Seasonal distribution of abundance, biomass and secondary production of free-living nematodes and their community composition in different stream micro-habitats

Nematology ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 401-422 ◽  
Author(s):  
Henrike Brüchner-Hüttemann ◽  
Walter Traunspurger

Summary The nematode communities of four different micro-habitats in an unpolluted first-order stream were investigated over a 13-month period in a study of the sediment and the biofilms on dead wood, macrophytes and leaf litter. Nematode abundances, biomass and secondary production were analysed, together with the species composition, proportion of feeding types and diversity of the nematode communities of the micro-habitats. Differences between the investigated micro-habitats in terms of seasonal variations, species composition, proportion of feeding types and diversity were expected. The annual mean values of nematode abundance, biomass and secondary production differed significantly between the micro-habitats. Abundances were highest on dead wood, whereas biomass and secondary production were highest in sediment. In the sediment and on leaf litter, nematode abundance and biomass showed pronounced seasonal patterns. The largest contribution to the total secondary production of the stream was from sediment nematodes. In total, 108 nematode species were detected in the micro-habitats during the 13-month study. Comparisons between them revealed differences in nematode species composition. The annual mean species number was significantly higher in sediment and on leaf litter than on dead wood and macrophytes, whereas the annual mean Shannon-Wiener index was significantly higher in sediment than at all other micro-habitats. All micro-habitats in the studied stream, as well as the stream as a whole, were dominated by nematode species belonging to the deposit feeders. Our study clearly showed that the composition of nematode communities from different micro-habitats within a single stream reach can differ markedly.

2020 ◽  
Vol 54 (4) ◽  
pp. 1079-1095
Author(s):  
Henrike Brüchner-Hüttemann ◽  
Christoph Ptatscheck ◽  
Walter Traunspurger

Abstract Meiofaunal abundance, biomass and secondary production were investigated over 13 months in an unpolluted first-order stream. Four microhabitats were considered: sediment and the biofilms on dead wood, macrophytes and leaf litter. The relative contribution of the microhabitats to secondary production and the influence of environmental factors on meiofaunal density distribution were estimated. We expected (1) meiofaunal abundance and biomass to exhibit seasonal patterns, with more pronounced seasonal fluctuations on macrophytes and leaf litter than in the other microhabitats, (2) annual secondary production to be highest in sediment; however, the relative contribution of the microhabitats to monthly secondary production would change during the year, and (3) a bottom-up driven influence on meiofaunal density distribution in the microhabitats. Meiofaunal annual mean abundance, biomass and secondary production were 7–14 times higher in sediment and on dead wood than on macrophytes and leaf litter. Significant seasonal patterns described the meiofaunal abundance in sediment and on leaf litter as well as the biomass in sediment, on macrophytes and leaf litter. Organisms in sediment and on dead wood contributed 48 and 43%, respectively, to secondary production m−2, but in regard to the stream area covered by the microhabitats, sediment had the highest share (80%). Significant determinants of the density distribution were AFDM, protozoans, bacteria and Chl-a, which influenced all meiofaunal groups. Our study clearly indicates that meiofaunal organisms in sediment and on dead wood have a remarkable share on total secondary production of lotic systems which is especially relevant for forested low-order streams.


Nematology ◽  
2005 ◽  
Vol 7 (2) ◽  
pp. 267-280 ◽  
Author(s):  
Lars Peters ◽  
Walter Traunspurger

AbstractRecent studies on meiofaunal and nematode communities have focused on soft sediments in streams, lakes and marine environments. Despite a large number of studies dealing with periphyton, meiofaunal and nematode communities, on littoral hard substrates in lakes have not yet been investigated in detail. Therefore, epilithic communities with particular emphasis on nematode species composition, were analysed in 17 Swedish lakes differing greatly in size, depth, trophic status and epilithic biomass. Nematode abundance ranged from 2.3 to 161.5 cm−2, and the abundance of nematodes relative to total meiofauna ranged from 20 to 77% (mean 53%). Fifty-eight nematode species were identified; species numbers varied from eight to 34 species per lake. The dominant species were Rhabdolaimus aquaticus, Punctodora ratzeburgensis, Eumonhystera dispar and Crocodorylaimus flavomaculatus. Deposit feeders dominated (71% of total fauna), followed by suction feeders (14%), epistrate feeders (12%) and chewers (3%). Of 3624 nematodes examined, 54% were juveniles, 35% females, 6% males and 5% gravid females. Multivariate analysis of the nematode species composition revealed significant differences in the community structures among lakes. This is the first study to show that meiofauna is a numerically abundant group within littoral periphyton communities in lakes, with nematodes representing the dominant group.


Author(s):  
T. M. Zhylina ◽  
V. L. Shevchenko

The taxonomic structure of the nematodes and the thickness in the forest litter of the Mezin National Nature Park were studied. Samples were collected during 2008-2010 and 2014 (June – July) in 21 forest ecosystems. Nematodes were extracted by a modified Baermann's method from the sample of 5 g. The exposition time was 48 h. Extracted nematodes were fixed in the triethanolamine–formalin (TAF, 2 % triethanolamine, 7 % formaldehyde solution, 91 % water), and mounted on the temporary hydroglyceric slides. To describe the taxonomic structure of nematode communities we calculated the proportion of each order (family) in the community as the ratio (in %) of the individuals of each order (family) to the total number of nematodes. 46 nematode species belonging to 36 genera, 21 families and 10 orders were identified. The average number of nematodes was 4256 per 100 g of substrate. The number of nematodes varied from 220 to 11920 specimens per 100 g in separate samples. Most of the identified species (78.26 %) belong to the four orders: Tylenchida (10 species), Plectida (9 species), Rhabditida (9 species), Dorylaimida (8 species) or 21.74 %, 19.57 %, 19.57 % and 17.39 % of the species composition, respectively. The orders of Enoplida, Triplonchida, Araeolaimida, Mononchida, Monhysterida and Teratocephalida are represented by 1 to 2 species (4.35 – 2.17 % of the total number of identified species). In terms of quantitative representation, species of Plectida are dominant (proportion in the community 43.15 %). This proportion was 2.5 times higher than the number of representatives of Tylenchida (17.07 %), Dorylaimida (17.01 %) and Rhabditida (16.44 %). Comparatively, the largest number of species found belong to the families Plectidae (9 species), Cephalobidae (6 species), and Tylenchidae (5 species). Only six nematode families were represented in the forest litter samples, namely: Plectidae (with proportion in the community 43.15 %), Dorylaimidae (with proportion in the community 13.74 %), Aphelenchoididae (with 8.99 %), Panagrolaimidae (with 8.17 %), Tylenchidae (with 5.90 %), Mesorhabditidae (with 5.48 %).


Nematology ◽  
2005 ◽  
Vol 7 (6) ◽  
pp. 901-916 ◽  
Author(s):  
Walter Traunspurger ◽  
Karl-Otto Rothhaupt ◽  
Lars Peters ◽  
Markus Wetzel

AbstractThe development of an epilithic nematode community and the mode of colonisation was monitored over a 57-day period during spring in a field experiment in the littoral zone of a large oligotrophic lake. Two types of experimental units were used: one type prohibited direct colonisation via active crawling by elevating substrates into the water column and the second type had substrates placed on the lake bottom. Data from the two types of units and from nearby natural hard substrates were compared. The nematodes quickly colonised on the introduced substrates and reached maximum densities of 123 individuals per 10 cm2 after 57 days. Nematode densities on elevated and non-elevated substrates did not differ significantly. The nematode abundance and community structure showed a large initial variation, but became more stable over time and resembled the natural community structure at the end of the experiment. The maximum number of nematode species was reached after 2 weeks of colonisation, with a maximum species number on days 12 and 14 in the experimental units and on day 19 on the surrounding natural hard substrates. The five numerically dominant species, Eumonhystera vulgaris, Chromadorina bioculata, Eumonhystera filiformis, Chromadorina viridis and Daptonema dubium, accounted for most of the variation between the different communities. The results indicate that water-column transport was the main colonisation pathway of epilithic nematodes. The distribution of nematode species points to potential morphological adaptations of some species for persistence on hard substrates.


Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2103
Author(s):  
Marek Renčo ◽  
Jana Jurová ◽  
Erika Gömöryová ◽  
Andrea Čerevková

Heracleum mantegazzianum (giant hogweed) is the largest central European forb, naturalized or invasive in many European countries. The impacts of its colonization of native habitats on soil mesofauna groups are unfortunately obscure. This study assessed the effect of giant hogweed invasion on the communities of plants and soil nematodes in the riparian habitat. We found that invasion by H. mantegazzianum increased soil pH, decreased carbon and nitrogen content, reduced the number and coverage of the native plant species, and influenced nematode communities and their structures. Nematode species number was significantly lower in invaded than uninvaded plots, but nematode species diversity was not affected by invasion throughout the whole study. Total nematode abundance slightly increased under giant hogweed, while total nematode biomass did not differ between the invaded and uninvaded plots. The higher abundance of bacterivores and fungivores but lower number of omnivorous nematodes well represented the negative impact of giant hogweed invasion on soil food webs, supported by low values of all maturity indices or channel index. The hogweed invaded plots contained higher abundance of plant parasitic nematodes, mainly Paratylenchus microdorus. Our results thus indicate that invasion by H. mantegazzianum influences several nematode communities’ parameters while others remain unaffected by invasion.


2012 ◽  
Vol 87 (3) ◽  
pp. 376-385 ◽  
Author(s):  
A. Čerevková ◽  
M. Renčo ◽  
L. Cagáň

AbstractThe nematode communities in spruce forests were compared with the short-term effects of forest damage, caused by windstorm, wildfire and management practices of forest soils. Soil samples were collected in June and October from 2006 to 2008 in four different sites: (1) forest unaffected by the wind (REF); (2) storm-felled forest with salvaged timber (EXT); (3) modified forest affected by timber salvage (wood removal) and forest fire (FIR); and (4) storm-felled forest where timber had been left unsalvaged (NEX). Nematode analysis showed that the dominant species in all four investigated sites were Acrobeloides nanus and Eudorylaimus silvaticus. An increase of A. nanus (35% of the total nematode abundance) in the first year in the FIR site led to the highest total abundance of nematodes compared with other sites, where nematode abundance reached the same level in the third year. In the FIR site bacterial feeders appeared to be the most representative trophic group, although in the second and third year, after disturbance, the abundance of this trophic group gradually decreased. In the NEX site, the number of nematode species, population densities and Maturity Index were similar to that recorded for the FIR site. In EXT and NEX sites, the other dominant species was the plant parasitic nematode Paratylenchus microdorus. Analyses of nematodes extracted from different forest soil samples showed that the highest number of species and diversity index for species (H'spp) were in the REF site. Differences between the nematode fauna in REF and other localities were clearly depicted by cluster analysis. The greatest Structure Index and Enrichment Index values were also in REF. In the EXT site, the number of nematode species, their abundance, H'spp and Maturity Index were not significantly different from those recorded in the reference site.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shahid Afzal ◽  
Humira Nesar ◽  
Zarrin Imran ◽  
Wasim Ahmad

AbstractDespite enormous diversity, abundance and their role in ecosystem processes, little is known about how community structures of soil-inhabiting nematodes differ across elevation gradient. For this, soil nematode communities were investigated along an elevation gradient of 1000–2500 masl across a temperate vegetation in Banihal-Pass of Pir-Panjal mountain range. We aimed to determine how the elevation gradient affect the nematode community structure, diversity and contribution to belowground carbon assimilation in the form of metabolic footprint. Our results showed that total nematode abundance and the abundance of different trophic groups (fungivores, herbivores and omnivores) declined with the increase of elevation. Shannon index, generic richness and evenness index indicated that nematode communities were more diverse at lower elevations and declined significantly with increase in elevation. Nematode community showed a pattern of decline in overall metabolic footprint with the increase of elevation. Nematode abundance and diversity proved to be more sensitive to elevation induced changes as more abundant and diverse nematode assemblage are supported at lower elevations. Overall it appears nematode abundance, diversity and contribution to belowground carbon cycling is stronger at lower elevations and gradually keep declining towards higher elevations under temperate vegetation cover in Banihal-pass of Pir-Panjal mountain range.


2018 ◽  
Vol 23 (1) ◽  
pp. 1 ◽  
Author(s):  
Colin K. C. Wen ◽  
Li-Shu Chen ◽  
Kwang-Tsao Shao

Spatial and temporal variations in the species composition of assemblages are common in many marine organisms, including fishes. Variations in the fish species composition of subtidal coral reefs have been well documented, however much less is known about such differences for intertidal fish assemblages. This is surprising, given that intertidal fishes are more vulnerable to terrestrial human disturbances. It is critical to evaluate the ecology and biology of intertidal fishes before they are severely impacted by coastal development, especially in developing countries such as those in the tropical western Pacific region where coastal development is rapidly increasing. In this study, we investigated the species composition, abundance, biomass and species number (richness) for intertidal fish assemblages in subtropical (northern) and tropical (southern) Taiwan across four seasons by collecting fishes from tidepools using clove oil. We also examined the gut contents of collected fishes to identify their trophic functional groups in order to investigate regional and seasonal variations for different trophic groups. We found significant differences in the species composition of tidepool fish assemblages between subtropical and tropical Taiwan. Bathygobius fuscus, Abudefduf vaigiensis and Istiblennius dussumieri were dominant species in subtropical Taiwan, whereas Bathygobius coalitus, Abudefduf septemfasciatus and Istiblennius lineatus were dominant in tropical Taiwan. Other species such as Bathygobius cocosensis, Abudefduf sordidus and Istiblennius edentulus were common in both regions. For trophic groups, omnivores and detritivores had or showed trends towards higher species numbers and abundances in the subtropical region, whereas herbivores, planktivores and general carnivores had or showed trends towards higher species numbers and biomass in the tropical region. Overall, many intertidal fish species and trophic groups showed differences in abundance, biomass and species number between subtropical and tropical Taiwan. Further studies on large scale geographical gradients in trophic groups and species compositions in the Indo-west Pacific region are encouraged to assist with ecosystem monitoring and assessment. Keywords: Intertidal fishes, spatio-temporal pattern, feeding guild, diet


2007 ◽  
Vol 250 (1-2) ◽  
pp. 77-88 ◽  
Author(s):  
I. Vanha-Majamaa ◽  
S. Lilja ◽  
R. Ryömä ◽  
J.S. Kotiaho ◽  
S. Laaka-Lindberg ◽  
...  

Author(s):  
V. L. Shevchenko ◽  
T. M. Zhylina

The species composition, frequency of occurrence, and the abundance of phytohelminths in communities of soil nematodes in natural ecosystems of the Left-Bank Polissia (Chernihiv region) were studied. Samples were collected throughout 2011-2016 in forest and meadow ecosystems on the territory of Chernihivskyi, Horodnianskyi, Kozeletskyi, Koropskyi, Menskyi, Ripkynskyi, Sosnytskyi, Semenivskyi, Shchorskyi and Novhorod-Siverskyi districts. Nematodes were extracted by a modified Baermann’s method from the 20-g sample. The exposition time was 48 h. Extracted nematodes were fixed in the triethanolamine–formalin (TAF, 2 % triethanolamine, 7 % formaldehyde solution, 91% water), and mounted on the temporary hydroglyceric slides. Nematode abundance was expressed as specimens per 100 g of dry soil. Seventeen species from three orders, ten families and fifteen genera were found. Eleven species (64.7 % of the species composition) belonged to the order of Tylenchida, four (23.5 %) – Triplonchida, two (11.8 %) – Dorylaimida. Eleven species (Gracilacus audriellus, Paratylenchus nanus, Tylenchorhynchus dubius, Helicotylenchus dihystera, Macroposthonia annulata, Diphtherophora communis, Trichodorus primitivus, Paratrichodorus teres, Paratrichodorus pachydermus, Longidorus elongatus, Xiphinema index) are ectoparasites, three species (Ditylenchus dipsaci, Pratylenchus pratensis, Hirschmaniella gracilis) – endoparasites, and three species (Hemicycliophora sp., Heterodera sp. 1, Heterodera sp. 2) – semiendoparasites. Phytohelminths in communities of soil nematodes in forest ecosystems ranged from 9.4 to 26.3 %. But in meadow ecosystems of the Mezin National Nature Park it was a dominant group (proportion in the community 47%). The most frequent species were G. audriellus, H. dihystera and T. dubius which occurred in 33.3 %, 33.3 % and 28.3 % of samples respectively. P. nanus, D. dipsaci, P. pratensis та D. communis – had frequency of occurrence 15 – 20%. Ten species of phytohelminths were found in 1–4 ecosystems (1.7–6.7%). G. audriellus and H. dihystera were abundant (124 and 56 specimens per 100 g of soil respectively).


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