Tag Archives: biodiversity

They only care if you are cute: how charisma harms biodiversity

by Piter Kehoma Boll

Which of the two species shown below is more charismatic?

Tangara_chilensis

Tangara chilensis (Paradise Tanager). Photo by flickr user ucumari.*

854px-apocrypta_guineensis2c_volw-wyfie_op_f_sur2c_manie_vd_schijff_bt2c_f

Apocrypta guineensis (a fig wasp). Photo by Wikimedia user JMK.**

You probably would pick the first one. And if I’d ask you which one deserves more attention and efforts to be preserved, you would likely choose the bird as well, or at least most people would. But what is the problem with that? That’s what I am going to show you now.

As we all know, the protection of biological diversity is an important subject in the current world. Fortunately, there is an increase in campaigns promoting the preservation of biodiversity, but unfortunately they are almost always directed to a small subset of species. You may find organizations seeking to protect sea turtles, tigers, eagles or giant pandas, but can you think of anyone wanting to protect beetles? Most preservation programs target large and charismatic creatures, such as mammals, birds and flowering plants, while smaller and not-so-cute organisms remain neglected. And this is not only true in environments that included non-biologist people, but in all fields of research. And more than only leading to a bias in the protection of ecosystems, this preference leads to thousands of understudied species that could bring biotechnological revolutions to humandkind.

In an interesting study published this week in Nature’s Scientific Reports (see reference below), Troudet et al. analyzed the taxonomic bias in biodiversity data by comparing the occurrence of data on several taxonomic groups to those groups’ diversity. The conclusions are astonishing, although not that much surprising. The most charismatic groups, such as birds, are, one could say, overstudied, with an excess of records, while other, such as insects, are highly understudied. While birds have about 200 million occurences above the ideal record, insects have about 200 million below the ideal number. And the situation does not seem to have improved very much along the years.

41598_2017_9084_fig1_html

The bias in interest is clear. The vertical line indicates the “ideal” number of occurrences of each group. A green bar indicates an excess of occurrences, while a red bar indicates a lack of occurrences. Birds and Insects are on the opposite extremes, but certainly the insect bias is much worse. Figure extracted from Troudet et al. (2017).***

Aditionally, the study concluded that the main reason for such disparity is simply societal preference, i.e., the most studied groups are the most loved ones by people in general. The issue is really a simple matter of charisma and has little to do with scientific or viability reasons.

The only way to change this scenario is if we find a way to raise awareness and interest of the general public on the less charismatic groups. We must make them interesting to the lay audience in order to receive their support and increase the number of future biologists that will choose to work with these neglected but very important creatures.

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See also:

Once found and then forgotten: the not so bright side of taxonomy

The lack of taxonomists and its consequences on ecology

Unknown whereabouts: the lack of biogeographic references of species

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Reference:

Troudet, J.; Grandcolas, P.; Blin, A,; Vignes-Lebbe, R.; Legendre, F. (2017) Taxonomic bias in biodiversity data and societal preferences. Scientific Report 7: 9132. https://dx.doi.org/10.1038/s41598-017-09084-6

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Old Italian trees: a step toward worldwide recognition?

by Piter Kehoma Boll

Some years ago I wrote an article (you can read it here) about the importance of trees, especially old trees, and how their ecological role is different from that of a young tree.

old_tree

Ancient trees are ecological preciosities and need to be preserved for the sake of their ecosystems. Photo by flickr user loshak.*

In Italy, there are specific laws erected to protect ancient trees, especially if they are unique for their species or have some sort of aesthetic or cultural value. Recently, their importance for the preservation of a variety of lifeforms has also started to be recognized. A recently published article by a group of Italian researchers (see below) compared the noteworthy old trees in Italy recorded in a previous list and a new list. They conclude that the new inventory has considerable improvements, although some issues remain, including the presence of exotic, even invasive, species in the list.

But such initiatives are at least important as a first step that may guide us to a better understanding and management of old trees, which are precious elements, but continue to decline worldwide.

Read the study for free:

Zapponi, L.; Mazza, G.; Farina, A.; Fedrigoli, L.; Mazzocchi, F.; Roversi, P. F.; Peverieri, G. S.; Mason, F. (2017) The role of monumental trees for the preservation of saproxylic biodiversity: re-thinking their management in cultural landscapes. Nature Conservation 19: 231–243.

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Friday Fellow: Hummingbird Bobtail Squid

by Piter Kehoma Boll

If you are digging through the sand at the bottom of the clear tropical waters around Indonesia and the Philippines, you may end up finding a colorful little creature, the hummingbird bobtail squid, Euprymna berryi, also known as Berry’s bobtail squid.

Euprymna_berryi

A beautiful specimen photographed in East Timor. Photo by Nick Hobgood.*

Measuring about 3 cm if male or 5 cm if female, the humminbird bobtail squid is actually more closely related to cuttlefish than to true squids. Its body has a translucent skin marked by many black chromatophores, and to the human eye the animal seems to have a color pattern formed by a blend of black, electric blue and green or purple dots.

During the day, the hummingbid bobtail squid remains most of the time buried in the sand, coming out at night to capture small crustaceans, which it hunts using a bioluminescent organ in its gill cavity.

In some areas around its distribution, the hummingbid bobtail squid is captured and sold in small fisheries, but as the data on the distribution and population dynamics of this species are very poorly known, there is no way to say whether it is vulnerable or endangered in any way. As a result, it is listed as Data Deficient in the IUCN Red List.

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ResearchBlogging.orgReferences:

Barratt, I., & Allcock, L. (2012). Euprymna berryi The IUCN Red List of Threatened Species DOI: 10.2305/IUCN.UK.2012-1.RLTS.T162599A925343.en

Wikipedia. Euprymna berryi. Available at <https://en.wikipedia.org/wiki/Euprymna_berryi&gt;. Access on March 8, 2017.

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The warmer the dangerouser, at least if you are a caterpillar

by Piter Kehoma Boll

Scientist all over the world agree that species diversity is higher at the tropics than at polar regions, i.e., the closer you get to the equator, more species you will find. But apart from making food webs more entangled, does it increase the overall number of interactions that species experience? Afterall, despite the increase in species richness, the population size usually decreases. For example, while there are hundreds of different tree species in the Amazon forest, the number of individuals of each species is much lower than the number of individuals of a species in a temperate forest in Europe.

In order to test whether an increase in species richness would also mean an increase in biotic interactions, a group of ecologists all over the world engaged in a worldwide experiment using nothing else but small fake caterpillars made of plasticine. The small models were placed in different areas from the polar regions to the equatorial regions and the number of attacks that they suffered were counted and grouped according to the type of predator, which was usually identifiable based on the marks left on the models.

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A fake caterpillar in Tai Po Kau, Hong Kong. Photo by Chung Yun Tak, extracted from ScienceDaily.

The results indicate that there is indeed an increase in predation rates towards the equator, as well as towards the sea level. Areas close to the poles or at high elevations have a smaller number of interactions. But even more interesting was the revelation that this change is really driven by small predators, especially arthropods such as ants. The rate of attacks by birds and mammals was fairly constant across the globe.

Such an evidence on the importance of arthropod predators at the tropics may make us reevaluate our ideas on the evolution of species in such places, as the main concern for small herbivores such as caterpillars in tropical forests may not be birds, but ants. And this means a completely different way to evolve defense strategies.

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ResearchBlogging.orgReference:

Roslin, T., Hardwick, B., Novotny, V., Petry, W., Andrew, N., Asmus, A., Barrio, I., Basset, Y., Boesing, A., Bonebrake, T., Cameron, E., Dáttilo, W., Donoso, D., Drozd, P., Gray, C., Hik, D., Hill, S., Hopkins, T., Huang, S., Koane, B., Laird-Hopkins, B., Laukkanen, L., Lewis, O., Milne, S., Mwesige, I., Nakamura, A., Nell, C., Nichols, E., Prokurat, A., Sam, K., Schmidt, N., Slade, A., Slade, V., Suchanková, A., Teder, T., van Nouhuys, S., Vandvik, V., Weissflog, A., Zhukovich, V., & Slade, E. (2017). Higher predation risk for insect prey at low latitudes and elevations Science, 356 (6339), 742-744 DOI: 10.1126/science.aaj1631

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Land snails on islands: fascinating diversity, worrying vulnerability

by Piter Kehoma Boll

The class Gastropoda, which includes snails and slugs, is only beaten by the insects in number of species worldwide, having currently about 80 thousand described species. Among those, about 24 thousand live on land, where they are a very successful group, especially on oceanic islands.

The Hawaiian Islands alone, for example, have more than 750 snail species and there are more than 100 endemic species in the small island of Rapa in the South Pacific. This diversity is much higher than that in any continental place, but the reason for that is not completely understood.

Mandarina

A land snail of the genus Mandarina, endemic to the Ogasawara Islands, Japan. Photo by flickr user kmkmks (Kumiko).*

One of the most likely explanations for this huge diversity on islands is related to the lack of predators. The most common predators of snails include birds, mammals, snakes, beetles, flatworms and other snails. Most of those are not present in small and isolated islands, which allows an increase in land snail populations in such places. Without too much dangers to worry about, the community of land snails n islands can explore a greater range of niches, eventually leading to speciation.

Unfortunately, as always, the lack of danger leads to recklessness. Without predators to worry about, insular land snails tend to lay fewer eggs than their mainland relatives. If there is no danger of having most of your children eaten, why would you have that many? It is better to lay larger eggs, putting more resources on fewer babies, and so assure that they will be strong enough to fight against other snail species. Afterall, the large number of species in such a small place as an island likely leads to an increased amount of competition between species.

But why is this recklessness? Well, because you never known when a predator will arrive. And they already arrived… due to our fault.

The diversity of insular land nails was certainly affected by habitat loss promoted by humans, but also by predators that we carried with us to the islands, whether intentionally or not. These predators include rats, the predatory snail Euglandina rosea and the land flatworm Platydemus manokwari, the latter being most likely the worst of all.

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The flatworm Platydemus manokwari in the Ogasawara Islands. Photo by Shinji Sugiura.

This flatworm arrived at the Chichijima Island, part of the Ogasawara Islands in the Pacific Ocean, in the early 1990s and in about two decades it led most land snail species on the island to extinction and many more are about to face the same fate on this island and on others. Not being prepared for predators, these poor snails cannot reproduce fast enough to replace all individuals eaten by the flatworm.

We have to act quickly if we want to save those that are still left.

See also: The New Guinea flatworm visits France – a menace.

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ResearchBlogging.orgReferences and further reading:

Chiba, S., & Cowie, R. (2016). Evolution and Extinction of Land Snails on Oceanic Islands. Annual Review of Ecology, Evolution, and Systematics, 47 (1), 123-141 DOI: 10.1146/annurev-ecolsys-112414-054331

Sugiura, S., Okochi, I., & Tamada, H. (2006). High Predation Pressure by an Introduced Flatworm on Land Snails on the Oceanic Ogasawara Islands. Biotropica, 38 (5), 700-703 DOI: 10.1111/j.1744-7429.2006.00196.x

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Friday Fellow: Tree Tumbo

by Piter Kehoma Boll

Today I’m introducing one of the most bizarre plant species in the world. Found in the Namib desert, in Namibia and Angola, the Welwitschia mirabilis, usually simply called welwitschia or tree tumbo in English, is the solely member of the order Welwitschiales, a group of gymnosperms in the division Gnetophyta.

welwitschia_mirabilis

A specimen of Welwitschia mirabilis in Naukluft, Namibia. Photo by Sara&Joachim*

The tree tumbo has a unique appearance. The seedlings have two cotyledons (the original leaves produced by the seed) and later develop two permanent leaves that grow opposite (at right angles) to the cotyledons. These permanent leaves grow continuosly, reaching up to 4 m in length. While growing, the leaves split and fray into several straps and occupy an area of about 8 m in circunference around the plant. The stem is woody and the flowers appear on a central part called crown. The species is dioecious, meaning that male and female flowers appear in different plants. Pollination is usually carried out by insects.

Living up to 2 thousand years, the tree tumbo is a very peculiar desert plant. Its leaves are broad and very large, different from what is the rule in the desert. Its root system is also very shallow, not penetrating deep in the ground. It seems that most of the water used by the plant is captured by the leaves from the morning fog.

Although having a very restrict range, the tree tumbo is not (yet) and endangered plant, as its population is considerably large. However, due to its popularity, some areas attract collectors, and since its growth is so slow, it may eventually become a vulnerable plant.

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References:

Bornmann, C. H. 1972. Welwitschia mirabilis: paradox of the Namib Desert. Edeavour, 31(113):95–99.

Wikipedia. Welwitschia mirabilis. Available at <https://en.wikipedia.org/wiki/Welwitschia&gt;. Access on March 1, 2017.

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Friday Fellow: Paraná pine

by Piter Kehoma Boll

As the first conifer Friday Fellow, I decided to choose one of my beloved ones, the Paraná pine, Araucaria angustifolia, also known as Brazilian pine or candelabra tree.

The Paraná pine can reach up to 50 m in height, although most trees are smaller than that. They have a very particular shape and are easily distinguished from the surrounding forest where they occur, the so-called Mixed Ombrophilous Forest or Araucaria Moist Forest, in southern Brazil. The trees have a cylindrical trunk with a dark and thin bark that detaches in large and flexible pieces, being gray on the outer surface and reddish on the inner one. The crown changes its appearance during the development, being conical in young trees and with a candelabrum-like shape in mature specimens. Mature trees usually stand with their crowns above the forest canopy, which gives the Araucaria moist forest its particular look. The leaves grow in a spiral pattern around the stem and are very hard with a sharp point that can easily pierce through the human skin.

araucaria_angustifolia

A group of Paraná pines in Campos de Jordão, Brazil, close to the northernmost distribution of the species. Photo by Vinícius Ribeiro.*

The species current distribution is almost restricted to Brazil, from northern Rio Grande do Sul to southern São Paulo, with some small populations occurring in neighboring areas of Argentina and Paraguay. Once an abundant species, its population has been drastically reduced due to the heavy logging until the middle of the 20th century and the exploitation for the use of its seeds, called pinhão in Portuguese. As a result, it is currently considered as Critically Endangered by IUCN.

araucaria_angustifolia2

An adult tree in the municipality of Colombo, Paraná, Brazil. Photo by Mauro Guanandi.*

The paraná pine is a dioecious species, i.e., males and females are separate plants. As most conifers, it is pollinated by the wind. The large cones, which take two years to become ripe, contain a number of large and edible seeds used as food by many animals, as well as by humans. Pinhões cooked in salty water is a typical dish in southern Brazil during winter. One of the main seed dispersers of the Paraná pine is the azure jay, Cyanocorax caeruleus, which buries the seeds for future use.

araucaria_angustifolia3

A cone and lose seeds of Araucaria angustifolia in a market. Photo by Marcelo Träsel.**

As most (if not all) conifers, the Paraná pine forms mutualist associations with fungi, such as the glomeromycete Glomus clarum. Thus, in order to preserve this amazing tree, it is also necessary to guarantee the preservation of all its partner species, such as mycorrhizal fungi and seed dispersers.

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ResearchBlogging.orgReferences:

Angeli, A. (2003). Araucaria angustifolia (Araucaria). Departamento de Ciências Florestais – ESALQ/USP. Available at: <http://www.ipef.br/identificacao/araucaria.angustifolia.asp&gt;. Access on January 26, 2017.

IUCN (2016). Araucaria angustifolia The IUCN Red List of Threatened Species DOI: 10.2305/IUCN.UK.2013-1.RLTS.T32975A2829141.en

Soares, T. S. (2004). Araucária – o pinheiro brasileiro. Revista Científica Eletrônica de Engenharia Florestal, 2 (3).

SOUZA, A. (2007). Ecological interpretation of multiple population size structures in trees: The case of Araucaria angustifolia in South America Austral Ecology, 32 (5), 524-533 DOI: 10.1111/j.1442-9993.2007.01724.x

Zandavalli, R., Dillenburg, L., & de Souza, P. (2004). Growth responses of Araucaria angustifolia (Araucariaceae) to inoculation with the mycorrhizal fungus Glomus clarum. Applied Soil Ecology, 25 (3), 245-255 DOI: 10.1016/j.apsoil.2003.09.009

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