Predator Species Richness and Prey Population Variability: Effects on Diets of Benthic Stream Fishes

1986 ◽  
Vol 115 (1) ◽  
pp. 63 ◽  
Author(s):  
Michael J. Hansen ◽  
Steven P. Gloss ◽  
Barbara L. Peckarsky
Keyword(s):  
Species Richness ◽  
Population Variability ◽  
Prey Population ◽  
Stream Fishes ◽  
Predator Species ◽  
Benthic Stream

scholarly journals Interference competition pressure predicts the number of avian predators that shifted their timing of activity

2018 ◽  
Vol 285 (1880) ◽  
pp. 20180744 ◽  
Author(s):  
Yifan Pei ◽  
Mihai Valcu ◽  
Bart Kempenaers
Keyword(s):  
Species Richness ◽  
Body Size ◽  
Interference Competition ◽  
Relative Importance ◽  
Exploitation Competition ◽  
Predator Species ◽  
Avian Predator ◽  
Avian Predators ◽  
Time Partitioning ◽  
Competition Pressure

Being active at different times facilitates the coexistence of functionally similar species. Hence, time partitioning might be induced by competition. However, the relative importance of direct interference and indirect exploitation competition on time partitioning remains unclear. The aim of this study was to investigate the relative importance of these two forms of competition on the occurrence of time-shifting among avian predator species. As a measure of interference competition pressure, we used the species richness of day-active avian predator species or of night-active avian predator species (i.e. species of Accipitriformes, Falconiformes and Strigiformes) in a particular geographical area (assemblage). As an estimate of exploitation competition pressure, we used the total species richness of avian predators in each assemblage. Estimates of the intensity of interference competition robustly predicted the number of Accipitriformes species that became crepuscular and the number of Strigiformes species that became day-active or strictly crepuscular. Interference competition pressure may depend on body size and on the total duration of the typical active period (day or night length). Our results support—to some extent—that smaller species are more likely to become time-shifters. Day length did not have an effect on the number of time-shifter species in the Accipitriformes. Among the large Strigiformes, more time-shifter species occur in areas where nights are shorter (i.e. where less of the typical time resource is available). However, in the small Strigiformes, we found the opposite, counterintuitive effect: more time-shifters where nights are longer. Exploitation competition may have had an additional positive effect on the number of time-shifters, but only in Accipitriformes, and the effect was not as robust. Our results thus support the interference competition hypothesis, suggesting that animals may have shifted their time of activity, despite phylogenetic constraints on the ability to do so, to reduce the costs of direct interactions. Our findings also highlight the influence of body size as a surrogate of competitive ability during encounters on time partitioning, at least among avian predators.

scholarly journals Reduced predator species richness drives the body gigantism of a frog species on the Zhoushan Archipelago in China

2010 ◽  
Vol 80 (1) ◽  
pp. 171-182 ◽  
Author(s):  
Yiming Li ◽  
Feng Xu ◽  
Zhongwei Guo ◽  
Xuan Liu ◽  
Changnan Jin ◽  
...  
Keyword(s):  
Species Richness ◽  
The Body ◽  
Predator Species ◽  
Frog Species ◽  
Zhoushan Archipelago

A PREY-PREDATOR MODEL WITH DIFFUSION AND A SUPPLEMENTARY RESOURCE FOR THE PREY IN A TWO‐PATCH ENVIRONMENT

2005 ◽  
Vol 9 (1) ◽  
pp. 9-24 ◽  
Author(s):  
J. Dhar
Keyword(s):  
Steady State ◽  
Asymptotic Stability ◽  
Prey Species ◽  
Steady State Solution ◽  
State Solution ◽  
Prey Population ◽  
Predator Species ◽  
Additional Resource ◽  
Linear And Nonlinear ◽  
Predator Model

In this paper, a prey‐predator dynamics, where the predator species partially depends upon the prey species, in a two patch habitat with diffusion and there is a non‐diffusing additional resource for the prey population, is modeled and analyzed. It is shown, that there exists a positive, monotonic, continuous steady state solution with continuous matching at the interface for both the species separately. Further, we obtain conditions for asymptotic stability for both linear and nonlinear cases. Šiame straipsnyje modeliuojama ir analizuojama plešr‐unu ir auku dinamika, laikant, kad plešr-unu populiacija dalinai priklauso nuo auku skačiaus. Areala sudaro dvi sritys, kuriose vyksta populiaciju individu difuzija, be to, aukoms yra išskirtas nedifunduojantis resursas. Irodyta, kad egzistuoja teigiamas, monotoniškas, tolydus stacionarusis sprendinys, tenkinantis tolydumo salyga abiems populiacijoms atskirai. Gautos asimptotinio stabilumo salygos tiesiniu ir netiesiniu atvejais.

scholarly journals Association between predator species richness and human hantavirus infection emergence in Brazil

One Health ◽  
2020 ◽  
Vol 11 ◽  
pp. 100196
Author(s):  
Kyung-Duk Min ◽  
Maria Cristina Schneider ◽  
Sung-il Cho
Keyword(s):  
Species Richness ◽  
Hantavirus Infection ◽  
Predator Species

scholarly journals Wildlife-Friendly Livestock Management Promotes Mammalian Biodiversity Recovery on a Semi-Arid Karoo Farm in South Africa

2021 ◽  
Vol 2 ◽  
Author(s):  
Matthew P. E. Schurch ◽  
Jeannine McManus ◽  
Stefan Goets ◽  
Lain E. Pardo ◽  
David Gaynor ◽  
...  
Keyword(s):  
South Africa ◽  
Species Richness ◽  
Relative Abundance ◽  
Positive Impact ◽  
Mammalian Species ◽  
Biodiversity Loss ◽  
Livestock Grazing ◽  
Predator Species ◽  
Livestock Farm ◽  
Number Of Species

Agriculture is an essential production system used to feed the growing human population, but at the same time has become a major driver of biodiversity loss and environmental degradation. Employing production methods that restore degraded landscapes can have a positive impact on biodiversity, whilst improving food production. We assessed how mammalian biodiversity, specifically richness and their relative abundances varied on five Karoo farms in South Africa that had been amalgamated and subjected to a transition from traditional livestock grazing techniques (sporadic rotational grazing and lethal predator control) to wildlife-friendly non-lethal predator management, using human shepherding of livestock under a high-density short-duration grazing regime. We used camera trap data collected over a 4-year period, to measure mammalian species richness, distribution and relative abundance on the wildlife-friendly farm to investigate temporal changes throughout the conversion from traditional farming practices. In the last year of the study (2019) additional cameras were used to provide a spatial comparison of mammalian species on the wildlife-friendly farm to two neighboring farms, a traditional livestock farm using lethal predator controls, and a game farm. We found that mammalian species richness increased year on year resulting in a significant increase of 24% over the duration of the study. Herbivores showed an increase of 33% in the number of species detected over the years, while predator species increased by 8%. The relative abundance and distribution of most species also showed increases as the conversion process took place. For example, 73% of the herbivore species detected throughout the study increased in their relative abundance. Similarly, 67% of all species showed an increase in the number of sites occupied over the years. In the final year of the study the wildlife-friendly farm had more mammalian species compared to the game farm and traditional livestock farm, with the latter two sites having a similar number of species when compared to the commencement of the conversion of the wildlife-friendly site. These broad improvements in mammalian biodiversity demonstrate that livestock production can benefit local mammalian biodiversity through a combination of herder grazing management and wildlife-friendly farming.

scholarly journals Trophic structure stability and extinction dynamics of beetles (Coleoptera) in tropical forest fragments

1998 ◽  
Vol 353 (1367) ◽  
pp. 437-451 ◽  
Author(s):  
R. K. Didham ◽  
J. H. Lawton ◽  
P. M. Hammond ◽  
P. Eggleton
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Tropical Forest ◽  
Forest Fragmentation ◽  
Trophic Structure ◽  
Forest Edge ◽  
Forest Fragments ◽  
Trophic Groups ◽  
Predator Species ◽  
Extinction Probabilities

A first analysis of the stability of trophic structure following tropical forest fragmentation was performed in an experimentally fragmented tropical forest landscape in Central Amazonia. A taxonomically and trophically diverse assemblage of 993 species of beetles was sampled from 920 m 2 of leaf litter at 46 sites varying in distance from forest edge and fragment area. Beetle density increased significantly towards the forest edge and showed non-linear changes with fragment area, due to the influx of numerous disturbed-area species into 10 ha and 1 ha fragments. There was a marked change in species composition with both decreasing distance from forest edge and decreasing fragment area, but surprisingly this change in composition was not accompanied by a change in species richness. Rarefied species richness did not vary significantly across any of the sites, indicating that local extinctions of deep forest species were balanced by equivalent colonization rates of disturbed-area species. The change in species composition with fragmentation was non-random across trophic groups. Proportions of predator species and xylophage species changed significantly with distance from forest edge, but no area-dependent changes in proportions of species in trophic groups were observed. Trophic structure was also analysed with respect to proportions of abundance in six trophic groups. Proportions of abundance of all trophic groups except xylomycetophages changed markedly with respect to both distance from forest edge and fragment area. Local extinction probabilities calculated for individual beetle species supported theoretical predictions of the differential susceptibility of higher trophic levels to extinction, and of changes in trophic structure following forest fragmentation. To reduce random effects due to sampling error, only abundant species ( n ≥ 46) were analysed for extinction probabilities, as defined by absence from samples. Of these common species, 27% had significantly higher probabilities of local extinction following fragmentation. The majority of these species were predators; 42% of all abundant predator species were significantly more likely to be absent from samples in forest fragments than in undisturbed forest. These figures are regarded as minimum estimates for the entire beetle assemblage because rarer species will inevitably have higher extinction probabilities. Absolute loss of biodiversity will affect ecosystem process rates, but the differential loss of species from trophic groups will have an even greater destabilizing effect on food web structure and ecosystem function.

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