Variation in bird assemblages and their invertebrate prey in eucalypt formations across a rainfall gradient in south-west Australia

2017 ◽  
Vol 23 (4) ◽  
pp. 372
Author(s):  
Jonathan D. Majer ◽  
Harry F. Recher ◽  
Christopher Norwood ◽  
Brian E. Heterick

Our previous work has shown how invertebrate food resources influence usage of tree species by birds. Using data from Western Australian forests and woodlands, we extend the findings to indicate how the avifauna is influenced by these resources at the landscape level. The northern dry sclerophyll forest of south-west Australia comprises jarrah (Eucalyptus marginata) to the west, with an abrupt replacement by wandoo (E. wandoo) plus powderbark wandoo (E. accedens) woodland to the east; codominant marri (Corymbia calophylla) trees occur throughout. Knockdown samples have previously indicated that the canopy invertebrate fauna is richer and more abundant in wandoo woodland than in jarrah/marri forest. To provide an indication of their general abundance and diversity in these formations, invertebrates using the trunks of the ubiquitous marri were measured along a transect from jarrah/marri forest to wandoo woodland. Mirroring the canopy, the trunk fauna had high species turnover over short distances. As with the canopy fauna, invertebrate diversity and abundance was higher on marri situated in the wandoo zone than in the jarrah/marri areas, indicating a generally larger invertebrate fauna in the drier regions of the transect. Abundance and diversity of birds, many of which are wholly or partly insectivorous, were measured at the same sites. Birds were more abundant and there were more species in areas with the wandoo species than in those dominated by jarrah/marri. Assemblage composition also differed in the two forest types. It is evident that changes in bird abundance, richness, and assemblage composition are likely determined on a landscape scale by the type, abundance, and diversity of food resources available to them. These patterns of change within forest invertebrate faunas and their primary vertebrate predators need to be considered when making decisions on conserving or managing forest communities in Australia.

The Condor ◽  
2021 ◽  
Author(s):  
Kyle D Kittelberger ◽  
Montague H C Neate-Clegg ◽  
Evan R Buechley ◽  
Çağan Hakkı Şekercioğlu

Abstract Tropical mountains are global hotspots for birdlife. However, there is a dearth of baseline avifaunal data along elevational gradients, particularly in Africa, limiting our ability to observe and assess changes over time in tropical montane avian communities. In this study, we undertook a multi-year assessment of understory birds along a 1,750 m elevational gradient (1,430–3,186 m) in an Afrotropical moist evergreen montane forest within Ethiopia’s Bale Mountains. Analyzing 6 years of systematic bird-banding data from 5 sites, we describe the patterns of species richness, abundance, community composition, and demographic rates over space and time. We found bimodal patterns in observed and estimated species richness across the elevational gradient (peaking at 1,430 and 2,388 m), although no sites reached asymptotic species richness throughout the study. Species turnover was high across the gradient, though forested sites at mid-elevations resembled each other in species composition. We found significant variation across sites in bird abundance in some of the dietary and habitat guilds. However, we did not find any significant trends in species richness or guild abundances over time. For the majority of analyzed species, capture rates did not change over time and there were no changes in species’ mean elevations. Population growth rates, recruitment rates, and apparent survival rates averaged 1.02, 0.52, and 0.51 respectively, and there were no elevational patterns in demographic rates. This study establishes a multi-year baseline for Afrotropical birds along an elevational gradient in an under-studied international biodiversity hotspot. These data will be critical in assessing the long-term responses of tropical montane birdlife to climate change and habitat degradation.


2020 ◽  
Author(s):  
Geoff Williams

The Invertebrate World of Australia’s Subtropical Rainforests is a comprehensive review of Australia’s Gondwanan rainforest invertebrate fauna, covering its taxonomy, distribution, biogeography, fossil history, plant community and insect–plant relationships. This is the first work to document the invertebrate diversity of this biologically important region, as well as explain the uniqueness and importance of the organisms. This book examines invertebrates within the context of the plant world that they are dependent on and offers an understanding of Australia’s outstanding (but still largely unknown) subtropical rainforests. All major, and many minor, invertebrate taxa are described and the book includes a section of colour photos of distinctive species. There is also a strong emphasis on plant and habitat associations and fragmentation impacts, as well as a focus on the regionally inclusive Gondwana Rainforests (Central Eastern Rainforest Reserves of Australia) World Heritage Area. The Invertebrate World of Australia’s Subtropical Rainforests will be of value to professional biologists and ecologists, as well as amateur entomologists and naturalists in Australia and abroad.


2004 ◽  
Vol 52 (4) ◽  
pp. 435 ◽  
Author(s):  
B. L. Shearer ◽  
C. E. Crane ◽  
A. Cochrane

This study compares, for the first time, variation in estimates of susceptibility of native flora to Phytophthora cinnamomi Rands among four databases and proposes an estimate of the proportion of the flora of the South-West Botanical Province of Western Australia that is susceptible to the pathogen. Estimates of the susceptibility of south-western native flora to P. cinnamomi infection were obtained from databases for Banksia woodland of the Swan Coastal Plain, jarrah (Eucalyptus marginata Donn. ex Smith) forest, the Stirling Range National Park and Rare and Threatened Flora of Western Australia. For the woodland, forest and national park databases, hosts were naturally infected in uncontrolled diverse natural environments. In contrast, threatened flora were artificially inoculated in a shadehouse environment. Considerable variation occurred within taxonomic units, making occurrence within family and genus poor predictors of species susceptibility. Identification of intra-specific resistance suggests that P. cinnamomi could be having a strong selection pressure on some threatened flora at infested sites and the populations could shift to more resistant types. Similar estimates of the proportion of species susceptible to P. cinnamomi among the databases from the wide range of environments suggests that a realistic estimate of species susceptibility to P. cinnamomi infection in the south-western region has been obtained. The mean of 40% susceptible and 14% highly susceptible equates to 2284 and 800 species of the 5710 described plant species in the South-West Botanical Province susceptible and highly susceptible to P. cinnamomi, respectively. Such estimates are important for determining the cost of disease to conservation values and for prioritising disease importance and research priorities. P. cinnamomi in south-western Australia is an unparalleled example of an introduced pathogen with a wide host range causing immense irreversible damage to unique, diverse but mainly susceptible plant communities.


1998 ◽  
Vol 8 (3) ◽  
pp. 297-308 ◽  
Author(s):  
Lorena Calvo ◽  
John Blake

SummaryMany studies have examined differences in bird communities between shade and sun coffee plantations but less is known about how different management practices within shade coffee plantations affect bird populations. This study compares diversity and abundance of resident and migrant birds in two shade coffee plantations located in Palajunoj, Quetzaltenango, Guatemala, that differ in their farming practices (e.g. pruning schedules and fertilizer regimes) and, consequently, in vegetation structure. One plantation represents a traditional, polyculture shade system whereas the second represents a more modernized, monoculture shade system. Both plantations supported many resident and migrant birds. Bird abundance and diversity were significantly greater during both wet and dry seasons on the traditional farm, due largely to the vegetation structure resulting from the different management practices. All plantations typically classified as ‘shade coffee’ are not equivalent, much of their conservation value coming from the more diverse and structurally complex traditional polycultures rather than from the newer, monocultural systems. Coffee production techniques that affect the structural and floristic diversity of the vegetation (e.g. pruning, application of chemicals) have important consequences for birds.


2017 ◽  
Vol 159 ◽  
pp. 48-61 ◽  
Author(s):  
Mélanie J. Banville ◽  
Heather L. Bateman ◽  
Stevan R. Earl ◽  
Paige S. Warren

2015 ◽  
Vol 21 (2) ◽  
pp. 133
Author(s):  
K. R. Whitford ◽  
D. Wiseman ◽  
W. L. McCaw ◽  
F. J. Bradshaw

Johnstone et al. (2013) (Pacific Conservation Biology 19, 122–141) make a substantial contribution to the knowledge of the forest red-tailed black cockatoo (Calyptorhynchus banksii naso) (FRTBC), presenting data on nest hollows and nest tree attributes. They discuss the threats to the current and future breeding hollows and conclude that ‘we are facing a major crisis in southern forests’. Although there are sound reasons for concern over the conservation of cockatoo species, the imminence of a crisis is not established by the data presented. We provide spatial and management context and present data relevant to discussion of threats to FRTBC hollows in south-west Western Australia. The primary strategy for providing habitat across the publicly owned forests is reservation, which formally excludes timber harvesting from more than 50% (1.3 million ha) of the forest, informally protects a further 11%, and protects habitat trees within harvested areas. Timber harvesting in these forests generally involves partial cutting, which retains trees of a wide range of size and age classes. A realistic minimum age for trees bearing hollows used by FRTBC in the jarrah (Eucalyptus marginata) forest is ~120–150 years (trees diameters of 50–60 cm), well below the 209 years highlighted by Johnstone et al. (2013). Most nest hollows occur in intermediate-sized trees. Clustering of FRTBC nest trees was not demonstrated in their data but is worthy of further investigation. Improved estimates of nest tree availability and loss would provide perspective on the threats to FRTBC, as would knowledge of population size and age structure of the FRTBC. The protection of known nest trees and control of feral competitors, where possible, would benefit FRTBC.


Author(s):  
M. Paula Raffo ◽  
M. Cecilia Eyras ◽  
Oscar O. Iribarne

Biological invasions can alter the biodiversity of native communities generating an ecological impact that in many cases is irreversible. In 2001, Undaria pinnatifida invaded Macrocystis pyrifera kelp in Cracker Bay (42°56′S, 64°27′W; Northern Patagonia, Argentina). The possible impact of that invasion was evaluated in March 2004 with a study of population and morphological parameters of both kelp species and their associated holdfast biodiversity. Three nearby areas of spatial distribution of the kelps were differentiated, one dominated by M. pyrifera (M), an intermediate area characterized by M. pyrifera and U. pinnatifida (M+U), and another dominated by U. pinnatifida (U). In each area, sporophytes in nine quadrats of 1 m2 were collected. The density and biomass m−2, the height of the sporophytes and the size of the holdfast of  M. pyrifera did not diminish in the presence of  U. pinnatifida. The richness, abundance and diversity of the flora associated with the holdfast of both kelps were similar, whereas these parameters were higher in the case of the fauna associated to M. pyrifera than U. pinnatifida Results obtained in this work suggest that, at this invasion stage, there is no evidence of interspecific competition. Nevertheless, since density and diversity of the fauna associated with the holdfast is different, we expect community changes if the U. pinnatifida invasion continues to expand.


2020 ◽  
Author(s):  
Elizabeth A. Bergey ◽  
Benjamin E. Whipkey

AbstractResidential yards constitute a substantive biodiverse greenspace within urban areas. This biodiversity results from a combination of native and non-native species and can contribute to biotic homogenization. Geographical climatic patterns affect the distribution of native species and may differently affect non-native species. In this study, we examined biodiversity and biotic homogenization patterns of yard-dwelling land snails across 12 towns in Oklahoma and Kansas (USA). The 3 × 4 array of towns incorporated a N-S winter temperature gradient (mean low January temperature range = −8.4 to 0.1 °C) and an E-W annual rainfall gradient (annual rainfall range = 113.8 to 61.3 cm/yr). Ten yards per town were surveyed. We hypothesized that mild winter temperatures and greater annual rainfall would be associated with greater snail abundance and richness, and that the presence of non-native species would contribute to biotic homogenization. Non-native snails were present and often abundant in all towns. Snail communities varied with both rainfall and cold temperature. Contrary to our prediction, snail abundance was inversely related to annual rainfall – likely because drier conditions resulted in greater yard watering that both augmented rainfall and maintained moist conditions. Sørensen similarity between towns for the entire land snail community and for only non-native species both showed distance-decay patterns, with snail composition becoming less similar with increasing distance - patterns resulting from species turnover. The biotic homogenization index also showed a distance-decay pattern, such that closer towns were more likely to have biotic homogenization whereas more distant towns tended to have biotic differentiation. These results support the concept that biotic homogenization is more likely regionally and that climatic changes over distance result in species turnover and can reduce spatially broad biotic homogenization.


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