Fine woody debris is important for species richness on logs in managed boreal spruce forests of northern Sweden

1999 ◽  
Vol 29 (8) ◽  
pp. 1295-1299 ◽  
Author(s):  
Nicholas Kruys ◽  
Bengt Gunnar Jonsson

Species richness of wood-inhabiting cryptogams was compared on fine woody debris (FWD; diameter 5-9 cm) and coarse woody debris (CWD; diameter [Formula: see text]10 cm) logs of Picea abies (L.) Karst. Data were collected from managed boreal forests of northern Sweden. Species richness was higher on CWD than FWD when equal numbers of logs were compared. When equal surface areas were compared, species richness on FWD and CWD did not differ. When equal volumes of CWD and FWD were compared, FWD had more species. This was an effect of surface area and log quantity, as a certain volume of FWD was composed of more logs and had greater surface area than the same volume of CWD. We varied woody debris volume and proportion of FWD in a simulation model of species richness on logs. At low volumes of woody debris, species richness increased with the proportion of FWD. At higher log volumes, species richness increased with the proportion of CWD. In managed forests where there are small amounts of woody debris, FWD is important for the total species richness on logs and should not be neglected despite the fact that species richness is generally positively correlated with log diameter.

2008 ◽  
Vol 38 (7) ◽  
pp. 1807-1816 ◽  
Author(s):  
Björn Nordén ◽  
Frank Götmark ◽  
Martin Ryberg ◽  
Heidi Paltto ◽  
Johan Allmér

Partial cutting is increasingly applied in European temperate oak-dominated forests for biofuel harvesting, and to counteract succession in protected stands. Effects on biodiversity of these measures need to be carefully evaluated, and species-rich but neglected taxa such as fungi should be considered. We studied the effects of partial cutting on fungal fruiting bodies on woody debris. In 21 closed canopy forests rich in large oaks in Sweden, on average 25%–30% of the basal area was cut. Fruiting bodies were counted and some were collected in treated and control plots before and after treatment. We found 334 basidiomycete and 47 ascomycete species. Species richness of basidiomycetes declined significantly more in treated plots (on average 26%) than in control plots (on average 13%) between seasons. Species richness of ascomycetes increased by 17% in control plots and decreased by 2% in treated plots. Total species richness was significantly reduced on fine woody debris (1–10 cm in diameter), but not on coarse woody debris (>10 cm). Overall species composition did not change significantly as a result of partial cutting, but red-listed species tended to decrease more in treated plots. We suggest that approximately 30% of the stands should not be thinned, and dead stems and fallen branches should not be removed, to favor saproxylic fungi and their associated fauna.


2012 ◽  
Vol 144 (3) ◽  
pp. 491-507 ◽  
Author(s):  
R.J. Higgins ◽  
B.S. Lindgren

AbstractAnts (Hymenoptera: Formicidae) are ubiquitous and of considerable ecological interest, yet poorly studied in Canada. Given their natural history attributes and relatively low density and diversity in cool boreal forests, there is a need to evaluate the applicability of commonly used approaches to sampling and analysis. We examined the relative utility of two pitfall trap designs, mini-Winkler litter extractions, and colony versus forager sampling for ecological studies. First, we found that Laurent (conventional) and Nordlander (modified to exclude larger nontarget organisms) pitfall traps were equally efficacious for estimating total species richness. Second, pitfall trapping yielded marginally higher total species richness than mini-Winkler litter sampling, by the incidence-based estimator (Chao2). Third, two studies considering the relationship between captures of individual ants in pitfall traps and identified ant colonies argued for caution in how pitfall captures are interpreted. In the first study, Nordlander traps placed in a grid surrounding nests ofFormica obscuripesForel revealed unique and highly patchy captures of individuals, with no patterns relating to proximity to the nest. In the second study, abundance estimates to compare ant assemblage structure in a simple grassland ecosystem by pitfall trapping (relative) and area-based hand sampling (absolute) for colonies, revealed that relative sampling does not reflect the absolute ant assemblage structure. Our results support, equivocally, the use of pitfall traps (Nordlander) over mini-Winklers in the cool moist forests of west-central British Columbia, but individual specimen counts should not be used when analysing the data.


2007 ◽  
Vol 50 (6) ◽  
pp. 1033-1042 ◽  
Author(s):  
Yzel Rondon Súarez ◽  
Sabrina Bigatão Valério ◽  
Karina Keyla Tondado ◽  
Alexandro Cezar Florentino ◽  
Thiago Rota Alves Felipe ◽  
...  

The influence of spatial, temporal and environmental factors on fish species diversity in headwater streams in Paraguay and Paraná basins, Brazil was examined. A total of 4,605 individuals were sampled, distributed in 60 species. The sampled streams in Paraná basin presented a larger total species richness (42) than Paraguay streams (40). However the estimated richness was larger in Paraguay basin (53) than Paraná streams (50). The streams of Paraná basin had a greater mean species richness and evenness, while more individuals per sample were found in the Paraguay basin. Difference between the sub-basins were found in the Paraguay basin, while for the basin of Paraná, richness and evenness vary significantly between the sub-basins, but the number of individuals varied seasonally. The most important environmental factors to species diversity and abundance were altitude, water temperature, stream width and stream depth for both the basins.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tanya A. Petruff ◽  
Joseph R. McMillan ◽  
John J. Shepard ◽  
Theodore G. Andreadis ◽  
Philip M. Armstrong

Abstract Historical declines in multiple insect taxa have been documented across the globe in relation to landscape-level changes in land use and climate. However, declines have either not been universally observed in all regions or examined for all species. Because mosquitoes are insects of public health importance, we analyzed a longitudinal mosquito surveillance data set from Connecticut (CT), United States (U.S.) from 2001 to 2019 to identify changes in mosquito community composition over time. We first analyzed annual site-level collections and metrics of mosquito community composition with generalized linear/additive mixed effects models; we also examined annual species-level collections using the same tools. We then examined correlations between statewide collections and weather variables as well as site-level collections and land cover classifications. We found evidence that the average trap night collection of mosquitoes has increased by ~ 60% and statewide species richness has increased by ~ 10% since 2001. Total species richness was highest in the southern portion of CT, likely due to the northward range expansion of multiple species within the Aedes, Anopheles, Culex, and Psorophora genera. How the expansion of mosquito populations in the northeast U.S. will alter mosquito-borne pathogen transmission in the region will require further investigation.


2009 ◽  
Vol 39 (11) ◽  
pp. 2100-2108 ◽  
Author(s):  
Patti Newell ◽  
Sammy King

Partial cutting techniques are increasingly advocated and used to create habitat for priority wildlife. However, partial cutting may or may not benefit species dependent on deadwood; harvesting can supplement coarse woody debris in the form of logging slash, but standing dead trees may be targeted for removal. We sampled cerambycid beetles during the spring and summer of 2006 and 2007 with canopy malaise traps in 1- and 2-year-old partial cut and uncut bottomland hardwood forests of Louisiana. We captured a total of 4195 cerambycid beetles representing 65 species. Relative abundance was higher in recent partial cuts than in uncut controls and with more dead trees in a plot. Total species richness and species composition were not different between treatments. The results suggest partial cuts with logging slash left on site increase the abundance of cerambycid beetles in the first few years after partial cutting and that both partial cuts and uncut forest should be included in the bottomland hardwood forest landscape.


2007 ◽  
Vol 144 (3) ◽  
pp. 465-486 ◽  
Author(s):  
CHRISTOPHER J. CLEAL

The South Wales Coalfield has the most complete Westphalian macrofloral record anywhere on the Variscan Foreland or adjacent basins, with 135 biodiversity-meaningful morphospecies having been recognized. All of the standard macrofloral biozones of the Westphalian Stage have been recognized, although a detailed comparison with the Central Pennines Coalfields has indicated some discrepancies in the relative positions of the biozonal boundaries. Total Species Richness progressively increases through the Langsettian Substage, and then remains relatively stable through most of the Duckmantian and Bolsovian substages. There is a distinct reduction in Total Species Richness towards the top of the Bolsovian Substage, but this partially recovers in the middle Asturian Substage with the appearance of a range of marattialean ferns, and medullosalean and callistophytaleans pteridosperms. There is no evidence of any significant drop in Total Species Richness towards the top of the succession, indicating that conditions at this time were relatively stable. The change from coastal floodplain to alluvial braidplain conditions in middle Bolsovian times correlates with a marked increase in the proportion of medullosalean remains being preserved in the adpression record, reflecting an expansion of the clastic-substrate habitats.


2019 ◽  
Vol 88 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Bernhard A. Huber ◽  
Anne Chao

Ratio-like approaches for estimating global species richness have been criticised for their unjustified extrapolation from regional to global patterns. Here we explore the use of cumulative percentages of ‘new’ (i.e., not formally described) species over large geographic areas (‘megatransects’) as a means to overcome this problem. In addition, we take into account undetected species and illustrate these combined methods by applying them to a family of spiders (Pholcidae) that currently contains some 1,700 described species. The raw global cumulative percentage of new species (‘new’ as of the end of 2008, when 1,001 species were formally described) is 75.1%, and is relatively constant across large biogeographic regions. Undetected species are estimated using the Chao2 estimator based on species incidence data (date by species and locality by species matrices). The estimated percentage of new species based on the date by species matrices is 76.0% with an estimated standard error (s.e.) of 2.6%. This leads to an estimated global species richness of about 4,200 with a 95% confidence interval of (3,300, 5,000). The corresponding values based on locality by species matrices are 84.2% (s.e. 3.0%) and 6,300 with a 95% confidence interval of (4,000, 8,600). Our results suggest that the currently known 1,700 species of Pholcidae may represent no more than about 25–40% of the total species richness. The impact of further biasing factors like geography, species size and distribution, cryptic species, and model assumptions needs to be explored.


1999 ◽  
Vol 29 (2) ◽  
pp. 178-186 ◽  
Author(s):  
Nicholas Kruys ◽  
Clas Fries ◽  
Bengt Gunnar Jonsson ◽  
Tomas Lämås ◽  
Göran Ståhl

We surveyed the quantity and quality of dead Norway spruce (Picea abies (L.) Karst.) trees and wood-inhabiting cryptogams in a managed boreal forest landscape in northern Sweden. Size and decay of dead trees was related to substrate utilization by wood-inhabiting species. Coarse woody debris (CWD) was surveyed along 34 strip transects. CWD and wood-inhabiting cryptogams were surveyed in eight circular plots at each site. A total of 6195 spruce CWD units occurred along strip transects and 809 spruce CWD units in circular plots. On average 2.2 m3/ha spruce CWD was found on the plots. The majority (63%) of the transect CWD units were <10 cm diameter and in early to intermediate decay stages. Sixty-eight wood-specific species of fungi, lichens, mosses, and hepatics occurred on the plots. Of these, 13 occurred on [Formula: see text]5% of the 809 CWD units surveyed for wood-inhabiting species. Eight species occur on the Swedish red lists, indicating that such species are indeed uncommon in managed forests. Red-listed species showed strong preferences for large diameter CWD and CWD in late decay stages, i.e., substrates that are poorly represented in managed forests. Frequently occurring species, however, showed utilization patterns that correspond with the distribution of the substrate types.


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