scholarly journals Urbanization alters the abundance and composition of predator communities and leads to aphid outbreaks on urban trees

2020 ◽  
Author(s):  
Dávid Korányi ◽  
Viktor Szigeti ◽  
László Mezőfi ◽  
Előd Kondorosy ◽  
Viktor Markó
Keyword(s):  
Urban Environments ◽  
Urban Trees ◽  
Dispersal Ability ◽  
Abundance Pattern ◽  
Acer Campestre ◽  
Generalist Species ◽  
Predator Prey ◽  
Habitat Generalist ◽  
Filtering Effect ◽  
Predatory Arthropods

Abstract Urbanization can affect arthropod abundance in different ways. While species with narrow habitat range and low dispersal ability often respond negatively to urban environments, many habitat generalist species with good dispersal ability reach high densities in city centers. This filtering effect of urban habitats can strongly influence predator-prey-mutualist interactions and may therefore affect the abundance of predatory and phytophagous species both directly and indirectly. Here, we assessed the effect of urbanization on aphids, predatory arthropods, and ants on field maple (Acer campestre) trees in and around the city of Budapest, Hungary. We used the percentage of impervious surfaces within a 500 m radius of each site as an index of the degree of urbanization. We found that the abundance of aphids increased with increasing level of urbanization. However, abundance of predatory arthropods and occurrence of poorly dispersing species within the predator community were negatively related to urbanization, and we identified these two independent factors as significant predictors of aphid abundances. The abundance of ants decreased with urbanization, and contrary to our expectations, did not affect the abundance pattern of aphids. Our results suggest that urbanization, by altering the abundance and composition of predator communities, can disrupt biological control of aphid populations, and thus may contribute to the aphid outbreaks on urban trees.

scholarly journals Urban trees as social triggers: The case of the Ginkgo biloba specimen in Tallinn, Estonia

2019 ◽  
Vol 47 (1/2) ◽  
pp. 234-256 ◽  
Author(s):  
Riin Magnus ◽  
Heldur Sander
Keyword(s):  
Ginkgo Biloba ◽  
Cultural Memory ◽  
Well Being ◽  
Urban Environments ◽  
Urban Trees ◽  
Human Organism ◽  
Cultural Space ◽  
Cultural Ideal ◽  
Human Interactions ◽  
The Ideal

Urban trees are considered to be essential and integral to urban environments, to contribute to the biodiversity of cities as well as to the well-being of their inhabitants. In addition, urban trees may also serve as living memorials, helping to remember major social eruptions and to cement continuity with the past, but also as social disruptors that can induce clashes between different ideals of culture. In this paper, we focus on a specific case, a Ginkgo biloba specimen growing at Süda Street in the centre of Tallinn, in order to demonstrate how the shifts in the meaning attributed to a non-human organism can shape cultural memory and underlie social confrontations. Integrating an ecosemiotic approach to human-non-human interactions with Juri Lotman’s approach to cultural memory and cultural space, we point out how non-human organisms can delimit cultural space at different times and how the ideal of culture is shaped by different ways of incorporating or other species in the human cultural ideal or excluding them from it.

scholarly journals Insect herbivory on urban trees: Complementary effects of tree neighbours and predation

2020 ◽  
Author(s):  
Alex Stemmelen ◽  
Alain Paquette ◽  
Marie-Lise Benot ◽  
Yasmine Kadiri ◽  
Hervé Jactel ◽  
...  
Keyword(s):  
Insect Herbivory ◽  
Urban Ecosystems ◽  
Urban Environments ◽  
Tree Diversity ◽  
Urban Trees ◽  
List Type ◽  
Growth And Survival ◽  
Predator Attack ◽  
Peer Community ◽  
Survival Tree

AbstractInsect herbivory is an important component of forest ecosystems functioning and can affect tree growth and survival. Tree diversity is known to influence insect herbivory in natural forest, with most studies reporting a decrease in herbivory with increasing tree diversity. Urban ecosystems, on the other hand, differ in many ways from the forest ecosystem and the drivers of insect herbivory in cities are still debated.We monitored 48 urban trees from five species – three native and two exotic – in three parks of Montreal (Canada) for leaf insect herbivory and predator activity on artificial larvae, and linked herbivory with both predation and tree diversity in the vicinity of focal trees.Leaf insect herbivory decreased with increasing tree diversity and with increasing predator attack rate.Our findings indicate that tree diversity is a key determinant of multitrophic interactions between trees, herbivores and predators in urban environments and that managing tree diversity could contribute to pest control in cities.This article has been peer-reviewed and recommended by Peer Community in Ecologyhttps://doi.org/10.24072/pci.ecology.100061

Dictionary for Managing Trees in Urban Environments

2009 ◽  
Author(s):  
Danny B Draper ◽  
Peter A Richards
Keyword(s):  
Urban Forestry ◽  
Urban Environments ◽  
Urban Trees ◽  
Plain Language ◽  
Broad Application ◽  
Tree Management ◽  
Comprehensive List ◽  
Plant Sciences ◽  
Management Policies

Dictionary for Managing Trees in Urban Environments is a comprehensive list of terms used in the universal management of urban trees. Many of the terms are from arboricultural science, while others are derived from unproven but commonly applied concepts. Where the existing terminology to describe trees was limited or nonexistent, new terms have been introduced. This dictionary allows for broad application and use by a wide variety of people and conveys in plain language concepts that are sometimes complex. Most major terms have been cross referenced and diagrams have been added for greater understanding. While a number of pertinent botanical terms have been included, those readily found within dictionaries of general plant sciences and botany have been omitted. Dictionary for Managing Trees in Urban Environments promotes a greater understanding of arboriculture and urban forestry, and will assist in the preparation of reports for the management of trees, procedures and planning instruments, such as Tree Management Policies and Tree Management Orders.

Epiphyte Flora and Diversity on Basal Trunks of Six Old-Growth Forest Tree Species in Southern and Middle Boreal Finland

1996 ◽  
Vol 28 (5) ◽  
pp. 443-463 ◽  
Author(s):  
Mikko Kuusinen
Keyword(s):  
Tree Species ◽  
Boreal Forests ◽  
Forest Tree ◽  
Old Growth ◽  
Epiphytic Lichen ◽  
Generalist Species ◽  
Salix Caprea ◽  
Forest Tree Species ◽  
Old Growth Forest ◽  
Habitat Generalist

AbstractEpiphytic lichen and bryophyte species composition, richness and diversity were surveyed on basal trunks of six common old-growth forest tree species, Picea abies, Pinus sylvestris, Betula pendula, Alnus incana, Salix caprea and Populus tremula, in two old-growth forest areas, one in southern and one in middle boreal Finland. The average species numbers per tree ranged from 18 (Picea) to 27 (Salix) in the southern and from 20 (Populus) to 31 (Salix) in the middle boreal area. A few widespread habitat-generalist species, such as the foliose lichens Hypogymnia physodes and Platismatia glauca, were most abundant on all the tree species, except Populus. Most other epiphyte species showed at least a slight preference for one or two tree species. Populus proved to have the most distinct flora characterized by the abundance of certain, rather specialized crustose lichens and bryophytes. The number of species that occurred on only one tree species was highest on Populus (9) in the southern and on Alnus (18) in the middle boreal area. Differences in bark acidity and structure were the most likely explanations for the differences between tree species in the epiphytic flora and diversity. Salix and Populus were the most important of the tree species studied for the conservation of epiphyte diversity in the boreal forests of Finland.

scholarly journals Seasonal Variations of Pollinator Assemblages among Urban and Rural Habitats: A Comparative Approach Using a Standardized Plant Community

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 199
Author(s):  
Vincent Zaninotto ◽  
Adrien Perrard ◽  
Olivier Babiar ◽  
Amandine Hansart ◽  
Cécile Hignard ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Urban Environments ◽  
Green Spaces ◽  
Comparative Approach ◽  
Wild Bees ◽  
Generalist Species ◽  
Urban Green Spaces ◽  
Natural Grasslands ◽  
Insect Pollinators ◽  
The City

Even though urban green spaces may host a relatively high diversity of wild bees, urban environments impact the pollinator taxonomic and functional diversity in a way that is still misunderstood. Here, we provide an assessment of the taxonomic and functional composition of pollinator assemblages and their response to urbanization in the Paris region (France). We performed a spring-to-fall survey of insect pollinators in green spaces embedded in a dense urban matrix and in rural grasslands, using a plant setup standardized across sites and throughout the seasons. We compared pollinator species composition and the occurrence of bee functional traits over the two habitats. There was no difference in species richness between habitats, though urban assemblages were dominated by very abundant generalist species and displayed a lower evenness. They also included fewer brood parasitic, solitary or ground-nesting bees. Overall, bees tended to be larger in the city than in the semi-natural grasslands, and this trait exhibited seasonal variations. The urban environment filters out some life history traits of insect pollinators and alters their seasonal patterns, likely as a result of the fragmentation and scarcity of feeding and nesting resources. This could have repercussions on pollination networks and the efficiency of the pollination function.

Hunting for a Larger Diversity of Urban Trees in Western Europe—A Case Study from the Southern Caucasus

2019 ◽  
Vol 45 (5) ◽  
Author(s):  
Henrik Sjöman ◽  
Simon Hannus ◽  
Patrick Bellan ◽  
Tinatin Barblishvili ◽  
Tamaz Darchidze ◽  
...  
Keyword(s):  
Western Europe ◽  
Time Lag ◽  
Woody Species ◽  
Climate Scenario ◽  
Urban Environments ◽  
Urban Trees ◽  
Natural Habitats ◽  
Forest Reserves ◽  
In The Wild ◽  
Southern Caucasus

The primary aim of this study was to communicate a method for locating natural habitats where trees grows under conditions that are comparable to those in urban environments in terms of water stress. This is presented by analyzing five different forest reserves in the southern Caucasus (Republic of Georgia) where calculation of net water balance over the period of a year was conducted. This provided an insight into the drought at the sites during the growing season. The data were thereafter compared with similar calculations for five different cities in Western Europe in order to see if there were any matches in drought stress between the cities and the forest reserves. To extend the analysis, conditions in the five cities were assessed for high density and low density areas, and for the current climate and a future climate scenario. The comparisons revealed some matches between conditions in the forest reserves and those in different scenarios/areas in the cities. A secondary aim was to identify specific ecotypes in the wild demonstrating great potential to handle growing conditions similar to those in urban environments based on inventories of woody plants in the forest reserves. A total of 44 woody species were found in the forest reserve systems with a random distribution throughout the five study sites. Based on the commitments presented above a preliminary screening can be done where future tree selection focus can be directed towards highly promising species and ecotypes, which would undoubtedly limit the time lag before proper plant material can be released.

Co-occurrence patterns of rodents at multiple spatial scales: competitive release of generalists following habitat loss?

2019 ◽  
Vol 100 (4) ◽  
pp. 1229-1242 ◽  
Author(s):  
Thomas Püttker ◽  
Camila S Barros ◽  
Bruno T Pinotti ◽  
Adriana A Bueno ◽  
Renata Pardini
Keyword(s):  
Habitat Loss ◽  
Spatial Scales ◽  
Niche Partitioning ◽  
Large Data ◽  
Data Set ◽  
Generalist Species ◽  
Competitive Release ◽  
Spatial Niche ◽  
Habitat Generalist ◽  
Occurrence Patterns

AbstractTheory predicts that habitat generalist species are excluded by specialist species in optimal habitat for specialists, and empirical data commonly show a shift from specialist- to generalist-dominated communities following disturbance. We investigated co-occurrence patterns of habitat generalist and specialist terrestrial rodents at two spatial scales in the Atlantic Forest, aiming at evaluating the following hypotheses: 1) within-patch spatial niche partitioning promotes coexistence of generalists and specialists, leading to checkerboard presence-absence patterns at small (within-patch) rather than large (among-patch) scales; and 2) the decrease in abundance of specialists due to habitat loss promotes a competitive release of generalists, leading to negative covariance in abundance between generalists and specialists among patches. Drawing on a large data set including 363 sites within three patches in continuous forest, and 45 patches within three landscapes, we used C-scores based on presence-absence and abundance data to evaluate spatial segregation. We found consistent segregation between specialists and generalists at the within-patch rather than among-patch scale, but no consistent negative covariance in abundance between generalists and specialists among patches (as covarying species pairs varied across landscapes). Our findings suggest that spatial patterns caused by competition are scale-dependent, and coexistence of generalists and specialists is promoted by within-patch spatial niche partitioning. However, the influence of competitive release on the proliferation of generalists may be outweighed by other factors in fragmented landscapes.A teoria ecológica prevê que espécies generalistas de habitat são excluídas por espécies especialistas em hábitats ótimos para as especialistas, e dados empíricos comumente mostram uma mudança de dominância das comunidades - de especialistas para generalistas - após distúrbios. Nós investigamos os padrões de coocorrência de roedores terrestres generalistas e especialistas de habitat em duas escalas espaciais na Mata Atlântica, para testar as seguintes hipóteses: 1) a partição espacial do nicho dento de fragmentos promove a coexistência de generalistas e especialistas, levando a padrões de presença-ausência “tabuleiro de damas” em escalas pequenas (dentro de fragmento) mas não em escalas grandes (entre fragmentos); 2) a diminuição da abundância de especialistas devido à perda de habitat promove uma liberação competitiva de generalistas, levando a covariância negativa da abundância de generalistas e especialistas entre fragmentos. A partir de um grande banco de dados - 363 sítios dentro de três fragmentos de floresta contínua, e 45 fragmentos dentro de três paisagens, usamos C-scores baseados em dados de presença/ausência e abundância para avaliar a segregação espacial. Encontramos segregação consistente entre especialistas e generalistas na escala menor (dentro de fragmentos) e não na maior (entre fragmentos), mas não encontramos covariância negativa na abundância de generalistas e especialistas entre fragmentos (dado que os pares de espécies que covariaram mudou entre as paisagens). Nossos resultados sugerem que padrões espaciais causados por competição são dependentes de escala, e que a coexistência de generalistas e especialistas é promovida pela partição espacial de nicho dentro dos fragmentos. No entanto, a influência da liberação competitiva na proliferação de generalistas pode ser superada por outros fatores em paisagens fragmentadas.

scholarly journals Estimation of the Allergenic Potential of Urban Trees and Urban Parks: Towards the Healthy Design of Urban Green Spaces of the Future

2019 ◽  
Vol 16 (8) ◽  
pp. 1357 ◽  
Author(s):  
Cariñanos ◽  
Grilo ◽  
Pinho ◽  
Casares-Porcel ◽  
Branquinho ◽  
...  
Keyword(s):  
Urban Areas ◽  
Urban Environments ◽  
Urban Trees ◽  
Green Spaces ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Allergenic Potential ◽  
Causative Agents ◽  
The Impact ◽  
Ornamental Species

The impact of allergens emitted by urban green spaces on health is one of the main disservices of ecosystems. The objective of this work is to establish the potential allergenic value of some tree species in urban environments, so that the allergenicity of green spaces can be estimated through application of the Index of Urban Green Zones Allergenicity (IUGZA). Multiple types of green spaces in Mediterranean cities were selected for the estimation of IUGZ. The results show that some of the ornamental species native to the Mediterranean are among the main causative agents of allergy in the population; in particular, Oleaceae, Cupressaceae, Fagaceae, and Platanus hispanica. Variables of the strongest impact on IUGZA were the bioclimatic characteristics of the territory and design aspects, such as the density of trees and the number of species. We concluded that the methodology to assess the allergenicity associated with urban trees and urban areas presented in this work opens new perspectives in the design and planning of urban green spaces, pointing out the need to consider the potential allergenicity of a species when selecting plant material to be used in cities. Only then can urban green areas be inclusive spaces, in terms of public health.

Age-dependent colonization of urban habitats: a diachronic approach using carabid beetles and spiders

2013 ◽  
Vol 63 (3) ◽  
pp. 257-269 ◽  
Author(s):  
Marion Varet ◽  
Françoise Burel ◽  
Denis Lafage ◽  
Julien Pétillon
Keyword(s):  
Urban Areas ◽  
Time Lag ◽  
Ecosystem Dynamics ◽  
Carabid Beetles ◽  
Life History Trait ◽  
Generalist Species ◽  
High Dispersal ◽  
Specialist Species ◽  
Habitat Generalist ◽  
Habitat Specialist Species

Urbanization creates human disturbance that plays an important role in ecosystem dynamics. Most of the time, there is a time lag between disturbance and colonization. Opportunistic species with high dispersal power colonize first, while habitat specialist species with a lower power of dispersal colonize later; the communities change with time after disturbance. We hypothesize that, following the establishment of a new neighbourhood, arthropod communities will change from habitat generalists to specialists, and will be more similar to those of the adjacent countryside. We selected two groups of invertebrates often used as bioindicators, spiders and carabid beetles. The following parameters were estimated: assemblage composition, species richness, activity-density total and per life history trait (broad habitat preference). The field data were collected in 2010 within 3 towns located in France. Neighbourhoods of 10 and 30 years old were pair-matched in these towns and sampled using pitfall traps set randomly in hedgerows (120 traps in total). 2101 adult spiders belonging to 89 species were collected, whereas the 643 captured carabid beetles belonged to 24 species. We found no evidence of any significant change in carabid beetle and spider communities according to neighbourhood age. The assemblages were mainly composed of habitat generalist species. These results suggest that urban areas can be seen to be in continual state of disruption, and colonization of these areas is assumed to be relatively rapid (i.e., less than 10 years in our case study), although incomplete.

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