Penetration of remnant edges by noisy miners (Manorina melanocephala) and implications for habitat restoration

2007 ◽  
Vol 34 (4) ◽  
pp. 253 ◽  
Author(s):  
Michael F. Clarke ◽  
Joanne M. Oldland

The noisy miner (Manorina melanocephala) is a large, communally breeding colonial native honeyeater renowned for aggressively excluding virtually all other bird species from areas they occupy. In the woodlands of southern and eastern Australia, numerous studies have identified the domination of remnants by noisy miners as having a profound negative effect on woodland bird communities. Despite this, very little is known about the habitat characteristics that make domination of a site by noisy miners more likely. This study investigated the depth from edges that noisy miners penetrated into large woodland remnants (>48 ha) within Victoria and attempted to identify habitat characteristics that influenced the depth to which they penetrated. Penetration depth differed significantly across four broad habitat types but commonly ranged from 150 m to more than 300 m from the remnant edge. If noisy miners colonise a site, their capacity to penetrate in from a remnant edge has implications for the size that remnants need to be (>36 ha) to contain any core ‘noisy-miner-free’ habitat and the width that habitat corridors need to be to avoid domination by noisy miners (>600 m). Broad differences in habitat type and the abundance of noisy miners at a site were the most powerful predictors of penetration distance. The density of canopy trees on a site was the only other habitat variable contributing to the most parsimonious model of penetration depth. Decreasing density of trees was associated with increasing penetration depth by noisy miners.


1997 ◽  
Vol 24 (6) ◽  
pp. 631 ◽  
Author(s):  
Merilyn J. Grey ◽  
Michael F. Clarke ◽  
Richard H. Loyn

It has been postulated that aggressive honeyeaters like the noisy miner, Manorina melanocephala, may contribute to rural tree decline by excluding small insectivorous birds from remnant patches of woodland, thereby reducing the level of predation upon defoliating insects. Previous studies provide correlational evidence that avian diversity and abundance is lower in remnant patches of woodland occupied by noisy miners than in those without noisy miners. Noisy miners were removed from three small remnant patches of woodland in north-eastern Victoria. The removal of the majority of noisy miners from a site, or even the removal of only part of a noisy miner colony from a site, resulted in a major influx of honeyeaters and other insectivorous birds to these sites in the following three months. Such major invasions were not observed on matching control sites. At two of the three removal sites, this led to an increase in both the abundance and diversity of birds on the site. At the third site, there was an increase in the diversity, but not the abundance of birds. These experiments are the first to demonstrate that noisy miners affect avian diversity and abundance by aggressive exclusion of small birds. They also showed that if domination by noisy miners is reduced, small, degraded woodland remnants can support significant populations of some small insectivorous birds and honeyeaters. Noisy miners did not reinvade the experimental sites during the following 16 months and avian diversity and abundance remained higher at the experimental sites than at the paired control sites. Long-term monitoring is needed to determine whether the small invading bird species have a lasting effect upon insect populations and tree health.



1998 ◽  
Vol 4 (1) ◽  
pp. 55 ◽  
Author(s):  
Merilyn J. Grey ◽  
Michael F. Clarke ◽  
Richard H. Loyn

The abundance of an aggressive Australian honeyeater, the Noisy Miner Manorina melanocephala, was reduced at four small (<8 ha) Grey Box Eucalyptus microcarpa woodland remnants by experimental removal. The diversity and abundance of small insectivorous and nectarivorous birds increased at three of the four sites (relative to matching control sites) over the twelve months following the removal of the Noisy Miners. The one exception occurred at a pair of sites where eucalypts began flowering at one site and finished at the other during the Noisy Miner removal period. These results, taken together with those from three earlier experiments where the abundance of Noisy Miners was reduced in Mugga Ironbark E. Sideroxylon woodland remnants, demonstrate that Noisy Miners affect avian diversity and abundance by aggressive exclusion of other species. In five out of seven experiments, Noisy Miners did not reinvade the small woodland remnants during the ensuing twelve months. When Noisy Miner abundance was reduced, increased populations of small insectivorous and nectarivorous birds used small degraded woodland remnants. Colonizing populations of small birds have the potential to reduce insect infestations and may assist in the recovery of dieback-affected woodland remnants. Research is continuing to test this hypothesis. Reducing the abundance of Noisy Miners in remnant eucalypt woodlands may also be a useful, short-term measure, which could assist in the recovery of threatened or endangered bird species.



2021 ◽  
Vol 38 ◽  
pp. 131-136
Author(s):  
A.S. Kutt ◽  
◽  
L. Hales ◽  
P. Hales ◽  
P. Young ◽  
...  

Long-term monitoring of bird communities over time can provide important data for management, and the adaptation of that management over time. We examined data from bird surveys across 37 sites sampled in five different years from 2009 to 2017 in a 56,000-ha tropical savanna conservation reserve, in northern Queensland. Because of the limitations of the survey method and the lack of environmental data for sites, we examined broad patterns in the abundance of small- and large-bodied birds, abundance of Noisy Miners Manorina melanocephala, land type, survey year, and time since last fire. There was some variation in bird species richness and abundance across the land types, years sampled and Noisy Miner abundance; however, the clearest pattern was decreasing numbers of small-bodied birds and increasing Noisy Miner abundance, and an association between time since fire (i.e. <3 years, >5 years), Noisy Miner abundance and diversity in other birds. The apparent and potentially compounding interaction of Noisy Miners and fire could be an emerging problem. Future fire management needs to be embedded in a program of targeted question-driven monitoring and adaptive management, to provide more assured approaches to prescribed burning that enhances bird conservation.



2020 ◽  
Vol 40 (4) ◽  
pp. 529-547
Author(s):  
Michael J. Murphy

The majority of studies into the response of birds to logging in Australian forests has been done in forest-dominated landscapes or relatively large forest blocks, where the surrounding landscape can ameliorate impacts. This is the first study to examine the response of birds to logging of a small, relatively isolated woodland remnant in a landscape dominated by agriculture, with a focus on declining woodland birds. Approximately two thirds of a 120 ha cypress-eucalypt woodland remnant was selectively logged. Eighty bird species in total were recorded 2–3½ years after logging, including 18 recognised as declining woodland birds. Sixty-four species were recorded in the unlogged area and 72 in the logged area. Of the 31 species recorded sufficiently frequently for analysis, 19 showed no statistical difference in occurrence between logged and unlogged areas at the power of the study, nine were more prevalent in unlogged areas and three more prevalent in logged areas. Declining woodland birds comprised 22½% of overall species and 33% of those more prevalent in unlogged areas. Mapping of records enabled the response of a subset of species to be examined in greater detail. Four species illustrate the range of responses by declining woodland birds: Eastern Yellow Robin Eopsaltria australis was confined to unlogged areas, White-browed Babbler Pomatostomus superciliosus favoured unlogged areas, Varied Sittella Daphoenositta chrysoptera favoured proximity to unlogged areas and Red-capped Robin Petroica goodenovii was widely distributed in both logged and unlogged areas. The likelihood of recovery of local woodland bird populations is discussed in the context of limited landscape connectivity and the recent colonisation of the remnant by the hyper-aggressive Noisy Miner Manorina melanocephala. White-browed Babbler and Eastern Yellow Robin are considered to be at high risk of local extinction in the remnant.



2021 ◽  
Vol 28 (4) ◽  
pp. 175-184
Author(s):  
Gergő Erdélyi ◽  
Borbála Szabó ◽  
István Kiss

Sun basking is the most common method for freshwater turtles, such as the European pond turtle, to maintain optimal body temperature. The attributes of the macro- and microhabitat features around the basking sites affect the basking site selection of the European pond turtle. To protect the European pond turtle, it is important to know the basking habits among the biological characteristics of the species, along with the effects of the habitat characteristics and the choice of the type of basking sites. The purpose of our research was to detect the effects of macro- and microhabitat features on the selection of basking sites. We wanted to determine basking site type selection according to the carapace length classes and if there is any difference in the choice of basking trunks and branches with different thicknesses. Turtles choose basking sites with less closed vegetation in their environment. We have detected seasonal differences in the microhabitat features. The closing reed and Typha sp. had a negative effect on the number of observed basking turtles. The most popular type of basking sites in the pond system was the commonly occurred fallen tree trunks and branches in the water, regardless of turtle body size. Most turtles used thinner tree trunks and branches for basking. In the meantime, we found differences in the choice of basking trunks between the turtles with different body sizes. Younger turtles with smaller bodies appeared in larger numbers on emergent branches with smaller diameters.



2021 ◽  
Vol 13 (9) ◽  
pp. 19212-19222
Author(s):  
Bishow Poudel ◽  
Bijaya Neupane ◽  
Rajeev Joshi ◽  
Thakur Silwal ◽  
Nirjala Raut ◽  
...  

There exists limited information on biodiversity including avifaunal diversity and habitat condition in community forests (CF) of Nepal; thus we aimed to fulfill such gaps in Tibrekot CF of Kaski district. We used the point count method for assessing bird diversity and laid out a circular plot size of radius 5-m within 15-m distance from each point count station for recording the biophysical habitat characteristics. Bird species’ diversity, richness and evenness were calculated using popular indexes and General Linear Model (GLM) was used to test the respective effect of various biophysical factors associated with the richness of bird species. In total, 166 (summer 122, winter 125) bird species were recorded in 46 sample plots. The Shannon-Wiener diversity index was calculated as 3.99 and 4.09, Margalef’s richness index as 16.84 and 17.53 and Pielou’s evenness index as 0.83 and 0.84 for summer and winter, respectively. The influencing factors for richness of bird species were season (χ21, 90= 112.21; P= 0.016) with higher richness in the summer season and low vegetation cover (χ21, 89= 113.88; P= 0.0064) with higher richness in lower percentage cover. Thus, community managed forest should be protected as it has a significant role in increasing bird diversity, which has potential for attracting avifaunal tourism for the benefit of the local communities.



2019 ◽  
Author(s):  
Carlos M. Polivka

AbstractConceptual and methodological tools from behavioral ecology can inform studies of habitat quality and their potential for evaluating habitat restoration in conservation efforts is explored here. Such approaches provide mechanistic detail in understanding the relationship between organisms and their habitats and are thus more informative than correlations between density and habitat characteristics. Several Pacific salmon species have been the target of habitat restoration efforts for the past 2-3 decades, but most post-restoration effectiveness studies have been limited to correlative data described above. In mark-recapture assays from four different study years, the affinity of sub-yearling Chinook salmon (Oncorhynchus tschawytscha) and steelhead (O. mykiss) for stream pools restored with or created by engineered log structures was greater than that for pools without restoration, though with high interannual variability. From corresponding distribution and density data, it was clear that habitat affinity data are not always concordant with single observations of density. The same was true of the correlation between either affinity or density and physical characteristics of pools, although depth and current velocity had some explanatory power for both responses in Chinook. Movement into pools by Chinook during the assays indicated that restored pools can support more immigrants at a given density than can unrestored pools; however no such pattern emerged for steelhead. Variation among individuals in body condition has implications for population-wide fitness, and such low variation was correlated with stronger affinity for pools in Chinook regardless of restoration status. This suggests that pools may mediate habitat-related trade-offs and that restoring them might have a positive effect on fitness. Thus affinity, immigration, and condition data give much-needed mechanistic indication of habitat selection for restored habitat via an apparent capacity increase and those potential fitness benefits. This is stronger support for restoration effectiveness than density differences alone because density data 1) may simply indicate redistribution of fish from poor to good habitats and 2) are not adequate to show correlations between restoration and positive change in traits correlated with fitness.



2012 ◽  
Vol 5 (3) ◽  
pp. 36-56 ◽  
Author(s):  
Petr Suvorov ◽  
Jana Svobodová

ABSTRACT Anthropogenic changes in a landscape create new cues for birds, which must permanently adapt to these. If landscape changes occur too quickly, individuals have insufficient time to develop adequate reactions. They may, therefore, preferentially nest in low-quality habitats, which can lead to diminished nesting success and to reduction of their population size. This is usually termed the ecological trap hypothesis. We reviewed 38 studies investigating this phenomenon and analysed whether relationships exist between ecological trap occurrence and geographical region, habitat type, and/or life strategies of bird species. Ecological traps were most often associated with the presence of exotic species. Exotic species can modify environmental conditions in ways to which native communities are not adapted. They have been mainly detected in open habitats. Such open habitats as arable fields and meadows are under greater human pressure, and rapid changes probably occur there more frequently. Although more studies from North America were investigated, the hypothesis was supported more frequently in European studies. This is possibly due to higher human population density and, hence, more frequent habitat changes. Our results show that an ecological trap is not likely associated with migration. Ground nests suffered fewer consequences of such traps than did other nest types. Although the implications of the ecological trap hypothesis in species conservation are undisputable, a more detailed approach is still needed. For instance, some habitat types, such as suburban areas, have been neglected in the context of ecological traps, as has been the phenomenon’s appearance in pristine habitats.



2016 ◽  
Author(s):  
Marie-Andrée Giroux ◽  
Myriam Trottier-Paquet ◽  
Joël Bêty ◽  
Vincent Lamarre ◽  
Nicolas Lecomte

Predation is one of the main factors explaining nesting mortality in most bird species. Birds can avoid nest predation or reduce predation pressure by breeding at higher latitude, showing anti-predator behaviour, and nesting in association with protective species. Plovers actively defend their territory by displaying early warning and aggressive/mobbing behaviour, potentially benefiting the neighbouring nests by decreasing their predation risk. To test for the existence of such a protective effect, we studied the influence of proximity to plover nests on predation risk of artificial nests on Igloolik Island (Nunavut, Canada) in July 2014. We predicted that the predation risk of artificial nests increases and decreases with the distance to and the density of plover nests, respectively. We monitored 18 plover nests and set 35 artificial nests at 30, 50, 100, 200 and 500 m from seven of those plover nests. Surprisingly, we showed that predation risk of artificial nests increases with the density of active plover nests. We also found a significant negative effect of the distance to the nearest active protector nest on predation risk of artificial nests. Understanding how the composition and structure of shorebird communities generate spatial patterns in predation risks represent a key step to better understand the importance of these species of conservation concern in tundra food webs.



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