Pre-Columbian soil fertilization and current management maintain food resource availability in old-growth Amazonian forests

Context Multiple scales of research are needed to understand the ecology and conservation requirements of species whose ecology is characterised by marked spatial and temporal dynamism. The flock bronzewing pigeon may provide a model for the conservation management of species with similar dispersive ecologies. Aims This study aimed to document the species composition and its variability in seeds consumed by flock bronzewing pigeons across a period of contrasting seasonal conditions, and to relate this diet to variation in food resource availability. Methods The diet of the flock bronzewing pigeon was described by analysis of the crop contents of samples collected over the period from June 2006 to September 2007 at one pastoral property on the Barkly Tablelands, Northern Territory. Variation in food resource availability was assessed using data from remote sensing, grassland community structure, and direct measurement of soil seed density. Multivariate statistical methods were used to test variation in plant community structure between years and among land units; generalised linear modelling was used to examine inter-annual variation in the abundance of key food plant species and seasonal variation in seed abundance. Key results Across the period of this study, the diet of flock bronzewing pigeons on the Barkly Tableland was largely restricted to seeds of a small number of plant species within Mitchell grasslands. Dietary patterns varied between years; evidence from remote sensing, grassland community structure, and seed density was consistent with these dietary patterns. Conclusions Flock bronzewing pigeons appear to be adapted to exploiting rare, episodic events, leading to high seed production by the ephemeral or annual component of perennial tussock grasslands. Key food plant species include the forbs Wedelia asperrima, Trichodesma zeylanicum and Phyllanthus lacerosus and the large-seeded annual grass Chionachne hubbardiana. These species may not be those that provide critical resources during unfavourable periods. Implications Conservation management of flock bronzewing pigeons will entail strategies to maintain key food species in grazed landscapes, and to ensure replenishment of seed reserves of annual and ephemeral plant species. Management practices to achieve these goals may include rotational wet season spelling of paddocks. More information is required on the focal areas for persistence within these black-soil grassland landscapes.

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The changing Amazon forest

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2007.0033 ◽

2008 ◽

Vol 363 (1498) ◽

pp. 1819-1827 ◽

Cited By ~ 142

Author(s):

Oliver L Phillips ◽

Simon L Lewis ◽

Timothy R Baker ◽

Kuo-Jung Chao ◽

Niro Higuchi

Keyword(s):

Twentieth Century ◽

Carbon Sink ◽

Global Climate ◽

Amazon Forest ◽

Old Growth ◽

Human Welfare ◽

Old Growth Forest ◽

Late Twentieth ◽

Amazonian Forests ◽

Late Twentieth Century

Long-term monitoring of distributed, multiple plots is the key to quantify macroecological patterns and changes. Here we examine the evidence for concerted changes in the structure, dynamics and composition of old-growth Amazonian forests in the late twentieth century. In the 1980s and 1990s, mature forests gained biomass and underwent accelerated growth and dynamics, all consistent with a widespread, long-acting stimulation of growth. Because growth on average exceeded mortality, intact Amazonian forests have been a carbon sink. In the late twentieth century, biomass of trees of more than 10 cm diameter increased by 0.62±0.23 t C ha −1 yr −1 averaged across the basin. This implies a carbon sink in Neotropical old-growth forest of at least 0.49±0.18 Pg C yr −1 . If other biomass and necromass components are also increased proportionally, then the old-growth forest sink here has been 0.79±0.29 Pg C yr −1 , even before allowing for any gains in soil carbon stocks. This is approximately equal to the carbon emissions to the atmosphere by Amazon deforestation. There is also evidence for recent changes in Amazon biodiversity. In the future, the growth response of remaining old-growth mature Amazon forests will saturate, and these ecosystems may switch from sink to source driven by higher respiration (temperature), higher mortality (as outputs equilibrate to the growth inputs and periodic drought) or compositional change (disturbances). Any switch from carbon sink to source would have profound implications for global climate, biodiversity and human welfare, while the documented acceleration of tree growth and mortality may already be affecting the interactions among millions of species.

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Daily variation of zooplankton abundance and evenness in the Rosana reservoir, Brazil: biotic and abiotic inferences

Iheringia Série Zoologia ◽

10.1590/1678-4766201410412131 ◽

2014 ◽

Vol 104 (1) ◽

pp. 21-31 ◽

Cited By ~ 1

Author(s):

Érica M. Takahashi ◽

Fábio A. Lansac-Tôha ◽

Juliana D. Dias ◽

Claudia C. Bonecker

Keyword(s):

Resource Availability ◽

Environmental Conditions ◽

Daily Variation ◽

Food Resource ◽

Zooplankton Community ◽

Abundant Species ◽

Zooplankton Abundance ◽

Temporal Fluctuation ◽

Abiotic Variables ◽

Temporal And Spatial

The zooplankton community presents stochastic temporal fluctuation and heterogeneous spatial variation determined by the relationships among the organisms and environmental conditions. We predicted that the temporal and spatial zooplankton distribution is heterogeneous and discrete, respectively, and that the daily variation of most abundant species is related to environmental conditions, specifically the availability of resources. Zooplankton samples were collected daily at three sampling stations in a lateral arm of the Rosana Reservoir (SP/PR). The zooplankton did not present significant differences in abundance and evenness among sampling stations, but the temporal variation of these attributes was significant. Abiotic variables and algal resource availability have significantly explained the daily variation of the most abundant species (p<0.001), however, the species distribution makes inferences on biotic relationships between them. Thus, not only the food resource availability is influential on the abundance of principal zooplankton species, but rather a set of factors (abiotic variables and biotic relationships).

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Seasonal oestrous cycle activity of captive female koalas in south-east Queensland

Australian Mammalogy ◽

10.1071/am14018 ◽

2015 ◽

Vol 37 (2) ◽

pp. 245 ◽

Cited By ~ 2

Author(s):

K. Ballantyne ◽

A. Lisle ◽

A. Mucci ◽

S. D. Johnston

Keyword(s):

Resource Availability ◽

Food Resource ◽

Reproductive Function ◽

Genetic Management ◽

Confounding Effect ◽

Influence Of Temperature ◽

Reproductive Management ◽

Captive Populations ◽

Autumn And Winter ◽

Sexually Mature

This study investigated the seasonality of behavioural oestrus in a captive koala population in south-east Queensland. A total of 33 sexually mature koalas were examined over a 4-year period (2009–12) to determine the possible influence of temperature, photoperiod and rainfall on the incidence of expression of behavioural oestrus without the confounding effect of lactation or limiting food resource availability. Although signs of behavioural oestrus were detected throughout the year, an obvious seasonality was apparent, with significantly fewer females displaying behavioural oestrus in late autumn and winter (May–August) than September to April (P < 0.0001). While average monthly photoperiod (P < 0.0001) and average monthly temperature (P < 0.0001) were significantly related to oestrous behaviour, rainfall was not (P > 0.05). A better understanding of the seasonality of reproductive function in the female koala will facilitate the use of reproductive management-assisted breeding technology to enable improved genetic management in captive populations.

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Resource-driven encounters among consumers and implications for the spread of infectious disease

Journal of The Royal Society Interface ◽

10.1098/rsif.2017.0555 ◽

2017 ◽

Vol 14 (135) ◽

pp. 20170555 ◽

Cited By ~ 7

Author(s):

Rebecca K. Borchering ◽

Steve E. Bellan ◽

Jason M. Flynn ◽

Juliet R. C. Pulliam ◽

Scott A. McKinley

Keyword(s):

Resource Availability ◽

Food Resource ◽

Maximum Distance ◽

Spatially Explicit ◽

Encounter Rate ◽

Supplemental Food ◽

Resource Density ◽

Critical Resource ◽

The Relationship ◽

Theoretical Results

Animals share a variety of common resources, which can be a major driver of conspecific encounter rates. In this work, we implement a spatially explicit mathematical model for resource visitation behaviour in order to examine how changes in resource availability can influence the rate of encounters among consumers. Using simulations and asymptotic analysis, we demonstrate that, under a reasonable set of assumptions, the relationship between resource availability and consumer conspecific encounters is not monotonic. We characterize how the maximum encounter rate and associated critical resource density depend on system parameters like consumer density and the maximum distance from which consumers can detect and respond to resources. The assumptions underlying our theoretical model and analysis are motivated by observations of large aggregations of black-backed jackals at carcasses generated by seasonal outbreaks of anthrax among herbivores in Etosha National Park, Namibia. As non-obligate scavengers, black-backed jackals use carcasses as a supplemental food resource when they are available. While jackals do not appear to acquire disease from ingesting anthrax carcasses, changes in their movement patterns in response to changes in carcass abundance do alter jackals' conspecific encounter rate in ways that may affect the transmission dynamics of other diseases, such as rabies. Our theoretical results provide a method to quantify and analyse the hypothesis that the outbreak of a fatal disease among herbivores can potentially facilitate outbreaks of an entirely different disease among jackals. By analysing carcass visitation data, we find support for our model's prediction that the number of conspecific encounters at resource sites decreases with additional increases in resource availability. Whether or not this site-dependent effect translates to an overall decrease in encounters depends, unexpectedly, on the relationship between the maximum distance of detection and the resource density.

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