree of vertical habitat segregation among drosophilid species. The patchiness of vegetation structure influential to the three‐dimensional dispersion in a forest drosophilid community was estimated to be on the scale of 110–450 m2. This scale of subjective habitat patchiness or ‘ecological neighbourhood’ corresponds well with the most prevalent size of canopy gaps occurring in various forests.

Bird communities associated with three traditional agroecosystems in the San Luis Potosi Plateau, Mexico

The bird communities associated with three traditional dry farming systems. their borders and their unfarmed surroundings on the San Luis Potosi Plateau, México, were studied throughout the year. The systems studied were (1) a purely rain-field in a grassland with shrubs, (2) a field on a bajada irrigated with runoff water in a complex and dense community of cacti and shrubs, and (3) a bajio field irrigated with spring moisture and an ephemeral wash in savanna. The results are in agreement with the hypothesis that complex agroecosystems are less susceptible to pest outbreaks than simple ones. There was no typical cropland avifauna; communities depended on the particular type of agroecosystem and on the original habitat. The foliage height diversity index did not always parallel bird richness, since there are factors affecting the latter which did not affect the index. Edge effect was not evident in this study. Although two agroecosystems had lower richness than their surroundings, the presence of isolated fields increased regional bird richness.

Effects of insect herbivory on early plant succession: comparison of an English site and an American site

The effects of insect herbivores on plant community characteristics of early secondary succession were compared in an Old World site (southern Britain) and a New World site (Iowa, U.S.A.). Plant species richness, species diversity, cover abundance, foliage height diversity, and a height index, used as a measure of vegetational structure, were significantly greater at the New World site than at the Old World site. At the Old World site during the first year of succession on bare ground, exclusion of foliar herbivores by the use of non-persistent insecticides significantly increased plant species richness, diversity and the cover abundance of the vegetation. These differences were due to an increase in the annual species in insecticide-treated plots. In the second year the removal of herbivores significantly increased cover abundance due to the enhanced growth of perennial grasses. These results indicate that at the Old World site insect herbivores begin to slow the rate of succession as early as the second year because of their impact on perennial grasses. At the New World site, none of the community characteristics measured were altered by herbivore exclusion. This is due to the relatively small contribution of annuals to species richness and cover abundance during the first year and of perennial grasses to cover abundance during the second year. We suggest that insect herbivores will only affect secondary succession in old fields at the New World site when perennial grasses become abundant, normally three to four years after succession begins.

Relationships between bird community and habitat structure in shelterbelts of Hokkaido, Japan

The relationship between the bird community and habitat structure in wind shelterbelts of Ishikari district was examined.Breeding birds were classified into nesting guilds (hole, canopy, and bush) and also into foraging guilds (outside, canopy, and bush) Both density and species richness in the outside-foraging guild were positively related to forest age variables. On the other hand, bird density in all three nesting guilds and the other two foraging guilds (canopy and bush) was correlated with the vegetation cover of their nesting or foraging sites, and species richness was positively correlated with tree species complexity variables.Bird species diversity (BSD) was closely related to tree species complexity, but not to foliage height diversity (FHD) within woods. However, if woods were re-classified into two groups such as natural and artificial and these were separately analysed, the correlation between BSD and FHD was significant.From these results, it is concluded that both FHD and tree species complexity should be considered together in order to predict BSD within forests. A new index is proposed for this purpose, and its usefulness discussed.

The impact of water buffalo on the monsoon forest ecosystem in Kakadu National Park

AbstractThe intensity of use of forested country in the Kakadu National Park area by feral Asiatic water buffalo can be largely predicted from the area of river floodplain in the vicinity of the site, and tree canopy cover on the site. Thus some areas of monsoon forest appear to have sustained intensive use by buffalo for over a century whereas other areas have probably been little used.With sites exhibiting little buffalo use, mean DBH of trees increased with foliage height diversity (FHD). However, the sites more intensively used by buffalo had a lower canopy and did not exhibit any increase in mean DBH with a pronounced increase in FHD. Other vegetational relationships displayed by the two groups of sites are discussed. Comparison of the monsoon forest sites suggests that compaction of soil by buffalo has caused the death of large trees due to poor recharge of groundwater.The two groups of monsoon forest sites exhibited a wide variety of faunal relationships with FHD. Some species appear to be favoured while others are disadvantaged to various degrees by the habitat changes caused by the buffalo. The most intensively used site appears to have exceeded a threshold in that a number of faunal trends were reversed on that site.The impact of buffalo on some monsoon forest sites is much more fundamental than anticipated. But other sites which appear to be naturally protected by their location have experienced much less change due to buffalo.