Effect of habitat type and pitfall trap installation on captures of epigaeic arthropod assemblages in the boreal forest

2013 ◽  
Vol 145 (5) ◽  
pp. 547-565 ◽  
Author(s):  
J.A. Colin Bergeron ◽  
John R. Spence ◽  
W. Jan A. Volney ◽  
Jaime Pinzon ◽  
Dustin J. Hartley

AbstractIt is unrealistic to achieve high-resolution biodiversity inventories required to support local conservation strategies over large areas; however, benchmark associations between arthropods and ecosystem classification can support landscape scale biomonitoring. We investigated habitat associations of ground-dwelling spiders (Araneae), staphylinid beetles (Coleoptera: Staphylinidae), and carabid beetles (Coleoptera: Carabidae) in three forest ecosystems in northwestern Alberta, Canada and also studied the effect of variation in depth of pitfall trap installation on catch. Composition and diversity of all three taxa were correlated with the ecosystem classification map, and 20 species were strong indicators of particular habitats. The black spruce (Picea mariana(Miller) Britton, Sterns, and Poggenburg; Pinaceae) bog supported fewer species and individuals of beetles but this trend was not observed for spiders because of natural history traits associated with their performance in this environment. Pitfall trapping biases were constant among habitats enabling proper comparison of ground-dwelling invertebrate assemblages. Three species of beetles (Agonum retractumLeConte (Coleoptera: Carabidae),Pterostichus brevicornis(Kirby) (Coleoptera: Carabidae), andQuedius veloxSmetana (Coleoptera: Staphylinidae)) were disproportionally active beneath the soil surface, as catches were greater in pitfall traps with the lip situated 15–25 cm below the soil surface. Thus, even highly standardised trap placement will influence the concept of biodiversity achieved through pitfall trapping, because some target organisms are disproportionately active in subterranean zones.

2003 ◽  
Vol 14 (1) ◽  
Author(s):  
Matti Koivula ◽  
Johan Kotze ◽  
Laura Hiisivuori ◽  
Hannu Rita

Apart from experimental design, the selection of pitfall trap size, collecting fluid and habitat type sampled may also influence the capture efficiency of the method. We combined three field studies from two very different geographic areas, in which the efficiency of pitfall traps, using carabid beetles (Coleoptera: Carabidae), is evaluated. First, we showed that ethylene-glycol is a more efficient collecting fluid compared to commercial anti-freeze, paraffin and salt water in collecting beetles in a forest patch in South Africa. Second, we showed that larger traps (90 mm mouth diameter) are more efficient in collecting carabids than small traps (65 mm) in a meadow in Finland. We also showed that for these large traps, commercial vinegar was a better collecting fluid than propylene-glycol, but that for small traps, propylene-glycol was superior to vinegar in collecting carabids. Finally, we showed that the trappability of Pterostichus oblongopunctatus and Carabus hortensis differed in enclosures placed into two different habitat types (a forest and a clear-cut in Finland), while trappability did not differ significantly for two other species (Calathus micropterus and Pterostichus niger) in these habitat types. However, for the two Pterostichus species studied, the catches in traps placed in the centre of the enclosures were slightly higher in the clear-cut, compared to the forest, and catches were higher in enclosures with rich field-layer vegetation, compared to enclosures with poor vegetation. The three studies re-emphasise the uncertainties of using pitfall traps in ecological studies. However, with careful planning and standardisation to help avoid erroneous interpretations, pitfall trapping is an invaluable method for the field ecologist.


1995 ◽  
Vol 6 (2-3) ◽  
pp. 65-77 ◽  
Author(s):  
Johan Andersen

A comparison was made betweeen the "open" pitfall trap method and quadrat sample method in microhabitats on river banks. The latter method was found to give reliable estimates of the absolute abundance of carabid beetle species. In pitfall traps individuals of the carabid beetle Bembidion schuppelii were over-represented in a sub-optimal microhabitat compared with in optimal ones. The niche-overlap between this species and B. bipunctatum was 0.19 in quadrat samples and 0.59 in pitfall traps. There was no correlation between the relative abundance of individuals of species in quadrat samples and in pitfall traps. Individuals of larger carabid species were highly over-represented compared to smaller ones in pitfall traps, an effect that was independent of diurnal rhythm and life cycle category. Biomass of larger carabid species was also overestimated in pitfall traps compared to that of smaller ones. Imagines were more efficiently captured in pitfall traps than larvae. Pitfall traps had a higher number of species than quadrat samples in all investigated sites. In four of five cases the Shannon-Wiener index gave higher species diversity in pitfall traps than in quadrat samples. It is concluded that the "open" pitfall trap method is inappropriate to study dominance ratio, the ecological role of species and perhaps the species diversity within communities. The general insight into the community structure of carabid beetles may therefore be very biased.


2012 ◽  
Vol 64 (2) ◽  
pp. 721-732 ◽  
Author(s):  
I.H. Tuf ◽  
P. Dedek ◽  
M. Veselý

The influence of season, ground temperature and habitat on diurnal epigeic activity of ground beetles (Coleoptera: Carabidae) in floodplain forest and neighboring clear-cut area was studied in late spring and early autumn by pitfall trapping. Among the material collected were 35 species of ground beetles. We recorded a significant influence of daytime factors on epigeic activity in 16 species. The epigeic activity of 13 species was co-affected by the temperature of the soil surface. The activity of some species differed, depending on season and locality.


2006 ◽  
Vol 17 (3) ◽  
Author(s):  
Angela Taboada ◽  
Johan Kotze ◽  
José Salgado ◽  
Reyes Tárrega

We investigated the responses of carabid beetles to habitat type at the local scale in traditionally managed “dehesa” ecosystems in NW Spain. The beetles were sampled from two habitat types (central grassland and surrounding forested zone) of five “dehesa” ecosystems, from May to October 2004. Atotal of 4,374 carabid individuals and 55 species were captured using pitfall trapping. Most of the species were collected from both habitat types, probably due to open spaces created between old-growth trees in the forested zone. Differences in carabid assemblage composition were found mainly due to Harpalus species characteristic from the central grassland and a few forest specialist species exclusively found in the forested zone. The maintenance of the “dehesa” structure may be of importance for carabid species adapted to the variety of habitats created, and requires the continuation of traditional management practices.


1994 ◽  
Vol 70 (2) ◽  
pp. 151-158 ◽  
Author(s):  
R. L. Fleming ◽  
D. S. Mossa

A series of spot seeding experiments was set out on coarse-textured upland sites in northwestern Ontario to investigate how black spruce (Picea mariana [Mill.] B.S.P.) seedling establishment and growth could be improved by site selection and seedbed preparation. Virtually all germination occurred within the first growing season. Annual seedling mortality rates were greatest during the first year, then declined steadily and stabilized at low levels (<10%) after the third year. The highest fifth-year establishment ratios (seedlings/viable seed sown) were found on seedbeds derived from materials near the mineral soil/humus interface. On wetter sites (i.e., higher Soil Moisture Regimes) the best seedbeds occurred closer to the soil surface. Mean fifth year establishment ratios for the best seedbeds were 0.032 on moderately fresh to fresh sites, 0.146 on very fresh to moderately moist sites, and 0.082 on moist to very moist sites. On adjacent lowland sites, slow-growing, compact Sphagnum mosses had a mean establishment ratio of 0.179. Mean fifth-year seedling heights on upland sites ranged from 12 to 14 cm, and were not strongly correlated with site or seedbed type. Key words: direct seeding, black spruce, seedbed, seedling establishment, site type and germination


1984 ◽  
Vol 116 (2) ◽  
pp. 165-171 ◽  
Author(s):  
N. J. Holliday ◽  
E. A. C. Hagley

AbstractThe effects on carabids of natural, fescue, and rye sod types and of tillage were investigated in a pest management apple orchard. Carabids were sampled before and after the treatments by pitfall trapping and by two types of soil sampling. There were no significant effects of sod type on pitfall trap catches; however the abundance of all common species in soil samples was significantly affected by sod types. Usually in soil samples carabids were most abundant in natural sod and least abundant in tilled plots; numbers were intermediate in fescue and rye. Sod type did not affect structure or diversity of the carabid fauna.


2016 ◽  
Vol 37 (3) ◽  
pp. 325-330 ◽  
Author(s):  
João Carlos Campos ◽  
Fernando Martínez-Freiría ◽  
Fábio Vieira Sousa ◽  
Frederico Santarém ◽  
José Carlos Brito

The West African crocodile (Crocodylus suchus) is an emblematic species from the Sahara-Sahel with scarce knowledge on distribution and conservation status. This study updated the knowledge on distribution, occupied habitats, population size, and factors that threaten C. suchus and its habitats in Mauritania. Five field expeditions to Mauritania (2011-2016), allowed the detection of 26 new localities, increasing by 27% the current number of all known locations (adding up to ). In most localities less than five individuals were observed, and in all visiting sites the number of observed individuals ranged from one to 23. Eleven threat factors were identified, being droughts and temperature extremes (100% localities affected) and water abstraction for domestic use and nomadic grazing (94%) the most frequent. These findings suggest that crocodiles are apparently vulnerable in Mauritania and that future local conservation strategies are needed to assure the continuity of its fragile populations and preserve their habitats.


2020 ◽  
Author(s):  
Pavel Saska ◽  
David Makowski ◽  
David Bohan ◽  
Wopke van der Werf

AbstractCarabid beetles (Coleoptera: Carabidae) provide important ecological services and are frequently used as a bio-indicator in monitoring environmental quality. The abundance and diversity of carabids is usually determined using pitfall trapping, but trap catches are difficult to compare between studies due to variation in trapping effort. The standardization of the catch for trapping effort has not been previously addressed in a global analysis of studies in the literature.The aims of this study are (i) to define a method for estimating the effect of trapping effort on the size of the pitfall catch, and (ii) to explore factors related to study designs, sampling method, study origin, and level of data aggregation to determine how these factors affect the catch per unit effort in pitfall trapping.We conducted a meta-analysis on the activity-density and diversity of carabids across studies, based on published data from Europe and North-America to analyse whether standardization of catch measurements might be possible. Data were extracted from 104 publications, spanning a period of 42 years.The total catch was proportional to the number of trap days, and ranged from 0.19-9.53 beetles/(trap day) across studies (95% range), with a mean of 1.33 beetles/(trap day). The number of species was allometrically related to the trapping effort defined as the product of the number of traps, their perimeter and the time of exposure in the field, and characterized by a power exponent of 0.25. Species richness ranged across studies from 2.30-13.18 species/(m day)0.25 (95% range) with a mean of 7.15 species/(m day)0.25. The size of the catch and the number of species were higher in crops with narrow as compared to wide rows. There was no significant change in abundance or diversity of carabids in arable land over the 42 years covered. We also found that increasing trapping effort may not yield more accurate results.The results show that it is possible to standardize activity-density-based catches and species diversity for trapping effort across studies using a power transformation, allowing meta-analysis of such data, e.g. to elucidate factors affecting abundance and diversity of the focal taxa.


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