scholarly journals Herbivory on the pedunculate oak along urbanization range in Europe: effects of local forest cover and insect feeding guild

2021 ◽  
Author(s):  
Elena Valdés-Correcher ◽  
Anna Popova ◽  
Andrea Galmán ◽  
Andreas Prinzing ◽  
Andrey Selikhovkin ◽  
...  
Keyword(s):  
Forest Cover ◽  
Interactive Effect ◽  
Insect Herbivory ◽  
Canopy Cover ◽  
Biotic Interactions ◽  
Insect Herbivores ◽  
Pedunculate Oak ◽  
Feeding Guild ◽  
Leaf Miners ◽  
Negative Effect

Urbanization is recognized as an important driver of the diversity and abundance of tree associated insect herbivores, but its consequences for insect herbivory are controversial. A likely source of variability among studies is the insufficient consideration of intra-urban variability in forest cover. With the help of citizen scientists, we investigated the independent and interactive effect of urbanization and local canopy cover on insect herbivory in the pedunculate oak (Quercus robur) throughout most of its geographic range in Europe. The damage caused by chewing insect herbivores as well as the incidence of leaf-mining and gall-inducing herbivores consistently decreased with increasing urbanization around focal oaks. Herbivory by chewing herbivores increased with increasing forest cover, regardless of urbanization. In contrast, an increase in local canopy cover buffered the negative effect of urbanization on leaf-miners and strengthened its effect on gall-inducers. These results show the complexity of plant-herbivore interactions in urbanized areas, highlighting that the presence of local canopy cover within cities has the potential to attenuate or modify the effect of urbanization on biotic interactions.

scholarly journals Insect herbivory and avian insectivory in novel native oak forests: divergent effects of stand size and connectivity

2019 ◽  
Author(s):  
Elena Valdés-Correcher ◽  
Inge van Halder ◽  
Luc Barbaro ◽  
Bastien Castagneyrol ◽  
Arndt Hampe
Keyword(s):  
Insect Herbivory ◽  
Oak Forests ◽  
Suitable Habitat ◽  
Native Forest ◽  
Minor Effect ◽  
Insect Herbivores ◽  
Pedunculate Oak ◽  
Forest Stands ◽  
Leaf Miners ◽  
Rural Landscapes

AbstractThe value of novel native broadleaf woodlands for biodiversity conservation is important to consider for adequate forest management in rural landscapes. Passive reforestation has been proposed as a cost-efficient tool for creating networks of novel native forest stands that would help restoring biodiversity and associated ecosystem services. Yet to date the ecological functioning of such stands remains strongly understudied compared to forest remnants resulting from longer-term fragmentation. We assessed how the size and connectivity of newly established Pedunculate oak (Quercus robur L.) stands in rural landscapes of SW France affect rates of herbivory by different insect guilds as well as rates of avian insectivory and the abundance and richness of insectivorous birds. Comparing 18 novel forest stands along a gradient of size (0.04-1.15 ha) and cover of broadleaf forests in the surroundings (0-30% within a 500 radius), we found that even the smallest stands are colonised by leaf miners and chewers/skeletonizers, and that rates of herbivory are globally comparable to those reported from older and larger oak forests. The size of stands had a relatively minor effect on herbivory, whereas it increased the abundance of insectivorous bird. It also determined rates of avian insectivory as estimated by an experiment with plasticine caterpillars. These rates were however rather low and unrelated with the extent of herbivory in the stand. Overall, our study indicates that insect herbivores tend to react more rapidly to the establishment of novel native forests than their avian predators as the latter may depend on the development of larger patches of suitable habitat in the surrounding landscape. To favour a rapid build-up of diverse, and hence stable, trophic networks involving insect herbivores and their predators, woodland creation schemes should therefore primarily focus on habitat size and quality.

scholarly journals Plasticity in Induced Resistance to Sequential Attack by Multiple Herbivores in Brassica Nigra

2021 ◽  
Author(s):  
Maite Fernández de Bobadilla ◽  
Roel Van Wiechen ◽  
Gerrit Gort ◽  
Erik H. Poelman
Keyword(s):  
Induced Resistance ◽  
Plant Resistance ◽  
Brassica Nigra ◽  
Plant Responses ◽  
Insect Herbivores ◽  
Plant Fitness ◽  
Feeding Guild ◽  
Induced Plant Responses ◽  
Negative Effect ◽  
History Of

Abstract In nature, plants interact with multiple insect herbivores that may arrive simultaneously or sequentially. Because insect herbivores often have a negative effect on plant fitness, plants have evolved mechanisms to defend their tissues from being eaten. There is extensive knowledge on the regulation of induced plant responses to single or dual attack. However, we lack information on how plants defend against the attack of multiple herbivores that arrive sequentially. In this study, we investigated whether Brassica nigra plants are able to defend themselves against caterpillars of the late arriving herbivore Plutella xylostella, when plants had been previously exposed to sequential attack by four other herbivores. We manipulated the order of arrival and the history of attack by four herbivores to investigate which patterns in sequential herbivory determine resistance against the fifth attacker. We recorded that history of sequential herbivore attack differentially affected the capability of Brassica nigra plants to defend themselves against larvae of P. xylostella. A sequence of attack with four episodes of attack by P. xylostella induced resistance to larvae of P. xylostella. The number of times the plant was attacked by herbivores of the same feeding guild, the identity of the first attacker, the identity and the guild of the last attacker as well as the order of attackers within the sequence of multiple herbivores influenced plant resistance to subsequent herbivory. In conclusion, this study shows that history of sequential attack is an important factor determining plant resistance to herbivores.

scholarly journals The Effectiveness of China’s National Forest Protection Program and National-level Nature Reserves, 2000 to 2010

2013 ◽  
Author(s):  
Guopeng Ren ◽  
Stephen S. Young ◽  
Lin Wang ◽  
Wei Wang ◽  
Yongcheng Long ◽  
...  
Keyword(s):  
Forest Cover ◽  
National Level ◽  
Mainland China ◽  
Canopy Cover ◽  
Nature Reserves ◽  
National Forest ◽  
Natural Forests ◽  
Forest Protection ◽  
Deforestation Rate ◽  
Deforestation Rates

There is profound interest in knowing the degree to which China’s institutions are capable of protecting its natural forests and biodiversity in the face of economic and political change. China’s two most important forest protection policies are its National Forest Protection Program (NFPP) and its National-level Nature Reserves (NNRs). The NFPP was implemented in 17 provinces starting in the year 2000 in response to deforestation-caused flooding. We used MODIS data (MOD13Q1) to estimate forest cover and forest loss across mainland China, and we report that 1.765 million km2or 18.7% of mainland China was covered in forest (12.3%, canopy cover > 70%) and woodland (6.4%, 40% ≤ canopy cover < 70%) in 2000. By 2010, a total of 480,203 km2of forest+woodland was lost, amounting to an annual deforestation rate of 2.7%. The forest-only loss was 127,473 km2, or 1.05% annually. The three most rapidly deforested provinces were outside NFPP jurisdiction, in the southeast. Within the NFPP provinces, the annual forest+woodland loss rate was 2.26%, and the forest-only rate was 0.62%. Because these loss rates are likely overestimates, China appears to have achieved, and even exceeded, its NFPP target of reducing deforestation to 1.1% annually in the target provinces. We also assemble the first-ever polygon dataset for China’s forested NNRs (n=237), which covered 74,030 km2in 2000. Conventional unmatched and covariate-matching analyses both find that about two-thirds of China’s NNRs exhibit effectiveness in protecting forest cover and that within-NNR deforestation rates are higher in provinces that have higher overall deforestation.

scholarly journals The relationship between resource abundance and insect herbivory on islands

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256183
Author(s):  
Bora Shin ◽  
Jae-Young Lee ◽  
Nang-Hee Kim ◽  
Sei-Woong Choi
Keyword(s):  
Plant Species ◽  
Forest Cover ◽  
Food Resource ◽  
Phytophagous Insects ◽  
Feeding Guild ◽  
Resource Abundance ◽  
Variable Effect ◽  
The Relationship ◽  
External Feeding ◽  
Number Of Plant Species

We examined the relationship between resource abundance and the feeding activity of phytophagous insects on three common island plants. The aim was to investigate the correlation between phytophagous insects’ abundance and availability of food and island geography. We collected 30,835 leaves from three tree species groups (Mallotus japonicus, Prunus species, and Quercus species) on 18 islands in southwest Korea. The number of plant resources for herbivores varied: the number of leaves per shoot was the highest in Mallotus, leaf weight and the water content per leaf was significantly lower in Quercus species. External feeding was higher for Prunus and Quercus species, whereas the internal feeding type was significantly higher for Quercus species. Geography (area and distance), elevation and food resource (elevation, number of plant species, and the forest cover rate) had a variable effect on phytophagous insects feeding activities: distance and the number of plant species were more explainable to the external feeding guild. In contrast, area and forest cover were more to the internal feeding guild.

Degradation or recovery of argan woodlands in South Morocco? Tree count from satellite imagery between 1967–2019 may underestimate pressures on dryland forests status

2021 ◽  
Author(s):  
Irene Marzolff ◽  
Mario Kirchhoff ◽  
Robin Stephan ◽  
Manuel Seeger ◽  
Ali Aït Hssaïne ◽  
...  
Keyword(s):  
Forest Cover ◽  
Canopy Cover ◽  
Biosphere Reserve ◽  
Agroforestry System ◽  
Tree Density ◽  
Tree Cover ◽  
Positive Development ◽  
Natural State ◽  
Remotely Sensed Data ◽  
Change Analysis

&lt;p&gt;In semi-arid to arid South-west Morocco, the once ubiquitous endemic argan tree (&lt;em&gt;Argania spinosa&lt;/em&gt;) forms the basis of a traditional silvo-pastoral agroforestry system with complex usage rights involving pasturing and tree-browsing by goats, sheep and camels, smallholder agriculture and oil production. Widespread clearing of the open-canopy argan forests has been undertaken in the 12&lt;sup&gt;th&lt;/sup&gt;&amp;#8211;17&lt;sup&gt;th&lt;/sup&gt; century for sugarcane production, and again in the 20&lt;sup&gt;th&lt;/sup&gt; century for fuelwood extraction and conversion to commercial agriculture. The remaining argan woodlands have continued to decline due to firewood extraction, charcoal-making, overgrazing and overbrowsing. Soil and vegetation are increasingly being degraded; natural rejuvenation is hindered, and soil-erosion rates rise due to reduced infiltration and increased runoff. Numerous studies indicate that tree density and canopy cover have been generally decreasing for the last 200 years. However, there is little quantitative and spatially explicit information about these forest-cover dynamics.&lt;/p&gt;&lt;p&gt;In our study, the tree-cover change between 1967 and 2019 was analysed for 30 test sites of 1 ha each in argan woodlands of different degradation stages in the provinces of Taroudant, Agadir Ida-Outanane and Chtouka-A&amp;#239;t Baha. We used historical black-and-white satellite photography from the American reconnaissance programme CORONA, recent high-resolution multispectral imagery from the commercial WorldView satellites and ultrahigh resolution small-format aerial photography taken with an unmanned aerial system (UAS) to map the presence, absence and comparative crown-size class of 2610 trees in 1967 and 2019. We supplemented the remotely-sensed data with field observations on tree structure and architecture.&lt;/p&gt;&lt;p&gt;Results show that plant densities reach up to 300 argan trees and shrubs per hectare, and the mean tree density has increased from 58 trees/ha in 1967 to 86 trees/ha in 2019. While 7% of the 1967 trees have vanished today, more than one third of today&amp;#8217;s trees could not be observed in 1967. This positive change has a high uncertainty, however, as most of the increase concerns small trees (&lt; 3 m diameter) which might have been missed on the lower-resolution CORONA images.&lt;/p&gt;&lt;p&gt;When combined with our field data on tree architecture, tree count &amp;#8211; albeit a parameter easily attained by remote sensing &amp;#8211; is revealed as too simple an indicator for argan-forest dynamics, and the first impression of a positive development needs to be revised: The new small trees as well as trees with decreased crown sizes clearly show much stronger degradation characteristics than others, indicating increased pressures on the argan ecosystem during recent decades. Structural traits of the smaller trees also suggest that the apparent increase of tree count is not a result of natural rejuvenation, but mostly of stump re-sprouting, often into multi-stemmed trees, after felling of a tree. The density of the argan forest in the 1960s, prior to the general availability of cooking gas in the region and before the stronger enforcement of the argan logging ban following the declaration of the UNESCO biosphere reserve, may have marked a historic low in our study area, making the baseline of our change analysis far removed from the potential natural state of the argan ecosystem.&lt;/p&gt;

Economic Decline, Social Identity, and Authoritarian Values in the United States

2021 ◽  
Author(s):  
Cameron Ballard-Rosa ◽  
Amalie Jensen ◽  
Kenneth Scheve
Keyword(s):  
United States ◽  
Social Identity ◽  
Social Norm ◽  
Interactive Effect ◽  
The United States ◽  
Vote Choice ◽  
Economic Decline ◽  
Induced Labor ◽  
The Social ◽  
Negative Effect

Abstract Why does the contemporary backlash against globalization in the United States have such a substantial authoritarian character? We argue that sustained economic decline has a negative effect on the social identity of historically dominant groups. These losses lead individuals to be more likely to want to enforce social norm conformity—that is, adopt more authoritarian values—as a way to preserve social status and this effect is greater the larger the size of other groups in the population. Central to our account is the expectation of an interactive effect of local economic and demographic conditions in forging value responses to economic decline. The article evaluates this argument using an original 2017 representative survey in the United States. We find that individuals living in relatively diverse regions facing more intense competition from Chinese imports have more authoritarian values. We further find that the greater effect of globalization-induced labor market decline in more diverse areas is also evident for vote choice in the 2016 Presidential election.

scholarly journals Effects of Corporate Social Responsibility on Firm Performance: Does Customer Satisfaction Matter?

2020 ◽  
Vol 12 (18) ◽  
pp. 7545 ◽  
Author(s):  
An-Pin Wei ◽  
Chi-Lu Peng ◽  
Hao-Chen Huang ◽  
Shang-Pao Yeh
Keyword(s):  
Corporate Social Responsibility ◽  
Firm Performance ◽  
Customer Satisfaction ◽  
Social Responsibility ◽  
Financial Performance ◽  
Interactive Effect ◽  
The United States ◽  
Negative Effect ◽  
Corporate Social Irresponsibility ◽  
Corporate Social

Academic research has shed light on the empirical relationships among a firm’s corporate social responsibility (CSR), corporate social irresponsibility (CSiR) and firm performance and on the firm’s customer satisfaction–firm performance relationship in different markets. However, little notice has been taken of whether the coexistence of corporate social responsibility, corporate social irresponsibility and customer satisfaction has an interactive effect on firm performance. This study aims to examine the effects of their interaction on firm performance from an investment perspective. Using unbalanced panel regression to test a sample of publicly traded firms from the United States, this study finds that, in general, firms with higher customer satisfaction earn positive changes in abnormal stock returns. For firms that engage in CSR, CSR positively affects corporate performance, whereas firms’ social irresponsibility activities reduce firms’ financial performance. All else equal, a positive interactive effect of CSiR and customer satisfaction on stock return was observed. The results reveal that high customer satisfaction can alleviate the negative effect of corporate social irresponsibility on firms’ financial performance. Our findings will help management executives and investors to understand that the negative effect of a firm’s unforeseen events on firm performance can be weakened by increasing customer satisfaction.

scholarly journals Leaf chemical defences and insect herbivory in oak: accounting for canopy position unravels marked genetic relatedness effects

2020 ◽  
Vol 126 (5) ◽  
pp. 865-872 ◽  
Author(s):  
Elena Valdés-Correcher ◽  
Audrey Bourdin ◽  
Santiago C González-Martínez ◽  
Xoaquín Moreira ◽  
Andrea Galmán ◽  
...  
Keyword(s):  
Genetic Relatedness ◽  
Insect Herbivory ◽  
Tree Canopy ◽  
Pedunculate Oak ◽  
Oak Woodlands ◽  
Chemical Defences ◽  
Canopy Effect ◽  
Canopy Position ◽  
Variation Explained ◽  
Genetic Signal

Abstract Background and Aims Highly controlled experiments document that plant genetic diversity and relatedness can shape herbivore communities and patterns of herbivory. Evidence from the field is, however, scarce and inconsistent. We assessed whether a genetic signal underlying herbivory can be detected in oak woodlands when accounting for variation at smaller (within-tree) and larger (among-stand) scales. Methods We tested relationships between tree genetic relatedness, leaf chemical defences and insect herbivory for different canopy layers in 240 trees from 15 pedunculate oak (Quercus robur) forest stands. We partitioned sources of variability in herbivory and defences among stands, individuals and branches. Key Results Leaf defences, insect herbivory and their relationship differed systematically between the upper and the lower tree canopy. When accounting for this canopy effect, the variation explained by tree genetic relatedness rose from 2.8 to 34.1 % for herbivory and from 7.1 to 13.8 % for leaf defences. The effect was driven by markedly stronger relationships in the upper canopy. Conclusions Our findings illustrate that considerable effects of the host plant genotype on levels of leaf chemical defences and associated insect herbivory can be detected in natural tree populations when within-individual variation is properly accounted for.

scholarly journals The biology of the limnephilid caddisfly Dicosmoecus gilvipes (Hagen) in Northern California and Oregon (USA) Streams

Zoosymposia ◽  
2011 ◽  
Vol 5 (1) ◽  
pp. 413-419 ◽  
Author(s):  
Vincent H. Resh ◽  
Morgan Hannaford ◽  
John K. Jackson ◽  
Gary A. Lamberti ◽  
Patina K. Mendez
Keyword(s):  
Aquatic Insects ◽  
Sex Pheromones ◽  
Model Organism ◽  
Biotic Interactions ◽  
Northern California ◽  
Large Size ◽  
Behavioral Studies ◽  
Negative Effect ◽  
Males And Females ◽  
Dicosmoecus Gilvipes

The limnephilid caddisfly Dicosmoecus gilvipies (Hagen) occurs in many streams of northwestern United States and British Columbia.  Because of the large size of the fully grown larva, its synchronous emergence pattern, and its frequent imitation by fly-fishing anglers, D. gilvipes is one of the best known North American aquatic insects. Egg masses are found at the bases of Carex sedges. Cases of early larval instars are made of organic material and detritus; 3rd and 4th instars incorporate pebbles into cases. The 5th-instar case is made entirely of mineral material. Larvae can travel up to 25 m per day, and are predominantly scraper-grazers. Fifth instars attach their cases to the underside of boulders in mid-summer and remain dormant until pupation in autumn.  All northern California populations known are univoltine. Adult females use sex pheromones to attract males; most males come to trapped females in the 1st hour after sunset.  In laboratory studies, males and females fly during the mate attraction period but generally not at other times.  Males but not females exhibit circadian rhythms that govern flight periodicity. In enclosures to study biotic interactions, the density of D. gilvipes larvae has a negative effect on the densities of sessile grazers. This species has been widely used in trophic and behavioral studies conducted in the laboratory and field, and may be a model organism for ecological studies of caddisflies and other benthic macroinvertebrates.

scholarly journals Host specificity of insect herbivores in tropical forests

2005 ◽  
Vol 272 (1568) ◽  
pp. 1083-1090 ◽  
Author(s):  
Vojtech Novotny ◽  
Yves Basset
Keyword(s):  
Host Specificity ◽  
Tropical Forests ◽  
Plant Species ◽  
Field Studies ◽  
Tropical Species ◽  
Distribution Data ◽  
Insect Herbivores ◽  
Leaf Miners ◽  
Experimental Conditions ◽  
Plant Phylogeny

Studies of host specificity in tropical insect herbivores are evolving from a focus on insect distribution data obtained by canopy fogging and other mass collecting methods, to a focus on obtaining data on insect rearing and experimentally verified feeding patterns. We review this transition and identify persisting methodological problems. Replicated quantitative surveys of plant–herbivore food webs, based on sampling efforts of an order of magnitude greater than is customary at present, may be cost-effectively achieved by small research teams supported by local assistants. Survey designs that separate historical and ecological determinants of host specificity by studying herbivores feeding on the same plant species exposed to different environmental or experimental conditions are rare. Further, we advocate the use of host‐specificity measures based on plant phylogeny. Existing data suggest that a minority of species in herbivore communities feed on a single plant species when alternative congeneric hosts are available. Thus, host plant range limits tend to coincide with those of plant genera, rather than species or suprageneric taxa. Host specificity among tropical herbivore guilds decreases in the sequence: granivores>leaf-miners>fructivores>leaf-chewers=sap-suckers>xylophages>root-feeders, thus paralleling patterns observed in temperate forests. Differences in host specificity between temperate and tropical forests are difficult to assess since data on tropical herbivores originate from recent field studies, whereas their temperate counterparts derive from regional host species lists, assembled over many years. No major increase in host specificity from temperate to tropical communities is evident. This conclusion, together with the recent downward revisions of extremely high estimates of tropical species richness, suggest that tropical ecosystems may not be as biodiverse as previously thought.

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