Microhabitat Types Research Articles

Associação de aves a agrupamentos de bambu na porção Sul da Mata Atlântica, Londrina, Estado do Paraná, Brasil

Agrupamentos de bambu têm sido considerados relativamente importantes para um grande número de espécies de aves, principalmente na Amazônia. No presente estudo avaliamos as variações na abundância de aves associadas ao bambu Chusquea sp. em áreas com diferentes disponibilidades deste microhábitat no interior de floresta nativa, na porção sul da Mata Atlântica, Estado do Paraná. Amostragens por ponto-de-escuta foram realizadas durante 25 dias em cinco trilhas, três em áreas com agrupamentos de bambu e duas em áreas onde este microhábitat estava ausente; as trilhas diferiram na disponibilidade de bambu. As áreas de estudos foram o Parque Estadual Mata dos Godoy e um fragmento florestal adjacente que, juntos, formam uma área maior que 2.000 ha no Norte do Estado do Paraná, Sul do Brasil. Das dezenove espécies de aves analisadas, apenas cinco foram registradas nas trilhas onde não havia bambu. Cinco espécies diminuíram significativamente suas abundâncias de acordo com a disponibilidade decrescente de aglomerados de bambu (teste-G, P < 0,01). Nenhuma espécie de ave apresentou maior abundância nas trilhas onde o bambu estava ausente. Diferente da Amazônia, agrupamentos de bambu na porção sul da Mata Atlântica brasileira não formam áreas extensas, sendo encontrados mais esparsos pelo sub-bosque. Ainda assim, este microhábitat pode ser importante para a conservação de certas espécies de aves na Mata Atlântica.

Radiotelemetric Study of Movement Patterns of Lotic Freshwater Turtles during Breeding and Hibernation Seasons

ABSTRACT We conducted a radio tracking study to assess movement patterns and microhabitat use of lotic turtles during their nesting and hibernation seasons. During the nesting season, female turtles moved from the sandbank along the river to the outer-embankment and/or inner-embankment that includes rice fields. The maximum movement distance was over 2.5 km. Turtles frequently utilized terrestrial microhabitats for basking but also for other activities such as feeding and resting. Calm, deep aquatic sites near banks were used for hibernation. These results indicate that large areas that include different microhabitat type (both aquatic and terrestrial) are essential for freshwater turtles inhabiting river environments.

Dispersal and habitat fidelity of bog and forest growth forms of Hawaiian Metrosideros (Myrtaceae)

The Hawaiian endemic Metrosideros polymorpha is known for its high levels of morphological diversity and localized adaptation to a range of habitats. At the ecotone between bogs and forests, individuals exhibiting morphological extremes can be found within a few metres of each other. The objective of this study was to examine the genetic diversity and structure of morphologically distinct neighbouring populations of M. polymorpha, growing in bogs and adjacent forests across multiple islands. We explored these relationships using the molecular technique of inter-simple sequence repeats (ISSRs). The majority (90.79%) of genetic variation was found within populations, 8.53% of the differentiation among populations can be attributed to differences between microhabitat types within islands and very little of the genetic differentiation is explained by the differences among islands (0.68%). These high levels of genetic homogeneity across populations could be the result of extensive gene flow and/or recent isolation of populations. We introduce a nearest genetic neighbour (NGN) analysis to examine detailed relationships of dispersal within and among populations by habitat and island. Using this approach, we provide evidence for habitat fidelity within bog populations and a positive correlation between island age and the proportion of same-island NGNs.

Forest Soil Heterogeneity and Soil Sampling Protocols on Limestone Outctops: Example from SW China

Forest soil heterogeneity of outcrop karst was studied by testing soil organic carbon at a selected 20 m × 30 m plot set up in Maolan primitive karst forest area, southern Guizhou Province, China. 90 microhabitats in the plot are roughly classified into 7 distinct microhabitat There was great heterogeneity in the plot not only for soil distribution but for great difference of soil organic carbon content. Soil organic carbon (SOC) contents were much higher, ranging from 40.1 g/kg to 203.5 g/kg. The CV (coefficient of variation) value of SOC from 38 soil sampling points, 22 sampling microhabitats, each microhabitat type, and individual microhabitat was 43%, 41%, 2.2% to 42%, 14% to 57.3% respectively. This showed high soil heterogeneity in terms of soil distributing pattern, size and soil organic carbon SOC content in outcropped karst. Different methods were applied to calculate SOC content in the plot. Small discrepancies suggested that the mixed soil samples collected from the major microhabitat types covering 95% soil distributing area were capable of representing soil nutrient status of the whole plot.

Small-scale spatial variation of benthic algal assemblages in a peat bog

Spatial patterns on a very small scale (10 cm), and the effect of artificial barriers on the composition of phytobenthic algal assemblages along two transects within different microhabitat types were investigated. Samples were taken in a peat bog along linear transects on a scale of 10 cm, and water chemistry was examined. The distribution of algae along both transects was influenced by both spatial distance and environmental conditions in similar proportions. Differences in species composition in various parts of the transects were observed, but this pattern was primarily related to the abundance of species, rather than to their presence/absence in samples. Similarity in species composition correlated with spatial distance and environmental parameters in both microhabitat types. I concluded that, given a homogenous environment on a small scale, spatial distribution of algae is affected by both the environmental conditions of the microhabitats and their dispersal limitations. Moreover, an artificial barrier constituted an obstruction for water and nutrient flow, as well as algal migration, and had an impact on species composition.

Vertical Micro‐Zonation of Testate Amoebae and Ciliates in Peatland Waters in Relation to Potential Food Resources and Grazing Pressure

AbstractThe aim of this study was to examine the community structure and vertical micro‐distribution of testate amoebae and ciliates in a raised bog in eastern Poland, as well as to assess the influence of potential food resources (Chl‐a, bacteria, heterotrophic flagellates) and predators (rotifers and copepods) on protozoa communities. Samples were taken from surface, bottom and interstitial waters. At each type of micro‐habitat and each sampling date water was sampled using a plexiglass corer or mini‐piezometers. Additionally, in order to evaluate grazing pressure, field enclosures were used in which metazoan abundance and composition was manipulated by size‐fractionation. Over experiments, metazoan populations shifted from dominance of rotifers to copepods. In the first experiment, with rotifers dominating, metazoa had only a modest predatory impact on the protozoa. In contrast, the second experiment, with copepods prevailing, demonstrated a clear top‐down control of the protozoa communities by metazoan. The density and biomass of protozoa significantly differed between the studied stations, with the lowest numbers in the interstitial water and the highest in the surface water. Surface sampling were dominated by mixotrophic taxa, whereas the deepest sampling level was characterized by increase in the proportion of bacterivore species. These differences between micro‐habitats may be due to differences in environmental conditions (food resources and grazing pressure). Ordination analysis revealed that bacteria can strongly regulate the abundance and taxonomic composition of protozoa in the bottom and interstitial waters. Metazoan predators could be the main regulators of protozoa communities in surface water. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Spatial scale and the diversity of macroinvertebrates in a Neotropical catchment

Summary1. Lotic ecosystems can be studied on several spatial scales, and usually show high heterogeneity at all of them in terms of biological and environmental characteristics. Understanding and predicting the taxonomic composition of biological communities is challenging and compounded by the problem of scale. Additive diversity partitioning is a tool that can show the diversity that occurs at different scales.2. We evaluated the spatial distribution of benthic macroinvertebrates in a tropical headwater catchment (S.E. Brazil) during the dry season and compared alpha and beta diversities at the scales of stream segments, reaches, riffles and microhabitats (substratum types: gravels, stones and leaf litter). We used family richness as our estimate of diversity. Sampling was hierarchical, and included three stream segments, two stream reaches per segment, three riffles per reach, three microhabitats per riffle and three Surber sample units per microhabitat.3. Classification analysis of the 53 families found revealed groups formed in terms of stream segment and microhabitat, but not in terms of stream reaches and riffles. Separate partition analyses for each microhabitat showed that litter supported lower alpha diversity (28%) than did stones (36%) or gravel (42%). In all cases, alpha diversity at the microhabitat scale was lower than expected under a null model that assumed no aggregation of the fauna.4. Beta diversity among patches of the microhabitats in riffles depended on substratum type. It was lower than expected in litter, similar in stone and higher in gravel. Beta diversities among riffles and among reaches were as expected under the null model. On the other hand, beta diversity observed was higher than expected at the scale of stream segments for all microhabitat types.5. We conclude that efficient diversity inventories should concentrate sampling in different microhabitats and stream sites. In the present study, sampling restricted to stream segments and substratum types (i.e. excluding riffles and stream reaches) would produce around 75% of all observed families using 17% of the sampling effort employed. This finding indicates that intensive sampling (many riffles and reaches) in few stream segments does not result in efficient assessment of diversity in a region.

Seasonal Variability in Community Structure and Habitat Selection of Mayflies (Ephemeroptera) in the Nišava River (Serbia)

ABSTRACTThe sedentary nature of many members of the river macroinvertebrate community allows spatial and temporal analyses of disturbance effects. This characteristic also implicates their strong affinity towards certain types of microhabitats. The results of the mayfly (Ephemeroptera) community structure analysis in the Nisava River (Serbia) have shown a clear dependence of the mayfly community on habitat type (solid vs. loose bottoms), physical and chemical parameters (nutrient content), and season. Over a one-year period, on a monthly basis, 28 species of mayfly were identified at 12 localities along the 151 km long stretch of the Nišava River. The community structure changed longitudinally with the changes of physical and chemical parameters and habitat type. The lowest Shannon's diversity index was estimated for the localities with the lowest percentage of solid bottoms (rock, pebble). The highest diversity index was estimated for localities with the highest percentage of solid bottoms and the lowest average content of phosphorus and nitrogen.

Seasonal variability of periphyton nutrient status and biomass on artificial and natural substrates in a tropical mesotrophic reservoir

AIM: Study aimed at evaluating the periphytic community seasonal variation, nutrient status and biomass on artificial and natural (Nymphaea spp., Utricularia foliosa Linnaeus) substrates at a shallow mesotrophic reservoir (Ninfeias Reservoir) located in the Parque Estadual das Fontes do Ipiranga, Sao Paulo, southeast Brazil; METHODS: Samplings for physical, chemical and biological characteristics was performed in winter (August-2006), spring (October-2006), summer (January-2007) and autumn (April-2007). Periphyton was collected growing on artificial (microscope glass slides, 28 days colonization) and natural substrate (Nymphaea spp. and Utricularia foliosa). Periphyton attributes studied were: chlorophyll a, dry mass, ash free dry mass, and N and P content; RESULTS: During the study period was recorded the highest values of water transparency and DO in the winter, PO4-P and free CO2 in the spring, temperature and phytoplankton biomass in summer and autumn of DIN. The highest biomass values were recorded in winter and autumn. Periphyton P and N content varied seasonally on the substrates. Nymphaea spp. had the highest periphyton P content in summer, while U. foliosa and artificial substrate presented in the spring. Higher periphyton N content in Nymphaea spp., U foliosa and artificial substrate was recorded in the spring, winter and autumn, respectively. Periphyton and water ratio N: P molar indicated P-limitation, except the water in the spring (N-limitation). CONCLUSION: Periphyton N and P content and biomass variation was controlled by the seasonal scale. However, the microhabitat type seems to influence the periphyton nutrient status, especially in low nutrient availability in the environment.

Does sampling method or microhabitat type determine patterns of macroinvertebrate assemblage structure detected across spatial scales in rivers?

Patterns in macroinvertebrate assemblage structure detected across spatial scales in rivers vary among studies, and it is not clear whether methodological differences in sampling methods or differences between rivers are responsible. We aimed to separate the roles of microhabitats and sampling methods in determining patterns in macroinvertebrate assemblages across spatial scales in the Johanna River, south-eastern Australia. We hypothesised that less sample-to-sample variability in the structure of macroinvertebrate assemblages would be detected using a Sürber sampler than by scrubbing stones. However, Sürber samples were more variable than individual stones, although invertebrate abundance did not differ. To examine the effect of habitat and substratum, we hypothesised that taxa richness, invertebrate abundance and sample variability would differ among leaf packs and stones. Variation among samples in taxa richness and abundance was higher among leaf packs than among cobbles, whereas variability in taxon composition was much higher among stones. Leaf packs in runs had four times as many taxa as did stones in riffles, and more individuals. Leaf packs may therefore provide a more representative sample of the assemblage than do stones. Sürber samplers may randomly subsample riffle assemblages, inflating the sample-to-sample variability detected.

Biological invasion of a refuge habitat: Anthriscus caucalis (Apiaceae) decreases diversity, evenness, and survival of native herbs in the Chilean matorral

In central Chile, the bur beak chervil (Anthriscus caucalis M. Bieb.; Apiaceae) is an annual naturalized herb introduced from Europe at least 120 years ago. Anthriscus is distributed in vegetation formations such as sclerophyllous shrublands (locally known as “matorral”) and spiny savannas of Acacia caven (locally known as “espinal”). In matorral formations, Anthriscus grows at the edge of native woody fragments. Because these fragments are refuges where native herbs recruit, we studied the impact of Anthriscus on the diversity and survival of native forbs established in these sheltering microsites. First, we characterized the spatial distribution of Anthriscus in the matorral, sampling in different micro-habitat types. We differentiated three microhabitat types: under the canopy of a fragment, at the edge of the canopy of a fragment, and in open sites outside the fragments. A total of 40 1 × 1 m quadrates were randomly distributed in each habitat type. Inside each of them, we recorded the number of seedlings and established plants, including Anthriscus. Then we evaluated experimentally the effect of Anthriscus on diversity and evenness of the local herb assemblages. For this purpose we conducted a field trial using 34 metallic enclosures (0.5 × 0.5 m) arranged in pairs. In each pair, Anthriscus individuals were removed from one plot, the other paired plot acting as control. We periodically recorded the presence and abundance of the remanent species of herbs inside the plots, and then we characterized the species diversity and evenness over time (Shannon’s index, H′ and Pielou’s index, J′). Finally, in a second experiment we measured experimentally the presence or absence of Anthriscus against the survival of four native herb species (Bowlesia incana, Bromus berteroanus, Pectocarya linearis, and Moscharia pinnatifida). Here we used 20 0.5 × 0.5 m plots where we randomly transplanted seedlings of native herbs and Arnthiscus. Then, for each species and plot we determined their survival (%) according to the number of seedlings initially transplanted. The samplings show strong association between the presence of Anthriscus on edge habitat in the matorral. The maximum densities were noted in these microhabitat types whereas in open areas and under-fragment sites Anthriscus shows very low or null densities. At the end of the first trials, the plots with Anthriscus showed a Shannon diversity index H′ = 0.41 (±0.11 SE), while in plots without Anthriscus this value was 1.19 (±0.1 SE), both as averages. Pielou’s evenness index (J′) yielded values of 0.23 (±0.06 SE) and 0.59 (±0.04 SE) for treatments with and without Anthriscus, respectively. Similarly, the second trials shows that the survival of the four native herbs was drastically decreased in the presence of Anthriscus: by 64% for Bowlesiaincana, 43% for Bromusberteroanus, 46% for Moscharia pinnatifida, and 76% for Pectocarialinearis. Our study shows that the effects of Anthriscus include an inhibition of the establishment of native plants and a decrease in their survival in edge habitats, therefore affecting the composition and diversity of the local herb layer. Thus, Anthriscus is invading a refuge habitat for native herbs in the Chilean matorral, decreasing the native herb diversity and survival.

Maternal genetic correlations in the seed rain: effects of frugivore activity in heterogeneous landscapes

Summary 1. A frugivore‐generated seed rain combines dispersed propagules from source trees located all over the landscape. By selecting deposition sites, frugivorous vertebrates set the maternal genetic correlations in the seed rain, i.e. how maternal progenies become distributed over the landscape relative to the source trees and other conspecifics. This aspect, however, remains virtually unexplored despite its central effect on the demographic and genetic structure in plant populations. 2. We examined three components of maternal genetic correlations in the seed rain: the number of distinct contributing maternal trees (maternal richness), the genetic relatedness among contributing trees (maternal relatedness) and the probability that two seeds drawn from the same seed trap come from the same maternal tree (correlated maternity). 3. We studied the maternal genetic correlations in a vertebrate‐generated seed rain of a Prunus mahaleb population located in a heterogeneous landscape (c. 25 ha). Based on the multilocus genotypes provided by microsatellite markers, we identified the source tree of dispersed seeds sampled in seed traps and distributed among six microhabitat types. 4. Seed traps showed a spatial aggregation of maternally related seeds that varied among microhabitats in relation to the frugivore foraging preferences, resulting in variable maternal correlations across the landscape. We found: (i) seed traps with high maternal richness and low genetic relatedness in sites dominated by high shrubs, frequently visited by most frugivore species; (ii) seed traps with low maternal richness, high relatedness and increased correlated maternity values resulting from recurrent dispersal from few isolated source trees to sites dominated by non‐fleshy fruited species; and (iii) seed traps under pine trees with high maternal richness and relatedness (but low correlated maternity) due to long‐distance dispersal events from several source trees growing closely to each other. 5. Synthesis. Maternal progenies became distributed non‐randomly over the landscape, where trees with similar maternal neighbourhoods tended to disperse their progeny to similar microhabitats. This resulted in genetic limitation, i.e. the failure of maternal trees to reach all microhabitats, as well as the failure of the microhabitats to cast all maternal progenies. Both the genetic limitation and the spatial aggregation of maternal progenies, driven by frugivore activity, might pervasively determine recruitment and spatial genetic patterns in heterogeneous populations.

Short-term effects of retention felling at mire sites on boreal spiders and carabid beetles

Green-tree retention is an integral part of forest management in the boreal zone. Retention of small spruce mires, proposed as ‘key habitats’ for many forest organisms, is recommended while logging, but the efficiency of such practices for the maintenance of forest species is poorly understood. Hence, we studied boreal spiders and carabid beetles at 11 retained mire patches (up to 0.55 ha) in Eastern Finland during 1998–2001. The adjacent surrounding drier forests of the focal mires were clear-cut during the winter of 1998/1999. We evaluated the importance of micro-habitat type (retention, edge or clear-cut plot), time since logging, and retention-patch size in determining the assemblages of spiders and carabids. Following logging, species associated with forests and mires generally decreased both in the retained mire patches and in their adjacent clear-cuts. In a GLMM, the number of standing trees in a retention patch – a surrogate for retention-patch size – had no significant effect on most of the tested species, but plot type (retention patch, its edge or clear-cut) was significant for many species. Semi-open-habitat species and open-habitat specialists increased following logging, especially in the clear-cut plots but even within the retention patches. In contrast, mature-forest and moist-habitat specialists became significantly less abundant in clear-cuts than in retention patches following logging. Spider assemblages showed pre-harvest differences among the mires, their edges and adjacent drier forests, but the fauna of logged plots rapidly diverged from that of mire and edge plots. However, after a 1–2 summers time lag, the spider fauna of mires and edges changed toward clear-cuts. For spiders, the post-harvest sample heterogeneity was significantly lower in clear-cuts than in retention patches, including their edges. Carabid responses were generally ambiguous. Multivariate regression trees showed that the number of trees in a forest patch better determined the spider assemblage structure than study area, study year or micro-site type (retention patch, its edge or clear-cut), indicating a strong impact of logging. For carabids, however, the study area better determined the assemblage structure; the other factors were of minor importance. Our results suggest that, as the spider and carabid faunas of the retention patches had drastically changed following logging, (i) retention patches should be considerably larger than the studied size range to efficiently maintain a ‘mire core’ spider and carabid assemblage; (ii) the effect of logging may take years to appear; (iii) spiders were more sensitive to habitat change than carabids; and (iv) harvesting not only changes the relative abundances of forest- and open-habitat associated species but it may also locally decrease the faunal variation.

Diversity and community structure of harpacticoid copepods associated with cold-water coral substrates in the Porcupine Seabight (North-East Atlantic)

The influence of microhabitat type on the diversity and community structure of the harpacticoid copepod fauna associated with a cold-water coral degradation zone was investigated in the Porcupine Seabight (North-East Atlantic). Three substrate types were distinguished: dead fragments of the cold-water coral Lophelia pertusa, skeletons of the glass sponge Aphrocallistes bocagei and the underlying sediment. At the family level, it appears that coral fragments and underlying sediment do not harbour distinctly different assemblages, with Ectinosomatidae, Ameiridae, Pseudotachidiidae, Argestidae and Miraciidae as most abundant. Conclusions on assemblage structure and diversity of the sponge skeletons are limited as only two samples were available. Similarity analysis at species level showed a strong variation in the sediment samples, which did not harbour a distinctly different assemblage in opposition to the coral and sponge samples. Several factors (sediment infill on the hard substrates, mobility of the copepods, limited sample sizes) are proposed to explain this apparent lack of a distinct difference between the microhabitats. Coral fragments and sediment were both characterised by high species diversity and low species dominance, which might indicate that copepod diversity is not substantially influenced by hydrodynamical stress. The additive partitioning of species diversity showed that by adding locations species richness was greatly enhanced. The harpacticoid community in the cold-water coral degradation zone is highly diverse and includes 157 species, 62 genera and 19 families. Information from neighbouring soft-bottom regions is necessary to assess whether total species diversity is increased by the presence of these complex habitat-providing substrates.

Within‐tree distribution of nest sites and foraging areas of ants on canopy trees in a tropical rainforest in Borneo

AbstractIt has been argued that canopy trees in tropical rainforests harbor species‐rich ant assemblages; however, how ants partition the space on trees has not been adequately elucidated. Therefore, we investigated within‐tree distributions of nest sites and foraging areas of individual ant colonies on canopy trees in a tropical lowland rainforest in Southeast Asia. The species diversity and colony abundance of ants were both significantly greater in crowns than on trunks. The concentration of ant species and colonies in the tree crown seemed to be associated with greater variation in nest cavity type in the crown, compared to the trunk. For ants nesting on canopy trees, the numbers of colonies and species were both higher for ants foraging only during the daytime than for those foraging at night. Similarly, for ants foraging on canopy trees, both values were higher for ants foraging only during the daytime than for those foraging at night. For most ant colonies nesting on canopy trees, foraging areas were limited to nearby nests and within the same type of microhabitat (within‐tree position). All ants foraging on canopy trees in the daytime nested on canopy trees, whereas some ants foraging on the canopy trees at night nested on the ground. These results suggest that spatial partitioning by ant assemblages on canopy trees in tropical rainforests is affected by microenvironmental heterogeneity generated by three‐dimensional structures (e.g., trees, epiphytes, lianas, and aerial soils) in the crowns of canopy trees. Furthermore, ant diversity appears to be enriched by both temporal (diel) and fine‐scale spatial partitioning of foraging activity.

Effects of ontogenetic stage and density on the ecological role of the signal crayfish (Pacifastacus leniusculus) in a coastal Pacific stream

Ontogenetic stage and density of consumers can affect the intensity of their roles within a community. These roles can be further complicated in a heterogeneous environment, where a consumer might have disparate effects in different microhabitat types. We conducted an enclosure experiment in a small temperate stream to test the differential ecological roles of adults and juveniles of the signal crayfish (Pacifastacus leniusculus) in 2 microhabitat types. In addition, we manipulated numbers of each stage to create a gradient of density (and biomass). Enclosures contained 1, 2, or 3 adults, or 4, 8, or 12 juveniles. Control enclosures lacked crayfish. We added leaf packs the 4 corners of the enclosures to provide a primary resource for crayfish and other invertebrates and to provide a detritus-based microhabitat. After 6 wk, we collected the leaf packs and a cobble-bottom (Surber) sample from the center of the enclosures. We used cobble-bottom samples to analyze the composition of the community in the cobble microhabitat. Leaf-pack breakdown rate was positively related to crayfish biomass for adults and juveniles. Leaf-pack invertebrate community composition and abundance were negatively affected by crayfish presence, but these results were independent of crayfish ontogenetic stage and total biomass. The composition of the cobble-bottom invertebrate community was not significantly affected by the presence of crayfish, regardless of density or ontogenetic stage. This result might have been the consequence of the cannibalistic tendencies of P. leniusculus or of possible indirect effects of crayfish (e.g., bioturbation or chemical cues). Our study is among the first to be done on the ecology of P. leniusculus in its native environment. The fact that our results do not agree with those found in other studies for this organism might reflect the fact that most of what we know about this organism comes from research done where it has been introduced.

Distribution and ecology of the assemblages of myxomycetes associated with major vegetation types in Big Bend National Park, USA

The distribution and ecology of the assemblages of myxomycetes associated with four different microhabitats were studied in Big Bend National Park in Texas. During Mar. 2005, twelve plots (30 × 30 m) were established along an elevational gradient that extended from 564 to 1807 m. Samples of aerial bark from dead and living trees, aerial litter (dead but still attached plant parts), ground litter (fallen dead plant parts) and ground bark (fragments of fallen bark) were collected from these plots, which encompassed all of the major vegetation types found in the Park. Four hundred forty-seven moist chambers were prepared, and 95.8 % (428) produced some evidence (either fruit bodies or plasmodia) of myxomycetes. A total of 71 species were recorded, with ground litter yielding most (45 species). Aerial litter, aerial bark and ground bark yielded 44, 39 and 37 species, respectively. Species abundance distribution measures (diversity, dominance and similarities) varied among the four microhabitats as well as among the major vegetation types. Canonical Correspondence Analysis (CCA) showed that species distribution patterns were closely related to: (1) the major environmental-complex gradients associated with differences in elevation/temperature/moisture conditions that occur from one locality to another; and (2) the different types of microhabitat.

Revisions of the genera Parhydraena Orchymont, Protozantaena Perkins, Decarthrocerus Orchymont, and Parhydraenopsis nomen novum, aquatic and humicolous beetles from Africa and Madagascar, and comparative morphology of the tribe Parhydraenini (Coleoptera: Hydraenidae)

The hydraenid genera Parhydraena Orchymont, 1937, Decarthrocerus Orchymont, 1948, Protozantaena Perkins, 1997, and Parhydraenopsis nomen novum are comprehensively revised, based on the study and databasing of 13,323 specimens. Decarthrocerus Orchymont is considered a valid genus, not a subgenus of Parhydraena. A new generic name, Parhydraenopsis nomen novum, is provided to replace Pseudhydraena Orchymont, 1947 (a junior homonym of Pseudhydraena Acloque, 1896). The genera are redescribed, and new species are described in Parhydraena (14), Protozantaena (4), Parhydraenopsis (2), and Decarthrocerus (3). Redescriptions are provided for Parhydraena brevipalpis (Régimbart), P. lancicula Perkins & Balfour-Browne, P. seriata Balfour-Browne, Protozantaena labrata Perkins, Parhydraenopsis cooperi (Orchymont), and Decarthrocerus jeanneli Orchymont. Selected morphological features of Pneuminion Perkins, and members of the tribe Hydraenidini, Hydraenida Germain and Parhydraenida Balfour-Browne, are illustrated and compared with those of members of Parhydraenini. Keys to the genera of Parhydraenini and keys to the species of the genera revised herein are given. Male genitalia, representative spermathecae, antennae, and elytra are illustrated. Scanning electron micrographs of external morphological characters are presented. High resolution digital images of the primary types of all species (except the holotypes of three species, which could not be found) are presented (online version in color), and geographical distributions are mapped. The tribe Parhydraenini has both fully aquatic and humicolous adapted species, and shows notable diversity in the lengths of the maxillary palpi and legs, reflecting the microhabitat type. Humicolous species have relatively short maxillary palpi and tarsi, and often have a specialized body form, as in the very differently shaped members of Discozantaena and Decarthrocerus. Parhydraena has both aquatic and humicolous species, the latter being broad-shouldered species with very short maxillary palpi and tarsi. Protozantaena has one aquatic species, the four other species in the genus being collected by sifting litter in humicolous microhabitats. Species of Decarthrocerus have only been collected by sifting litter; many of the specimens are from bamboo forests. As far as is known, members of Parhydraenopsis are fully aquatic, or found in wet streamside mosses. The following new species are described (type locality in South Africa unless otherwise given): Parhydraena ancylis (Western Cape Province, Heuningnes River), P. asperita (Western Cape Province, Knysna, Diepwalle), P. brahma (Mpumalanga Province, Uitsoek), P. brunovacca (Eastern Cape Province, Umtata, Nquadu Mt.), P. divisa (Sudan, Gilo), P. sebastiani (KwaZulu-Natal Province, Cathedral Peak), P. maculicollis (KwaZulu-Natal Province, Polela River, Himeville), P. maureenae (Western Cape Province, W. Wiedouw farm), P. mpumalanga (Mpumalanga Province, Fanie Botha Trail, Maritzbos Hut area, SW Sabie), P. namaqua (Western Cape Province, Van Rhyns Pass), P. ora (Western Cape Province, Cape Town), P. parva (Western Cape Province, George, Saasveld, Kaaimans River), P. semicostata (Mpumalanga Province, Soutpansberg, Entabeni), P. toro (Western Cape Province, Kirstenbosch, Table Mountain), Protozantaena ankaratra (Madagascar, Antananarivo, Ankaratra, Reserve Manjakatompo, M. Arirana, SE drainage River Ambodimangavo), P. grebennikovi (Tanzania, W. Usambara Mts., Lushoto district, Grant’s Lodge, Mkuzu river, 3–4 km upstream of Kifungilo), P. malagasica (Madagascar, Antsiranana, Parc National Montagne d’Ambre), P. palpalis (Madagascar, Antananarivo, Anjozorobe, Ravoandrina, left affluent of River Ampanakamonty), Parhydraenopsis alta (Ethiopia, Wolamo Province, Mt. Damota), P. simiensis (Ethiopia, Simien Mountains National Park, Jinbar Wenz), Decarthrocerus bambusicus (Democratic Republic of Congo, P. N. Virunga, Volcan Sabinyo, Chanya W., W. Sabinyo), D. mahalicus (Tanzania, Mahali Peninsula, Kungure), D. mbizi (Tanzania, Mt. Mbizi, 12 mi. NE Sumbawanga).

Spatial Distribution of Algal Assemblages in a Temperate Lowland Peat Bog

AbstractSamples of phytobenthos were collected during three different seasons in 2005 along a linear transect of a lowland peat bog at various spatial scales (10 cm, 1 m, 10 m) to investigate the seasonal dynamics, diversity, and factors influencing the spatial patterns of microalgal communities. Non‐metric multidimensional scaling (NMDS), similarity percentage (SIMPER) analyses, ANOSIM, Mantel tests and diversity indices were used to analyze the data. Seasonal dynamics were exhibited by an increase in diversity, and a decrease in dominance from May to October, with significant differences in species composition. Mantel tests showed the significant influence of distance, microhabitat type, and conductivity on maintaining the similarity of species composition on scales of 1 m and 10 m. The small‐scale processes (colonization and niche differentiation), microhabitat type, geographic distance and conductivity were found to be the main factors influencing the distribution of algal assemblages. We conclude that these factors are related to winter disturbance, and the consequent colonization and subsequent niche differentiation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Litter burning does not equally affect seedling emergence of native and alien species of the Mediterranean-type Chilean matorral

Central Chile differs from other areas with Mediterranean-type climate by the scarcity of natural wildfires. The Chilean matorral is highly invaded by alien plant species from other Mediterranean zones of the world, where natural, recurrent wildfires have been one of their ecological features at least since the Pliocene. This suggests that anthropogenic fires in Chile might favour alien plant recruitment, increasing the invasive process. We assessed the effect of litter burning on the emergence of alien and native species from the soil seedbank of a matorral of central Chile. Soil samples were taken from three types of microhabitats: (i) closed matorral; (ii) beneath the canopy of shrubs and trees from an open matorral; (iii) grassland. Each sample was split in two subsamples. One subsample was exposed to fire by burning the litter taken from its corresponding microhabitat, and the other subsample was left unburned and used as a control. Fire intensity, determined by the fuel type, affected more markedly the native seedbank survival than the alien one. The low-intensity fire produced by grassland litter did not significantly affect the emergence of native herbs but increased alien species richness. The high-intensity and the very high-intensity fires produced by litter burning from beneath the canopy of the closed and the open matorral, respectively, negatively affected the seedling emergence of both native and alien species, but did so in a more pronounced manner to native species. Therefore, anthropogenic fires in central Chile may promote the invasion of alien plants with favourable traits (i.e. heat-shock resistance of seeds) that are not present in the native flora.