Soil ciliate species richness and abundance associated with the rhizosphere of different subtropical plant species

Soil protozoa, and ciliates in particular, represent a microbial group abundant in the rhizosphere with an influential role on nutrient cycling. Under laboratory conditions, ciliates regulate the size and the composition of bacterial communities, and appear to stimulate ammonification and nitrification. In spite of their important ecological role, our understanding about the factors that control their diversity and abundance in natural forest ecosystems is still rudimentary. Plant species-specific interactions have been demonstrated between plants and soil bacteria and mycorrhizal fungi, due in part to the release of phytohormones and C- and N-rich exudates. We tested the hypothesis that the rhizosphere environments of different plant species also influence the species richness and abundance of soil ciliates. Plant effect, soil pH, moisture content, microbial biomass C, and inorganic nitrogen were measured among five plant species to determine the best predictor variables for soil ciliate species richness and total abundance in a subtropical moist forest in Puerto Rico. Based on an analysis of variance, we rejected the hypothesis that there was a plant species-specific effect on soil ciliates, unlike other microbial groups mentioned above. Using multiple regression analysis, we demonstrated that the flush of total inorganic nitrogen was the best predictor variable for both species richness and abundance of ciliates.     

A preliminary assessment of biofouling and non-indigenous marine species associated with commercial slow-moving vessels arriving in New Zealand

Vessel traffic is the primary pathway for non-indigenous marine species introductions to New Zealand, with hull fouling recognised as being an important mechanism. This article describes hull fouling on seven slow-moving commercial vessels sampled over a 1 year period. Sampling involved the collection of images and fouling specimens from different hull locations using a standardised protocol developed to assess vessel biofouling in New Zealand. A total of 29 taxa was identified by expert taxonomists, of which 24% were indigenous to New Zealand and 17% non-indigenous. No first records to New Zealand were reported, however 59% of species were classified as ‘unknown’ due to insufficient taxonomic resolution. The extent of fouling was low compared to that described for other slow-movers. Fouling cover, biomass and richness were on average 17.1% (SE = 1.8%), 5.2 g (SE = 1.1 g) and 0.8 (SE = 0.07) per photoquadrat (200 × 200 mm), respectively. The fouling extent was lowest on the main hull areas where the antifouling paint was in good condition. In contrast, highest levels of fouling were associated with dry-docking support strips and other niche areas of the hull where the paint condition was poor. Future studies should target vessels from a broader range of bioregions, including vessels that remain idle for extended periods (ie months) between voyages, to increase understanding of the biosecurity risks posed by international commercial slow-movers.     

Species richness and species composition of fungal communities associated with cellulose decomposition at different altitudes on the Tibetan Plateau

Aims The aims of this study were to compare the fungal communities developing on cotton strips at three different altitudes on the Tibetan Plateau and to assess the environmental variables influencing them.Methods Cotton strips that had been buried in soil for a year were sampled at three sites at different altitudes (4500, 4950 and 5200 m) located on a southeast-facing slope on the Nyainqentanglha Mountains near Damxung. The fungi on the cotton strips were isolated using a modified washing method. The decomposition abilities and colony growth properties of the major species cultured in pure-culture conditions were investigated and compared. Canonical correspondence analysis (CCA) was used to evaluate the relationships between fungal community composition and environmental variables (altitude, soil depth, soil water content [SWC], plant root mass and gravel content).Important findings A total of 24 species were isolated from the cotton strips, and 12 species occurred frequently and were regarded as major species. The number of fungal species was lower at the 4950-m altitude site than at the other two sites, indicating that not only altitude but also other factors affected the number of species present. All of the major species were able to decompose the cotton strips. In the CCA ordination, automatic forward selection revealed that altitude, SWC and plant root mass significantly affected fungal species composition. Our results suggest that species number and the composition of cellulolytic fungal communities are highly correlated with environmental variables as well as altitude in the alpine meadow on the Tibetan Plateau.     

Effects of different cultivation types on native and alien weed species richness and diversity in Moravia (Czech Republic)

Changes in weed species richness and beta-diversity are partly attributable to different types and intensity of disturbance and partly to broad-scale variation in environmental conditions. We compiled a data set of 434 vegetation plots of weed vegetation in root crop and cereal fields in Moravia (eastern Czech Republic) to compare the effects of environmental conditions and different disturbance regimes on species richness and beta-diversity. To detect changes in species richness, we related the variation in species richness to individual environmental conditions. To assess differences in beta-diversity between the vegetation of cereal and root crop fields, we used Whittaker's measure of beta-diversity. The relative importance of each environmental variable for the variation in species composition was evaluated using canonical correspondence analysis. All analyses were done for all vascular plant species and separately for native species, archaeophytes and neophytes. A comparison of weed vegetation of root crops and cereals showed a distinct dichotomy between these two types of weed vegetation. There was no significant difference in total species richness and native species richness; however, cereal fields were richer in archaeophytes and root crop fields were richer in neophytes. The beta-diversity of weed vegetation was higher in root crops. Environmental factors explained a significant part of the variability in richness of both natives and aliens. The richness of native species increased and beta-diversity decreased with increasing precipitation. The opposite relationship was found for archaeophytes, in both cereals and root crops. These results confirmed the importance of climatic factors and management practices for changes in weed species composition. They also showed a distinct pattern of species richness and beta-diversity of native and alien weed species.     

Relationship of butterfly diversity with nectar plant species richness in and around the Aokigahara primary woodland of Mount Fuji,central Japan

We examined the relationships between the diversities of vegetation, adult nectar plants, and butterflies in and around the Aokigahara primary woodland on the northwestern footslopes of Mount Fuji, central Japan. The results showed that the nectar resource utilization by adult butterflies was significantly biased to herbaceous plants, especially to perennials, compared to woody species, although most of the study area was in and near a primary woodland. There were greater nectar plant species in sites with greater plant species richness. Among the butterfly community indices analyzed, the strongest correlation was detected between butterfly species richness and nectar plant species richness at each site. Another close correlation was detected between the species richness of nectar plants and herbaceous plants at each site. These results suggest that herbaceous plant species richness in a habitat plays a central role in its nectar plant species richness, and the nectar plant richness is a highly important factor supporting its adult butterfly species richness. Consequently, we propose that the maintenance and management of herbaceous plant species richness in a butterfly habitat, which lead to those of its nectar plant species richness, are very important for conservation of butterfly diversity even in and around woodland landscapes of temperate regions.     

Distribution, prevalence and host associations of Hymenoptera parasitic on Calliphoridae occurring in flystrike in New Zealand

Abstract. Between 1920 and 1930, four species of parasitoid Hymenoptera (Tachinaephagus zealandicus, Alysia manducator, Nasonia vitripennis and Brachymeria ucalegon) were imported to New Zealand as an aid in the control of the blowflies causing myiasis in sheep (flystrike). Their long-term effects have never been investigated and the extent to which they were successful in establishing and enlarging their ranges has been given scant regard over the last 60 years. A long-term epidemiological study of flystrike in New Zealand between 1986 and 1996 obtained 4061 samples of blowfly larvae from flystruck sheep and carrion and overall 1.1% of these larval samples (most from the North Island) were found to be parasitized. Tachinaephagus zealandicus and A. manducator were present in field strikes, together with the endemic Aphaereta aotea recently found to be a parasite of calliphorids. The endemic species Phaenocarpa antipoda was found in association with carrion but not flystrike. Neither N.vitripennis nor B.ucalegon were isolated from larvae in field strikes, the former because it parasitizes only pupae and the latter may be extinct as it has not been sighted since its introduction in 1919.
It is concluded that if parasitoid wasps are able to locate and parasitize blowfly larvae on struck sheep, then their parasitism rate on more accessible larvae on carcases may be correspondingly greater. For this reason their scope for use in integrated management of flystrike could be increased by culturing and field release.     

Ciliate community associated with aquatic macrophyte roots: effects of nutrient enrichment on the community composition and species richness

The objective of this study was to identify the impact of nutrient enrichment on the diversity of the ciliate community associated with the roots of the aquatic macrophyte Eichhornia crassipes. The experiment was performed in the Garças Lake, located in the Upper Paraná River floodplain, Brazil. We conducted two treatments (fertilized and control) with three replicates each. To increase the initial nutrient concentrations in each mesocosm of the fertilized treatment, we added 1000 μg L⁻¹ of KNO₃ and 200 μg L⁻¹ of KH₂PO₄ during each sampling date. We found a relative high number of ciliate species (85 species) and a predominance of hypotrichs. Among the recorded species, about 25% occurred exclusively in the fertilized treatment. Moreover, detrended correspondence analysis demonstrated that the ciliate community associated with E. crassipes roots changed significantly in response to the nutrient input in such a way that the species composition of the fertilized treatment was remarkably different from that of the control. In contrast to our expectations, species richness in the fertilized treatment was significantly higher than that in the control, refuting our hypothesis that species richness decreases under eutrophic conditions.     

The effect of altitude,patch size and disturbance on species richness and density of lianas in montane forest patches

The species richness and density of lianas (woody vines) in tropical forests is determined by various abiotic and biotic factors. Factors such as altitude, forest patch size and the degree of forest disturbance are known to exert strong influences on liana species richness and density. We investigated how liana species richness and density were concurrently influenced by altitude (1700–2360 m), forest patch size, forest patch location (edge or interior) and disturbance intensity in the tropical montane evergreen forests, of the Nilgiri and Palni hills, Western Ghats, southern India. All woody lianas (≥1 cm dbh) were enumerated in plots of 30 × 30 m in small, medium and large forest patches, which were located along an altitudinal gradient ranging from 1700 to 2360 m. A total of 1980 individual lianas were recorded, belonging to 45 species, 32 genera and 21 families, from a total sampling area of 13.86 ha (across 154 plots). Liana species richness and density decreased significantly with increasing altitude and increased with increasing forest patch size. Within forest patches, the proportion of forest edge or interior habitat influenced liana distribution and succession especially when compared across the patch size categories. Liana species richness and density also varied along the altitudinal gradient when examined using eco-physiological guilds (i.e. shade tolerance, dispersal mode and climbing mechanism). The species richness and density of lianas within these ecological guilds responded negatively to increasing altitude and positively to increasing patch size and additionally displayed differing sensitivities to forest disturbance. Importantly, the degree of forest disturbance significantly altered the relationship between liana species richness and density to increasing altitude and patches size, and as such is likely the primary influence on liana response to montane forest succession. Our findings suggest that managing forest disturbance in the examined montane forests would assist in conserving local liana diversity across the examined altitudinal range.     

气候和土地利用与空间结构在影响大熊猫同域分布大中型哺乳动物物种丰富度中的相对作用

气候因子和土地利用因子是影响生物多样性分布格局的两个主要驱动因素。然而,当前关于气候因子和土地利用因子对生物多样性影响的研究主要集中在物种层面上,在群落水平上对生物多样性的影响依然知之甚少。本研究以大熊猫同域分布大中型哺乳动物为研究对象,结合物种丰富度数据、气候数据、土地利用数据以及经纬度数据,构建基于不同变量组合的多元线性模型,并通过模型拟合优度比较和方差分解等方法,探讨气候因子、土地利用因子和空间结构在影响大熊猫同域分布大中型哺乳动物物种丰富度中的相对作用。结果表明:(1)四川省大熊猫分布的五大山系内的大中型哺乳动物在属数和物种数方面差异较大。其中岷山山系的属数和物种数最高,分别为25属和28种,凉山山系的属数和物种数最低,分别为19属和20种,五大山系内排名前五的优势种分别为大熊猫、羚牛、野猪、中华斑羚、中华鬣羚;(2)大熊猫同域分布大中型哺乳动物物种丰富度在空间分布上差异较大。所有10 km×10 km栅格内的物种数在1～14之间,平均值为6.199±3.475;(3)完全模型(包含所有气候变量、土地利用变量和空间结构变量的模型,CLS)的拟合优度要好于其它6类模型,且包含土地...     

The effect of a tube-building phoronid on associated infaunal species diversity, composition and community structure

Habitat modifying organisms can alter the distribution of associated species. We surveyed soft-sediment patches in Bodega Harbor, California and found that patches with high densities of the phoronid Phoronopsis harmeri (Pixell, 1912), a chemically-defended tube-building lophophorate, have higher infaunal abundance and richness than similar patches with low densities of P. harmeri. To determine whether this difference was driven by P. harmeri and whether this difference is attributable to the activities of the organism, or simply its physical structure, we conducted a field experiment with four treatments: live phoronids, mimics of phoronid structure, phoronid-free sediments (bare) and unmanipulated sediments. Although the field experiment did not detect differences in the overall abundance or richness of infauna among the manipulated treatments, some of the individual species did show a positive response to the presence of phoronids and phoronid structure (i.e., mimics). In particular, the polychaete Boccardia proboscidea, the amphipod Monocorophium uenoi, and harpacticoid copepods were facilitated by the presence of phoronids and phoronid structure when there was sediment disturbance. The inconsistency between the results of the survey and of the manipulative experiment may be largely driven by the disturbance caused by the manipulation. However, where P. harmeri has an effect, it is generally positively associated with infaunal abundance that may be attributable to the stabilization of sediments.     

The food and feeding relationships of black oreo, Allocyttus niger, smooth oreo, Pseudocyttus maculatus, and eight other fish species from the continental slope of the south-west Chatham Rise, New Zealand

The food and feeding habits of black oreo and smooth oreo sampled at depths of 600–1200 m from the south-west Chatham Rise in 1983 are described, with notes on prey of eight other fish species. All these fish species fed benthopelagically. Black oreo preyed on hyperiid amphipods, salps and natant decapod crustaceans; smooth oreo on salps and amphipods. Dietary composition of both species changed with size of fish. Aspects of feeding relationships between the fish species were examined including dietary similarity and prey-size selection. Findings are compared with results of research on other New Zealand deepwater fish species.     

New data on lance flies (Diptera,Lonchaeidae) associated with figs (Moraceae,Ficus spp.) in Japan and Taiwan,with descriptions of two new species of the genus Silba Macquart

Larvae of the genus Silba Macquart, 1875 were obtained from the syconia of three different species of Ficus growing on the southern islands of Japan and Taiwan. Examination of the emerged adults identified four species, two of which are described as new to science: Silba erecta MacGowan and Arimoto sp. nov. and Silba thunbergii MacGowan and Arimoto sp. nov. Of the four species observed, the larvae of S. erecta, Silba ishigaki MacGowan and Okamoto, 2013 and S. thunbergii feed on the tissue of the fig syconia. Silba inubiwa MacGowan and Okamoto, 2013 was observed as a predator of three fig wasp species. The biogeographic distribution and biological data are provided for each of these fig-associated species.     

The effect of salmon redd excavation on stream substrate and benthic community of two salmon spawning streams in Canterbury,New Zealand

The effects of redd excavation by female quinnat salmon (Oncorhynchus tshawytscha walbaum) on the bentic invertebrate communities of two stable springfed spawning streams in the headwaters of the Rakaia River, South Island, New Zealand, were studied during January to September 1982. The gross effects of salmon spawning on the streams appear to be: the loss of instream macrophytes, algae and mosses, a loss of fines and detritus, and a modification of the pool-riffle character. Redd excavation may be associated with a reduction in benthic standing crop of up to 83.6%, with only a minor effect on the benthic community structure. Benthic recolonisation rates were similar for both spawning streams, with almost complete recovery after 95 days.     

The effect of butenolide on behavioral and morphological changes in two marine fouling species,the barnacle Balanus amphitrite and the bryozoan Bugula neritina

Butenolide [5-octylfuran-2(5H)-one] is a very promising antifouling compound. Here, the effects of butenolide on larval behavior and histology are compared in two major fouling organisms, viz. cypris larvae of Balanus amphitrite and swimming larvae of Bugula neritina. Butenolide diminished the positive phototactic behavior of B. amphitrite (EC₅₀ = 0.82 μg ml^?1) and B. neritina (EC₅₀ = 3 μg ml^?1). Its effect on the attachment of cyprids of B. amphitrite was influenced by temperature, and butenolide increased attachment of larvae of B. neritina to the bottom of the experimental wells. At concentrations of 4 μg ml^?1 and 10 μg ml^?1, butenolide decreased attachment of B. amphitrite and B. neritina, respectively, but the effects were reversible within a certain treatment time. Morphologically, butenolide inhibited the swelling of secretory granules and altered the rough endoplasmic reticulum (RER) in the cement gland of B. amphitrite cyprids. In B. neritina swimming larvae, butenolide reduced the number of secretory granules in the pyriform-glandular complex.     

Taxonomic and biological notes on a species of Iphitime (Polychaeta, Eunicida) associated with Pagurus prideaux from western Norway

On the basis of 658 specimens collected over an 11 year period, the symbiotic eunicid polychaete, Iphitime paguri Fage & Legendre, 1934, is redescribed, and its biology in its presumed preferred host, Pagurus prideaux Leach, 1815, is outlined. The main ecological part is based on sampling of Pagurus on five occasions throughout a year in Raunefjorden, southwest of Bergen. Iphitime paguri turned out to have a strong sexual dimorphism, both in outer appearance and in the morphology of the jaws. Both juveniles and mature individuals of both genders are described. The infestation rate of Pagurus prideaux was very high (as opposed to the low reported infestation rate in Pagurus bernhardus, generally regarded as the host of this species) and the symbiotic polychaetes turned out to have a distinct pattern of host utilization in different life stages. Ripe males and females were, at certain times of the year, generally found more or less intertwined in the apex of the gastropod shell inhabited by its host. Small larval stages were found in the same place. Intermediate size groups were found in the gill chamber and in a sulcus on the carapax of the pagurid host.     

The impact of two introduced biocontrol agents, Phytomyza vitalbae and Phoma clematidina, on Clematis vitalba in New Zealand

Insecticide and fungicide exclusion experiments were performed to determine the impact of two biological control agents, an agromyzid leaf-mining fly Phytomyza vitalbae Kaltenbach and a coelomycete fungal pathogen Phoma clematidina (Thüm.) Boerema, on the growth and percentage cover of Clematis vitalba L. (Ranunculaceae) plants. Both insecticide and fungicide treatments significantly reduced control agent damage to C. vitalba leaves over one growing season at Blenheim, New Zealand. However, damage attributable to both agents was rather low and population peaks of both agents occurred in late fall, after the main period of stem growth. There was no significant impact of treatment on growth and only a minor (8–10%), but significant, reduction in percentage cover of C. vitalba was recorded. Disease symptoms were generally only expressed late in the growing season, when leaves were senescent, and were correlated with Py. vitalbae damage. Therefore, we tentatively conclude that alone, Ph. clematidina is insufficiently pathogenic to induce disease symptoms during the main growing season of C. vitalba. Selection criteria for any future potential biocontrol pathogen, therefore, need to evaluate inherent epidemiological factors before introduction, to ensure the candidate agent is an aggressive primary pathogen that can exert maximum disease attack on the target plant. Furthermore, the potential of Py. vitalbae to exist as an asymptomatic endophyte indicates that extra care may be required when assessing survey results for non-target attack, and when testing candidate pathogen biological control agents for host specificity.     

The distribution of Austrocrangonyx new species (Crustacea: Amphipoda) on the eastern New England plateau, Australia, with reference to riparian clearing

The amphipod Austrocrangonyx n.sp. livesin forested streams above 1165m on the easternNew England plateau in NSW. Classification andRegression Tree (CART) analysis and principalcomponent biplots showed low streamtemperatures and high levels of coarseparticulate organic matter (CPOM), among manyenvironmental factors measured, were the mainfactors associated with its distribution andabundance. Riparian clearing, which increaseswater temperature and greatly reduces CPOM, isassociated with local extinction ofAustrocrangonyx. Secondary reafforestation isnot accompanied by return of the amphipod.     

Nectonema zealandica n. sp. (Nematomorpha: Nectonematoidea) parasitising the purple rock crab Hemigrapsus edwardsi (Brachyura: Decapoda) in New Zealand,with notes on the prevalence of infection and host defence reactions

A new species of Acusicola is described based on adults of both sexes taken from plankton samples collected in the upper reaches of the Piauí River estuary, in the northeast of Brazil. Ovigerous females were present in the plankton. The new species, Acusicola minuta n. sp., can be distinguished from its congeners by its small body size, female antennal morphology and leg setation. The male described here as A. minuta n. sp. is the first known male attributed to the genus.     

The role of landscape change and paleoclimatic events in shaping the evolutionary history of the Polioptila gnatcatchers (Passeriformes,Polioptilidae) with emphasis on species associated with open habitats

We conducted a large‐scale phylogenetic and biogeographical inference of the Poliptila gnatcatchers and investigated the evolutionary history of two closely related neotropical bird species linked to open habitats, Polioptila dumicola and Polioptila plumbea. A Bayesian inference was employed based on the NADH subunit 2 gene to reconstruct the phylogenetic relationship of the gnatcatchers, and ancestral area reconstructions were estimated using BioGeoBEARS. For the phylogeographic analysis, we analyzed two mitochondrial genes, cytochrome b and ND2, of 102 individuals from P. dumicola and P. plumbea distributed throughout the complete range of both species. To reconstruct the dates related to the splitting events, we included a subset of sequences from the nuclear gene beta‐fibrinogen intron‐7. A striking result was the recovery of the sister relationship between the lineages of P. dumicola /plumbea and the paraphyly among the subspecies of P. plumbea: the first group was formed by P. dumicola, P. p. plumbea, P. p. parvirostris, P. p. atricapilla and P. lactea, occurring mainly on the Brazilian shield; while the second group consisted of lineages from north of the Amazon, west of the Andes, and Central America, and included P. maior, P. p. cinericia, P. p. bilineata and P. p. innotata. Significant phylogeographic structure was evident within lineages attributed to P. plumbea, with high levels of differentiation in the well‐defined clades according to all phylogenetic analyses. Our biogeographic analyses support distinct evolutionary histories related to founder events and vicariance, occurring during the late Pliocene and early Pleistocene. Several dispersal episodes between North/Central America and South America led to the establishment of populations which became differentiated due to landscape changes, such as the establishment of riverine barriers, the uplift of the Andes and the formation of the Panama Isthmus.