Experimental removal of a dominant species at two levels of soil fertility

1989 ◽  
Vol 67 (12) ◽  
pp. 3470-3477 ◽  
Author(s):  
Jessica Gurevitch ◽  
Robert S. Unnasch
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Soil Fertility ◽  
Dominant Species ◽  
Dactylis Glomerata ◽  
Common Species ◽  
Herbaceous Plant ◽  
Old Field ◽  
Steep Decline ◽  
Dactylis Glomerata L

Fertilization of the soil in herbaceous plant communities has been observed to lead to an increase in productivity but a decline in species richness and diversity. We tested the hypothesis that the decline in diversity is due to increased competition from a dominant species by removing the dominant species, Dactylis glomerata L., from an old field community with and without fertilization. Fertilization without the removal of Dactylis resulted in a steep decline in species numbers and in species diversity. The removal of Dactylis when fertilizer was added prevented the decline in species richness. Removal of this dominant species led to an increase in species diversity, an increase in either the frequency or the abundance of almost half of the common species in the system, and an increase in the combined biomass of uncommon species. The response to the removal of Dactylis was greater at higher than at low soil fertility for most but not all variables. Key words: old-field, fertilization, competition, species diversity, community structure, Dactylis glomerata.

scholarly journals Composition and diversity of anurans in the Restinga of the Conde municipality, northern coast of the state of Bahia, northeastern Brazil

2016 ◽  
Vol 16 (3) ◽  
Author(s):  
Felipe Augusto Trindade Gondim-Silva ◽  
Alessandra Rodrigues Santos Andrade ◽  
Rafael Oliveira Abreu ◽  
Jamile Santos Nascimento ◽  
Geovane Paixão Corrêa ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Species Composition ◽  
Rainy Season ◽  
Dominant Species ◽  
The State ◽  
Northeastern Brazil ◽  
Freshwater Wetland ◽  
Northern Coast ◽  
Anuran Species

Abstract The Conde municipality is located in the northern coast of the state of Bahia (NC), northeastern Brazil, and is part of the Atlantic Tropical domain. The anuran fauna of the northern portion of the NC is still poorly known if compared to the southern portion. The Restinga is one of the predominant environments of the coastal plains of the NC and it is characterized essentially by presenting sandy soil covered by herbaceous and shrubby vegetation. The objective of this study was to determine the anuran species composition and diversity for the Restinga of the Conde municipality. Sampling was carried out at night by active search over four periods of five consecutive days each, two over the 'main rainy season' and two in a 'lesser rainy season', using 14 sample units (SUs) and five extra sample plots (EPs). We calculated dominance and species diversity using the Berger-Parker and Shannon-Wiener H' indices, respectively. We used accumulation curves and the Jackknife 1 estimator to estimate anuran species richness, considering only the data obtained from the SUs. We recorded 713 anuran specimens distributed within 33 species, 13 genera and five families (Bufonidae, Craugastoridae, Hylidae, Leptodactylidae and Microhylidae). The Hylidae and Leptodactylidae families had the highest species richness. Considering only the SUs (Jackknife 1 estimator in brackets), we recorded 28 species in the study area (33.9 ± 2.3), 13 in Shrubby Vegetation Zones - SVZ (20.8 ± 2.9) and 25 in Freshwater Wetland Zones - FWZ (28.9 ± 1.9). The abundance and species diversity of the FWZ (n = 638 specimens; H'= 2.4) were higher than those recorded for the SVZ (n = 52 specimens; H' = 1.9). The SVZ and FWZ showed distinct dominant species, wherein Pristimantis paulodutrai was the dominant species in SVZ and Scinax fuscomarginatus in FWZ. The Restinga of the Conde municipality stands out as the one with the highest anuran species richness already recorded considering only SVZ and FWZ. Moreover, its anuran species composition represented 55% of the anuran species known for the NC and included taxa common to three different morphoclimatic domains (Tropical Atlantic, Cerrado and Caatinga).

scholarly journals Plant community diversity and composition provide little resistance to Juniperus encroachment

Botany ◽  
2008 ◽  
Vol 86 (12) ◽  
pp. 1416-1426 ◽  
Author(s):  
Amy C. Ganguli ◽  
David M. Engle ◽  
Paul M. Mayer ◽  
Eric C. Hellgren
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Species Composition ◽  
Plant Species ◽  
Plant Community ◽  
Tallgrass Prairie ◽  
Abiotic Factors ◽  
Community Diversity ◽  
Oak Forest ◽  
Old Field

Widespread encroachment of the fire-intolerant species Juniperus virginiana  L. into North American grasslands and savannahs where fire has largely been removed has prompted the need to identify mechanisms driving J. virginiana encroachment. We tested whether encroachment success of J. virginiana is related to plant species diversity and composition across three plant communities. We predicted J. virginiana encroachment success would (i) decrease with increasing diversity, and (ii) J. virginiana encroachment success would be unrelated to species composition. We simulated encroachment by planting J. virginiana seedlings in tallgrass prairie, old-field grassland, and upland oak forest. We used J. virginiana survival and growth as an index of encroachment success and evaluated success as a function of plant community traits (i.e., species richness, species diversity, and species composition). Our results indicated that J. virginiana encroachment success increased with increasing plant richness and diversity. Moreover, growth and survival of J. virginiana seedlings was associated with plant species composition only in the old-field grassland and upland oak forest. These results suggest that greater plant species richness and diversity provide little resistance to J. virginiana encroachment, and the results suggest resource availability and other biotic or abiotic factors are determinants of J. virginiana encroachment success.

scholarly journals Orchid bee fauna responds to habitat complexity on a savanna area (Cerrado) in Brazil.

Sociobiology ◽  
2016 ◽  
Vol 63 (2) ◽  
pp. 819 ◽  
Author(s):  
Yasmine Antonini ◽  
Rodrigo Assunção Silveira ◽  
Márcio Oliveira ◽  
Cristiane Martins ◽  
Reisla Oliveira
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Habitat Complexity ◽  
Habitat Structure ◽  
Dominant Species ◽  
Large Range ◽  
Physical Structure ◽  
High Complexity ◽  
Orchid Bee ◽  
Species Richness And Abundance

Habitat structure and complexity may broadly affect the diversity and composition of a variety of fauna in terrestrial systems. Here we investigated responses of orchid bee assemblages to habitat complexity, with the aim of assessing complexity as a useful surrogate for species diversity of this group. We test the following hypotheses: (i) There is a greater species richness and abundance of orchid bee in sites with high habitat complexity than lower habitat complexity; (ii) High habitat complexity sites have a different species composition of orchid bee than lower habitat complexity sites. For the purposes of our study, we defined habitat complexity as the heterogeneity in the arrangement in physical structure of habitat (vegetation), although there are a large range of operational definitions in the literature. As result, orchid bee species richness was higher in high complexity areas while community composition was not affected by habitat complexity, because Euglossa melanotricha and E. leucotricha were the dominant species, occurring in both environments. Habitat complexity, measured as a function of differences in multiple strata in forests, may be of great worth as a surrogate for the diversity of a range of arthropod groups including orchid bees. 

scholarly journals DEDEYOLU GÖLETİ (ELAZIĞ–TÜRKİYE) ZOOPLANKTONU

2020 ◽  
Vol 15 (4) ◽  
pp. 143-154
Author(s):  
Serap Saler
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Dominant Species ◽  
Positive Relationship ◽  
Ph Value ◽  
Strong Positive Correlation ◽  
Keratella Cochlearis ◽  
Index Value ◽  
Richness Index ◽  
Number Of Individuals

In this study, it is aimed to determine the zooplankton and species diversity of Dedeyolu Pond. Zooplankton samples were taken from 3 stations in monthly periods between May 2011 and April 2012. In the research, 17 species belonging to Rotifera, 6 species belonging to Cladocera and 2 species belonging to Copepoda were identified in Dedeyolu Pond. Among all zooplankton, it was represented Rotifera with 81%, Cladocera with 14% and Copepoda with 5%. Species diversity reached its highest value in April (H'=2.34) in the 3rd station, and the Margalef species richness index value reached its highest value in the first station (D=3.84) in October. There were a strong positive correlation between the number of individuals and the temperature in Dedeyolu Pond (r=0.674), a weak positive relationship between the number of individuals and the pH value (r=0.370), and a weak positive relationship between the number of individuals and the dissolved oxygen value (r=0.290). Keratella cochlearis species was recorded as the dominant species in all seasons in the pond.

Spatial-typological structure of blackflies communities (Diptera: Simuliidae) of the River Tisa basin within of the Ukrainian Carpathians

2019 ◽  
Vol 15 (2) ◽  
pp. 59-70
Author(s):  
A. M. Tepliuk ◽  
K. B. Sukhomlin
Keyword(s):  
Species Diversity ◽  
High Altitude ◽  
River Basin ◽  
Dominant Species ◽  
Common Species ◽  
High Mountain ◽  
Typological Structure ◽  
Subdominant Species

A total of 46 species of blackflies from 2 genera were recorded in the watercourses of the Tisa River basin within Ukrainian Carpathians. In qualitative terms, the genus Simulium Latreille, 1802 predominates, with 42 species in 5 subgenera: Nevermannia Enderlein, 1921 (9 species), Eusimulium Roubaud, 1906 (2 species), Wilhelmia Enderlein, 1921 (4 species), Obuchovia Rubtsov, 1947 (2 species) and Simulium Latreille, 1802 (25 species). The genus Prosimulium Roubaud, 1906 is represented with only 4 species. Moreover, 33 species develop in streams (the index of the species diversity of Simpson (Is) is 0,094), and 32 species (Is – 0,087) of Simuliidae develop in rivers. There are 19 common species for both types of watercourses (the index of similarity of Chekanovsky-Sorensen (I) is 0.37). Only 14 species of blackflies develop in streams, and only 13 species develop in rivers. Two dominant species (S. (s.str.) intermedium, S. (s.str.) trifasciatum) and 4 subdominant species (S. (s.str.) argyreatum, S. (s.str.) ornatum, S. (s.str.) reptans, S. (s.str.) variegatum) form the nucleus of the fauna Simuliidae of the Tisa River basin. The species diversity of blackflies reaches 33 species (Is – 0,075) at watercourses of the low mountain level (at altitudes up to 499 m), is has 38 species (Is – 0,067) at the middle mountain level (500–999 m) and only 24 species (Is – 0,021) at high mountain level (above 1000 m). Only 6 species (S. (Eusimulium) velutinum, S.(Obuchovia) brevifile, S. (s.str.) noelleri, S. (s.str.) rostratum, S. (s.str.) tuberosum and S. (s.str.) voilense) develop in the watercourses of the low mountain level, 5 blackfly species (S. (Nevermannia) codreanui, S. (Wilhelmia) pseudoequinum, S. (s.str.) argenteostriatum, S. (s.str.) paramorsitans and S. (s.str.) vulgare) develop in the watercourses of the middle mountain level and 2 species blackflies (S. (Nevermannia) crenobium and S. (Nevermannia) oligotuberculatum) develop in the watercourses of the high mountain level. There are 16 species of Simuliidae common for this high altitude belts, among them S. (Nevermannia) vernum, S. (s.str.) fontanum, S.(s.str.) intermedium, S.(s.str.) ornatum and S. (s.str.) trifasciatum did not reveal the definite patterns of belonging to the specific altitudes, since their quantity was approximately the same at different heights.

scholarly journals Herbaceous species diversity patterns across various treatments of herbivory and fire along the sodic zone of the Nkuhlu exclosures, Kruger National Park

Koedoe ◽  
2013 ◽  
Vol 55 (1) ◽  
Author(s):  
Helga Van Coller ◽  
Frances Siebert ◽  
Stefan J. Siebert
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Plant Species ◽  
Significant Variation ◽  
National Park ◽  
Plant Species Richness ◽  
Kruger National Park ◽  
Riparian Zones ◽  
Herbaceous Plant ◽  
Herbaceous Species

Understanding relationships between large herbivores and plant species diversity in dynamic riparian zones is critical to biodiversity conservation. The Nkuhlu exclosures in the Kruger National Park (KNP) provided opportunity to investigate spatial heterogeneity patterns within riparian zones, as well as how these patterns are affected by fire and herbivory. A monitoring project was initiated to answer questions about the dynamics of the herbaceous layer and was aimed at determining, (1) whether there exists meaningful variance in herbaceous plant species richness and diversity across different treatments in the ecologically sensitive sodic zone and (2) whether an increase in herbaceous biomass, an artefact of herbivory and fire exclusion, suppresses herbaceous plant species diversity and richness. Herbaceous vegetation was sampled in two 1 m2 circular sub-plots in the eastern and western corners of 81 fixed plots. The biomass of each plot was estimated with a disc pasture meter (DPM) diagonally with the plot. DPM-readings were converted to kg/ha, according to the latest conversions for the Lowveld Savanna. Species richness and biomass showed significant variance across treatments, whereas no significant variation in herbaceous species diversity was perceived. Combined treatment of fire absence and herbivore presence contributed to higher forb species richness in the sodic zone. Biomass is significantly higher in fully fenced areas where herbivores are excluded, as opposed to the open and partially fenced areas. Although no significant variation was recorded for diversity across treatments, lowest diversity was recorded in the absence of all herbivores, especially in combination with fire treatment. Therefore herbivores are essential in sustaining herbaceous plant species richness in the sodic zone, whilst no significant results were found with regard to their effect on species diversity. Although statistically non-significant, fire seems to suppress species richness.Conservation implications: This study could be used as framework to advance and develop science-based management strategies for, at least, the sodic zones of the KNP. Research in these exclosures will create better understanding of these landscapes, benefit ecosystem conservation planning of national parks and also provide valuable long-term information on key ecological processes.

scholarly journals Особливості структури комплексів фітосеїдних кліщів в рослинних асоціаціях міст

2017 ◽  
Vol 7 (4) ◽  
pp. 179-186
Author(s):  
S L. Grabovska ◽  
I. I. Mykolaiko ◽  
V. P. Mykolaiko
Keyword(s):  
Species Diversity ◽  
Dominant Species ◽  
Common Species ◽  
Mite Species ◽  
Herbaceous Plants ◽  
Species Structure ◽  
Predacious Mites ◽  
Phytoseiid Mites ◽  
Trees And Shrubs ◽  
Subdominant Species

20 species of 10 genera of mites of this family Phytoseiidae were found while studying a species composition on the plants of urban environment Amblyseius andersoni Chant, 1957; Amblyseius rademacheri Dosse, 1958; Neosiulus herbarius Wainstein, 1960; Neoseiulus reductus Wainstein, 1962; Euseius finlandicus, Oudemans, 1915; Kampimodromys aberrans Ouderman, 1930; Dubininellus echinus Wainstein et Arutunjan, 1970; Dubininellus juvenis Wainstein et Arutunjan, 1970; Typhlodromus cotoneastri Wainstein, 1961; Typhlodromus laurae Arutunjan, 1974; Typhloctonus aceri Collyer, 1957; Typhloctonus tiliarum Oudemans, 1930; Paraseiulus incognitus Wainstein et Arutunjan, 1967; Paraseiulus soleiger Ribaga, 1902; Amblydromella (s.str.) caudiglans Scheuten,1959; Amblydromella (s.str.) pirianykae Wainstein, 1972; Amblydromella (s.str.) rhenana Oudemans, 1905; Amblydromella clavata Wainstein, 1972; Amblydromella (Aphanoseius) verrucosa Wainstein, 1972; Galendromus longipilus Nesbitt, 1951. The peculiarities of their spreading in plant associations of Kyiv city, Uman city, Vasylkiv town, Brovary town (Ukraine) which differed from each other by various characteristics (population, area, urbanization degree, etc.) were determined. Total 68 species of plants were examined in the territory of Kyiv city where there were 40 species of trees and shrubs (including 2 types of conifers) and 28 species of herbaceous plants; 16 species of 10 genera of predacious phytoseiid mites were found. 14 species of 8 genera of mites were registered on 25 plant species in the territory of Brovary town (16 species of tree-and-shrub and 9 species of herbaceous plants) in the result of processing of collected materials. 10 species of 7 genera were identified while studying the current state of species diversity of predacious mites of Phytoseiidae family on 26 species of trees and shrubs of green urban plantations within Vasylkiv town. 12 species of 7 genera of Phytoseiidae mites were identified in the result of study of urban plantations in Uman city. Common species at studied areas were the following seven species: A. andersoni, A. rademacheri, E. finlandicus, K. aberrans, T. laurae, T. aceri, T. tiliarum. During the researches the domination index (Di). It was found that spreading of mites was different. Dominant species, subdominant species, subdominant of first order and minor members of species complexes were revealed while analysed the species structure of predacious phytoseiidae mites. E. finlandicus was the dominant in all research plots: Kyiv (Di = 51.63 %), Uman (Di = 60.32 %), Vasylkiv (Di = 15.65 %), Brovary (Di = 33.90 %). K. aberrans (Di = 15.52 %) and E. finlandicus was determined as dominant species n Vasylkiv town. K. aberrans (Di = 2.35 %) and T. aceri (Di = 1.30 %) had the status of subdominant species in research areas. We also have been studied the mite species diversity on the grass and shrubs. We studied the mites on the 93 species of plants where 55 were trees and shrubs (58.9 %) and 38 species were the herbaceous plants (41.1 %).

Monogenean community structure on the gills of Pimelodus albicans from Río de la Plata (Argentina): a comparative approach

Parasitology ◽  
2001 ◽  
Vol 122 (4) ◽  
pp. 465-470 ◽  
Author(s):  
P. A. GUTIÉRREZ
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Dominant Species ◽  
Species Abundance ◽  
Common Species ◽  
Comparative Approach ◽  
Rio De La Plata ◽  
Component Community ◽  
Río De La Plata ◽  
La Plata

The community structure of monogeneans on the gills of a catfish Pimelodus albicans, in the Río de la Plata, was studied and compared with previous findings on P. maculatus. Six Monogenea species belonging to 3 genera were found: Demidospermus majusculus Kritsky & Gutiérrez, 1998; Demidospermus armostus Kritsky & Gutiérrez, 1998; Demidospermus idolus Kritsky & Gutiérrez, 1998; Demidospermus bidiverticulatum (Suriano & Incorvaia, 1995) Kritsky & Gutiérrez, 1998; Scleroductus yuncensi Jara & Cone, 1989; and Unibarra paranoplatensis Suriano & Incorvaia, 1995. The relationships between selected host and helminth variables; the interactions between the worms and the patterns obtained from the species abundance were analysed employing appropriate statistical methodology. The results obtained revealed the following common patterns within the monogenean communities of P. maculatus and P. albicans: (a) most monogenean species belonged to the genus Demidospermus; (b) S. yuncensi was a secondary species in both communities; (c) 1 of the 3 species common to both hosts was a core species (D. bidiverticulatum); (d) the selected variables of both hosts (weight and length) were not related to the number of monogeneans or species richness; (e) the dominant species in both communities showed the highest proportion of monogeneans in more than 40 % of the infracommunities; (f ) in both communities the dominant species accounted for 40–80 % of the total number of monogeneans at component community level; (g) the number of worms correlates positively with the species richness; (h) few cases of interaction among species were found; (i) a high degree of order exists among the infracommunities compared. Finally, the proportion of common species and the phylogenetic and ecological resemblances between the hosts, P. maculatus and P. albicans support a hypothesis of co-speciation among monogeneans and pimelodids in Río de la Plata. It seems improbable that these parasite communities are recent species assemblages formed by chance. The phylogenetic resemblance of the host–monogeneans system in Río de la Plata suggests that there is a single community pattern that can be observed in congeneric and sympatric hosts.

Flooding, topography, and successional age as determinants of species diversity in old-field vegetation

1996 ◽  
Vol 74 (4) ◽  
pp. 582-588 ◽  
Author(s):  
Hernán J. Trebino ◽  
Enrique J. Chaneton ◽  
Rolando J. C. León
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Early Stage ◽  
Biotic Interactions ◽  
First Year ◽  
Spatial And Temporal Patterns ◽  
Old Field ◽  
Flood Disturbance ◽  
Topographic Positions ◽  
Topographic Gradients

We studied the spatial pattern of plant richness and diversity along topographic gradients in two pairs of plots with 3 and 4 versus 9 and 10 years of abandonment from cultivation, in the Inland Pampa of Argentina. Vegetation in each plot was sampled for species cover every 10 m along a transect running parallel to the maximum local slope. Observations began after 2 years of unusually severe floods and continued for over 6 years. Community richness and diversity both increased with topographic height only the first year after flooding, in young and old successional plots. Richness and diversity decreased over time in upper and intermediate topographic positions, converging toward lesser values observed in lower positions. A transient peak in diversity occurred in lower topographic positions several years after flood disturbance. Species richness was similarly constrained by flooding stress and successional development. Thus, maximum diversity occurred at an early stage of succession in upper, infrequently flooded sites. Spatial and temporal patterns of plant diversity in this successional system did not generally conform with predictions from intermediate disturbance models. We propose that control of species diversity in old-field vegetation changed with time since flooding from physical stress to strong biotic interactions. Keywords: pampean grasslands, secondary succession, disturbance and stress gradients, species richness, vegetation structure.

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