Amount Of Leaf Litter Research Articles

Importance of woody vegetation for foraging site selection in the Southern Pied Babbler ( Turdoides bicolor) under two different land use regimes

Intensified land use practices have changed savannas worldwide. Both, heavy grazing-induced shrub encroachment and the decrease in tree density due to woodcutting are assumed to reduce animal diversity. However, most studies in animal ecology have focused on the effects of one of these two land use practices. In our study we analyzed the importance of both shrubs and trees, for foraging site selection of the Southern Pied Babbler ( Turdoides bicolor) in the Southern Kalahari, South Africa for two different grazing regimes: endemic wildlife at Molopo Nature Reserve versus domestic livestock at neighboring farms. We compared vegetation structure at babbler foraging sites with random sites at the microhabitat scale (5×5 m) and the mesohabitat scale (50×50 m), and recorded babbler group size and the amount of leaf litter. Our results show for both scales that mean density of shrubs and trees was higher at foraging sites compared to random sites. We found no differences in foraging site characteristics (i.e. vegetation cover at microhabitat scale and composition and density of woody plant species at both scales) and group size between the two grazing regimes. We conclude that shrub encroachment affects the Southern Pied Babbler positively whereas woodcutting has negative effects.

Riparian forest harvesting and its influence on benthic communities of small streams of sub-boreal British Columbia

Forest harvesting in riparian areas can alter the leaf-litter inputs, shading, and stability of small streams, and many of the details of these impacts are known for coastal streams of the Pacific Northwest. However, little is known about how small streams in the drier, continental areas of western North America respond to logging. We conducted a study of paired stream reaches (comparing one recently harvested (≤3 years) reach and two upstream, forested reaches in each of five streams) in which periphyton, detritus, macroinvertebrate abundance and biomass, and physical features were measured in summer and autumn. In general, recently harvested stream sections tended to be wider and contained more riffle areas than the upstream forested sections. The amounts of leaf litter and algae varied among streams and were not consistently greater or lesser in the forested sections than in the harvested sections. Though the variation in amounts within streams was mainly seasonal, amounts differed more among streams than between pairs of harvested and forested reaches. The communities of benthic invertebrates differed significantly between forested and harvested reaches, but often in opposite directions between streams. The magnitude and direction of differences observed between treatments, streams, or seasons were associated with the specific stream and the method of riparian harvesting used.

계방산 장기생태조사지의 낙엽 생산량 및 낙엽 분해에 따른 양분 동태

본 연구는 온대 북부지역에 속하는 강원도 계방산의 천연 활엽수림에 위치한 장기생태연구(LTER) 조사지를 대상으로 3년 동안 연간 낙엽 낙지 유입량과 낙엽 분해율을 측정하였다. 낙엽낙지량은 채취 시기간에는 통계적으로 유의적인 차이가 있었던 반면, 연도간에는 통계적인 차이가 나타나지 않았다. 3년 간의 전체 연평균 낙엽 낙지량은 6,593 kg <TEX>$ha^{-1}$</TEX> <TEX>$yr^{-1}$</TEX> 이었으며, 그 중 잎이 차지하는 비율은 82.6% 이었다. 수종별 유입량은 본 조사지의 우점종인 신갈나무 잎이 가장 많은 양을 보였으며, 기타수종의 잎, 박달나무 잎, 음나무 잎, 당단풍나무 잎 등의 순이었다. 낙엽 분해율은 층층나무와 당단풍나무, 음나무, 그리고 박달나무 낙엽이 신갈나무 낙엽에 비해 분해 속도가 빨라 1,003일간의 조사 기간 동안 층층나무 낙엽 100%, 당단풍나무 낙엽 96.1 %, 음나무 낙엽 92.8%, 박달나무 낙엽 81.4%, 그리고 신갈나무 낙엽 66.2%가 분해되었다. 신갈나무 낙엽의 분해가 느리게 진행된 것은 다른 수종의 낙엽에 비해 신갈나무 낙엽 내 낮은 양분 함량 같은 기질의 차가 원인인 것으로 나타났다. 칼륨과 마그네슘을 제외한 양분(N, P, Ca) 함량은 분해 초기 함량에 비해 낙엽 분해 과정 동안 증가하였다. 또한 낙엽 분해과정 동안 양분(N, P, K Ca, Mg)의 방출량은 층층나무, 당단풍나무, 음나무 등의 낙엽이 신갈나무 낙엽에 비해 빠른 것으로 나타났다. 이와 같은 결과는 계방산 장기생태조사지 내 우점종의 낙엽 분해와 양분의 동태는 동일한 입지에 있어서도 수종간에 차이가 있음을 나타내는 것이다.시기는 약 6,500 yr BP이후인 것으로 추정된다.균 군집 구조는 <TEX>$CO_2$</TEX> 농도보다는 납 오염 여부에 의해 더 민감하게 특성화됨을 의미한다.로 형태가 유사한 해발 500<TEX>$\sim$</TEX>600 m 구간에서 가장 광범위한 분포를 보였다. 특히 이 구간내 탐방로 상에서 멸종 위기 야생동물 II인 삵(Prionailurus bengalensis)의 배설물이 집중적으로 관찰되어 이에 대한 연구가 연계되어야 할 것으로 사료된다. 선전영화 제작을 위한 영화사를 별도로 설립했다. 1942년부터 1945년 사이에 는 조선총독부의 조종을 받는 한개 영화사만이 존재해 선전영화만을 제작했다.(25.0%), bla<TEX>$_{SHV}$</TEX>, bla<TEX>$_{CTX-M}$</TEX> 두 가지 유전자를 가지고 있는 균주가 10주(27.8%)로 나타나 bla<TEX>$_{CTX-M}$</TEX>을 포함하는 복합유전자가 많이 증가함을 알 수 있었다. 또한 CTX-M형 ESBL을 생성하는 E. coli와 K. pneumoniae에 대한 cefutaxime의 MIC는 256 <TEX>$\mu$</TEX>g/m1 이상으로 ceftazidime의 16-256 <TEX>$\mu$</TEX>g/mL 이상보다 높은 분포를 보였다. 즉, CTX-M형 ESBL 유전자를 지닌 균주에 대한 cefotaxim의 MIC는 ceftazidime의 MIC에 비해서 상대적으로 높은 양상을 보였다. 이러한 결과는 국내의 대학병원 뿐 만 아니라 일반종합병원에서도 CTX-M형 ESBL 생성 E. coli와 K. pneumoniae가 존재하며 확산 중임을 시사한다. 앞으로 CTX-M형 We measured the litterfall quantity and investigated the nutrient dynamics in decomposing litter for three years at the LTER sites installed in a deciduous broadleaf natural forest in Mt. Gyebangsan, South Korea. Litterfall production was significantly different among the sampling dates, whereas it was not significantly different among the years. The total annual mean litterfall production for three years was 6,593 kg <TEX>$ha^{-1}$</TEX> <TEX>$yr^{-1}$</TEX> and leaf litter accounted for 82.6% of the litterfall. The leaf litter quantity was highest in Quercus mongolia, followed by leaf of other species, Betula schmidtii, Kaplopanax pictus, Acer pseudo-sieboldianum, etc., which are dominant tree species in the site. The mass loss from the decomposition of leaf litter was fastest in Cortinus controversa (100%), followed by A. preudo-sieboldianum, K. pictus, and B. schmidtii. 100% of litter for C. controversa, 96.1% for A. pseudo-sieboldianum, 92.8% for K. pictus decomposed, while 66.2% of litter for Q. mongolia decayed for 1,003 days. The lower rate of the mass loss in the litter of Q. mongolia may be attributed to the difference in substrate quality, such as lower nutrient concentrations compared with those of other tree species. The concentrations of N, P, and Ca for five litter types increased over time, while the concentrations of K and Mg decreased over time. Compared with the nutrients in the litter of Q. mongolia, the nutrients (N, P, K, Ca, Mg) in the litter of other species, C. controversa, A. pseudo-sieboldianum, and K. pictus, were released more rapidly. The results showed that the mass loss and the nutrient dynamics in the litter are variable depending on the tree species even in the same site conditions.

The ameliorative effects of pine cultures on forest sites on the island of Rab in Southwest Croatia

The paper investigates the ameliorative properties of pine cultures in their site conditions on the island of Rab. Pines, as allochthonous and pioneer species, were used to afforest degraded and devastated areas on the island because of their important role in the process of progressive vegetation succession. Twelve sample plots were established in the forest pine cultures. They encompassed various pine cultures (maritime pine, Aleppo pine and black pine) in diverse parent substrates (limestone, reddish-brown quartz sand, Flysch) and different soil types (eutric cambisol, cambisol on limestone, red soil and rendzina). To process the data, the following multivariate analyses were used: Two Way Indicator Species Analysis (TWINSPAN), Canonical Correspondence Analysis (CCA) and Indicator Species Analysis. The research results showed differences among the forest cultures of black pine, Aleppo pine and maritime pine. A relationship was found between the quantitative environmental variables (slope, pH, humus, the C/N ratio, age and the quantity of leaf litter) and the vegetation. As well as the relationship of the species towards qualitative variables (type of pine culture, parent substrate, soil type, exposition).

Terrestrial Subsidies of Organic Carbon Support Net Ecosystem Production in Temporary Forest Ponds: Evidence from an Ecosystem Experiment

Recent research suggests that secondary production in aquatic systems can be driven by inputs of energy from terrestrial sources. Temporary forest ponds appear to be unproductive ecosystems that are reliant upon allochthonous inputs of energy to support secondary production, but the functioning of these systems has not been well quantified. To assess the metabolic state of this type of ecosystem as well as to quantify the importance of terrestrial subsidies of carbon to ecosystem function, we conducted an experiment in which we manipulated the amount of leaf litter in ponds. Litter was either removed or removed and replaced (that is, control) from the dry basins of ponds immediately after leaf abscission. Once the ponds filled, we monitored net ecosystem production (NEP) on a biweekly basis from 9 April to 27 May 2002. All ponds were consistently net heterotrophic; however, NEP was significantly less negative in removal ponds. Furthermore, removal ponds also had lower levels of respiration (R) and higher dissolved oxygen levels than control ponds. The removal of litter had no effect on gross primary production, indicating that the difference in NEP between treatments was driven by the change in R. Therefore, it appears that terrestrial inputs of organic carbon support heterotrophic respiration in these ponds, and that the endogenous production of carbon is insufficient to support secondary production.

WHOLE-SYSTEM NUTRIENT ENRICHMENT INCREASES SECONDARY PRODUCTION IN A DETRITUS-BASED ECOSYSTEM

Although the effects of nutrient enrichment on consumer-resource dynamics are relatively well studied in ecosystems based on living plants, little is known about the manner in which enrichment influences the dynamics and productivity of consumers and resources in detritus-based ecosystems. Because nutrients can stimulate loss of carbon at the base of detrital food webs, effects on higher consumers may be fundamentally different than what is expected for living-plant-based food webs in which nutrients typically increase basal carbon. We experimentally enriched a detritus-based headwater stream for two years to examine the effects of nutrient-induced changes at the base of the food web on higher metazoan (predominantly invertebrate) consumers. Our paired-catchment design was aimed at quantifying organic matter and invertebrate dynamics in the enriched stream and an adjacent reference stream for two years prior to enrichment and two years during enrichment. Enrichment had a strong negative effect on standing crop of leaf litter, but no apparent effect on that of fine benthic organic matter. Despite large nutrient-induced reductions in the quantity of leaf litter, invertebrate secondary production during the enrichment was the highest ever reported for headwater streams at this Long Term Ecological Research site and was 1.2-3.3 times higher than predicted based on 15 years of data from these streams. Abundance, biomass, and secondary production of invertebrate consumers increased significantly in response to enrichment, and the response was greater among taxa with larval life spans < or = 1 yr than among those with larval life spans >1 yr. Production of invertebrate predators closely tracked the increased production of their prey. The response of invertebrates was largely habitat-specific with little effect of enrichment on food webs inhabiting bedrock outcrops. Our results demonstrate that positive nutrient-induced changes to food quality likely override negative changes to food quantity for consumers during the initial years of enrichment of detritus-based stream ecosystems. Longer-term enrichment may impact consumers through eventual reductions in the quantity of detritus.

Resource allocation to vegetative and reproductive growth in relation to mast seeding in Fagus crenata

Year-to-year variation in vegetative and reproductive growth was studied in Fagus crenata dominating a forest in Northeast Japan. Trees synchronously produced abundant nuts in 2 mast years during 6 years of study. Nut production was absent or very sparse in the other 4 non-mast years. Annual leaf production estimated from the amount of leaf litter did not differ between mast and non-mast years. Similarly, radial stem growth evaluated from tree ring width was not necessarily reduced in mast years compared with non-mast years. Radial growth decreased only in 1 of the 2 mast years. Trees also invested a substantial amount of nitrogen into reproductive growth in mast years, but mast seeding did not reduce nitrogen investment into the foliage or enhance nitrogen resorption from senescing leaves. We conclude that mast seeding does not place a strong impact on the canopy of F. crenata trees, probably owing to resources stored in perennial tissues.

Phytomass and fire occurrence along forest–savanna transects in the Comoé National Park, Ivory Coast

In tropical West Africa, distribution patterns of forest islands in savannas are influenced by fires which occur regularly in the grass stratum. Along continuous forest-savanna transects in the Comoe National Park, the change in the amount and composition of non-woody phytomass was investigated from savanna to forest interior. This was correlated with the cover of vegetation strata above, soil depth, and the occurrence of seasonal surface fires. Phytomass mainly consisted of leaf litter in the forests (about 400 g m -2 at the end of the rainy season, and about 600 g m -2 at the end of the dry season) and of grasses in the savanna (about 900 g m -2 ). Low grass biomass appeared to be primarily the result of suppression by competing woody species and not of shallow soil. The occurrence of early dry-season fires seemed to be determined mainly by the amount of grass biomass as fuel because fires occurred in almost all savanna plots while forest sites remained unaffected. However, late dry-season fires will encounter higher amounts of leaf litter raising fire probability in forests. Due to the importance of the amount of combustible phytomass, fire probability and intensity might increase with annual precipitation in both savanna and forest.

Coarse woody debris, soil properties and snails (Mollusca: Gastropoda) in European primeval forests of different environmental conditions

We studied the snail fauna of four primeval forests of Central Slovakia and focused on the influence of forest type and coarse woody debris (CWD) on species assemblages. We found a total of 3281 individuals from 39 species. Species assemblages differed between the forests. In SW-facing oak forests, CWD enhanced the proportion of forest species such as the wood-grazing Cochlodina laminata and decreased the proportion of euryecious species like the litter-dwelling Punctum pygmaeum. In NE-facing beech forests, hygrophilous species such as Carychium tridentatum dominated the assemblages. This litter-dwelling snail was especially abundant close to CWD. The NE-facing beech forests harbored more species and individuals than the SW-facing oak forests did. CWD enhanced snail abundance, species richness and biodiversity, irrespective of forest type. We found positive correlations for abundance and species richness to the amount of leaf litter, C org, N tot, Ca 2+, and K +; snail abundance was also positively correlated to soil pH. All these soil chemical factors were higher close to CWD than distant from CWD.

Responses of gastropods to changes in amounts of leaf litter and algae in mangrove forests

Leaf litter, pneumatophores, saplings and patches of macro-algae are common characteristics of habitats in mangrove forests. The amounts of these vary among different parts of mangrove forests. In Port Jackson, some parts of forests under the canopy of trees appeared to have more saplings, longer pneumatophores and greater amounts of leaf litter and macro-algae than did other similarly shaded parts of the forest. The former also appeared to have greater densities of snails, Ophicardelus spp. and Salinator solida, which was confirmed by quantitative sampling. Two field experiments were carried out, in which the amount of litter or algae and the length of the pneumatophores, were manipulated to test six alternative models about influences of these features of habitat that might explain these patterns. In each experiment, both species decreased rapidly in plots with reduced litter and showed no response to the length of the pneumatophores. In the first experiment, there was no response to reductions of algae, but in the second experiment, each species showed a decrease in density when algae were reduced. The implications of these rapid responses to changes in small-scale features of habitat are discussed with respect to managing disturbed habitats.

Spatial structure of litter-dwelling ant distribution in a subtropical dry forest

Understanding the spatial patterns of species distribution is essential to characterize the structure of communities, to optimize species inventories and to evaluate the impact of biotic and abiotic variables. Here we describe the spatial structure of the distribution of leaf litter ant species, and of biotic factors that could explain it, in a subtropical semi-deciduous forest of the Argentinian Chaco, characterized by a dense understorey of shrubs and terrestrial bromeliads. Environmental variables (leaf litter quantity and ground bromeliad density) were measured and ants were collected in 1 m2 quadrats distributed along two 200 m transects at intervals of 1.25 m. Overall 87 species were collected. Sixteen positive associations and a single negative association were observed between the 11 most frequent species taken pair-wise. Our results suggest that the spatial distribution of leaf litter ants was determined at two different scales. At a small scale (period below 10 m) a periodic spatial structure, likely due to intraspecific competition, produced a succession of peaks of abundance separated by gaps. At a larger scale (period around 50 m), periodically distributed environmental factors induced aggregates of colonies of species responding positively to these factors. A high quantity of leaf litter and, to a lesser extent, a high density of ground bromeliads promoted a high density and a high species richness of ants. Numerically dominant ants being generally positively associated, interspecific competition was apparently weak. All ant species whose abundance was correlated with an environmental factor were not completely spatially structured by it. This suggests that some other factors, such as intraspecific competition, may have counter-effects.

Contrasting response of stream detritivores to long-term nutrient enrichment

We examined growth and production responses of two dominant stream detritivores (chironomids and Tallaperla spp. stoneflies) at opposite ends of the ‘‘slow-fast’’ life-history continuum and with distinct feeding characteristics (i.e., consumption of fine particulate organic matter vs. leaf litter) to a 2-yr experimental nutrient enrichment of a headwater stream. Enrichment had large positive effects (;50% increase) on chironomid growth rates but no effects on those of Tallaperla spp. On an areal basis, enrichment had a large positive effect on chironomid production (;183% increase) but no detectable effect on the production of Tallaperla spp. When production data were examined on a per gram food basis, enrichment had an apparent positive effect on the production of both chironomids and Tallaperla spp. Together, these results suggest that nutrient-induced changes to organic matter quality had consistent and substantial positive effects on short-lived chironomids, but effects were limited for longer-lived stoneflies. The lack of a system-wide effect on Tallaperla spp. may have been due to nutrient-induced reductions in leaf litter quantity, despite increases in litter quality. Our results indicate that species-specific characteristics such as life span and dominant food type may be important in determining population- and community-level responses of consumers to nutrient enrichment of detritus-based aquatic ecosystems.

Effects of goat pastoralism on ecosystem carbon storage in semiarid thicket, Eastern Cape, South Africa

Abstract Intensive pastoralism with goats transforms semiarid thicket in the Eastern Cape, South Africa from a dense vegetation of tall shrubs to an open landscape dominated by ephemeral grasses and forbs. Approx. 800 000 ha of thicket (which prior to the introduction of goats had a closed canopy and a Portulacaria afra Jacq. component) have been transformed in this manner. Ecosystem C storage in intact thicket and loss of C due to transformation were quantified. Carbon storage in intact thicket was surprisingly high for a semiarid region, with an average of 76 t C ha−1 in living biomass and surface litter and 133 t C ha−1 in soils to a depth of 30 cm. Exceptional C accumulation in thicket may be a result of P. afra dominance. This succulent shrub switches between C3 and CAM photosynthesis, produces large quantities of leaf litter (approx. 450 g m−2 year−1) and shades the soil densely. Transformed thicket had approx. 35% less soil C to a depth of 10 cm and approx. 75% less biomass C than intact thicket. Restoration of transformed thicket landscapes could consequently recoup more than 80 t C ha−1.

Litter flux in Kuala Selangor Nature Park mangrove forest, Malaysia

The amount of litter production, litter standing crop and export of leaf litter were studied in Kuala Selangor Nature Park mangrove forest, Malaysia. The rates of leaf fall, small branches, bracts, flowers, propagules and total litter varied from 1.63-3.07 g/m2/day, 0.08-0.38 g/m2/day, 0.13-0.39 g/m2/day, 0.01-0.23 g/m2/day, 0.03-2.29 g/m2/day and 2.31-4.46 g/m2/day respectively. Comparatively higher rate of total litter fall was observed during the drier months of July 02, July 03 and August 02; and propagules contributed 31.00 to 52.00% of the total litter fall during the dry season. Relatively higher rate of leaf litter production was observed during February 02 followed by March 03 (intermediate seasons). The rate of total litter production and leaf fall showed significant (F, p&lt;0.05) negative correlations with rainfall and relative humidity while positive correlations were observed with temperature. The amount of small litter standing crop at different seasons varies from 63.45 to 104.59 g/m2 and comparatively higher amount of leaf litter and bract was recorded during the intermediate seasons while relatively higher amount of propagules was observed during the dry season. The export of leaf litter varied from 19.46 to 50.00 % of total leaf fall during the wet and dry months respectively.

Above- and below-ground litter production in three tropical montane forests in southern Ecuador

Litter production from above-ground (leaves, twigs, fruits, flowers) and below-ground (roots) plant organs is an important component of the cycling of carbon and nutrients in forests. Tropical montane forests possess comparatively large quantities of fine-root biomass, suggesting that litter production by dying fine roots may represent a major component of total litter production. In a comparative study in three tropical montane forests of southern Ecuador at 1890, 2380 and 3060 m elevation, we measured leaf-fall by litter trapping and fine-root litter production by sequential soil coring and fine-root biomass and necromass analysis for about 1 y with the objectives (1) to quantify annual above- and below-ground litter production, and (2) to investigate elevational differences in litter production. Leaf litter mass decreased to less than a third (862 to 263 g m−2 y−1) with increasing elevation (1890 m to 3060 m), whereas fine-root litter production increased by a factor of about four (506 to 2084 g m−2 y−1). Thus, the ratio of leaf to fine-root litter shifted by an order of magnitude in favour of fine-root litter production between 1890 to 3060 m. Fine-root litter production was not synchronized with leaf litterfall and was seasonal only at 3060 m with mortality peaks in the drier and the wetter periods. We conclude that dying fine roots represent a very important fraction of total litterfall in tropical montane forests that can exceed the quantity of leaf litter. At 3060 m, the largest part of the organic material on top of the soil must originate from dying fine roots but not from fallen leaves.

Distribution pattern of woodlice (Isopoda) and millipedes (Diplopoda) in four primeval forests of the Western Carpathians (Central Slovakia)

We collected 1605 isopod individuals (eight species) and 671 diplopod individuals (17 species) in four primeval forests of the Western Carpathians, Central Slovakia, by leaf litter extraction. The forests are of different temperate deciduous forest types varying in tree species, aspect, elevation and soil characteristics. The oak forests, established on southwest oriented slopes at an elevation of 280–600 m, were characterized by Hyloniscus riparius, Porcellium conspersum, Enantiulus nanus and Ophioiulus pilosus. The beech forests, established on northeast oriented slopes at an elevation of 700–1100 m, were characterised by Ligidium hypnorum, Trachysphaera costata and Polyzonium germanicum. A remarkable increase of the total number of species and individuals occurred in both forest types adjacent to coarse woody debris (CWD). Woodlice density close to CWD was between 200 and 630 individuals m −2 (35–130 individuals m −2 distant from CWD); millipede density close to CWD ranged from 60 to 230 individuals m −2 (15–75 individuals m −2 distant from CWD). Species richness of both taxa close to CWD varied from 13 to 16 species m −2 (7–12 species m −2 distant from CWD). Thus, CWD has a significant influence on saprophages. However, structural components such as CWD and the amount of leaf litter did not significantly alter species assemblages. Species at sites distant from CWD were a subset of species at sites close to CWD. According to a canonical correspondence analysis (CCA), ‘forest type’ and ‘elevation within a slope’, as well as chemistry of the upper soil layer, i.e. ‘acidification’ and ‘nutrition’, strongly influenced species assemblages.

Survivorship ofAnopheles gambiaesensu stricto (Diptera: Culicidae) Larvae in Western Kenya Highland Forest

The western Kenya highland has been experiencing dramatic landuse changes in the past three decades. Landuse change has been hypothesized to be one of the mechanisms for malaria epidemics in African highlands because it can alter the physical and chemical characteristics of mosquito breeding habitats. One important landuse change in western Kenya highland is deforestation. The current study examined the effects of forestation or deforestation on the survivorship of Anopheles gambiae larvae and colonization of other aquatic insects in larval habitats in Kakamega forest (elevation 1,500-1,700 m above sea level), western Kenya. We found that the survivorship of An. gambiae larvae was reduced from 55 to 57% in habitats fully exposed to sunlight (open habitats) to 1-2% in habitats with full forest canopy coverage (forest habitats) and partial canopy coverage (forest edge habitats) in two out of three trials. The average daily water temperature of the open habitats was approximately 3-3.4 degrees C higher than the forest habitats. Insect species in the orders of Diptera, Coleoptera, and Odonata colonized the larval habitats, but the three habitat types differed greatly in the animal assemblage. Canonical correspondence analysis found that water temperature and amount of leaf litter were the significant variables associated with animal assemblages. Redundancy analysis revealed that openness and the presence of predatory animals were significantly related to An. gambiae survivorship. This result suggests that deforestation facilitates the survival of the immature stage of An. gambiae in the highland.

Effects of pasture development on the ecological functions of riparian forests in Hokkaido in northern Japan

In the summer, the forest canopy lowers the water temperature, which is very important for anadromous fish, and its population density is significantly lower in grassland streams. Leaf litter and terrestrial invertebrates are the critical food resources for stream organisms. In a basin where the riparian forest is preserved, but other areas have been cut, the amount of leaf litter is almost equivalent to that in an intact natural basin. The annual input of terrestrial invertebrates falling into the forested reaches was 1.7 times greater than that in the grassland reaches, and fish biomass was significantly less in the grassland reaches. In-stream large woody debris creates storage sites for organic and inorganic matter and enhances habitat diversity for aquatic biota. However, the volume and number of large wood pieces decreased significantly with pasture development, because it clears the riparian forests and covers the riverbanks with grass. Fine sediment is a prominent by-product of agricultural development and adversely impacts periphyton productivity, the density and diversity of aquatic invertebrates, fish feeding, fish spawning and egg survival. We also examine the adequate width of a riparian buffer if it is to be able to satisfy its ecological functions.

Effects of habitat complexity on forest beetle diversity: do functional groups respond consistently?

ABSTRACTWe examined the responses of a beetle assemblage to habitat complexity differences within a single habitat type, Sydney sandstone ridgetop woodland, using pitfall and flight‐intercept trapping. Six habitat characters (tree canopy cover, shrub canopy cover, ground herb cover, soil moisture, amount of leaf litter, and amount of logs, rocks and debris) were scored between 0 and 3 using ordinal scales to reflect habitat complexity at survey sites. Pitfall trapped beetles were more species rich and of different composition in high complexity sites, compared with low complexity sites. Species from the Staphylinidae (Aleocharinae sp. 1 and sp. 2), Carabidae (Pamborus alternans Latreille), Corticariidae (Cartodere Thomson sp. 1) and Anobiidae (Mysticephala Ford sp. 1) were most clearly responsible for the compositional differences, preferring high complexity habitat. Affinities between general functional groupings of pitfall‐trapped beetles and habitat variables were not clear at a low taxonomic resolution (family level). The composition and species richness of flight‐intercept‐trapped beetles were similar in high and low complexity sites. Our study demonstrates that discrete responses of the various functional groups of beetles are strongly associated with their feeding habits, indicated by differing habitat components from within overall composite habitat complexity measures. Although habitat preferences by beetle species may often reflect their foraging habits, clarification of the causal mechanisms underpinning the relationships between habitat complexity and beetles are critical for the development of general principles linking habitat, functional roles and diversity.

Litterfall of a subtropical evergreen broad-leaved forest in Okinawa island, Japan

The seasonal patterns of litterfalls, such as leaves, woody organs, reproductive parts, insect bodies, and feces, were investigated monthly for three years from January 1999 to December 2001 in a subtropical evergreen broad-leaved forest in the northern part of Okinawa Island, Japan. The total annual litterfall was estimated at 6.66-8.28 Mg ha-1 yr-1. The litterfall was mainly composed of leaves (52.4- 54.8% of the total litterfall), about half of which were from Castanopsis Sieboldii. The species composition of leaf litter was almost consistently the same every month for a year. The leaf litter was separated into two groups: one group, which had a high proportion of the total leaf litter, included C. Sieboldii, Schima Wallichii, Elaeocarpus japonicus, and Cinnamomum Doederleinii; the other group included the other 44 species. The species diversity indexes of leaf litter H’ and J’ showed their minimum values in March, when the leaf litter reached its maximum. There was no significant difference in species rank among years in terms of the annual amount of leaf litter. The mean leaf litter per tree of a given species was significantly proportional to its corresponding basal area, regardless of species and year. The degree of overlap in the seasonal patterns of litterfall components showed that leaves, insect bodies, and reproductive parts are nearly overlapped, but woody organs and feces are more or less exclusive to the other three components. Although the seasonal patterns in leaf litter of C. Sieboldii, S. Wallichii, and E. japonicus were nearly overlapped, the seasonal pattern in leaf litter of C. Doederleinii was almost independent of those of the other three species.