Leaf shelter construction by herbivorous insects can improve leaf quality, sometimes changing resultant herbivory. In two experiments in a Missouri (USA) deciduous forest we quantified the impact of leaf tie construction and changes to leaf quality on subsequent leaf damage. First, using eight Second, we created experimental leaf ties, protected from herbivores, on the same
Shelter building caterpillars act as ecosystem engineers by creating and maintaining leaf shelters, which are then colonized by other arthropods. Foliage quality has been shown to influence initial colonization by shelter-building caterpillars. However, the effects of plant quality on the interactions between ecosystem engineers and their communities have yet to be studied at the whole plant level. We examined how leaf tying caterpillars, as ecosystem engineers, impact arthropod communities on
- NSF-PAR ID:
- 10460132
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Oecologia
- Volume:
- 203
- Issue:
- 1-2
- ISSN:
- 0029-8549
- Format(s):
- Medium: X Size: p. 13-25
- Size(s):
- ["p. 13-25"]
- Sponsoring Org:
- National Science Foundation
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Abstract Quercus species, we compared damage to single leaves versus experimental leaf ties that had been stocked with eitherPseudotelphusa quercinigracella (Gelechiidae) orPsilocorsis cryptolechiella (Depressariidae) to determine how initial leaf quality (total phenolics) influenced damage caused by shelter inhabitants. Skeletonization by leaf tying caterpillars and leaf edge chewing by free feeding species were 12.2× and 1.3× greater on tied than on non‐tied leaves, respectively. July and September leaf phenolic content had a slight positive effect on the probability of skeletonization, none on the probability of edge damage, and a weakly positive or negative effect on the intensity of skeletonization and edge damage, depending on leaf position.Quercus species to determine whether tie formation changes leaf quality (total phenolics, nitrogen, water, toughness). Tie formation decreased phenolics, but this change was predicted to add only 0.8% leaf area loss.Synthesis. Herbivory increased dramatically when leaves were in ties, with the effect mostly due to the tie itself rather than a change in leaf quality. We predict that the advantages of building and using leaf ties in this system are more likely to be escape from natural enemies and changes in abiotic factors. -
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Abstract Question It has been established that community biodiversity has consequences for ecosystem function. Yet research assessing these biodiversity–ecosystem function (
BEF ) relationships usually occurs at only one phylogenetic scale; as such, the dependence ofBEF relationships on phylogenetic scale has not been characterized. We present a novel framework for considering the consequences of biodiversity across phylogenetic scales, allowing us to ask: Do the consequences of intraspecific and interspecific diversity affect the growth, survival, and leaf herbivory of three temperate tree species?Study site Salicaceous tree plantation, Minnesota, northern USA.
Methods We established an experimental plantation consisting of trees of three species within the willow (Salicaceae) family. Two aspen (
Populus tremuloides ,P. alba ) and one willow (Salix nigra ) species were represented by three unique genotypes such that tree neighborhoods varied both in genotype richness (intraspecific diversity) and species richness (interspecific diversity). We assessed the consequences of tree identity and diversity across these two phylogenetic scales for all trees’ aboveground productivity and survival, and for herbivore damage (onP. tremuloides ) at the end of the second full growing season of the experiment.Results Diversity at any phylogenetic scale had no effect on the growth and survival of
P. alba orS. nigra . However, intraspecific diversity increased the likelihood ofP. tremuloides survival while interspecific diversity reducedP. tremuloides survival. Intraspecific diversity also reduced leaf removal and galling herbivory onP. tremuloides , while interspecific diversity had no effect on leaf removal and increased galling herbivory. Neither scale of diversity affected leaf mining.Conclusions Tree diversity within and among populations and species affected plant performance and ecosystem properties differentially, demonstrating that
BEF relationships shift across phylogenetic scales in a taxon‐specific manner. We call for further experiments that explicitly span these scales by measuring ecosystem and physiological responses to the manipulation of diversity within and among species. -
Climate models for the northeastern United States (U.S.) over the next century predict an increase in air temperature between 2.8 and 4.3 °C and a decrease in the average number of days per year when a snowpack will cover the forest floor (Hayhoe et al. 2007, 2008; Campbell et al. 2010). Studies of forest dynamics in seasonally snow-covered ecosystems have been primarily conducted during the growing season, when most biological activity occurs. However, in recent years considerable progress has been made in our understanding of how winter climate change influences dynamics in these forests. The snowpack insulates soil from below-freezing air temperatures, which facilitates a significant amount of microbial activity. However, a smaller snowpack and increased depth and duration of soil frost amplify losses of dissolved organic C and NO3- in leachate, as well as N2O released into the atmosphere. The increase in nutrient loss following increased soil frost cannot be explained by changes in microbial activity alone. More likely, it is caused by a decrease in plant nutrient uptake following increases in soil frost. We conducted a snow-removal experiment at Hubbard Brook Experimental Forest to determine the effects of a smaller winter snowpack and greater depth and duration of soil frost on trees, soil microbes, and arthropods. A number of publications have been based on these data: Comerford et al. 2013, Reinmann et al. 2019, Templer 2012, and Templer et al. 2012. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. Campbell JL, Ollinger SV, Flerchinger GN, Wicklein H, Hayhoe K, Bailey AS. Past and projected future changes in snowpack and soil frost at the Hubbard Brook Experimental Forest, New Hampshire, USA. Hydrological Processes. 2010; 24:2465–2480. Comerford DP, PG Schaberg, PH Templer, AM Socci, JL Campbell, and KF Wallin. 2013. Influence of experimental snow removal on root and canopy physiology of sugar maple trees in a northern hardwood forest. Oecologia 171:261-269. Hayhoe K, Wake CP, Huntington TG, Luo LF, Schwartz MD, Sheffield J, et al. Past and future changes in climate and hydrological indicators in the US Northeast. Climate Dynamics. 2007; 28:381–407. Hayhoe, K., Wake, C., Anderson, B. et al. Regional climate change projections for the Northeast USA. Mitig Adapt Strateg Glob Change 13, 425–436 (2008). https://doi.org/10.1007/s11027-007-9133-2. Reinmann AB, J Susser, EMC Demaria, PH Templer. 2019. Declines in northern forest tree growth following snowpack decline and soil freezing. Global Change Biology 25:420-430. Templer PH. 2012. Changes in winter climate: soil frost, root injury, and fungal communities (Invited). Plant and Soil 35: 15-17 Templer PH , AF Schiller, NW Fuller, AM Socci, JL Campbell, JE Drake, and TH Kunz. 2012. Impact of a reduced winter snowpack on litter arthropod abundance and diversity in a northern hardwood forest ecosystem. Biology and Fertility of Soils 48:413-424.more » « less
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null (Ed.)Although genetic diversity within stands of trees is known to have community-level consequences, whether such effects are present at an even finer genetic scale is unknown. We examined the hypothesis that genetic variability (heterozygosity) within an individual plant would affect its dependent community, which adds a new dimension to the importance of genetic diversity. Our study contrasted foliar arthropod community diversity and microsatellite marker-derived measures of genetic diversity of cottonwood (Populus fremontii) trees that had been felled by beavers (Castor canadensis) and were resprouting, relative to adjacent standing, unfelled trees. Three patterns emerged: 1. Productivity (specific leaf area), phytochemical defenses (salicortin), and arthropod community richness, abundance, and diversity were positively correlated with the heterozygosity of individual felled trees, but not with that of unfelled trees; 2. These relationships were not explained by population substructure, genetic relatedness of the trees, or hybridization; 3. The underlying mechanism appears to be that beaver herbivory stimulates increased productivity (i.e., 2× increase from the most homozygous to the most heterozygous tree) that is the greatest in more heterozygous trees. Salicortin defenses in twigs were also expressed at higher concentrations in more heterozygous trees (i.e., 3× increase from the most homozygous to the most heterozygous tree), which suggests that this compound may dissuade further herbivory by beavers, as has been found for other mammalian herbivores. We suggest that high stress to trees as a consequence of felling reveals a heterozygosity–productivity linkage, which in turn is attractive to arthropods. Although experiments are required to demonstrate causality, these results link the genetic diversity of individual trees to community diversity, supporting the hypothesis that interactions among foundation species (beavers and trees) have community-level effects, and underscores the importance of genetic diversity for biodiversity, conservation, and restoration.more » « less
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Abstract Biodiversity losses have increased in tropical forests due to fire‐related disturbances. As landscape fragmentation and climate change increase, fires will become more frequent and widespread across tropical rain forests worldwide, with important implications for forest dynamics by altering plant–animal interactions. Here we tested the hypothesis that recurrent fires in tropical rain forests change bottom‐up and top‐down forces controlling the abundance of insect herbivores, which in turn increases herbivory. To quantify herbivory, we collected 50 leaves per tree of five species in burned and unburned experimental plots (
N = 75) in southeastern Amazonian forests. We measured leaf nitrogen content and leaf thickness of tree leaves as bottom‐up factors that could explain differences in herbivory; we measured predation pressure on model caterpillars and estimated the abundance of predatory ants as top‐down factors. We found higher herbivory in burned than in unburned forests, as well as lower predator attacks in caterpillar models and lower abundance of predatory ants. Leaf nitrogen content did not vary across treatments. Birds attacked model caterpillars more frequently in burned than in unburned forests, and leaf thickness was higher in burned forests, but these factors together were not enough to offset the higher herbivory in burned plots. Fire degrades tropical forests not only by killing trees and altering their structure and community dynamics, but also by reducing predatory arthropods and disrupting predator–prey interactions, which triggers increased herbivory. These indirect impacts of recurrent fires probably contribute to further alter forest structure, functioning, and to decrease regeneration in Amazonian forests.Abstract in Portuguese is available with online material.
