The effect of preservation on diversity in a Triassic reef basin assemblage

2021 ◽  
Author(s):  
Vanessa Julie Roden ◽  
Alexander Nützel ◽  
Wolfgang Kiessling
Keyword(s):  
Biotic Interactions ◽  
Priority Effects ◽  
Late Triassic ◽  
Strong Increase ◽  
Predator Prey ◽  
Cassian Formation ◽  
Tropical Reef ◽  
Fossil Assemblages ◽  
Benthic Ecosystems ◽  
High Beta

<p>Taphonomic effects complicate the assessment of variations in biodiversity over time. Most pre-Cenozoic fossil assemblages have been altered through taphonomic effects, such as lithification and aragonite dissolution. Several studies have found alpha (local) and gamma (global) diversity in marine ecosystems to be low in the early Mesozoic and then increase throughout the Mesozoic, reaching a maximum in the Cenozoic.</p><p>The Middle to Late Triassic Cassian Formation, exposed in the Dolomites, Southern Alps, northern Italy, comprises tropical reef basin and transported platform assemblages characterized by high diversity and commonly excellent preservation of fossils. The Cassian Formation yields high alpha (mean species richness per locality: 96), beta (mean Jaccard dissimilarity: 0.95), and gamma (1421 invertebrate species) diversity. The high primary diversity is probably due to the tropical reef-associated setting, and its reduced taphonomic alteration caused 4.5 times higher biodiversity to be preserved than in comparable pre-Cenozoic settings. High beta diversity can be explained by the presence of various habitat types and may also have been driven by priority effects. The Cassian fauna, like most comparable modern ecosystems, features a large number of gastropods (39% of all invertebrates, 58% of mollusks are gastropods). Especially small species in the millimeter size range contribute to the large number of gastropod species in the Cassian Formation. Our results support the assumption that the Modern Evolutionary Fauna was already established early in the Mesozoic and that the scarcity of small gastropods in many fossil assemblages is a taphonomic phenomenon. This contradicts the view that the major radiation of gastropods and the generally very strong increase in biodiversity largely took place in the Cenozoic. We suggest that highly complex, gastropod-dominant marine benthic ecosystems are as old as Middle/Late Triassic, pointing to an earlier establishment of the Modern Evolutionary Fauna than previously assumed. An improved eco-space utilization by infaunalization and increased biotic interactions such as a predator/prey escalation may have contributed to the high biodiversity and may reflect early aspects of the Marine Mesozoic Revolution.</p>

scholarly journals Drivers of beta diversity in modern and ancient reef-associated soft-bottom environments

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9139
Author(s):  
Vanessa Julie Roden ◽  
Martin Zuschin ◽  
Alexander Nützel ◽  
Imelda M. Hausmann ◽  
Wolfgang Kiessling
Keyword(s):  
Water Depth ◽  
Beta Diversity ◽  
Environmental Gradients ◽  
Priority Effects ◽  
Spatial Distance ◽  
Late Triassic ◽  
Minor Role ◽  
Compositional Variation ◽  
Soft Bottom ◽  
Cassian Formation

Beta diversity, the compositional variation among communities, is often associated with environmental gradients. Other drivers of beta diversity include stochastic processes, priority effects, predation, or competitive exclusion. Temporal turnover may also explain differences in faunal composition between fossil assemblages. To assess the drivers of beta diversity in reef-associated soft-bottom environments, we investigate community patterns in a Middle to Late Triassic reef basin assemblage from the Cassian Formation in the Dolomites, Northern Italy, and compare results with a Recent reef basin assemblage from the Northern Bay of Safaga, Red Sea, Egypt. We evaluate beta diversity with regard to age, water depth, and spatial distance, and compare the results with a null model to evaluate the stochasticity of these differences. Using pairwise proportional dissimilarity, we find very high beta diversity for the Cassian Formation (0.91 ± 0.02) and slightly lower beta diversity for the Bay of Safaga (0.89 ± 0.04). Null models show that stochasticity only plays a minor role in determining faunal differences. Spatial distance is also irrelevant. Contrary to expectations, there is no tendency of beta diversity to decrease with water depth. Although water depth has frequently been found to be a key factor in determining beta diversity, we find that it is not the major driver in these reef-associated soft-bottom environments. We postulate that priority effects and the biotic structuring of the sediment may be key determinants of beta diversity.

scholarly journals The Biodiversity of Water Mites That Prey on and Parasitize Mosquitoes

Diversity ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 226
Author(s):  
Adrian A. Vasquez ◽  
Bana A. Kabalan ◽  
Jeffrey L. Ram ◽  
Carol J. Miller
Keyword(s):  
Mosquito Species ◽  
Biotic Interactions ◽  
Future Research ◽  
Water Mites ◽  
Ecological Functions ◽  
Predator Prey ◽  
Parasitic Mite ◽  
Aquatic Food ◽  
Parasitic Interactions ◽  
Mite Predator

Water mites form one of the most biodiverse groups within the aquatic arachnid class. These freshwater macroinvertebrates are predators and parasites of the equally diverse nematocerous Dipterans, such as mosquitoes, and water mites are believed to have diversified as a result of these predatory and parasitic relationships. Through these two major biotic interactions, water mites have been found to greatly impact a variety of mosquito species. Although these predatory and parasitic interactions are important in aquatic ecology, very little is known about the diversity of water mites that interact with mosquitoes. In this paper, we review and update the past literature on the predatory and parasitic mite–mosquito relationships, update past records, discuss the biogeographic range of these interactions, and add our own recent findings on this topic conducted in habitats around the Laurentian Great Lakes. The possible impact on human health, along with the importance of water mite predator–prey dynamics in aquatic food webs, motivates an increase in future research on this aquatic predator and parasite and may reveal novel ecological functions that these parasitic and predator–prey relationships mediate.

scholarly journals A fish-eye view on the new Arctic lightscape

2015 ◽  
Vol 72 (9) ◽  
pp. 2532-2538 ◽  
Author(s):  
Øystein Varpe ◽  
Malin Daase ◽  
Trond Kristiansen
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Predator Prey ◽  
Statistical Correlations ◽  
Ecological Relationships ◽  
Complex Processes ◽  
Arctic Climate Change ◽  
Benthic Ecosystems

Abstract A gigantic light experiment is taking place in the Arctic. Climate change has led to substantial reductions in sea ice extent and thickness in the Arctic Ocean. Sea ice, particularly when snow covered, acts as a lid hindering light to reach the waters underneath. Less ice will therefore mean more light entering the water column, with profound effects on pelagic and benthic ecosystems. Responses through primary production are so far well acknowledged. Here we argue that there is a need to broaden the view to include light-driven effects on fish, as they depend on light to locate prey. We used the Norwegian Earth System Model estimates of past and future sea ice area and thickness in the Arctic and applied attenuation coefficients for ice and snow to estimate light intensity. The results show a dramatic increase in the amount of light predicted to reach the future Arctic Ocean. We combined this insight with mechanistic understanding of how light modulates visual prey-detection and predict that fish will forage more efficiently as sea ice diminishes and that their populations will expand to higher latitudes, at least seasonally. Poleward shifts of boreal fish species have been predicted by many and to some extent observed, but a changing light environment has so far not been considered a driver. Expanding distributions and greater visual predation may restructure ecological relationships throughout the Arctic foodweb and lead to regime shifts. Research efforts should focus on the dynamics of how less sea ice will affect the feeding ecology and habitat usage of fish, particularly the northern limits of distributions. Mechanistic approaches to these topics offer insights beyond statistical correlations and extrapolations, and will help us understand how changing biophysical dynamics in the Arctic influence complex processes including production, predator–prey interactions, trait-evolution, and fisheries.

The direct and indirect effects of temperature on a predator–prey relationship

2001 ◽  
Vol 79 (10) ◽  
pp. 1834-1841 ◽  
Author(s):  
Michael T Anderson ◽  
Joseph M Kiesecker ◽  
Douglas P Chivers ◽  
Andrew R Blaustein
Keyword(s):  
Indirect Effects ◽  
Prey Capture ◽  
Prey Size ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Predator Prey ◽  
Prey Mass ◽  
Effects Of Temperature ◽  
Logistic Regression Equation ◽  
Probability Of Capture

Abiotic factors may directly influence community structure by influencing biotic interactions. In aquatic systems, where gape-limited predators are common, abiotic factors that influence organisms' growth rates potentially mediate predator–prey interactions indirectly through effects on prey size. We tested the hypothesis that temperature influences interactions between aquatic size-limited insect predators (Notonecta kirbyi) and their larval anuran prey (Hyla regilla) beyond its indirect effect on prey size. Notonecta kirbyi and H. regilla were raised and tested in predator–prey trials at one of three experimentally maintained temperatures, 9.9, 20.7, or 25.7°C. Temperature strongly influenced anuran growth and predator success; mean tadpole mass over time was positively related to temperature, while the number of prey caught was negatively related. At higher temperatures tadpoles attained greater mass more quickly, allowing them to avoid capture by notonectids. However, the probability of capture is a function of both mass and temperature; temperature was a significant explanatory variable in a logistic regression equation predicting prey capture. For a given prey mass, tadpoles raised in warmer water experienced a higher probability of capture by notonectids. Thus, rather than being static, prey size refugia are influenced directly by abiotic factors, in this case temperature. This suggests that temperature exerts differential effects on notonectid and larval anurans, leading to differences in the probability of prey capture for a given prey mass. Therefore, temperature can influence predator–prey interactions via indirect effects on prey size and direct effects on prey.

Brazil nut fruit capsules as phytotelmata: interactions among anuran and insect larvae

1993 ◽  
Vol 71 (6) ◽  
pp. 1193-1201 ◽  
Author(s):  
Janalee P. Caldwell
Keyword(s):  
Priority Effects ◽  
Brazil Nut ◽  
Insect Larvae ◽  
Experimental Conditions ◽  
Lowland Tropical Forest ◽  
Predator Prey ◽  
Structured Systems ◽  
Species Survival ◽  
Fallen Fruit ◽  
Amazonian Brazil

Under experimental conditions, body size, and thus indirectly priority effects, determines the outcome of predator–prey interactions among the aquatic larvae of a small assemblage of anuran and insect species using a patchily distributed microcosm. This assemblage occurs naturally in fallen fruit capsules of the Brazil nut tree, Bertholletia excelsa (family Lecythidaceae), in lowland tropical forest in Amazonian Brazil. Three of the species (the tadpole of a poison frog and the larvae of a giant damselfly and a culicid mosquito) are predators in the system and form a guild in which all are capable of feeding mutually on smaller individuals of the other two species. The larvae of the two insects are also cannibalistic, although the tadpole is not. Predator–prey experiments among certain pairs of these three species revealed size-related intra-guild predation. The results of these experiments and observations on naturally occurring capsules indicate that only one individual of any species per fruit capsule will survive to adulthood. Field-sampled capsules revealed low densities of guild members, with few co-occurrences among them. Whether this is due to the timing of the study in the early part of the rainy season or some other factor limiting accessibility to the fruit capsules is unknown. Although priority effects are well known among assemblages of competitors, this study reveals that potentially they can significantly affect predator-structured systems. The larva of a fourth species in the assemblage, a small bufonid toad, is detritivorous and palatable to the three predaceous species. In the presence of one of the three predaceous species, survival of the bufonid larvae depends on a rapid time to metamorphosis and on saturation of the microcosm with enough individuals in a clutch that some will survive to metamorphosis.

Growth in encrusting cheilostome bryozoans: I. Evolutionary trends

Paleobiology ◽  
1989 ◽  
Vol 15 (3) ◽  
pp. 255-282 ◽  
Author(s):  
Scott Lidgard ◽  
Jeremy B. C. Jackson
Keyword(s):  
Morphological Evolution ◽  
Biotic Interactions ◽  
Basic Element ◽  
Fossil Species ◽  
Long Duration ◽  
Long Term Trends ◽  
Fossil Assemblages ◽  
Ecological Dominance ◽  
Cheilostome Bryozoans

Growth of the colony is a basic element of morphological evolution and life history in cheilostome bryozoans. Here we consider the occurrence of different modes of growth in encrusting cheilostomes through geologic time and in well-studied living associations. We assess patterns of zooid formation by direct examination of skeletal characters in species from nearly all diverse fossil assemblages reported from North America and quantify within-assemblage diversities and abundance rankings for fossil encrusting species with different modes of growth. These data document macroevolutionary trends showing a transition from dominance of an apparently primitive mode of budding in the Early Cretaceous to derived modes through the Tertiary. The trends are characterized by their long duration and apparent convergence among systematic subgroups within the Cheilostomata. We then consider the validity of our observations as adaptive trends. Patterns of ecological dominance among living and fossil species indicate that different patterns of zooid formation are important determinants of success of colonies as reflected by their abundance, competitive ability, survivorship, and recovery from injury or predation. The consistency of the long-term trends and evidence for the existence of ecological mechanisms in fossil assemblages suggest a major evolutionary role for biotic interactions.

scholarly journals The hidden effect of inadvertent social information use on fluctuating predator–prey dynamics

2020 ◽  
Author(s):  
Zoltán Tóth
Keyword(s):  
Population Dynamics ◽  
Social Information ◽  
Biotic Interactions ◽  
Information Use ◽  
Population Level ◽  
High Amplitude ◽  
Sources Of Information ◽  
Predator Prey ◽  
Inadvertent Social Information ◽  
Social Information Use

AbstractUnderstanding biotic interactions and abiotic forces that govern population regulation is crucial for predicting stability from both theoretical and applied perspectives. In recent years, social information has been proposed to profoundly affect the dynamics of populations and facilitate the coexistence of interacting species. However, we have limited knowledge about how social information use influences cyclic and non-cyclic fluctuations of populations and if any population-level effects can be expected in species where individuals do not form social groups. In this study, I built individual-based models in a factorial design to investigate how predator avoidance behaviour and associated inadvertent social information (ISI) use alters the predictions of classical predator–prey population models in non-grouping (e.g., randomly moving) animals. Simulation results showed that ISI use in prey stabilized population dynamics by disrupting high-amplitude cyclic fluctuations in both predator and prey populations. Moreover, it also decreased the strength of the negative feedback of second-order dependence between predator and prey. I propose that if social cues are commonly used sources of information in animals regardless of the level of social organization, then similar social information-mediated effects on trophic interactions and population dynamics may be prevalent in natural communities.

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