Closing a knowledge gap: islands, unique species, and conservation

by Dena Spatz

So many islands, with such limited capacity: what information informs prioritization?

Re-posted from the Coastal Sustainability blog:   Stories Of Sustainability Research And Engagement From The Students And Scholars At UC Santa Cruz

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Islands come in many different shapes and sizes, but what many have in common is that they are home to unique and threatened species.

Scientists play a critical role in helping to decide which species are protected or what habitats to restore. They inform conservation decision making by providing information on where a species may live, what they do, or how they function in their native habitat. While conservation projects are a combination of scientific, technological, political, and social threads, woven together to produce a certain course of action, in some cases we simply lack the scientific foundation to make decisions about where to work or what to protect. For example, sometimes we don’t even know where a species of concern lives, and this is a basic knowledge gap that should filled so science can effectively guide conservation decisions.

​This is often the case on islands. Islands are sometimes the tropical paradise one would think of when hearing the word, but are more often desolate volcanic rocks, or eroded landmasses, shaped and sculpted by winds and time, and isolated by water and distance from the continents where most of us live. The species found on islands are as unique as the island itself; often found nowhere else in the world. Due to the small sizes and inherent isolation of islands, island species have evolved with few neighbors and visitors. Thus, island species have adapted to low levels of competition and predation and lack defensive strategies that are common in species found on continents with lots of predators.  These conditions make islands unique, yet also leave its inhabitants vulnerable.  For example, the Dodo was a flightless island pigeon famous for a lack of aggression and defenseless behavior. Dodos never resisted a hunter’s gun, nor an attack by the cats or rats that came along on the hunter’s boats, and they quickly became extinct at the hand of such disturbances.  ​

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Island species that have gone extinct since the colonization of islands by people shown only by museum specimens and illustration, contrasted by the introduced species that settlers and explores have brought to islands.

Critically Endangered and Endangered island species. From top left to right: Temotu flying fox by (by R. Pierce), Lesser Antillean Common Iguana (by G. Moulard), Balearic shearwater (by D. Oro), Desecheo Anole (by Island Conservation), Flame-templed Babbler (by A. Pascua), Giant Busy-tailed Cloud Rat (by D.S. Balete).

Since people began colonizing the world, over 60% of extinctions, including 95% percent of all bird and 53% of all mammal extinctions, have occurred on islands. Today, 37% of all Critically Endangered species are living on only 5% of our planet’s land area; on islands. Hunting and poaching, habitat conversion, and intense predation from introduced species from the mainland (like the Eurasian cats and rats in the Dodo story) are the primary causes for loss of these species. Changes in climate and increased sea levels will likely have a compounding impact in the future.  
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To tackle this problem, I am identifying key information about threatened island species. For instance, the Temotu flying fox (a bat from the Soloman Islands), the Flame-templed Babbler (a bird from the Philippines), and the Lesser Antillean Green Iguana from the Caribbean show cause for concern, yet we do not have comprehensive information about the basic traits of these species. I ask questions about where the species was last seen, if its natural range has declined and where it used to occur, and what is known to be driving the extinction process. To do this, I’ve sifted through over 1000 documents, including the notes of 16th century explorers and early natural historians, and interviewed 100s of island users – from visiting scientists, to locals, to tourism groups. The results reveal the incredible stories of islands, the journeys of people who’ve worked tirelessly to study them, and the scope and severity of threats that island systems are experiencing. My research is an effort to compile data on more than 1200 threatened island species on over 1400 islands worldwide, fulfilling a knowledge gap needed to direct successful conservation on vulnerable island systems.

For more information about islands,  threats to island species, and conservation decision making, check out these references:

• DIISE (2015). The Database of Island Invasive Species Eradications, developed by Island Conservation, Coastal Conservation Action Laboratory UCSC, IUCN SSC Invasive Species Specialist Group, University of Auckland and Landcare Research New Zealand. http://diise.islandconservation.org.
• Gregory, R., Failing, L., Harstone, M., Long, G., McDaniels, T., & Ohlson, D. (2012). Structured decision making: a practical guide to environmental management choices. John Wiley & Sons.
• IUCN Red List of Threatened Species (2014)
• Tershy, B. R., Shen, K. W., Newton, K. M., Holmes, N. D., & Croll, D. A. (2015). The importance of islands for the protection of biological and linguistic diversity. BioScience, 65(6), 592-597.
• Threatened Island Biodiversity Database Partners (2014). The Threatened Island Biodiversity Database: developed by Island Conservation, University of California Santa Cruz Coastal Conservation Action Lab, BirdLife International and IUCN Invasive Species Specialist Group. Version 2014.1 www.tib.islandconservation.org
• Veitch, C. R., & Clout, M. N. (2002). Turning the tide: The eradication of invasive species: Proceedings of the International Conference on Eradication of Island Invasives (No. 27). IUCN.

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