Co-existence, Demography and Distribution Patterns of Two Co-occurring Ecologically Equivalent Fynbos Proteaceae Species

1998 ◽  
Vol 46 (4) ◽  
pp. 505 ◽  
Author(s):  
J. J. Midgley ◽  
N. J. Enright ◽  
R. M. Cowling
Keyword(s):  
Interspecific Competition ◽  
Competitive Exclusion ◽  
Distribution Patterns ◽  
Size Class ◽  
Fire Intensity ◽  
Shallow Soil ◽  
Cape Peninsula ◽  
Rocky Habitats

Leucospermum conocarpodendron (L.) Beuk. and Mimetes fimbriifolius Salisb. ex J.Knight co-occur in the southern Cape Peninsula, where we studied their distribution patterns, demography and fire responses. Leucospermum conocarpodendron has relatively larger seedlings and is therefore the likely competitive dominant. Adults and seedlings of both species are widely spaced and interspecific competition is unlikely to cause competitive exclusion. Differences between the two species in recruitment levels and fire-mortality are small. Thus their size-class distributions are very similar. They are restricted to shallow-soil rocky habitats, not only because of reduced fire intensity in these sites, but because these are habitats avoided by the faster growing more competitive reseeding Proteaceae. Co-existence of these two species appears to mainly be due to fire keeping populations sparse, and ants keeping individuals fairly isolated.

scholarly journals The Effects of Water Levels and Interspecific Competition on Two Carex Species in a Temperate Wetland of Northeast China

2020 ◽  
Vol 12 (24) ◽  
pp. 10654
Author(s):  
Wenwen Tan ◽  
Li Sun ◽  
Xinhou Zhang ◽  
Changchun Song
Keyword(s):  
Spatial Distribution ◽  
Water Level ◽  
Interspecific Competition ◽  
Distribution Patterns ◽  
Wetland Plants ◽  
Water Levels ◽  
Carex Lasiocarpa ◽  
Temperate Wetland ◽  
The Relationship ◽  
Spatial Distribution Characteristic

Zonation along a water level is the main spatial distribution characteristic of wetland plants. This is mainly because of the influences of hydrological conditions and interspecific competition, which finally narrow the fundamental niche of a species to its realized niche. In the present study, a controlled experiment was conducted in order to analyze the relationship between Carex lasiocarpa/Carex pseudocuraica and Glyceria spiculosa, in conditions of three competitive treatments at four water levels. The results showed that in no competition, C. lasiocarpa preferred low water levels, but this preference receded when competing with G. spiculosa. In contrast, C. pseudocuraica had greater preference for low water level when competing with G. spiculosa. The root/shoot ratios of the two Carex species decreased with increasing water levels, but they were almost unaffected by different competition treatments. With the increase in water level during full competition with G. spiculosa, the competitive ability of C. lasiocarpa showed an increasing trend, whereas a contrary trend was observed in C. pseudocuraica. Our results suggested the effects of water levels and their interactions with interspecific competition varied between the two Carex species and played an important role in determining spatial distribution patterns and potential community succession of wetland plants.

Spatial and temporal variability in the distribution and diet of the gudgeon (Eleotridae: Hypseleotris spp.) in a subtropical Australian reservoir

2003 ◽  
Vol 54 (8) ◽  
pp. 1009 ◽  
Author(s):  
Shaun N. Meredith ◽  
Vladimir F. Matveev ◽  
Paul Mayes
Keyword(s):  
Temporal Variability ◽  
Class Group ◽  
Competitive Exclusion ◽  
Size Class ◽  
Spatial And Temporal Variability ◽  
Adult Fish ◽  
Size Classes ◽  
Diurnal Cycles ◽  
Diurnal Distribution ◽  
Near Shore

The diurnal distribution and diet of Hypseleotris spp. was examined over a 14-month period in Maroon Dam, a productive subtropical reservoir in south-east Queensland, Australia. Three distinct size classes of Hypseleotris were observed. The smallest (<16 mm standard length (SL)) fish undertake a vertical diurnal migration in the pelagic throughout the year, spending daylight hours near the surface and night hours in deeper waters. The diet of this size class consists almost exclusively of zooplankton (98.6% total prey volume), with cladocera and copepoda dominating the identifiable prey items. A larger (12–20 mm SL) size class group of subadult/adult fish occupies the near-shore littoral throughout the daylight hours but moves out of the sampled area during the night. The diet of this size class is more diverse (zooplankton 58.5%, macro-invertebrate 25.0%, other 16.5%). The largest size class (>20 mm SL) of adult Hypseleotris remains in the near-shore littoral throughout seasonal and diurnal cycles and has a more eclectic diet than the other two size classes (zooplankton 28.8%, macro-invertebrate 28.9%, other 42.3%). Spatial and temporal differences in the distribution and diet of these three size class groups are discussed with reference to the abundance and availability of suitable prey, intraspecific competitive exclusion, predator avoidance and water quality.

Abundance/host size relationship in a fish trematode community

1992 ◽  
Vol 66 (3) ◽  
pp. 187-192 ◽  
Author(s):  
A. Saad-Fares ◽  
C. Combes
Keyword(s):  
Interspecific Competition ◽  
Digestive Tract ◽  
Host Species ◽  
Size Class ◽  
Host Size ◽  
Trematode Species ◽  
High Threshold ◽  
East Mediterranean ◽  
Host Growth ◽  
Single Host

ABSTRACTThe abundance of six species of trematodes: Aphanurus stossichi, Bacciger israelensis, Diphterostomum israelense, Plagioporus idoneus, Lepocreadium album and L. pegorchis, parasitic in the digestive tract of marine teleostei (Sparidae) collected near Jounieh (east Mediterranean), was analysed as a function of the host-size. In two parasite/host systems, infections were observed from the lowest size classes of the sample, with a clear tendency to an increase of abundance in older fish. In four others, parasites appear only above a rather high threshold class, young individuals never being infected. In the last three parasite/host systems, host invasion may occur early or late, but infection decreases above a well defined size class, old fishes rarely or never being infected. A given trematode species. when parasitizing several host species, shows similar abundance/host size relationships, e.g. P. idoneus in Diplodus vulgaris and Oblada melanura. When more than one species of trematode infects a single host species, curves can be markedly distinct; for instance, L. pegorchis was collected from Pagellus erythrinus below 15 cm. whereas D. israelense parasitized the same fish approximately above the same size. There is no evidence that such a replacement of one trematode by another in the course of host growth is a result of interspecific competition.

scholarly journals Evidence of character displacement in microhabitat use between two tropical sympatric Holcosus lizard species (Reptilia, Teiidae)

2019 ◽  
pp. 379-388
Author(s):  
F. Ruiz Real ◽  
J. Martín
Keyword(s):  
Interspecific Competition ◽  
Competitive Exclusion ◽  
Species Coexistence ◽  
Character Displacement ◽  
Sympatric Species ◽  
The Other ◽  
Microhabitat Use ◽  
Lizard Species ◽  
Species Shifts ◽  
Selection Of

Interspecific competition between sympatric related species leading to character displacement is critical for species coexistence, especially in tropical habitats. We examined microhabitat use of two sympatric species of tropical lizards of the genus Holcosus in relationship to the microhabitats available in two ecosystems. The species H. festivus lives exclusively in the forest and uses microhabitats in proportion to their availability; while the other, H. quadrilineatus, lives both in forest and on the beach and selects microhabitats with specific characteristics. In the ecosystem where these two lizards live in sympatry (forest), we observed a differential microhabitat use between the two species. However, these differences indicated changes in habitat use by H. quadrilineatus (the smaller species) concerning its patterns of habitat selection in the ecosystem (beach) where only this species occurs. The age of the lizards did not affect the patterns of selection of microhabitats of either species. Shifts in microhabitat use may allow coexistence in sympatry of both species, which might result from the competitive exclusion of the smaller species by the larger species. Key words: Interspecific competition, Holcosus, Lizards, Microhabitat use, Tropical habitats

scholarly journals The role of root buds in the regeneration of Casearia sylvestris Swartz (Salicaceae) in the cerrado, São Carlos, São Paulo state, Brazil

Hoehnea ◽  
2014 ◽  
Vol 41 (3) ◽  
pp. 345-352 ◽  
Author(s):  
Maristela Imatomi ◽  
João Paulo Souza ◽  
Sonia Cristina Juliano Gualtieri ◽  
Alfredo Gui Ferreira
Keyword(s):  
Spatial Distribution ◽  
Distribution Patterns ◽  
Fire Effects ◽  
Size Class ◽  
Paulo State ◽  
Casearia Sylvestris ◽  
Underground System ◽  
Burnt Areas ◽  
Root Buds

The present work describes the fire effects on the population structure of Casearia sylvestris Swartz (Salicaceae). Diameter and height structure as well as spatial distribution patterns of the root sprouts were analyzed pre- and post-fire. The morphology and anatomy of the underground system were also analyzed in order to investigate the nature and origin of sprouts from this system. In this study, a 10-ha of Cerrado area was sampled from February to November 2006; in August, a fire burned roughly 80% of the study area, allowing us to compare the data collected pre- and post-fire. Our findings show that the underground systems consisted of specialized roots and buds originated close to the vascular cambium. The spatial distribution of the root sprouts became clustered pre- and post-fire and most of the root sprouts were concentrated in the first size class, indicating that the sprouts from roots play an important role in the recovery of this species in burnt areas.

Distribution patterns and interthalline interactions of epiphytic foliose lichens

1992 ◽  
Vol 70 (4) ◽  
pp. 818-823 ◽  
Author(s):  
Elizabeth John
Keyword(s):  
Key Words ◽  
Interspecific Competition ◽  
Distribution Patterns ◽  
Nearest Neighbour ◽  
Tree Trunk ◽  
Ecological Strategies ◽  
Interspecific Differences ◽  
Flavoparmelia Caperata ◽  
Competition For Resources ◽  
Epiphyte Community

The foliose lichens of a corticolous epiphyte community were sampled using a grid of points and nearest neighbour sampling. Most species were found to have nonrandom distributions with respect to height and aspect on the tree trunk. The tendency of species to form exclusive patches and to contact other species showed large interspecific differences. Some formed monocultures and had fewer interspecific contacts than expected, while others did not form large patches and had more interspecific contacts than expected. Investigation of interspecific thallus overlaps revealed a hierarchy in which heavier species such as Flavoparmelia caperata (2.3 mg/mm2) overtop lighter ones such as Melanelia subaurifera (1.1 mg/mm2) more often than the converse is true. It is likely that being overtopped by another lichen puts a thallus at a disadvantage in competition for resources. The success of a species at overtopping another does not change according to location on the tree trunk. There was evidence that F. caperata excluded other species during succession. Key words: epiphytes, foliose lichens, thallus overlaps, interspecific competition, ecological strategies.

scholarly journals A mechanistic model of the S-shaped population growth

2014 ◽  
Author(s):  
Lev V. Kalmykov
Keyword(s):  
Cellular Automata ◽  
Population Growth ◽  
Interspecific Competition ◽  
Competitive Exclusion ◽  
Mechanistic Model ◽  
Main Idea ◽  
Exclusion Principle ◽  
Cellular Automata Model ◽  
Competitive Exclusion Principle ◽  
Spatio Temporal

The main idea of this note is to show the most basic and purely mechanistic model of population growth, which has been used by us to create models of interspecific competition for verification of the competitive exclusion principle (1, 2). Our logical deterministic individual-based cellular automata model demonstrates a spatio-temporal mechanism of the S-shaped population growth.

scholarly journals EFEK KERAGAMAN TIPE HABITAT TERHADAP STRUKTUR POPULASI DAN MORFOMETRIK ABALON HALIOTIS ASININA LINNAEUS, 1758

2020 ◽  
Vol 20 (1) ◽  
pp. 29
Author(s):  
Ermayanti Ishak ◽  
Isdradjad Setyobudiandi ◽  
Fredinan Yulianda ◽  
Mennofatria Boer ◽  
Bahtiar Bahtiar
Keyword(s):  
Growth Parameters ◽  
Strong Relationship ◽  
Growth Patterns ◽  
Size Class ◽  
Regression Equations ◽  
Growth Data ◽  
Habitat Types ◽  
Haliotis Asinina ◽  
Rocky Habitats ◽  
The Relationship

Abstrak:  Abalon (H.asinina) adalah kelompok gastropoda laut bernilai komersial dan tersebar di perairan Soropia Sulawesi Tenggara.  H. asinina menyukai tipe habitat khusus, seperti habitat berbatu yang ditumbuhi alga dan habitat padang lamun. Bokori dan Toronipa mewakili 2 tipe habitat khusus tersebut yang lokasinya berada di perairan Soropia. Penelitian bertujuan untuk mengkaji pertumbuhan populasi abalon (H. asinina) pada habitat yang berbeda melalui hubungan dimensi morfometrik, faktor kondisi, dan komposisi kelompok ukuran. Data pertumbuhan dianalisis dengan persamaan regresi non linier menggunakan program data analisis dalam MS. Excel 2010. Hubungan antara L dengan Wt dan L dengan Lc di 2 lokasi menunjukkan hubungan yang positif dan kuat (R2 < 70%), sedangkan hubungan antara L dengan dimensi lainnya seperti Bc, Tc, Lc, dan Vc menunjukkan hubungan yang lemah.  Pola pertumbuhan di Bokori terdiri atas pertumbuhan isometrik dan alometrik negatif, sedangkan Toronipa, pola pertumbuhannya alometrik negatif.   Faktor kondisi rata-rata berfluktuasi setiap bulan dengan nilai tertinggi di Bokori. Perairan Bokori didominasi oleh persentase kelompok juvenil sebesar 52.22% pada kelas ukuran 27.4-49.62 mm. Toronipa didominasi oleh persentase kelompok dewasa sebesar 66.67% pada kelas ukuran 50.62-84.42 mm. Keragaman tipe habitat memengaruhi parameter pertumbuhan abalon (H.asinina). Hasil penelitian diharapkan menjadi informasi penting bagi upaya merumuskan pengelolaan sumber daya abalon yang tepat.Kata Kunci: Keragaman Habitat, Pertumbuhan, H. asinina, Morfometrik, Struktur PopulasiAbstract: Abalone (Haliotis asinina) is a marine gastropod which has commercial value. Abalone spread in the waters of Soropia, Southeast Sulawesi.  H. asinina likes special habitat types, such as rocky habitats overgrown with algae and seagrass habitats. Bokori and Toronipa represent these two special habitat types which are located in Soropia waters. The study aims to assess the growth of abalone (H. asinina) populations in different habitats through the relationship of morphometric dimensions, condition factors, and composition of size groups.  Growth data were analyzed by non-linear regression equations using data analysis programs in MS. Excel 2010.  The relationship between L with Wt and L with Lc at 2 locations shows a positive and strong relationship (R2 <70%), while the relationship between L and other dimensions such as Bc, Tc, Lc, and Vc shows a weak relationship.  Growth patterns in Bokori consist of isometric and allometric negative growths, while Toronipa, the pattern of negative allometric growth. The average condition factor fluctuates in each month of observation and the highest in Bokori.  Bokori waters are dominated by percentage of juvenile groups of 52.22%  in the size class of 27.4-49.62 mm. Toronipa is dominated by adult or broodstock abalone of 66.67% in the size class of 50.62-84.42 mm.  Toronipa is dominated by the percentage of the adult group at 66.67% in the size class of 50.62-84.42 mm. The diversity of habitat types affects the growth parameters of abalone (H.asinina).  The results of study are expected to be important information for efforts to formulate appropriate abalone resource management.Keywords: Diversity of Habitat, Growth, H. asinina, Morphometric, Population structure

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