Christine Pardo, undergrad member of the upwithclimate team, graduated today from Florida International University with her BSc in Biology! Way to go!
Upwithclimate teammember Brian Machovina has just pulled off a rare scientific trifecta: over the last month has published letters in PNAS, Science and Nature. All three letters address the need for reducing human consumption of meat in order to minimize habitat loss and anthropogenic impacts on biodiversity. The Science and PNAS letters were previously posted to upwithclimate here and here. I now post the new letter from Nature (a response to a previous comment article in Nature Eisler et al.). The Nature editors cruelly “butchered” the article to fit space constraints so I am posting the original, unedited (but still super short), version.
Livestock: Need for Global Limits
Brian Machovina & Kenneth J. Feeley
In “Agriculture: steps to sustainable livestock,” (see Eisler et al. Nature 507:32; 2014), the authors argue for improved breeding and cultivation of ruminants to provide better food sources. They mention a need to focus “on eating less, better quality meat,” and advocate for a diet containing only 300g of red meat (approximately the size of 3 decks of cards) per week. This is approximately 3.5-7% of a 2000 calorie-a-day diet depending on species and cut of meat. We strongly support the push to reduce consumption of ruminants, especially within a larger context of reducing overall meat consumption to a global average of 10% or less and with preferential use of meat sources with higher energy conversion efficiencies (i.e. chickens > pigs > ruminants). Globally, the average contribution of meat to the human diet is now approximately 30%. This varies greatly between countries, ranging from ~50% in the United States to ~5% for some developing countries. As such, reaching the proposed goal should ideally be achieved not only through an overall reduction in meat consumption, but also through a more equitable redistribution of consumption. A global maximum of 5% red meat in diets within a 10% maximum for all animal-based products would enable more people to be fed on less land (e.g., eliminating livestock and growing crops only for direct human consumption could feed an additional 4 billion people on extant agricultural lands1), thereby reducing or eliminating greenhouse gas emissions associated with conversion of natural habitats and biodiversity loss. The many other environmental impacts of agriculture related to use of water, fertilizer and fossil fuels, would also be reduced. Furthermore, a move towards more plant-based diets would result in many potential health benefits.2,3 Global meat consumption is increasing; this increase is not inevitable, nor is it beneficial to the planet or even human well-being.
1 Cassidy, E., West, P. C., Gerber, J. S. & Foley, J. A. Redefining agricultural yields: from tonnes to people nourished per hectare. Environmental Research Letters 8, 8 (2013).
2 Campbell, T. C. & Campbell, T. M. The China study: the most comprehensive study of nutrition ever conducted and the startling implications for diet, weight loss and long-term health. (Wakefield Press, 2007).
3 Levine, Morgan E. et al. Low Protein Intake Is Associated with a Major Reduction in IGF-1, Cancer, and Overall Mortality in the 65 and Younger but Not Older Population. Cell metabolism 19, 407-417 (2014).
A common concept in ecology is that predators have a strong influence on the behaviour of prey species. Anolis lizards have been used as a classic model system to investigate the effect of predator presence on the behavioural response of prey species. On small experimental islands in the Bahamas the manipulated introduction of curly-tailed lizards (Leiocephalus carinatus), a large terrestrial anole-predator, has resulted in brown anoles (Anolis sagrei) shifting higher up in the vegetation, presumably in an understandable effort to avoid being eaten (1, 2, 3). However, predator-prey interactions such as these which may shape community structure are often difficult to observe.
Here in Miami FL we have a rich and diverse, although largely non-native, lizard community. There are two species of “crown-giant” anoles, the Cuban knight anole (A. equestris) and the Jamaican giant anole (A. garmani), that could be potential predators of smaller anoles in the canopy of trees and upper half of tree trunks (although see Giery et al. 2013 for an empirical analysis that suggests this may not be the case). Additionally, there are several large, terrestrial lizards present which may be filling a similar role to curly-tails in the Bahamas.
Potential lizard predators in south Florida:
– *Red-headed agama (Agama agama)
– *Cuban knight anole (Anolis equestris)
– Jamaican giant anole (Anolis garmani)
– *Brown basilisk (Basiliscus vittatus)
– Spiny tailed iguana (Ctenosaura similis)
– Curly-tail lizard (Leiocephalus carinatus)
– Giant day gecko (Phelsuma grandis)
– Black and white tegu (Tupinambis merianae)
Earlier this afternoon, while taking a break from my office at Fairchild Tropical Botanical Gardens (a hot spot for any anologist visiting Miami; 1, 2, 3, 4) in a typical graduate student effort to put off work that I should be doing instead, fellow lab member Evan Rehm and I noticed some scuffling in a nearby bush. At around 2.5m, and admittedly on relatively precarious branches by this stage, sat an adult female African red-headed agama (A. agama) around 30cm from an adamantly motionless adult male Cuban brown anole (A. sagrei)! As we moved towards the bush the agama was quick to ungraciously thump itself to the floor, while the brown anole remained still. On closer inspection, it soon became apparent why both lizards were so high.
South Florida is a tough place to be an anole!
Adult male African red-headed agama (A. agama) at Fairchild Tropical Botanical Gardens, Miami FL. The population of agamas is localised to the botanical gardens; the source remains unclear but is likely an introduction from the pet trade – JStroud