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Pitfall Traps (pitfall + trap)

Distribution by Scientific Domains

Life Sciences	76%
Earth and Environmental Science	15%

Distribution within Life Sciences

Ecology & Organismal Biology	39%
Entomology	32%
Conservation Science	9%
4 Other Subdomains	20%

Selected Abstracts

Smaller and more numerous harvesting gaps emulate natural forest disturbances: a biodiversity test case using rove beetles (Coleoptera, Staphylinidae)

DIVERSITY AND DISTRIBUTIONS, Issue 6 2008
Jan Klimaszewski
ABSTRACT Aim To evaluate changes in the abundance, species richness and community composition of rove beetles (Coleoptera, Staphylinidae) in response to three configurations of experimental gap cuts and to the effects of ground scarification in early succession yellow birch-dominated boreal forest. In each experimental treatment, total forest removed was held constant (35% removal by partial cutting with a concomitant decrease in gap size) but the total number of gaps was increased (two, four and eight gaps, respectively), resulting in an experimental increase in the total amount of ,edge' within each stand. Location Early succession yellow birch-dominated forests, Quebec, Canada. Methods Pitfall traps, ANOVA, MIXED procedure in sas®, post hoc Tukey's adjustment, rarefaction estimates, sum-of-squares and distance-based multivariate regression trees (ssMRT, dbMRT). Results Estimates of species richness using rarefaction were highest in clearcut and two-gap treatments, decreased in smaller and more numerous gaps and were significantly higher in scarified areas than in unscarified areas. ANOVA indicated a significant impact of harvesting on the overall standardized catch. Post hoc Tukey's tests indicated that the total catch of all rove beetles was significantly higher in uncut forests than in the treated areas. Both sum-of-squares and distance-based multivariate regression trees indicated that community structure of rove beetles differed among treatments. Assemblages were grouped into (a) control plots, (b) four- and eight-gap treatments and (c) two-gap and clearcut treatments. Main conclusions Rove beetle composition responded significantly to increasing gap size. Composition among intermediate and small-sized gap treatments (four- and eight-gap treatments) was more similar to uncut control forests than were larger gap treatments (two-gap) and clearcuts. Effects of scarification were nested within the harvested treatments. When the total area of forest removed is held constant, smaller, more numerous gaps are more similar to uncut control stands than to larger gaps and falls more closely within the natural forest heterogeneity. [source]

Tillage affects the activity-density, absolute density, and feeding damage of the pea leaf weevil in spring pea

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 3 2010
Timothy D. Hatten
Abstract Conversion from conventional-tillage (CT) to no-tillage (NT) agriculture can affect pests and beneficial organisms in various ways. NT has been shown to reduce the relative abundance and feeding damage of pea leaf weevil (PLW), Sitona lineatus L. (Coleoptera: Curculionidae) in spring pea, especially during the early-season colonization period in the Palouse region of northwest Idaho. Pitfall traps were used to quantify tillage effects on activity-density of PLW in field experiments conducted during 2001 and 2002. As capture rate of pitfall traps for PLW might be influenced by effects of tillage treatment, two mark-recapture studies were employed to compare trapping rates in NT and CT spring pea during 2003. Also in 2003, direct sampling was used to estimate PLW densities during the colonization period, and to assess PLW feeding damage on pea. PLW activity-density was significantly lower in NT relative to CT during the early colonization period (May) of 2001 and 2002, and during the late colonization period (June) of 2002. Activity-density was not different between treatments during the early emergence (July) or late emergence (August) periods in either year of the study. Trap capture rates did not differ between tillage systems in the mark-recapture studies, suggesting that pitfall trapping provided unbiased estimates of PLW relative abundances. PLW absolute densities and feeding damage were significantly lower in NT than in CT. These results indicate that NT provides a pest suppression benefit in spring pea. [source]

Design of a time-sorting pitfall trap for surface-active arthropods

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2009
Sascha Buchholz
First page of article [source]

An Experimental Investigation of Landscape Resistance of Forest versus Old-Field Habitats to Emigrating Juvenile Amphibians

CONSERVATION BIOLOGY, Issue 5 2002
Betsie B. Rothermel
Larval amphibians,spotted salamander (Ambystoma maculatum), small-mouthed salamander (A. texanum), and American toad ( Bufo americanus ),were added to artificial pools in four dispersal arrays on forest edges. Each array consisted of a pool surrounded by a circular drift fence with pitfall traps and two 2.5 × 50 m enclosures (runs) extending into forest and old-field habitat. Juveniles captured at the circular fences were individually marked and released into either field or forest runs. We determined initial distance, initial rate, total distance, and net distance moved by juveniles in the field versus forest from recaptures in the runs. We also conducted 24-hour dehydration trials to compare the rates of evaporative water loss by spotted and small-mouthed salamanders in field and forest. Initial orientation of spotted salamanders and toads was significantly biased toward forest. Orientation of small-mouthed salamanders did not differ significantly from random expectations. The avoidance of open-canopy habitat by juvenile American toads in particular indicates that predictions of dispersal behavior based on adult habitat use may be misleading. Spotted salamanders moved almost four times farther and toads more than three times farther into the forest than into the field, and recapture rates of both species were much lower in the field. We attribute the lower recapture rates and shorter distances moved in the field to higher mortality due to desiccation or an abundance of predators. Juvenile spotted and small-mouthed salamanders experienced greater evaporative water loss in the field. Our data on movement behavior and dehydration rates suggest that old-field habitats offer greater landscape resistance to dispersing juveniles of some species. Thus, forest fragmentation is likely to reduce dispersal rates between local populations of these three species, with potentially negative consequences for population persistence in altered landscapes. Resumen: Utilizamos un enfoque experimental para investigar los efectos de la composición del paisaje sobre el éxito inicial de dispersión de anfibios juveniles. Colcamos larvas de anfibios (salamandras manchadas [Ambystoma maculatum] y A. texanum y sapo americano [Bufo americanus] ) en estanques artificiales en cuatro secuencias de dispersión en bordes de bosque. Cada secuencia consistió de un estanque rodeado por un cerco circular con trampas de fosa y dos encierros (corridas) de 2.5 × 50 m que se extendían hacia el hábitat de bosque y de campo viejo. Los juveniles capturados en los cercos circulares fueron marcados individualmente y liberados en las corridas de bosque o de campo. A partir de recapturas en las corridas, determinamos la distancia inicial, la tasa inicial, las distancia total y la distancia neta recorrida por juveniles en el campo versus el bosque. También realizamos pruebas de deshidratación de 24 horas para comparar las tasas de pérdida de agua por evaporación en salamandras en el campo y el bosque. La orientación inicial de Ambystoma maculatum y Bufo americanus estuvo significativamente sesgada hacia el bosque. La orientación inicial de A. texanum no fue significativamente diferente de las expectativas aleatorias. La evasión del hábitat abierto en particular por juveniles de sapo americano indica que las predicciones del comportamiento de dispersión basadas en el uso del hábitat por adultos pueden llevar a conclusiones erróneas. Las salamandras manchadas se movieron cuatro veces mas lejos y los sapos más de tres veces más lejos dentro del bosque que dentro del campo, y las tasas de recaptura de ambas especies fueron mucho menores en el campo. Atribuimos las bajas tasas de recaptura y las distancias menores a la mayor mortalidad debido a la desecación o a la abundancia de depredadores. Los juveniles de las dos especies de salamandras experimentaron mayor pérdida de agua por evaporación en los campos. Nuestros datos del comportamiento de movimiento y las tasas de deshidratación sugieren que los hábitats de campo viejo ofrecen mayor resistencia de paisaje para los juveniles dispersantes de algunas especies. Por tanto, es probable que la fragmentación de bosques reduce las tasas de dispersión entre poblaciones locales de estas tres especies, con consecuencias potencialmente negativas para la persistencia de la población en paisajes alterados. [source]

The effects of green tree retention and subsequent prescribed burning on ground beetles (Coleoptera: Carabidae) in boreal pine-dominated forests

ECOGRAPHY, Issue 5 2006
Petri Martikainen
We studied how two methods to promote biodiversity in managed forests, i.e. green tree retention and prescribed fire, affect the assemblages of carabid beetles. Our experiment consisted of 24 study sites, each 3,5 ha in size, which had been prepared according to factorial design. Each of the eight treatment combinations determined by the two factors explored , tree retention level (0, 10, 50 m3/ha,1 and uncut controls) and prescribed use of fire (yes/no) , was replicated three times. We sampled carabids using pitfall traps one year after the treatments. Significantly more individuals were caught in most of the burned sites, but this difference was partially reflective of the trap-catches of Pterostichus adstrictus. The fire did not increase no. of P. adstrictus in the uncut sites as much as in the other sites. Species richness was significantly affected by both factors, being higher in the burned than in the unburned sites and in the harvested than in the unharvested sites. Many species were concentrated in the groups of retention trees in the burned sites, but only a few were in the unburned sites. The species turnover was greater in the burned than in the unburned sites, as indicated by the NMDS ordinations. Greater numbers of smaller sized species and proportion of brachypterous species were present in the burned sites. Fire-favored species, and also the majority of other species that prefer open habitats were more abundantly caught in the burned sites than in the unburned sites. Dead wood or logging waste around the traps did not correlate with the occurrence of species. We conclude that carabids are well adapted to disturbances, and that frequent use of prescribed fire is essential for the maintenance of natural assemblages of carabid beetles in the boreal forest. Small retention tree groups can not maintain assemblages of uncut forest, but they can be important by providing food, shelter and breeding sites for many species, particularly in the burned sites. [source]

Post-fire recovery of ant communities in Submediterranean Pinus nigra forests

ECOGRAPHY, Issue 2 2006
Anselm Rodrigo
This study analyzes the variations in the structure and composition of ant communities in burned Pinus nigra forests in central Catalonia (NE Spain). Pinus nigra forests do not recover after fire, changing to shrublands and oak coppices. For this reason, we suggest that ant communities of burned P. nigra forests will change after fire, because the post-fire scenario, in particular with the increase of open areas, is different to the unburned one, and more favourable for some species than for others. In four locations previously occupied by P. nigra forests where different fires occurred 1, 5, 13 and 19 yr before the sampling, we sampled the structure and composition of ant communities with pitfall traps, tree traps and net sweeping in unburned plots and in plots affected by canopy and understory fire. The results obtained suggest that canopy and understory fire had little effect on the structure of ant communities. Thus, many variables concerning ant communities were not modified either by fire type (understory or canopy fire) or by time since fire. However, a number of particular species were affected, either positively or negatively, by canopy fire: three species characteristic of forest habitats decreased after fire, while eight species characteristic of open habitats increased in areas affected by canopy fire, especially in the first few years after fire. These differences in ant community composition between burned and unburned plots imply that the maximum richness is achieved when there is a mixture of unburned forests and areas burned with canopy fire. Moreover, as canopy cover in P. nigra forests burned with canopy fire is not completed in the period of time studied, the presence of the species that are characteristic of burned areas remains along the chronosequence studied, while the species that disappear after fire do not recover in the period of time considered. Overall, the results obtained indicate that there is a persistent replacement of ant species in burned P. nigra forests, as is also the case with vegetation. [source]

Impact of reindeer grazing on ground-dwelling Carabidae and Curculionidae assemblages in Lapland

ECOGRAPHY, Issue 4 2003
Otso Suominen
Reindeer Rangifer tarandus L. grazing shapes forest vegetation, microclimate, and soil respiration in Lapland, especially due to grazing on lichens (Cladina). We studied how these changes and their magnitude affect ground-dwelling species of beetle families Carabidae (predators) and Curculionidae (herbivores), by using pitfall traps to collect invertebrates from pairs of grazed and ungrazed study plots over a wide range of site types. Changes in abundance, composition, richness and diversity of beetle assemblage were tested in relation to magnitude of the impacts on vegetation. The species compositions of Carabidae and Curculionidae differed between grazed and ungrazed plots in all sites. The relative difference between grazed and ungrazed plots in the number of individuals increased linearly with the impact of reindeer on vegetation cover. Carabid beetles, as a family, were more common in grazed plots in all sites. Curculionid beetles were more common in ungrazed plots in the birch dominated sites. This difference was mainly due to the species that feeds on deciduous leaves. In the pine dominated sites with high Cladina cover and more changes in ground vegetation, the number of curculionids feeding on conifers was higher in grazed plots. Species richness and diversity (H') of both families were higher in grazed plots. Of the total 27 species, 11 were found only in grazed plots, while not a single species was found only in ungrazed plots. The relative difference between plots in diversity and evennes (H'/H'max) had humped response to the difference in Cladina cover. The diversity values were greater in grazed plots at the intermediate levels of grazing impact, and only in sites with very low or extremely high Cladina cover difference was the diversity higher in ungrazed plots. The response of beetle diversity resembled the hypotheses suggested for the relationship between grazing and vegetation diversity: greatest positive effect at intermediate grazing intensity and negative effects at unproductive sites. [source]

Tillage affects the activity-density, absolute density, and feeding damage of the pea leaf weevil in spring pea

Capture efficiency of pitfall traps is highly affected by sampling interval

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2010
Jens Schirmel
First page of article [source]

External Features of the First Instar Larva of Damaster (Coptolabrus) jankowskii jankowskii (Coleoptera; Carabidae)

ENTOMOLOGICAL RESEARCH, Issue 2 2002
Jung Lark KIM
ABSTRACT Larval features of the carabid beetle, Damaster (Coptolabrus) jankowskii jankowskii (Oberthür) were investigated for the first time. For accomplishing the purpose, the adult beetles were collected by pitfall traps in the deciduous forest of Mt. Palgongsan, southern Korea. They have been reared under the laboratory condition of 16L: 8D at 20°C. The first instar larvae were obtained by isolating eggs after oviposition and were kept at the same condition. In the present study, external morphology of the first instar larva of this subspecies are described and its important character states and comparisons with the kin species are also discussed. [source]

Inter- and intraspecific differences in climatically mediated phenological change in coexisting Triturus species

GLOBAL CHANGE BIOLOGY, Issue 6 2006
ELIZABETH A. CHADWICK
Abstract Climate and weather affect phenological events in a wide range of taxa, and future changes might disrupt ecological interactions. Amphibians are particularly sensitive to climate, but few studies have addressed climatically mediated change in the phenology of closely related species or sexes. Here, we test the hypothesis that changes in spring temperatures result in phenological change among Triturus, and we examine inter- and intraspecific differences in response. Coexisting populations of Triturus helveticus and Triturus vulgaris at Llysdinam pond in mid-Wales (53°12,59,N 3°27,3,W) were monitored using pitfall traps along a drift fence during 1981,1987, and again in 1997,2005. Spring temperature over the same period explained up to 74% of between-year variability in median arrival date, with a significant advance of 2,5 days with every degree centigrade increase. Changes were greater for males than females of both species, and greater for T. helveticus than T. vulgaris within sexes, resulting in an increasing temporal separation between arrivals of male T. helveticus and all other groups. These data illustrate for the first time how climatic change might have differential effects on sympatric species and on the two sexes. [source]

Patterns of ant species richness along elevational gradients in an arid ecosystem

GLOBAL ECOLOGY, Issue 2 2003
Nathan J. Sanders
ABSTRACT Aim In this study, we examine patterns of local and regional ant species richness along three elevational gradients in an arid ecosystem. In addition, we test the hypothesis that changes in ant species richness with elevation are related to elevation-dependent changes in climate and available area. Location Spring Mountains, Nevada, U.S.A. Methods We used pitfall traps placed at each 100-m elevational band in three canyons in the Spring Mountains. We compiled climate data from 68 nearby weather stations. We used multiple regression analysis to examine the effects of annual precipitation, average July precipitation, and maximum and minimum July temperature on ant species richness at each elevational band. Results We found that patterns of local ant species richness differed among the three gradients we sampled. Ant species richness increased linearly with elevation along two transects and peaked at mid-elevation along a third transect. This suggests that patterns of species richness based on data from single transects may not generalize to larger spatial scales. Cluster analysis of community similarity revealed a high-elevation species assemblage largely distinct from that of lower elevations. Major changes in the identity of ant species present along elevational gradients tended to coincide with changes in the dominant vegetation. Regional species richness, defined here as the total number of unique species within an elevational band in all three gradients combined, tended to increase with increasing elevation. Available area decreased with increasing elevation. Area was therefore correlated negatively with ant species richness and did not explain elevational patterns of ant species richness in the Spring Mountains. Mean July maximum and minimum temperature, July precipitation and annual precipitation combined to explain 80% of the variation in ant species richness. Main conclusions Our results suggest that in arid ecosystems, species richness for some taxa may be highest at high elevations, where lower temperatures and higher precipitation may support higher levels of primary production and cause lower levels of physiological stress. [source]

Consequences for biodiversity of reducing inputs to upland temperate pastures: effects on beetles (Coleoptera) of cessation of nitrogen fertilizer application and reductions in stocking rates of sheep

GRASS & FORAGE SCIENCE, Issue 2 2004
P. Dennis
Abstract Current policies for upland pasture management in the UK encourage the integration of environmental objectives with livestock production through extensification of grazing systems. This study tested the hypothesis that a greater sward height in the summer would increase the diversity and abundance of grassland beetles (Coleoptera) as has been demonstrated for insects of indigenous grasslands. The hypothesis was tested with an experiment on an upland sheep pasture in mid-Wales. Experimental treatments received different nitrogen fertilizer inputs (0 or 50 kg ha,1), sheep stocking densities (12 or 9 ewes ha,1) and average sward heights in summer were constrained to 3·5 or 5·5 cm by conserving surplus grass for silage in subplots. Five treatments, replicated in three randomized blocks, combined the two stocking densities and two sward heights without nitrogen fertilizer inputs, with the fifth combining the higher stocking density, shortest sward height and the nitrogen fertilizer input. Beetles were sampled with twelve pitfall traps in each of the fifteen plots from June to September in 1993 and 1995. In years 1 (1993) and 3 (1995) of the experiment, more Coleoptera species occurred in the tall sward (an average of nine species in addition to the forty-one species present in the sward with the conventional sward height). Continuously grazed as opposed to ensiled subplots supported more beetle species but fewer individuals. Species composition of ground (Carabidae) and rove (Staphylinidae) beetles varied between treatments more than the arithmetic differences in species number. The experimental results supported the hypothesis but the benefits of taller swards to species diversity were small in the sown pastures of the study compared with indigenous upland grasslands (c. 33% fewer species). Inheritance effects of drainage, fertilizer and lime inputs, and the different species and management of cultivated pastures, may constrain the conservation benefits of altered pasture management compared with indigenous grasslands. [source]

Long-term exposure to elevated CO2 in a Florida scrub-oak forest increases herbivore densities but has no effect on other arthropod guilds

INSECT CONSERVATION AND DIVERSITY, Issue 2 2010
PETER STILING
Abstract., 1.,This study uses pitfall traps and sticky traps to examine the effects of elevated CO2 on the densities of insect herbivores, insectivores, and detritivores. 2.,Pitfall trapping for the last 3 years of 11 years of continuously elevated CO2 revealed increases of insect herbivore species such as Thysanoptera (thrips), Hemiptera, and Lepidoptera, but no effects on insectivores such as spiders, parasitic wasps, and ants; or on detritivores such as Diptera (flies), Psocoptera (book lice), Blattodea (cockroaches), Collembola (spring tails), Orthoptera (crickets), and Coleoptera (beetles). 3.,As the bottom-up effects of elevated CO2 are transmitted through plants to herbivores, they do not appear to reach insect natural enemies or decomposers. [source]

When the prairie varies: the importance of site characteristics for strategising insect conservation

INSECT CONSERVATION AND DIVERSITY, Issue 4 2009
CHRIS LOONEY
Abstract., 1.,The bunchgrass prairies of the Palouse region in eastern Washington state and adjacent Idaho have been mostly converted to agriculture in the past century. Prairie habitat currently exists only on small remnants scattered across the landscape. 2.,The invertebrate fauna of these habitat remnants is poorly known, both in terms of species diversity and community composition. 3.,Baited pitfall traps were used to sample carrion-attracted beetles during June and July of 2003 from high-quality prairie remnants of varying size and soil characteristics. 4.,Twenty-three beetle species in five families were found. Species richness and Shannon-Wiener diversity were not significantly correlated with habitat area or perimeter,area ratio. 5.,Beetle abundance and community structure were strongly correlated with soil characteristics. Deeper, loessal soils had greater overall beetle abundance than shallower, rocky soils, although some species were more frequently captured in shallower, rocky soil sites. 6.,Conservation plans emphasising only remnant size and condition do not sufficiently capture variability in insect communities across Palouse prairie remnants. [source]

Fine-scale heterogeneity in beetle assemblages under co-occurring Eucalyptus in the same subgenus

JOURNAL OF BIOGEOGRAPHY, Issue 10 2010
Philip S. Barton
Abstract Aim, Insect biodiversity is often positively associated with habitat heterogeneity. However, this relationship depends on spatial scale, with most studies focused on differences between habitats at large scales with a variety of forest tree species. We examined fine-scale heterogeneity in ground-dwelling beetle assemblages under co-occurring trees in the same subgenus: Eucalyptus melliodora A. Cunn. ex Schauer and E. blakelyi Maiden (Myrtaceae). Location, Critically endangered grassy woodland near Canberra, south-eastern Australia. Methods, We used pitfall traps and Tullgren funnels to sample ground-dwelling beetles from the litter environment under 47 trees, and examined differences in diversity and composition at spatial scales ranging from 100 to 1000 m. Results, Beetle assemblages under the two tree species had distinctive differences in diversity and composition. We found that E. melliodora supported a higher richness and abundance of beetles, but had higher compositional similarity among samples. In contrast, E. blakelyi had a lower abundance and species richness of beetles, but more variability in species composition among samples. Main conclusions, Our study shows that heterogeneity in litter habitat under co-occurring and closely related eucalypt species can influence beetle assemblages at spatial scales of just hundreds of metres. The differential contribution to fine-scale alpha and beta diversity by each eucalypt can be exploited for conservation purposes by ensuring an appropriate mix of the two species in the temperate woodlands where they co-occur. This would help not only to maximize biodiversity at landscape scales, but also to maintain heterogeneity in species richness, trophic function and biomass at fine spatial scales. [source]

Contrasting responses of arable spiders to the landscape matrix at different spatial scales

JOURNAL OF BIOGEOGRAPHY, Issue 1 2008
Martin H. Schmidt
Abstract Aim, Animal communities can be influenced by the composition of the surrounding landscape through immigration. Depending on habitat preferences, however, the effect of the landscape matrix can be positive or negative and can vary with scale. We tested this idea with arable spiders and tried to infer dispersal distances from relationships between local density and landscape composition at different spatial scales. Location, Thirty-eight landscapes around the cities of Göttingen and Giessen, Germany. Methods, Spiders were captured with pitfall traps in one field of winter wheat in each landscape. Landscape composition around the fields was characterized at 11 scales from 95 m to 3 km radius by land-use mapping and subsequent GIS analysis. Correlation tests were performed between landscape composition and local densities or species richness. Results, In both study regions, local species richness was enhanced by non-crop habitats on a landscape scale. The overall densities of wolf spiders (Lycosidae), long-jawed spiders (Tetragnathidae), crab spiders (Thomisidae), and dwarf sheet spiders (Hahniidae) increased significantly in landscapes with high percentages of non-crop habitats. Out of the 40 species tested, 19 responded positively to the percentage of non-crop habitats in the surrounding landscape, and five responded negatively. Depending on the species, the spatial scales with the highest explanatory power ranged from 95 m to 3 km radius around the study fields, potentially reflecting dispersal distances. Main conclusions, Arable spider species showed contrasting responses to the landscape context with respect both to the direction and to the spatial scale of the relationship. The variation in landscape requirements among species ensures high spider densities in a wide range of situations, which contributes to ecosystem resilience. However, species richness of arable spiders depends on heterogeneous landscapes with high percentages of non-crop habitats. [source]

Colonization success of carabid beetles on Baltic islands

JOURNAL OF BIOGEOGRAPHY, Issue 4 2000
D. Johan Kotze
Abstract Aims (1) To test whether there is a significant increase in carabid species richness with an increase in island size and, if so, if it is due to island area per se or habitat diversity. (2) To investigate whether scattered islands accumulate species quicker than islands close to each other, per island size. (3) To investigate changes in the proportions of carabid wing morphs between the Finnish mainland and islands in the Baltic Sea. Location Islands in the south-western archipelago of Finland, in the Baltic Sea. Methods Carabid beetles were collected using pitfall traps (diameter, 65 mm; volume, 170 mL), half-filled with an ethylene-glycol,water mixture, from 22 May to 20 September 1993 on 24 islands. Island size varied between 0.5 and c. 7000 ha, and each island had between one and four habitat types sampled. Results A total of 61 carabid species were captured on these islands. Pterostichus niger was numerically dominant on 15 of the 24 islands and made up 34.5% of the total catch. The islands had a significantly higher proportion of brachypterous species compared to the Finnish mainland. The islands also accumulated species at a much slower rate (z = 0.06) than that generally observed in the literature, and, for carabids, a mainly predacious group, habitat diversity had little predictive power in explaining species richness. Islands close to each other (a few hundred metres apart) accumulated species at a slower rate than did scattered islands, as island size increased. Main conclusions Although carabids disperse relatively easily to remote islands (perhaps a result of low Baltic Sea salinity and short interisland distances), colonization success appears to depend on a multitude of factors, including availability of suitable habitat on these islands, competitive superiority, survival ability during dispersal and island arrival sequence. [source]

Preliminary investigations into a potential ant invader in Kruger National Park, South Africa

AFRICAN JOURNAL OF ECOLOGY, Issue 3 2010
Hendrik Sithole
Abstract The super-abundance of Lepisiota incisa (Forel) in settlement areas of Kruger National Park, South Africa has raised concerns that it might be exotic and could negatively impact on natural ecosystems. We documented the current distribution of this ant species around the main settlement in Kruger, assessed how ant diversity varies across habitats, and investigated potential mechanisms facilitating dominance by L. incisa. Around the main camp of Skukuza, pitfall traps were set in five habitats differing in anthropogenic influence. Baiting trails were conducted to determine whether L. incisa and native ants differed in numerical and behavioural dominance. Aggression assays were performed on L. incisa to provide information on colony structure. Although L. incisa was found in all habitats, it had a significantly higher abundance in gardens and appears confined to human-disturbed areas. It was numerically dominant recruiting more workers to food baits than all other ant species combined. Aggression levels were low between most nests of L. incisa indicating a potential supercolony structure. More information is urgently needed on the genetics, physiology and origins of L. incisa, and monitoring of its current distribution is recommended. This species warrants attention because there may be significant potential for overseas invasion. Résumé La surabondance de Lepisiota incisa (Forel) dans des zones d'installations du Parc National Kruger, en Afrique du Sud, a suscité des inquiétudes quant au fait que cette espèce pourrait être exotique et avoir un impact négatif sur des écosystèmes naturels. Nous avons documenté la distribution actuelle de cette espèce de fourmi autour de la principale installation dans le Kruger, évalué comment la diversité des fourmis varie selon les habitats et étudié les mécanismes éventuels qui pourraient faciliter la dominance de L. incisa. On a installé des pièges autour du camp principal de Skukuza, dans cinq habitats où l'influence anthropogénique diffère. On a réalisé des pistes appâts pour déterminer si L. incisa et les fourmis indigènes différaient en matière de dominance numérique et comportementale. Nous avons fait des essais d'agression sur L. incisa pour donner des informations sur la structure de la colonie. Bien que l'on ait trouvéL. incisa dans tous les habitats, elle était beaucoup plus abondante dans les jardins et elle semble se confiner aux endroits perturbés par les hommes. Elle était numériquement dominante, recrutant plus d'ouvrières pour les appâts que toutes les autres espèces mises ensemble. Le niveau d'agression entre la plupart des nids de L. incisaétait bas, ce qui indique peut-être une structure de super-colonie. Il faut obtenir d'urgence d'autres informations sur la génétique, la physiologie et les origines de L. incisa et l'on recommande de faire le suivi de sa distribution actuelle. Cette espèce mérite l'attention parce qu'elle peut certainement être une espèce invasive outre-mer. [source]

Spiders as potential indicators of elephant-induced habitat changes in endemic sand forest, Maputaland, South Africa

AFRICAN JOURNAL OF ECOLOGY, Issue 2 2010
Charles R. Haddad
Abstract Elephant impacts on spider assemblages, and the potential use of spiders as indicators of habitat changes was assessed in central Maputaland, South Africa. Three habitats, namely undisturbed sand forest, elephant disturbed sand forest and mixed woodland, were sampled. To ensure a thorough representation of all spider guilds, spiders were collected by tree beating, sweep netting, active searching, leaf litter sifting and pitfall traps. In total, 2808 individual spiders, representing 36 families, 144 determined genera and 251 species were collected. Spider abundance was highest in the undisturbed sand forest (n = 1129, S = 179), followed by elephant disturbed sand forest (n = 1006, S = 165) and mixed woodland (n = 673, S = 171). Assemblages of the two sand forests were more similar than to the mixed woodland assemblage. Active hunting species were indicators of the more open vegetation of elephant disturbed sand forest (six active hunters, no web-builders) and mixed woodland (ten active hunters, one web-builder), whereas web-builders are indicators of the dense, complex vegetation structure of undisturbed sand forest (six web-builders, three active hunters). Elephant-induced changes to the vegetation structure in this high diversity, high endemism region result in changes in the composition of spider assemblages, and may need to be mitigated by management intervention. Résumé L'impact des éléphants sur les assemblages d'araignées, et l'utilisation éventuelle des araignées comme indicateurs de changements des habitats, ont étéévalués dans le centre du Maputaland, en Afrique du Sud. Trois habitats ont étééchantillonnés, à savoir la forêt sableuse intacte, la forêt sableuse perturbée par des éléphants et la forêt mixte. Pour garantir une représentation complète de toutes les guildes d'araignées, on a récolté des araignées en frappant sur les arbres, en agitant des filets, en pratiquant une recherche active, en tamisant la litière de feuilles, et avec des pièges. Au total, on a récolté 2 808 araignées; représentant 36 familles, 144 genres déterminés et 251 espèces. L'abondance d'araignées était la plus grande dans la forêt sableuse non perturbée (n = 1129, S = 179), suivie par la forêt sableuse perturbée par les éléphants (n = 1006, S = 165), puis par la forêt mixte (n = 673, S = 171). Les assemblages des deux forêts sableuses étaient plus semblables entre eux qu'avec celui de la forêt mixte. Les espèces d'araignées qui chassent activement étaient des indicateurs de la végétation plus ouverte de la forêt perturbée par les éléphants (six chasseurs actifs, aucun constructeur de toile) et de la forêt mixte (dix chasseurs actifs, un constructeur de toile), alors que les constructeurs de toile étaient des indicateurs de la structure dense et complexe de la végétation de la forêt sableuse intacte (six constructeurs de toile, trois chasseurs actifs). Les éléphants induisaient des changements dans la structure de la végétation de cette région à la diversitéélevée et d'un fort endémisme, ce qui entraînait des modifications de la composition des assemblages d'araignées. Cela pourrait devoir être atténué par une intervention de la gestion. [source]

Turnover in flightless invertebrate species composition over different spatial scales in Afrotemperate forest in the Drakensberg, South Africa

AFRICAN JOURNAL OF ECOLOGY, Issue 3 2009
Charmaine Uys
Abstract An understanding of species turnover at different spatial scales and the influence of environmental variables including distance are important for conservation planning and management. Ground dwelling, flightless invertebrates have poor dispersal abilities and other taxa may not be effective as surrogates. This is an important consideration for biodiversity conservation in Afrotemperate forests of the Drakensberg Mountains, South Africa, where flightless invertebrates are geographically isolated by the naturally fragmented state of forests. Seventeen Afrotemperate forests in four reserves across the Drakensberg were sampled using soil and leaf litter sampling, pitfall traps, active search quadrats and tree beats. Seventy-two species were recorded, comprising 31 mollusc, nine earthworm, one onychophoran, six centipede, twelve millipede and thirteen ant species. Canonical correspondence analysis indicated that latitude (distance); fire history (disturbance) and mean annual precipitation were the most important factors governing invertebrate assemblage composition. ,sim measurements detected change in species at all spatial scales investigated, but no clear trends were evident. Distance or spatial scale alone does not explain species turnover and community composition. Effective selection of target areas, therefore, requires species level information to identify species of special concern. Résumé Une bonne compréhension de la rotation des espèces à différentes échelles spatiales et de l'influence des variables environnementales, y compris de la distance, est importante pour la planification et la gestion de la conservation. Les invertébrés qui vivent dans le sol, ceux qui ne volent pas, n'ont que de faibles capacités de se disperser, et d'autres taxons peuvent ne pas être des substituts efficaces. Ceci pourrait être une réflexion importante pour la conservation de la biodiversité dans les forêts afro-tempérées des monts Drakensberg, en Afrique du Sud, où des invertébrés qui ne volent pas sont isolés géographiquement par l'état naturellement fragmenté des forêts. On a prélevé des échantillons dans 17 forêts afro-tempérées, dans quatre réserves du Drakensberg, en utilisant des échantillons de sols et de litière de feuilles, des pièges, la recherche active dans des quadrats et le battage d'arbres. On a enregistré 72 espèces comprenant 31 mollusques, neuf vers de terre, un onychophore, six centipèdes, 12 mille-pattes et 13 fourmis. L'analyse canonique des correspondances a indiqué que la latitude (distance), l'historique des feux (perturbations) et les précipitations annuelles moyennes étaient les facteurs les plus importants pour la composition des assemblages d'invertébrés. Des mesures de ,sim ont détecté des changements d'espèces dans toutes les échelles spatiales étudiées, mais aucune tendance nette n'était visible. L'échelle de distance ou d'espace n'explique pas seule la rotation des espèces et la composition de la communauté. La sélection effective de zones cibles requiert donc des informations au niveau des espèces pour pouvoir identifier les espèces dont le statut est particulièrement inquiétant. [source]

Post-dispersal predation of Taraxacum officinale (dandelion) seed

JOURNAL OF ECOLOGY, Issue 2 2005
ALOIS HONEK
Summary 1The importance of predation in determining the fate of post-dispersal dandelion (Taraxacum officinale) seed was investigated. Flowering, seed dispersal, seedling establishment, seed predation and seed predator abundance were recorded in 2002 and 2003, at two sites. Number of flowers were counted in 1-m2 plots, wind-borne seeds were collected in water traps, invertebrate seed predation was estimated from the rate of removal of dandelion seeds exposed on the ground and invertebrate activity density was determined by using pitfall traps. The censuses were made at 2- to 3-day intervals. 2Seed dispersal occurred 10 days after flowering. Although some seeds were blown away, 3.7,24.2 × 103 seeds m,2 fell to the ground. Four weeks after the peak in seed dispersal 0.7,3.1% of these seeds germinated. Three weeks later only 11,13% of the dispersed seed remained on the ground and most of these were damaged, the remainder presumably having been removed by predators. 3Predation of exposed seeds was low before seed dispersal but increased after its onset, in parallel with increases in the number of seeds present on the ground and in the activity density of adults of a seed-consuming carabid, Amara montivaga. 4In cafeteria experiments in which the seeds of 28 perennial and annual herbs were provided A. montivaga consumed the most dandelion seeds, followed by nine other Amara species. In no-choice experiments, under field conditions, A. montivaga consumed six seeds day,1. 5Post-dispersal predation, mainly due to aggregation of a single ground beetle species, was more important than that which occurred prior to dispersal. Although predators destroyed c. 97% of the seeds, the effect on dandelion population biology is likely to be small. 6Post-dispersal seed predation may nevertheless be important in other species, as aggregates of large invertebrate predators can consume large quantities of seed. [source]

Influence of within-field position and adjoining habitat on carabid beetle assemblages in winter wheat

AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2010
M. Anjum-Zubair
1The influence of within-field position and adjoining habitat on carabid beetles was studied in 20 winter wheat fields in ten different Swiss agricultural landscapes. In each landscape, two winter wheat fields (one with adjoining sown wildflower area and one with adjoining grassy margin) were investigated. 2Carabid beetles were caught in pitfall traps 3 and 30 m from the edge in each of the 20 wheat fields. Significantly more individuals were found in the centres (30-m position) than at the edges (3-m position). Conversely, species richness was significantly higher at the field edges than in the centres. 3Of the ten most abundant species, Poecilus cupreus, Agonum muelleri and Pterostichus melanarius were significantly more abundant in the field centres than at the edges. Harpalus rufipes was significantly more abundant in the fields adjoining sown wildflower areas than in the fields adjoining grassy margins. 4In conclusion, the response of carabid beetles to within-field position and adjoining habitats was species specific. This needs to be taken into account in habitat management for biodiversity conservation and pest control. [source]

Long-term effects of imidacloprid on the abundance of surface- and soil-active nontarget fauna in turf

AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2009
Daniel C. Peck
Abstract 1Outbreaks of root-feeding scarab larvae in turfgrass are widely managed through preventive applications of imidacloprid. Long-residual activity and application before feasible scouting probably lead to its overuse and overexposure. 2Recent investigations revealed a selective impact of imidacloprid (not trichlorfon or halofenozide) on certain nontarget turf arthropods, motivating the present study on the persistence of abundance effects over 6 years of annual applications. 3Arthropods were sampled monthly (July to October) in replicated plots using soil core heat extraction and pitfall traps to quantify soil- and surface-active arthropods. Captures were identified to class, order or family. The most represented taxa were analysed to test for cumulative effects and their change over season and year. 4Imidacloprid had no impact on pitfall captures, although the abundance of Hemiptera, Thysanoptera, Coleoptera and Collembola was suppressed in soil core captures. Among beetles, impact was expressed in adults (not larvae), and in Carabidae and Staphylinidae (not Chrysomelidae or Curculionidae). Among springtails, impact was expressed in Entomobryomorpha (not Poduromorpha or Symphypleona). Impact did not diminish with year but there was variable recovery between applications. 5There may therefore be a diverging response of soil- and surface-active fauna to the nontarget impacts of imidacloprid. The suppression of predaceous (not phytophagous) beetles indicates an indirect effect mediated through declines in prey populations. 6The magnitude of abundance effects confirms that the balance between target and nontarget impact should be explicitly examined. Implications are discussed with respect to functional relevance for nutrient cycling and the natural regulation of pests. [source]

Organic versus conventional management in an apple orchard: effects of fertilization and tree-row management on ground-dwelling predaceous arthropods

AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 2 2009
M. Miñarro
Abstract 1,Organic and conventional management of apple orchards may have a different effect on arthropod communities. 2,We conducted a 3-year study to assess the effect of two strategies of fertilizer treatment (organic versus chemical) and three tree-row management systems (straw mulching, tillage and herbicide) on activity-density and biodiversity of epigeic predators. Ground beetles (Carabidae), rove beetles (Staphylinidae), ants (Formicidae) and spiders (Araneae) were sampled monthly with pitfall traps in the same apple orchard during 2003, 2004 and 2005. 3,A total of 4978 individuals were collected. Carabids (56.8% of the total catches) were the most abundant taxonomic group, followed by spiders (20.7%), ants (14.8%) and rove beetles (7.7%). Tree-row management had a greater influence on predator catches than fertilizer treatment. Total predator catches were lower under the mulch. Mulching also reduced carabid abundance, but increased staphylinid catches. 4,Tree row management also had a significant effect on biodiversity parameters. Species richness did not significantly differ among treatments for ants, spiders or the total catches, but was higher on herbicide-treated plots for carabids and on mulched plots for staphylinids. Shannon,Wiener's diversity index was significantly greater in the mulched and herbicide treated plots for total predators and carabids. For staphylinids, this index was significantly greater on the mulched plots. Fertilizer application strategy only influenced the species richness of rove beetles, which was greater in the chemically-treated plots. 5,The results showed that a change from conventional to organic fertilizer treatment of apple trees may be performed without differential effects on predator activity-density or biodiversity. However, a change from herbicide treatment to mulching or mechanical weed control may be significant, depending on the taxonomic group. [source]

Effects of ground cover (straw and compost) on the abundance of natural enemies and soil macro invertebrates in vineyards

AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2007
Linda J. Thomson
Abstract 1,Herbicides are commonly applied under grapevines in Australia to remove weeds and thereby to avoid water loss through transpiration. 2,Interest in sustainability promotes a reduction in chemical inputs, including herbicides, leading to trials with surface mulches to suppress weeds. 3,Surface mulches may also influence the abundance of a range of invertebrates. Potentially, an increase in natural enemies will contribute to pest control and encourage a reduction in pesticide application. 4,We used three trapping methods and direct soil sampling to assess invertebrates at ground level, in the canopy and in the soil to determine the influence of mulch on natural enemies, potential pests and soil macroinvertebrates, including earthworms. 5,Collections sorted to family demonstrated that the addition of straw or compost mulches increased natural enemies collected with pitfall traps and soil organisms. However, there was no clear indication of the overall superiority of either mulch. 6,Abundance of ground beetles, parasitoid Hymenoptera and spiders collected with pitfall traps were increased by the addition of mulches. In the canopy, predatory and parasitic Diptera and predatory Hemiptera increased after mulching. 7,Earthworms collected by hand sorting soil increased with straw mulching. 8,No influence on pests was detected. Although Lepidoptera and Sigmurethra, collected in pitfall traps, increased with straw mulching, neither included pest species. 9,The results are discussed with reference to the potential economic impact of mulches. [source]

Potential of a synthetic aggregation pheromone for integrated pest management of Colorado potato beetle

AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 1 2006
T. P. Kuhar
Abstract 1The relative number of colonizing adult Colorado potato beetles (CPB) Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) coming to pitfall traps baited with the aggregation pheromone (S)-3,7-dimethyl-2-oxo-oct-6-ene-1,3-diol [(S)-CPB I] and the use of the pheromone in a trap crop pest management strategy were evaluated in the field for the first time. 2More than five-fold more adult L. decemlineata were caught in pitfall traps baited with the pheromone compared with controls. However, attraction to the pheromone diminished after 5 days in the field. 3In the trap crop management strategy, more colonizing adults were present in pheromone-treated rows of potatoes compared with untreated middle rows. 4Significantly fewer L. decemlineata egg masses and larvae were found in potato plots that were bordered by pheromone-treated rows, or bordered by imidacloprid + pheromone-treated rows, or rows treated at-planting with imidacloprid compared with untreated (control) potato plots. 5Densities of L. decemlineata egg masses and larvae and percentage defoliation were significantly lower, and marketable tuber yield significantly higher, in conventional imidacloprid-treated potatoes compared with all other treatments. 6Although our results demonstrate the potential for use of the aggregation pheromone in the management of L. decemlineata in the field, more research is needed to optimize the release rates of the attractant and incorporate control methods for cohabiting pests. [source]

Endectocide residues affect insect attraction to dung from treated cattle: implications for toxicity tests

MEDICAL AND VETERINARY ENTOMOLOGY, Issue 4 2007
K. D. FLOATE
Abstract A 3-year study was performed in southern Alberta, Canada to assess the effect of endectocide residues on the attractiveness of cattle dung to colonizing insects. In 2003 and 2004, insect captures were compared between pitfall traps baited with dung of untreated cattle and paired traps baited with dung of cattle that had been treated 7 days previously with topically applied doramectin, eprinomectin, ivermectin or moxidectin. Faecal residues associated with each compound affected insect captures in both spring and autumn of each year. Effects were detected (P < 0.05) for a total of 94 cases representing 27 insect taxa from 13 families in three orders (Coleoptera, Diptera, Hymenoptera). Two-fold differences in captures were common. Up to six-fold differences were observed. Eleven cases of attraction and 11 cases of repellency were associated with residues of doramectin. Eprinomectin tended to repel insects, with decreased captures for 19 of 29 cases of effect. Ivermectin showed a strong attractive effect, with increased captures for 17 of 25 cases. Moxidectin also showed a strong attractive effect, with increased captures for 17 of 18 cases. Comparisons between compounds suggested that results for doramectin best predicted results for eprinomectin and vice versa. In 2005, insect captures were compared between pitfall traps baited with dung of untreated cattle and traps baited with dung from cattle treated 3, 7 or 14 days previously with topically applied doramectin. Effects were detected in 14 cases plus one case of near significance (P= 0.053). Significant differences between control vs. days 3, 7 and/or 14 dung were detected in nine cases. Residues enhanced captures in seven of these cases. Day 14 dung affected captures in six of these cases. This study shows that endectocide residues can affect the number of insects attracted to colonize and oviposit in dung. Hence, the emergence of their offspring from field-colonized dung of untreated vs. endectocide-treated cattle should not be used as a measure of residue toxicity per se, but rather as a measure of ,insect activity'. Insect activity is a composite measure of residue toxicity, the number and species composition of insect colonists, and the mortality factors (e.g. predation, parasitism, competition) associated with the co-occurrence of these species in the dung pat. [source]

Investigating the effects of crop type, fertility management and crop protection on the activity of beneficial invertebrates in an extensive farm management comparison trial

ANNALS OF APPLIED BIOLOGY, Issue 2 2009
M.D. Eyre
Abstract The activity of 11 groups of invertebrates, mainly predators and parasites, was investigated in 2005 and 2006 in a plot trial system on a farm in northern England, where the effects of organic and conventional fertility and crop protection management were separated within different crop types. Invertebrate activity was assessed using pitfall traps and suction sampling. Mixed effects models indicated that crop type significantly affected activity in all 11 groups. Crop protection applications had only a limited impact on activity but fertility management had considerable effects in some crops. Most differences were in barley, wheat and grass/clover, with less in vegetable and bean plots. Carabidae, Lycosidae, Staphylinidae, Linyphiidae and Braconidae gave consistent responses to fertility management, with more activity of the first two groups in organic plots and more of the other three in conventional plots. However, Coccinellidae and Ichneumonidae were not consistent in their activity between crops. After the effects of crop type had been partialled out, a constrained ordination showed that the novel combination of organic fertility and conventional crop protection had the most influence on group activity, with the combination of organic fertility and organic crop protection also significant. Maximising the activity of beneficial invertebrates in organic and sustainable farming systems requires a basic understanding of the effects of both crop type and fertility management, as well as crop protection. [source]

Directionality of pre- and post-breeding migrations of a marbled newt population (Triturus marmoratus): implications for buffer zone management

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2005
P. Marty
Abstract 1.The marbled newt, Triturus marmoratus, is a vulnerable urodele species (listed on Annex IV of the European Habitats Directive). However, biological information about their migration and the terrestrial habitats they use is relatively scarce. In order to investigate the influence of the surrounding habitats of a local pond on the directions of pre- and post-breeding migrations, adult newts were monitored over two successive years (from February 2000 to June 2001) at a permanent pond in south-western France using a drift fence and pitfall traps. 2.In both sexes the entry and exit directions were non-randomly distributed. Furthermore, males and females generally followed similar directions facing an oak forest and avoiding barren areas. However, the directions followed by postbreeding migrants leaving the pond differed from those they followed when coming to the pond. 3.The distribution of captures around the pond was related to environmental factors, and more precisely to vegetation within the immediate surroundings of the pond. 4.The environmental conditions occurring at the end of the spring postbreeding migration differed greatly from those occurring during the winter prebreeding migration. Thus, vegetation does not exert similar attraction during the two migration periods. 5.This raises the importance of microhabitat diversity in the vicinity of the breeding pond, which provides a wide range of suitable shelters in different migration periods. Conservation planning must take into account the ecological requirements of this endangered species in managing buffer zones around the breeding sites. Copyright © 2005 John Wiley & Sons, Ltd. [source]