Avian nest predation in modified and natural habitats in troprical Queensland: an exeperimental study.

1993 ◽  
Vol 20 (6) ◽  
pp. 711 ◽  
Author(s):  
WF Laurance ◽  
J Garesche ◽  
CW Payne

Predation on artificial avian ground-nests was assessed from March to December 1991 in rainforest and nearby modified habitats in tropical Queensland. Data from 610 experimental nests were used to determine relative predation intensity in five types of habitat or microhabitat. Nest predators were identified with live-traps, with baited grease-plates and by regular observations of 380 additional nests. Predation intensity was patchy but often heavy in forested habitats (rainforest interiors, secondary forest, rainforest-pasture edges, and a rainforest-secondary forest edge) and negligible in adjoining cattle pastures. Forest edges exhibited no obvious edge-interior gradients in predation intensity. Most predation occurred at night in rainforest (88%) and secondary forest (61%), and patterns of egg damage suggested that mammals were responsible for most (>71%) nest predation. A combined nest-predation and live-trapping experiment on six study plots revealed that the abundance of white-tailed rats (Uromys caudimaculatus) was a highly effective predictor of local predation intensity (F=30.15, r*2=0.85, P=0.004). One of Australia's largest rodents, the white-tailed rat may be a key opportunistic predator of some bird nests in north Queensland rainforest.

2002 ◽  
Vol 29 (4) ◽  
pp. 341 ◽  
Author(s):  
Lainie Berry

Predation rates of nests at human-induced habitat edges may be greater than in forest interior due to differences in predator assemblages and predator activity. I compared the predation rates on 192 artificial nests containing plasticine eggs placed in forest edge and interior sites at Bunyip State Park, Victoria. The nest-predation rates at the forest edge sites were significantly greater (mean = 52–58%) than that at the forest interior sites (mean = 30–39%). The relative rates of predation by birds compared with mammals were significantly greater at forest edge sites (mean = 78–94%) than at forest interior sites (mean = 36–67%). Higher rates of nest predation at forest edges appeared to be due to greater densities of avian predators such as the grey shrike-thrush (Colluricincla harmonica), and/or lower abundances of small mammals. However, biases towards certain predator types may mask real, or create false, patterns in predation rates of artificial nests. A better understanding of how predators respond to artificial nests compared with natural nests is required. Until then, results of predation studies that use artificial nests should be interpreted with caution.


Author(s):  
Noah Atkin ◽  
Cris Banks-Leite

It has been previously hypothesised that nest predation is higher at forest edges. This has important conservation implications for the increasingly fragmented U.K. climax community. I aimed to test the generality of this edge effect in a mixed deciduous forest fragment which borders open grassland. Artificial nests containing a combination of quail and plasticine eggs were used, at ground and arboreal levels. I found an overall edge effect on nest predation rates, however this effect was not specifically seen in ground nests. Ground nests experienced significantly higher levels of predation than arboreal nests. I suggest this edge effect is due in part to the steep productivity gradient over the ecotone.


2021 ◽  
pp. 1-11
Author(s):  
M. Soledad Vazquez ◽  
Lucía B. Zamora-Nasca ◽  
Mariano A. Rodriguez-Cabal ◽  
Guillermo C. Amico

2014 ◽  
Vol 7 (4) ◽  
pp. 720-732 ◽  
Author(s):  
Ondřej Sedláček ◽  
Martin Mikeš ◽  
Tomáš Albrecht ◽  
Jiří Reif ◽  
David Hořák

1972 ◽  
Vol 2 (2) ◽  
pp. 127-151 ◽  
Author(s):  
Yoshika Oniki ◽  
Edwin O. Willis

Abstract Birds that prey on arthropods flushed by army ants north of the eastern Amazon were studied at Serra do Navio and Reserva Ducke (Brazil) and at Nappi Creek and Bartica (Guyana). Regular ant-followers are two medium-sized antbirds (Percnostola rufifrons and Gymnopithys rufigula) and two smaller ones (Pithys albifrons and Hylophylax poecilonota), plus five woodcreepers of differing sizes (from very large Hylexetastes perrotti through Dendrocolaptes picumnus, D. certhia, and Dendrocincla merula to medium-sized Dendrocincla fuliginosa). Four other regular ant-followers occur in the region but were not found at the study areas. Forty-five species of casual or nonprofessional ant-followers, including 16 antbirds, 5 woodcreepers, and 5 manakins, also were recorded. Percnostola rufifrons tends to be at the forest edge or in second growth. Pithys albifrons works around Gymnopithys rufigula, Hylophylax poecilonota peripheral to both, in the forest interior. The large Dendrocolaptes picumnus and medium-large Dendrocincla merula often capture prey near the ground, like antbirds. Unlike antbirds, which use vertical or horizontal slender perches, the woodcreepers use thick vertical perches. Dendrocolaptes certhia and Dendrocincla fuliginosa also tend to capture prey high over the ground-foraging antbirds. The woodcreepers tend to forage lower at midday. Hylexetastes perrotti is rare, and overlaps strongly with D. picumnus. There is fairly large overlap among the 9 professional ant-followers, and large ones chase away smaller ones. Nonprofessional birds tend to forage briefly or peripherally when or slightly after the professional species are active. They also forage above the antbirds and below or above the woodcreepers, and concentrate at forest edges or in second growth. The guild of ant-following birds in this region differs fairly widely from guilds in Panamá and at Belém, Brazil; the absence of large antbirds and the predominance of large woodcreepers north of the Amazon are the major differences.


2008 ◽  
Vol 38 (10) ◽  
pp. 2616-2625 ◽  
Author(s):  
Raul Rosenvald ◽  
Asko Lõhmus ◽  
Andres Kiviste

Survival of live retention trees is a key issue for stand-scale applications of natural-disturbance-based silviculture. We explored the survival of 3255 trees in 102 cut areas (mean size 2.3 ha) in Estonia for 6 years, focusing on spatial variation and preadaptation of the trees. Altogether, 35% of the trees died during the study period, contributing 4.4 m3 of downed dead trunks and 1 m3 of standing dead trees per hectare. The annual mortality rates declined over time. The main survival determinants were tree species (higher for hardwood deciduous trees), diameter (species dependent), position relative to forest edge (higher for trees near current or former forest edges), retention density (positive), and exposure (negative). The results suggest that (1) green-tree retention can effectively increase the abundance of large shade-tolerant trees, but it is equally important for producing deadwood; (2) larger individuals, former interior-forest trees near current forest edges, and preadapted trees in open conditions should be preferably retained; (3) there is no obvious necessity to modify tree-retention techniques for tree survival according to geographical region or forest site type.


THE BULLETIN ◽  
2020 ◽  
Vol 5 (387) ◽  
pp. 56-64
Author(s):  
G.J. Sultangazina ◽  
◽  
А.N. Kuprijanov ◽  
О.А. Kuprijanov ◽  
R.S. Beyshov ◽  
...  

The current article presents study results made on the coenoflora of Adonis vernalis L. in Northern Kazakhstan. The materials have been gathered in the course of field research taking into account the literary data. Ontogenesis and age structure of the coenopopulations are provided on the basis of detailed-route studies. The study of age-related stages was carried out on the territory of Northern Kazakhstan (Akmola and North Kazakhstan regions) in 2018-2019. A. vernalis is a short-stem grassy polycarpic plant, it is represented in Northern Kazakhstan by the populations of dry meadows (Kokshetau Upland) and real meadows (the forest-steppe of North Kazakhstan region). Ontogenesis of A. vernalis has three periods and 7 age stages. Plants have low seed productivity. Seeds have a long endogenous peace related to the underdevelopment of a seed germ. A characteristic feature is the presence of a long pregenerative period in plants of the "steppe" type coenopopulations and its reduction in the "meadow" type coenopopulations. There have been studied thirteen coenopopulations of A. vernalis located in Akmola and North Kazakhstan regions. Coenopopulations of A. vernalis are bound to four main habitats: forest edges, meadow steppes, meadows, artificial plantations. By age, young populations are formed on forest edges, and according to the "delta - omega" classification, there are mature coenopopulations. Mature coenopopulations are mostly formed in meadow steppes, but according to the "delta - omega" classification, all coenopopulations are aging. On meadows, there are many young coenopopulations, but according to the "delta - omega" classification, they are all mature. In artificial plantings, the majority of coenopopulations are aging, but according to the "delta - omega" classification, they are all mature. Thus, changes in habitual living conditions lead to the aging of A. vernalis coenopopulations. By density (pcs/100 m2) all populations are divided into three groups: high, medium, low. All forest edge coenopopulations have a high density, in meadow steppes, the density is average, on meadows and in artificial plantings it is low. The recovery index in most coenopopulations is less than one which indicates a low recovery in A. vernalis populations. The range of age stages shows that in most coenopopulations they are normal, the exception is CP-5 (among artificial plantings) which indicates an old stage of the population and possibly its soon elimination.


The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 595-600 ◽  
Author(s):  
D. Ryan Norris ◽  
Bridget J. M. Stutchbury ◽  
Trevor E. Pitcher

Abstract We tested whether Hooded Warblers (Wilsonia citrina) avoided abrupt forest edges by radiotracking males breeding in small, isolated forest patches (0.5–2.0 ha) in northwest Pennsylvania. Because territory edges were synonymous with abrupt forest edges in all cases, we compared space use patterns with males radiotracked in a nearby continuous forest (150 ha), where we defined edge from territorial boundaries. Based on the proportion of edge to core area, males in both habitats avoided the area within 20 m of the edge, implying that males responded to the presence of territory edge rather than forest edge. Surprisingly, however, males in isolated fragments used the edge area significantly more than males in continuous forest, even when measured against the relative amount of edge area within each territory. Elevated levels of edge use were not related to distance of nests to edges, nest stage, or time of day. We conclude that the presence of physical edges is not the sole determinant of territorial space use in this species and there are likely additional social factors influencing occupancy rates in small, isolated woodlots. Therefore, definitions of forest-interior species based on edge use need to be reconsidered.


1996 ◽  
Vol 20 (3) ◽  
pp. 292-310 ◽  
Author(s):  
Arthur W. L. Veen ◽  
Wim Klaassen ◽  
Bart Kruijt ◽  
Ronald W.A. Hutjes

Although the soil-vegetation-atmosphere exchange of momentum and heat is fairly well understood for many types of homogeneous surfaces, the disturbances created by tran sitions of one surface type to another remain to be analysed more fully. This is especially true for the impact which a large transition such as the forest edge has on the average fluxes in a small-scale heterogeneous landscape with forest. Recently acquired experimental evidence appears to some extent contradictory and at variance with conventional concepts.


Author(s):  
Osman Topaçoğlu ◽  
Emre Genç

Forest edges created by silvicultural treatment influence micro-climatic conditions and available light in forest stands. Studies regarding the impacts of forest edges on regeneration is limited in mixed Oriental beech (Fagus orientalis Lipsky)-Scots pine (Pinus sylvestris L.) stands. In this study, the influences of forest edges on height growth, root-collar diameter (RCD) growth and density of seedlings in an adjacent stand of Oriental beech-Scots pine were observed. In addition, the effects of stand basal area and height-to-crown base (HCB) on height growth, RCD growth and seedlings density were monitored. The study was conducted within Samatlar Forest Planning Directorate, in Kastamonu city, Turkey. In the selected Oriental beech-Scots pine stand, twenty-five transects were installed perpendicular to the forest edge, and all the measurements were taken within these transects. There were statistically significant relationships between the distance from the forest edge and the growth of Scots pine seedlings (p<0.05), while the stand edge did not have any effect on the growth of Oriental beech seedlings. Density of Scots pine seedlings decreased, while Oriental beech seedling density increased from the edge into the intact stand (p<0.05). Stand basal area and HCB did not significantly change from the edge into the intact stand (p>0.05). The differences in seedling growth and seedling density between the two species can be associated with their dissimilar tolerance to shade. The initial results obtained in this study point out the importance of forest edges on the regeneration of Oriental beech and Scots pine seedlings. Data suggest that regeneration of mixed Oriental beech-Scots pine should be successful using group methods rather than traditional shelterwood method within entire stand.


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