Biotic Interactions in Lichen Community Development: A Review

1991 ◽  
Vol 23 (3) ◽  
pp. 205-214 ◽  
Author(s):  
James D. Lawrey
Keyword(s):  
Community Development ◽  
Competitive Exclusion ◽  
Biotic Interactions ◽  
Supporting Evidence ◽  
Biotic Factors ◽  
Higher Plant ◽  
Lichen Community ◽  
Ephemeral Species ◽  
Species Replacements

AbstractThe extent to which biotic factors (competition, predation/disease, longevity) regulate lichen community development can be addressed by considering a number of general trends expected in higher plant successions and searching for supporting evidence from lichen studies. Four of the most frequently observed (or predicted) trends during succession are that: (1) superior competitors replace poor competitors; (2) ecologically specialized species replace generalists; (3) chemically well-defended species replace poorly-defended species; (4) long-lived species replace ephemeral species. Available evidence suggests that, for many lichen communities, competitive exclusion rarely occurs once thalli are established. This is especially true for communities that develop on the most stable habitats. An absence of competitive exclusion suggests that lichen successions are driven more by additions of colonists than by species replacements, and replacement trends observed in higher plant successions are therefore observed less frequently inlichen successions.

An assessment of the role of biotic interactions and dynamic processes in the organization of species in a saxicolous lichen community

1989 ◽  
Vol 67 (7) ◽  
pp. 2025-2037 ◽  
Author(s):  
Elizabeth A. John
Keyword(s):  
Biotic Interactions ◽  
Dynamic Processes ◽  
Nearest Neighbour ◽  
Higher Plant ◽  
Association Analyses ◽  
Rock Face ◽  
Lichen Community ◽  
Diverse Community ◽  
Crustose Lichens

A saxicolous lichen community is examined for evidence of dynamic processes and biotic interactions among its members. Spatial relationships among species are examined in a series of association analyses at three scales: (i) the "nearest-neighbour" scale, i.e., associations between touching thalli; (ii) associations between thalli 10 and 20 cm apart; and (iii) associations at the scale of the whole rock face. The nearest-neighbour analysis reveals fundamental differences in the way crustose and foliose thalli sample their environment; crustose lichens are more likely to have uncolonized rock as a nearest neighbour, whereas foliose lichens are more likely to contact another thallus. Associations between species at the 10- and 20-cm scales are often negative, reflecting the degree of microhabitat specificity in this community; however, intraspecific associations at the same scale are often positive, possibly indicating local dispersal processes. At the whole-rock scale, there are many positive associations indicating that, even at this larger scale, microhabitat specificity is important. Thallus-size distributions are also studied, and these indicate that recruitment into lichen populations is an ongoing process, based on the assumption that small thalli are younger than large thalli. There is little evidence of succession to a higher plant community over most of the rocks at this 500-year-old site, and it is hypothesized that cyclic successional processes maintain this dynamic and diverse community.

scholarly journals Environmental factors influencing fine-scale distribution of Antarctica’s only endemic insect

Oecologia ◽  
2020 ◽  
Vol 194 (4) ◽  
pp. 529-539
Author(s):  
Leslie J. Potts ◽  
J. D. Gantz ◽  
Yuta Kawarasaki ◽  
Benjamin N. Philip ◽  
David J. Gonthier ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Spatial Scales ◽  
Abiotic Factors ◽  
Ecological Factors ◽  
Biotic Interactions ◽  
Species Distributions ◽  
Biotic Factors ◽  
Belgica Antarctica ◽  
Abiotic And Biotic Factors ◽  
The Antarctic

AbstractSpecies distributions are dependent on interactions with abiotic and biotic factors in the environment. Abiotic factors like temperature, moisture, and soil nutrients, along with biotic interactions within and between species, can all have strong influences on spatial distributions of plants and animals. Terrestrial Antarctic habitats are relatively simple and thus good systems to study ecological factors that drive species distributions and abundance. However, these environments are also sensitive to perturbation, and thus understanding the ecological drivers of species distribution is critical for predicting responses to environmental change. The Antarctic midge, Belgica antarctica, is the only endemic insect on the continent and has a patchy distribution along the Antarctic Peninsula. While its life history and physiology are well studied, factors that underlie variation in population density within its range are unknown. Previous work on Antarctic microfauna indicates that distribution over broad scales is primarily regulated by soil moisture, nitrogen content, and the presence of suitable plant life, but whether these patterns are true over smaller spatial scales has not been investigated. Here we sampled midges across five islands on the Antarctic Peninsula and tested a series of hypotheses to determine the relative influences of abiotic and biotic factors on midge abundance. While historical literature suggests that Antarctic organisms are limited by the abiotic environment, our best-supported hypothesis indicated that abundance is predicted by a combination of abiotic and biotic conditions. Our results are consistent with a growing body of literature that biotic interactions are more important in Antarctic ecosystems than historically appreciated.

An introduction to the 'micronet' of cyanobacterial harmful algal blooms (CyanoHABs): cyanobacteria, zooplankton and microorganisms: a review

2020 ◽  
Vol 71 (5) ◽  
pp. 636 ◽  
Author(s):  
Elżbieta Wilk-Woźniak
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Cyanobacterial Blooms ◽  
Biotic Factors ◽  
New Findings ◽  
Change Temperature ◽  
Abiotic And Biotic Factors ◽  
Cyanobacterial Harmful Algal Blooms

Cyanobacterial harmful algal blooms are known all around the world. Climate change (temperature increase) and human activity (eutrophication) are factors that promote the proliferation of cyanobacteria, leading to the development of blooms and the release of toxins. Abiotic and biotic factors are responsible for the development of blooms and how long they last. Although the abiotic factors controlling blooms are well known, knowledge of biotic factors and their interactions is still lacking. This paper reviews five levels of biotic interactions, namely cyanobacteria–zooplankton, cyanobacteria–ciliates, cyanobacteria–bacteria, cyanobacteria–viruses and cyanobacteria–fungi, showing a more complex food web network than was previously thought. New findings published recently, such as the relationships between cyanobacteria and viruses or cyanobacteria and fungi, indicate that cyanobacterial blooms are not the end of the cycle of events taking place in water habitats, but rather the middle of them. As such, a new approach needs to consider mutual connections, genetic response, horizontal gene transfer and non-linear flow of carbon.

scholarly journals Spatial scale modulates the strength of ecological processes driving disease distributions

2016 ◽  
Vol 113 (24) ◽  
pp. E3359-E3364 ◽  
Author(s):  
Jeremy M. Cohen ◽  
David J. Civitello ◽  
Amber J. Brace ◽  
Erin M. Feichtinger ◽  
C. Nicole Ortega ◽  
...  
Keyword(s):  
Population Density ◽  
Human Population ◽  
Large Scale ◽  
Climatic Factors ◽  
Biotic Interactions ◽  
Amphibian Declines ◽  
Biotic Factors ◽  
Human Population Density ◽  
Single Scale ◽  
Anthropogenic Modifications

Humans are altering the distribution of species by changing the climate and disrupting biotic interactions and dispersal. A fundamental hypothesis in spatial ecology suggests that these effects are scale dependent; biotic interactions should shape distributions at local scales, whereas climate should dominate at regional scales. If so, common single-scale analyses might misestimate the impacts of anthropogenic modifications on biodiversity and the environment. However, large-scale datasets necessary to test these hypotheses have not been available until recently. Here we conduct a cross-continental, cross-scale (almost five orders of magnitude) analysis of the influence of biotic and abiotic processes and human population density on the distribution of three emerging pathogens: the amphibian chytrid fungus implicated in worldwide amphibian declines and West Nile virus and the bacterium that causes Lyme disease (Borrelia burgdorferi), which are responsible for ongoing human health crises. In all three systems, we show that biotic factors were significant predictors of pathogen distributions in multiple regression models only at local scales (∼102–103 km2), whereas climate and human population density always were significant only at relatively larger, regional scales (usually >104 km2). Spatial autocorrelation analyses revealed that biotic factors were more variable at smaller scales, whereas climatic factors were more variable at larger scales, as is consistent with the prediction that factors should be important at the scales at which they vary the most. Finally, no single scale could detect the importance of all three categories of processes. These results highlight that common single-scale analyses can misrepresent the true impact of anthropogenic modifications on biodiversity and the environment.

Influence of abiotic and biotic factors on two co-occurring species of Bolboschoenus

2000 ◽  
Vol 51 (1) ◽  
pp. 73 ◽  
Author(s):  
Mark A. Siebentritt ◽  
George G. Ganf
Keyword(s):  
Water Depth ◽  
Abiotic Factors ◽  
Elevation Gradient ◽  
Biotic Interactions ◽  
Biotic Factors ◽  
Depth Gradient ◽  
Shoot Height ◽  
Relative Growth ◽  
Net Assimilation ◽  
Abiotic And Biotic Factors

Distribution of the emergent macrophytes Bolboschoenus medianus and Bolboschoenus caldwellii is dominated by the latter at regions higher on the elevation gradient, whereas the former is dominant further down the gradient. Monocultures and mixtures of plants were grown across a water-depth gradient in experimental ponds to determine whether distribution is due to abiotic factors, biotic factors, or a combination of both. Monocultures of each species tolerated exposure, showing little variation in relative growth rate (RGR), net assimilation rate (NAR) or leaf area ratio (LAR). Survival when initially flooded was dependent on shoot height. Plants surviving inundation responded by increasing height through reallocation of biomass. The RGR of B. medianus was maintained across the water-depth gradient by increasing NAR as LAR declined. The RGR of B. caldwellii beyond a depth of −20 cm declined because reductions in LAR were not paralleled by increases in NAR. Mixtures of species growing at 20 cm and 0 cm indicated that biotic interactions occurred and that B. caldwellii was the dominant species. Neither species dominated at −60 cm, presumably because this was beyond the depth tolerated by both species. The study suggests that the zonation of B. medianus and B. caldwellii is attributable to a combination of both abiotic and biotic factors.

Spatial variation in the effects of predator exclusion on epifaunal community development in seagrass beds

2020 ◽  
Vol 649 ◽  
pp. 21-33 ◽  
Author(s):  
DS Janiak ◽  
CJ Freeman ◽  
J Seemann ◽  
JE Campbell ◽  
VJ Paul ◽  
...  
Keyword(s):  
Community Development ◽  
Biotic Resistance ◽  
Experimental Studies ◽  
Biotic Interactions ◽  
Habitat Modification ◽  
Taxonomic Resolution ◽  
Ecological Communities ◽  
Predator Exclusion ◽  
Epifaunal Communities ◽  
The Impact

Biotic interactions have critical effects on the structure of ecological communities, and the variation in the strength of these interactions over space and time contributes to biogeographic variation in communities. Predation shapes community composition in a variety of habitats, although there have been comparatively few experimental studies of these effects across latitudinal scales. We tested the impact of predator exclusion on the development of epifaunal communities across 3 sites (Florida [USA], Belize, and Panama) in seagrass habitats dominated by Thalassia testudinum using caged and uncaged settlement panels. We found that predators altered composition and slowed development of epifaunal communities. The nature and magnitude of these effects, however, were complex, site-dependent, and tightly coupled to community development. Fast-growing, soft-bodied species dominated space when predators were excluded, while more resistant calcifying species were dominant in communities exposed to predators. In Panama, non-native ascidians dominated communities in cages, while ascidians were consumed when exposed to predators, indicating the importance of biotic resistance at that site. Predators also reduced the abundance of associated small mobile fauna, and the positive correlation between mobile faunal abundances and sessile biomass in our study suggests a potential indirect effect of predator-mediated habitat modification. Overall, prey characteristics were important in explaining the site-specific effects of predators on communities, indicating that taxonomic resolution can influence the results of multi-regional studies examining the mechanisms affecting community structure.

scholarly journals Commensal associations and benthic habitats shape macroevolution of the bivalve clade Galeommatoidea

2016 ◽  
Vol 283 (1834) ◽  
pp. 20161006 ◽  
Author(s):  
Jingchun Li ◽  
Diarmaid Ó Foighil ◽  
Ellen E. Strong
Keyword(s):  
Niche Partitioning ◽  
Ecological Factors ◽  
Biotic Interactions ◽  
Marine Biodiversity ◽  
Biotic Factors ◽  
Free Living ◽  
Symbiotic Associations ◽  
Large Numbers ◽  
Living Species ◽  
Abiotic And Biotic Factors

The great diversity of marine life has been shaped by the interplay between abiotic and biotic factors. Among different biotic interactions, symbiosis is an important yet less studied phenomenon. Here, we tested how symbiotic associations affected marine diversification, using the bivalve superfamily Galeommatoidea as a study system. This superfamily contains large numbers of obligate commensal as well as free-living species and is therefore amenable to comparative approaches. We constructed a global molecular phylogeny of Galeommatoidea and compared macroevolutionary patterns between free-living and commensal lineages. Our analyses inferred that commensalism/sediment-dwelling is likely to be the ancestral condition of Galeommatoidea and that secondary invasions of hard-bottom habitats linked to the loss of commensalism. One major clade containing most of the free-living species exhibits a 2–4 times higher diversification rate than that of the commensals, likely driven by frequent niche partitioning in highly heterogeneous hard-bottom habitats. However, commensal clades show much higher within-clade morphological disparity, likely promoted by their intimate associations with diverse hosts. Our study highlights the importance of interactions between different ecological factors in shaping marine macroevolution and that biotic factors cannot be ignored if we wish to fully understand processes that generate marine biodiversity.

scholarly journals Reorganization of surviving mammal communities after the end-Pleistocene megafaunal extinction

Science ◽  
2019 ◽  
Vol 365 (6459) ◽  
pp. 1305-1308 ◽  
Author(s):  
Anikó B. Tóth ◽  
S. Kathleen Lyons ◽  
W. Andrew Barr ◽  
Anna K. Behrensmeyer ◽  
Jessica L. Blois ◽  
...  
Keyword(s):  
Community Assembly ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Niche Overlap ◽  
Biotic Factors ◽  
Large Mammals ◽  
Continental Scale ◽  
Species Pairs ◽  
Mammal Communities ◽  
Over Time

Large mammals are at high risk of extinction globally. To understand the consequences of their demise for community assembly, we tracked community structure through the end-Pleistocene megafaunal extinction in North America. We decomposed the effects of biotic and abiotic factors by analyzing co-occurrence within the mutual ranges of species pairs. Although shifting climate drove an increase in niche overlap, co-occurrence decreased, signaling shifts in biotic interactions. Furthermore, the effect of abiotic factors on co-occurrence remained constant over time while the effect of biotic factors decreased. Biotic factors apparently played a key role in continental-scale community assembly before the extinctions. Specifically, large mammals likely promoted co-occurrence in the Pleistocene, and their loss contributed to the modern assembly pattern in which co-occurrence frequently falls below random expectations.

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