Microhabitat Types Research Articles

The forgotten tigers: the arboreal tiger beetles of Sri Lanka

Thirty-one species of arboreal tiger beetles are known to occur in Sri Lanka of which twenty-five species are stated to be endemic. However, the group has not been studied for more than a century and the last organised records are provided by Fowler (1912) in his studies of the ‘Fauna of British India including Ceylon and Burma (Coleoptera General Introduction and Cicindelidae and Paussidae)’. Due to high endemicity rates, biodiversity value and current disturbances and destruction to natural forests of the country, which are the main habitat types of the arboreal tiger beetles, it is important that this insect group be thoroughly studied. Therefore, a study was initiated on the ‘Diversity, distribution and habitat types of arboreal tiger beetles (Coleoptera, Cicindelinae) of Sri Lanka’, funded by the National Science Foundation of Sri Lanka. This review compiles and records previous information on the arboreal tiger beetles of Sri Lanka, which will provide a foundation for future studies and reveal gaps in the knowledge of this insect group. The review discusses: 1) taxonomy of the arboreal tiger beetles, highlighting the genera found in Sri Lanka and their affinities to arboreal tiger beetle genera elsewhere in the world; 2) previous locations and distribution of species throughout the island and districts and provinces from which species are not recorded, habitat and micro-habitat types; 3) morphological characters of genera and species and unique characters used for the separation of species, life-cycle strategies; and 4) methods employed to collect arboreal tiger beetle species and threats to the survival of this insect group.

Searching for the Immature Stages of Ixodes scapularis (Acari: Ixodidae) in Leaf Litter and Soil in Texas.

The standard tick collection methods of flagging and dragging are successful for collecting all stages of the blacklegged tick, Ixodes scapularis (Say) (Acari: Ixodidae), in the northern United States. However, for unknown reasons, these methods are unsuccessful for collecting the immature stages of I. scapularis in the southern United States. Thus, a different collection strategy was employed to search for the immature stages of I. scapularis in the southern state of Texas. Monthly sampling of three types of microhabitats potentially harboring ticks was conducted for 17 mo at the Big Thicket National Preserve. Samples of leaf litter, topsoil, and subsoil were placed within Berlese funnels to determine if the immature stages of I. scapularis are residing in these layers. No ticks were found in any of the 600 substrate samples examined. Along nearby trail edges in the same area, 656 adult I. scapularis (an average of 22.6 per 1,000 m2), as well as 268 immatures of other species (i.e., Amblyomma americanum (Linnaeaus) (Acari: Ixodidae) and Dermacentor variabilis (Say) (Acari: Ixodidae)) were collected using flagging and dragging. These results suggest that unlike speculations from previous studies in the southern United States, the immature stages of I. scapularis may not be residing in the leaf litter and soil layers in Texas. We hypothesize that they may be residing in their host's nests and burrows. Perhaps I. scapularis in the south is exhibiting a stage specific mixed host-seeking strategy by residing in nests and burrows as immatures, contributing to the geographical difference in Lyme disease prevalence between the northern and southern United States.

Behavioral differences following ingestion of large meals and consequences for management of a harmful invasive snake: A field experiment.

Many snakes are uniquely adapted to ingest large prey at infrequent intervals. Digestion of large prey is metabolically and aerobically costly, and large prey boluses can impair snake locomotion, increasing vulnerability to predation. Cessation of foraging and use of refugia with microclimates facilitating digestion are expected to be strategies employed by free‐ranging snakes to cope with the demands of digestion while minimizing risk of predation. However, empirical observations of such submergent behavior from field experiments are limited. The brown treesnake (Serpentes: Colubridae: Boiga irregularis) is a nocturnal, arboreal, colubrid snake that was accidentally introduced to the island of Guam, with ecologically and economically costly consequences. Because tools for brown treesnake damage prevention generally rely on snakes being visible or responding to lures or baits while foraging, cessation of foraging activities after feeding would complicate management. We sought to characterize differences in brown treesnake activity, movement, habitat use, and detectability following feeding of large meals (rodents 33% of the snake's unfed body mass) via radio telemetry, trapping, and visual surveys. Compared to unfed snakes, snakes in the feeding treatment group showed drastic decreases in hourly and nightly activity rates, differences in refuge height and microhabitat type, and a marked decrease in detectability by trapping and visual surveys. Depression of activity lasted approximately 5–7 days, a period that corresponds to previous studies of brown treesnake digestion and cycles of detectability. Our results indicate that management strategies for invasive brown treesnakes need to account for cycles of unavailability and underscore the importance of preventing spread of brown treesnakes to new environments where large prey are abundant and periods of cryptic behavior are likely to be frequent. Characterization of postfeeding behavior changes provides a richer understanding of snake ecology and foraging models for species that consume large prey.

Environmental drivers influencing stonefly assemblages along a longitudinal gradient in karst lotic habitats

Stoneflies are among the most sensitive aquatic insect taxa and therefore arguably the best indicator of the excellent, i.e. pristine, ecological status of surface streams. Karst habitats are one of the most exciting freshwater habitats in terms of biological-geological interplay. They, in turn, support a biodiversity far superior to surrounding freshwater habitats and hence these habitats are designated as biodiversity hotspots. Our study deals with both of these crucial ecological players. We studied stonefly assemblages, their microhabitat preferences and emergence patterns along a karst oligotrophic hydrosystem. The sampling was conducted monthly from March 2007 to December 2008 using pyramid-type emergence traps set in various habitats and associated microhabitats (e.g. springs, rivers, streams, tufa barriers × moss, angiosperm, cobble, sand, silt substrates). Favorable environmental conditions, such as a wide range of karst habitat types with low water temperature and high oxygen concentration, resulted in high stonefly species richness (31 recorded species). Water temperature and pH had the highest influence on stonefly assemblages. Species richness and diversity decreased in a downstream direction. We recorded a longitudinal shift from crenal-epirhithral to epirhithral-metarhithral assemblages with some hyporhithral and potamal elements. Upstream sites were dominated by shredders, while downstream sites had a higher proportion of gatherers-collectors. Several species showed a significant preference for a specific microhabitat type in accordance with their feeding strategies and food availability. The majority of recorded species exhibited univoltine life cycles slow or fast.

The Dispersal Effectiveness of Avian Species in Japanese Temperate Forest

Seed dispersal effectiveness (SDE) is one of the best parameters for estimating the benefit that a plant obtains from a dispersal agent. SDE includes quantitative and qualitative components. Previous avian studies of SDE estimation have been conducted mainly in temperate shrub lands or in tropical forests; data are limited for temperate forests, especially, the quality of seed-deposition sites. In this study, we estimated the SDE of birds for Wild Cherry Cerasus jamasakura and Giant Dogwood Cornus controversa fruits in a temperate Japanese forest. These trees prefer sunny sites so we focused on the light conditions at seed-deposition sites and categorized three microhabitat types: forest-gap, forest-edge, and forest-interior. We observed avian seed removal at fruiting trees, conducted a bird census to estimate microhabitat selectivity and collected bird-dispersed seeds. We then counted seedling emergence. Finally, we constructed generalized linear mixed models that combined bird census and dispersed seed data to identify influential seed disperser(s) for each tree species. Frugivorous behavior was recorded for eight avian species for C. jamasakura and 12 for C. controversa. Of these birds, one for the former, and two for the latter preferentially selected forest-gap or forest-edge trees during each fruiting period. The density of dispersed seeds and seedlings was higher in the forest-gap or forest-edge. Additionally, the frequency with which Japanese White-eye Zosterops japonicus visited was a significant variable for seed density in each microhabitat. The results suggested that microhabitat selectivity may affect the density of dispersed seeds in each microhabitat. Furthermore, a bird with a high quantitative SDE may not necessarily also have a high qualitative SDE. Thus, it is important to estimate qualitative and quantitative SDE by focusing especially on the seed-deposition site for each bird in order to evaluate the actual SDE in temperate forests.

Diversity and abundance of conspicuous macrocrustaceans on coral reefs differing in level of degradation.

Coral reefs sustain abundant and diverse macrocrustaceans that perform multiple ecological roles, but coral reefs are undergoing massive degradation that may be driving changes in the species composition and abundance of reef-associated macrocrustaceans. To provide insight into this issue, we used non-destructive visual census techniques to compare the diversity and abundance of conspicuous macrocrustaceans (i.e., those >1 cm and visible without disturbance) between two shallow Caribbean coral reefs similar in size (∼1.5 km in length) and close to each other, but one (“Limones”) characterized by extensive stands of the branching coral Acropora palmata, and the other (“Bonanza”) dominated by macroalgae and relic coral skeletons and rubble (i.e., degraded). We also assessed the structural complexity of each reef and the percent cover of various benthic community components. Given the type of growth of A. palmata, we expected to find a greater structural complexity, a higher cover of live coral, and a lower cover of macroalgae on Limones, and hence a more diverse and abundant macrocrustacean community on this reef compared with Bonanza. Overall, we identified 63 macrocrustacean species (61 Decapoda and two Stomatopoda). Contrary to our expectations, structural complexity did not differ significantly between the back-reef zones of these reefs but varied more broadly on Limones, and the diversity and abundance of macrocrustaceans were higher on Bonanza than on Limones despite live coral cover being higher on Limones and macroalgal cover higher on Bonanza. However, the use of various types of microhabitats by macrocrustaceans differed substantially between reefs. On both reefs, the dominant species were the clinging crab Mithraculus coryphe and the hermit crab Calcinus tibicen, but the former was more abundant on Bonanza and the latter on Limones. M. coryphe occupied a diverse array of microhabitats but mostly coral rubble and relic skeletons, whereas C. tibicen was often, but not always, found associated with colonies of Millepora spp. A small commensal crab of A. palmata, Domecia acanthophora, was far more abundant on Limones, emerging as the main discriminant species between reefs. Our results suggest that local diversity and abundance of reef-associated macrocrustaceans are partially modulated by habitat degradation, the diversity of microhabitat types, and the establishment of different commensal associations rather than by structural complexity alone.

Alderfly assemblages (Megaloptera, Sialidae) along an oligotrophic karst hydrosystem: spatial patterns and species-environment relationship

Even though alderflies, as well as many other aquatic macroinvertebrates, are widely used as indicators of freshwater quality, the knowledge of their distribution, biology and ecology in karst freshwater habitats is still very scarce. Aiming to fill this gap, we investigated alderfly assemblages along an oligotrophic karst hydrosystem. Sampling was carried out on a monthly basis over a one-year period (2007/2008) in different types of freshwater habitats and microhabitats. Our goals were to determine population aspects, habitat and microhabitat preferences of alderflies as well as their relation to environmental factors. Due to the specificity of karst freshwater habitats, alderflies were rather rare in the studied hydrosystem. Yet, their fauna was diverse with four identified species, where Sialis fuliginosa Pictet, 1836 was the most widespread one. Sialis sordida (Klingstedt, 1932) was recorded for the first time in the Balkan Peninsula being the rarest species in our study. Substrate type and water velocity showed as key environmental parameters in determining alderfly assemblages. Alderflies were mostly recorded from a canyon type mountainous stream, and silt with leaf litter, respectively. They were not recorded at sites characterized by predominately solid stones (i.e. cobbles) and mosses, and with intermittent water flow. Our results strongly indicate that alderflies could be used in future conservation and protection management procedures in karst freshwater habitats.

Species and Microhabitat of Crabs in Lantangpeo Mangrove Tanakeke Islands South Sulawesi

Research about crabs species (brachyura) in Lantangpeo, Tanakeke Islands, South Sulawesi has been conducted. The aim of this research was to know the crabs species on different type of mangrove microhabitat. Crabs collected with purposive sampling method in mangrove forest around the coastline, tidal creek, fish pond and sheltered waters between Lantangpeo island and Tanakeke island. From sampling activities there were found 28 species of crabs from 13 families. The number of crabs species in mangrove forest around the coastline were higher compared to another type of microhabitat. On the contrary, converted mangrove area (fish pond) were only supported least crabs species. It can be concluded that microhabitat in mangrove forest around the coastline supported more crabs species.

Nest site selection repeatability of green turtles, Chelonia mydas, and consequences for offspring

Nest site selection is a critical behaviour, particularly in species with no parental care, as it can greatly impact offspring survival. Marine turtles depend on sandy beaches to nest, where they select from a range of microhabitats that may differently affect hatchling survival and phenotype. Here we describe the degree of nest site selection at one of the largest green turtle rookeries globally, in Guinea-Bissau, West Africa, and how this impacts offspring. In 2013 and 2014 we recorded the spatial distribution of 1559 nests, and monitored 657 females during oviposition, to assess population and individual preferences on nesting site. Overall, females tended to nest close to the vegetation, at a preferred elevation of 4.8–5.0 m, which was above the highest spring tide (4.7 m), enhancing clutch survival. Individuals displayed high repeatability in nesting microhabitat type (open sand, forest border and forest), distance along the beach, distance to the vegetation and elevation, which may result from this behaviour having a genetic basis or from fine-scale nest site philopatry. Hatchlings from cooler nests were larger, potentially dispersing faster and more able to evade predators, while smaller hatchlings, from warmer nests, retained more energetic reserves (residual yolk), which may also be advantageous for initial dispersal, particularly if food is scarce. Thus, individual preferences in nest site selection led to trade-offs in offspring phenotype, but overall, most nesting females selected sites that increased offspring survival, suggesting that nest site selection is an adaptive trait that has been under selection. As under future climate change scenarios females nesting in upper shaded areas should have higher fitness, individual consistency in nesting microhabitat provides opportunity for natural selection to occur.

Micro-habitat distribution drives patch quality for sub-tropical rocky plateau amphibians in the northern Western Ghats, India.

The importance of patch quality for amphibians is frequently overlooked in distribution models. Here we demonstrate that it is highly important for the persistence of endemic and endangered amphibians found in the threatened and fragile ecosystems that are the rocky plateaus in Western Maharashtra, India. These plateaus are ferricretes of laterite and characterise the northern section of the Western Ghats/Sri Lanka Biodiversity Hotspot, the eighth most important global hotspot and one of the three most threatened by population growth. We present statistically supported habitat associations for endangered and data-deficient Indian amphibians, demonstrating significant relationships between individual species and their microhabitats. Data were collected during early monsoon across two seasons. Twenty-one amphibian taxa were identified from 14 lateritic plateaus between 67 and 1179m above sea level. Twelve of the study taxa had significant associations with microhabitats using a stepwise analysis of the AICc subroutine (distLM, Primer-e, v7). Generalist taxa were associated with increased numbers of microhabitat types. Non-significant associations are reported for the remaining 9 taxa. Microhabitat distribution was spatially structured and driven by climate and human activity. Woody plants were associated with 44% of high-elevation taxa. Of the 8 low-elevation taxa 63% related to water bodies and 60% of those were associated with pools. Rock size and abundance were important for 33% of high elevation specialists. Three of the 4 caecilians were associated with rocks in addition to soil and stream presence. We conclude the plateaus are individualistic patches whose habitat quality is defined by their microhabitats within climatic zones.

HABITAT CHOICE BEHAVIOR IN Macrobrachium brasiliense (HELLER, 1862) (DECAPODA, PALAEMONIDAE) UNDER LABORATORY CONDITIONS

The main objective of this study was to analyze the behavior of adult individuals of Macrobrachium brasiliense and their preferences regarding different substrates and microhabitats. The study comprised two distinct experiments; selection of substrates (1) and microhabitats (2). The first one was performed using three samples of substrates with different granulometries: fine sand, coarse sand and gravel. After, the microhabitat selection experiments were carried out using three types of microhabitats: algae, fragments of wood and rocks. There was a significant difference in males substrate preference (ANOVA, p 0.05). Regarding microhabitats, only algae were not selected by males (ANOVA, p <0.01), whereas females chose only the microhabitat composed of wood fragment (ANOVA, p <0.01). Based on these results, the existence of a differential behavior between the sexes for selection of substrates and microhabitats, suggesting that these animals can inhabit different places in the same environment, since in the laboratory a differentiation in their choices was observed.

Testing the potential mechanisms for the maintenance of a genetic color polymorphism in bluefin killifish populations.

The maintenance of genetic variation in the face of natural selection is a long-standing question in evolutionary biology. In the bluefin killifish Lucania goodei, male coloration is polymorphic. Males can produce either red or yellow coloration in their anal fins, and both color morphs are present in all springs. These 2 morphs are heritable and how they are maintained in nature is unknown. Here, we tested 2 mechanisms for the maintenance of the red/yellow color morphs. Negative frequency-dependent mating success predicts that rare males have a mating advantage over common males. Spatial variation in fitness predicts that different color morphs have an advantage in different microhabitat types. Using a breeding experiment, we tested these hypotheses by creating populations with different ratios of red to yellow males (5 red:1 yellow; 1 red:5 yellow) and determining male mating success on shallow and deep spawning substrates. We found no evidence of negative frequency-dependent mating success. Common morphs tended to have higher mating success, and this was particularly so on shallow spawning substrates. However, on deep substrates, red males enjoyed higher mating success than yellow males, particularly so when red males were rare. However, yellow males did not have an advantage at either depth nor when rare. We suggest that preference for red males is expressed in deeper water, possibly due to alterations in the lighting environment. Finally, male pigment levels were correlated with one another and predicted male mating success. Hence, pigmentation plays an important role in male mating success.

A comparative hierarchical analysis of bacterioplankton and biofilm metacommunity structure in an interconnected pond system.

It is unknown whether bacterioplankton and biofilm communities are structured by the same ecological processes, and whether they influence each other through continuous dispersal (known as mass effects). Using a hierarchical sampling approach we compared the relative importance of ecological processes structuring the dominant fraction (relative abundance ≥0.1%) of bacterioplankton and biofilm communities from three microhabitats (open water, Nuphar and Phragmites sites) at within- and among-pond scale in a set of 14 interconnected shallow ponds. Our results demonstrate that while bacterioplankton and biofilm communities are highly distinct, a similar hierarchy of ecological processes is acting on them. For both community types, most variation in community composition was determined by pond identity and environmental variables, with no effect of space. The highest β-diversity within each community type was observed among ponds, while microhabitat type (Nuphar, Phragmites, open water) significantly influenced biofilm communities but not bacterioplankton. Mass effects among bacterioplankton and biofilm communities were not detected, as suggested by the absence of within-site covariation of biofilm and bacterioplankton communities. Both biofilm and plankton communities were thus highly structured by environmental factors (i.e., species sorting), with among-lake variation being more important than within-lake variation, whereas dispersal limitation and mass effects were not observed.

Parasite-mediated microhabitat segregation between congeneric hosts.

Parasite-mediated competition can shape community structure and host distribution. If two species compete for resources, parasites may indirectly change the outcome of competition. We tested the role of a trematode parasite in mediating microhabitat use by congeneric isopods Austridotea annectens and Austridotea lacustris Although both isopods share resources, they rarely co-occur in the same discrete microhabitats. We set up mesocosms with and without competition and/or parasites to examine the role of parasites in host distribution and habitat segregation. Austridotea annectens showed a clear preference for one microhabitat type regardless of competition or parasitic infection. By contrast, A. lacustris showed little habitat selection in the absence of competition, but favoured sandy habitats in the presence of uninfected A. annectens and rocky habitats when competing with infected A. annectens Our results suggest that parasites in one species affect the distribution of another species, and mediate competition between these species. We demonstrated the impacts of a parasite on the microhabitat use of its host's competitor. This also represents an example of a super-extended phenotype, where a parasite affects the phenotype of a non-host.

The relative importance of regional, local, and evolutionary factors structuring cryptobenthic coral-reef assemblages

Factors shaping coral-reef fish species assemblages can operate over a wide range of spatial scales (local versus regional) and across both proximate and evolutionary time. Niche theory and neutral theory provide frameworks for testing assumptions and generating insights about the importance of local versus regional processes. Niche theory postulates that species assemblages are an outcome of evolutionary processes at regional scales followed by local-scale interactions, whereas neutral theory presumes that species assemblages are formed by largely random processes drawing from regional species pools. Indo-Pacific cryptobenthic coral-reef fishes are highly evolved, ecologically diverse, temporally responsive, and situated on a natural longitudinal diversity gradient, making them an ideal group for testing predictions from niche and neutral theories and effects of regional and local processes on species assemblages. Using a combination of ecological metrics (fish density, diversity, assemblage composition) and evolutionary analyses (testing for phylogenetic niche conservatism), we demonstrate that the structure of cryptobenthic fish assemblages can be explained by a mixture of regional factors, such as the size of regional species pools and broad-scale barriers to gene flow/drivers of speciation, coupled with local-scale factors, such as the relative abundance of specific microhabitat types. Furthermore, species of cryptobenthic fishes have distinct microhabitat associations that drive significant differences in assemblage community structure between microhabitat types, and these distinct microhabitat associations are phylogenetically conserved over evolutionary timescales. The implied differential fitness of cryptobenthic fishes across varied microhabitats and the conserved nature of their ecology are consistent with predictions from niche theory. Neutral theory predictions may still hold true for early life-history stages, where stochastic factors may be more important in explaining recruitment. Overall, through integration of ecological and evolutionary techniques, and using multiple spatial scales, our study offers a unique perspective on factors determining coral-reef fish assemblages.

Uso de microhábitats, actividad diaria y dieta de Dendrobates truncatus (cope, 1861) (Anura: Dendrobatidae) en bosque seco tropical del norte de Colombia

Se estudió el uso de microhábitats, actividad diaria y dieta de tres poblaciones de Dendrobates truncatus en el bosque seco tropical de tierras bajas del Caribe colombiano, mediante la utilización del método de encuentro visual y captura manual. El estudio se realizó entre los meses de marzo y noviembre, durante los tres períodos climáticos del año: seco, lluvias menores y lluvias mayores. Se identificaron y muestrearon siete microhábitats usados por esta especie, la actividad se midió a través de la relación número de individuos/hora en cuatro horarios diarios. Se examinaron los contenidos estomacales de los anuros y se aplicó el método de análisis porcentual. D. truncatus presenta mayor actividad en la mañana (8:00 – 10:00) y final de la tarde (16:00 – 18:00) y usa siete tipos de microhábitats, preferentemente los de cobertura boscosa y con altos valores de humedad. Presenta preferencia marcada por el consumo de hormigas, especialmente la familia Myrmicinae y el género Pheidole. Estos resultados sugieren que la conservación de relictos de bosque seco tropical y el desarrollo de estrategias de rehabilitación del mismo se constituyen en elementos fundamentales para la supervivencia de esta especie.

Microhabitat selection and distribution of functional feeding groups of mayfly larvae (Ephemeroptera) in lotic karst habitats

Research examining mayfly ecology in karst streams and rivers has increased in recent years, though microhabitat preferences remain poorly characterized. We examined mayfly assemblage taxonomy, functional feeding groups and microhabitat preferences in two contrasting lotic Dinaric karst catchments, one pristine and one anthropogenically impacted. At monthly intervals over a one-year period, all major microhabitats (i.e.dominated by boulders, cobbles, sand, silt, mosses, or angiosperms) were sampled at sites spanning springs, upper, middle and lower river reaches, and tufa barriers. In both catchments, mayfly species richness was comparable among microhabitats, while mayfly abundance was highest on mosses and lowest on silt. NMDS ordination did not group assemblages according to microhabitat type, which may reflect the greater influence of physical and chemical water properties. In both catchments and all microhabitats, mayfly assemblages were dominated by grazers/scrapers at upstream sites and by detritivores at downstream sites. Active filter feeders were more abundant in microhabitats with silt substrates and lower current velocities. This study demonstrated that certain mayfly species strongly preferred a specific microhabitat type, reflecting their water current preferences and feeding strategies, while other species shifted between microhabitats, likely in search of food resources and shelter. The results emphasize the importance of habitat heterogeneity in supporting diverse communities in karst rivers.

STUDY ON MACROZOOBENTHOS COMMUNITY IN THE WATERS OF THE RIVER AIR PERIKAN MUNICIPALITY OF PAGAR ALAM SOUTH SUMATRA

The research entitled “ Study on Macrozoobenthos Community in the Waters of the River Air Perikan Pagar Alam Municipality”, was conducted from November 2007 until March 2008. The aims of the research: to know about composition, density, diversity index, dominancy index, and similarity index, which based on the different microhabitat types. Sampling was carried out on November 2007. Five sampling stations were determined by survey method and the Purposive Sampling method was used at each sampling point to find stony, gravel, sandy and leaf pack area as a different microhabitat substrate. Twenty one orders (Ephemeroptera, Trichoptera, Diptera, Plecoptera, Collembola, Hemiptera, Odonata, Coleoptera, Lepidoptera, Megaloptera, Hymenoptera, Orthoptera, Decapoda, Plesiopora, Tricladida, Amphipoda, Isopoda, Mesogastropoda, Ctenobranchiata, Eulamellibranchiata, and Rhynchobdellida) which are consisted of 70 families and 151 genera were identified from four types of substrates on each sampling station. According to this research, station 4 has the highest in composition (80 genera), and the lowest one at station 1(33 genera). The highest abundance was 12589 ind./m2 found in the station 5, and the lowest one was in the station 1 approximately 880 ind./m2. For the diversity index value, station 3 was the highest (3.1) and the lowest one was station 5 (1.9). The Dominancy index was found in station 5 at the sandy substrates was approximately 0,8 index, which dominated by Tubifex sp. There were differences species composition on each station. Keywords : Macrozoobenthos, community, the river Air Perikan.

Different microhabitats have contrasting effects on the spatial distribution of tree regeneration density and diversity

Spatial distribution of tree recruitment has been shown to be largely affected by microhabitats. If we are to preserve the distribution and abundance of tree regeneration in the face of environmental changes, we need to consider the microhabitats characterizing their recruitment process. We investigated the effect of type of microhabitat on the regeneration distribution of four tree species presence in the Zagros forests of western Iran. Regeneration density and diversity were found to be highly dependent on microhabitat. Regeneration density of Quercus brantii and Ceracus microcarpa was higher in heterospecific microhabitats. The highest density of regeneration occurred in the Crataegus pontica microhabitat, which covered 10.5% of the area. This study found that specific microhabitats affected the spatial patterns of tree regeneration in Zagros forests. Recruitment was restricted to those microhabitats under which environmental conditions constituted safe sites for regeneration. The Crataegus pontica microhabitat seems to have a major role in providing a safe site for regeneration in these forests. We suggest focusing restoration actions in Crataegus pontica microhabitats to better facilitate tree regeneration.

Partitioning thermal habitat on a vertical rock, a herculean task

Species occurring in sympatry have to effectively segregate their niche in order to co-exist. In the case of ectotherms in particular, the very important parameter of thermal biology has to be taken into account. Here we investigated the thermoregulatory effectiveness (E) of two endemic Greek lizards (Hellenolacerta graeca and Podarcis peloponnesiacus) that live syntopically on a rocky cliff in the Peloponnese. We presumed that the two species would select different microhabitats, to avoid interspecific competition, and follow a similar thermoregulation pattern as they experience the same conditions. We also expected that E values for both species would differ depending on the season. Overall, we found that the two species had similar E values for each season but differentiated partial thermoregulatory attributes. Though they both occurred in the same types of microhabitat, H. graeca selected higher sites (average 99cm above ground) than P. peloponnesiacus (average 44cm). Also, the latter achieved higher preferred temperatures during summer and winter. Finally, the effectiveness of thermoregulation for both species varied interseasonally and received its highest values during summer, in response to the lowest thermal quality that was observed then. Similar studies stress the importance of thermal shifts for ectotherm co-existence.