The effects of vegetation structure on the birds in a tropical savanna woodland in north-eastern Australia

2006 ◽  
Vol 28 (2) ◽  
pp. 139 ◽  
Author(s):  
A. L. Tassicker ◽  
A. S. Kutt ◽  
E. Vanderduys ◽  
S. Mangru
Keyword(s):  
Bird Species ◽  
Canopy Cover ◽  
Aerial Photographs ◽  
Woody Vegetation ◽  
Bird Species Richness ◽  
Widespread Species ◽  
Savanna Woodland ◽  
Bird Richness ◽  
Eastern Australia ◽  
North Eastern

Management of the dynamics of woody vegetation in Australia’s tropical savannas is a vexing issue for both pastoralists and conservation biologists. In savanna regions around the world, increasing density of woody vegetation contributes to declines in pastoral productivity, but its effects on native fauna are largely unknown. In this paper we examine the avifauna in savanna woodlands of varying structure in the Desert Uplands bioregion, Queensland. Vegetation cover maps derived from aerial photographs were used to choose 60 sites, across 4 cattle stations. We sampled sites mapped at 30–45% and 45–60% foliage cover, and areas which previously had these levels of cover but had been mechanically modified, both by broad scale clearing and selective thinning. Between May and June 2004, we measured a range of habitat variables and sampled the birds at each site. Bird species composition varied significantly between treatments. Bird richness and frequency was greatest in intact vegetation. Thirteen species of birds were most frequently encountered in sites with 30–45% canopy cover, compared with 10 species in the 45–60% cover sites, 4 species in the thinned sites and 7 in the cleared sites. Our results suggest that increasing density of woody vegetation in savanna woodland may be to the advantage of some savanna bird species. Mechanical modification to reduce woody vegetation appears to also benefit some common, widespread species, but has a generally negative overall effect on bird species richness.

The woody vegetation communities of the Hluhluwe-Corridor- Umfolozi Game Reserve Complex

Bothalia ◽  
1983 ◽  
Vol 14 (3/4) ◽  
pp. 745-758 ◽  
Author(s):  
A. Whateley ◽  
R. N. Porter
Keyword(s):  
Aerial Photographs ◽  
Woody Vegetation ◽  
Vegetation Communities ◽  
Percentage Frequency ◽  
Riverine Forest ◽  
North Eastern ◽  
Game Reserve ◽  
Canopy Species

Land units for the 900 km- Hluhluwe-Corridor-Umfolozi Game Reserve Complex in north eastern Natal were identified on aerial photographs. The physiognomy, dominants and description of the woody vegetation for each unit were identified during ground inspections and. where necessary, the point-centred quarter method was applied. Two forest, two riverine forest, ten woodland and two thicket communities were recognized. These communities are described according to their distribution, height and percentage frequency of the components in the different canopy strata. A map at a scale of 1:25 000 was also compiled. Some of these communities are compared with other similar woodlands previously described for Natal. In some communities the frequency of certain dominant canopy species in the under tree strata was extremely low and autecological research has been suggested.

scholarly journals THE RELATIVE IMPORTANCE OF THREE SPECIFIC CLIMATIC FACTORS ON NORTH AMERICAN BREEDING BIRD SPECIES RICHNESS

2017 ◽  
Vol XLII-2/W7 ◽  
pp. 1455-1459
Author(s):  
M. Zhang ◽  
Y. Lin
Keyword(s):  
North American ◽  
Climatic Factors ◽  
Potential Evapotranspiration ◽  
Linear Regression Analysis ◽  
Bird Species ◽  
Migratory Species ◽  
Breeding Bird ◽  
Bird Species Richness ◽  
The North ◽  
Bird Richness

Understanding of the relationships between bird species and environment facilitates protecting avian biodiversity and maintaining nature sustaining. However, the effects of many climatic factors on bird richness have not been fully grasped. To fill this gap, this study investigated the relationships between the richness of three typical North American breeding bird species and three climatic factors at the monthly scale. Based on the North American Breeding Bird Survey (BBS) data during 1967–2014, the relationships between the numbers of Carolina wren, Cerulean warbler, and Red-bellied woodpecker and the three climatic factors of precipitation, vapor pressure, and potential evapotranspiration were examined using the method of Pearson linear regression analysis. The results indicated that the three climatic factors have correlations with the richness of the breeding bird species but in different modes, e.g., strong correlations for the non-migratory species but weak correlations for the migratory species.

scholarly journals Chicago’s Urban Cemeteries as Habitat for Cavity-Nesting Birds

2019 ◽  
Vol 11 (12) ◽  
pp. 3258 ◽  
Author(s):  
Alexis D. Smith ◽  
Emily Minor
Keyword(s):  
Tree Species ◽  
Local Level ◽  
Bird Species ◽  
Canopy Cover ◽  
Bird Species Richness ◽  
Individual Bird ◽  
Tree Cavities ◽  
Cavity Nesting ◽  
Naturally Occurring ◽  
Landscape Level

Although not explicitly managed for conservation, urban cemeteries may provide a reserve of dead and dying trees for cavity-nesting birds. However, the ability of urban cemeteries to support these birds on current landscapes is largely unknown. We surveyed cavity-nesting birds and their habitat in 18 cemeteries in Chicago, Illinois (USA). At each location, we examined vegetation, availability of gravestones and monuments for perches, and landscape-level environmental conditions. We tested the importance of these variables for presence of individual bird species, and for overall richness of native cavity-nesting birds. We also assessed the availability and characteristics of tree cavities and their distribution among different tree species. We found that most cemeteries contained at least one dead or dying tree. Across all sampled areas, we detected 207 naturally-occurring and 77 excavated tree cavities. Tree species generally supported cavities in proportion to their abundance. We observed 12 native and two non-native cavity-nesting bird species in the cemeteries. Cavity-nesting bird species richness was best explained by landscape-level variables such as canopy cover and distance to water, but local-level variables (e.g., number of graves in a 50 m radius) influenced habitat selection for some species. Based on our results, we make suggestions for how both existing cemeteries and new “green” cemeteries can support biodiversity conservation.

Lizard diversity on a rainforest - savanna altitude gradient in north-eastern Australia

2011 ◽  
Vol 59 (2) ◽  
pp. 86 ◽  
Author(s):  
A. S. Kutt ◽  
B. L. Bateman ◽  
E. P. Vanderduys
Keyword(s):  
Canopy Cover ◽  
Radiant Heat ◽  
Natural Experiments ◽  
Lizard Species ◽  
Altitudinal Distribution ◽  
Altitude Gradient ◽  
Lower Altitude ◽  
Diverse Range ◽  
Eastern Australia ◽  
North Eastern

Mountain ecosystems act as natural experiments for investigating the relationship between environmental heterogeneity and species diversity. A review of the global altitudinal distribution of reptiles identified a diverse range of patterns driven by climate and taxonomy. No Australian examples were included in this analysis. We addressed this gap by surveying the reptile assemblage along an altitude gradient from upland rainforest (~1000 m) through to open savanna woodlands (~350 m) in north-eastern Australia. Reptiles were sampled on four separate occasions between May 2006 and November 2007. Thirty-six species, representing seven families, were recorded along the gradient. As we used only diurnal active searching, snakes and nocturnal geckoes were probably under-sampled; thus we considered only lizards in the analysis of altitude pattern. Lizard species richness peaked at the mid-altitudes (600–900 m, 11–12 spp.) and abundance highest at the lower (<500 m) and higher (>800 m) zones. This pattern is likely a factor of both the increase in radiant heat sources (reduced canopy cover) and increased species packing due to the diversity of niches available (presence of rock cover and increase in saxicolous species). In the lower-altitude sites the high abundance of few species seems linked to the dominance of disturbance-tolerant species. We conclude that lizard richness and abundance patterns on this transect are not necessarily exhibiting a mid-domain effect, but instead are a function of species-specific ecological and habitat requirements.

scholarly journals Seasonal changes in avian communities living in an extensively used farmland of Western Poland

2016 ◽  
Vol 2 (2) ◽  
pp. 9-18 ◽  
Author(s):  
Zbigniew Kwieciński ◽  
Federico Morelli ◽  
Marcin Antczak ◽  
Martin Hromada ◽  
Paweł Szymański ◽  
...  
Keyword(s):  
Species Richness ◽  
Protected Areas ◽  
Seasonal Changes ◽  
Bird Species ◽  
Bird Communities ◽  
Negative Trend ◽  
Avian Communities ◽  
Farmland Birds ◽  
Bird Species Richness ◽  
Bird Richness

Abstract To study the seasonal changes in avian communities, we collected data in an extensively used farmland in Western Poland during 2006-2013. Generalized additive mixed models were used in order to study the effects of seasonality and protected areas on the overall bird species richness. A similarity percentage analysis was also conducted in order to identify the species that contribute most strongly to dissimilarity among each bird according to the phenological season. Furthermore, the differences in bird communities were investigated applying the decomposition of the species richness in season, trend, and remainder components. Each season showed significant differences in bird species richness (seasonality effect). The effect of the protected areas was slightly positive on the overall species richness for all seasons. However, an overall negative trend was detected for the entire period of eight years. The bird community composition was different among seasons, showing differences in terms of dominant species. Greater differences were found between breeding and wintering seasons, in particular, the spatial pattern of sites with higher bird richness (hotspots) were different between breeding and wintering seasons. Our findings showed a negative trend in bird species richness verified in the Polish farmlands from 2006. This result mirrors the same negative trend already highlighted for Western Europe. The role of protected areas, even if slightly positive, was not enough to mitigate this decline process. Therefore, to effectively protect farmland birds, it is necessary to also consider inter-seasons variation, and for this, we suggest the use of medium-term temporal studies on bird communities’ trends.

Relationships Between Grass, Shrub and Tree Cover on Four Landforms of Semi-Arid Eastern Australia, and Prospects for Change by Burning.

1996 ◽  
Vol 18 (1) ◽  
pp. 104 ◽  
Author(s):  
RL Daly ◽  
KC Hodgkinson
Keyword(s):  
Prescribed Fire ◽  
New South ◽  
Perennial Grass ◽  
Canopy Cover ◽  
Tree Cover ◽  
Woody Vegetation ◽  
Grass Cover ◽  
South Wales ◽  
Eastern Australia ◽  
The Relationship

The range of grass, shrub and tree levels present in the Louth region of western New South Wales was determined in an area where woody weeds are considered to be rampant, and the prospects for change by burning were evaluated. Relationships between the three vegetation elements in each of four major landforms were determined by regression and reduction in the canopy cover of woody vegetation after one or two fires were simulated. Basal cover of grass was negatively related to canopy cover of woody vegetation, except in the Sandplains and Dunefields landform. The relationship here was curvilinear with maximum grass cover occurring at 10% canopy cover of the woody vegetation. Pastoralism was considered to become less efficient when the canopy cover of woody vegetation exceeded 5%; 44% of sites measured were below this threshold. The remaining sites could be divided into two groups; one which would fall below the threshold if burnt with a prescribed fire (21%) and the other which required two fires or an equivalent second treatment to reduce the cover below the threshold (35%). The survey confirmed the perception of pastoralists, administrators and scientists that shrub cover is unacceptably high for pastoralism throughout much of the region. Additionally the perennial grass cover was very low and this would increase the instability of forage supply to pastoral herbivores. The high spatial variability in the composition of vegetation indicates that graziers need to identify and treat areas where return on investment in rehabilitation will be highest and most certain.

scholarly journals Metrics of Lidar-Derived 3D Vegetation Structure Reveal Contrasting Effects of Horizontal and Vertical Forest Heterogeneity on Bird Species Richness

2019 ◽  
Vol 11 (7) ◽  
pp. 743 ◽  
Author(s):  
Luis Carrasco ◽  
Xingli Giam ◽  
Monica Papeş ◽  
Kimberly Sheldon
Keyword(s):  
Species Richness ◽  
Bird Species ◽  
Structural Heterogeneity ◽  
Bird Species Richness ◽  
Vegetation Height ◽  
Vertical Heterogeneity ◽  
Animal Diversity ◽  
Bird Richness ◽  
Structural Metrics ◽  
Variance Explained

The structural heterogeneity of vegetation is a key factor for explaining animal diversity patterns at a local scale. Improvements in airborne light detection and ranging (lidar) technologies have enabled researchers to study forest 3D structure with increasing accuracy. Most structure–animal diversity work has focused on structural metrics derived from lidar returns from canopy and terrain features. Here, we built new lidar structural metrics based on the Leaf Area Density (LAD) at each vegetation height layer, and used these metrics to study how different aspects of forest structural heterogeneity explain variation in bird species richness. Our goals were to test: (1) whether LAD-based metrics better explained bird species richness compared to metrics based on the top of the canopy; and (2) if different aspects of structural heterogeneity had diverse effects on bird richness. We used discrete lidar data together with 61 breeding landbird points provided by the National Ecological Observatory Network at five forest sites of the eastern US. We used the lidar metrics as predictors of bird species richness and analyzed the shape of the response curves against each predictor. Metrics based on LAD measurements had better explanatory power (43% of variance explained) than those based on the variation of canopy heights (32% of variance explained). Dividing the forest plots into smaller grids allowed us to study the within-plot horizontal variation of the vertical heterogeneity, as well as to analyze how the vegetation density is horizontally distributed at each height layer. Bird species richness increased with horizontal heterogeneity, while vertical heterogeneity had negative effects, contrary to previous research. The increasing capabilities of lidar will allow researchers to characterize forest structure with higher detail. Our findings highlight the need for structure–animal diversity studies to incorporate metrics that are able to capture different aspects of forest 3D heterogeneity.

scholarly journals Listening to a changing landscape: Acoustic indices reflect bird species richness and plot-scale vegetation structure across different land-use types in north-eastern Madagascar

2021 ◽  
Vol 120 ◽  
pp. 106929 ◽  
Author(s):  
Saskia Dröge ◽  
Dominic Andreas Martin ◽  
Rouvah Andriafanomezantsoa ◽  
Zuzana Burivalova ◽  
Thio Rosin Fulgence ◽  
...  
Keyword(s):  
Land Use ◽  
Species Richness ◽  
Vegetation Structure ◽  
Bird Species ◽  
Bird Species Richness ◽  
Land Use Types ◽  
North Eastern

scholarly journals Acoustic indices applied to biodiversity monitoring in a Costa Rica dry tropical forest

2018 ◽  
Vol 2 (1) ◽  
pp. 1-1 ◽  
Author(s):  
Mónica I. Retamosa Izaguirre ◽  
Oscar Ramírez-Alán
Keyword(s):  
Tropical Forests ◽  
Diversity Index ◽  
Bird Species ◽  
Canopy Cover ◽  
Lower Percentage ◽  
Bird Diversity ◽  
Biodiversity Monitoring ◽  
Bird Abundance ◽  
Point Counts ◽  
Bird Richness

Standardized methods for biodiversity monitoring are needed to evaluate conservation efforts. Acoustic indices are used in biodiversity assessments, but need to be compared to traditional wildlife methods. This work was conducted in the Santa Rosa National Park between June and November, 2015. We installed recorders and conducted bird point counts in twelve sampling sites. We compared acoustic indices (Acoustic Evenness Index [AEI], Acoustic Diversity Index [ADI], Acoustic Complexity Index [ACI], Bioacoustic Index [BIO], Normalized Difference Soundscape Index [NDSI], Total Entropy [TE], Median Amplitude Envelope [MAE], Number of peaks [NP]) with indices from bird point counts (Bird Abundance, Bird Richness, Bird Diversity and Bird Evenness), and discuss the utility of acoustic indices as indicators for biodiversity monitoring in tropical forests. ADI, ACI, BIO and TE presented a similar temporal pattern peaking between 5 am and 6 am; and an additional peak at 5 pm, except for ACI. These patterns were consistent with the daily biological rhythms. AEI, ACI, BIO and Bird Abundance were related to characteristics of younger forests (lower percentage of canopy cover) but NP, ADI, TE, Bird Diversity and Bird Evenness were related to characteristics of older forests (higher percentage of canopy cover and a lower number of patches). ACI was positively correlated to Bird Abundance and NP was positively correlated to Bird Diversity. ACI reflects biological activity, but not necessarily a more diverse bird community in this study area. This might be an indication of a strong acoustic competition, or several highly dominant bird species in younger forests. Furthermore, acoustic communities in tropical forests commonly include insects (cicadas) and frogs, which might affect resulting acoustic indices. A variety of methods are probably needed to thoroughly assess biodiversity. However, a combination of indices such as ACI and NP might be considered to monitor trends in abundance and diversity of birds in dry forests.

scholarly journals Bird visits and resource use in Butia odorata (Arecaceae) palm groves in southern Brazil

2021 ◽  
Vol 111 ◽  
Author(s):  
Cyro Menezes da Glória ◽  
Alexandro Marques Tozetti
Keyword(s):  
Bird Species ◽  
Frugivorous Birds ◽  
Bird Species Richness ◽  
Palm Trees ◽  
Myiopsitta Monachus ◽  
Zonotrichia Capensis ◽  
Frequent Use ◽  
Bird Richness ◽  
Nesting Sites ◽  
Number Of Visits

ABSTRACT We evaluated avian use of a palm grove of Butia odorata (Barb. Rodr.) Noblick in the Brazilian Pampa. We recorded bird species richness, frequency of visits, and feeding behavior in palms trees with different flower and fruit availability. From January 2018 to February 2019, we observed 1,094 bird visits in 347 palm trees and identified 53 species. The most frequent visitors were Sicalis flaveola (Linnaeus, 1766), Myiopsitta monachus (Boddaert, 1783) and Zonotrichia capensis (Statius Muller, 1776). Perching was the most frequent use of palm trees by the birds (79%). Our hypothesis that an increase in the availability of flowers and fruits will be followed by a larger number of visits by insectivorous and frugivorous birds was not corroborated. In addition, there was a higher number of species visiting palm trees with no resources. The species composition and the number of guilds of visiting birds varied seasonally, but independently from resources availability. Bird richness, number of visits, and time length of visits did not vary between flowering/fruiting and resourceless palm trees. Based on this we argue that the main contribution of Butia odorata to the establishment of bird assemblages in palm groves is their role in offering perching, sheltering, and nesting sites.

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