scholarly journals Urban habitat complexity affects species richness but not environmental filtering of morphologically-diverse ants

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1356 ◽  
Author(s):  
Alessandro Ossola ◽  
Michael A. Nash ◽  
Fiona J. Christie ◽  
Amy K. Hahs ◽  
Stephen J. Livesley
Keyword(s):  
Species Richness ◽  
Habitat Complexity ◽  
Morphological Traits ◽  
Environmental Filtering ◽  
Urban Ecosystems ◽  
Low Complexity ◽  
Urban Habitat ◽  
High Complexity ◽  
Natural Ecosystems ◽  
Ant Assemblages

Habitat complexity is a major determinant of structure and diversity of ant assemblages. Following the size-grain hypothesis, smaller ant species are likely to be advantaged in more complex habitats compared to larger species. Habitat complexity can act as an environmental filter based on species size and morphological traits, therefore affecting the overall structure and diversity of ant assemblages. In natural and semi-natural ecosystems, habitat complexity is principally regulated by ecological successions or disturbance such as fire and grazing. Urban ecosystems provide an opportunity to test relationships between habitat, ant assemblage structure and ant traits using novel combinations of habitat complexity generated and sustained by human management. We sampled ant assemblages in low-complexity and high-complexity parks, and high-complexity woodland remnants, hypothesizing that (i) ant abundance and species richness would be higher in high-complexity urban habitats, (ii) ant assemblages would differ between low- and high-complexity habitats and (iii) ants living in high-complexity habitats would be smaller than those living in low-complexity habitats. Contrary to our hypothesis, ant species richness was higher in low-complexity habitats compared to high-complexity habitats. Overall, ant assemblages were significantly different among the habitat complexity types investigated, although ant size and morphology remained the same. Habitat complexity appears to affect the structure of ant assemblages in urban ecosystems as previously observed in natural and semi-natural ecosystems. However, the habitat complexity filter does not seem to be linked to ant morphological traits related to body size.

Mechanisms underlying amphipod responses to zebra mussel (Dreissena polymorpha) invasion and implications for fish-amphipod interactions

1999 ◽  
Vol 56 (4) ◽  
pp. 679-685 ◽  
Author(s):  
María J González ◽  
Amy Downing
Keyword(s):  
Zebra Mussel ◽  
Dreissena Polymorpha ◽  
Habitat Complexity ◽  
Yellow Perch ◽  
Lepomis Macrochirus ◽  
Low Complexity ◽  
Substrate Preference ◽  
High Complexity ◽  
Bare Rock ◽  
Predator Species

We examined mechanisms underlying increased amphipod abundance after zebra mussels (Dreissena polymorpha) invaded Lake Erie. We conducted field substrate preference experiments to test the hypotheses that amphipods prefer (i) high-complexity substrates over low-complexity substrates and (or) (ii) substrates with high mussel feces and pseudofeces deposition over substrates with low deposition. We measured amphipod preference for bare rock, live mussels, and dead mussels in spring (May 1996) and summer (July and August 1995, June and August 1996). Habitat complexity affected amphipod habitat preference, and preference varied seasonally. In spring, amphipod density was highest on dead mussels, but the response was highly variable. In midsummer (June and July), amphipods showed no substrate preference. In late summer (August), amphipods consistently preferred high-complexity mussel substrates. Amphipods never preferred low-complexity substrates. We also evaluated effects of zebra mussel presence on fish-amphipod interactions in laboratory feeding trials. We tested the hypothesis that mussel presence decreases bluegill (Lepomis macrochirus) and yellow perch (Perca flavescens) predation on amphipods. Predation by bluegill but not yellow perch was significantly lowered by mussel presence. Our results support the hypothesis that the increase in amphipods upon zebra mussel invasion is due to increased habitat complexity, possibly by reducing predation risk. However, the effects of zebra mussel on fish-amphipod interactions depended on predator species.

scholarly journals Orchid bee fauna responds to habitat complexity on a savanna area (Cerrado) in Brazil.

Sociobiology ◽  
2016 ◽  
Vol 63 (2) ◽  
pp. 819 ◽  
Author(s):  
Yasmine Antonini ◽  
Rodrigo Assunção Silveira ◽  
Márcio Oliveira ◽  
Cristiane Martins ◽  
Reisla Oliveira
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Habitat Complexity ◽  
Habitat Structure ◽  
Dominant Species ◽  
Large Range ◽  
Physical Structure ◽  
High Complexity ◽  
Orchid Bee ◽  
Species Richness And Abundance

Habitat structure and complexity may broadly affect the diversity and composition of a variety of fauna in terrestrial systems. Here we investigated responses of orchid bee assemblages to habitat complexity, with the aim of assessing complexity as a useful surrogate for species diversity of this group. We test the following hypotheses: (i) There is a greater species richness and abundance of orchid bee in sites with high habitat complexity than lower habitat complexity; (ii) High habitat complexity sites have a different species composition of orchid bee than lower habitat complexity sites. For the purposes of our study, we defined habitat complexity as the heterogeneity in the arrangement in physical structure of habitat (vegetation), although there are a large range of operational definitions in the literature. As result, orchid bee species richness was higher in high complexity areas while community composition was not affected by habitat complexity, because Euglossa melanotricha and E. leucotricha were the dominant species, occurring in both environments. Habitat complexity, measured as a function of differences in multiple strata in forests, may be of great worth as a surrogate for the diversity of a range of arthropod groups including orchid bees. 

scholarly journals Effects of Urbanization on the Diversity, Abundance, and Composition of Ant Assemblages in an Arid City

2019 ◽  
Vol 48 (4) ◽  
pp. 836-846 ◽  
Author(s):  
Javier G Miguelena ◽  
Paul B Baker
Keyword(s):  
Species Richness ◽  
Arid Regions ◽  
Functional Group ◽  
Landscape Heterogeneity ◽  
Urban Ecosystems ◽  
Colony Growth ◽  
Limiting Factor ◽  
Habitat Types ◽  
Ant Assemblages ◽  
Ant Diversity

AbstractCities within arid regions make up a significant but understudied subset of the urban ecosystems of the world. To assess the effects of urbanization, fragmentation, and land-use change in an arid city, we sampled the ant assemblages in three habitat types in Tucson, Arizona: irrigated neighborhood parks, urban desert remnants, and preserved desert. We analyzed the abundance, species richness, evenness, as well as the species and functional group composition of ant assemblages. We found no significant differences in species richness or evenness. However, irrigated parks had significantly greater ant abundances. Although some exotic species were present in the urban habitats, they did not have significant effects on ant diversity. Ant assemblages from all three habitat types were distinct from each other in their composition. Irrigated parks included a significantly higher proportion of species typically found in cooler and wetter climates. The differences in abundance and species composition between irrigated parks and the other habitats are likely the effect of irrigation removing water as a limiting factor for colony growth and increasing resource availability, as well as producing a localized cooling effect. Our results show that arid urban ecosystems may include considerable biodiversity, in part thanks to increased landscape heterogeneity resulting from the irrigation of green areas.

Habitat Complexity Influences the Microhabitat Choices of Desert Beetles

2011 ◽  
Vol 57 (3) ◽  
pp. 213-221 ◽  
Author(s):  
Aaron Bartholomew ◽  
Karim Ebeid
Keyword(s):  
Habitat Complexity ◽  
Low Complexity ◽  
Common Species ◽  
Median Number ◽  
Natural Vegetation ◽  
Community Diversity ◽  
High Complexity ◽  
Microhabitat Preference ◽  
The Mean ◽  
Artificial Vegetation

We present a model for prey survivorship varying with average space size/prey width (Sp/Py) and total cover within an area (Ct/At), which are habitat complexity indices. The model predicts that prey survivorship is maximized at intermediate Sp/Py values, such that prey can fit through the spaces in a habitat, but their larger predators cannot. The model also predicts that prey survivorship increases with increasing cover (Ct/At), which interferes with predators' ability to detect prey. We deployed high-, medium-, and low-complexity artificial vegetation treatments with pit traps to determine if desert beetles respond to differences in habitat complexity consistent with our model's predictions for prey survivorship. We also deployed pit traps in natural vegetation and open sand to determine beetle microhabitat preference. The median number of both large and small beetles was higher in natural vegetation compared with open sand. The median number of large beetles was significantly higher in medium-complexity artificial treatments compared with both low- and high-complexity treatments.Prionotheca coronata, a common species of large beetle, was excluded from the high complexity treatments, as Sp/Py was <1 for them. This demonstrates that high-complexity habitats may exclude larger fauna, reducing community diversity. There was no difference in the mean number of small beetles captured in the different artificial complexity treatments. The results for large beetles are consistent with our model. Small beetles' distribution may be "predator-independent" since they did not respond to differences in complexity.

scholarly journals Distinguishing Planting Structures of Different Complexity from UAV Multispectral Images

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1994
Author(s):  
Qian Ma ◽  
Wenting Han ◽  
Shenjin Huang ◽  
Shide Dong ◽  
Guang Li ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Confusion Matrix ◽  
Object Oriented ◽  
Low Complexity ◽  
Classification Model ◽  
Recursive Feature Elimination ◽  
Support Vector ◽  
Multispectral Images ◽  
High Complexity ◽  
Structure Complexity

This study explores the classification potential of a multispectral classification model for farmland with planting structures of different complexity. Unmanned aerial vehicle (UAV) remote sensing technology is used to obtain multispectral images of three study areas with low-, medium-, and high-complexity planting structures, containing three, five, and eight types of crops, respectively. The feature subsets of three study areas are selected by recursive feature elimination (RFE). Object-oriented random forest (OB-RF) and object-oriented support vector machine (OB-SVM) classification models are established for the three study areas. After training the models with the feature subsets, the classification results are evaluated using a confusion matrix. The OB-RF and OB-SVM models’ classification accuracies are 97.09% and 99.13%, respectively, for the low-complexity planting structure. The equivalent values are 92.61% and 99.08% for the medium-complexity planting structure and 88.99% and 97.21% for the high-complexity planting structure. For farmland with fragmentary plots and a high-complexity planting structure, as the planting structure complexity changed from low to high, both models’ overall accuracy levels decreased. The overall accuracy of the OB-RF model decreased by 8.1%, and that of the OB-SVM model only decreased by 1.92%. OB-SVM achieves an overall classification accuracy of 97.21%, and a single-crop extraction accuracy of at least 85.65%. Therefore, UAV multispectral remote sensing can be used for classification applications in highly complex planting structures.

scholarly journals Biodiversity hanging by a thread: the importance of fungal litter-trapping systems in tropical rainforests

2011 ◽  
Vol 8 (3) ◽  
pp. 397-400 ◽  
Author(s):  
Jake L. Snaddon ◽  
Edgar C. Turner ◽  
Tom M. Fayle ◽  
Chey V. Khen ◽  
Paul Eggleton ◽  
...  
Keyword(s):  
Species Richness ◽  
Leaf Litter ◽  
Plant Diversity ◽  
Habitat Complexity ◽  
Tropical Rainforests ◽  
Dramatic Reduction ◽  
Experimental Removal ◽  
Crucial Component ◽  
High Species Richness ◽  
Vital Resource

The exceptionally high species richness of arthropods in tropical rainforests hinges on the complexity of the forest itself: that is, on features such as the high plant diversity, the layered nature of the canopy and the abundance and the diversity of epiphytes and litter. We here report on one important, but almost completely neglected, piece of this complex jigsaw—the intricate network of rhizomorph-forming fungi that ramify through the vegetation of the lower canopy and intercept falling leaf litter. We show that this litter-trapping network is abundant and intercepts substantial amounts of litter (257.3 kg ha −1 ): this exceeds the amount of material recorded in any other rainforest litter-trapping system. Experimental removal of this fungal network resulted in a dramatic reduction in both the abundance (decreased by 70.2 ± 4.1%) and morphospecies richness (decreased by 57.4 ± 5.1%) of arthropods. Since the lower canopy levels can contain the highest densities of arthropods, the proportion of the rainforest fauna dependent on the fungal networks is likely to be substantial. Fungal litter-trapping systems are therefore a crucial component of habitat complexity, providing a vital resource that contributes significantly to rainforest biodiversity.

scholarly journals Is polychaete diversity in the deep sublittoral of an Antarctic fiord related to habitat complexity?

2012 ◽  
Vol 33 (2) ◽  
pp. 181-197 ◽  
Author(s):  
Krzysztof Pabis ◽  
Jacek Siciński
Keyword(s):  
Species Richness ◽  
Habitat Complexity ◽  
Feeding Guilds ◽  
Depth Range ◽  
Soft Bottom ◽  
Admiralty Bay ◽  
Sea Floor ◽  
Species Richness And Diversity ◽  
South Shetlands ◽  
High Species Richness

Is polychaete diversity in the deep sublittoral of an Antarctic fiord related to habitat complexity?Seventy-six species of Polychaeta were found in 19 quantitative samples collected in the deep sublittoral (200-500 m) of Admiralty Bay (South Shetlands). Three assemblages were distinguished by similarity analysis (clustering, nMDS). The soft bottom in depths from 200 to 300m was strongly dominated byMaldane sarsi antarcticaand had very low species richness and diversity. The second assemblage was distinguished in the areas of the sea floor in the same depth range but with aggregations of Ascidiacea and Bryozoa. It was again characterized by high abundance ofMaldane sarsi antarctica, but showed significantly higher species richness and diversity. Diversity of polychaete feeding guilds was also high in these areas. This pattern was probably associated with an increased habitat complexity due to the presence of dense aggregations of large suspension feeders. High species richness and diversity was also noted in the third assemblage, associated with the deepest sublittoral (400-500 m) of Admiralty Bay. This is the area characterized by very stable environmental conditions, where the assemblage was dominated byTharyx cincinnatus, Sternaspissp.,Maldane sarsi antarctica, andAsychis amphiglypta.

Matching Forms as a Function of Complexity, Type of Match, and Retention Interval

1976 ◽  
Vol 43 (3_suppl) ◽  
pp. 1299-1302
Author(s):  
Virginia Brabender ◽  
Christopher Clay
Keyword(s):  
Retention Interval ◽  
Visual Processing ◽  
Present Experiment ◽  
Low Complexity ◽  
Stimulus Complexity ◽  
High Complexity

The present experiment tested the hypothesis that nominal processing increases as stimulus complexity increases. Subjects indicated whether two 4- or 12-sided forms, separated by an interval of .5 or 4.0 sec., were the same or different. “Same” responses corresponded to matches for physical or nominal identity. Longer RTs for high complexity than low complexity forms suggest that complexity affects the efficiency of visual processing rather than the occurrence of nominal processing. An interaction between type of match and interval, due to the longer RTs for matches of nominally identical forms at only the .5-sec. interval, indicates that at this interval, matches for physical and nominal identity are made with visual and nominal representations respectively.

scholarly journals The Necessary Triad: A Science-Education-Social Activity

2020 ◽  
Author(s):  
Aixa Hafsha
Keyword(s):  
Communication Network ◽  
Science Education ◽  
Natural Disasters ◽  
Everyday Life ◽  
Scientific Community ◽  
Social Activity ◽  
High Complexity ◽  
Natural Ecosystems ◽  
Grassroots Activism ◽  
The Earth

Recently the earth population and its natural ecosystems exist in very complex and permanently changing living conditions, being economy, social, natural or technological ones. More than that, it lives in the conditions of a high complexity, and such complexities may vary in its quality, time and space. Another feature of such life is its permanently growing speed of various transformations that is conditioned by many unseen and still unknown metabolic processes. The global communication network has made the emergency cases inseparable feature of everyday life. There are no ways out of it, and humanity has to predict the coming transformations and to adapt to them. The development of such interdisciplinary model is necessary if humanity wants to predict the coming transformations and to adapt to them. It has to be done by joint efforts of the scientists, scholars, teachers and the volunteers including the grassroots activism of concerned people. The triad of a scientific community, teachers and the teenagers is the necessary precondition for the developing necessary efforts in many directions: the revitalization of a futurology, in prediction and mitigation of the critical situations (accidents, natural disasters, and hybrid wars), and in the development of interdisciplinary researches. Gradually civilian volunteers are becoming more professional and mobile teams of civilian rescuers. Today, an individual safety has turned in a matter of each person, family or social group while the science-education-social activity triad has become a necessary precondition of survival.

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