Environmental factors influencing immigration behaviour of the invasive earthworm Lumbricus terrestris

Despite the ecological threats posed to northeastern North American forests by the invasive earthworm Lumbricus terrestris L., 1758 (Oligochaeta: Lumbricidae), the dispersal behaviour of this organism is poorly understood. This study investigated how environmental conditions influence the immigration behaviour of L. terrestris. Experimental mesocosms were used to test for differences in burrow establishment depending on leaf-litter type (sugar maple (Acer saccharum Marsh.) or white pine (Pinus strobus L.)) or the background population density of conspecifics (0, 25, or 100 m−2). Choice chambers were used to test for selection between habitat conditions. Video recording was used to measure the latency between introduction and establishment. A significantly greater proportion of individuals established burrows in the presence of maple over pine litter, although this preference did not result in a significant difference in latency. For higher population density treatments, the time since establishment of the background population of conspecifics had a significant effect on earthworm habitat selection, with an increasing preference for the high-density habitat over time. Population density had a significant effect on latency, with greater latency under low-density conditions. These results suggest that L. terrestris detects differences in litter type and conspecific population density and modifies its immigration behaviour accordingly. Findings may be useful in predicting and responding to future dispersal patterns of this invader.

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Leaf- and plant-level carbon gain in yellow birch, sugar maple, and beech seedlings from contrasting forest light environments

Canadian Journal of Forest Research ◽

10.1139/x99-220 ◽

2000 ◽

Vol 30 (3) ◽

pp. 390-404 ◽

Cited By ~ 21

Author(s):

Marilou Beaudet ◽

Christian Messier ◽

David W Hilbert ◽

Ernest Lo ◽

Zhang M Wang ◽

...

Keyword(s):

Acer Saccharum ◽

Sugar Maple ◽

Light Availability ◽

Fagus Grandifolia ◽

Carbon Gain ◽

Betula Alleghaniensis ◽

Yellow Birch ◽

Significant Difference ◽

Leaf Level ◽

Plant Level

Leaf-level photosynthetic-light response and plant-level daily carbon gain were estimated for seedlings of moderately shade-tolerant yellow birch (Betula alleghaniensis Britton) and shade-tolerant sugar maple (Acer saccharum Marsh.) and beech (Fagus grandifolia Ehrh.) growing in gaps and under a closed canopy in a sugar maple stand at Duchesnay, Que. All three species had a higher photosynthetic capacity (Amax) in the gaps than in shade, but yellow birch and beech responded more markedly than sugar maple to the increase in light availability. The high degree of plasticity observed in beech suggests that the prediction that photosynthetic plasticity should decrease with increasing shade tolerance may not hold when comparisons are made among a few late-successional species. Unit-area daily carbon gain (CA) was significantly higher in the gaps than in shade for all three species, but no significant difference was observed between light environments for plant-level carbon gain (CW). In shade, we found no difference of CA and CW among species. In gaps, beech had a significantly higher CA than sugar maple but similar to that of birch, and birch had a significantly higher CW than maple but similar to that of beech. Sugar maple consistently had lower carbon gains than yellow birch and beech but is nevertheless the dominant species at our study site. These results indicate that although plant-level carbon gain is presumably more closely related to growth and survival of a species than leaf-level photosynthesis, it is still many steps removed from the ecological success of a species.

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The Effect of Earthworm (Lumbricus terrestrisL.) Population Density and Soil Water Content Interactions on Nitrous Oxide Emissions from Agricultural Soils

Applied and Environmental Soil Science ◽

10.1155/2010/737096 ◽

2010 ◽

Vol 2010 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Andrew K. Evers ◽

Tyler A. Demers ◽

Andrew M. Gordon ◽

Naresh V. Thevathasan

Keyword(s):

Population Density ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Agricultural Soils ◽

Lumbricus Terrestris ◽

Nitrous Oxide Emissions ◽

Research Station ◽

Significant Difference ◽

The Relationship

Earthworms may have an influence on the production ofN2O, a greenhouse gas, as a result of the ideal environment contained in their gut and casts for denitrifier bacteria. The objective of this study was to determine the relationship between earthworm (Lumbricus terrestrisL.) population density, soil water content andN2Oemissions in a controlled greenhouse experiment based on population densities (90 to 270 individualsm−2) found at the Guelph Agroforestry Research Station (GARS) from 1997 to 1998. An experiment conducted at considerably higher than normal densities of earthworms revealed a significant relationship between earthworm density, soil water content andN2Oemissions, with mean emissions increasing to 43.5 gha−1day−1at 30 earthworms 0.0333 m−2at 35% soil water content. However, a second experiment, based on the density of earthworms at GARS, found no significant difference inN2Oemissions (5.49 to 6.99 gha−1day−1) aa a result of density and 31% soil water content.

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Long-term calcium addition increases growth release, wound closure, and health of sugar maple (Acer saccharum) trees at the Hubbard Brook Experimental Forest

Canadian Journal of Forest Research ◽

10.1139/x07-042 ◽

2007 ◽

Vol 37 (9) ◽

pp. 1692-1700 ◽

Cited By ~ 53

Author(s):

Brett A. Huggett ◽

Paul G. Schaberg ◽

Gary J. Hawley ◽

Christopher Eagar

Keyword(s):

Acer Saccharum ◽

Sugar Maple ◽

Wound Closure ◽

Hubbard Brook Experimental Forest ◽

Hubbard Brook ◽

Ca Addition ◽

Significant Difference ◽

Al Addition ◽

And Control

We surveyed and wounded forest-grown sugar maple ( Acer saccharum Marsh.) trees in a long-term, replicated Ca manipulation study at the Hubbard Brook Experimental Forest in New Hampshire, USA. Plots received applications of Ca (to boost Ca availability above depleted ambient levels) or Al (to compete with Ca uptake and further reduce Ca availability). We found significantly greater total foliar and membrane-associated Ca in foliage of trees in plots fertilized with Ca when compared with trees from Al-addition and control plots (P = 0.005). Coinciding with foliar Ca differences, trees exhibited a significant difference in crown vigor and in percent branch dieback among treatments (P < 0.05), with a trend towards improved canopy health as Ca levels increased. Annual basal area increment growth for the years following treatment initiation (1998–2004) was significantly greater in trees subjected to Ca addition compared with trees in control and Al treatments. Treatment-related improvements in growth were particularly evident after overstory release following a 1998 ice storm. The amount of wound closure was also greatest for trees in Ca-addition plots relative to Al-addition and control plots (P = 0.041). These findings support evidence that ambient Ca depletion is an important limiting factor regarding sugar maple health and highlight the influence of Ca on wound closure and growth following release from competition.

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