The University of Southampton

Tag: Agriculture

Will Intensifying Agriculture Save Us, or Starve Us?

Posted on by Deanna Fox

The surge in human population in recent years is predicted to reach an unprecedented 9.1 billion people by 2050 – a 14% increase of our current population (McKee et al., 2004). This epidemic of population growth means we are faced with the daunting challenge of attaining sustainable increase in crop production to meet the increasing food demands.

Anthropogenic disturbance in natural landscapes is one of the largest contributors to biodiversity loss. Here is the aftermath of land clearance for palm oil plantations, Borneo. Photo credit: Rhett A. Butler (2012). Available at: https://news.mongabay.com/2012/09/agriculture-causes-80-of-tropical-deforestation/
Anthropogenic disturbance in natural landscapes is one of the largest contributors to biodiversity loss. Here is the aftermath of land clearance for palm oil plantations, Borneo (Butler, 2012).

Global agricultural intensification has increased our food production to meet this demand through conversion of natural to simplified agricultural landscapes and escalating the application of agrochemicals such as pesticides and fertilisers (Matson et al., 1997). This simplification is a major cause of the accelerating loss of biodiversity, which affects ecological processes such as nutrient recycling, carbon storage and pollination (Flynn et al., 2009).

A biotic communities’ functional traits (i.e. characteristics) influences ecosystem functioning through mediating changes in biotic processes, such as predation and competition (Wood et al., 2015). For example, where there are collectively few traits in a community, circumstances of “niche overlap” are common, meaning ability to utilise a broad range of resources within a community decreases, whilst competition for a narrow selection resources increases (Flynn et al., 2009).

Figure 1: Theoretical total functional traits in natural, low-intensity agriculture, intensive agriculture, and managed through polyculture settings4.
Figure 1: Theoretical total functional traits in natural, low-intensity agriculture, intensive agriculture, and managed through polyculture settings (Wood et al., 2015).

Intensive agriculture may degrade (A) the number of functional traits in a given area (functional trait space). However, theoretically implementing adequate management strategies promoting multi-species crops (polycultures) may aid limited recovery of total functional traits (B), recovery to the levels of natural counterparts (C), or even exceed this (D) by endorsing evolution of new species with novel traits (figure 1).

Biodiversity loss through agricultural intensification has been reported for birds, insects, plants and mammals, along with functional trait diversity (Flynn et al., 2009).

 

 

 

“Between 1970 and 1990, 86% of farmland bird species had reduced ranges and 83% had declined in abundance [in Europe]” (Benton et al., 2003)

 

The resulting loss of functional traits (including foraging strategies and diet) has significant implications for the removal of insects from farmland, whereby insect subtraction is reduced. The disruptive effects this has on pest communities increases the risk of outbreaks, which not only influences community structures, but hinders crop productivity (Wood et al., 2015).

Application of pesticides to a monoculture crop in an attempt to control pest population. Photo credit Unknown. Available at: http://sitn.hms.harvard.edu/flash/2015/gmos-and-pesticides/
Application of pesticides to a monoculture crop in an attempt to control pest population (Hsaio, 2015)

Shifts toward monoculture (single-species) crops, and reduced predation, facilitates the spread of pests, increasing the risk of epidemics. Pesticides are commonly used as a control measure, although are often toxic to many species.  DDT, commonly used through the mid-20th century, accumulates in increasingly high concentrations up food chains between predators. This concentration may increase thousand-fold or more, of the content in the original source. This caused the endangerment of many predatory birds such as the peregrine falcon and kestrel through thinning their egg shells thus increasing infant mortality. Loss of top predators disrupts regulation of species populations further down the chain, unbalancing the community (Peakall, 1970).

Biodiversity loss is having severe adverse impacts on the health of our biotic communities, and therefore ecosystems. While agriculture cannot be halted all together, we could improve crop strength through diversity through implementing adequate management strategies to promote biodiversity, and use this to control pest outbreaks in an ecologically sensitive manner.

 

References

Benton, T. G., Vickery, J. A. and Wilson, J. D. (2003) ‘Farmland biodiversity: Is habitat heterogeneity the key?’, Trends in Ecology and Evolution, 18(4), pp. 182–188. doi: 10.1016/S0169-5347(03)00011-9.

Butler, R. A. (2012) Agriculture causes 80% of tropical deforestation, Mongabay. Available at: https://news.mongabay.com/2012/09/agriculture-causes-80-of-tropical-deforestation/ (Accessed: 21 March 2017).

Flynn, D. F. B., Gogol-Prokurat, M., Nogeire, T., Molinari, N., Richers, B. T., Lin, B. B., Simpson, N., Mayfield, M. M. and DeClerck, F. (2009) ‘Loss of functional diversity under land use intensification across multiple taxa’, Ecology Letters, 12(1), pp. 22–33. doi: 10.1111/j.1461-0248.2008.01255.x.

Hsaio, J. (2015) GMOs and Pesticides: Helpful or Harmful?, Harvard University: The Graduate School of Arts and Sciences. Available at: http://sitn.hms.harvard.edu/flash/2015/gmos-and-pesticides/ (Accessed: 20 March 2017).

Matson, P. A., Parton, W. J., Power, A. G. and Swift, M. J. (1997) ‘Agricultural Intensification and Ecosystem Properties.’, Science, 277(5325), pp. 504–509. doi: 10.1126/science.277.5325.504.

McKee, J. K., Sciulli, P. W., Fooce, C. D. and Waite, T. A. (2004) ‘Forecasting global biodiversity threats associated with human population growth’, Biological Conservation, 115(1), pp. 161–164. doi: 10.1016/S0006-3207(03)00099-5.

Peakall, D. B. (1970) ‘Pesticides and the reproduction of birds.’, Scientific American, 222, pp. 72–78. Available at: http://sitn.hms.harvard.edu/flash/2015/gmos-and-pesticides/.

Wood, S. A., Karp, D. S., DeClerck, F., Kremen, C., Naeem, S. and Palm, C. A. (2015) ‘Functional traits in agriculture: Agrobiodiversity and ecosystem services’, Trends in Ecology and Evolution. Elsevier Ltd, 30(9), pp. 531–539. doi: 10.1016/j.tree.2015.06.013.

 

[492 words]



Nasty Neonicotinoids: The cause of declines in Birds, Bees and Butterflies

Posted on by Imogen Ryan

 

As agriculture has intensified over the last century we have seen falling food prices and bigger fruit and veg, but what is the cost to our wildlife?

The increase in size of modern arable fields provides a veritable feast for many pests, destroying large areas of crop and literally eating into farmer’s profits. This has led to a rise in the use of pesticides to control these pests. However, not all the animals that are negatively affected by pesticides are harmful to crops, in fact some are beneficial.

Neonicotinoids

In the 1990’s a group of insecticides called neonicotinoids were developed which could be added to seeds before planting rather than externally sprayed onto the plants. The plant incorporates the chemical into all its tissues, giving insect pests a fatal dose upon taking a bite (Gilburn, 2015). This is good news for those beneficial animals that don’t munch their way through the crop right?

Wrong! The chemical gets into every part of the plant including the pollen and nectar (Blacquire et al 2012) which bees and butterflies feed on while pollinating plants. Farmland birds also often eat the seeds before they sprout. These animals don’t even have to be in the field to be affected as the majority of the chemical is not taken up by the plant and is leached into the soil water (Hallman et al 2014) and transported to wildflower field margins and neighbouring land.

What are the effects? 

Butterflies

The populations of widespread butterflies on monitored UK farmland sites have declined by 58% between 2000 and 2009 (Brereton et al 2011). This is negatively correlated with the increase in the use of neonicotinoids (Gilburn, 2015). Although it has not been proved to be a cause and effect relationship, the sudden decline in butterflies has not been seen in Scotland (Brereton et al 2011) where less neonicotinoids are used (Defra, 2014).

Painted Lady Butterfly -Alamy

Bees

Neonicotinoids are also threatening bees, impairing their homing ability and learning as well as their immunity to viruses. The chemical also reduces the growth of the colony and the production of queens (Cresswell, 2011). A recent field study by Rundolf et al (2015) has shown that the density of wild bees, nesting of solitary bees and growth of bumblebee colonies have all been reduced by neonicotinoid treated rape seeds.

neonicotinoid-pesticides-their-effect-on-bee-colonies-the-facts

Out for the count. Julia Garvin

 

Birds

A decline in insectivorous farmland birds, correlated with neonicotinoid use, has also been seen in the Netherlands (Hallman et al 2014). This is thought to be due to directly consuming the poisonous seeds (Goulson, 2013) or through the reduction in their insect food source.

Grey Partridge-Cambridge Bird Club

 

Do we need neonicotinoids anyway?

The use of neonicotinoids also appears to have no benefits to agricultural yields of soybean (Myers, 2014), Sunflower and Maize crops (Susuki, 2014). Methods like Integrated Pest Management can reduce the number of pests without the powerful chemicals so isn’t it time we put nature before ease?

More information on the effect on bees

References  painted-lady 

Blacquiere T, Smagghe G, Van Gestel CAM, Mommaerts V. 2012. ` Neonicotinoids in bees: a review on concentrations, side-effects and risk assessment. Ecotoxicology 21:973–992

Brereton TM, Roy DB, Middlebrook I, Botham M, Warren M. 2011. The development of butterfly indicators in the United Kingdom and assessments in 2010. Journal of Insect Conservation 15:139–151

Cresswell JE. 2011. A meta-analysis of experiments testing the effects of a neonicotinoid insecticide (imidacloprid) on honey bees. Ecotoxicology 20:149–157

Defra. 2014. Pesticide usage statistics. Available at https://secure.fera.defra.gov.uk/pusstats/ (accessed March 2017).

Gilburn, A.S., Bunnefeld, N., Wilson, J.M., Botham, M.S., Brereton, T.M., Fox, R., and Goulson, D. (2015). Are neonicotinoid insecticides driving declines of widespread butterflies? PeerJ:e1402

Goulson, D. (2013). An overview of the environmental risk posed by neonicotinoid insecticides. J. Appl. Ecol. 50, 977-987

Hallmann CA, Foppen RPB, Van Turnhout CAM, De Kroon H, Jongejans E. 2014. Declines in insectivorous birds are associated with high neonicotinoid concentrations. Nature 511:341–343

Myers, C., Hill, E. (2014). Benefits of Neonicotinoid Seed Treatments to Soybean Production. US Environmental protection agency

Rundlof M, Andersson GKS, Bommarco R, Fries I, Hederstrom V, Jonsson O, Klatt BK, ¨ Pedersen TR, Yourstone J, Smith HG. 2015. Seed coating with a neonicotinoid insecticide negatively affects wild bees. Nature 521:77–80

Susuki, D. (2014). More Bad News for Bees. Available at http://www.ecology.com/2014/10/31/the-new-word-for-bees/ (accessed March 2017)

Word Count [487]

 



Crops and Climate Change: the good, the bad and the ugly truth

Posted on by Anonymous

New Year, New Hope? But 2017 began with Britain being hit with a vegetable shortage!

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(Independent, 2017)                                                    (The Guardian, 2017)

But apart from halting our “clean eating” resolutions…..

Is a courgette shortage really the end of the world?

Well, probably not! But globally, food security is no laughing matter.

 And what is the cause you may ask? Climate change, of course!

The evidence for climate change is overwhelming.

The Earth’s average temperature has increased by 0.85°C between 1980-2012 (IPCC, 2014). This may seem insignificant, yet, it has severe consequences, such as the ice caps melting, sea levels rising and increased occurrence of extreme weather events (Overpeck and Cole, 2006).

3

Globally averaged combined land and ocean surface temperature (IPCC, 2014)

Humans are to blame.

Since the industrial revolution, burning of fossil fuels has increased emissions of carbon dioxide (CO2) and other greenhouse gases (GHGs) These GHGs act as a blanket, trapping energy in the atmosphere, causing Earth’s temperature to rise (IPCC, 2014).

4

Global Human CO2 Emissions, IPCC, 2014

The good?

Higher CO2 levels increase plant photosynthesis (Pospisilova and Catsky, 1999). Photosynthesis depends on an enzyme called Rubisco, which evolved at higher prehistoric CO2 levels, therefore has higher activity when CO2 increases (Bowes, 1996). This increases plant growth, thereby increasing crop yield, in a phenomenon termed “CO2-fertlisation” (Allen, 1990).

This is particularly pronounced plants categorised at C3 , which includes major crops such as rice, wheat and soybean. Increasing CO2 to 550pm causes 10-20% increase in C3 crop yield, but only 0-10% increase plants categorised as C4, which includes the crops maize and sorghum (Schmidhuber and Tubiello, 2007).

CO2 enters plants through stomata (plant pores), therefore, at higher CO2 levels the stomata need not open as often, termed reduced stomatal conductance. This decreases the amount of water lost through the pores in the process of transpiration, thereby increasing the water efficiency of the plants (Drake et al., 2007).

The bad?

So, is climate change good for plants if it causes increased growth and higher water efficiency? Well no, it was never going to be that simple…

Extreme weather events negatively impact food security, both directly by reduced yields from damaged crops but also indirectly by increasing the chance of landslides and soil erosion, thereby reducing the land available for agriculture (Cerri et al., 2007).

This issue is becoming more urgent as global population increases at an unprecedented rate, increasing the demand for food (MA, 2005).

Food security issues are not only concerned with the quantity of food but also the quality, as globally many people suffer from malnutrition (MA, 2005). Elevated CO2 decreases the zinc, iron, and protein content in wheat, barley, and rice (Myers et al., 2014).

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The two-fold effect of increased CO2 form increased carbon emissions; most likely the negative effect will outweigh the positive effect. 

The ugly truth

Unfortunately, it is predicted the losses will outweigh any gains from CO2 fertilisation.

Ultimately, lack of food could see increased prices for consumers in the developed world whilst the developing world will suffer with food shortage and malnutrition.

Lack of courgettes may seem a trivial matter but is it just one more sign that we getting closer to the tipping point of our planet’s ability to cope with climate change.

Word count: 499

References

Allen, L.H. Jr. (1990). Plant responses to rising carbon dioxide and potential interactions with air pollutants. J. Environ. Qual, 19: 15-34.

Bowes G. (1996) Photosynthetic responses to changing atmospheric carbon dioxide. pp. 387-407. In: N.R. Baker (ed.). Photosynthesis and the Environment. Advances in Photosynthesis, Vol. 5, Kluwer, Dordrecht

Cerri, C. E.P., Sparovek, G., Bernoux, M., Easterling, W.E., Melillo, J. M., and Cerri C. C. (2007). Tropical Agriculture and Global Warming: Impacts and Mitigation Options. Sci. Agric., 64(1): 83-89.

Drake, B.G., Gonzàlez-Meler, M.A. and Long, S.P., 1997. More efficient plants: a consequence of rising atmospheric CO2? Annual review of plant biology, 48(1): 609-639.

IPCC. (2014) Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. R.K. Pachauri and L.A. Meyer (eds.). IPCC, Geneva, Switzerland, pp. 151.

Millennium Ecosystem Assessment (2005). Ecosystems and Human Well-being: Synthesis. Island Press, Washington, DC.

Myers SS, Zanobetti A, Kloog I, et al. (2014). Rising CO2 threatens human nutrition. Nature. 510(7503): 139-142.

Overpeck, J.T. and Cole, J.E. (2006). Abrupt change in Earth’s climate system. Annual Review of Environment and Resources, 31: 1-31.

Pospisilova, J. and Catsky, J. (1999). Development of water stress under increased atmospheric CO2 concentration. Biologia Plantarum, 42: 1-24.

Schmidhuber, J. and Tubiello, F.N. (2007). Global food security under climate change. Proc. Natl. Acad. Sci. USA, 104(50): 19703-8.



How do you like your toast in the morning? Without the worry of food security?

Posted on by Imogen Vieten

80% of human calorie intake comes from 6 major crops including – maize, wheat and rice1. For all people, at all times to have physical and economic access to sufficient food needed for a balanced diet2–food security, the production and distribution of these crops is vital.

Present day representation of global vulnerability to food insecurity8. Explore scenarios of Greenhouse gas emissions and adaptation to climate change impacts on food security by clicking on the link: http://www.metoffice.gov.uk/food-insecurity-index/ Present day representation of global vulnerability to food insecurity3. Explore scenarios of Greenhouse gas emissions and adaptation to climate change impacts on food security by clicking on the image.

A growing human population increases pressure to enhance crop production. 1 billion ha of land will be converted by 2050 for agriculture, reducing absorption of atmospheric carbon dioxide by plants2 and restoration of gaseous balance in the atmosphere, with fewer plants to act as a CO2 ‘sink’.

Human induced climate change is negatively affecting ecosystems, crop yield and production. Since the industrial revolution greenhouse gas emissions have risen, with atmospheric CO2 levels currently at 406.42ppm4, meaning plants are growing in conditions not experienced for 26 million years5.

Impacts of future climate change are predicted to be severe, varying between regions, through changes in temperature, precipitation and increases in extreme weather events. Methods of crop production such as sustainable intensification are needed to increase yields and overcome threats to livelihoods and food security2.

Will increased CO2 result in higher crop yields?

During photosynthesis plants use CO2, water and light to produce oxygen and carbohydrates for growth. Efficiency of this depends on the enzyme Rubisco, which functions better in high CO2, shown experimentally to increase photosynthesis by 58%5. There is evidence that the number and size of individual cells increase in elevated CO26, showing species specific adaptive ability7,  indicating potential to increase crop yield. However other climatic stresses will have negative effects.

The temperature dependant action of Rubisco may become less efficient with rising global temperatures. Furthermore in the long term, plants can acclimatise as additional carbohydrates produced from photosynthesis cannot be used5.

During extended periods of high CO2 exposure the number of stomata- pores used in gaseous exchange in leaves, may decrease indicating that photosynthetic rate will too7.

How will crop production be affected?

For sustainable intensification sufficient water and nutrients8 are required, which will be threatened by increased extreme weather events- from drought affecting water supply to storms where heavy downpours can wash away top soil, reducing land fertility.

Threats to global productivity and changes in yield could have impacts worldwide8. If production decreases, prices of grain products and meat reliant on grain as a feedstock will increase8. Furthermore lower agricultural output, especially in the developing world, leads to lower incomes, with the poorest suffering the most.

High CO2 can decrease food quality with a decline in protein, nitrogen, zinc and iron concentrations in crops9, potentially causing adverse health effects, and necessitating consumption of greater quantities.

Securing the future

FACE (Free-air concentration enrichment) experiments expose crops to elevated CO2 to examine responses and adaptions of ecosystems. Research to develop climate resilient crop varieties to better cope with heat, drought and salinity is also being conducted.

By adapting farming mechanisms and increasing yield and tolerance of essential crop species to environmental extremes, can we ensure food security? Yes, the time to act is now!

 

Discover more about how farmers may adapt their practices to a changing climate in the video ‘Feeding Nine Billion’10

 

[499 Words]

References

  1. Campell, N,A., Reece, J, B., Urry, L,A., Cain, M,L., Wasserman, S, A., Minorsky, P, V., Jackson, R, B. (2015). Seed Plants. In: Wilbur, BBiology A Global Approach. 10th ed. Essex: Pearson. p707.
  2. Sunderland, T., Powell, B., Ickowitz, A., Foli, S., Pinedo-Vasquez, M., Nasi, R. and Padoch, C. (2013). Food security and nutrition: The role of forests. Center for International Forestry Research. Discussion Paper, p1-20.
  3. Met Office. (2017).Food Insecurity Climate Change. Available: http://www.metoffice.gov.uk/food-insecurity-index/. Last accessed 18th March 2017.
  4. CO2 (2017). Earth’s CO2 home page. Available: https://www.CO2.earth/earths-CO2-main-page. Last accessed 20th March 2017.
  5. Drake, B, G. and Gonzàlez-Meler, M, A. (1997). More Efficient Plants: A Consequence of Rising Atmospheric CO2?.Annual Review of Plant Physiology and Plant Molecular Biology. 48, p609-639.
  6. Taylor, G., Ranasinghe, S., Bosac, C., Gardner, S and Ferris, R. (1994). Elevated CO2 and plant growth: cellular mechanisms and responses of whole plants. Journal of Experimental Botany. 45 (Special Issue). P 1761-1774
  7. Long, S, P., Ainsworth, E, A., Rogers, A. and Ort, D, R. (2004). Rising Atmospheric Carbon Dioxide: Plants FACE the Future.Annual Review of Plant Biology. 55, p591-628.
  8. Nelson, G, C., Rosegrant, M, W., Koo, J., Robertson, R., Sulser, T., Zhu, T., Ringler, C., Msangi, S., Palazzo, A., Batka, M., Magalhaes, M., Valmonte-Santos, R., Ewing, M. and Lee, D. (2009). Climate Change: Impact on Agriculture and Costs of Adaptation.International Food Policy Research Institute. Available at: http://www.fao.org/fileadmin/user_upload/rome2007/docs/Impact_on_Agriculture_and_Costs_of_Adaptation.pdf. Last accessed 19th March 2017
  9. Myers, S., Zanobetti, A., Kloog, I., Huybers, P., Leakry, A., Bloom, A., Carlisle, E., Dietterich, L., Fitzgerald, G., Hasegawa, T., Holbrook, N., Nelson, R., Ottman, M., Raboy, V., Sakai, H., Sartor, K., Schwartz, J., Seneweera, S., Tausz, M. and Usui, Y. (2014). Increasing CO2 threatens human nutrition. Nature, 510, p139-142
  10. Fraser, E. (2014). Feeding Nine Billion Video 6: Climate Change and Food Security. Available: https://www.youtube.com/watch?v=cYq2elstFWQ. Last accessed 18th March 2017.


Old Macdonald Overfarmed: How Increasing Global Agriculture leads to Deforestation

Posted on by Kieran Woof

The Rainforests are taking the hit from our need to eat…

Almost anyone could tell you that the world’s population is increasing – and rapidly so. Naturally, this requires us to produce more and more food with which to supply all of these new faces.

However, the constant expansion of farms leads to the constant decline of forest areas, which in turn causes detrimental effects on our environment as a whole. The main region affected by these practices is the Amazon Rainforest, well known for housing around half of all the species in the entire world, as well as acting as one of Earth’s biggest Carbon sinks.

This means that its destruction will lead to a huge reduction in biodiversity, as well as releasing vast amounts of trapped Carbon Dioxide into the atmosphere, which then contributes to Global Warming. As well as the pollution aspect, deforestation may also lead to the total extinction of many tree species. This may be caused by directly chopping these trees down, or by the reduction in animals which disperse the seeds, via eating the fruit they produce (Montoya, 2008).

Image result for rainforest deforestation for farming
Farmland is rapidly encroaching on our planets forested areas (Source: Emaze)

So how big is the problem?

It has been estimated that around 350 Million Hectares of Tropical Rainforest has been converted for other land use. (Lal, 2008) Furthermore, 91% of all land deforested in the Amazon since 1970 has been used for livestock pasture! (FAO, 2006). By Converting this land, not only are we losing trees in the long term, but we are also inhibiting their possible reintroduction. This is because the soil cleared for farming often rapidly degrades due to reduced stability and intense rainfall (Kibblewhite, 2008)

The problem here is that we cannot allow people to go without food in order to save our planet’s trees. What needs to change instead is the farming technique. In farm areas bordering rainforests, the method of farming is much more likely to be expansive rather than intensive (López-Carr, 2013). This essentially means that farmers focus on growing as much of the crop as possible, rather than trying to obtain more successful growth from a smaller patch. Essentially, this leads to a lot of land being wasted, with neither tropical forests or crops actually growing on it!

So what does the Future Hold?

However, there are reasons to be optimistic! A key success story in attempts to reduce deforestation, whilst keeping high crop production, is seen in the Soybean industry. This used to be seen as a major detrimental industry to the Amazon Rainforest. However, following boycotts from several large companies, a 2015 study showed that only around 1% of all soybean production had come as a result of deforestation, despite the industry expanding over 1.3 million hectares! (Garrett, 2016).

The Soybean – An unlikely success story (Source: Plant Village)

If this technique can be implemented for other farmland crops, then we can hopefully provide enough food to keep the growing population fed, as well as protecting one of the worlds most important ecological areas.

(Word Count – 485)

References

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS . (2006). Livestock’s Long Shadow: Environmental issues and Problems.

Garrett, R, Rausch, L. (2016). Green for gold: social and ecological tradeoffs influencing the sustainability of the Brazilian soy industry. The Journal of Peasant Studies. 43 (2)

Kibblewhite, M.G, Ritz, K, Swift, M.J. (2008). Soil health in agricultural systems. Philosophical Transactions of the Royal Society B: Biological Sciences. 363 (1492), 685-701.

Lal, R. (2008). Carbon Sequestration. Philosophical Transactions of the Royal Society B: Biological Sciences. 363 (1492), 815-830.

López-Carr, D, Burgdorfer, J. (2013). Deforestation Drivers: Population, Migration, and Tropical Land Use. Environment. 55 (1)

Montoya, D. (2008). Habitat loss, dispersal, and the probability of extinction of tree species. Communicative and Integrative Biology. 1 (2), 146-147.



Could Climate Change STARVE us?

Posted on by Anonymous

The planet needs YOUR help!

We all have been alarmed and warned about rising sea temperatures, melting sea ice and glaciers, but the main problem is that we could describe them on and on.. Therefore, one of the greatest challenges the earth faces in this day and age is CLIMATE CHANGE.

A photo to show the loss of vegetation as a result of climate change (http://ayalim.org/israeli-plant-species-resistant-to-climate-change/)
A photo to show the loss of vegetation as a result of climate change  Available at:(http://ayalim.org/israeli-plant-species-resistant-to-climate-change/)

An unprecedented ↑ in atmospheric CO2 and temperature can shockingly lead to:

  • Species extinction
  • Collapsing ecosystems and food chains and as a result, foreseeable shortages of food and water to the increasing global population.

One of the toughest tasks this century, is predicting the response of plants to global climate change. Thus, what is essentially happening to our plants through this unpredictable change?

Many studies have observed:

Plants will thrive with an established elevation in CO2 and temperature…

  • As more CO2 = more fixation = more photosynthesis

Bisgrove and Hadley (2002) suggest that a “doubling in carbon dioxide level can increase plant growth by as much as 50%”

  • More heat = advanced growth and seed germination

 

HOWEVER…

Agriculture sustains almost all life-forms on Earth, meaning adverse conditions, can restrict crop plants in reaching their full genetic potential of producing a high yield (Anjum et al., 2014).

(1) Heat waves, extreme temperature events are projected to become more intense, more frequent and longer lasting to what is currently been observed in recent years (Hatfield and Prueger, 2015). Consequently, when a drought occurs where the levels of heat are extreme, the growth of a plant will rapidly decrease due to the high level of moisture loss. Furthermore, although water is essential for the functioning of virtually every plant on the planet, too much water (as a result of a storm… which we all can undeniably find exciting!) can in fact reduce the amount of oxygen in the soil, making a plant more susceptible to disease.

NOTE: Remember to stop and think, ‘this storm is not only damaging our plants, but in fact our livelihoods!’

(2) In addition, there is abundant evidence that in the long term, plants will begin to acclimate to a rise in CO2 levels. Therefore, the photosynthetic capacity becomes inhibited due to the plants being unable to utilise the additional carbohydrate that is accompanied with photosynthesis (Drake et al., 1997).

(3) Shockingly, crops of the future that are grown in a high- CO2 environment, will have decreases in the concentrations of zinc, iron and protein in grains of wheat, barley and rice (Myers et al., 2014) meaning the food in which we eat will be much less nutritious. Considering most people depend on these grains for their source of zinc and iron this can be detrimental to human health.

percentage
A graph to show the result in % reduction of nutrients from certain crops in an expected level of CO2 by 2050. (Source: NATURE)

 

If we continue to actively contribute to a world of increasing CO2 and temperature, not only are the plants on our Earth disturbed but if you stop and think: YOU yourself can be hugely affected.

A question of thought, who knows what this may cause to our future health and livelihoods?

 

 

References:

  • Anjum, N., Gill, S. and Gill, R. (2014). Plant adaptation to environmental change. 1st ed. Wallingford: CABI.
  • Bisgrove, R. and Hadley, P. (2002) Gardening in the Global Greenhouse: The Impacts of Climate Change on Gardens in the UK. Technical Report. Oxford: UKCIP.
  • Drake, B., Gonzalez-Meler, M. and Long, S. (1997). MORE EFFICIENT PLANTS: A Consequence of Rising Atmospheric CO2?. Annual Review of Plant Physiology and Plant Molecular Biology. 48(1), pp.609-639.
  • Hatfield, J. and Prueger, J. (2015). Temperature extremes: Effect on plant growth and development. Weather and Climate Extremes, 10, pp.4-10.
  • Myers, S., Zanobetti, A., Kloog, I., Huybers, P., Leakey, A., Bloom, A., Carlisle, E., Dietterich, L., Fitzgerald, G., Hasegawa, T., Holbrook, N., Nelson, R., Ottman, M., Raboy, V., Sakai, H., Sartor, K., Schwartz, J., Seneweera S., Tausz, M. and Usui, Y. (2014). Increasing CO2 threatens human nutrition. Nature, 510(7503), pp.139-142.

Word Count: 492

 

 



Are plants on their way to killing us?

Posted on by Charlotte Alanine

          Have you ever noticed how much easier it is to breathe on a jog through a luscious park or a woodland compared to the inner city? This is because the air we breathe comes from the photosynthetic process plants provide. In this reaction, plants extract energy from carbon dioxide (CO2) combined with sunlight as well as other organic soil materials and release Oxygen (O2) as a by-product which we then benefit from.

 

         Photosynthesis under increasing CO2

          Each year since 1959, approximately half of the CO2 emissions we produce linger in our atmosphere (Le Quéré, et al., 2009). With atmospheric levels of CO2 on the rise as a result of our activities, the logical outcome would be that plants have additional CO2 to photosynthesise, allowing for more oxygen for us, right? Indeed, short-term increases have no negative impacts on photosynthesis. In fact, a study suggested they became more efficient at recycling CO2 (Besford, et al., 1990) as demonstrated in the positive feedback photosynthesis and growth of P.cathayana (Zhao, et al., 2012). However, under long-term carbon dioxide exposure, plants lost all photosynthetic gain (Besford, et al., 1990). Other studies have investigated the effects of increasing CO2 levels on plants and it has recently been found that previous models may have overestimated  the ability of plant “sinks” to make use of the additional human-related carbon. A “sink” is a location where carbon dioxide accumulates and is absorbed by plants much like running water down a sink.

 

From carbon sinks to carbon sources

        In 1991, Arp projected that plants in the field would not experience a decrease in photosynthetic abilities as a result of atmospheric CO2 increase. However, more recently in 2015, Wieder et al. reported that photosynthetic processes were limited by nutrient availability, in which phosphorus and nitrogen (Aranjuelo, et al., 2013) were the main limiting factors.

Figure 1. Modelling of changes in mean terrestrial carbon storage from an initial record 1860-1869 (top) to the 2100 projection with limited nitrogen and phosphorus (bottom). Source: Wieder et al. (2015)
Figure 1. Modelling of changes in mean terrestrial carbon storage from an initial record 1860-1869 (top) to the 2100 projection with limited nitrogen and phosphorus (bottom). Source: Wieder et al. (2015)

          In addition, their models projected that by 2100, plants which were once considered sinks may actually be turning into carbon sources (fig.1). This means they could be emitting more carbon than they absorb as a result of increasing carbon dioxide in the air in combination with the insufficient amounts of other organic materials (nitrogen, phosphorus, minerals, etc.) necessary for photosynthesis and consequently accelerating the rate of climate change which is bad news for us. Plants will essentially be slowly suffocating us as we rely on them for clean air.

 

 

 

A threat to food security

          Likewise, as a result of intensifying agriculture, soils are becoming increasingly eroded. For one, this means they are unable to store and process atmospheric carbon as efficiently and there is a lack of nutrients made available to plants (Lal, et al., 2008). This, coupled with the higher concentrations of CO2, poses a great threat to major crop plants such as oilseed rape (Franzaring, et al., 2011) and wheat (Uddling, et al., 2008). In laboratory studies, these crop plants tended to reduce the quality and quantity of their seeds in high concentrations of CO2.

          Emissions are not only posing a threat to a plant’s capacity to recycle air but also put our food security at risk.

References

Aranjuelo, I., Cabrerizo, P., Arrese-Igor, C. & Aparicio-Tejo, P., 2013. Pea plant responsiveness under elevated [CO2] is conditioned by the N source (N2 fixation versus NO3 – fertilization). Environmental and Experimental Botany, Volume 95, pp. 34-40.

Arp, W., 1991. Effects of source-sink relations on photosynthetic acclimation to elevated CO2. Plant, Cell and Environment, Volume 14, pp. 869-875.

Besford, R., Ludwig, L. & Withers, A., 1990. The Greenhouse Effect: Acclimation of Tomato Plants Growing in High CO2, Photosynthesis and Ribulose-1, 5-Bisphosphate Carboxylase Protein. Journal of Experimental Botany, 41(8), pp. 925-931.

Franzaring, J., Weller, S., Schmid, I. & Fangmeier, A., 2011. Growth, senescence and water use efficiency of spring oilseed rape (Brassica napus L. cv.Mozart) grown in a factorial combination of nitrogen supply and elevated CO2. Environmental and Experimental Botany, Volume 72, pp. 284-296.

Lal, R. et al., 2008. Soil erosion: a carbon sink or source?. Science, 319(5866), pp. 1040-1042.

Le Quéré, C. et al., 2009. Trends in the sources and sinks of carbon dioxide. Nature geoscience, 2(12), pp. 831-836.

Uddling, J. et al., 2008. Source-sink balance of wheat determines responsiveness of grain production to increased [CO2] and water supply. Agriculture, Ecosystems and Environment, Volume 127, pp. 215-222.

Wieder, W., Cleveland, C., Smith, W. & Todd-Brown, K., 2015. Future productivity and carbon storage limited by terrestrial nutrient availability. Nature, 8(6), pp. 441-445.

Zhao, H. et al., 2012. Sex-related and stage-dependent source-to-sink transition in Populus cathayana grown at elevated CO2 and elevated temperature. Tree Physiology, Volume 32, pp. 1325-1338.

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Denial isn’t just a river in Egypt

Posted on by Sarah Hill
bog-river
Stream in the Redwood National Park

Humans (Homo sapiens) have been on this planet for at least 200,000 years (Hopkin, 2005) and throughout this time we have caused large changes to the river network. These modifications have occurred for many reasons;

  • Flood defence
  • Irrigation
  • Transport of goods
  • Drinking water
  • Power
  • Sanitation

But any changes made to a system has knock on effects to the organisms living there through changes in their biotic, living, and abiotic, non-living, environment. Human mediated change is no exception.

 

Pollution

As a result of human infrastructure and urbanisation rivers have become polluted with PAHs and heavy metals that have been washed off hard surfaces, such as roads. Industrialisation releases sulphur dioxide and nitrous oxide into the atmosphere which enters the rivers through acid rain. Sewage is also discharged into rivers in some areas, such as from houseboats and canal boats, which reduces the amount of oxygen available in the water for the organisms. Agriculture uses fertilisers and chemicals which, through the process of leaching and run-off, can end up in the river system. Pesticides and herbicides will kill insects and plants in the river system. Other chemicals are toxic to organism, as ammonia is to fish (Ip et al, 2001). Increasing nutrients in the rivers can result in eutrophication:

 

Flow modification

Some river channels have been deepened and widened to prevent flooding, resulting in their flow becoming faster. Flow has also been slowed in some rivers through the addition of dams, which have been built to supply drinking water and power to the public. Altering the flow of a river has wide spread effects on the ecosystem as it changes the abiotic and biotic composition. A slow flow results in higher temperatures (Dickson et al, 2012) and more sediment deposition (Christiansen et al, 2000) than a fast flow. Dams not only restrict the movement of the water but also organisms, which is a massive problem for migrating species such as eels and salmon. Irrigation results in a reduced water level which can be adverse for larger fish species and also alters the velocity of the flow.

blog-irrigation
Typical structure of surface irrigation

 

Introduced species

Introductions to rivers can be both intentional, eg for fishing, or unintentional, eg from the underside of boats. Only 1% of introduced species become invasive, affecting native species (Jeschke and Strayer, 2005), by competing for resources, preying on native species or introducing harmful diseases and parasites. This is a major problem in river systems due to their connectivity which mitigates the migration of these species to other reaches of the river making control and eradication difficult.

 

Harvesting

Excessive commercial harvesting of fish and shellfish in rivers can drastically reduce their numbers and the number of species. Eel and white bait numbers have declined significantly in the Waikato River, New Zealand, since the 1970s for this precise reason (Chapman, 1996). Reducing the population size of a particular species effects those that feed on them, such as other fish, birds, mammals and even reptiles.

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Snake eating a fish in the water and puffin with fish in its beak

 

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References

Chapman M.A. 1996. Human impacts on the Waikato River system, New Zealand. GeoJournal. 40, 85-99.

Christiansen T., Wiberg P.L. and Milligan T.G. 2000 Flow and sediment transport on a tidal salt marsh surface. Estuarine, coastal and shelf science. 50, 315-331.

Dickson N.E., Carrivick J.L. and Brown L.E. 2012. Flow regulation alters alpine river thermal regimes. Journal of hydrology. 464, 505-516.

Hopkin M. 2005. Ethiopia is top choice for cradle of Homo sapiens. Nature news. doi:10.1038/news050214-10.

Ip Y.K., Chew S.F. and Randall D.J. 2001. Ammonia toxicity, tolerance, and excretion. Fish physiology. 20, 109-148.

Jeschke J.M. and Strayer D.L. 2005. Invasion success of vertebrates in Europe and North America. PNAS. 102, 7198-7202.



DROUGHT: Destroying the Central Valley Wetlands, but what about all the Wild Life?

Posted on by Sophie Cox

Welcome to California, the place of sunny dreams, but this dream in the case of waterfowl has become a terrifying nightmare.  The state of wetlands in the Central Valley was described as “discouraging” back in 1949 by Day, but it’s safe to say it’s got a lot worse, with over 95% now gone or threatened,  something tells me we should have been paying more attention 65 years ago!

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The ironic tourist welcome is not so welcoming to migatory birds. (http://www.startribune.com/summer-time-out-from-heat-humidity/268977201)

The ‘Pacific Flyaway’ is the migratory pathway millions of birds undertake every year from their northern breeding grounds in Canada and Alaska.  It’s believed up to 60% of migratory birds stop off in the Central Valley for the summer time (Dasman, 1966).

But surely people aren’t the problem ?

Drought is a massive problem throughout the world but just to add to the pressure of an already warm climate let’s add the stress of agriculture and urban growth. California is the leading agricultural state in the USA (Mills, 1997) and with this, demand for water is high and legislation has made this a priority over wildlife.

Smart or Stupid, well that’s a personal opinion… but with only 25% of central valley having an “adequate water supply” we then go and take 87% of this and use it for irrigation (Kahrl, 1979). Oh and don’t forget the pesticides sprayed all over the crops polluting the water.

No wetlands, what’s the problem ?

So, wetlands are disappearing, but they aren’t that critical to a community? Wrong!

The Central Valley is ‘Feeding Ground Central’ for over 5 million bird, but with the loss of wetlands. The question is where do all these birds find food?

The options

They can overcrowd in the remaining wetlands, however, food limitations occur as early as mid winter/ early spring (Petrie et al., 2016). Flies and insects struggle to have successful hatching due to lack of stagnant water, and those within the sediment and plants desiccate. Meaning food sources of the waterfowl are greatly effected by this fragmentation.  Oh and to top it off the rate of disease sky rockets with overcrowding. Cases have documented die offs of over quater of a million ducks as a result of avian diseases (Hunter et al., 1970).

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Drought stricken wetland, no birds or food in sight! (Photo by Patrick Dove/ San Angelo Standard-Times via AP)

Or

They can settle on agricultural land, shifting their habitat and dietary requirements. So it’s all fine, right? 50% of these migratory birds now rely on waste rice/grain crops for their energy source instead of plants and insects previously found in wetlands, they have learnt to exploit a new niche. Great!

banner_trumpeterswan
Swans feeding on Agricultural Land (Photo by Markus Merkens)

 So the community has changed, they found food so it’s all fine?

This really would be the ideal situation, Sadly, despite over coming dispersal barriers by flight, drought has greatly restricted the habitat and has drastically changed the community composition by desiccation and lack of hatching success of insects and flowering plants. The adaptation of diet change to exploiting crops still posses great risk as everything is still water dependant.

The effects on the community are already drastic but how far could drought really push the wildlife all over the world?

References

Day, A.M. (1949) North American Waterfowl. The stack-pole Co., Harrisburg, Pennsylvania, pp.363

Dasmann R.F. (1966) The Destruction of California, Collier Books, New York City, 10tth pp.203-223

Hunter, B.F., Clark, W.E., Perkins, P.J., Coleman, P.R. (1970) Applied Botulism Research Including Management Recommendations- a progress reports. California Department of Fish and Game, Rancho Cordova, California, USA. pp.37

Kahrl, W.L. (1979) The California Water Atlas, Governor’s Office of Planning and Research in cooperation with the California Department of Water Resources, Sacramento, California

Mills, P.K. (1997) Correlation Analysis of Pesticide Use Data and Cancer Incidence Rates in California Counties. Archives of Environmental Health : an international Journal. 53(6), pp.410-413

Petrie, M., Fleskes, J., Wolder, M., Isola, C., Yarris, G. and Skalos, D. (2016). Potential Effects of Drought on Carrying Capacity for Wintering Waterfowl in the Central Valley of California. Journal of Fish and Wildlife Management, 7(2), pp.408-422.

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Believe it or not… CLIMATE CHANGE WILL TRUMP U.S.!

Posted on by Hannah Lesbirel

By Hannah Lesbirel student at University of Southampton

You’ve all seen images of famine and the effect of crop failure on families across the globe. Have you ever pictured that being you? No, me neither.

Surely that can’t happen in the USA- “The greatest country in the World”- people say?

Queues for food rations. This is happening somewhere in the world right now! Imagine, this could be you if nothing is done to reduce the impacts of climate change. Source: http://answersafrica.com/starvation-and-famine-in-africa.htm
Queues for food rations. This is happening somewhere in the world right now! Imagine, this could be you if nothing is done to reduce the impacts of climate change. Source: AnswerAfrica

Some experts argue the increase in CO2 levels, associated with climate change, may in fact contribute to gains in some crops, in some regions of the world. Surely more CO2 means more photosynthesis, right?

However, the negative impacts associated with climate change are expected to reverse the potential benefits (Nelson et al., 2009). Climate change indisputably impacts: global temperatures, frequency and intensity of extreme weather events, CO2 levels and water availability, and without availability of sufficient water and nutrients photosynthesis can’t thrive (Nelson et al., 2009; Hatfield et al., 2011).

The video below summarises the limiting factors of photosynthesis and how they could be influenced by the changing environment.

Temperature Variability

The rate of plant development is primarily influenced by temperature, impacting (Hatfield and Prueger, 2015);

  • Pollen viability
  • Fertilisation
  • Water requirements
  • Grain and fruit formation
  • Length of life cycle

All plants have an optimum temperature in which photosynthesis takes place, too high and enzymes are denatured and too low the catalytic efficiency of these enzymes are reduced. Additionally, higher temperatures are known to encourage weeds, pests and disease.  The figure below shows the predicted temperature due to climate change globally by 2050 (Nelson et al., 2009). If this rise in temperature is to continue, this will reduce crop yields across the globe.

Source: Nelson et al., 2009
Predicted increase in global temperatures by 2050. Source: Nelson et al., 2009
picture1
Once luscious fields becoming barren due to decreased yields as a results of climate change. Source: Crated and Nature 

With warmer temperatures predicted along with the increased probability of extreme temperature events, plant productivity is at serious RISK! Estimations show a significant decline in yields, of between 80-90%, compared to ‘normal’ conditions (Hatfield and Prueger, 2015).

Changes in Precipitation

The concern of rising global temperatures, will be proliferated by changes in precipitation. Increasing the likelihood of crop failure and long term production decline (Nelson et al., 2009).

Despite uncertainty in precipitation change, under future climate change scenarios, the impact of excess and deficit amounts of soil water will be negative for crop production, either drowning or starving the crops of water (Hatfield et al., 2011).

It’s been said that “stronger interannual variability with more extreme year-to-year climate variations…[means] farmers are unable to tune their cropping systems to optimize resources (Bannayan et al., 2010).”

Not only will this have a major impact on human health and well-being. Agriculture contributes over $300 billion to the U.S. economy each year; think of the impact this may have on your health and livelihood.

Decline of Global Markets

On a more global scale, the potential decline in production will reach international levels, as U.S. farms supply 25% of all grain (soybean, wheat and maize) on the global markets (Nelson et al., 2009; USEPA, 2016).

screen-shot-2017-03-06-at-13-24-35
The cycle that could follow the decline in grain production (Nelson et al., 2009).

The ‘domino’ effect of a decline in grain productivity is incomprehensible. The cycle that could follow is shows to the right.

Could we be building a wall between us and future generations? Progress is needed to prevent this shocking reality.

Read more information about the impact of Climate Change on global agriculture from the FAO report on Climate change: Impact on Agriculture and Costs of Adaptation.

 

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Read More:

http://ecoethics.net/cyprus-institute.us/PDF/Rosensweig-Food-Supply.pdf

http://bioenv.gu.se/digitalAssets/1432/1432197_fantahun.pdf

http://www.pnas.org/content/106/37/15594.full