Publications by authors named "Andrew J Abraham"

Previous studies have indicated that across birds and mammals, body mass is a comparatively poor predictor of the time digesta is retained in the digestive tract (mean retention time, MRT). Rather, MRT might be determined by gastrointestinal anatomy, which can differ considerably within and between trophic guilds. Here, we used two recent literature compilations on the intestine length and the MRT in birds (n = 33 species) and mammals (n = 149) and applied comparative statistical approaches to assess whether intestine length is more closely correlated with MRT than body mass.

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Megafauna (animals ≥45 kg) have probably shaped the Earth's terrestrial ecosystems for millions of years with pronounced impacts on biogeochemistry, vegetation, ecological communities and evolutionary processes. However, a quantitative global synthesis on the generality of megafauna effects on ecosystems is lacking. Here we conducted a meta-analysis of 297 studies and 5,990 individual observations across six continents to determine how wild herbivorous megafauna influence ecosystem structure, ecological processes and spatial heterogeneity, and whether these impacts depend on body size and environmental factors.

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Phosphorus (P) is essential for all life on Earth and sustains food production. Yet, the easily accessible deposits of phosphate-rich rock, which underpin the green revolution are becoming rarer. Here we propose a mechanism to help alleviate the problem of "peak phosphorus".

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The general observation that secondary consumers ingest highly digestible food and have simple short guts and small abdominal cavities intuitively results in the assumption that mammalian carnivores carry less digesta in their gut compared to herbivores. Due to logistic constraints, this assumption has not been tested quantitatively so far. In this contribution, we estimated the dry matter gut contents (DMC) for 25 species of the order Carnivora (including two strictly herbivorous ones, the giant and the red panda) using the physical 'Occupancy Principle', based on a literature data collection on dry matter intake (DMI), apparent dry matter digestibility (aD DM) and retention time (RT), and compared the results to an existing collection for herbivores.

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Article Synopsis
  • The extinction of big animals and plants is a major problem in our time, called the Anthropocene.
  • Big animals are at risk due to human activities like hunting, land use, and climate change, which affects how ecosystems work.
  • Losing these large creatures can seriously harm the environment, and we should focus on protecting them and large trees to help keep nature balanced and healthy.
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