Does adjacent land use affect predation of artificial shrub-nests near eucalypt forest edges?

2002 ◽  
Vol 29 (2) ◽  
pp. 127 ◽  
Author(s):  
S. Piper ◽  
C. P. Catterall ◽  
M. F. Olsen

Edge-related increases in nest-predation levels were tested using artificial nests placed within eucalypt forest remnants at distances of 0, 60, and 235 m from edges adjacent to areas of urban, pasture, and Pinus plantation. There were eight replicate sites of each edge type, scattered widely across a 30 000-km2 study region. Open-cup nests containing one quail egg and two plasticine eggs were placed in shrubs and exposed for 6 days. When predation of the quail egg was used to calculate predation levels, predation varied significantly with edge type but not distance to the edge, due to relatively low levels within sites bordering Pinus plantations. When predation of any egg was used to calculate predation levels, predation was not significantly affected by edge type or distance to the edge. Predation levels within eight independent forest interior transects distributed across the study region, and located 500-800 m from the nearest edge, were similar to those within transects 0 m from edges. Birds were the most important class of predator within all combinations of site type and distance to edge, and accounted for 92% of identified predation overall. These results do not support the existence of edge-related increases in predation of shrub nests within subtropical eucalypt forests.

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.


2007 ◽  
Vol 121 (2) ◽  
pp. 150
Author(s):  
Vanessa B. Harriman ◽  
Justin A. Pitt ◽  
Serge Larivière

Ground-nesting birds typically experience high predation rates on their nests, often by mammalian predators. As such, researchers and wildlife managers have employed numerous techniques to mitigate nest predation. We investigated the use of scents as repellents to deter predators from both artificial and natural ground nests. Survival rates of artificial nests did not differ among six groups of substances (Wald ?2 df = 5 = 4.53, P < 0.48); however the chronology of predation among groups differed. A commercial Coyote urine based deterrent (DEER-D-TERTM), human hair, and Worcestershire sauce were depredated faster than the control (F4,5 = 40.3, P < 0.001). Nest survival of natural nests differed among those groups tested (Wald ?2 df = 2 = 11.8, P < 0.005); the eight mothball treatment decreased survival (Wald ?2 df = 1 = 11.5, P < 0.005), which indicated that novel smells may attract predators or result in duck nest abandonment when coupled with natural duck scent. Chronologies of predation events among treatment groups were not different for natural nests (F2,3 = 1.9, P = 0.22). These findings indicate an interaction between novel scents and predator olfactory cues.


1999 ◽  
Vol 77 (7) ◽  
pp. 1170-1173 ◽  
Author(s):  
Keith P Lewis ◽  
William A Montevecchi

In artificial-nest studies, Japanese Quail (Coturnix japonica) eggs have been used as surrogates for passerine eggs, although small mammals that prey on passerine eggs may be unable to consume Japanese Quail eggs. To determine the influence of egg size on nest predation in different landscapes on insular Newfoundland, we placed either a Japanese Quail egg or a smaller Chinese Painted Quail (Xexcalfactoris chinensis) egg in artificial ground nests along lakeshore forest edges and along riparian buffer strips. Clay eggs were used to identify nest predators. Levels of predation on nests with Japanese Quail and Chinese Painted Quail eggs were similar. Based on clay eggs, predation was attributed to red squirrels (Tamiasciurus hudsonicus), and we found no evidence that smaller mammals preyed on artificial nests. We conclude that the Japanese Quail egg is acceptable for use in artificial-nest studies in Newfoundland, and we discuss the implications of egg size and small mammals in nest-predation experiments.


Author(s):  
JS Gould ◽  
WL McCaw ◽  
NP Cheney ◽  
PF Ellis ◽  
IK Knight ◽  
...  

Project Vesta was a comprehensive research project to investigate the behaviour and spread of high-intensity bushfires in dry eucalypt forests with different fuel ages and understorey vegetation structures. The project was designed to quantify age-related changes in fuel attributes and fire behaviour in dry eucalypt forests typical of southern Australia. The four main scientific aims of Project Vesta were: To quantify the changes in the behaviour of fire in dry eucalypt forest as fuel develops with age (i.e. time since fire); To characterise wind speed profiles in forest with different overstorey and understorey vegetation structure in relation to fire behaviour; To develop new algorithms describing the relationship between fire spread and wind speed, and fire spread and fuel characteristics including load, structure and height; and to develop a National Fire Behaviour Prediction System for dry eucalypt forests. These aims have been addressed through a program of experimental burning and associated studies at two sites in the south-west of Western Australia.


1994 ◽  
Vol 42 (4) ◽  
pp. 383 ◽  
Author(s):  
JE Hickey

About 20% of Tasmania's wet eucalypt forest is mixed forest, i.e. having a rainforest understorey and a eucalypt overstorey. While one-third of the mixed forest is formally reserved, much of the remainder is subject to logging on an 80-100 year rotation which is insufficient for the redevelopment of mature mixed forest. The routine silvicultural regeneration treatment for wet eucalypt forests is to clearfell, burn and sow with eucalypt seed. A comparison of the Vascular floristics of 20-30-year-old silvicultural and wildfire regeneration with oldgrowth mixed forest showed that most species common in oldgrowth mixed forest were represented in approximately similar frequencies in silvicultural regeneration and wildfire regeneration. The major floristic difference between the two regeneration types was the much lower frequency of oldgrowth epiphytic fern species in silvicultural regeneration and a higher frequency of a sedge species often associated with disturbed areas. However, after a single logging treatment, the vascular plant floristics of silvicultural regeneration were sufficiently similar to wildfire regeneration to assume that, in the absence of further logging or fires, the silvicultural regeneration could become mature mixed forest and eventually rainforest. Further work is required to determine whether regrowth mixed forest can be logged at 80-100 years and still retain sufficient rainforest elements to eventually return to mixed forest within the life span of the dominant eucalypts. The critical factor in the silvicultural perpetuation of mixed forest may be rotation length rather than regeneration treatment.


2005 ◽  
Vol 32 (4) ◽  
pp. 320-325 ◽  
Author(s):  
HOLLY P. JONES ◽  
R. WILLIAMHENRY ◽  
GREGG R. HOWALD ◽  
BERNIE R. TERSHY ◽  
DONALD A. CROLL

Introduced rats depredate every life stage of island nesting seabirds, but the extent of predation is rarely quantified. Introduced black rat (Rattus rattus) and native deer mouse (Peromyscus maniculatus anacapae) predation on Xantus's murrelet (Synthliboramphus hypoleucus scrippsi) nests was experimentally quantified using artificial nests before and after rat eradication on Anacapa Island (California). The staged rat eradication programme provided experimental treatments: in 2002 rats were eradicated on one island (East Anacapa Islet) and remained on two islands (Middle and West Anacapa Islets), providing a control comparison, and, in 2003, rats were eradicated from the remaining islands (Middle and West Anacapa Islets). In 2002, 96% of artificial nests were depredated on control islands (rats present) with rats accounting for most predation. Nest predation on the treatment island (rats eradicated) in 2002 was significantly lower: 8% of artificial nests were depredated, mostly by endemic deer mice. In 2003, following rat eradication on the remaining islands (Middle and West Anacapa Islets), nest predation was reduced from 96% in 2002 to 3% of total nests in 2003. Predation of nests on East Anacapa Islet (rats eradicated in 2002) increased significantly due to reintroduction and recovery of native deer mouse populations, with 23% of artificial nests depredated. The inference is that rat predation on real Xantus's murrelet nests was responsible for the historically low nesting success and small population sizes of breeding murrelets on Anacapa Island. With rats removed, the hatching success of Xantus's murrelet chicks and the number of individuals nesting on Anacapa Island will increase dramatically. Artificial nest studies are particularly well suited to quantifying introduced rat impacts on hole and crevice nesting seabirds and can simultaneously serve as an effective monitoring tool to detect the presence of rats and the recovery of native nest predators.


2017 ◽  
Vol 44 (7) ◽  
pp. 471
Author(s):  
Vic Jurskis

Assessments of the conservation status of koalas and trends in their population have been based on mostly unstated false assumptions about their pre-European status and on notions that either they were naturally regulated by their predators, chiefly Aborigines and dingoes, or that they somehow ‘self-regulated’ their fecundity. Closer examination of their ecological history suggests that frequent mild burning by Aborigines maintained eucalypt forests having fewer, mostly healthy trees, fewer young trees, canopies comprising mostly hard and dry leaves with low nutrient content, and, consequently, very few koalas. European explorers did not see them because they were solitary animals occupying large home ranges. After burning was disrupted, koalas responded to increased food resources in dense new growth of eucalypts and in stressed trees continually turning over new foliage. An export skin industry flourished. When their food resources were depleted by clearing or ringbarking of new growth and/or death of declining stands during droughts, koalas crashed back to low levels. Koalas continue to irrupt and decline through much of their range according to changing land management. Wildlife managers should re-assess their status and their management from a clear historical and ecological perspective.


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