scholarly journals Impact of Horizontal Edge–Interior and Vertical Canopy–Understory Gradients on the Abundance and Diversity of Bark and Woodboring Beetles in Survey Traps

Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 573 ◽  
Author(s):  
Jon Sweeney ◽  
Cory Hughes ◽  
Vincent Webster ◽  
Chantelle Kostanowicz ◽  
Reginald Webster ◽  
...  

Semiochemical-baited intercept traps are important tools used to collect information about the presence/absence and population dynamics of forest insects. The performance of these tools is influenced by trap location along both horizontal edge–interior and vertical understory–canopy gradients. Consequently, the development of survey and detection programs requires both the development of effective traps and semiochemical lures but also deployment protocols to guide their use. We used field trapping experiments to examine the impact of both horizontal edge–interior and vertical understory–canopy gradients and their interactions with the species richness and abundance of Buprestidae, Cerambycidae and Curculionidae. Both gradients had significant effects on the diversity and abundance of all three families collected in traps and the pattern of gradient effects differed between the two experiments. In the first experiment, traps were deployed along transects involving large (>100 m) forest gaps and in the second experiment traps transected small (ca. 15 m) forest gaps. These results were consistent with the idea that gradient effects on the abundance and diversity of these three families of forest Coleoptera are context dependent. The results of this study suggest that monitoring programs for bark and woodboring beetles should deploy traps at multiple locations along both vertical understory–canopy and horizontal edge–interior gradients.

2002 ◽  
Vol 32 (1) ◽  
pp. 38-51 ◽  
Author(s):  
Steven G Newmaster ◽  
F Wayne Bell

In northern forests, cryptogams (spore producing plants) occupy a key position in forest ecosystem diversity and function. Forest harvesting and silvicultural practices have the potential to reduce cryptogam diversity. This project uses four blocks that were mechanically site prepared, planted with a single conifer species, and subsequently subjected to five conifer release treatments: (1) motor-manual cleaning, (2) mechanical brush cutting, (3) aerial application of triclopyr, (4) aerial application of glyphosate, and (5) control (untreated clearcut). Five 10 × 10 m subplots were installed in each of the five treatment plots and the uncut forest on the four blocks. Botanical surveys were conducted before and 1–5 years after treatments. Species richness and abundance, Shannon's and Heip's indices, and rank abundance diagrams clearly show that richness and abundance were affected by silvicultural treatments. Vegetation management treatments resulted in significant reductions in cryptogam diversity, to the point that only a few colonists and drought-tolerant species remained. Cryptogam diversity was ranked in the following order: forest > clearcut > mechanical clearing > herbicide treatment. Herbicide treatments had the greatest initial effect on species richness, species abundance, and diversity indices. Cryptogam diversity showed signs of recovery 5 years after treatments. Missed strips (untreated areas) within a clearcut provided a refuge for remnant communities of forest cryptogams that could play a key role in the rehabilitation forest diversity.


2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
David H. Branson

A continuing challenge in orthopteran ecology is to understand what determines grasshopper species diversity at a given site. In this study, the objective was to determine if variation in grasshopper abundance and diversity between 23 sites in western North Dakota (USA) could be explained by variation in plant species richness and diversity. In this system with relatively low plant diversity, grasshopper species richness and abundance were not significantly associated with plant species richness in either year. Although a number of significant associations between plant diversity and grasshopper diversity were found through regression analyses, results differed greatly between years indicating that plant species richness and diversity did not lead to strong effects on grasshopper diversity metrics. Plant species richness appears to be too coarse grained to lead to accurate predictions of grasshopper species richness in this system dominated by generalist grasshopper species.


2004 ◽  
Vol 52 (1) ◽  
pp. 23 ◽  
Author(s):  
Sarah J. Hill ◽  
Kristine French

Exclosure plots were used to determine the effect of fire and grazing on the structure of a grassy-woodland community. Eighteen months after fire and fence treatments were applied, the species richness, cover and composition of shrubs, trees, herbs and grasses were assessed and compared to pre-treatment censuses. Unburned plots had fewer shrub species and a lower abundance of shrubs, indicating the importance of fire in promoting regeneration of shrub species. Eucalypt species were more abundant and richer following the wildfire burn in summer, suggesting timing of fires is an important aspect in the establishment of the canopy species. Interactions between fire and grazing were found for the abundance of eucalypts (although weak) and resprouting eucalypts, suggesting a subtle interaction between fire and grazing shortly after fire. There was no effect of grazing and no interaction effect between fire and grazing on shrub species richness and abundance or tree species richness and seedling abundance.All plots showed a change in species composition despite treatment, and 46 species (32% of total richness) were recorded only in the final survey. The high rainfall during the 18-month study is likely to be an important factor in facilitating the establishment of species following all disturbances. This may have ameliorated the impact of grazing as abundant food was available throughout the woodland. The interaction between fire and grazing may be more important in structuring these grassy communities during periods of lower rainfall.


2018 ◽  
Vol 5 (13) ◽  
pp. 165
Author(s):  
Juan Manuel Pech Canché ◽  
Paola Deniss Coria Villegas ◽  
Ivette Alicia Chamorro-Florescano ◽  
José Lui Alanís Méndez ◽  
Miguel Ángel Lozano-Rodríguez

The term lunar phobia is used to explain the behavior that some nocturnal animals have to avoid periods with greater moonlight intensity. The aim was to determine the effect of the brightness of the new moon and the fullmoon on the richness, abundance and diversity of the phyllostomid bat community at the La Ceiba estate, Tuxpan, Veracruz, where the study was conducted from October 2013 to February 2014 using five mist nets for two nights per month. We captured 142 bats belonging to eight species, with Artibeus lituratus being the species with the highest records in both lunar phases (74 individuals). Although no signicant differences were found in diversity between the two lunar phases, greater cumulative species richness and abundance were recorded in the new moon (eight species, 118 individuals) than the full moon (five species, 24 individuals). The signicant decrease in abundance between the new moon and the full moon, mainly of small frugivorous species, indicates that lunar luminosity affects bat activity. It also has an effect on total species richness as three species were exclusively recorded in the new moon phase.


2021 ◽  
Author(s):  
Hamutahl Cohen ◽  
Monika Egerer ◽  
Summer-Solstice Thomas ◽  
Stacy M. Philpott

Abstract Context There is concern that urbanization threatens bees, a diverse group of economic importance. The impact of urbanization on bees is likely mediated by their phenotypic traits. Objectives We examine how urban cover and resource availability at local and landscape scales influences both species taxonomic and functional diversity in bees. Methods We used a combination of aerial netting and pan traps across six sampling periods to collect wild bees in 18 urban gardens spanning more than 125 km of the California central coast. We identified 3537 specimens to genus and, when possible, to species to obtain species richness and abundance at each site. For each species we measured a suite of bee traits, including body size, sociality, nesting location, nesting behavior, pollen-carrying structure, parasitism, and lecty. Results We found that increased garden size was positively associated with bee species richness and abundance. Somewhat counterintuitively, we found that urban cover surrounding gardens (2 km) was positively associated with bee species richness. Urban cover was also associated with the prevalence of certain bee traits, such as bees that excavate nests over those who rent, and bees with non-corbiculate structures. We suggest that urban habitats such as gardens can host a high number of bee species, but urbanization selects for species with specific traits. Conclusions These findings illustrate that local and landscape features both influence bee abundance, species richness, and the frequency of specific traits. We highlight the importance of trait-based approaches for assessing biodiversity in urban landscapes, and suggest conceptualizing urbanization as a process of habitat change rather than habitat loss.


1997 ◽  
Vol 24 (6) ◽  
pp. 727 ◽  
Author(s):  
Kristine French ◽  
Anita Zubovic

Bird communities in native coastal woodland were compared with those in woodland infested with Chrysanthemoides monilifera rotundata (bitou bush) in order to determine the impact of infestations of this weed on birds. Little evidence was found to suggest that bitou bush negatively affected the bird communities as a whole. Overall, the total number of birds in each type of habitat did not differ while numbers of species differed only at one area. Weed infestations have a differential impact on foraging groups. Canopy-feeding generalists and understorey insectivores showed differences in abundance and species richness in a few areas, with greater numbers in weed sites than in native sites. Temporal variation in weed-site use was also evident for canopy foragers. For these groups, weed infestations are providing at least some resources, although the details of resource use need to be investigated further. Species richness and abundance of birds relying almost exclusively on plant material were negatively affected by weed infestations, indicating that this foraging guild may not be provided with adequate resources in weed-infested habitats. Similarly, although numbers were low, scavengers and raptors also showed lower abundances and species richness in weed-infested habitats. For these foraging groups, management programmes to rehabilitate weed-infested habitats are likely to have a positive effect on numbers.


2017 ◽  
Vol 14 (2) ◽  
pp. 1 ◽  
Author(s):  
Noor Nasuha Abd Aziz ◽  
Siti Khairiyah Mohd Hatta ◽  
Idris Abd Ghani ◽  
Saiyid Jalaluddin Saiyid Shaifuddin

A study on abundance and diversity of Hymenoptera was conducted in Gunung Datuk, Rembau. Samplings were conducted from November 2014 to February 2015 using six Malaise traps. Three traps were placed at Site 1 at 700m height for high elevation and the remaining traps were placed at Site 2 at 200m height for low elevation. A total number of 221 Hymenopteran were collected which consist of nine families namely Ichneumonidae, Formicidae, Braconidae, Bethylidae, Evaniidae, Tiphiidae, Vespidae, Pompilidae and Apidae. In this study, 93 individuals were obtained from Site 1, comprising nine families and 43 morphospecies while 127 individuals were obtained from Site 2 with nine families and 45 morphospecies. Formicidae was the most dominant family collected from both sites with a total of 104 individuals while the least family recorded was Apidae with only one individual. Shannon’s Weiner Diversity Index (H’) showed Site 1 had the higher diversity value with H’ = 3.17 compared to Site 2 with value H’ = 3.12. For Evenness Index, Site 1 had higher value compared to Site 2 with E’ = 0.84 and E’ = 0.82 respectively. Moreover, for Margalef Richness Index, Site 1 recorded R’ = 9.24 while site two recorded R’ = 9.08 which concluded that Site 1 had higher species richness compared to Site 2. Paired t-test showed that both sites had no significant difference with p>0.05. Overall study showed that the diversity and abundance of Hymenoptera in Gunung Datuk were low since the value of H’ is less than 3.50.


Author(s):  
Jacqueline A Darrow ◽  
Amanda Calabro ◽  
Sara Gannon ◽  
Amanze Orusakwe ◽  
Rianne Esquivel ◽  
...  

Abstract Background Cerebrospinal fluid (CSF) biomarkers are increasingly used to confirm the accuracy of a clinical diagnosis of mild cognitive impairment or dementia due to Alzheimer disease (AD). Recent evidence suggests that fully automated assays reduce the impact of some preanalytical factors on the variability of these measures. This study evaluated the effect of several preanalytical variables common in clinical settings on the variability of CSF β-amyloid 1–42 (Aβ1–42) concentrations. Methods Aβ1–42 concentrations were measured using the LUMIPULSE G1200 from both freshly collected and frozen CSF samples. Preanalytic variables examined were: (1) patient fasting prior to CSF collection, (2) blood contamination of specimens, and (3) aliquoting specimens sequentially over the course of collection (i.e., CSF gradients). Results Patient fasting did not significantly affect CSF Aβ1–42 levels. While assessing gradient effects, Aβ1–42 concentrations remained stable within the first 5 1-mL aliquots. However, there is evidence of a gradient effect toward higher concentrations over successive aliquots. Aβ1–42 levels were stable when fresh CSF samples were spiked with up to 2.5% of blood. However, in frozen CSF samples, even 0.25% blood contamination significantly decreased Aβ1–42 concentrations. Conclusions The preanalytical variables examined here do not have significant effects on Aβ1–42 concentrations if fresh samples are processed within 2 h. However, a gradient effect can be observed on Aβ1–42 concentrations after the first 5 mL of collection and blood contamination has a significant impact on Aβ1–42 concentrations once specimens have been frozen.


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