scholarly journals Does habitat structure influence capture probabilities? A study of reptiles in a eucalypt forest

2009 ◽  
Vol 36 (6) ◽  
pp. 509 ◽  
Author(s):  
Michael D. Craig ◽  
Andrew H. Grigg ◽  
Mark J. Garkaklis ◽  
Richard J. Hobbs ◽  
Carl D. Grant ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Vegetation Structure ◽  
Habitat Structure ◽  
Pitfall Traps ◽  
Total Removal ◽  
Habitat Types ◽  
Jarrah Forest ◽  
Future Studies ◽  
Eucalypt Forest ◽  
Structural Variables

Pitfall traps are commonly used to examine differences in reptile communities among habitat types and disturbance regimes that differ in structure. However, capture rates and probabilities may be influenced by habitat structure, which invalidates comparisons of relative abundance among habitat types. To assess whether pitfall traps provide accurate reflections of density and whether habitat structure affects capture probabilities, we trapped at six sites in various jarrah-forest habitat types in south-western Australia, then intensively searched 150-m2 total-removal plots around each pitfall grid to obtain absolute densities of reptiles. Pitfall captures were significantly correlated with numbers on total-removal plots for Hemiergis initialis and Lerista distinguenda, indicating that pitfall traps provided accurate reflections of density for these species. Capture probabilities of H. initialis and L. distinguenda and all reptiles combined showed no significant correlations with any structural variables, indicating that capture probabilities were consistent across sites. We conclude that trapping provided accurate estimates of relative abundance for some species and that capture probabilities were not influenced by vegetation structure. Because many studies use trapping to estimate abundances among habitat types, we encourage researchers to investigate how vegetation structure influences capture probabilities, so that general patterns can be determined; we also suggest improvements for any future studies.

scholarly journals A Pugnacious ant (Anoplolepis custodiens) confounds ant assemblage responses to bush encroachment

2020 ◽  
Author(s):  
Thinandavha Munyai ◽  
Stefan Foord ◽  
Rob Slotow ◽  
Nomathamsanqa Mkhize
Keyword(s):  
Vegetation Structure ◽  
Habitat Structure ◽  
Pitfall Traps ◽  
Clayey Soils ◽  
Site Specific ◽  
Negative Impacts ◽  
Anoplolepis Custodiens ◽  
Animal Communities ◽  
Ant Diversity ◽  
Behavioural Dominance

Habitat structure is a key determinant of variation in biodiversity. The effects of increased vertical and horizontal vegetation structure can result in marked shifts in animal communities. This is particularly true for ants in response to woody thickening, with predicted negative impacts on ant diversity. We used pitfall traps to study the response of epigeic ants in two co-occurring dominant habitats (closed and open) of an African savanna biome experiencing extensive woody thickening. Although species richness was higher in open habitats, evenness was significantly lower. Thickening explained significant amounts of variation in ant composition, but site-specific characteristics and seasonality were more important. These site-specific characteristics were largely linked to Anoplolepis custodiens, a species that were locally abundant in open habitats with clayey soils, where they often accounted for more than 90% of all ant activity. As A. custodiens also responds positively to disturbance, indiscriminate bush clearing could lead to knock on effects associated with the numerical and behavioural dominance of this species.

scholarly journals Efficiency of small mammal trapping in an Atlantic Forest fragmented landscape: the effects of trap type and position, seasonality and habitat

2014 ◽  
Vol 74 (3) ◽  
pp. 538-544 ◽  
Author(s):  
ALM Vieira ◽  
AS Pires ◽  
AF Nunes-Freitas ◽  
NM Oliveira ◽  
AS Resende ◽  
...  
Keyword(s):  
Ground Level ◽  
Fragmented Landscape ◽  
Pitfall Traps ◽  
Exact Test ◽  
Future Studies ◽  
Fisher's Exact Test ◽  
Fisher’S Exact Test ◽  
Trapping Methods ◽  
Mammal Communities ◽  
Total Effort

Trapping methods can strongly influence the sampling of mammal communities. This study compared the efficiency of the capture of small mammals in Sherman traps in two positions (at ground level and in trees) and pitfall traps in a fragmented landscape. Trapping sessions were carried out between October 2008 and October 2009 at two fragments (8 and 17 ha), an agroforest corridor between them, and the adjacent pasture. A total effort of 4622 trap-nights resulted in 155 captures of 137 individuals from six species. Pitfalls had greater success (4.03%), followed by Shermans on the ground (2.98%) and on trees (2.37%; χ2= 6.50, p = 0.04). Five species were caught in Sherman ground traps, four in pitfalls and just two on trees. There was no difference among trap types for marsupials (χ2 = 4.75; p = 0.09), while for rodents, pitfalls were more efficient than Shermans on the ground (Fisher's exact test, p = 0.02). As a result, the efficiency of each trap type differed among habitats, due to differences in their species composition. Pitfalls were more efficient in the rainy season (Fisher's exact test, p <0.0001) while Shermans on trees were more efficient in the dry season (Fisher's exact test, p = 0.009). There was no difference between seasons for Shermans on the ground (Fisher's exact test, p = 0.76). Considering the results found, we recommend that future studies of forest mammal communities, particularly those designed to test the effects of forest fragmentation, include combinations of different trap types.

scholarly journals The influence of shelterbelts in arable farmland on beneficial and pest invertebrates

2015 ◽  
Vol 68 ◽  
pp. 367-372
Author(s):  
M.M. Davidson ◽  
B.G. Howlett ◽  
R.C. Butler ◽  
N.M. Taylor ◽  
M.K. Walker
Keyword(s):  
Relative Abundance ◽  
Pest Species ◽  
Pitfall Traps ◽  
Arable Crops ◽  
Beneficial Insects ◽  
Arable Farmland ◽  
The Mean ◽  
Beneficial Insect ◽  
Abundance And Diversity ◽  
On Farm

Shelterbelts of Pinus radiata and Cupressus macrocarpa are common landscape features on arable farmland in New Zealand This study aimed to determine whether such shelterbelts could influence the relative abundance and diversity of beneficial and pest invertebrates commonly found in arable crops Window intercept yellow sticky and pitfall traps were placed next to shelterbelts or post and wire fences and also 50 m from these borders into adjacent crops on two arable farms in Canterbury and one in Wairarapa over 12 weeks in summer 2012 and autumn 2013 The abundance of given species/taxa varied considerably depending on farm location season and field border type However the mean number of beneficial insect species/taxa per trap did not vary markedly between field border types or adjacent crops while traps at shelterbelts or their adjacent crops caught more of some pest species/taxa than traps beside fences The pine/macrocarpa shelterbelts did not markedly increase relative abundance or diversity of beneficial insects

scholarly journals The effects of grazing and mowing on large marsh grasshopper, Stethophyma grossum (Orthoptera: Acrididae), populations in Western Europe: a review

2018 ◽  
Vol 27 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Jacqui Miller ◽  
Tim Gardiner
Keyword(s):  
Vegetation Structure ◽  
Western Europe ◽  
Conservation Management ◽  
Life Stages ◽  
Negative Effects ◽  
Habitat Types ◽  
The Uk ◽  
Grassland Habitats ◽  
Intensity Grazing ◽  
Refuge Areas

The large marsh grasshopper, Stethophymagrossum L. (Orthoptera: Acrididae), has undergone a significant range contraction in the UK and is now restricted to the bogs and mires of the New Forest and Dorset Heaths. In other parts of Western Europe, the species makes use of a wider range of wetland habitat types. Traditionally, many of these habitats would be managed through low intensity grazing, mowing, or both, and these measures are now often employed in the conservation management of wet grassland habitats. This paper reviews the effects of mowing and grazing on S.grossum populations, through looking at the potential impacts (both positive and negative) on different life stages of the grasshopper. Both techniques are valuable in the maintenance of an open and varied vegetation structure which is known to benefit S.grossum in all its life stages. However, grazing on very wet sites or at high intensity can result in trampling of vegetation and S.grossum eggs, and mowing which is too frequent may negatively affect populations through repeated losses of nymphs. Recommendations are given regarding the suitability of mowing and grazing for different habitats and intensity of management to generate the required vegetation structure. Measures are also outlined, such as the provision of unmown or ungrazed refuge areas, which can help reduce negative effects.

scholarly journals Distribusi dan Kemelimpahan Meiofauna di Hulu Sungai Code Yogyakarta

2012 ◽  
Vol 9 (2) ◽  
pp. 34 ◽  
Author(s):  
Riche - Hariyati
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
River Water ◽  
Relative Abundance ◽  
Horizontal Distribution ◽  
Water Current ◽  
Habitat Types ◽  
Chemical Parameter ◽  
Physico Chemical

This research is aimed to study distribution and abundance of meiofauna and the quality of physicochemicalcharacteristics of uppersite of code river and up stream river code Yogyakarta province. Samples weretaken using modified Pysto style corer and were located based on habitat types specific river, which are pool, riffle,rapid, left side and right side of water column. Sample taken four times for each zone. The parameter of for waterquality measured were dissolved oxygen. Water current, alkalinity and pHResult from the analysis showed that the abundance of meiofauna at code river the highest at left side zone.Which was 537.806 individu/m3 with relative abundance was 28,09% result from physico chemical parameter ofdissolved oxygenbetween 5,44 ppm – 6,0 ppm, alkalinity 20 ppm – 25 ppm , pH 7,10 – 7,18.and watercurrenntmeasured between 0,03 m/sec – 0,49 m/sec. The abundance of meiofauna at code river was dominated bygroup of Nematodes horizontal distribution of the fauna was the widest for Nematodes ostracoda, Rhizopoda andinsecta. Physico chemicalquality of code river water was relative good for meiofauna habitat and other waterorganisms

scholarly journals Rapid response of habitat structure and above-ground carbon storage to altered fire regimes in tropical savanna

2019 ◽  
Vol 16 (7) ◽  
pp. 1493-1503 ◽  
Author(s):  
Shaun R. Levick ◽  
Anna E. Richards ◽  
Garry D. Cook ◽  
Jon Schatz ◽  
Marcus Guderle ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Vegetation Structure ◽  
Habitat Structure ◽  
Canopy Structure ◽  
Three Dimensional ◽  
Canopy Cover ◽  
Fire Regimes ◽  
Dry Season ◽  
Airborne Lidar ◽  
Climate Conditions

Abstract. Fire regimes across the globe have been altered through changes in land use, land management, and climate conditions. Understanding how these modified fire regimes impact vegetation structure and dynamics is essential for informed biodiversity conservation and carbon management in savanna ecosystems. We used a fire experiment at the Territory Wildlife Park (TWP), northern Australia, to investigate the consequences of altered fire regimes for vertical habitat structure and above-ground carbon storage. We mapped vegetation three-dimensional (3-D) structure in high spatial resolution with airborne lidar across 18 replicated 1 ha plots of varying fire frequency and season treatments. We used lidar-derived canopy height and cover metrics to extrapolate field-based measures of woody biomass to the full extent of the experimental site (R2=0.82, RMSE = 7.35 t C ha−1) and analysed differences in above-ground carbon storage and canopy structure among treatments. Woody canopy cover and biomass were highest in the absence of fire (76 % and 39.8 t C ha−1) and lowest in plots burnt late in the dry season on a biennial basis (42 % and 18.2 t C ha−1). Woody canopy vertical profiles differed among all six fire treatments, with the greatest divergence in height classes <5 m. The magnitude of fire effects on vegetation structure varied along the environmental gradient underpinning the experiment, with less reduction in biomass in plots with deeper soils. Our results highlight the large extent to which fire management can shape woody structural patterns in savanna landscapes, even over time frames as short as a decade. The structural profile changes shown here, and the quantification of carbon reduction under late dry season burning, have important implications for habitat conservation, carbon sequestration, and emission reduction initiatives in the region.

Corrigendum to: Distribution and relative abundance of forest duikers in Dassioko Sud Forest Reserve (coastal Côte d'Ivoire)

2018 ◽  
Vol 45 (2) ◽  
pp. 194
Author(s):  
K. A. Yao ◽  
E. A. Bitty ◽  
K. B. Kassé ◽  
Y. C. Kouakou ◽  
K. H. Yaokokoré-Beibro ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Habitat Preferences ◽  
Habitat Type ◽  
Distribution Patterns ◽  
Encounter Rate ◽  
Line Transect ◽  
Habitat Types ◽  
Anthropogenic Pressures ◽  
Forest Reserve ◽  
Encounter Rates

Context Duikers play a vital role in maintaining forest ecosystems, as both seed dispersers and prey. In West Africa, duikers are also an important source of food and income; however, it is likely that some species are now being hunted at unsustainable levels. So as to contribute to duiker conservation, we used line-transect data and additional information on dung and track counts to estimate relative abundance and establish distribution patterns of forest duikers in Côte d'Ivoire's Dassioko Sud Forest Reserve (DSFR), a poorly known, remnant coastal rainforest. We also collected basic information on hunting pressure. Methods Forest duiker counts were made twice per month from July 2013 to March 2014 on six line transects of varying lengths (5.6–6.7km) and in different regions of the DSFR, representing different habitat types. The number of sightings per kilometre walked, defined as ‘encounter rate', was used to compute an index of relative abundance. We recorded all evidence of poachers and used these data to generate a poaching index (# poaching signs per kilometre) for different habitat types. Key results The DSFR has lost three of seven total forest duiker species and populations of the four remaining species are declining. Encounter rates were greatest for Philantomba maxwellii (0.46 indices km–1) and accounted for 68% of total encounters. Cephalophus niger, C. dorsalis and C. silvicultor were encountered at similar (0.07 indices km–1) but much lower rates. For all species, mean encounter rates were highest in degraded forest (0.38–0.73 indices km–1), followed by secondary (0.2–0.44 indices km–1) and primary (0.19–0.44 indices km–1) forest. Conclusions Of the four forest duiker species still present in the DSFR, the black, bay and yellow-backed duikers are the most affected by anthropogenic pressures. Duiker abundance in the DSFR varies with habitat type. This variation is apparently influenced by differences in forest structure, poaching pressure and proximity to villages. Implications The study provides baseline data for future managing of ungulate populations in the DSFR. We recommend that a biomonitoring study of duiker populations be initiated immediately to help determine population trends, investigate habitat preferences, and help curb illegal hunting activities in this important forest reserve.

Invertebrate predation of postdispersal seeds and juvenile seedlings of black spruce (Picea mariana) in the boreal forest of eastern Canada

2005 ◽  
Vol 35 (3) ◽  
pp. 674-681 ◽  
Author(s):  
Mathieu Côté ◽  
Jean Ferron ◽  
Réjean Gagnon
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Pitfall Traps ◽  
Invertebrate Predation ◽  
Habitat Types ◽  
Eastern Canada ◽  
Exclosure Experiment ◽  
Seedling Predation ◽  
Lichen Woodland ◽  
Abundance And Diversity

We used an extensive vertebrate exclosure experiment to evaluate black spruce (Picea mariana (Mill.) B.S.P.) postdispersal seed and seedling predation by invertebrates in three boreal habitats of Eastern Canada: recent burn, spruce–moss, and lichen woodland. Between 9% and 19% of seeds were eaten by invertebrates. Seed predation was higher in recent burns than in spruce–moss and lichen woodlands. Abundance and diversity of potential invertebrate seed consumers sampled in pitfall traps also varied among habitat types. Among the invertebrate seed consumers sampled, Myrmica spp. (Hymenoptera: Formicidae) and Pterostichus adstrictus (Eschscholtz, 1823) (Coleoptera: Carabidae) were the most numerous; Formica spp. (Hymenoptera: Formicidae) and Pterostichus punctatissimus (Randall, 1838) (Coleoptera: Carabidae) were also present. Between 2% and 12% of juvenile black spruce seedlings were eaten by invertebrates. The most important seedling consumers were slugs (molluscs). Invertebrate predation of seeds and seedlings was highest (19% and 12%) in recent burns, indicating that invertebrate predation may significantly influence black spruce regeneration in these sites.

Étude des relations entre les communautés piscicoles et les différents habitats d'une rivière nordique: notion d'habitat optimal

1982 ◽  
Vol 60 (12) ◽  
pp. 3344-3352
Author(s):  
Louise Savard ◽  
Guy Moreau
Keyword(s):  
Relative Abundance ◽  
Condition Factor ◽  
Northern Pike ◽  
Abundant Species ◽  
The Other ◽  
Coregonus Clupeaformis ◽  
Habitat Types ◽  
Linkage Cluster ◽  
Complete Linkage Cluster ◽  
Satellite Species

A complete linkage cluster analysis using the physical characteristics of the sampling sites has revealed the existence of five groups corresponding to five habitat types nonequally distributed in a northern Quebec river. According to the results of discriminant analysis using the relative abundance of the fish species present, these habitats support populations which differ by the relative abundance of species and not by the presence or absence of some particular species. A habitat is first characterized by a species living preferentially in this habitat, then by the other species inhabiting the area in an opportunistic way, and finally by some satellite species which do not seem to have any marked requirements. A habitat is considered as optimal for a species first if this species inhabits this area preferentially to others and secondly if this use is more advantageous for growth or condition factor. This seems to be confirmed for two of the most abundant species, northern pike (Esox lucius) and lake whitefish (Coregonus clupeaformis), both of which have a higher condition factor and a better growth in the part of the river where their optimal habitat is more frequently found.

Bryophyte relationships with environmental and structural variables in Tasmanian old-growth mixed eucalypt forest

2006 ◽  
Vol 54 (3) ◽  
pp. 239 ◽  
Author(s):  
P. A. M. Turner ◽  
J. B. Kirkpatrick ◽  
E. J. Pharo
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Canopy Cover ◽  
Basal Area ◽  
Mean Annual Temperature ◽  
Old Growth ◽  
Moss Species ◽  
Eucalypt Forest ◽  
Structural Variables ◽  
Negative Predictor

The species richness and species composition of bryophytes (mosses and liverworts) was recorded at 33 sites in Tasmanian old growth mixed eucalypt forest. A total of 202 bryophyte taxa were recorded, consisting of 115 liverworts and 87 mosses. This constitutes approximately one third of the total bryophyte flora for Tasmania. Mean liverwort species richness per site was higher than moss species richness. Latitude was found to be a positive predictor in all multiple regression models of bryophyte, moss and liverwort species richness. Mean annual temperature and rainfall of the driest month were positive predictors for bryophyte and liverwort species richness. Basal area of the treefern Dicksonia antarctica Labill. was a negative predictor of liverwort species richness. Latitude, variables relating to moisture, mean annual temperature, rainfall of the driest month and basal area of Dicksonia antarctica were the most significant components in predicting variation in bryophyte, moss and liverwort species composition. There were few relationships between the variables of canopy cover and soil nutrients and bryophyte species richness and composition. Substrate variables were found to be important components in predicting variation in moss and bryophyte species composition.

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