Little monkeys need lots of space

This charming little creature is a White headed marmoset or "Sagui" (Callithrix geoffroyi). Tolerant of humans, they are often seen by tourists and will readily take pieces of fruit in their little hands. Classified as Least Concern (LC) on the IUCN Red List and in appendix II of CITES, surely conservation is no problem? Well, more or less.

Historically many were taken from the wild as pets, their very tolerance of man acting against them. This is tightly controlled these days, but their numbers are still decreasing. In the 21st century loss of habitat is the major problem, or more specifically, fragmentation of habitat. You might think that 20 forests of 1 km sq.would hold the same number of monkeys as 1 of 20 km sq. Indeed, given that predators tend to require much larger ranges and so are less likely to occur in small pockets, you might assume there would be more monkeys. You would be wrong (Chiarello & de Melo, 2001). There are various reasons.

a) Long term of course, small populations lack enough genetic diversity to stay healthy, but there are more immediate reasons.

b) Small forest fragments tend to favour trees and shrubs which are forest edge species, with proportionally less canopy or forest interior species (Cardoso da Silva and Tabarelli, 2000). Unfortunately, these are the very ones that produce the most fruit. Thus small monkeys, which tend to need a lot of fruit, suffer accordingly. In the same way, large fruit eating birds like macaws and toucans tend to be absent from isolated forests less than 250 hectares (Willis 1979).

Our little saguis are quite adaptable, and eat a lot of tree gum and insects (and anything really), so suffer less than fruit eating specialists, but it still cuts down their options. And they have another problem.

c). Small fragments may have fewer large fragments, but they still have plenty of cats, either native or feral from surrounding farm and residential land. Saguis and other small monkeys are especially susceptible to cats. They do their best, mobbing them and screeching, but that's not always enough. As an aside, it has been shown that being part of a "mob" actually reduces rather than increases monkey stress - it is tempting to extrapolate that to humans!

Driving through a landscape of fields and copses may appear more "natural" than a prairie of wheat or sugar cane, and it is, but maybe not that much more.

References
Cardoso da Silva JM, & Tabarelli M (2000). Tree species impoverishment and the future flora of the Atlantic forest of northeast Brazil. Nature, 404 (6773), 72-4 PMID: 10716443
Chiarello, A.G., de Melo, F.R. (2001). Primate population densities and sizes in Atlantic forest remnants of northern Espirito Santo, Brazil. International Journal of Primatology, 22, 379-396.

Willis, E.O. (1979). The composition of avian communities in remanescent woodlots in southern Brazil. Papéis Avulsos de Zoologia, São Paulo, 33, 1-25. 

Four continents and a fish

As a child in the seventies, I remember clutching my grandfather’s arm and marvelling at Tilapia being reared in a shallow pond in his land in a South Indian village. Many years later, one summer in the late nineties, in an oriental store in Ohio, USA, I was introduced to a packet of frozen fish which turned out to be Tilapia. Needless to say, I enjoyed it much and felt that it was one of the most delicious fishes I had ever eaten.

Fast forward to 2010… in a lakeside restaurant by the Sea of Galilee, in Israel, we were served St. Peter’s fish which was delectable. St. Peter’s fish is so named after the account in the gospel of St. Matthew where Jesus asks His disciple Peter to catch a fish, open the mouth of the fish, and find the coin that is to be paid as taxes. It turns out that St. Peter’s fish was indeed Tilapia. The species of the fish in Israel carries its small young in its mouth until large enough to survive on their own. The fish also seems to have a penchant for shining objects and is known to pick up small pebbles and bottle caps from the lake floor. In the idyllic restaurant by the Sea of Galilee, our tour guide repeatedly threw pieces of bread into the water and we could see Tilapia shoaling in and catching the food, vying with hoards of kittens and cats perched on the rocks that had learnt to traverse the shallow waters. Later I learnt that St.Peter’s fish has been used in small-scale low-technology commercial or subsistence fishing practices in that area for thousands of years.

I had forgotten all about Tilapia until recently I read the correspondence in Nature by Vitule et al arguing against the proposed law that, if implemented, would lead to the culture of invasive non-native species of Tilapia and other fishes in cages in dammed areas in Brazil.

The name ‘Tilapia’ is used loosely to describe over hundred species of cichlid fish from the tilapine cichlid tribe. Cichlids are most diverse in Africa and South America. The native cichlids in Asia are restricted to very few species in Israel, Iran, India, Syria and Sri Lanka. Other cichlids include fishes commonly grown in aquariums like the angel fish and discus. Tilapia seems to be highly resilient in the nature of its habitats-living in ponds, streams, lakes and rivers. Due to their ease of farming, size, protein content and taste they are among the top ten fish used in farming. Tilapia meat which is a good protein source, low in saturated fat, and calories does not accumulate mercury. Tilapia can effectively controls algae which they feed upon and replaces the need for the use of chemical algaecides. In Africa, they control pests such as mosquitos. Whilst native species are rich in nutrients, farmed species have low levels of omega 3 fatty acids due to their diet. Additionally, farmed fish are fed with hormones such as testosterone which may have endocrine disrupting effects in the food chains.

Whilst tilapia require warm waters to survive and cannot live in natural temperate habitats (indicating that farming of tilapia in controlled conditions may not disrupt the native species if accident release does take place), such a situation could be catastrophic in the long run in the tropical areas by leading to the disruption of native fish species. In Lake Victoria, introduction of the Nile Tilapia led to the disappearance of two native species. The alien species has a higher growth and fecundity rate compared to the native species. Rightly, Tilapia is listed in IUCN’s compendium of invasive alien species.

Farming of native species of Tilapia is beneficial as long as it is subsistence and sustainable farming. However, current aquaculture practices of non-native fishes often involves aggressive farming methods. Further culture of non-native species in cages in natural water bodies might pose significant risk to containment which could be compounded in sub-tropical and tropical environments where escape would lead to colonisation and disruption of the already fragile ecosystems. J.R.S. Vitule, the lead author of the correspondence in Nature from Laboratório de Ecologia e Conservação, Paraná, Brazil, whose research focuses on the conservation of the endemic freshwater fishes of the Atlantic rain forest and the management of non-native fish species that threaten their survival, says ‘Fish escapes are inevitable, and cage aquaculture may create a constant flow of propagules into the wild, establishment, spread and invasions’ (Personal correspondence with Dr. Vitule). Other issues relate to the release of nutrients such as fish feed that can lead to water pollution and also potential endocrine disruption (Ortiz -Rodas et al, 2008), a topic requiring further investigation. The debate continues……

References:

http://www.worldwildlife.org/what/globalmarkets/aquaculture/dialogues-tilapia.html

http://www.goisrael.com/Tourism_Eng/Tourist%20Information/Discover%20Israel/Geographic%20Regions/Pages/Lake%20Kineret%20(Sea%20of%20Galilee).aspx

http://www.aquaticcommunity.com/lakevictoria/plight.php

http://www.fao.org/DOCREP/003/V5930E/V5930E02.htm

Vitule, J. (2012). Ecology: Preserve Brazil's aquatic biodiversity Nature, 485 (7398), 309-309 DOI: 10.1038/485309c

Rodas-Ortíz, J., Ceja-Moreno, V., Chan-Cocom, M., & Gold-Bouchot, G. (2008). Vitellogenin Induction and Increased Plasma 17β-Estradiol Concentrations in Male Nile Tilapia, Oreochromis niloticus, Exposed to Organochlorine Pollutants and Polycyclic Aromatics Hydrocarbons Bulletin of Environmental Contamination and Toxicology, 81 (6), 543-547 DOI: 10.1007/s00128-008-9556-9

Image source: Sarah Stephen (image shows a typical St. Peter’s fish lunch in the Sea of Galilee)

When introductions go bad

My first sighting of the red squirrel was in Camperdown Park in Dundee in 2003. I remember that scene vividly. I had since tried desperately to see this elusive animal again but to no avail, save a brief sighting, again in Camperdown Park, in Autumn 2010. This is because although red squirrel, which is native to UK and  is  protected in Europe, is outnumbered by its foreign relative, the grey squirrel that was introduced to the UK from America. Grey squirrel has several competitive advantages including its resistance to squirrel parapox virus which is fatal to the red (grey squirrels are vectors), increased fecundity, and greater ability to digest a wider variety of food. In fact, the future of the red squirrel in the British Isles is rather precarious. The Forestry Commission estimates that there there are only 140,000 red squirrels compared to over 2.5 million greys.

Recently during a holiday near Lake Geneva, Switzerland, I encountered 2 red squirrels and 1 black squirrel  (resembled the red squirrel with respect to the ear tufts, but with a black/grey rather than red coat). You can see a video here in Youtube:  http://www.youtube.com/watch?v=g4SqcK9CME8

There is a lot of debate on how the introduction of alien species can affect the native species and tilt ecosystems, but studies indicate that certain ecosytems could be more vulnerable that others. As early as 1958, Charles Elton claimed that ecosystems with higher species diversity were less subject to invasive species as there are  fewer available niches. A recent paper by Eisenhauer et al shows that species diversity could stabilise communities during invasions. It appears as if biodiversity of ecosystems provides increased resilience against onslaughts including that by foreign invaders. Caution should be exercised when foreign species are introduced. In light of these observations, a  proposed law in Brazil is of importance. A recent correspondence in Nature by Vitule et al (May 2012) warns of the repecussions of a new law that, if approved, would allow farming of foreign fish species in cages. The fishes that are being considered for introduction are tilapia and carp. The authors warn that the indigenious aquatic ecosystem would be disrupted if these  introduced species were to escape and would jeopardise the aquatic biodiversity which is already fragile due to  human activities such as pollution and construction.

References:
Vitule JR (2012). Ecology: Preserve Brazil's aquatic biodiversity. Nature, 485 (7398) PMID: 22596145
Eisenhauer N, Scheu S, & Jousset A (2012). Bacterial diversity stabilizes community productivity. PloS one, 7 (3) PMID: 22470577
http://www.europeansquirrelinitiative.org/the_threat.html


Red Squirrel image source: Sarah Stephen

Dams on the Xingu

On June 1st Dilma Rousseff, the President of Brazil, controversially gave permission for the company Norte Energia to begin building a hydroelectric dam on the Xingu river in the northern state of Para. This follows the granting of a provisional licence in January by the previous president, Lula da Silva, to begin land clearance and road construction, and years of court cases. A total of eleven cases have been filed against the project by the Federal Public Prosecutor, over various irregularities, the last being overturned in February.

Artists impression of the dam

The Belo Monte dam complex will in fact consist of 3 dams. The first, Pimental Dam, will be 36 metres tall, over 6 kilometres long, and will create a lake with a surface area of 129 square miles. This will supply one power station. Two canals will channel water down to another reservoir created by the Belo Monte dam, which will supply another power plant. The Belo Monte dam will be 90 metres tall but only 3.5 kilometres wide, and create a lake of 42 square miles. The whole complex is expected to cost 16 billion US$, with power cables costing a further US$ 2 billion.

For good or ill this is going to affect a lot of people.

Advantages

On the positive side, an immense amount of energy will be generated, the Belo Monte dam is the third largest hydroelectric project in the world after the Three Gorges Dam in China and the Itaipu dam between Brazil and Paraguay. Itaipu already supplies 19% of Brazil's energy needs and virtually all of Paraguay's. The planned capacity of Belo Monte is unclear, as we will see below, but it is claimed by EletroBras, the state electricity company to at least supply the state of Para (population 7.5 million). This of course is all power that would otherwise have to generated by fossil fuels or nuclear energy. Once built, the running costs will be minimal, and electricity will be provided continuously (well, again, see below) for over 50 years. It's not true that will be no carbon emissions. Studies of other Brazilian dams have found that as the water level falls and rises every year, vegetation flourishes in the tropical climate, only to be submerged and decay, releasing methane. But the amount is probably much less than an equivalent coal fired power station.

The location, with a natural drop in elevation, allows the use of a relatively low wall, and thus smaller reservoir, to generate power requiring a much bigger reservoir elsewhere. Thus, the argument goes, if you are going to have a dam, this is the place to have it.

Aluminium at Barcarena

Approximately 18,000 jobs will be created by the construction project, and another 25,000 indirectly, although of course most of these will cease when construction is finished. More long term will be aluminium processing plants powered by the dam, with a view to export to China. The planned Brazilian-Chinese bauxite processing plant at Barcarena, Para, will be the largest in the world. There are also existing Japanese and American plants which will be expanded. This gives Brazil a much higher value export product than simple ore.

Disadvantages

The disadvantages can be divided into social, practical and environmental.

Social
For a start over 20,000 people will be directly displaced. These people will need to be resettled. Then there are the people downstream, mainly from the Juruna and Arara tribes. As they will not be directly affected they have not been offered resettlement, but as the river is a major food supply and transport network, falling levels will possibly cause displacement anyway. This will probably be exasapated by increased levels of water borne diseases from more stagnant pools. In fact, the vast majority affected by this project will be indigenous peoples, and this has aroused a lot of resentment, and threats of violence.

In contrast, an estimated 100,000 migrants from other parts of Brazil will enter the area. It is not clear what infrastructure will be in place to support them.

Practical

A number of studies have cast doubt on the economic viability of the project. The ex-President of Sapesp, the Sao Paulo state water company , has claimed it will be one of the most inefficient hydroelectric power projects in Brazilian history. Mainly because of the seasonal nature of water supply via the Xingu river, so that it will be at 30% capacity or less from June to October.
Actually there is a solution to that - another dam. Although the intention is vehemently denied, a further dam at Altamira up stream would create a 2,000 sq mile lake and a year round water supply, making the whole project much more viable. It would also displace another estimated 25,000 people. The long term intention to build another dam would be easier to dismiss if the turbine capacity of the planned power stations were not considerably more than the likely water flow.

Another artists impression

Environmental

Construction of the dam required an environmental licence from IBAMA, the Brazilian environmental agency, and this was granted in February 2010. Controversially. Two IBAMA presidents and at least two senior officials have resigned claiming undue government pressure to approve the licence. Even now, the licence is technically provisional with many requirements yet to be met before a full licence can be granted, but that is moot as a judge has ruled that work can commence without a full licence.

Large amounts of forest will inevitably be lost. One concern is the loss of biodiversity as a number of species are found only within the area affected by the dam, and it is extremely unlikely they would survive the drying out and/or flooding of their habitats. This apparently includes the Plant eating piranha Ossubtus xinguense (actually it's omnivorous and will eat worms and shrimps) and the Xingu poison dart frog Allobates crombie, amongst others.

What is certain is that it is not just the area under the construction that will be affected. The influx of tens of thousands of migrants will consume a huge area of forest for building of homes and roads, and then farm land to support them.

Further Reading

Fearnside, P. (2006). Dams in the Amazon: Belo Monte and Brazil’s Hydroelectric Development of the Xingu River Basin Environmental Management, 38 (1), 16-27 DOI: 10.1007/s00267-005-0113-6

Sousa Júnior, W.C. and Reid, J. 2010. Uncertainties in Amazon hydropower development: Risk scenarios and environmental issues around the Belo Monte dam. Water Alternatives 3, 249-268

Global Forest Resources Assessment 2010

The Food and Agriculture Organisation’s Global Forest Resources Assessment 2010, which surveyed 233 countries, stated yesterday (25th March)that the global rate of deforestation has slowed down over the past decade, from 16 million hectares per annum in the 1990s to 13 million hectares per annum in the 2000s. Natural forest progression and afforestation programmes (mostly in China, India, Vietnam, and the US) have resulted in an addition of more hectares of new forests per annum (Asia had a net gain of 2.2 million ha per annum in the 2000s). Two countries which had the highest deforestation rates in the 1990s, Brazil and Indonesia, have significantly reduced this in the 2000s: from 2.9 million ha p.a to 2.6 million ha p.a in Brazil and from 1.9 million ha to .5 million ha in Indonesia). North and Central America had stable rates, whilst Europe had a slower rate of forest expansion than before. Yet, forested areas around the size of Costa Rica is being destroyed each year, mainly due to clearing lands for agriculture and natural causes. The highest net annual forests loss were in South America (4 million ha) and Africa (3.4 million ha). Primary forests (36% of total forested area) have decreased by more than 40 million ha since 2000. I have referred to some aspects of deforestation in Our Gossamer Planet, but I would like to point out the one great benefit of the forests (currently over four billion hectares)- they act as carbon sinks- absorbing and storing greenhouse gases. There’s more in ‘Biodiversity in India’ in The Ship 09/10, published by St Anne's College, Oxford. The Assessment’s findings are seminal, with 2010 being the UN-designated International Year of Biodiversity. Yet, the aim should be to reduce global annual deforestation rates to the proportions of a school’s playground, or perhaps even less!