The effect of fire on birds of mulga woodland in arid central Australia

2010 ◽  
Vol 19 (7) ◽  
pp. 949 ◽  
Author(s):  
Adam J. Leavesley ◽  
Geoffrey J. Cary ◽  
Glenn P. Edwards ◽  
A. Malcolm Gill

The principal ecosystem driver in arid Australia is unpredictable rainfall, but it is hypothesised that fire also plays an important role in determining the distribution of animals. We investigated the effect of fire on birds in mulga (Acacia aneura) woodland in the central Australian arid zone. The study was conducted at Uluru–Kata Tjuta National Park using 63 sites classified into one of three time-since-fire classes: burnt 2002; burnt 1976; and long-unburnt. Birds were sampled in the winter and spring of 2005 and 2006 and vegetation structure was measured at all sites. Vegetation structure varied with time-since-fire. The burnt 2002 treatment was an early seral stage of mulga woodland and effectively a grassland. The burnt 1976 and long-unburnt treatments were both woodland, but the long-unburnt treatment had greater canopy cover and height. The bird community in the burnt 2002 treatment was characterised by granivores, whereas that in the burnt 1976 and long-unburnt treatments was characterised by foliar insectivores. All species showed monotonic responses to time-since-fire (i.e. none were at significantly highest density in the burnt 1976 treatment). Fire in mulga woodland changed the vegetation structure and consequently also changed the composition of the bird communities.

2019 ◽  
Vol 30 (1) ◽  
pp. 1-20 ◽  
Author(s):  
MIA A. DERHÉ ◽  
DEO TUYISINGIZE ◽  
WINNIE ECKARDT ◽  
FAIDA EMMANUEL ◽  
TARA STOINSKI

SummaryThe Volcanoes National Park (VNP) in Rwanda, part of the Virunga massif in the Albertine Rift region, boasts some of Rwanda’s best remaining natural vegetation and is home to many endangered and endemic species. The park has suffered from high levels of degradation and destruction, reducing in size by 50% during the 1960s and 1970s, and remains under threat from illegal activities, human population pressure and climate change. This study is the first to investigate the status and trends of bird communities in the VNP, using a multi-year dataset. We use a five-year dataset, totalling over 3,200 point-counts, both within and around the VNP, to assess the conservation value of the VNP for birds in comparison with other national parks and non-protected areas. We assess bird communities and population trends within and around the parks and identify important habitat factors for birds within the VNP. We found that the VNP hosts a unique bird community compared to other localities, with several Albertine Rift endemics and threatened species occurring in the VNP. Hagenia/ Hypericum woodland, herbaceous vegetation, brush ridge and mixed forest host the highest levels of bird diversity in the VNP, whilst the park’s waterbodies provide key habitat for the endangered Albertine Rift endemic Grauer’s Swamp-warbler (Bradypterus graueri). Elevation had a negative effect on bird diversity in the VNP, whilst the basal area of dead trees, Hagenia and vines had a positive effect. Both inside and outside the VNP, there was a significant decline in abundance and species richness over the sampling years; however, we advocate for further monitoring to confirm these trends. Based on our findings, we recommend effective, targeted management of key habitats for birds within the park, including those identified in this study, in order to mitigate bird declines and conserve the unique bird communities in the VNP.


2013 ◽  
Vol 19 (1) ◽  
pp. 28 ◽  
Author(s):  
Adam J Leavesley ◽  
Geofferey J Cary

It is often assumed that a fine-scaled mosaic of different times-since-fire supports greater biodiversity than a coarsescaled mosaic — the fire mosaic hypothesis. A potential mechanism of the fire mosaic hypothesis is the effect of area on species diversity. We investigated the effect of patch area on bird communities in mulga (Acacia aneura) woodland in central Australia. The study was conducted at Uluru Kata-Tjuta National Park using 55 fixed-area sites classified to the time since last fire: burnt 2002; burnt 1976 and long unburnt. Birds were surveyed in the winter and spring of 2005 and 2006. Of 20 key species, two showed a positive density-area effect (i.e. higher density in larger patches). Patch area did not affect total bird density or species richness. However, species turnover (ß-diversity) was greater in large patches in the burnt 2002 treatment than it was in small patches. There was no effect of patch area on the composition of the bird communities in any of the time-since-fire classes. We concluded that patch area did affect the distribution of some birds in mulga woodland. However, patch area was not a mechanism of the fire mosaic hypothesis because the effects of patch size tended to increase avian diversity in larger patches rather than small.


2017 ◽  
Vol 7 (2) ◽  
pp. 1
Author(s):  
Molla Mekonnen Alemu

Nech Sar National Park hosts a variety of unique terrestrial and aquatic features. The ground water forest of the park is characterized by dense canopy cover, evergreen, none rainfall dependent out of its biome region, rich in ground water and associated wetlands and mixed shrub land vegetation structure. Since ecosystem management is solidly dependent on localized factors, the research was carried out to explore the regeneration status of the ground water woody vegetation of Nech Sar National Park as it is a crucial element of identifying environmental as well as human induced factors that are affecting the restoration potentials of the vegetation. A total of 36 experimental plots were employed along five different transects that were laid out systematically so as to explore the regeneration status of the major woody tree species of the ground water vegetation of the park. The findings showed that, the ground water vegetation is at high risk of natural regeneration that needs the urgent interference of all concerned Government and development partners in averting the selective cutting of trees so as to meet the ever increasing household energy demand of Arba Minch city.


2015 ◽  
Vol 21 (1) ◽  
pp. 74 ◽  
Author(s):  
Judy E. Smith

Environmental variables influence the dynamics of bird communities. Australian arid-adapted bird communities must cope with particularly high levels of spatial and temporal variability, including inevitable but unpredictable periods of drought. Over four years, which included a severe drought and a period of above-average rainfall, I quantified the responses of a bird community in arid north-western New South Wales to regular seasonal and irregular climatic variation, especially rainfall, as well as spatial variation. I found pronounced changes in the abundance and composition of the avifauna that related to drought and, to a lesser extent, seasonal variability. Overall bird abundance and species richness declined during the drought but the magnitude and direction of population fluctuations of resident, nomadic and migratory species, different feeding groups, and individual species were not consistent. Avian densities and species richness in the study area were higher in mesic habitats associated with drainage lines than in run-off areas. The study demonstrated the importance of local habitat heterogeneity. The asynchronous species responses to a fluctuating environment indicated that drought is likely to have a differential effect on resources and that individual species respond differently to environmental variability. Effective land management and conservation of Australian arid-adapted bird communities requires an understanding of their spatial and temporal variability and dynamics at both local and regional level. A proper understanding of the variability and dynamics of the avifauna is especially important as climate change is predicted to exacerbate the climatic variability and unpredictability of the arid zone in future years.


2007 ◽  
Vol 34 (5) ◽  
pp. 359 ◽  
Author(s):  
Christine A. Schlesinger

Pitfall traps are commonly used to capture terrestrial vertebrates, but it is not known whether differences in vegetation structure affect the efficiency of these traps. Studies that investigate the effects of fire, grazing or vegetation rehabilitation on faunal populations usually compare sites that differ in vegetation structure and the validity of using pitfall traps to sample populations under these circumstances is open to question. This study tests whether vegetation structure affects the rate at which lizards are captured in pitfall traps by cutting ground vegetation in a controlled experiment conducted in field enclosures. The study was undertaken in an area of mulga (Acacia aneura) shrubland in central Australia. Ground cover, consisting of grasses and forbs, was reduced from ~27% to 10% in treatment enclosures. These levels of cover correspond broadly to the range of ground covers encountered in this habitat, including areas with high and low levels of grazing. No difference was detected in the rate at which lizards were captured in enclosures where grass was cut compared with the control enclosures or rates of capture before grass was cut. These results indicate that pitfall trapping is a valid technique for comparing lizard populations in arid mulga shrublands within the range of vegetation covers used in this study, including areas that are subject to different levels of grazing.


2018 ◽  
Vol 30 (1) ◽  
pp. 173-193 ◽  
Author(s):  
Yeongjun Cho ◽  
Hasong Kim ◽  
Hyeonho Myeong ◽  
Jungwon Park ◽  
Janggeun Oh

2021 ◽  
Vol 13 (2) ◽  
pp. 257 ◽  
Author(s):  
Shaun R. Levick ◽  
Tim Whiteside ◽  
David A. Loewensteiner ◽  
Mitchel Rudge ◽  
Renee Bartolo

Savanna ecosystems are challenging to map and monitor as their vegetation is highly dynamic in space and time. Understanding the structural diversity and biomass distribution of savanna vegetation requires high-resolution measurements over large areas and at regular time intervals. These requirements cannot currently be met through field-based inventories nor spaceborne satellite remote sensing alone. UAV-based remote sensing offers potential as an intermediate scaling tool, providing acquisition flexibility and cost-effectiveness. Yet despite the increased availability of lightweight LiDAR payloads, the suitability of UAV-based LiDAR for mapping and monitoring savanna 3D vegetation structure is not well established. We mapped a 1 ha savanna plot with terrestrial-, mobile- and UAV-based laser scanning (TLS, MLS, and ULS), in conjunction with a traditional field-based inventory (n = 572 stems > 0.03 m). We treated the TLS dataset as the gold standard against which we evaluated the degree of complementarity and divergence of structural metrics from MLS and ULS. Sensitivity analysis showed that MLS and ULS canopy height models (CHMs) did not differ significantly from TLS-derived models at spatial resolutions greater than 2 m and 4 m respectively. Statistical comparison of the resulting point clouds showed minor over- and under-estimation of woody canopy cover by MLS and ULS, respectively. Individual stem locations and DBH measurements from the field inventory were well replicated by the TLS survey (R2 = 0.89, RMSE = 0.024 m), which estimated above-ground woody biomass to be 7% greater than field-inventory estimates (44.21 Mg ha−1 vs 41.08 Mg ha−1). Stem DBH could not be reliably estimated directly from the MLS or ULS, nor indirectly through allometric scaling with crown attributes (R2 = 0.36, RMSE = 0.075 m). MLS and ULS show strong potential for providing rapid and larger area capture of savanna vegetation structure at resolutions suitable for many ecological investigations; however, our results underscore the necessity of nesting TLS sampling within these surveys to quantify uncertainty. Complementing large area MLS and ULS surveys with TLS sampling will expand our options for the calibration and validation of multiple spaceborne LiDAR, SAR, and optical missions.


Author(s):  
Emilia Grzędzicka ◽  
Jiří Reif

AbstractPlant invasions alter bird community composition worldwide, but the underlying mechanisms still require exploration. The investigation of feeding guild structure of bird communities can be informative in respect to the potential impact of invasion features on the availability of food for birds. For this purpose, we focused on determining the influence of the invasive Sosnowsky’s Hogweed Heracleum sosnowskyi on the abundance of birds from various feeding guilds. In spring and summer 2019, birds were counted three times on 52 pairs of sites (control + Heracleum) in southern Poland, at various stages of Sosnowsky’s Hogweed development (i.e. sprouting, full growth and flowering, all corresponding to respective bird counts). We have shown that the presence of invader negatively affected the abundance of birds from all feeding guilds. However, a closer examination of the invaded sites uncovered that responses of particular guilds differed in respect to development stages expressed by a set of characteristics of the invader. Ground and herb insectivores were more common on plots with a higher number of the invader, while the abundance of bush and tree insectivores was negatively correlated with hogweeds’ height. Granivores were not affected by the invader’s features, while the abundance of omnivores was negatively related to the number of flowering hogweeds. Besides showing the general negative impact of the invader on different feeding guilds, our research has shown that certain aspects of Sosnowsky’s Hogweed invasion may support or depress occurrence of different birds on invaded plots. Knowledge of these aspects may facilitate our capacity for coping with challenges the invasive plants put in front of bird conservationists.


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