Showing papers on "Undergrowth published in 2006"

Changes in bird communities following conversion of lowland forest to oil palm and rubber plantations in southern Thailand

Abstract: This paper describes changes in bird communities following the conversion of lowland forest to commercial oil palm and rubber plantations. Conversion of forest to plantations resulted in a reduction in species richness of at least 60%, with insectivores and frugivores suffering greater losses than more omnivorous species. Of the 128 species recorded across all habitats, 84% were recorded in forest, and 60% were recorded only in that habitat. Of the 16 Globally Threatened or Near-Threatened species recorded in the study, 15 were recorded only in forest. Species occurring in plantations were significantly more widespread in Thailand than species recorded only in forests and had a tendency towards smaller body size. Species richness in plantations was unaffected by plantation age or distance from nearest forest edge, but was significantly greater where undergrowth was allowed to regenerate beneath the crop trees. Bird communities in oil palm and rubber plantations were extremely similar, and there was a strong positive correlation across species in their relative abundance in each plantation type. The results indicate that a high proportion of species formerly present in the region are unable to adapt to conversion of forest to oil palm and rubber plantations, resulting in large losses of bird species and family richness and the replacement of species with restricted ranges and high conservation status by those with extensive ranges and low conservation status. Initiatives that reduce pressure to clear new land for plantations, for example by increasing productivity in existing plantations and improving protected area networks, are likely to be more effective in conserving threatened forest birds than initiatives to improve conditions within plantations, though both should be encouraged.

Berenty Reserve: A Research Site in Southern Madagascar

Abstract: The forest reserves of Berenty Estate were established by the de Heaulme family in consultation with local Tandroy clans, beginning in 1936 when the de Heaulmes founded a sisal plantation beside the Mandrare River (Jolly, 2004). Some 5000 ha of spiny forest were felled, but 1000 ha remain as original forest reserves. The reserves comprise several different parcels, including a spiny forest parcel called Rapily and two large areas of gallery forest, Bealoka (100 ha) and the main Berenty Reserve (200 ha). These two gallery forest reserves were natural “islands” of extremely rich habitat formed by ancient oxbow lakes or an entire river arm. The forests are dominated by Tamarindus indica, the tamarind tree (Figures 3.1 and 3.2). Berenty has the semiarid climate of Madagascar’s southern domain. Only along rivers with their high water tables can tamarind forest survive; elsewhere, there is the surreal succulent vegetation of Madagascar’s spiny forest. (Figure 3.3). Originally, the gallery forest was divided from the spiny forest by the steep banks of the old riverbed, easily traversed by lemurs, but with sharply different vegetation at top and bottom of the bank. Now the reserves are almost wholly isolated by sisal fields. The “islands” of gallery forest might seem too small to matter for conservation, but two overflights of the Mandrare Valley in 2004 showed that they are the only gallery forests remaining below the headwaters, except for two much smaller sacred forests near Ifotaka and a tract of tamarinds across the Mandrare River from Berenty that has little undergrowth and sparse canopy (Jolly, pers. obs.). Elsewhere there are isolated tamarind trees but no actual blocks of this forest type. Southern gallery forests are clearly one of the most threatened forest types of Madagascar (see Sussman et al., this volume).

Movement trajectories and habitat partitioning of small mammals in logged and unlogged rain forests on Borneo.

Abstract: Summary 1 Non-volant animals in tropical rain forests differ in their ability to exploit the habitat above the forest floor and also in their response to habitat variability. It is predicted that specific movement trajectories are determined both by intrinsic factors such as ecological specialization, morphology and body size and by structural features of the surrounding habitat such as undergrowth and availability of supportive structures. 2 We applied spool-and-line tracking in order to describe movement trajectories and habitat segregation of eight species of small mammals from an assemblage of Muridae, Tupaiidae and Sciuridae in the rain forest of Borneo where we followed a total of 13 525 m path. We also analysed specific changes in the movement patterns of the small mammals in relation to habitat stratification between logged and unlogged forests. Variables related to climbing activity of the tracked species as well as the supportive structures of the vegetation and undergrowth density were measured along their tracks. 3 Movement patterns of the small mammals differed significantly between species. Most similarities were found in congeneric species that converged strongly in body size and morphology. All species were affected in their movement patterns by the altered forest structure in logged forests with most differences found in Leopoldamys sabanus. However, the large proportions of short step lengths found in all species for both forest types and similar path tortuosity suggest that the main movement strategies of the small mammals were not influenced by logging but comprised generally a response to the heterogeneous habitat as opposed to random movement strategies predicted for homogeneous environments. 4 Overall shifts in microhabitat use showed no coherent trend among species. Multivariate (principal component) analysis revealed contrasting trends for convergent species, in particular for Maxomys rajah and M. surifer as well as for Tupaia longipes and T. tana, suggesting that each species was uniquely affected in its movement trajectories by a multiple set of environmental and intrinsic features.

Population structure of a threatened plant, Pulsatilla patens, in boreal forests: modelling relationships to overgrowth and site closure

Abstract: Pulsatilla patens (L.) Mill. (Ranunculaceae) is a threatened plant which in Fennoscandia favours south-facing, warm slopes of pine-dominated esker forests. The cessation of cattle grazing, modern forestry practices, and especially efficient fire prevention have resulted in closure of undergrowth vegetation in these forests. Using generalized linear models (GLM), we studied the relationships between habitat factors (covers of field and ground layer and amount of litter) and the population structure of P. patens in 48 populations in Finland in order to identify favourable conditions for regeneration. The largest populations occurred at sites with intermediate values of both ground and field layer. The number of juvenile plants was also highest at intermediate values of ground layer. Dense moss layer and abundant litter had a negative effect on the flowering of P. patens. In conclusion, creation and maintenance of habitat heterogeneity to prevent the closure of undergrowth vegetation is of paramount importance for the successful reproduction of P. patens.

Nest-site selection and predation in Savi’s Warblers, Locustella luscinioides.

Abstract: Capsule: Savi’s Warblers preferred sites dominated by high and dense Juncus and Rubus with thick litter, and avoided pure reeds; predation was higher in sites with less litter. Aim: To describe nest-site selection and identify which habitat and nest features influence predation risk. Methods: Comparisons were made between habitat characteristics measured at nest-sites and random points, and between predated and successful nests. Results: Total vegetation cover, litter thickness, habitat type, undergrowth height and undergrowth cover, which were higher or denser at nest-sites, were the most important variables influencing the distribution of Savi’s Warbler nests. Nests were most often predated in sites with low litter thickness. Conclusion: Savi’s Warblers are dependent on the presence of dense low vegetation and litter for nesting, which should be maintained close to or within reed-beds for their benefit. (Less)

Study on the biomass structure and distribution of natural secondary forest of Pinus massoniana

Abstract: The study on the structure and distribution character of biomass of a 46-year-old natural secondary forest of Pinus massoniana in Chongqing and its productivity shows,that the primary productivity of the forest ecosystem is 834 t/(hm~2·a)The biomass is 14608 t/hm~(2),the distributing sequence of the biomass of the forest ecosystem is: tree stratum(8743%)humus layer(565%)undergrowth(546%)herb(146%)The biomass of the tree layer is 12772 t/hm~(2) and biomass distributing sequence of different organs is: trunk(7282%)branch(1119%)root(927%)bark(443%)needle(229%)Regarding the vertical structure of biomass of each type of organ,the biomass of trunks under the height of 10m accounts to 8113% of its total;the biomass of branches between 12 m and l6m accounts to 8225% of its total;the biomass of one-year-old needles between 12 m and 18m accounts to 9325% of its total;and the biomass of roots in the soil layer of 0-40 cm accounts to 7645%The present stage productivity of the community is lower and its structure is irrationalThe forest-type of the forest community and productivity structure of tree layer should be regulated so as to improve the integrate effects of the community

Impacts of Rapid Urbanization on Carbon Fixing and Oxygen Production of Vegetation in the Pearl River Delta

Abstract: The Pearl River Delta which has an area of 4.17 ×10~4 km~2 and a population of 4078.06×10~4 is a typical urbanizing area in China.There are 28 cites and 434 towns and the mean distance between the towns is less than 10 km.The Pearl River Delta has been the most rapidly urbanizing area in China and the world for the last 20 years.Urbanization is an important factor for land use change, which has an impact on the eco-environment due to vegetation destruction etc.However,very few studies focus on the impact of land use change on the eco-environment by estimating the loss of biomass and net primary production(NPP) of vegetation due to rapid urbanization.The loss of NPP has implications for carbon fixing and oxygen production.The tree biomass of forest was estimated from tree trunk volume.The biomass of undergrowth in forests was estimated based upon a case study of the Liuxihe forests of Guangzhou.The NPP of forest is related to biomass,condition and age of forest.Therefore,the NPP of forest was estimated by formulae relating NPP and biomass.The biomass and NPP of shrubland,sparse woodland,orchard and pasture were estimated by their mean values for the region. The biomass of a given crop was calculated by economic production and a relative economic coefficient.The NPP of all crops was estimated from biomass times multiple crop indices.Carbon content is calculated from biomass using a factor of 0.45.Land use has been changed with rapid urbanization in the Pearl River Delta.The area of cultivated land has decreased and the area of residential and industrial land has increased.Woodland,pasture and unused land has also decreased, and area of transport infrastructure,orchard and water bodies increased.The area of cultivated land,sparse woodland shrubland,and pasture decreased by 304 578 hm~2,77 093 hm~2 and 604 hm~2 respectively from 1990 to 2000,because large amounts of ecological land were used for urban expansion in the Pearl River Delta.The 'lost' areas of cultivated land,sparse woodland shrubland,and pasture in 10 the year period were equal to 28.78%,30.15% and 38.57% respectively of those in 1990.The regional vegetation area was decreased by 8.00%.The ability for a balance of carbon and oxygen for the ecosystem of the Pearl River Delta was decreased by 8.68%.The amount of CO_2 fixed and O_2 production decreased by 4 000 137 t/a and 2 909 200t/a respectively.Dongguan was one of the most rapidly urbanizing cities.Its area of residential industrial land and transport infrastructure increased by 1.12 times and 1.4 times respectively in 10 years.Vegetation area in Dongguan was decreased by 25.35%,of which cultivated land,orchard,forest, sparse woodland and shrubland,and pasture decreased by 21370 hm~2,13214 hm~2,6979 hm~2,473 hm~2 and 41 hm~2 respectively.The biomass and NPP of Dongguan decreased by 1213961 t and 471419 t/a,respectively.The biomass and NPP of various vegetation types declined.The biomass and NPP of cultivated land,orchard,forest,sparse woodland and shrubland,and pasture decreased by 143 820,313 172,747 213, 9 346,410 and 249 815 t/a,121 569,94 573,5 150,312 t/a,respectively.Carbon fixing and oxygen production of vegetation were decreased by 26.76%.It was shown that the ability of vegetation to fix carbon and produce oxygen would be reduced by 2/3 if the suburban area had been changed to an urban area according to a case study in urban Guangzhou.The study indicates that the impacts of land use change on the eco-environment cannot be neglected or ignored.

Dynamics of Undergrowth and Its Application to Vegetation Control of Planted Chamaecyparis obtusa Endl. Forests with Special Reference to Mitigation of Surface Soil Loss.

Abstract: 林分密度管理をヒノキ人工林における土壌保全目的での下層植生管理に応用するために, 高知県下のヒノキ人工林に28の調査プロットを設け, 下層植生に対する強度間伐の影響と, 通常の管理下での下層植生の動態を調べた。強度間伐試験地では設定後2～3年間の収量比数 (Ry) の推移と2～3年後の植被率を調べた。通常施業試験地では設定時を0年次として, 0, 5, 10～13年次のRyと植被率を調べた。その際, 調査プロットの海抜高 (温量指数) に基づいて三つの温度域 (ウラジロ・コシダ域, カシ域, 落葉樹域) を区別し, 植被率を6段階評価した被度指数を土壌侵食抑制効果と光要求度の異なる六つの生活型 (ウラジロ・コシダ, 陽性草本, 林床草本・地表植物, 常緑木本, 落葉木本, ササ) のおのおのについて別個に求めた。強度間伐が被度指数に及ぼす影響は生活型によって異なった。また, 同じ生活型でも温度域によって異なる反応を示すものがあった。通常施業試験地では調査期間を前期 (0→5年次) と後期 (5→10～13年次) に分け, 期間ごとに求めた各生活型の被度指数の期間変化量 (dC) とRyの期間累積偏差 (ΣdRy×100) との関係を調べた。両者の関係には生活型間での差や, 温度域間での差が認められた。また, 生活型別の被度指数の合計値が40未満の林分 (貧植生型林分) と40以上の林分を区別すると, dC とΣdRy×100との関係が両林分間で異なっていた。以上の結果に基づいて, 生活型, 温度域, 貧植生型林分か否か, を区別してRy-植被率関係のデータを集積することにより, 下層植生管理を目的とした密度管理モデルの実用性が高められることを指摘した。

Study on Biodiversity of the Tropical Rubber Plantation in Hainan

Abstract: The types of vegetation and the changes of the biodiversity were studied by investigating the species diversity of rubber forest in different age class There are 207 species of vascular plants which belong to 113 genera and 61 families The dominant species is shade-enduring family Gramineae The typical vegetation communities of undergrowth were defined by vegetation analyses: (1) Association Juvenile Sun-Shrub (2) Association Eupatorium odoratum (3) Association Imperata cylindraca (4) Association shade-enduring Gramineae (5) Association Piper sarmentosum Roxb (6) Association Dicranopteris pedata (7) Association Pteridophyta (8) Association Sun-Gramineae The biodiversity in rubber forest was different due to the rainfall, the soil nutrient content and the age of the rubber forest The more plentiful the rainfall was, the more abundant the biodiversity was The biodiversity showed that there was a declining trend with the increase of rubber forest's age A co-relationship between plant diversity and soil nutrient content was studied with plant community species diverse index The biodiversity has a remarkable positive relation with soil organic matter, total N content, and unremarkable relation with soil P(total phosphorus, effective phosphorus) and K(total potassium and effective potassium) content

The Psychotria vogeliana-community in the spontaneous undergrowth of teak (Tectona grandis L. f.) plantations in south-Benin: ecological and sllvicultural indicatory values

Abstract: The spontaneous undergrowth of teak (Tectona grandis L. f.) plantation in Djigbe forest (south Benin) has been studied. The Psychotria vogeliana-community is identified from ten representative phytosociological releves. This community is an indicator of sandy plateau soils generally associated with the least productive plantations. It's composed of 91 species with a mean of 32 species per releve. The study of distribution spectra reveals the abundance of phanerophytes, secondary forest species and phytogeographically widespread species; they represent respectively 86%, 48% and 50% of the total number of species. The analysis of species diversity indicates that the Psychotria vogeliana-community is somewhat diversified, but the species abundance is weakly balanced (2.1 for Shannon-Wiever index and 0.48 for evenness index).

Winter bird distribution in abiotic and habitat structural gradients: A case study with

Abstract: The influence of habitat structure and abiotic factors on winter bird distribution was studied at the within-habitat level in the montane Pyrenean oakwoods of central Spain. Abiotic factors associated with thermal stress were estimated based on altitude and solar radiation received by woodlands (calculated by the steepness and orientation of the terrain). This paper demonstrates the great importance of abiotic factors in influencing bird distribution. Several bird community parameters related to density and species richness decreased with altitude, while they increased with radiation incidence of oakwood plots (i.e., birds avoided northern orientations where solar radiation is minimal in winter). The most important habitat structure variables related to bird distribution were the density of young and mature oaks. A thick undergrowth of thin oaks negatively influenced total bird abundance and species richness and the number of species of the ground searchers guild. Conversely, oak maturity played a positive role on total bird density and species richness and on the number of species of tree canopy gleaners and trunk foragers. Bird density and species richness were better explained by tree regression models considering complex interactions between variables than by general linear regression analyses. To enhance winter survival and habitat suitability for birds, forest management in these mediterranean endemic oakwoods should preserve the most mature forests at lower altitudes exposed to the south.

Characteristics of Alnus cremastogyne plantation community and its biomass in central Yunnan Plateau

Abstract: A study of the Alnus cremastogyne plantation showed that it was characterized by fast-growing , flourishing root system , quick undergrowth restoration , higher biodiversity , soil improving and water holding capacity .The biomass of tree organs were in order trunk root branch bark leaf .The roots in the soil layer of 0 -40cm accounted for 96.14 %of the total roots .The biomass in the arbor layerwas the largest , accounting for 84.93 % of the total biomass of the plantation .The biomass of leaf litter layer , herbage layer and shrub layer were less than the arbor layer .Finally regression models of the biomass of different Alnus cremastogyne organs were established to provide the reference for the management of the Alnus cremastogyne plantation . [ Ch , 5 tab .16 ref .]

Growing a burning program: challenges and oportunities

Abstract: But frequent forest burning did more than reduce the undergrowth and improve the habitat for preferred species. In many cases it created grasslands in areas where forest otherwise would have existed. Prairies extended into Ohio, western Pennsylvania, and western New York. In Virginia, the Shenandoah Valley—a broad valley located between the Blue Ridge Mountains and the Allegheny’s—was on vast grass prairie that covered more than 1,000 square miles. Native Americans burned the area annually. R.C. Anderson wrote that the eastern prairies and grasslands “would mostly have disappeared if it had not been for the nearly annual burning of these grasslands by the North American Indians.” In the West, as well, Indian burning greatly extended the area of grasslands and reduced the area of forest.

La reproduction du roitelet à triple bandeau Regulus ignicapillus dans une chênaie caducifoliée de l'Allier (France)

Abstract: Firecrest are found yearly in mature deciduous oak Quercus robur and petraea timber forest of the Allier departement, numbers are variable but densities never exceed 2 territorial males per 10 ha. From 2002 to 2005, on 9 plots located in Lespinasse state forest the species used the same areas, always including trees colonized by ivy Hedera helix. Nests are generally hidden in ivy covering a trunk (62% of cases) or main branches (20% of cases) of canopy oaks, more rarely in Hornbeam Carpinus betulus and Field Maple Acer campestre of the lower canopy. Nests are found from 2.5 to 22 m from the ground (mean 9.6m, n=32). Most nest face north (52%) or east (27%), and are therefore in the shade for most of the day. Territorial and singing behaviour of males is described, especially during times without a mate and incubation. In 2002, 2004 and 2005 almost half the sites were used by males that remained single, some of them remaining territorial for up to 2-4 consecutive months. In 2003 all males found a mate. As no nests were inspected clutch size is not known, but the monitoring of 23 pairs over three years proves that 16 did not raise a single fledged juvenile. The seven successful first broods led to three second brood attempts. The total number of emancipated juveniles reared by a pair through all its breeding attempts varies from 2 to 6. Amongst the 10 breeding individuals (7 males and 3 females) colour-ringed in 2003, only one male, which had successfully completed both its breeding attempts, attempted unsuccessfully to breed in 2004 with a new female after having overwintered on site. This male was still present until early April 2005. A second male, also overtering in its breeding territory disappeared before the following breeding season. Overwintering of the species is facilitated on plots with a lot of Holy ilex aquifolium in the undergrowth which is used a lot by the species and Goldcrest which only overwinters on site.

Studies on the Species Diversity in Undergrowth Vegetation of Artificial P.elliottii Forest Communities

Abstract: The characteristics of species diversity of different types of artificial P.elliottii forest communities were studied. The results were as follows: Firstly,the species such as Symplocos baniculata,Smilax china,Rubus corohorifolius,Vitex negundo L.,Rosa cymosa etc had a comparable higher IV(important value index) in every community type.Secondly,the richness index of shrub layer species of different community types ranged from 3 to 28,and the evenness index from 0.629 0 to 0.954 7;the Simpson index from 0.606 5 to(0.933 8),the Shannon-Wiener index from 1.459 2 to 3.980 9.Thirdly,The species richness index and Shannon-Wiener index of type Ⅲ were significantly lower than those of the other two types,but the Simpson index order was typeⅠtype Ⅲ typeⅡand the evenness index order was type Ⅲ typeⅠ typeⅡ.Fourthly,for type Ⅲ,suitable measures should be taken,incldding introducing endurable species,such as,Symplocos baniculata,Smilax china,Gardenia jasminoides.etc.to improve the recovery course of undergrowth(vegetation).

A Study on Species Diversity in Undergrowth Vegetation of Four Plantations at Yulin,Guangxi

Abstract: An investigation was conducted on the species diversity of different plantations(including:Pinus massoniana,Cunninghamia lanceolata,Eucalyptus grandis×Eucalyptus urophylla,and Castanopsis hystrix plantations) in Dayi Forest Farm,Yulin City of Guangxi.The results were as follows:(1)The plant species of the plantations were rich,there were 54~62 species in community(average was 58±3.36),39~51 species in shrub layer(average was 45±4.97) and 11~15 species in herb layer(average was 13±2.31).(2)The variation of Shannon-Wiener index among plantations was 0.6915~2.9972 in community,2.7985~3.3037 in shrub layer,0.2626~1.8930 in herb layer.Eucalyptus grandis ×Eucalyptus urophylla plantation had the biggest Shannon-Wiener index and Pinus massoniana plantation had the smallest index.The variation of evenness index among plantations was from 0.1710 to 0.7318 and similar to Shannon-Wiener index.(3)The plantations were high in similarity,and the species numbers in the two plantations mentioned above were from 37.78% to 53.78%.(4)The plant species diversity of plantations depended on environmental condition,structure of stand and disturbance,and had nothing to do with the tree species of plantation.