Berger-Parker Dominance Index Research Articles

Community Structure of Social Wasps (Hymenoptera: Vespidae) in Riparian Forest in Batayporã, Mato Grosso do Sul, Brazil

Reduction and destruction of riparian forests are harmful to the biota, especially the social wasps. This study analyzed the species constancy and the structure of the polistine wasp community associated with fragments of riparian forest in the municipality of Batayporã, state of Mato Grosso do Sul. Eighteen species of social wasps were collected, by the methods of active searching and traps baited with honey and sardine. Eight species were classified as infrequent, five as very frequent, and five as of intermediate frequency. The community structure, as represented by species richness, showed a significant negative correlation with the Berger-Parker dominance index, and no significant correlation with the width of the fragments and with the structural complexity of the vegetation, suggesting that the community, in this case, must be structured by the tolerance of the species and not by the vegetation characteristics, which did not limit the dispersal of the social wasps.

Floristic diversity of valonia oak silvopastoral woodlands in Greece

Valonia oak (Quercus ithaburensis subsp. macrolepis (Kotschy) Hedge and Yaltirik), a deciduous species grown in the xerothermic conditions of the east Mediterranean zone of Europe, forms woodlands of open canopy that permits adequate light to reach the ground thus sustaining an exceptionally rich flora. In Greece, these woodlands are mainly used for livestock grazing and considered important silvopastoral systems. Nowadays, most of them are abandoned and degraded as a result of inappropriate management. For the effective evaluation and sustainable management of these woodlands and the establishment of reliable monitoring systems, a detailed analysis of their plant diversity characteristics across Greece is needed. This paper aims at determining and comparing floristic diversity measures as well as at assessing the impact of human activities on vegetation and floristic diversity of the most characteristic valonia oak silvopastoral woodlands of Greece. It was found that the truncated log-normal model adequately predicts the species abundance data for eleven out of the twelve woodlands. From the statistical comparison of the diversity indices Q-statistic, Berger–Parker dominance index and Shannon-Wiener measure of equitability, three groups of these woodlands can be distinguished (a) the high-richness group of Pentalofos, Lesvos, Lakonia and Thesprotia, (b) the medium-richness group of Kriti Island, Alexandroupoli, Strofylia and Galaxidi, and (c) the low-richness group of Kea Island, Amfilohia, Almyros and Lilaia. However, the Renyi’s diversity ordering diagram showed that, generally, in low levels of entropy inconsistency is the rule and no clear pattern of diversity is extracted reflecting the impact of complex factors. Among them, those related to management seem to mostly determine plant diversity of valonia oak silvopastoral woodlands, with abiotic factors having an occasionally supporting role. Changes of species richness and evenness due to livestock grazing as well as acorn and wood harvesting are further discussed.

Metazoan endoparasites diversity of Pseudoplatystoma corruscans (Siluriformes: Pimelodidae) as an indicator of environmental alterations on a tropical aquatic system.

The aim of the present study was to detect the alterations of Pseudoplatystoma corruscans parasite infracommunity structure, after the construction of the Porto Primavera dam on the high Paraná River floodplain. The execution of this research was based on 119 host specimens collected between March 2011 and September 2012, and the results were compared to studies performed on periods before the reservoir's construction, when 110 fishes were collected between March 1992 and February 1993. Five parasite species still remain on the environment, despite the environmental modifications: Choanoscolex abscissus, Spasskyelina spinulifera, Nomimoscolex pertierrae, Harriscolex kaparari and Contracaecum sp 2. The Berger-Parker dominance index, calculated to the parasite fauna of 1992, did not show the dominance of any species, while, on the present days, this same index accused the dominance of Nomimoscolex pertierrae (49%) and Choanoscolex abscissus (50%). The present study reports the disappearance of Megathylacus travassosi, Contracaecum sp. 1, Contracaecum sp. 3, Procamallanus (Spirocamallanus) sp. and Cucullanus pseudoplatystomae, suggesting the possibility of a local extinction or a host switch of these species. It has also been registered an Acanthocephala specimen, a genus not observed on this host yet. The results here presented show that the antropic influences on natural systems alter the environmental conditions, what is reflected on the richness and diversity parasite levels.

Composición de la fauna de Araneae (Arachnida) de la Reserva provincial Iberá, Corrientes, Argentina

A survey of the spider community composition and diversity was carried out in grasslands and woods in three localities: Colonia Pellegrini, Paraje Galarza and Estancia Rinc6n (Iberá province Reserve). Pit fall traps, leaf litter sifting, foliage beating, hand collecting and sweep nets were used. Shannon's diversity index, evenness, Berger-Parker's dominance index, beta and gamma diversity were calculated, and a checklist of spider fauna was compiled. Species richness was estimated by Chao 1, Chao 2, first and second order Jack-knife. A total of 4,138 spiders grouped into 150 species from 33 families of Araneomorphae and two species from two families of Mygalomorphae were collected. Five species are new records for Argentina and eleven for Corrientes province. Araneidae was the most abundant family (39.8%), followed by Salticidae (10.9%), Anyphaenidae (7.9%), Tetragnathidae (7.4%), and Lycosidae (5.5%). The other families represented less than 5% of the total catch. The web-builder guild had the highest number of specimens and the highest richness index. The abundance, observed richness, Shannon diversity and evenness indexes were highest in Colonia Pellegrini woodland and Paraje Galarza grassland. Alpha diversity represented 89% of the gamma; the remaining 11% corresponded to beta diversity. According to the indexes, between 67% and 97% of the existing spider fauna was represented in the collected specimens from Iberá.

Phytoplankton Investigation and Environmental Assessment for Dredged Area in Daqing Estuary Section of Dianchi Lake, China

Daqing River is one of the major rivers flowing into the Dianchi Lake. In this paper, phytoplankton investigation and environmental assessment for the dredged area in Daqing Estuary Section of Dianchi lake in Kunming city was reported. After microscopic identification and counting of 6 water samples(two of them is control plot), the water environment were evaluated by the phytoplankton species and quantity which were assessed by the biological diversity index, including Maglarf, Shanon-Wiener, Simpson diversity index, Pielou index and Berger-Parker dominance index. It’s found that there are mainly 5 species of algae, and among them, Microcystis spp. et al., are the dominant species. So the water is assessed as eutrophication, Heavy sewage. Based on the diversity index analysis, the dredged area sampling sites were relatively higher than the non-dredged areas in biodiversity of phytoplankton. Summarily, the water quality after dredging has been improved to some extent. Phytoplankton biodiversity indicators should be the important water environmental assessment method.

Macrobenthic assemblage structure in a cool-temperate intertidal dwarf eelgrass bed in comparison with those from lower latitudes

The evolution and ecology of latitudinal patterns in marine macrofaunal biodiversity and assemblage structure are contentious. With the aim of investigating the occurrence of such patterns in intertidal dwarf eelgrass beds (Nanozosteraspp.), those at cool-temperate Scolt Head Island, UK (latitude 52°N), were examined and compared with equivalent systems in warm-temperate Knysna, South Africa (34°S), and subtropical Moreton Bay, Australia (27°S): systems that had earlier been examined using an identical methodology. The Scolt Head bed supported the highest faunal density (mean 6568 0.1m -2), lowest observed and estimated species richness (32 and 33 spp., respectively), lowest species diversity (Simpson's index of diversity 0.34), highest mean constancy index (23.0), lowest proportion of total numbers contributed by singletons or doubletons (0.06%), largest Berger-Parker dominance index (0.81), and least degree of variability between component samples. The beds at Knysna were intermediate between those at Scolt Head and at Moreton Bay in all those respects, as well as in nature and composition of the fauna. Similar dwarf eelgrass beds at Arcachon, France, likewise appear intermediate between those of Scolt Head and Knysna. Community variance in all three regions was greatest at the smallest spatial scale of ≤1m, at which scale two of the three sites also displayed randomly organized faunal assemblages, although this changed to non-random at larger spatial scales. Assemblages were deterministically structured at all spatial scales at Knysna. A consistent series of changes in structural characteristics of macrofaunal dwarf-eelgrass assemblages therefore occurred along the latitudinal sequence of Scolt Head (53°), Arcachon (45°), Knysna (34°), and Moreton Bay (27°). Community assembly patterns did not change with latitude, however, but did so with spatial scale in two of the three regions. © 2011 The Linnean Society of London.

Seasonality of Parasitic Copepods on Bullseye Puffer, Sphoeroides annulatus (Pisces: Tetraodontidae), From the Northwestern Coast of Mexico

Seasonal occurrence of parasitic copepods in wild bullseye puffer, Sphoeroides annulatus (Pisces: Tetraodontidae), was analyzed in conjunction with variation of biotic and abiotic factors. Eleven samples were taken between February 2007 and February 2008 in Santa María La Reforma lagoon (northwestern coast of México). In total, 337 fish was examined; 5 parasitic copepod species were observed, including Acantholochus zairae , Caligus serratus , Lepeophtheirus simplex , Pseudochondracanthus diceraus , and Parabrachiella sp. The most common species were L. simplex , P. diceraus, and C. serratus (overall prevalence, 59, 53, and 35%, respectively), which significantly varied in prevalence and mean intensity between sampling months. A seasonal pattern was only observed for L. simplex, with higher infection levels in the warmest month than in the coldest month. Statistical analyses indicated that the intensity of L. simplex was positively correlated with water temperature. There were no significant differences in prevalence and intensity of infection among female and male hosts. At the component community level, species richness ranged between 4 and 5 during most of the study period, and no seasonality was observed in the number of individuals, Shannon diversity index, evenness index, or the Berger-Parker dominance index. At the infracommunity level, 4 descriptors used (mean species richness, mean number of individuals, mean Brillouin's diversity index, and mean Berger-Parker index) varied significantly between sampling months, but no seasonality was observed, except for a slight increase in the number of individuals during the warmest month. A significant positive association was detected between number of individuals and water temperature and between host size and both species richness and number of individuals. This is the first account of the ecology of these 5 parasitic copepods. Although no significant association was detected between fish condition factor and the burden of parasitic copepods, given the high occurrence of the caligid copepod L. simplex , we suggest that this copepod could represent a threat for the culture of S. annulatus .

Dependence that the community structure of the roach Rutilus rutilus (L.) parasites has on the host age

The changes that take place in the structure of the parasite communities of two roach populations as the hosts grow older have been studied in the Chivyrkuiskii Bay of Lake Baikal and the estuary of the Selenga River. The parasite communities are analyzed at the levels of host individuals (infracommunities), host age groups (sets of infracommunities), and host population (component community). The number of parasite species regularly increases as the roaches age in both aquatic bodies, whereas the evenness of the parasite communities decreases. The Berger-Parker dominance index of the parasite communities changes with the roach age in different directions, increasing in the Chivyrkuiskii Bay and decreasing in the estuary of the Selenga River. The changes in the Shannon diversity index for sets of infracommunities of roach parasites are the opposite of those in the Berger-Parker index.

Seasonal distribution and species association among spider mites (Acari: Tetranychidae) and predatory mites (Acari: Phytoseiidae and Acari: Stigmaeidae) in Serbian apple orchards

ABSTRACT Species composition and population dynamics of spider mites (Panonychus ulmi (Acari: Tetranychidae) (Koch) and Tetranychus urticae Koch (Acari: Tetranychidae)) and predaceous mites (Amblyseius andersoni (Chant) (Acari: Phytoseiidae) and Zetzellia mali (Ewing) (Acari: Stigmaeidae)) were studied for eight months each year (March–October) during 2005–2007 at two localities with different intensities of pesticide use. Using Berger–Parker's dominance index and Sorenson's coefficient, the index of dominance and predator–predator, predator–prey, and prey–prey associations were defined among each of these species to determine changes in species compositions and population densities and comprehend the influence of pesticide use in pest management on populations of spider and predatory mites in apple orchards. Sorenson's coefficient helped to measure the intensity of positive, neutral, or negative interspecific associations for each species and Berger–Parker's dominance index clarified the dominance of specific species. During 2005 the dominant species in both localities was P. ulmi, but during 2006–2007 at one locality both species of spider mites showed almost equal dominance. The results of Sorenson's coefficient confirmed that there was significant predator–prey association among P. ulmi and A. andersoni and P. ulmi and Z. mali, and prey–prey association between P. ulmi and T. urticae in both localities. The analysis of the population dynamics showed delayed occurrence of predatory mites compared with the spider mites, from 48 to 106 days for A. andersoni and 91 to 137 days for Z. mali depending on the research period and locality.

Aquatic macrophytes and water current velocity in the Danube River

Water currents are among the strongest environmental variables determining the occurrence and/or abundance of aquatic plants and the European Water Framework Directive (WFD) considers river morphology and current conditions important aspects of reference conditions. We used the database of the Joint Danube Survey JDS-2, organised by the International Commission for the Protection of the Danube River (ICPDR, Vienna), to assess the relationship between water flow velocity and the occurrence and abundance of aquatic macrophyte to be species along the navigable reach of the Danube River. Species abundance was assessed in accordance with European Standard EN 14184-2003. Flow velocities were assessed close to the plant stands and estimated in 4 classes, worked out in earlier studies in combination with flow meter measurements, which is appropriate for the conditions in this large river. Statistical analysis revealed that only survey units with either no visible flow or those with fast flow were characterised by indicator species with high significance. Still water conditions or barely visible flow (flow class 1) were indicated by Potamogeton friesii, Nitellopsis obtusa and Trapa natans, and by Potamogeton perfoliatus, Potamogeton nodosus and Stuckenia pectinata. Lemna minor, indicative for flow class 1 as well, was detected in all the other flow classes, too: in all these cases it established its stands closely intermingled with other aquatic species. For survey units with slow (flow class 2) or intermediate flow (flow class 3). No statistically significant indicator species could be determined. The highest flow velocities (flow class 4) were significantly indicated by Fissidens rufulus, Cinclidotus fontinaloides and Cinclidotus riparius. Occurrence of aquatic mosses was also highly related to the Berger–Parker dominance index in NMDS analysis. In the same analysis, but towards the smallest flow velocities, the majority of vascular species and the Simpson diversity index were closely related. The spectrum of life forms was considerably reduced under medium and high flow velocity conditions. With regard to Simpson species diversity, our analysis indicates an agglomeration of diversity in the Middle Danube reach that includes the Iron Gates impoundment. Our results offer a first look at the macrophyte/water flow relationship of a very large river in Europe, the Danube.

Oribatid mite (Arachnida: Oribatida) coenoses from SW Sardinia

Oribatid mite communities were investigated at five sites in SW Sardinia (Carbonia-Iglesias and Medio Campidano provinces) in three representative habitat types: holm oak (Quercus ilex) forest, cork oak (Quercus suber) forest and pineland (Pinus radiata and P. pinaster). A total of 1,180 oribatid mite specimens, belonging to 67 different species, were extracted from soil samples. Significant differences in species diversity, abundance and Berger-Parker index of dominance were found among the different vegetation types throughout the sampling period, and non-metric multidimensional scaling (n-MDS) ordination confirmed a clear separation between the three coenoses, showing how oribatid assemblages are significantly affected by habitat evolution. The faunistic knowledge of the oribatid mites of Sardinia is rather poor, the present research represents one of the first contributions for the main Sardinian island. Besides a majority of eurytopic and widespread species representing the main part of the edaphic communities in Mediterranean landscapes, some rare and characteristic species are recorded. They are remnants of the original populations of Sardinia and the western part of the Italian peninsula, resulting from the complex tectonic events that formed the western Mediterranean basin. Among these, Belorchestes gebennicus Grandjean, 1957 (Zetorchestidae), Microppia minus longisetosa Subías & Rodriguez, 1988, and Pluritrichoppia insolita Subías & Arillo, 1989 (Oppiidae) had never been collected in Italy, single individuals of Oxyoppioides and Thamnacarus probably belong to undescribed species, while Brachychthonius hirtus Moritz, 1976 (Brachychthoniidae), Mongaillardia aeoliana (Bernini, 1979) (Amerobelbidae), Berniniella aeoliana (Bernini, 1973), Lauroppia similifallax Subías & Minguez, 1986, Ramusella (Ramusella) gyrata (Mahunka & Paoletti, 1984) (Oppiidae) and Ophidiotrichus oglasae Bernini, 1975 (Oribatellidae) are new to the Sardinian fauna.

Responses of Chironomid larvae (insecta, Diptera) to ecological quality in Mediterranean river mesohabitats (South Italy)

AbstractChironomid larvae and pupae were studied in selected Mediterranean rivers with the aim of identifying pool and riffle taxa assemblages and of analysing their response to ecological quality gradients. Macroinvertebrate samples were collected in six Italian rivers along a pool‐riffle sequence in three seasons following a multihabitat sampling technique. Chironomids were identified as genus/species, other macroinvertebrates as family/genus. The main physico‐chemical, hydromorphological and geographical data were collected. Samples were ascribed to five quality classes according to the STAR_ICM index. Based on Chironomid taxa, principal component analysis (PCA) axis 1 represented an organic pollution gradient, axis 2 represented seasonality. Pool and riffle samples were significantly different according to taxa assemblages. Similar results were obtained with PCA based on the whole macrobenthic community. Indicator value (IndVal) analysis facilitated the detection of the Chironomid indicators of high/good quality pools (e.g. Conchapelopia pallidula, Rheopelopia ornata, Epoicocladius ephemerae) and riffles (Tvetenia calvescens, Eukiefferiella gracei). The Berger–Parker dominance index based on Chironomid assemblages in pools was correlated to PCA axis 1 and performed well in discriminating between quality classes. In riffles, no correlations to PCA axes were detected and a wide overlap between quality classes was present. Thus, assessment in the analysed river type may focus on pool mesohabitat as this seems to represent best the ecological gradient of sites. Copyright © 2009 John Wiley & Sons, Ltd.

Salinity dependence of parasite infestation in the European eel Anguilla anguilla in northern Germany

Abstract Jakob, E., Hanel, R., Klimpel, S., and Zumholz, K. 2009. Salinity dependence of parasite infestation in the European eel Anguilla anguilla in northern Germany. – ICES Journal of Marine Science, 66: 358–366. The aim of the study was to examine metazoan parasite communities of European eels (Anguilla anguilla) in fresh-water, brackish water and marine localities in northern Germany. In all, 29 parasite species/taxa were found in 170 eels: eight digeneans, one monogenean, five cestodes, ten nematodes, two acanthocephalans, and three crustaceans. Measures of diversity characteristics of the helminth communities included species richness, Shannon's diversity index and its evenness, and the Berger–Parker dominance index. The highest species diversity and lowest dominance values were calculated for the helminth communities of eels from the two Baltic Sea localities. Parasite communities of European eels clearly exhibit the habitat preferences of their hosts, salinity-dependent specificities, and a clustering into fresh-water, brackish, and marine groups. The highly pathogenic parasite species Anguillicola crassus and Pseudodactylogyrus spp. were found at all sampling sites in fresh water and brackish water, with high prevalence. Basic information is provided on the risks of restocking programmes solely focusing on fresh-water sites.

Commercial harvest of logging residue in clear-cuts affects the diversity and community composition of ground beetles (Coleoptera: Carabidae)

Structural complexity of the habitat is known to influence the diversity and abundance of arthropod populations. Earlier studies have shown that presence of logging residue (slash) on the ground contributes to microhabitat complexity and removal of slash for biofuel in clear-cuts can have short-term (∼1 year) effects on ground-active beetle populations. This study examines the consequences of slash removal on carabids (Coleoptera: Carabidae) 5–7 years after harvest. Sampling of beetles was done by pitfall trapping in three matched clear-cut pairs, in spruce forest in central Sweden. The number and diversity (Berger–Parker dominance index) of carabid species were significantly higher in clear-cuts with slash harvest than in sites where slash was left on the ground. No difference in the overall rank-abundance pattern was found between clear-cuts with different slash treatments, but for species with certain habitat preferences the community was significantly altered. In all clear-cuts, slash removal caused a shift in dominance with an increase in generalist species and a decline in forest species. The results show that removal of slash may have long-lasting effects on the carabid community composition and structure. Hence, in forest landscapes with large-scale biofuel harvest, generalist carabid species may increase their abundance. Following the precautionary principle, it is suggested that every fifth clear-cut should be free of slash harvest.

Distribution patterns and interactions of cestodes in the spiral intestine of the narrownose smooth-hound shark, Mustelus schmitti Springer, 1939 (Chondrichthyes, Carcharhiniformes)

AbstractThe distribution patterns and the cestode species interactions within the spiral intestine of 20 specimens of Mustelus schmitti from coastal waters off Mar del Plata, Argentina were studied. Six cestode species were found: Tetraphyllideans Calliobothrium barbarae, C. australis, C. lunae and Orygmatobothrium schmittii, diphyllidean Echinobothrium notoguidoi and trypanorhynch Eutetrarhynchus vooremi. The most common number of parasite species per host was 3. Brillouin’s diversity index ranged from 0.1 to 1.2 Berger-Parker dominance index indicated that C. barbarae was the dominant species, followed by O. schmittii and C. australis. Calliobothrium barbarae, C. australis and O. schmittii presented a broad distribution along the spiral intestine, whereas C. lunae, E. notoguidoi and E. vooremi showed a more restricted niche breadth. In general, the Renkonen’s index showed no evidence of niche overlap in the range of distribution of the different species. In most of the infracommunities, intraspecific aggregation was stronger than interspecific aggregation, indicating that competition may play a little role. The distribution patterns of the Calliobothrium specimens concurs with the predictions of attachment sites for Calliobothrium species made by previous authors.

Flow permanence and macroinvertebrate community diversity within groundwater dominated headwater streams and springs

The response of aquatic macroinvertebrate communities to flow permanence within limestone springs and headwater streams was examined across the English Peak District. At the regional scale, macroinvertebrate communities of perennial and intermittent springs displayed significant differences in the number of taxa, macroinvertebrate community abundance, diversity indices (Shannon and Simpson indices) and the Berger–Parker dominance index at intermediate discharge. However, no significant difference was recorded between intermittent and perennial sites at high discharge or when all sampling occasions were pooled. At the catchment scale, the number of taxa, community abundance and Bray–Curtis similarity coefficients within the River Lathkill differed significantly between intermittent springs and other habitats. At both the regional and catchment scale the macroinvertebrate communities of intermittent springs were characterised by a small number of taxa displaying life cycle adaptations to intermittent aquatic habitats, particularly Trichoptera.

Medium-term temporal stability of the helminth component community structure in bank voles (Clethrionomys glareolus) from the Mazury Lake District region of Poland

The structure of helminth communities in wild rodents is subject to seasonal variation, and is dependent on host age within years. Although between-year variation has been monitored, seldom has it been assessed rigorously by appropriate multifactorial analysis with potentially confounding factors taken into account. In this study we tested the null hypothesis that despite seasonal, host age and sex effects, helminth communities should show relative stability between years. Over a period of 3 years (1998-2000) we sampled bank vole (Clethrionomys glareolus) populations (total n = 250) at 2 points in the year: in spring, at the start of the breeding season, and in autumn, after the cessation of breeding. In spite of seasonal differences and strong age effects, the between-year effects were surprisingly small. Measures of component community structure (Berger-Parker dominance index, the dominant species, S. petrusewiczi) did not vary, or varied only slightly from year to year. The majority of measures of infracommunity structure [Brillouin's index of diversity, prevalence of all helminths combined, prevalence and abundance of H. mixtum (the most prevalent helminth), mean species richness] did not differ significantly between years when other factors such as age, sex and seasonal variation had been taken into account. Some between-year variations were found (at the component community level, Simpson's index of diversity; at the infracommunity level, prevalence and abundance of S. petrusewiczi and abundance of all helminths combined), but even these were modest in comparison to seasonal and age differences, and were primarily attributable to S. petrusewiczi. We conclude that despite dynamic within-year fluctuations, helminth communities in bank voles in this region of Poland show relative stability across years. The sporadic occurrence of individual platyhelminths at low prevalence, makes little difference to the overall structure, which is largely maintained by the key roles played by the dominant intestinal nematodes of bank voles and the rarer species collectively.

The response of the macroinvertebrate community to low-flow variability and supra-seasonal drought within a groundwater dominated stream

Information regarding the instream response to long supra-seasonal droughts, extending over more than one season, in largely perennial riverine systems is fragmentary compared to knowledge regarding floods. The macroinvertebrate community of a groundwater dominated river was investigated over an eight-year period which included two supra-seasonal drought events (1992 and 1996-1997). The community responded directly to changes in the discharge regime. Significant differences in the community abundance, the abundance of the amphipod Gammarus pulex, diversity indices (Shannon Wiener and Simpson diversity) and the Berger-Parker dominance index were recorded between drought, flow recovery and other (non-drought) years. Drought conditions resulted in extremely low community abundance, Gammarus pulex abundance and the Berger-Parker dominance index, and extremely high values of the Shannon Wiener and Simpson diversity indices. Recovery of the community extended over a two-year period and reflected recovery of flow associated with recharge of the groundwater aquifer. The results underline the continuing need for medium to long-term data series to investigate the response of instream communities to flow variability so that extreme events can be placed within the context of natural variability.

Variation in the helminth community structure in spiny mice (Acomys dimidiatus) from four montane wadis in the St Katherine region of the Sinai Peninsula in Egypt.

We compared helminth communities in spiny mice (Acomys dimidiatus) from 4 wadis in the arid montane region of the southern Sinai in Egypt, in a 4-week period in late summer. Total helminth species richness was 14 (8 nematodes, 5 cestodes and 1 acanthocephalan) with 94% of mice carrying at least 1 species and an overall mean species richness of 1.85. The most prevalent parasites were Protospirura muricola (47.8 %) and Dentostomella kuntzi (46.3%). One larval cestode, Joyeuxiella rossicum, represents a new host record. The helminth community was dominated by intestinal nematodes (88.7%) of which 58.2% were arthropod-transmitted heteroxenic species. At the component community level, 70% of the worms were recovered from mice in just two wadis (Gharaba and Tlah) and 48.6 % of intestinal nematodes were from Wadi Gharaba. Although only 7 species of helminths were recorded from Wadi Gharaba, this site gave the highest Berger-Parker dominance index because of P. muricola. P. muricola was also dominant in Wadi El Arbaein whilst Syphacia minuta was the dominant species in Wadis Gebal and Tlah. At the infracommunity level, mean species richness and Brillouin's index of diversity were highest in Wadi Tlah and lowest in Wadi Gebal, and the former was age dependent. Whilst mice from different wadis differed in the nematodes that were most common, those from Wadi Gharaba carried the highest mean number of worms/mouse. The abundance of P. muricola in particular varied markedly between sites: Wadi Gharaba was distinct as the site showing the highest mean worm burden whereas mice from Wadi Gebal were uninfected. None of the directly transmitted oxyuroid nematodes showed significant variation in abundance between wadis, or host sex or age classes. Overall, the single extrinsic factor in the study, site of capture, was more important than the intrinsic factors in explaining variation in helminth communities in the region. We conclude that in the high mountains of southern Sinai, each wadi is distinct in terms of its rodent parasites, and hence we expect spatially different coevolutionary pressures on their hosts, with resultant variation in life-histories.

Diversity comparisons of beetles (Insecta: Coleoptera) between impact flight trap and ultraviolet light trap in the secondary forest at Kadoorie Farm, Hong Kong

Kadoorie Farm and Botanical Garden is located in the New Territories, on the mainland of Hong Kong. During 1990 - 1995 impact flight (IM) and ultraviolet light (UV) traps were set for several consecutive periods to study abundance, diversity, and phenology of the Class Insecta. We report here these features for the Order Coleoptera and some major beetle families, and compare variation in these features for beetles between IM and UV traps. About 13000 specimens were collected belonging to 45 families (subfamilies) and 231 species. About 25% of these families are recorded from Hong Kong for the first time: Alleculidae, Biphyllidae, Byrrhidae, Colydiidae, Corylophidae, Cryptophagidae, Hydroscaphidae, Lagriidae, Lathridiidae, Limnichidae, and Zopheridae. Most of the beetles collected in the secondary forest are woodborers both in number and kind (either xylophagous or saprophytophagous), in contrast with the majority of phytophagous beetles collected by sweep nets in a nature reserve across the border in nearby mainland China. The Margalef (1958) rich- ness index indicates that Mordellidae, Coccinellidae, Curculionidae, Cerambycidae, Chrysomelidae, Elateridae, Carabidae, Staphylinidae, Corylophidae, Buprestidae, Nitidulidae, Scolytidae, and Tenebri- onidae are the richest families in species in decreasing order (d1.5). The Shannon-Wiener (1949) diversity index indicates that Mordellidae, Coccinellidae, Curculionidae, Staphylinidae, Elateridae, Chrysomelidae, Cerambycidae, Carabidae, Nitidulidae, and Buprestidae are the most diverse families in decreasing order (H'1.5). The Pielou (1975) evenness index indicates that Mordellidae, Coccinelli- dae, Curculionidae, Staphylinidae, Elateridae, Chrysomelidae, and Cerambycidae are the most balanced families in diversity and abundance in decreasing order (J0.3). The Berger-Parker (1970) domi- nance index indicates that Scolytidae, Cerambycidae, Bostrichidae, Scarabaeidae, and Curculionidae are the most abundant families in number of individuals in decreasing order (D1.5%). Overall, Ceram- bycidae, Coccinellidae, Curculionidae, Mordellidae, Scarabaeidae, and Scolytidae are the major families in the secondary forest with number of species≥15 or number of individuals≥200. Over 85% of all specimens were bark beetles during the study period, suggesting an outbreak of Scolytidae in the seconda- ry forest. Seasonal patterns of the Coleoptera are conspicuous. Abundance of beetles began to increase in Feb- ruary and drastically decreased in August, but peak occurrence differed between IM and UV traps. Those caught by UV had a distinct peak in June, while those caught by IM peaked in July. Beetles in each of the major families also showed different seasonal patterns of abundance. Families with one single species comprise over 50% of the beetle families. Captures by different traps are often mutually exclusive. About 30% of the beetle families were caught by only IM traps, while 10% were caught by only UV traps. Of the remaining 26 families, 11 had at least one species that was mutually exclusively captured by different traps. In total, 65% of the 45 families contained species trapped by one method but not by the other. Scolytidae had the greatest abundance in both IM and UV traps. Mordellidae had the highest species diversity in IM traps, while Coccinellidae had the highest spe- cies diversity in UV traps based on the richness, diversity, and evenness indices. The value (1.67) of the Shannon-Wiener index for the order Coleoptera is within the normal range, but lower than the neigh- boring area where beetle specimens were collected by sweep nets. IM captures overwhelmingly outnumbered UV captures. This could be the result of more IM traps and longer operating periods than UV traps. However, the values of the Shannon-Wiener diversity and Pielou evenness indices are about 85% and 120% higher for UV than IM traps, respectively. This indi- cates that it is important to use different trapping methods in a bio