Slow death of Atlantic forest trees in cocoa agroforestry in southeastern Brazil

Cocoa (Theobroma cacao) is cultivated in the states of Bahia and Espírito Santo in eastern Brazil under the so-called cabruca system, where the understorey of native Atlantic forest is cleared and the canopy is thinned out to provide adequate shading for the cocoa trees. Apart from its economic and social role, the cabruca system is said to be important for the conservation of Atlantic forest biodiversity. In this paper we studied tree species richness and forest structure of cabrucas to examine the demographic health of these forests and discuss their long-term survival. Data were collected in 20 farms located alongside a 30km track of the northern margin of the Rio Doce, in northern Espírito Santo. All trees 5cm DBH were identified and their diameter was measured in 80 plots (600m²), totalling 4.8ha of sampled area. Recorded trees were also allocated to four different regeneration phases (pioneers, early secondary, late secondary and climax). The inventory resulted in 507 trees belonging to 105 species in 39 families. This species richness is much lower than in less disturbed forests located in the region. Pioneers and early secondary species dominate the cabruca forest in terms of number of species (56.2%), density (71.0%) and basal area (72.3%). The distribution of diameter frequency showed an imbalance in tree regeneration. Most trees in the range of 5–30cm DBH were pioneers (40.7%), or early secondary species (32.6%), while late secondary and climax trees were less frequent (10.2 and 16.5% of the sampled trees, respectively). The dominance of species of early regeneration phases was also observed for trees >30cm DBH (69.0% of pioneers or early secondary and 31.0% of late secondary or climax species). The results indicated that the cabruca forests are not only less diverse and less dense than secondary or primary forests of the region, but also, and more importantly, their natural succession and gap dynamics are being severely impaired. As a consequence, cabrucas present a structure where tree species of late successional phases are becoming increasingly rare while pioneers and early secondary species are becoming dominant. If current management practices of thinning and clearing of native trees are not improved, the long-term survival of these forests is questionable and their role in maintaining biodiversity in the long run is limited.     

EDTA-assisted heavy-metal uptake by poplar and sunflower grown at a long-term sewage-sludge farm

Little information is available concerning the efficacy of chelates applied to biosolids (sewage-sludge)-treated soil for heavy-metal removal. The purpose of the experiment was to determine the availability to sunflower (Helianthus annuus L.) and hybrid poplar (Populus deltoides Marsh. × P. nigra L.) seedlings, of non-essential (Cd, Ni, Pb) and essential heavy metals (Cu, Fe, Mn, Zn) in field soil injected with biosolids since 1976 and treated with ethylenediamine-tetraacetic acid (EDTA) in 2001. Sunflower was grown at two densities, 20000 and 60000 plants/ha, and poplar at 10000 plants/ha. The tetrasodium salt of EDTA was applied at rates of 0, 0.5, 1, and 2 g EDTA salt per kg surface (25-cm depth) soil. The EDTA did not affect uptake by poplar of the three non-essential (Cd, Ni, Pb) and four essential (Cu, Fe, Mn, Zn) heavy metals. For sunflower, the 1.0 g/kg rate of chelate addition resulted in maximal removal of the three non-essential heavy metals (Cd, Ni, Pb). Uptake of the essential heavy metals by sunflower was little affected by the EDTA. At the 20000 plants/ha density, leaves of sunflower grown with 1.0 g EDTA Na₄2H₂O per kg soil accumulated more Cd, Ni, and Pb than leaves of sunflower grown without the EDTA salt. At this density, concentrations of Cd in leaves of sunflower without EDTA and with 1.0 g/kg EDTA salt were 2.2 and 6.5 g/g, respectively; for Ni, they were 6.7 and 19.2 g/g, respectively; and for Pb, they were 15.6 and 46.9 g/g, respectively. At the 60000 plants/ha density, stems of sunflower grown with 1.0 g EDTA Na₄2H₂O per kg soil accumulated more Cd, Ni, and Pb than stems of sunflower grown without the EDTA salt. At this density, concentrations of Cd in stems of sunflower without EDTA and with 1.0 g/kg EDTA salt were 0.6 and 4.6 g/g, respectively; for Ni, they were 1.7 and 17.6 g/g, respectively; and for Pb, they were 5.2 and 42.8 g/g, respectively. Removal of the non-essential heavy metals by sunflower was greater at the higher plant density (60000 plants/ha) compared to the lower one (20000 plants/ha).     

Dynamics of fruit-body production and mycorrhiza formation of ectomycorrhizal ammonia fungi in warm temperate forests in Japan

To investigate the quantitative correlation between dynamics of ectomycorrhiza (ECM) formation and fruit-body production of the ammonia fungi, we treated forest soils in two ECM forests, a Castanopsis cuspidata forest and a Quercus serrata forest, in warm temperate Japan with urea to induce fruiting of ammonia fungi. We identified the ectomycorrhizae of two known species of ammonia fungi, Alnicola lactariolens and Hebeloma vinosophyllum, using morphological typing and PCR-RFLP. ECM initiation, increase, and subsequent decrease preceded the start, increase, and decrease of fruit-body production for each species. We also found many kinds of ECM fungi that did not develop fruit bodies after urea treatment during the observation period, which suggests that it is necessary to expand the definition of ammonia fungi from one that refers solely to the species reproducing on the ground to one which includes those in somatic forms in the soil.     

Recovery of mycorrhizas of a fungus, <Emphasis Type="Italic">Cenococcum geophilum</Emphasis>, after urea treatment in warm temperate forests in Japan

We studied recovery of the ectomycorrhizal species Cenococcum geophilum (Cg) after urea treatment in two types of vegetation. The recovery was as quick as 6 months after the treatment and overlapped the fruiting period of ectomycorrhizal ammonia fungi. Ectomycorrhizas investigated as Cg belonged to a single species irrespective of treatment and vegetation type. Cg ectomycorrhizas were significantly more abundant in density in nontreated soil than in treated soil. Between vegetation types, Cg ectomycorrhizas were significantly more in density in broad-leaved deciduous forest than in broad-leaved evergreen forest. Moreover, Cg was dominant in the nontreated soils of the former type of forest.     

Components of spatial patterning in a serpentine grassland

We analyzed the components of spatial patterning in species abundance in a diverse grassland dominated by early season, annual forbs. Species abundance, soil depth and gopher disturbances were measured by means of a nested spatial design on two 8m×20m plots that differed in the amount of larger scale variability in soil depth. Species distributions at the scale of the 10cm×10cm quadrat were highly clumped, with a decline in clumping with mean abundance. Even with the effect of abundance on clumping removed, species showed differences in the degree of clumping and these differences were consistent between the two plots. The abundance of the species and the frequency of disturbance correlated weakly to moderately with soil depth. Semivariance analyses indicated that the most common species all showed complex spatial patterning at a range of scales. Some of this variation corresponded to patterns of soil depth variation and patterns of gopher disturbance; however, a large amount of the spatial patterning in species abundance remains unexplained.     

Flood disturbance and riparian species diversity on the Colorado River Delta

We investigated the influence of channel migration and expansion on riparian plant species diversity along the lower Colorado River near the United States–Mexico border. Using repeat aerial photography in a GIS we identified and classed areas of low, moderate, and high disturbance frequency caused by channel expansion and migration. Replicate vegetation plots (12m×12m) were sampled in each of the three disturbance classes. One-way ANOVA was used to test for differences in species richness, species diversity (using the Shannon–Weiner Index) and overall percent ground cover of plants between the three disturbance classes. Regardless of disturbance class, plots were dominated by trees or shrubs, especially the non-native Tamarix ramosissima, as well as Pluchea sericea, Baccharis salicifolia and Salix goodingii. Clearly woody species constitute the great bulk of overall species richness, percent ground cover, and species diversity (H) in each disturbance group. No overall statistically significant differences were revealed among the disturbance groups for values of species richness, percent ground cover, or the Shannon–Wiener Index, though paired contrasts of means revealed that total percent ground cover on low disturbance plots was significantly higher than on moderately disturbed plots. Spatial and temporal variability in riparian diversity in the study area appears to hinge on factors other than disturbance frequency such as salt or drought stress. Alternately, our results could be interpreted as suggesting that in the presence of intensive flow regulation, disturbance plays a secondary role to ecological stresses, similar to that demonstrated by others. Intentional flood pulses are advocated as a restorative management strategy for improving plant productivity, management of exotic species (particularly T. ramosissima), and restoration of overall biodiversity.     

Spatial distribution of canopy and subcanopy species along a sloping topography in a cool-temperate conifer-hardwood forest in the snowy region of Japan

The spatial distributions of canopy and subcanopy species (50cm stem length) were investigated within a plot extending from the top of a ridge to the valley bottom in a cool-temperate old-growth mixed forest, dominated by Cryptomeria japonica and Fagus crenata, in the snowy region of Japan. Based on the longitudinal profile of the slope, the study slope was divided into the relatively gentle upper slope position (US), the steep lower slope position (LS), the flat valley bottom (VB) and the boundary zone between the upper and lower slopes (BS). Spatial dispersal and the association patterns of species were analyzed in upperstory (10cm d.b.h) and understory (<10cm d.b.h) layers. Dominant species in the upperstory layer abruptly changed from Cryptomeria to Fagus at the BS site. In contrast, the understory trees of many species, including shade-intolerant and evergreen species, were independent of the location of conspecific upperstory trees or canopy gaps and extended their distributions on and around the BS site. Significant, diverse canopy and subcanopy species occurred at this site in both upperstory and understory layers. On the BS site, which is the lower margin of Cryptomeria-dominated vegetation, there were many medium-sized C.japonica that were killed by uprooting or breaking of the stems as a result of heavy snow pressure. It is suggested that the snow pressure gradient along a slope has a strong influence on community structure and the maintenance of diverse canopy and subcanopy species in this snowy mixed forest.     

Light utilization and competition between Echinacea purpurea, Panicum virgatum and Ratibida pinnata under greenhouse and field conditions

Competitive interactions were compared under field and greenhouse conditions for three representative tallgrass prairie species, Echinacea purpurea, Panicum virgatum and Ratibida pinnata. These were planted in monoculture and in mixtures of two species using a replacement series design with groups of four or eight plants. Competition was determined from shoot dry weight data collected during 120days in the greenhouse and after 415days in the field. Yields declined with increased density of a single species in the greenhouse from 40days onward and in the field. Relative yields were up to 100% higher in mixtures than in monocultures for all species early on in the greenhouse experiment. Later in the experiment and in the field relative yields of E.purpurea decreased in the presence of P.virgatum and R.pinnata, whereas relative yields of these two species increased in the presence of E.purpurea. There were correlations in relative yield between the field and the greenhouse experiment at 80 and 120days. In the greenhouse P.virgatum maintained higher net assimilation rates than the other species. Relative growth rates of all species were higher in monoculture and in mixtures up to 40days, after which they declined, especially for E.purpurea in mixtures. In the field, higher light intensities occurred in pure stands of E.purpurea than in mixed stands with other species. The order of competitive ability that was apparent from these field and greenhouse studies, P.virgatum=R.pinnata>E.purpurea, could be partially explained by photosynthetic rates in relation to canopy light interception.     

Ecological classification of Nigerian mangroves using soil nutrient gradient analysis

Direct gradient analysis was used to relate the structure of mangrove communities to soil nutrient gradients. The predominant cations in the alluvial soils were magnesium and calcium, the values ranging from 8.6±0.9 to 24.6±2.0me per 100g. Organic carbon was high in the soils, ranging from 3.5% to 10.4%. All soil nutrients varied seasonally, in response to wet and dry periods of the climate. Correlation of species with soil nutrients indicated the nutrient status of the soils to be best defined in terms of calcium for the A stratum (species > 3m tall), calcium/postassium for the B stratum (species 1–3m tall) and magnesium for the C stratum (species < 1m tall). Ecological group classification shows that Avicennia africanaand Nypa fruticansoccurred almost exclusively at the highest calcium values of 20.8 and 17.6me per 100g, respectively. Acrostichum aureumand Sesuvium portulacastrumare insensitive to the magnesium gradient. The analysis revealed an overlapping range of occurrences for most of the species although with varying ecological optima along the gradient.     

Floristic composition, structure, and diversity of four forest plots in the Sierra Maigualida, Venezuelan Guayana

A phytosociological study was carried out in four 1-ha forest plots in the Sierra Maigualida region, Venezuelan Guayana. Density, dominance, and frequency values were calculated as well as the species and family importance values (FIVs) in each plot. A total of 65 families, 232 genera and 533 species were represented in the 4ha of forest. The number of stems 10cmdbh varied from 355 to 563, the number of species from 133 to 191, the genera from 76 to 120, the families from 38 to 51, and the basal area from 20.56 to 40.83m² per hectare. Overall the most species rich family was Fabaceae (38 species), the most numerous in total stems was Burseraceae (165 individuals), and the most dominant in terms of basal area was Sapotaceae (1367.13cm²). The most conspicuous families, as represented among the top five FIV, include Burseraceae in all four plots, Moraceae in three of the plots, and Sapotaceae in two plots. Less than 20% of the total inventory of species are represented in two or more plots. The percentages of species which are unique to a single plot range from 56 to 67%. The within-plot diversities recorded in the present study indicate that the Sierra Maiguailida harbors the richest forests thus far documented in Venezuelan Guayana. Meanwhile, the low between-plot similarity indices reinforce the notion that the species richness of this region is unusually high and suggest the need to extend collections and inventory studies.     

Patterns of floristic diversity in semi-natural coastal vegetation of Lebanon and implications for conservation

The current understanding of the status of the vegetation in Lebanon is largely derived from herbarium data and associated floristic studies produced by early 20th century field botanists. In common with other areas in the Mediterranean, the Lebanese coastline is highly threatened by unregulated development, yet current patterns of species richness along the Lebanese coastal zone are little studied. The objective of this study was to assess the floristic richness of the Lebanese coastal zone and to provide baseline information for conservation planning. For this purpose, permanent sample plots (6m×100m) were established in 26 selected vegetation communities in coastal habitats. Monthly field collections of plant specimens were undertaken between October 1999 and July 2000. A total of 441 species were collected and identified. None of the recorded species are currently considered globally threatened, but two are Lebanese endemics (Matthiola crassifolia Boiss. & Gaill., Origanum ehrenbergii Boiss.). Species richness varied between communities, ranging from six species in a littoral limestone pavement community to 113 in an abandoned terrace community. The similarity between communities, based on Sorensen indices, was low and a large number of species were recorded only once. Cluster analysis showed a grouping of different communities within locations in some instances and the clustering of similar community types regardless of location in others. Species richness in riparian and littoral communities consisted mostly of habitat non-specific species. The low community similarity, patchy species distribution, and predominance of habitat non-specific species all point to the need to complement in situ conservation measures with ex situ conservation.     

Interactions among ammonia fungi on MY agar medium with varying pH

Five early-phase ammonia fungi (EP fungi) – Amblyosporium botrytis, Ascobolus denudatus, Peziza moravecii, Pseudombrophila petrakii, Coprinopsis phlyctidospora, and Tephrocybe tesquorum, and one late-phase ammonia fungus (LP fungus), Hebeloma vinosophyllum – were co-cultured on malt extract-yeast extract agar media at pH 5.5, 7.0, 8.0, and 9.0. The co-cultures among the early-stage EP fungi Amblyosporium botrytis, Ascobolus denudatus, Peziza moravecii, and Pseudombrophila petrakii, generally did not inhibit or accelerate the reproductive structure formation of the opposed fungi. Among the EP fungi, Am. botrytis, As. denudatus, and Pe. moravecii intermingled with each other. The late-stage EP fungus T. tesquorum inhibited the growth of other EP fungi. Another late-stage EP fungus, C. phlyctidospora, showed ability to invade other EP fungi, but it did not deeply invade into the territories of early-stage EP fungi. The LP fungus H. vinosophyllum tended to accelerate basidioma formation of C. phlyctidospora at pH 5.5 and 9.0. H. vinosophyllum formed the highest numbers of basidomata at pH 5.5. These results show that successive occurrence of ammonia fungi is caused by the interspecific interactions among ammonia fungi as well as by the physiological characteristic of each fungus associated with conditions of its inhabiting soils, such as pH and nitrogen concentration.     

A Cytogenetic Study of the Leaf Beetle Genus Cyrtonus (Coleoptera, Chrysomelidae)

The chromosomes of ten species of Cyrtonus and the genome sizes of six are surveyed. Among the total of 15 chromosomally studied species, 11 have 2n=28 chromosomes and a 13+Xy_p male meioformula, three have 2n=40 and 19+Xy_p and one 2n=46 and 22+Xy_p. All but one species with 28 chromosomes show only metacentric or submetacentric chromosomes, whereas the species with 40 and 46 chromosomes display some telocentrics or subtelocentrics, that are probably derived from the former by centric fissions. However, since the number of major chromosome arms is strikingly higher in these latter species (NF=70 and 78) than in the 28-chromosome species (mostly NF=56), other chromosomal rearrangements such as pericentric inversions or heterochromatin accretions could also be involved. The genome sizes display a narrow range, from 1C=0.6–1.22pg, and they are not significantly correlated with the chromosome numbers. Some possible factors implied in the rough chromosomal evolution of Cyrtonus are discussed in relation to a few other genera of the subfamily Chrysomelinae.     

Different impacts of two species of aphid-attending ants with different aggressiveness on the number of emerging adults of the aphid’s primary parasitoid and hyperparasitoids

The impacts of two species of ants (Lasius niger and Pristomyrmex pungens) attending the cotton aphid (Aphis gossypii) on the number of emerging adults of the aphids primary parasitoid (Lysiphlebus japonicus) and hyperparasitoids were assessed experimentally at a no-pesticide mandarin grove. L.japonicus females were observed foraging frequently in aphid colonies attended by either ant species, with more females in P.pungens-attended than in L.niger-attended colonies, but rarely in aphid colonies where ants were artificially excluded. Females were less often attacked by P.pungens workers than by L.niger workers, so that they stayed longer and oviposited into more aphids in P.pungens-attended than in L.niger-attended colonies. Attendance by each ant species reduced predator numbers in aphid colonies, compared to colonies where ants were absent, although P.pungens was slightly less effective in repelling predators. Therefore, both ant species incidentally protected parasitized aphids from predators. Consequently, L.japonicus-mummies were abundant in colonies attended by either ant species, with more mummies in P.pungens-attended colonies, and were scarce in ant-excluded colonies. The hyperparasitism and predation on L.japonicus larvae within mummies occurred more frequently in P.pungens-attended than in L.niger-attended colonies, but mummy predation rate was only 20% in the former. As a result, the number of emerging L.japonicus adults did not differ significantly between aphid colonies attended by the two ant species, but significantly more hyperparasitoids emerged in colonies attended by the relatively less aggressive P.pungens than in colonies attended by L.niger.     

Effects of climate on the radial growth of tree species in the upper and lower distribution limits of an altitudinal ecotone on Mount Norikura,central Japan

Tree-ring width chronologies were developed for Abies veitchii, Betula ermanii and Betula platyphylla var. japonica in their altitudinal ecotone (approximately 1600m a.s.l.) on Mount Norikura, central Japan, to determine what climatic conditions affect the growth of tree species in the upper and lower distribution limits of an altitudinal ecotone. This altitude was the lower distribution limit for A.veitchii and B.ermanii in the subalpine zone, and was the upper distribution limit for B.platyphylla var. japonica in the montane zone on Mount Norikura. Tree-ring widths of the two Betula species and A.veitchii were positively correlated with the August precipitation of the current and previous years, respectively. Precipitation in August (the hottest month) was reduced compared with other months during summer. Tree-ring width of B.platyphylla var. japonica showed no correlation with temperatures in any month in its upper distribution limit. In contrast, tree-ring widths of B.ermanii and A.veitchii were negatively correlated with the August temperatures of the current and previous years, respectively, at the lower distribution limit of these species. Therefore, the two Betula species and A.veitchii responded to climatic conditions of the current and previous years, respectively. The present study also suggests that a water deficit in August reduces growth of these three species in this altitudinal ecotone, irrespective of the upper or lower distribution limits, and that a high August temperature is more detrimental to the growth of A.veitchii and B.ermanii in their lower distribution limits. Thus, the three species with different altitudinal distributions examined in the present study responded differently to climatic conditions in this altitudinal ecotone on Mount Norikura.     

Developmental morphology of the cyprinid fish Horadandia atukorali

Embryonic, larval, and juvenile development of a small Indian cyprinid, Horadandia atukorali, is described from laboratory-reared specimens. The eggs, measuring 0.7–0.8mm in diameter, were demersal, almost spherical in shape, transparent and unpigmented, with a pale yellow yolk without oil globules. Hatching occurred 47–54h after fertilization at 26.3–27.5°C. The newly hatched larvae, measuring 2.3–2.6mm in body length (BL) with 16+13=29 myomeres, had no melanophores, except on the eye, a single melanophore occurring on the lower margin, and xanthophores surrounding the pupil. The yolk was completely absorbed at 3.0mm BL. Notochord flexion was initiated at 4.0mm BL and finished at 4.4mm BL. Aggregate numbers of all fin rays were completed at 8.0mm BL. Squamation was initiated at 6.4mm BL and completed at 9.5mm BL. Although the eggs of Horadandia atukorali resembled those of other small danionin species, including Aphyocypris chinensis, Chela dadiburjori, Danio rerio, Devario malabaricus, and Hemigrammocypris rasborella, they differed from those of Danio rerio and Devario malabaricus in having a narrower perivitelline space. The larvae and juveniles of Horadandia atukorali were also similar to those of the latter five species in general morphology, especially in the presence of a melanophore on the lower margin of the eye at hatching, as in C. dadiburjori. However, the early life stage morphology of Horadandia atukorali differed from the other danionin species in having a conical yolk sac at hatching, no cement organ on the forehead in the yolk-sac larval stage, a divided gas bladder in the flexion larval stage, two dark lateral streaks on the head and chevron-like melanophores on the ventral body surface from the preflexion to postflexion larval stages, and xanthophores on the eyes at hatching.     

Competition between <Emphasis Type="Italic">Eucalyptus victrix</Emphasis> seedlings and grass species

Competition in a natural system may be interspecific or intraspecific. In semiarid ecosystems, competition for resources between established neighboring grass species and newly recruited seedlings is very high. To examine the effects of grass species density, growing space and time of establishment on Eucalyptus victrix seedlings (interspecific competition), and the effect of density and growing space within E.victrix (intraspecific competition) we conducted an experiment under controlled conditions. We tested four hypotheses (i) E.victrix seedling growth is not affected by grass density; (ii) there is no difference in E.victrix survival and growth between early and later grass establishment; (iii) interspecific competition is not more intense than intraspecific competition in E.victrix; and (iv) growth of E.victrix seedlings is not dependent on available growing space. In a monoculture of E.victrix, seedling mortality was higher (10%) in large pots. In mixed culture pots, where E.victrix seedlings and grass seedlings were planted on the same day, E.victrix seedlings survived for up to 4weeks, but started to die after week five in the smallest pots. However, mortalities occurred in pots of all sizes when grass was established before E.victrix seedlings. Results also indicated that the resources necessary for the growth of individual E.victrix seedlings were more limiting under conditions of increased density of neighboring grass species rather than intraspecific competition. In particular, photosynthetic area of E.victrix seedlings was drastically reduced in mixed cultures. Although density, pot size and time of planting had impacts on E.victrix seedlings, the patterns of these impacts were variable.     

Cowdria Ruminantium Antibodies in Acaricide-Treated and Untreated Cattle Exposed to Amblyomma Variegatum Ticks in The Gambia

An indirect enzyme-linked immunosorbent assay (ELISA), based on the major antigenic protein 1 fragment B (MAP1-B) of Cowdria ruminantium, was used to assess seroprevalence in cattle in The Gambia. Two groups of 20 N'Dama and 20 Gobra zebu cattle were monitored for 12 months with flumethrin treatment and for another 10 months without acaricidal treatment. Two groups of 20 N'Dama and 20 Gobra cattle served as untreated controls. During the period of acaricidal treatment, the cumulative proportions of positive serum samples were 25.6±5.6% (±confidence interval) and 34.7±6.8% in treated N'Dama and Gobra cattle respectively; the proportion of positive sera in untreated cattle was 52.2±6.9% in N'Damas and 61.4±7.3% in Gobras. Within breed, difference in antibody prevalence between treated and untreated cattle was significant (P<0.001) but between breed differences were not significant. In the 10 months following suspension of acaricide application, there was an increase of proportion of positive serum samples in previously treated N'Dama and Gobra cattle. In both previously treated and untreated animals the peak of positive seroreactions occurred during and subsequent to the period of activity of Amblyomma variegatum adults. Cumulative seroprevalences in previously treated N'Dama and Gobra cattle were 32.6±6.9% and 44.7±8.5%, respectively; in untreated animals seroprevalence was 38.6±7.2% in N'Dama and 65.3±8.4% in Gobra cattle. Throughout the study period, within the N'Dama breed, the seropositive rate in previously treated cattle did not differ from that in untreated animals. Conversely, within the Gobra breed, the number of positive seroreactions was higher (P<0.002) in untreated animals than in previously treated cattle. These results provide a support for designing A. variegatum and heartwater control strategies, if necessary, in The Gambia in relation to cattle breeds.     

Ammonia fungi of iriomote Island in the southern Ryukyus,Japan and a new ammonia fungus,Hebeloma luchuense

Species composition and fruiting season of ammonia fungi were investigated in Iriomote Island of the southern Ryukyus, Okinawa Prefecture, Japan.Castanopsis andPinus forests were surveyed and 10 species of ammonia fungi were collected, including one new agaric species,Hebeloma luchuense sp. nov. This new fungus is characterized by having a rooting, squamulose-scaly stipe and cortinate veil and forms ectomycorrhizae withCastanopsis cuspidata var.sieboldii. Although the general mushroom season in theCastanopsis forest in Iriomote island was very short and restricted to summer, ammonia fungi were observed to fruit throughout the year in urea-treated plots.     

Stem distribution and clonal structure of Chamaecyparis pisifera growing in an old-growth beech-conifer forest

To elucidate sapling patch formation and the mode of regeneration occurring in Chamaecyparis pisifera, we investigated stem distribution and clonal structure of this species in an old-growth beech-conifer forest in central Japan. The study was carried out in a 1-ha plot using small and large sapling (d.b.h.<5cm, 0.5mheight<2 m and d.b.h.<5cm, height2m, respectively) and adult (d.b.h.5cm) stems of Chamaecyparis pisifera. The numbers of small and large sapling stems were 677 and 149 in the plot, respectively, and they were strongly aggregated. Adult stems occurred at much lower density (90 stems in the plot) and were weakly clustered. Fifty multilocus genotypes at nine allozyme loci were detected among sampled stems. Small and large sapling stems with identical genotypes showed aggregated distribution, while some neighboring adult stems had the same genotypes. Spatial autocorrelation of alleles in small and large sapling stems revealed a strongly positive association among stems within a distance of 10m; but a negative association as distance increased. In adult stems, a strongly positive value was found only in the shortest distance class. These results indicate that clonal growth by layering occurred at the sapling stage and contributed to patch formation. Our results also suggest that the clonal growth by layering is ecologically significant throughout the life history of Chamaecyparis pisifera, particularly as an important strategy for the sapling establishment in the early stage of regeneration process.