Head in the clouds: Vulnerability of cloud forests to climate change

When I first encountered an article on science daily written about 'cloud forests', I became instantly intrigued to find out what they were as images of fluffy cloud trees flashed through my mind.

Blue cloud topped trees- only believable in fantasy. 

However, after some investigating on the internet, I came across more and more articles describing cloud forest reserves and their vulnerability to climate change in the Age of the Anthropocene. Eureeeeka! A blog topic for this weeks post was discovered.

Tropical Montane cloud forests are among the most vulnerable terrestrial ecosystems in the face of climate change (Ponce- Reyes et al. 2012).  They have restricted climatic requirements and fragmented distributions. The forests support a range of endemic species and with such a unique biodiversity it is vital this ecosystem is protected.

A cloud forest is a tropical or sub-tropical evergreen forest characterised by a low level cloud cover. They also can be called mossy forests due their abundance of ground mosses and vegetation (UNEP, n/d). The forests gain their moisture from the low settling clouds surrounding them. The plants in the canopy have  adapted to be able to extract water directly from the clouds using 'horizontal precipitation'. 

Image of mountain cloud forests with the characteristic 

fluffy cloud top. 

These forests however are heavily dependent on local climates, due to the fact they only occur within narrow altitudinal limits and therefore are extremely vulnerable to climate change. Tropical montane cloud forests are distributed 23 degrees North to 25 degrees South. Important areas of cloud forest include Mexico, Central and South America, Indonesia, Philippines and the Caribbean. 

                                Locations of Tropical Montane Cloud forests (Aldrich et al. 1997)

'12% of Mexican cloud forest is protected, however it is still not known if reserves will ensure the persistence of this special ecosystem and the biodiversity it provides a habitat for' (Ponce- Reyes et al. 2012). In Mexico, cloud forests account for 1% of land cover, but support the highest concentration of plant and animal diversity of any other Mexican ecosystem. 30% of all flowering plants in these forests are endemic to just cloud forests and around 90% of Mexican cloud forests have already been cleared for agriculture, cropping, grazing and extraction of natural products. It is worrying that with climate change the conditions needed for these spectacular ecosystems to exist will become reduced, ultimately reducing the potential expansion rate of the cloud forests. What really stuck in my mind was the statistic that 'loss of cloud forest directly attritable to climate change would lead to the extinction of 37 vertebrates restricted to this region of forest'.  Clearly, immediate action is needed and it should be an urgent priority to extend the protected areas. 

Currently the world land trust (WLT) is working with the local conservation group 'ecologic Sierra Gorga' (GESG) to save as much of this threatened habitat as possible. 

To liven up the post and provide a real insight into the Mexican cloud forests and the anthropogenic threats posed to them, have a look at the following short video. It explains the reliance on these moist rich ecosystems for various types of agriculture and what this is causing to happen to the sensitive ecosystem. 

Score Board Update: Anthropocene 6 - 3 Biodiversity 

Have a Holly Jolly christmas...

First things first, Merry Christmas! Hope everyone had wonderful day. The blog post today is going to be christmassy themed to hopefully keep you all in the spirit of christmas, at least till the new year when coursework deadlines will be deeming. To begin to set the mood, before you read on and discover the wonders of christmas holly (Ilex aquifolium) give the song a listen and dance around. Christmas day itself may have passed but the christmas holidays are still upon us.

Now we have you all in the mood, let me introduce today's topic 'English Holly' or sometimes known as 'Christmas Holly'. I did not realise that this seemingly harmless festive tradition is also a problematic invasive species in some areas such as in America and Pacific Northwest. Ilex aquifolium is a broad leaf evergreen shrub that can grow from 5-18 metres high. With its pretty waxy leaves and red berries, it has become, in Britain, to epitomise the essence of christmas. 

Image. English Holly with its poisonous red berries on the female plant. 

The holly is shade tolerant and highly competitive with other native understory plants (Boersma et al. 2006). This particular holly has escaped into forested areas where it grows in shade or sun on well drained soils. Due to the way it can grow vegetatively or by seed, it is resilient to changes in climate. It is particularly detrimental to native plants as it is a water hog, preventing sufficient water for the surrounding vegetation. With climate change, English Holly is going to be affected much like any other species on the Earth. In the IPCC 4th report, it stated that ' English Holly would see a poleward shift of the northern margin due to increasing winter temperatures' `(WWF, n/d). The same shifting is also predicted to occur with European Mistletoe (Viscum album) which is gaining altitude in response to climate change. The study reveals that the plant has climbed 656 feet in the last hundred years (National Geographic, 2010). 

Till next time, eat, drink and be merry!

Eutrophication Looming...

Freshwater habitats are disproportionally diverse compared to other ecosystems, with them only covering 1% of the world surface yet providing habitat for over 25% of described vertebrates (Kipping, 2008). It has been estimated by the ICUN that there are around 27,400 freshwater species including fish, crabs, dragonflies and plants. With such a vast biodiversity, freshwater ecosystems provide many important goods and services not only to ecology but to humans also, including building materials and  flood and erosion control. Many of the world's poorest neighbourhoods rely solely on these ecosystems. 

Since the industrial revolution, many anthropogenic activities have caused alterations in the structure and functioning of freshwater environments (Millbrook, 2009). By increasing demands of aquatic environments, eutrophication has lead to undesirable changes in freshwater biodiversity (Smith et al. 1999). Changes in land use, including land clearing for agriculture, forestry, animal husbandry and urbanisation has caused an increase in the available limiting nutrients, nitrogen and phosphorous in global biochemical cycles, that have been polluting lakes and streams worldwide (Vitousek et al. 1997). This surplus of nitrogen in terrestrial soils can move easily from land to surface water, migrating into groundwaters, increasing the toxicity (Nolan et al. 1997). With increasing human population densities, the increasing combustion of fossil fuels has been causing additional atmospheric nitrogen to enter water sources, increasing nutrient levels in many water bodies that are located near heavily populated areas. To understand how freshwater biodiversity is severely threatened by nutrient loading, it becomes vital to understand firstly, what is meant by this word 'eutrophication'. 

'Eutrophication is the process by which water bodies are made more eutrophic through an increase in their nutrient supply. This can choke rivers, lakes and other waterways by excess algae growth which has been simulated by fertilisers and poor disposal of human sewage' (Smith et al. 1999). 

Eutrophication influences the production of blue-green algae (cyanobacteria) and the growth of vascular plants in freshwater ecosystems which can effect light penetration into water bodies. The impacts are much more wide reaching than plant growth alone. Eutrophication also causes degradation of such water bodies resulting in a loss of species. (Postel and Carpenter, 1996). 

Blue-green algae (a easily observable green layer covering a fresh water source). 

In recent decades, eutrophication has been highlighted as one of the most serious environmental problems facing water managers. In Europe, this is especially seen as a highly destructive problem, hence why the European Water Framework Directive has allocated it as a important issue on their agenda (Sandergaard et al. 2007). Billions has already been invested to curb this issue by improved water treatment, however, despite this, eutrophication still remains a devastating problem in many areas. Saandergaard et al. (2007) portrays how internal mechanisms, both chemical and biological can prevent lake recovery. Such internal mechanisms include, internal loading from lake sediments (Marsden, 1989) and the 'development of zooplanktivorous and bethivorous fish in eutrophic lakes which reduces the top down control of zooplankton and phytoplankton' (Shapiro and Wright, 1984). 

Whether there is success or not from eutrophication conservation strategies, it has been certified that permanent effects of restoration can only be achieved if external nutrient loading is reduced sufficiently to low levels. Millbrook (2009) explains how

'historically environmental management strategies of freshwater systems have focused on reducing phosphorus pollution. While this has minimised freshwater algae blooms, it passed a great deal of nitrogen pollution to coastal systems'. 

With eutrophication a GLOBAL concern (affecting not only freshwater ecosystems, but coastal and marine systems),  it is becoming ever more important to acknowledge reliable management strategies. With the numbers of human population sporadically rising- euthrophication continually poses a greater threat to one of the world's most vulnerable ecosystem!

Score board update: Anthropocene 5 - 3 Biodiversity 

A melting world? Indirect impacts of sea ice loss

With the last post concentrated on the direct effects of sea ice loss in the Arctic, this post will look again at tithe phenomena of sea ice, but with a particular focus on the indirect impacts of Arctic sea ice disappearance. Below is a short video which aims to portray ice minimum volume from 1979 to 2013.

Sea ice loss may influence ecological dynamics indirectly through effects on species movements and disease transmission causing species to become more vulnerable. Arctic populations isolated when an ice free season occurs in the Arctic, the declining presence of sea ice could reduce inter-island migration. With the lengthening of the ice free season, genetic isolation among populations is encouraged (Post et al. 2013). For some species, sea ice can act as a barrier to dispersal, due to the lengthening of the sea ice free season will increase population mixing, reducing genetic differentiation. This impending loss of sea ice will increase contact among closely related series for which it currently acts as a mixing barrier. Hybridisation is likely to become increasingly common. Polar bears and grizzly bears may be the result of increasing inland presence of polar bears as a result of prolonged ice free seasons (Hoflinger, 2013).  In Canada, the projected decrease in sea ice cover with Arctic warming, will increase contact between Eastern and Western Arctic species.

Image of a 'pizzly' the grizzly-polar bear hybrid. 

A second indirect impact is changes that occur in animal behaviour as a result of sea ice loss. In the Canadian Arctic, later ice seasons and increased shipping traffic due to the lengthened ice free seasons could prevent migration of the Dolphin and Caribou (Poole et al. 2010). It is widely understood by ecologists that migration can decrease the likelihood of parasitism. The changes in ice formation within the Arctic could change the amount of parasite loads among the Dolphin migration herds. However, sea ice loss is not always looked on negatively, with the reduction of sea ice promotion migration hence preventing disease epidemics where the sea ice provides a corridor for pathogen transmission (Post et al. 2013).

Image. Caribou migration route in the Arctic. 

Sea ice loss also effects terrestrial ecosystems including especially, land adjacent to the sea ice. Arctic warming, delayed freeze season and sea ice loss will promote permafrost warming increasing terrestrial primary productivity. There has been increases in the abundance and cover of shrubs occurring across the Arctic. 

A recent report by the Arctic council and the National Oceanic and Atmospheric administration (2013) shows evidence of a shift to a new warmer, greener state. The major findings of this report include:

1) Vegetation in the Arctic is greener with a longer growing season. 

2) Wildlife and large land mammal populations continued declining trends with Caribou having unusually low numbers. 

3) Sea ice extent in September 2013 was the sixth lowest since observations began in 1979. 

4) Northward migration into the Arctic of fish such as Atlantic Mackerel and Atlantic Cod. 

This report shows that recently there has been increased concerns over this region of sea ice loss. With the academic community trying to understand how extensive the impacts of sea ice loss are. With conditions changing for many species in the Arctic, it is important to note that sea ice decline is not itself solely responsible for many individual species decline, however it plays a role with a combination of other factors. Declining sea ice is not uniform and therefore individual species responses will remain varied (Mueter and Litzow, 2007).

As we can see from the last two posts, sea ice loss can have both negative and positive effects on the ecological diversity of the Arctic. Keep your eyes peeled for the next post which will offer some insight into a completely different area of global biodiversity, one that is extremely threatened- freshwater biodiversity.


Score Board Update.

Anthropocene 4 - 3 Biodiversity 

Biodiversity in the cryosphere

As one of Earth's major biomes, the Cryosphere (taken from the Greek 'krios' meaning cold, frost or ice) is extremely important to consider when trying to understand global biodiversity. The Cryosphere encompasses those parts of the world which are frozen including, ice sheets, glaciers, frozen rivers, lakes, sea ice, permafrost and ice shelves. Today, I am focusing on the importance of sea ice to Arctic biodiversity after being fascinated by the paper published from Post et al (2013) introduced to me by my global environmental change lecture on the 6th December. With it being published only a few months ago, I decided to read the full paper and became instantly intrigued by polar biodiversity.

Sea ice compromises unique ecosystems in, on and under the ice. This habitat is critical for many species including vertebrates, diatoms, also terrestrial productivity and aquatic diversity. With 80% of the tundra in the Arctic lying within 100km of an sea ice covered ocean, Arctic ice loss driven from amplification Arctic warming is vital for ecological dynamics in this area (Post et al. 2013). Arctic amplification is the melting of ice due to a positive feedback albedo system. Ice has a high albedo therefore reflecting sunlight keeping the poles cool. However through ice melt, more of the Arctic ocean becomes exposed and due to oceans being darker they have a much lower albedo. This means they absorb heat warming the oceans and the atmosphere. As the oceans absorb heat, they also have to release this increased heat to enable the sea ice to form for the next year. Due to this feedback, the more ice loss the longer it takes for oceans to release the heat it has absorbed and therefore sea ice formation gets delayed. This can have affects for semi-aquatic species such as polar bears which use the sea ice for reproduction ground and for resting during long migration routes.

With anthropogenic warming Arctic sea ice extent has slowly been declining.

Source. A) Graph showing the declining annual minimum Arctic sea ice extent from 1979 to 2012. Although,  there is seasonal variability the overarching trend is a decline. B/C) Two maps showing the percentage concentration loss of sea ice with the scale bar showing -5% to 5% change. B is from 1979-1999 and C from 2000 -2011. 


The trend seen in the maps is showing percentage loss, especially around the edges of the sea ice, due to warming oceans.

The direct effects of Arctic sea ice loss

1. Primary producers depend on the sea ice habitat, underpinning the whole Arctic marine food web.

- With the loss of sea ice, this is a loss of habitat for algae and phytoplankton.  The timing of the algae bloom which is ultimately driven by light penetrating the ice when it is thin enough, is vital for the reproduction of zooplankton grazers. Disruption of this timing due to accelerated ice melt has created mismatches for zooplankton production timing and the consumers up the food chain.
- Earlier phytoplankton blooms can shorten the length for primary productivity consequently affecting the zooplankton production and the Arctic cod species that feed on them (Post et al. 2013).

2. With ice melt comes increasing freshness of the Arctic ocean.
- This reduces the nutrient availability for phytoplankton which limits their productivity despite increased solar penetration through ice thinning.

3. As previously touched upon, vertebrate species such as polar bears require sea ice for reproduction and resting and therefore they are directly implicated by sea ice thinning. One species also effected is the ringed seal (Gohring, 2012). More than two thirds of the Arctic has been estimated to have insufficient snow cover for ringed seals to reproduce challenging their whole survival. A ringed seal is currently under consideration for the threatened species list due to the way it builds caves to rear its offspring in snow drifts on sea ice (NOAA, 2013).  (Hezel et al. 2012) estimated that snow drifts must be at least 20cm deep to support the caves. As sea ice disappears, there is no where for the snow to pile up, ultimately declining the area where the seals can reproduce. What is also worrying is that with earlier snow melt year on year, the caves will melt also much earlier, leaving the young vulnerable to the outside conditions and predators.

Next week, I will be continuing the polar theme by exploring the indirect impacts of sea ice loss in the Arctic so keep those eyes peeled. Only two weeks till christmas!!

Score Board Update: Anthropocene 4 - 2 Biodiversity. 

Discovery of new species everyday: Is biodiversity increasing?

Moving away from the ocean focus from the past two weeks, todays post explores a recent article by the BBC about the identification of a new wild cat in Brazil by Coles (2013).

Everyday I look on Nature and there is an article about a new species being discovered. These new species are found in a range of locations from Burma to closer to home in the United Kingdom. With new species being discovered everyday, is it possible to make the judgement that biodiversity is possibly increasing on local scales around the world?

Check out the Coles (2013) article and make up your own judgements. It is important to note that we do not know everything about the natural world and therefore to make all encompassing conclusions about global biodiversity, is extremely difficult.  These conclusions are strictly based on the knowledge we do have while accepting the unknown.

Articles to check out:

New species of Hammerhead shark discovered off Carolina coast (Kenniff, 2013)

Spectacular New Species Found in the Lost World (Dell'Amore, 2013).

New Species of 'Skeleton Shrimp' discovered (Vincent, 2013).

Score Board Update: Anthropocene 3 - 2 Biodiversity