Priority effects and desert anuran communities

2005 ◽  
Vol 83 (8) ◽  
pp. 1112-1116 ◽  
Author(s):  
G H Dayton ◽  
L A Fitzgerald
Keyword(s):  
Species Composition ◽  
Laboratory Experiments ◽  
Hatching Success ◽  
Aquatic Ecology ◽  
Priority Effects ◽  
Scaphiopus Couchii ◽  
Ephemeral Pools ◽  
Desert Regions ◽  
Community Assemblages ◽  
Current Paradigm

The roles of priority effects and predation in structuring anuran communities have not been considered important in desert environments characterized by highly ephemeral pools and anuran species that breed synchronously. Predation is one mechanism that can set the stage for priority effects to be important, especially in ephemeral pools where resources are limiting and densities are high. We observed oophagy by Scaphiopus couchii Baird, 1854 on eggs of Bufo speciosus Girard, 1854 in the field and conducted laboratory experiments to test the hypothesis that S. couchii tadpoles would reduce B. speciosus survivorship via predation. Three-day-old S. couchii tadpoles reduced hatching success of B. speciosus eggs by nearly 90%. When S. couchii and B. speciosus eggs were laid the same day, S. couchii tadpoles reduced B. speciosus egg survivorship by 56%. Our results indicate that priority effects and predation may play an important role in influencing species composition of anuran assemblages in desert regions. Our study provides more support for the need to reevaluate the current paradigm in aquatic ecology that suggests predation does not play a role in structuring community assemblages in highly ephemeral pools.

scholarly journals Priority Effects and Nonhierarchical Competition Shape Species Composition in a Complex Grassland Community

2019 ◽  
Vol 193 (2) ◽  
pp. 213-226 ◽  
Author(s):  
Lawrence H. Uricchio ◽  
S. Caroline Daws ◽  
Erin R. Spear ◽  
Erin A. Mordecai
Keyword(s):  
Species Composition ◽  
Priority Effects ◽  
Grassland Community

Desmids from ephemeral pools and aerophytic habitats from the Czech Republic

Biologia ◽  
2008 ◽  
Vol 63 (6) ◽  
Author(s):  
Jan Šťastný
Keyword(s):  
Czech Republic ◽  
Species Composition ◽  
Temporary Pools ◽  
Multivariate Statistic ◽  
The Czech Republic ◽  
Statistic Method ◽  
Ephemeral Pools ◽  
Different Types ◽  
Distribution And Ecology ◽  
Wetland Habitats

AbstractThe distribution and ecology of desmids in wetland habitats in the Czech Republic were studied during 2003–2007. Samples were taken also from various aerophytic habitats and temporary pools thet had not been sufficiently studied before. Altogether 110 desmids taxa were found in 31 samples which were ordinated on the basis of their desmid species composition using a multivariate statistic method. The discussion focuses on the most interesting findings and on the factors that influence the distribution of desmids in different types of aerophytic habitats.

scholarly journals The efficiency of nutrient utilization by permanent grassland in the Kameničky locality

2013 ◽  
Vol 61 (6) ◽  
pp. 1799-1806
Author(s):  
Adam Nawrath ◽  
Jakub Elbl ◽  
Antonín Kintl ◽  
Jaroslav Záhora ◽  
Jiří Skládanka
Keyword(s):  
Species Composition ◽  
Biomass Production ◽  
Laboratory Experiments ◽  
Plant Biomass ◽  
Grassland Management ◽  
Nutrient Utilization ◽  
Mineral Nitrogen ◽  
Permanent Grassland ◽  
The Difference ◽  
Plant Biomass Production

This work presents the analysis of the effect of grassland management on leaching of mineral nitrogen from rhizosphere and plant biomass production in area of our interest. The determined values show the influence of fertilization and species composition of permanent grassland on leaching of mineral nitrogen and biomass production. The values were determined during field and laboratory experiments. The highest availability of Nmin in the field experiment was detected in the variant N90+PK; the lowest availability of Nmin was recorded in the PK variant. The difference was statistically significant (P < 0.05). In the pot experiment, the highest loss of Nmin was recorded in the variant with N180+PK (16.88 mg.dm−3) with the difference being statistically significant as compared with the other variants (P < 0.05). Measured values of the availability of mineral nitrogen and plant biomass production indicate the importance of species composition at the establishment of new grassland. For example, species composition of permanent grassland has a great importance at the establishment of new grassland on erosion-affected soils in protection areas of drinking water. Because selected species of grasses can immobilize nitrogen in their bodies, thus preventing it’s leaching from the soil.

scholarly journals Priority effects and non-hierarchical competition shape species composition in a complex grassland community

2018 ◽  
Author(s):  
Lawrence H. Uricchio ◽  
S. Caroline Daws ◽  
Erin R. Spear ◽  
Erin A. Mordecai
Keyword(s):  
Species Composition ◽  
Exotic Species ◽  
Native Species ◽  
Complex Mixture ◽  
Single Species ◽  
Priority Effects ◽  
Complex Species ◽  
Species Dominance ◽  
Grassland Community ◽  
Population Dynamic Model

AbstractNiche and fitness differences control the outcome of competition, but determining their relative importance in invaded communities – which may be far from equilibrium – remains a pressing concern. Moreover, it is unclear whether classic approaches for studying competition, which were developed predominantly for pairs of interacting species, will fully capture dynamics in complex species assemblages. We parameterized a population dynamic model using competition experiments of two native and three exotic species from a grassland community. We found evidence for minimal fitness differences or niche differences between the native species, leading to slow replacement dynamics and priority effects, but large fitness advantages allowed exotics to unconditionally invade natives. Priority effects driven by strong interspecific competition between exotic species drove single-species dominance by one of two exotic species in 80% of model outcomes, while a complex mixture of non-hierarchical competition and coexistence between native and exotic species occurred in the remaining 20%. Fungal infection, a commonly hypothesized coexistence mechanism, had weak fitness effects, and is unlikely to substantially affect coexistence. In contrast to previous work on pairwise outcomes in largely native-dominated communities, our work supports a role for nearly-neutral dynamics and priority effects as drivers of species composition in invaded communities.

Effects of Calcium and pH on the Reproductive Success of Amnicola limosa (Gastropoda)

1990 ◽  
Vol 47 (9) ◽  
pp. 1694-1699 ◽  
Author(s):  
Margo A. Shaw ◽  
Gerry L. Mackie
Keyword(s):  
Reproductive Success ◽  
Embryonic Development ◽  
Water Chemistry ◽  
Laboratory Experiments ◽  
Calcium Concentration ◽  
Hatching Success ◽  
South Central ◽  
Naturally Occurring ◽  
Ph Range ◽  
The Relationship

Field and laboratory experiments were designed to examine the relationship between water chemistry (especially pH and calcium) and the reproductive success of Amnicola limosa. Fecundity (no. eggs∙female−1) was positively correlated with lake buffering capacity (P = 0.002) in naturally occurring populations. We documented a 66% reduction in fecundity in lakes over a pH range of 7.6–5.8. However, fecundity was higher than expected in a highly-coloured, low-pH lake. The number of juveniles produced per egg was not related to any water chemistry variable (multiple R2 = 0.186). A laboratory experiment demonstrated that pH, and not calcium, was limiting embryonic development. All embryos held at pH 4.5 failed to hatch. Eggs held at pH 5.5 experienced reduced hatching success (P = 0.013) and delayed development (P < 0.001) compared with those held at pH 6.5. Length of newly hatched snails did not differ significantly between treatments (P = 0.891). The critical calcium concentration required for embryonic development in laboratory incubation lay between 0.14 and 1.11 mg∙L−1. This is well below the calcium concentration of acidifying lakes in south-central Ontario.

scholarly journals Forest structure and species composition along a successional gradient of Lowland Atlantic Forest in Southern Brazil

2014 ◽  
Vol 14 (3) ◽  
Author(s):  
Márcia C.M. Marques ◽  
Victor P. Zwiener ◽  
Fernando M. Ramos ◽  
Marília Borgo ◽  
Renato Marques
Keyword(s):  
Species Composition ◽  
Atlantic Forest ◽  
Forest Structure ◽  
Forest Community ◽  
Secondary Forests ◽  
Lowland Forest ◽  
Successional Gradient ◽  
Successional Trajectory ◽  
Community Assemblages ◽  
Trees And Shrubs

The Lowland Forest is one of the most disturbed and fragile ecosystems in the Atlantic Forest biome, yet little is known regarding its successional trajectory and resilience. We evaluated changes in species assemblages and forest structure of the canopy and understory along a successional gradient (young 21-yrs old forest, immature 34-yrs old forest and late successional 59-yrs old forest) aiming to assess changes in species composition and successional trajectory of different strata of secondary forests. A 0.1 ha plot (ten 10x10 m sub-plots) from each forest stand was surveyed for trees and shrubs with a diameter at breast height (DBH) ≥ 4.8 cm (canopy) and for individuals with heights ≥ 1 m and DBH < 4.8 cm (understory). A total of 3,619 individuals from 82 plant species were sampled. The successional gradient was marked by a unidirectional increase in species richness and a bidirectional pattern of density changes (increasing from young to immature forest and decreasing from immature to late successional forest). Community assemblages were distinct in the three forests and two strata; indicator species were only weakly shared among stands. Thus, each successional forest and stratum was observed to be a unique plant community. Our results suggest slight predictability of community assemblages in secondary forests, but a relatively fast recovery of forest structure.

Effects of temperature and photoperiod on the duration of hatching, swimming, and copepodid survival of the parasitic copepod Salmincola edwardsii

1993 ◽  
Vol 71 (5) ◽  
pp. 972-976 ◽  
Author(s):  
David C. Conley ◽  
Mark A. Curtis
Keyword(s):  
Water Temperature ◽  
Brook Trout ◽  
Laboratory Experiments ◽  
Hatching Success ◽  
Salvelinus Fontinalis ◽  
Parasitic Copepod ◽  
Swimming Activity ◽  
The Other ◽  
Egg Hatching ◽  
Effects Of Temperature

We conducted laboratory experiments to test whether various temperature and photoperiod regimes had any effect on the duration of egg hatching, swimming activity, and copepodid survival in the parasitic copepod Salmincola edwardsii, commonly found on brook trout (Salvelinus fontinalis). Pairs of egg sacs were removed from adult female copepods; one of each pair was exposed to a different photoperiod than the other, at the same temperature. Experiments were conducted at 8, 12, 16, and 20 °C. Temperature had a significant effect on the duration of copepodid swimming activity and survival, and the onset of egg sac hatching was directly related to increasing water temperature. However, hatching duration and hatching success were not affected by temperature over the range tested. Photoperiod had no effect on hatching duration, hatching success, swimming activity, or copepodid survival. Our findings indicate that S. edwardsii copepodids can swim and survive for more than 2 weeks; much longer than the 2 days customarily reported in the literature. This must be accounted for in the development of strategies to control transmission.

A Preliminary Investigation of the Effects of Salinity on the Bacterial Flora of the Tay Estuary

1975 ◽  
Vol 75 (1-2) ◽  
pp. 137-144 ◽  
Author(s):  
R. A. Herbert
Keyword(s):  
Salt Stress ◽  
Species Composition ◽  
Laboratory Experiments ◽  
Bacterial Flora ◽  
Preliminary Investigation ◽  
Freshwater Bacteria ◽  
Tay Estuary

SynopsisTwo features of the effects of salinity on the bacterial flora of the Tay estuary are considered. First the effect of salinity on the size and species composition of the resident microfiora at various sites within the estuary. The second part is concerned with data obtained from laboratory experiments designed to study the effects of subjecting marine and freshwater bacteria, isolated from the Tay, to salt stress.

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