An experimental test of facilitation between non-native earthworms

2011 ◽  
Vol 89 (12) ◽  
pp. 1223-1230 ◽  
Author(s):  
Erin K. Cameron ◽  
Erin M. Bayne

Invasional meltdowns, in which facilitation between species causes an accelerating increase in the number of introduced species or impacts, can cause large impacts in invaded systems. Earthworm invasion of northern forests has been suggested as a meltdown, with litter-dwelling species altering soil structure and facilitating mineral-soil or deep-burrowing earthworms that may be less capable of invading intact forest floors. We examined facilitation and synergistic effects of a litter-dwelling species ( Dendrobaena octaedra Savigny, 1826) and a deep-burrowing species ( Lumbricus terrestris L., 1758). Boreal forest soil cores were inoculated with D. octaedra, L. terrestris, both species, a higher density of L. terrestris, or no worms. After 4.5 months, we found no differences in survival or biomass between treatments for either species. Cocoon production did not differ for L. terrestris, but D. octaedra produced significantly fewer cocoons with L. terrestris. The two species had an additive effect on organic horizon depths and bulk densities. Thus, they did not appear to facilitate each other or have synergistic effects as would be predicted in an invasional meltdown.

2021 ◽  
Author(s):  
Hans-Jörg Vogel ◽  
Mar­ia Balseiro-Romero ◽  
Philippe C. Baveye ◽  
Alexandra Kravchenko ◽  
Wilfred Otten ◽  
...  

<p>Soil structure, lately referred to as the ''architecture'' is a key to explain and understand all soil functions. The development of sophisticated imaging techniques over the last decades has led to significant progress in the description of this architecture and in particular of the geometry of the hierarchically-branched pore space in which transport of water, gases, solutes and particles occurs and where myriads of organisms live. Moreover, there are sophisticated tools available today to also visualize the spatial structure of the solid phase including mineral grains and organic matter. Hence, we do have access to virtually all components of soil architecture.</p><p>Unfortunately, it has so far proven very challenging to study the dynamics of soil architecture over time, which is of critical importance for soil as habitat and the turnover of organic matter. Several largely conflicting theories have been proposed to account for this dynamics, especially the formation of aggregates. We review these theories, and we propose a conceptual approach to reconcile them based on a consistent interpretation of experimental observations and by integrating known physical and biogeochemical processes. A key conclusion is that rather than concentrating on aggregate formation in the sense of how particles and organic matter reorganize to form aggregates as distinct functional units we should focus on biophysical processes that produce a porous, heterogeneous organo-mineral soil matrix that breaks into fragments of different size and stability when exposed to mechanical stress.  The unified vision we propose for soil architecture and the mechanisms that determine its temporal evolution, should pave the way towards a better understanding of soil processes and functions.</p>


2007 ◽  
Vol 87 (1) ◽  
pp. 93-102 ◽  
Author(s):  
J M Kranabetter ◽  
A M Macadam

The extent of carbon (C) storage in forests and the change in C stocks after harvesting are important considerations in the management of greenhouse gases. We measured changes in C storage over time (from postharvest, postburn, year 5, year 10 and year 20) in logging slash, forest floors, mineral soils and planted lodgepole pine (Pinus contorta var. latifolia) trees from six prescribed-burn plantations in north central British Columbia. After harvest, site C in these pools averaged 139 Mg ha-1, with approximately equal contributions from mineral soils (0–30 cm), forest floors and logging slash. Together these detrital pools declined by 71 Mg C ha-1, or 51% (28% directly from the broadcast burn, and a further 23% postburn), in the subsequent 20 yr. Postburn decay in logging slash was inferred by reductions in wood density (from 0.40 to 0.34 g cm-3), equal to an average k rate of 0.011 yr-1. Losses in forest floor C, amounting to more than 60% of the initial mass, were immediate and continued to year 5, with no reaccumulation evident by year 20. Mineral soil C concentrations initially fluctuated before declining by 25% through years 10 and 20. Overall, the reductions in C storage were offset by biomass accumulation of lodgepole pine, and we estimate these plantations had become a net sink for C before year 20, although total C storage was still less than postharvest levels. Key words: C sequestration, forest floors; coarse woody debris; soil organic matter


1986 ◽  
Vol 16 (6) ◽  
pp. 1320-1326 ◽  
Author(s):  
K. Van Cleve ◽  
O. W. Heal ◽  
D. Roberts

Using a bioassay approach, this paper considers the nitrogen-supplying power of forest floors from examples of the major forest types in interior Alaska. Yield and net N uptake by paper birch seedlings grown in standardized mixtures of quartz sand and forest floor organic matter, and separate incubation estimates of N mineralization and nitrification for the forest floors, were employed to evaluate potential N supply. Black spruce and floodplain white spruce forest floors supplied only one-fifth the amount of N taken up by seedlings growing in other forest floors. Incubation estimates showed these forest floors yielded 4 and 15 times less extractable N, respectively, than the more fertile birch forest floors. In comparison with earlier estimates of P supply from these same forest floors, the upland types showed greater deficiency of N whereas floodplain types showed greater deficiency of P in control of seedling yield. The latter condition is attributed to the highly calcareous nature of the floodplain mineral soil, the consequent potential for P fixation, and hence greater potential deficiency of the element compared with N in mineralizing forest floors. Nitrogen concentration of the forest floors was the best predictor of bioassay response.


1984 ◽  
Vol 14 (6) ◽  
pp. 763-767 ◽  
Author(s):  
C. Anthony Federer

Organic content of the forest floor decreases for several years after clear-cutting, and then slowly recovers. Thickness, bulk density, organic matter, and nitrogen content of forest floors were measured for 13 northern hardwood stands in the White Mountains of New Hampshire. Stands ranged from 1 to about 100 years in age. Forest-floor thickness varied significantly with stand age, but bulk density, organic fraction, and nitrogen fraction were independent of age. Total organic content of the forest floor agreed very well with data from Covington's (W. W. Covington 1981. Ecology, 62: 41–48) study of the same area. Both studies indicated that mature forest floors have about 80 Mg organic matter•ha−1 and 1.9 Mg nitrogen•ha−1. Within 10 or 15 years after cutting, the organic matter content of the floor decreases to 50 Mg•ha−1, and its nitrogen content to 1.1 Mg•ha−1. The question whether the decrease is rapid and the minimum broad and flat, or if the decrease is gradual and the minimum sharp, cannot be answered. The subsequent increase to levels reached in mature forest requires about 50 years. Some of the initial decrease in organic matter and nitrogen content of the forest floor may be caused by organic decomposition and nitrogen leaching, but mechanical and chemical mixing of floor into mineral soil, during and after the harvest operation, may also be important. The difference is vital with respect to maintenance of long-term productivity.


1993 ◽  
Vol 23 (5) ◽  
pp. 970-978 ◽  
Author(s):  
K. Van Cleve ◽  
J. Yarie ◽  
R. Erickson ◽  
C.T. Dyrness

Nitrogen (N) mineralization and nitrification were compared among ecosystems representing a primary successional sequence on the Tanana River floodplain of interior Alaska. These processes displayed marked seasonality, were closely related to substrate chemistry, and reflected the impact of vegetation clearing. The highest rates of N mineralization were encountered in the June to July incubation periods, and rates generally declined during the remainder of the summer. The early season period (June to July) was the interval of most favorable litter and mineral soil temperature and most available energy supply for microbial mineralization of detrital materials. Minimal rates were encountered during the winter. Litter layer N mineralization rates were highest in the early-successional poplar–alder (Populusbalsamifera–Alnustenuifolia (Nutt.) stage and declined with advancing succession in poplar (Populusbalsamifera) and mature white spruce (Piceaglauca) (Moench) Voss) stands. The poplar–alder stage displayed the highest rate of nitrification. Nitrate constituted 98% of the mineralized N in early-successional poplar–alder forest floors but fell to 4 and 0% in poplar and white spruce forest floors, respectively. Nitrogen mineralization was closely related to significant increases in the lignin/N ratio across the sequence of vegetation types. The rate of surface mineral soil net N mineralization increased with succession in response to higher soil organic matter content. The range of average total seasonal net N mineralization (260–1600 mg N•m−2) for litter layer plus mineral soil among successional stages in this study was generally lower than the 1200–8400 mg N•m−2 reported by investigators for other studies in temperate latitudes. Vegetation clearing increased the magnitude of temporal fluxes as well as total annual mineral N production. The most consistent increases were encountered in the poplar–alder vegetation type. The average seasonal total net N mineralization for forest floor plus mineral soil in this vegetation type increased from 1500 to 3264 mg N•m−2 as a result of clearing. Soil temperature declined with advancing succession and generally increased as a consequence of clearing. However, these changes were not as closely correlated with N mineralization as were the changes in substrate chemistry encountered across this successional sequence.


REPORTS ◽  
2021 ◽  
pp. 53-56
Author(s):  
Gulzinat Seribekkyzy ◽  
Bolat Esimov

This article discusses the species composition of earthworms in the soils of the beyond Ile Alatau region. The role of earthworms in the soil is quite large. First of all, it is worth noting their loosening and structuring activities. During the movement process, these soil invertebrates mix a huge number of small fractions of soil. The loosening activity promotes moisture and sufficient oxygen. The most important is the destructive activity and enrichment of soils with active substances, as enzymes. The study of lumbricides began from the time of Charles Darwin, and is still of great importance the essence of such invertebrates in zoology. Scientific researchers had been carried out over two years (2018-2020) during the active vegetation of plants on the soils of the highest point of the beyond Ile Alatau region - in the peak of Talgar. As a result of the conducted research, the following earthworm species from the Lumbricidae family were found: Octolasium lacteum, Eisenia foetida, Eisenia nordenskioldi, Nicodrilus caliginosus, Nicodrilus longus, Lumbricus rubellus, Lumbricus terrestris, Dendrobaena octaedra. The most common species are Lumbricus rubellus and Nicodrilus caliginosus, and the rest are less common. In the seasonal dynamics of earthworm numbers, two peaks of activity were observed - in early June and at the end of August.


1989 ◽  
Vol 69 (3) ◽  
pp. 705-709 ◽  
Author(s):  
S. BRAIS ◽  
P. BHÉREUR ◽  
D. GAGNON ◽  
D. CODERRE

Impacts of silvicultural practices on soil structure were evaluated in hardwood plantations. On two different sites, four treatments (mechanical weed control, herbicide weed control, seeding of nitrogen-fixing companion species and a control) were undertaken, with and without earthworm introduction, according to a complete randomized block design. Treatments had significant effects on the water stability of soil aggregates, macroporosity and bulk density. Earthworm introduction significantly increased macroporosity in control plots while decreasing it in the three other treatments. Key words: Soil structure, silvicultural practices, earthworm, Lumbricus terrestris


1998 ◽  
Vol 76 (1) ◽  
pp. 104-109 ◽  
Author(s):  
Kevin R Butt ◽  
Visa Nuutinen

Mature virgin individuals of the simultaneously hermaphroditic earthworm Lumbricus terrestris Linné were housed in small groups and allowed access to each other under continuous video observation. After copulation, earthworms were isolated and thereafter their mass and the number of cocoons they produced were recorded monthly. Mated individuals produced cocoons for up to 12 months after the mating, while unmated individuals produced no cocoons. Hatchability of cocoons ranged from 76 to 62% over the 5 months following the mating, but decreased to 11% in the sixth month. Cocoons produced beyond that period failed to hatch. The median period of viable cocoon production was 3 months. Monthly cocoon production peaked 2-3 months after the mating, when 2-3 (1-2 viable) cocoons per individual were produced. Median total production of viable cocoons was 5 per individual (range 0-21). There was no discernible relationship between cocoon production and length of copulation, individual longevity, or individual mass at mating. Both partners usually contributed to the production of viable cocoons, but within mating pairs there was a median difference of 4 cocoons. Median survival time after the experimental mating period was 9 and 11 months for mated and unmated earthworms, respectively.


1990 ◽  
Vol 20 (3) ◽  
pp. 259-266 ◽  
Author(s):  
Jeremy S. Fried ◽  
James R. Boyle ◽  
John C. Tappeiner II ◽  
Kermit Cromack Jr.

Soil chemical and physical properties, forest floor weights, nutrient content and turnover rates, and litter fall weights and nutrient content under bigleaf maple (Acermacrophyllum Pursh) and Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco var. menziesii) were compared on five sites on the eastern margin of the Oregon Coast Range. Litter fall weight and nutrient content were significantly greater under maple on every site for every macronutrient and for most micronutrients. Forest floor biomass and nutrient content were extremely variable, much more so than litter fall, and there were no consistent differences between the two species. However, turnover rates for forest floor biomass and nutrients were significantly faster under maple for every nutrient at every site. Bulk density of mineral soil was also highly variable with significant differences at only two sites. Soil under maple was consistently higher in nitrogen, and less consistently, in potassium. There were no consistent trends in amounts of calcium, magnesium, or phosphorus. Soil organic carbon content under maple was significantly greater than under Douglas-fir on four of five sites. These differences may result from the more rapid turnover of forest floors under maple trees.


1997 ◽  
Vol 77 (4) ◽  
pp. 703-711 ◽  
Author(s):  
Aynslie E. Ogden ◽  
Margaret G. Schmidt

In some low-elevation coastal British Columbia forests, canopy gaps can be occupied by the hardwood tree species, vine maple (Acer circinatum). The objective of this study was to determine how vine maple gaps influence litterfall, litter decomposition, and forest floor and mineral soil properties. Measurements were made on six vine maple gaps paired with six conifer canopy plots. Vine maple gaps had significantly less conifer litterfall during the autumn, higher pH, and higher concentrations of Ca, Mg and K in the forest floor, thinner forest floors, and a weak tendency for lower C/N ratios, higher pH values and higher total N concentrations in the surface mineral soil. Vine maple litter was found to decompose significantly faster than conifer litter and to have higher concentrations of N, P, Ca, Mg, K, Fe and Zn. Decomposition rates of vine maple litter and of conifer litter did not differ significantly between vine maple gap and conifer canopy plots. Larger vine maple clones had significantly thicker forest floors with higher concentrations of Ca, and higher N concentrations and lower C/N ratios in the surface mineral soil than gaps with smaller vine maple clones. The results indicate that vine maple gaps may improve the nutritional status of the sites that they occupy within conifer forests. Key words: Litterfall, litter decomposition, soil-plant interactions, vine maple, canopy openings, canopy gaps


Sign in / Sign up

Export Citation Format

Share Document