Birds Effect Video Download Free Fire

A fire management strategy of deliberate patch-mosaic burning (PMB) is postulated to promote biodiversity by providing a range of habitat patches with different fire histories, habitat qualities, and vegetation ages at a given scale. We investigated the response of avian fauna to fire, particularly species richness and community composition, in a landscape composed of a diversity of vegetation ages including long-unburned refuges (age 26 years), compared with a landscape of uniform vegetation ages recovering from an extensive and intense fire.

There was no effect of heterogeneity in vegetation age on species richness at whole forest management block (about 6000 ha), or local (2 ha) scales. There were different responses of particular species to vegetation age. Nine species showed responses to vegetation age at local (2 ha) scales, which is presumably a surrogate for availability of key resources and which changes over time. Australian Pipit (Anthus australis Vieillot, 1818) were absent from swamp vegetation

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Mosaics of different vegetation ages had no net benefit for biodiversity, as measured by species richness and assemblage composition, at the forest block management unit scale. Different responses to vegetation age among bird species did not lead to increased bird richness at the scale of forest management block. A potential advantage of mosaics in conservation of avian biodiversity is through preservation of patches of older vegetation ages in the landscape, compared to the periodic extensive loss of older vegetation ages in wildfires. However, the absence of large-scale effects of vegetation age on bird species richness, the tendency for birds to specialize to fuel ages >5.5 years in the landscape studied, and indications of flexible responses of some species at landscape scales allows some flexibility in fuel management strategies and the scale at which they are applied with respect to avifauna.

A goal of managers of fire in biological conservation areas is to maintain the capacity of managed units of land to sustain biodiversity and to minimize the extinction risk of individual species (Department of Parks and Wildlife 2017). A fire management strategy of deliberate patch-mosaic burning (PMB) was postulated to promote biodiversity by providing a range of habitat patches with different fire histories, habitat qualities, and seral stages at a given scale (Parr and Andersen 2006; Burrows 2008).

In general terms, the responses of bird species to fire are to severity and extent of fire (Barton et al. 2014; Lindenmayer et al. 2014; Berry et al. 2015b); the timing of fire in relation to vegetation succession, and structural and floral maturation processes (Pons and Clavero 2010; Watson et al. 2012b; Chalmandrier et al. 2013); and the spatial arrangement and contrast of vegetation ages in landscapes (Sitters et al. 2015; Sitters et al. 2016). Thus, the passage of time and recurrence of fire render mosaics of different vegetation ages as dynamic entities, and species diversity and community composition responses to them are also likely to be dynamic (e.g., Tingley et al. 2016).

The premise that mosaics of vegetation ages might lessen the extent and severity of unplanned fires while promoting biodiversity prompted the Department of Conservation and Land Management in Western Australia to investigate the feasibility of employing frequent applications of fire to construct a fine-scale, vegetation age mosaic across an entire forest block of several thousand hectares, and to examine effects on particular taxa, including avifauna (Burrows and Wardell-Johnson 2004).

This study investigated the response of avian fauna to fire, particularly species richness and community composition, in a landscape composed of a diversity of vegetation ages, including vegetation ages from unburned patches to 26 years, compared with one of extensive uniform vegetation ages (ages 1.5 and 9.5 years) recovering from an intense fire. We considered variation in species richness and community composition with time since last fire, and across land systems that are surrogates for broad vegetation units (Mattiske and Havel 1998, 2000). We tested the hypotheses that: (1) individual bird species are more common in particular post-fire vegetation ages; and (2) a fine-grain vegetation age mosaic induced by frequent introduction of fire under mild conditions offers an advantage, in terms of maintenance of, or increase in, species richness, over a vegetation age succession initiated by a single extensive fire event. We considered the effects of the different fire regimes on local species richness at 2-hectare sample points, as well as species richness at the scale of forest blocks across ~6000 ha. We considered the implications of responses of individual bird species, feeding and nesting guilds, species richness, and assemblage composition to vegetation age and heterogeneity in vegetation age with respect to fire planning and management.

The study was conceived as a repeated measures factorial design of two forest blocks (subjected to different fire regimes) by three vegetation units by two replicates of sample points, which were sampled in 2004, 2008, and 2012. In 2008, sampling was completed only in one forest block, leading to incomplete replication over time and compromising the original design. The landscape was sampled with a stratified random design with repeated measures. Sample grids were stratified by forest block and vegetation unit, but there was a random element of placement within vegetation units. Our goals were to test for forest block, vegetation unit, and temporal effects on local (~2 ha) species richness, assemblage composition, and feeding-guild composition. In addition, we wished to document changes in species richness at the forest-block scale (6000 ha) over time.

Surprise and London forest blocks differed in the fire regimes imposed on them. London block, an area of ~5000 ha, was burned prior to the study by a low-intensity fire in spring 1997. Further fire was introduced into London block: prescribed fire in spring 2002, wildfire in summer 2003, prescribed fire in autumn 2005, prescribed fire in autumn 2006, and prescribed fire in spring 2008. Introducing these fires was an attempt to create a fine-scale mosaic of small patches of vegetation at different ages since last fire (seral, or growth stages). By 2012, there were patches of vegetation from a few to several hundred hectares ranging from relatively recently burned to long unburned (Burrows and Middleton 2016). Heterogeneity in vegetation ages occurred at scales within sample points (meters to tens of meters) and between sample points (hundreds of meters to kilometers) (Table 1). Surprise forest block (~6700 ha), which adjoins London forest block to the north, was burned in one single fire event by an intense wildfire in March 2003 (Wittkuhn and Hamilton 2010). Forest blocks to the west, north, and east were consumed in the same fire. The 2003 fire was intense enough to cause spalling of exposed granite and complete combustion of crown foliage.

A network consisting of 12 permanently marked sample points was established in 2004 in the three major land systems described above in both London (six sample points, two replicates of each vegetation unit) and Surprise West forest blocks (six sample points, two replicates of each vegetation unit) (Table 1). The six points on London were sampled in 2008 and 2012. No sample points were sampled in Surprise West in 2008, but sample points in Surprise West were sampled in 2012 (Table 1). Later than 2014, other planned fire treatment overlaid the mosaic of ages on London forest block, ending the process of maintaining the fine-grain mosaic.

At least some species were expected to be more common in particular vegetation ages after fire. To determine vegetation age effects, we compared abundance of each species per sample point when paired observations within sample points from youngest vegetation (age 5.5 years) were available from 2004, 2008, and 2012 data. Differences in raw abundance were tested with Wilcoxon paired-sample tests (Sokal and Rohlf 1981). Potential patch size and edge effects were unavoidable due to the necessity to combine London and Surprise West data for all vegetation units to provide a sufficient number of pairs. Using the same data, we identified species with exclusive vegetation unit preferences (Caldyanup or forest) and tested for age preferences using occurrence of samples that encountered particular species. We constructed contingency (2 2) tables describing numbers of samples by presence and absence, and in each of the youngest vegetation age (5.5 years) class and tested for independence between vegetation age and occurrence using Fisher Exact tests (Sokal and Rohlf 1981).

Different species have different ecological requirements in terms of what they feed upon, where they feed, and where they nest. Different ecological requirements might be expected at different vegetation ages after fire. To determine the association between ecological requirements and vegetation ages after fire, we derived feeding and nesting strategies for each species from Abbott (1999) and Birdlife Australia (2018). Feeding strategies considered were: omnivore, carrion scavenger, vertebrate predator, insectivore general, insectivore ground, insectivore foliage, insectivore trunk or bark, insectivore aerial, nectar feeder, fruit eater, seed eater, and cambium feeder. Many species have multiple feeding strategies. Nesting location categories were: ground, understory, mid story, and overstory.

For each species we calculated the log10-transformed abundances in each sample and calculated mean difference between pairs of observations taken 1.5 and 9.5 years after fire. We calculated mean differences using only pairs of data for which the species were observed in one or both samples of the pair. We used the means to assign species as increasing in abundance, or decreasing in abundance between 1.5 and 9.5 years after fire. We tested for independence between apparent vegetation age preferences and feeding strategies, and apparent age preferences and nesting strategies, using Fisher Exact tests on numbers of species in categories in a similar manner to that described above. We confined comparisons to the Surprise West sample points to avoid potential patch size effects inherent in the London mosaic sample points. 17dc91bb1f