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Alonso‐Crespo IM, Hernández‐Agüero JA. Shedding light on trophic interactions: A field experiment on the effect of human population between latitudes on herbivory and predation patterns. Ecol Evol 2023; 13:e10449. [PMID: 37664505 PMCID: PMC10468994 DOI: 10.1002/ece3.10449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/25/2023] [Accepted: 08/09/2023] [Indexed: 09/05/2023] Open
Abstract
Interactions between species within an ecosystem (e.g. predation and herbivory) play a vital role in sustaining the ecosystem functionality, which includes aspects like pest control and nutrient cycling. Unfortunately, human activities are progressively disrupting these trophic relationships, thereby contributing to the ongoing biodiversity decline. Additionally, certain human activities like urbanization may further impact the intensity of these trophic interactions, which are already known to be influenced by latitudinal gradients. The aim of this study was to test the hypothesis of whether the impact of human population, used as a proxy for human pressure, differs between latitudes. To test it, we selected 18 study sites at two latitudes (i.e. ~53°N and ~50°N) with varying human population density (HPD). We used artificial caterpillars placed on European beech branches to assess bird predation and took standardized pictures of the leaves to estimate insect herbivory. Remote sensing techniques were used to estimate human pressure. We found that the intensity of bird predation varied in response to HPD, with opposite trends observed depending on the latitude. At our upper latitude, bird predation increased with HPD, while the opposite was observed at the lower latitude. Herbivory was not affected by urbanization and we found higher levels of herbivory in the lower compared to the higher latitude. At the lower latitude, certain species may experience a disadvantage attributed to the urban heat island effect due to their sensitivity to temperature fluctuations. Conversely, at the higher latitude, where minimum temperatures can be a limitation, certain species may benefit from milder winters. Overall, this study highlights the complex and dynamic nature of trophic relationships in the face of human-driven changes to ecosystems. It also emphasizes the importance of considering both human pressure and latitudinal gradients when assessing the ecological consequences of future climate change scenarios, especially in urban environments.
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Affiliation(s)
| | - Juan Antonio Hernández‐Agüero
- Senckenberg Gesellschaft für NaturforschungFrankfurt (am Main)Germany
- Department of Environmental GeographyVrije Universiteit AmsterdamAmsterdamThe Netherlands
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2
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Bowler DE, Kvasnes MAJ, Pedersen HC, Sandercock BK, Nilsen EB. Impacts of predator-mediated interactions along a climatic gradient on the population dynamics of an alpine bird. Proc Biol Sci 2020; 287:20202653. [PMID: 33352076 PMCID: PMC7779518 DOI: 10.1098/rspb.2020.2653] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
According to classic theory, species' population dynamics and distributions are less influenced by species interactions under harsh climatic conditions compared to under more benign climatic conditions. In alpine and boreal ecosystems in Fennoscandia, the cyclic dynamics of rodents strongly affect many other species, including ground-nesting birds such as ptarmigan. According to the ‘alternative prey hypothesis’ (APH), the densities of ground-nesting birds and rodents are positively associated due to predator–prey dynamics and prey-switching. However, it remains unclear how the strength of these predator-mediated interactions change along a climatic harshness gradient in comparison with the effects of climatic variation. We built a hierarchical Bayesian model to estimate the sensitivity of ptarmigan populations to interannual variation in climate and rodent occurrence across Norway during 2007–2017. Ptarmigan abundance was positively linked with rodent occurrence, consistent with the APH. Moreover, we found that the link between ptarmigan abundance and rodent dynamics was strongest in colder regions. Our study highlights how species interactions play an important role in population dynamics of species at high latitudes and suggests that they can become even more important in the most climatically harsh regions.
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Affiliation(s)
- Diana E Bowler
- Department of Ecosystem Services, German Centre for Integrative Biodiversity Research (iDiv), Putschstr. 4, 04103 Leipzig, Germany.,Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, 07743 Jena, Germany.,Department of Ecosystem Services, Helmholtz Center for Environmental Research-UFZ, Permoserstraße 15, 04318 Leipzig, Germany.,Department of Terrestrial Biodiversity, Norwegian Institute for Nature Research, P.O. 5685 Torgarden, 7485 Trondheim, Norway
| | - Mikkel A J Kvasnes
- Department of Terrestrial Biodiversity, Norwegian Institute for Nature Research, P.O. 5685 Torgarden, 7485 Trondheim, Norway
| | - Hans C Pedersen
- Department of Terrestrial Biodiversity, Norwegian Institute for Nature Research, P.O. 5685 Torgarden, 7485 Trondheim, Norway
| | - Brett K Sandercock
- Department of Terrestrial Biodiversity, Norwegian Institute for Nature Research, P.O. 5685 Torgarden, 7485 Trondheim, Norway
| | - Erlend B Nilsen
- Department of Terrestrial Biodiversity, Norwegian Institute for Nature Research, P.O. 5685 Torgarden, 7485 Trondheim, Norway.,Nord University, Faculty of Biosciences and Aquaculture, Steinkjer, Norway
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3
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Kristensen JA, Michelsen A, Metcalfe DB. Background insect herbivory increases with local elevation but makes minor contribution to element cycling along natural gradients in the Subarctic. Ecol Evol 2020; 10:11684-11698. [PMID: 33144993 PMCID: PMC7593201 DOI: 10.1002/ece3.6803] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 08/24/2020] [Accepted: 08/27/2020] [Indexed: 11/19/2022] Open
Abstract
Herbivores can exert major controls over biogeochemical cycling. As invertebrates are highly sensitive to temperature shifts (ectothermal), the abundances of insects in high-latitude systems, where climate warming is rapid, is expected to increase. In subarctic mountain birch forests, research has focussed on geometrid moth outbreaks, while the contribution of background insect herbivory (BIH) to elemental cycling is poorly constrained. In northern Sweden, we estimated BIH along 9 elevational gradients distributed across a gradient in regional elevation, temperature, and precipitation to allow evaluation of consistency in local versus regional variation. We converted foliar loss via BIH to fluxes of C, nitrogen (N), and phosphorus (P) from the birch canopy to the soil to compare with other relevant soil inputs of the same elements and assessed different abiotic and biotic drivers of the observed variability. We found that leaf area loss due to BIH was ~1.6% on average. This is comparable to estimates from tundra, but considerably lower than ecosystems at lower latitudes. The C, N, and P fluxes from canopy to soil associated with BIH were 1-2 orders of magnitude lower than the soil input from senesced litter and external nutrient sources such as biological N fixation, atmospheric deposition of N, and P weathering estimated from the literature. Despite the minor contribution to overall elemental cycling in subarctic birch forests, the higher quality and earlier timing of the input of herbivore deposits to soils compared to senesced litter may make this contribution disproportionally important for various ecosystem functions. BIH increased significantly with leaf N content as well as local elevation along each transect, yet showed no significant relationship with temperature or humidity, nor the commonly used temperature proxy, absolute elevation. The lack of consistency between the local and regional elevational trends calls for caution when using elevation gradients as climate proxies.
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Affiliation(s)
- Jeppe A. Kristensen
- Department of Physical Geography and Ecosystem ScienceLund UniversityLundSweden
- Geological Survey of Denmark and GreenlandCopenhagenDenmark
| | - Anders Michelsen
- Department of BiologyTerrestrial Ecology SectionUniversity of CopenhagenCopenhagenDenmark
- Center for PermafrostUniversity of CopenhagenCopenhagenDenmark
| | - Daniel B. Metcalfe
- Department of Physical Geography and Ecosystem ScienceLund UniversityLundSweden
- Department of Ecology and Environmental SciencesUmeå Umeå UniversitetUmeåSweden
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4
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Insect herbivory dampens Subarctic birch forest C sink response to warming. Nat Commun 2020; 11:2529. [PMID: 32439857 PMCID: PMC7242322 DOI: 10.1038/s41467-020-16404-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 04/27/2020] [Indexed: 11/21/2022] Open
Abstract
Climate warming is anticipated to make high latitude ecosystems stronger C sinks through increasing plant production. This effect might, however, be dampened by insect herbivores whose damage to plants at their background, non-outbreak densities may more than double under climate warming. Here, using an open-air warming experiment among Subarctic birch forest field layer vegetation, supplemented with birch plantlets, we show that a 2.3 °C air and 1.2 °C soil temperature increase can advance the growing season by 1–4 days, enhance soil N availability, leaf chlorophyll concentrations and plant growth up to 400%, 160% and 50% respectively, and lead up to 122% greater ecosystem CO2 uptake potential. However, comparable positive effects are also found when insect herbivory is reduced, and the effect of warming on C sink potential is intensified under reduced herbivory. Our results confirm the expected warming-induced increase in high latitude plant growth and CO2 uptake, but also reveal that herbivorous insects may significantly dampen the strengthening of the CO2 sink under climate warming. Warming is expected to increase C sink capacity in high-latitude ecosystems, but plant-herbivore interactions could moderate or offset this effect. Here, Silfver and colleagues test individual and interactive effects of warming and insect herbivory in a field experiment in Subarctic forest, showing that even low intensity insect herbivory strongly reduces C sink potential.
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5
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Accumulation of Urban Insect Pests in China: 50 Years’ Observations on Camphor Tree (Cinnamomum camphora). SUSTAINABILITY 2020. [DOI: 10.3390/su12041582] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Since China experienced a rapid and unprecedented process of urbanization and climate change from 1978 onwards, pest outbreaks were frequently reported on urban forests, which reflects a significant imbalance between natural regulation and human control. Based on information extracted from all journal articles and reports about insect pests on camphor tree (Cinnamomum camphora) in urban China, we characterized historical patterns and trends in pest outbreaks over large areas. Our results suggested that (1) most distribution areas of C. camphora in urban China had pest records (14 provinces) over the last 50 years, especially at the south-eastern coastal areas; (2) pests on camphor tree in urban China showed an accelerated growth since the 1990s; and (3) pests on camphor tree in urban China were characterized by native and leaf-feeding species. Urbanization seems to positively correlate with urban pest outbreaks. Changes of urban pest outbreaks could largely be described by synchronic changes of socio-economic indicators, of which CO2 emissions as metric tons per capita is the most significant predictor, followed by GDP and human population. Thus, managers and city planners should allocate resources to socio-economic-related pest outbreaks for a sustainable ecosystem.
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6
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Just MG, Dale AG, Long LC, Frank SD. Urbanization drives unique latitudinal patterns of insect herbivory and tree condition. OIKOS 2019. [DOI: 10.1111/oik.05874] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michael G. Just
- Dept of Entomology and Plant Pathology, North Carolina State University Raleigh NC 27695 USA
| | - Adam G. Dale
- Entomology and Nematology Dept, Univ. of Florida Gainesville FL USA
| | - Lawrence C. Long
- Dept of Entomology and Plant Pathology, North Carolina State University Raleigh NC 27695 USA
| | - Steven D. Frank
- Dept of Entomology and Plant Pathology, North Carolina State University Raleigh NC 27695 USA
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8
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Hunter MD, Kozlov MV. The relative strengths of rapid and delayed density dependence acting on a terrestrial herbivore change along a pollution gradient. J Anim Ecol 2018; 88:665-676. [PMID: 30471097 DOI: 10.1111/1365-2656.12930] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 10/26/2018] [Indexed: 11/30/2022]
Abstract
Animal populations vary in response to a combination of density-dependent and density-independent forces, which interact to drive their population dynamics. Understanding how abiotic forces mediate the form and strength of density-dependent processes remains a central goal of ecology, and is of increasing urgency in a rapidly changing world. Here, we report for the first time that industrial pollution determines the relative strength of rapid and delayed density dependence operating on an animal population. We explored the impacts of pollution and climate on the population dynamics of an eruptive leafmining moth, Phyllonorycter strigulatella, around a coal-fired power plant near Apatity, north-western Russia. Populations were monitored at 14 sites over 26 years. The relative strengths of rapid and delayed density dependence varied with distance from the power plant. Specifically, the strength of rapid density dependence increased while the strength of delayed density dependence decreased with increasing distance from the pollution source. Paralleling the increasing strength of rapid density dependence, we observed declines in the densities of P. strigulatella, increases in predation pressure from birds and ants, and declines in an unknown source of mortality (perhaps plant antibiosis) with increasing distance from the power plant. In contrast to the associations with pollution, associations between climate change and leafminer population densities were negligible. Our results may help to explain the outbreaks of insect herbivores that are frequently observed in polluted environments. We show that they can result from the weakening of rapid (stabilizing) density dependence relative to the effects of destabilizing delayed density dependence. Moreover, our results may explain some of the variation reported in published studies of animal populations in polluted habitats. Variable results may emerge in part because of the location of the study sites on different parts of pollution gradients. Finally, in a rapidly changing world, effects of anthropogenic pollution may be as, or more, important than are effects of climate change on the future dynamics of animal populations.
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Affiliation(s)
- Mark D Hunter
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan
| | - Mikhail V Kozlov
- Section of Ecology and Evolutionary Biology, Department of Biology, University of Turku, Turku, Finland
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9
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Nybakken L, Lie MH, Julkunen-Tiitto R, Asplund J, Ohlson M. Fertilization Changes Chemical Defense in Needles of Mature Norway Spruce ( Picea abies). FRONTIERS IN PLANT SCIENCE 2018; 9:770. [PMID: 29930566 PMCID: PMC6000156 DOI: 10.3389/fpls.2018.00770] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 05/18/2018] [Indexed: 05/29/2023]
Abstract
Nitrogen availability limits growth in most boreal forests. However, parts of the boreal zone receive significant levels of nitrogen deposition. At the same time, forests are fertilized to increase volume growth and carbon sequestration. No matter the source, increasing nitrogen in the boreal forest ecosystem will influence the resource situation for its primary producers, the plants, with possible implications for their defensive chemistry. In general, fertilization reduces phenolic compound concentrations in trees, but existing evidence mainly comes from studies on young plants. Given the role of the phenolic compounds in protection against herbivores and other forest pests, it is important to know if phenolics are reduced with fertilization also in mature trees. The evergreen Norway spruce is long-lived, and it is reasonable that defensive strategies could change from the juvenile to the reproductive and mature phases. In addition, as the needles are kept for several years, defense could also change with needle age. We sampled current and previous year needles from an N fertilization experiment in a Norway spruce forest landscape in south-central Norway to which N had been added annually for 13 years. We analyzed total nitrogen (N) and carbon (C), as well as low-molecular phenolics and condensed tannins. Needles from fertilized trees had higher N than those from controls plots, and fertilization decreased concentrations of many flavonoids, as well as condensed tannins in current year needles. In previous year needles, some stilbenes and condensed tannins were higher in fertilized trees. In control trees, the total phenolic concentration was almost five times as high in previous year needles compared with those from the current year, and there were great compositional differences. Previous year needles contained highest concentrations of acetophenone and stilbenes, while in the current year needles the flavonoids, and especially coumaroyl-astragalins dominated. Condensed tannins did not differ between current and previous year needles from control trees. In conclusion, the phenolic defense of current year needles of mature P.abies trees was strongly changed upon fertilization. This may imply that nitrogen deposition and forest fertilization leave forests less robust in a time when pests may take advantages of a changing climate.
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Affiliation(s)
- Line Nybakken
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Akershus, Norway
| | - Marit H. Lie
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Akershus, Norway
| | - Riitta Julkunen-Tiitto
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
| | - Johan Asplund
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Akershus, Norway
| | - Mikael Ohlson
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Akershus, Norway
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10
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Meineke E, Youngsteadt E, Dunn RR, Frank SD. Urban warming reduces aboveground carbon storage. Proc Biol Sci 2017; 283:rspb.2016.1574. [PMID: 27708149 DOI: 10.1098/rspb.2016.1574] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 09/16/2016] [Indexed: 11/12/2022] Open
Abstract
A substantial amount of global carbon is stored in mature trees. However, no experiments to date test how warming affects mature tree carbon storage. Using a unique, citywide, factorial experiment, we investigated how warming and insect herbivory affected physiological function and carbon sequestration (carbon stored per year) of mature trees. Urban warming increased herbivorous arthropod abundance on trees, but these herbivores had negligible effects on tree carbon sequestration. Instead, urban warming was associated with an estimated 12% loss of carbon sequestration, in part because photosynthesis was reduced at hotter sites. Ecosystem service assessments that do not consider urban conditions may overestimate urban tree carbon storage. Because urban and global warming are becoming more intense, our results suggest that urban trees will sequester even less carbon in the future.
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Affiliation(s)
- Emily Meineke
- Department of Entomology, North Carolina State University, Raleigh, NC 27695-7613, USA
| | - Elsa Youngsteadt
- Department of Entomology, North Carolina State University, Raleigh, NC 27695-7613, USA
| | - Robert R Dunn
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695-7613, USA University of Copenhagen Center for Macroecology, Evolution, and Climate, 2100 Copenhagen, Denmark
| | - Steven D Frank
- Department of Entomology, North Carolina State University, Raleigh, NC 27695-7613, USA
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11
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Kozlov MV, Zverev V, Zvereva EL. Combined effects of environmental disturbance and climate warming on insect herbivory in mountain birch in subarctic forests: Results of 26-year monitoring. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 601-602:802-811. [PMID: 28578238 DOI: 10.1016/j.scitotenv.2017.05.230] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/17/2017] [Accepted: 05/25/2017] [Indexed: 06/07/2023]
Abstract
Both pollution and climate affect insect-plant interactions, but the combined effects of these two abiotic drivers of global change on insect herbivory remain almost unexplored. From 1991 to 2016, we monitored the population densities of 25 species or species groups of insects feeding on mountain birch (Betula pubescens ssp. czerepanovii) in 29 sites and recorded leaf damage by insects in 21 sites in subarctic forests around the nickel-copper smelter at Monchegorsk, north-western Russia. The leaf-eating insects demonstrated variable, and sometimes opposite, responses to pollution-induced forest disturbance and to climate variations. Consequently, we did not discover any general trend in herbivory along the disturbance gradient. Densities of eight species/species groups correlated with environmental disturbance, but these correlations weakened from 1991 to 2016, presumably due to the fivefold decrease in emissions of sulphur dioxide and heavy metals from the smelter. The densities of externally feeding defoliators decreased from 1991 to 2016 and the densities of leafminers increased, while the leaf roller densities remained unchanged. Consequently, no overall temporal trend in the abundance of birch-feeding insects emerged despite a 2-3°C elevation in spring temperatures. Damage to birch leaves by insects decreased during the observation period in heavily disturbed forests, did not change in moderately disturbed forests and tended to increase in pristine forests. The temporal stability of insect-plant interactions, quantified by the inverse of the coefficient of among-year variations of herbivore population densities and of birch foliar damage, showed a negative correlation with forest disturbance. We conclude that climate differently affects insect herbivory in heavily stressed versus pristine forests, and that herbivorous insects demonstrate diverse responses to environmental disturbance and climate variations. This diversity of responses, in combination with the decreased stability of insect-plant interactions, increases the uncertainty in predictions on the impacts of global change on forest damage by insects.
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Affiliation(s)
- M V Kozlov
- Section of Ecology, Department of Biology, University of Turku, FI-20014 Turku, Finland.
| | - V Zverev
- Section of Ecology, Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - E L Zvereva
- Section of Ecology, Department of Biology, University of Turku, FI-20014 Turku, Finland
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12
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Ferrenberg S, Langenhan JM, Loskot SA, Rozal LM, Mitton JB. Resin monoterpene defenses decline within three widespread species of pine (Pinus) along a 1530-m elevational gradient. Ecosphere 2017. [DOI: 10.1002/ecs2.1975] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Scott Ferrenberg
- Department of Biology; New Mexico State University; Las Cruces New Mexico 88003 USA
| | | | - Steven A. Loskot
- Department of Chemistry; Seattle University; Seattle Washington 98122 USA
| | - Leonardo M. Rozal
- Department of Chemistry; Seattle University; Seattle Washington 98122 USA
| | - Jeffry B. Mitton
- Department of Ecology and Evolutionary Biology; University of Colorado; Boulder Colorado 80309 USA
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13
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Kozlov MV, Lanta V, Zverev V, Rainio K, Kunavin MA, Zvereva EL. Decreased losses of woody plant foliage to insects in large urban areas are explained by bird predation. GLOBAL CHANGE BIOLOGY 2017; 23:4354-4364. [PMID: 28317226 DOI: 10.1111/gcb.13692] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/27/2017] [Accepted: 03/04/2017] [Indexed: 06/06/2023]
Abstract
Despite the increasing rate of urbanization, the consequences of this process on biotic interactions remain insufficiently studied. Our aims were to identify the general pattern of urbanization impact on background insect herbivory, to explore variations in this impact related to characteristics of both urban areas and insect-plant systems, and to uncover the factors governing urbanization impacts on insect herbivory. We compared the foliar damage inflicted on the most common trees by defoliating, leafmining and gall-forming insects in rural and urban habitats associated with 16 European cities. In two of these cities, we explored quality of birch foliage for herbivorous insects, mortality of leafmining insects due to predators and parasitoids and bird predation on artificial plasticine larvae. On average, the foliage losses to insects were 16.5% lower in urban than in rural habitats. The magnitude of the overall adverse effect of urbanization on herbivory was independent of the latitude of the locality and was similar in all 11 studied tree species, but increased with an increase in the size of the urban area: it was significant in large cities (city population 1-5 million) but not significant in medium-sized and small towns. Quality of birch foliage for herbivorous insects was slightly higher in urban habitats than in rural habitats. At the same time, leafminer mortality due to ants and birds and the bird attack intensity on dummy larvae were higher in large cities than in rural habitats, which at least partially explained the decline in insect herbivory observed in response to urbanization. Our findings underscore the importance of top-down forces in mediating impacts of urbanization on plant-feeding insects: factors favouring predators may override the positive effects of temperature elevation on insects and thus reduce plant damage.
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Affiliation(s)
- Mikhail V Kozlov
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
| | - Vojtěch Lanta
- Laboratory of Cell Cycles of Algae, Institute of Microbiology, Czech Academy of Sciences, Třeboň, Czech Republic
| | - Vitali Zverev
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
| | - Kalle Rainio
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
| | - Mikhail A Kunavin
- Department of Human Physiology and Morphology, High School of Natural Sciences and Technologies, Northern (Arctic) Federal University, Arkhangelsk, Russia
| | - Elena L Zvereva
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
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14
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Zverev V, Zvereva EL, Kozlov MV. Ontogenetic changes in insect herbivory in birch (
Betula pubesecens
): The importance of plant apparency. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12920] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vitali Zverev
- Section of EcologyDepartment of BiologyUniversity of Turku Turku Finland
| | - Elena L. Zvereva
- Section of EcologyDepartment of BiologyUniversity of Turku Turku Finland
| | - Mikhail V. Kozlov
- Section of EcologyDepartment of BiologyUniversity of Turku Turku Finland
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15
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Warming and drought combine to increase pest insect fitness on urban trees. PLoS One 2017; 12:e0173844. [PMID: 28278206 PMCID: PMC5344462 DOI: 10.1371/journal.pone.0173844] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 02/27/2017] [Indexed: 11/30/2022] Open
Abstract
Urban habitats are characterized by impervious surfaces, which increase temperatures and reduce water availability to plants. The effects of these conditions on herbivorous insects are not well understood, but may provide insight into future conditions. Three primary hypotheses have been proposed to explain why multiple herbivorous arthropods are more abundant and damaging in cities, and support has been found for each. First, less complex vegetation may reduce biological control of pests. Second, plant stress can increase plant quality for pests. And third, urban warming can directly increase pest fitness and abundance. These hypotheses are not mutually exclusive, and the effects of temperature and plant stress are particularly related. Thus, we test the hypothesis that urban warming and drought stress combine to increase the fitness and abundance of the scale insect, Melanaspis tenebricosa, an urban tree pest that is more abundant in urban than rural areas of the southeastern U.S. We did this by manipulating drought stress across an existing mosaic of urban warming. We found support for the additive effect of temperature and drought stress such that female embryo production and body size increased with temperature and was greater on drought-stressed than watered trees. This study provides further evidence that drivers of pest insect outbreaks act in concert, rather than independently, and calls for more research that manipulates multiple abiotic factors related to urbanization and climate change to predict their effects on ecological interactions. As cities expand and the climate changes, warmer temperatures and drought conditions may become more widespread in the native range of this pest. These changes have direct physiological benefits for M. tenebricosa, and potentially other pests, that may increase their fitness and abundance in urban and natural forests.
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16
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Bhattarai GP, Meyerson LA, Anderson J, Cummings D, Allen WJ, Cronin JT. Biogeography of a plant invasion: genetic variation and plasticity in latitudinal clines for traits related to herbivory. ECOL MONOGR 2016. [DOI: 10.1002/ecm.1233] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Ganesh P. Bhattarai
- Department of Biological Sciences Louisiana State University Baton Rouge Louisiana 70803 USA
| | - Laura A. Meyerson
- Department of Natural Resource Sciences University of Rhode Island 1 Greenhouse Road Kingston Rhode Island 02881 USA
| | - Jack Anderson
- Department of Natural Resource Sciences University of Rhode Island 1 Greenhouse Road Kingston Rhode Island 02881 USA
| | - David Cummings
- Department of Natural Resource Sciences University of Rhode Island 1 Greenhouse Road Kingston Rhode Island 02881 USA
| | - Warwick J. Allen
- Department of Biological Sciences Louisiana State University Baton Rouge Louisiana 70803 USA
| | - James T. Cronin
- Department of Biological Sciences Louisiana State University Baton Rouge Louisiana 70803 USA
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Kozlov MV, Skoracka A, Zverev V, Lewandowski M, Zvereva EL. Two Birch Species Demonstrate Opposite Latitudinal Patterns in Infestation by Gall-Making Mites in Northern Europe. PLoS One 2016; 11:e0166641. [PMID: 27835702 PMCID: PMC5105990 DOI: 10.1371/journal.pone.0166641] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 11/01/2016] [Indexed: 11/19/2022] Open
Abstract
Latitudinal patterns in herbivory, i.e. variations in plant losses to animals with latitude, are generally explained by temperature gradients. However, earlier studies suggest that geographical variation in abundance and diversity of gall-makers may be driven by precipitation rather than by temperature. To test the above hypothesis, we examined communities of eriophyoid mites (Acari: Eriophyoidea) on leaves of Betula pendula and B. pubescens in boreal forests in Northern Europe. We sampled ten sites for each of five latitudinal gradients from 2008-2011, counted galls of six morphological types and identified mites extracted from these galls. DNA analysis revealed cryptic species within two of six morphologically defined mite species, and these cryptic species induced different types of galls. When data from all types of galls and from two birch species were pooled, the percentage of galled leaves did not change with latitude. However, we discovered pronounced variation in latitudinal changes between birch species. Infestation by eriophyoid mites increased towards the north in B. pendula and decreased in B. pubescens, while diversity of galls decreased towards the north in B. pendula and did not change in B. pubescens. The percentage of galled leaves did not differ among geographical gradients and study years, but was 20% lower in late summer relative to early summer, indicating premature abscission of infested leaves. Our data suggest that precipitation has little effect on abundance and diversity of eriophyoid mites, and that climate warming may impose opposite effects on infestation of two birch species by galling mites, favouring B. pendula near the northern tree limit.
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Affiliation(s)
- Mikhail V. Kozlov
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
- * E-mail:
| | - Anna Skoracka
- Population Ecology Laboratory, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - Vitali Zverev
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
| | - Mariusz Lewandowski
- Department of Applied Entomology, Faculty of Agriculture, Biotechnology and Landscape Architecture, Warsaw University of Life Sciences—SGGW, Warsaw, Poland
| | - Elena L. Zvereva
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
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Zvereva EL, Hunter MD, Zverev V, Kozlov MV. Factors affecting population dynamics of leaf beetles in a subarctic region: The interplay between climate warming and pollution decline. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 566-567:1277-1288. [PMID: 27266523 DOI: 10.1016/j.scitotenv.2016.05.187] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 05/26/2016] [Accepted: 05/26/2016] [Indexed: 06/06/2023]
Abstract
Understanding the mechanisms by which abiotic drivers, such as climate and pollution, influence population dynamics of animals is important for our ability to predict the population trajectories of individual species under different global change scenarios. We monitored four leaf beetle species (Coleoptera: Chrysomelidae) feeding on willows (Salix spp.) in 13 sites along a pollution gradient in subarctic forests of north-western Russia from 1993 to 2014. During a subset of years, we also measured the impacts of natural enemies and host plant quality on the performance of one of these species, Chrysomela lapponica. Spring and fall temperatures increased by 2.5-3°C during the 21-year observation period, while emissions of sulfur dioxide and heavy metals from the nickel-copper smelter at Monchegorsk decreased fivefold. However, contrary to predictions of increasing herbivory with climate warming, and in spite of discovered increase in host plant quality with increase in temperatures, none of the beetle species became more abundant during the past 20years. No directional trends were observed in densities of either Phratora vitellinae or Plagiodera versicolora, whereas densities of both C. lapponica and Gonioctena pallida showed a simultaneous rapid 20-fold decline in the early 2000s, remaining at very low levels thereafter. Time series analysis and model selection indicated that these abrupt population declines were associated with decreases in aerial emissions from the smelter. Observed declines in the population densities of C. lapponica can be explained by increases in mortality from natural enemies due to the combined action of climate warming and declining pollution. This pattern suggests that at least in some tri-trophic systems, top-down factors override bottom-up effects and govern the impacts of environmental changes on insect herbivores.
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Affiliation(s)
- Elena L Zvereva
- Section of Ecology, Department of Biology, University of Turku, Turku 20014, Finland.
| | - Mark D Hunter
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Vitali Zverev
- Section of Ecology, Department of Biology, University of Turku, Turku 20014, Finland
| | - Mikhail V Kozlov
- Section of Ecology, Department of Biology, University of Turku, Turku 20014, Finland
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Wang XF, Liu JF, Gao WQ, Deng YP, Ni YY, Xiao YH, Kang FF, Wang Q, Lei JP, Jiang ZP. Defense pattern of Chinese cork oak across latitudinal gradients: influences of ontogeny, herbivory, climate and soil nutrients. Sci Rep 2016; 6:27269. [PMID: 27252112 PMCID: PMC4890039 DOI: 10.1038/srep27269] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 05/09/2016] [Indexed: 11/09/2022] Open
Abstract
Knowledge of latitudinal patterns in plant defense and herbivory is crucial for understanding the mechanisms that govern ecosystem functioning and for predicting their responses to climate change. Using a widely distributed species in East Asia, Quercus variabilis, we aim to reveal defense patterns of trees with respect to ontogeny along latitudinal gradients. Six leaf chemical (total phenolics and total condensed tannin concentrations) and physical (cellulose, hemicellulose, lignin and dry mass concentration) defensive traits as well as leaf herbivory (% leaf area loss) were investigated in natural Chinese cork oak (Q. variabilis) forests across two ontogenetic stages (juvenile and mature trees) along a ~14°-latitudinal gradient. Our results showed that juveniles had higher herbivory values and a higher concentration of leaf chemical defense substances compared with mature trees across the latitudinal gradient. In addition, chemical defense and herbivory in both ontogenetic stages decreased with increasing latitude, which supports the latitudinal herbivory-defense hypothesis and optimal defense theory. The identified trade-offs between chemical and physical defense were primarily determined by environmental variation associated with the latitudinal gradient, with the climatic factors (annual precipitation, minimum temperature of the coldest month) largely contributing to the latitudinal defense pattern in both juvenile and mature oak trees.
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Affiliation(s)
- Xiao-Fei Wang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
| | - Jian-Feng Liu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
| | - Wen-Qiang Gao
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
| | - Yun-Peng Deng
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
| | - Yan-Yan Ni
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
| | - Yi-Hua Xiao
- The Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou 510520, China
| | - Feng-Feng Kang
- College of Forestry, Beijing Forestry University, Beijing 100083, China
| | - Qi Wang
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China
| | - Jing-Pin Lei
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
| | - Ze-Ping Jiang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
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Responses of community-level plant-insect interactions to climate warming in a meadow steppe. Sci Rep 2015; 5:18654. [PMID: 26686758 PMCID: PMC4685464 DOI: 10.1038/srep18654] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 11/23/2015] [Indexed: 11/21/2022] Open
Abstract
Climate warming may disrupt trophic interactions, consequently influencing ecosystem functioning. Most studies have concentrated on the temperature-effects on plant-insect interactions at individual and population levels, with a particular emphasis on changes in phenology and distribution. Nevertheless, the available evidence from the community level is limited. A 3-year field manipulative experiment was performed to test potential responses of plant and insect communities, and plant-insect interactions, to elevated temperature in a meadow steppe. Warming increased the biomass of plant community and forbs, and decreased grass biomass, indicating a shift from grass-dominant to grass-forb mixed plant community. Reduced abundance of the insect community under warming, particularly the herbivorous insects, was attributed to lower abundance of Euchorthippus unicolor and a Cicadellidae species resulting from lower food availability and higher defensive herbivory. Lower herbivore abundance caused lower predator species richness because of reduced prey resources and contributed to an overall decrease in insect species richness. Interestingly, warming enhanced the positive relationship between insect and plant species richness, implying that the strength of the plant-insect interactions was altered by warming. Our results suggest that alterations to plant-insect interactions at a community level under climate warming in grasslands may be more important and complex than previously thought.
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Kozlov MV, Filippov BY, Zubrij NA, Zverev V. Abrupt changes in invertebrate herbivory on woody plants at the forest–tundra ecotone. Polar Biol 2015. [DOI: 10.1007/s00300-015-1655-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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