Disturbance history affects lightning fire initiation in the mixedwood boreal forest: Observations and simulations

The effects of partial and clear-cut harvesting on abundance and community composition of forest floor microarthropods and oribatid mites were investigated in conifer and deciduous stands of the mixedwood boreal forest. Soil samples from clearcuts, strip-cut corridors in a partial cut, green-tree retention patches in a partial cut, and uncut control sites were collected 2.5 years after harvest and microarthropods were extracted, enumerated, and identified. Densities of microarthropod suborders were lower in the strip-cut corridors of the deciduous stands and significantly lower in the suborder Oribatida (oribatid mites). Changes in microarthropod community composition, decreased relative abundance of prostigmatid mites, and increased relative abundance of mesostigmatid mites were observed in corridor and clear-cut treatments. Lowered abundances and changes in community composition are likely due to compaction of the forest floor during harvesting. Selected oribatid mite species showed significantly lower abundances in clearcuts than in uncut sites, but diversity indices for oribatid mites were generally not significantly different between uncut sites and clearcuts. Changes in oribatid mite communities following harvesting were thus more quantitative (absolute abundance) than qualitative (diversity, composition), and as a result, use of oribatid mites as biological indicators of disturbance is limited because of the lack of changes in species composition.

Download Full-text

Temporal variation in quaking aspen (Populus tremuloides) genetic and clonal structures in the mixedwood boreal forest of eastern Canada

Ecoscience ◽

10.2980/i1195-6860-12-1-82.1 ◽

2005 ◽

Vol 12 (1) ◽

pp. 82-91 ◽

Cited By ~ 6

Author(s):

Marie-Claire Namroud ◽

Francine Tremblay ◽

Yves Bergeron

Keyword(s):

Boreal Forest ◽

Temporal Variation ◽

Populus Tremuloides ◽

Quaking Aspen ◽

Eastern Canada ◽

Mixedwood Boreal Forest

Download Full-text

Estimates of catchment area of pitfall traps for carabids

ARPHA Conference Abstracts ◽

10.3897/aca.2.e38518 ◽

2019 ◽

Vol 2 ◽

Cited By ~ 1

Author(s):

Colin Bergeron

Keyword(s):

Boreal Forest ◽

Catchment Area ◽

Linear Models ◽

Deciduous Forest ◽

Species Level ◽

Pitfall Traps ◽

Circular Field ◽

C 30 ◽

Mixedwood Boreal Forest ◽

The Relationship

Relationships between beetle abundance in the field and data collected from pitfall traps has generated much interest from several generations of carabidologists. Despite the argument and controversy about this relationship, pitfall data remain the main source of knowledge about carabid populations and assemblages in nature. In order to estimate the relationship between pitfall catches of carabids and catchment area in a homogenous deciduous forest, we constructed circular field enclosures of three sizes (radii: 2.5m, 5m and 10m) and sampled carabids using single pitfall traps located in the centre of each enclosure over 3 seasons (2014-2016). We found that overall beetle catches increased linearly with enclosure area during all three years, and the linear models were nearly identical for the two years (2014 and 2016) in which the data were comparable. We then extrapolated the relationship to predict the catchment area using unenclosed traps run simultaneously. For data from both 2014 and 2016, the catchment area for the assemblage is predicted to be 620-640 m2, representing a radius of c. 14.3 m. Interestingly, this value is consistent with the published inter-trap distance required for independence of trap captures at the same site. Unfortunately, but as expected, calibration of pitfall data at the species level is challenging because the best linear model fits vary considerably among species. Trap catchment area also increased during breeding season. Clearly, pitfall traps need to be set at least c. 30 meters apart to ensure independence of samples in mixedwood boreal forest.

Download Full-text