Bird Enthusiasts & Coffee Aficionados, Unite!

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Do you like fancy coffee? Birds do too, but not for the morning pick-me-up that millions of people rely on every day.

Agroforestry, the practice of growing crops alongside larger native trees and shrubs in a heterogeneous landscape, can provide a host of benefits to farmers and the environment, from increased crop productivity and soil fertility to protection against erosion, winds, and flooding. In Costa Rica, where coffee is often grown in agroforests, there may be yet another advantage to this kind of land use: birds have taken a liking to these shade-grown coffee plantations.

In the past, global conservation efforts were largely focused on setting aside as much pristine land as possible, but increasingly, the effort to protect the environment includes recommending steps we can take to use land in a more eco-friendly way. Given the habitat loss from shrinking forests in Costa Rica, researchers from the University of Georgia asked how well shade-grown coffee plantations could function as a “surrogate habitat” for birds. Past research has found a high degree of biodiversity in Costa Rica’s coffee agroforests, but much of it was limited in scope or focused on individual species. This latest research, published in PLOS ONE, provides a detailed analysis of avian populations in these coffee agroforests.

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In this study, scientists hung mist nets in both undeveloped forest patches and in coffee agroforests, to capture and count nearly one hundred different bird species in the Monteverde region of Costa Rica, a major ecotourism hotspot (arial photo of collection site below). Using models that accounted for seasonal differences in the two habitats, capture rates for different bird species, and bird community behaviors, the researchers described three different bird communities–insectivores, omnivores, and frugivores (fruit eaters)–in secondary forest habitats and in shade-grown coffee agroforests.  In particular, the analysis showed that the bird community composition and dynamics in shade-grown coffee plantations embedded in the tropical landscape are very similar (although not identical) to those found in secondary forests, a finding which supports the hypothesis that coffee agroforests can be a suitable surrogate habitat for birds.

Figure 1

The authors also suggest that the coffee agroforests may serve as wildlife corridors for birds, allowing them to move freely between larger patches of forest within a fragmented landscape. This kind of habitat linkage is critical, as connecting wild spaces via such corridors maximizes the ecological benefits they provide. The authors do caution that providing managed habitat for birds in the form of shade-grown coffee should be viewed as a complementary rather than a contradictory strategy for protecting bird habitat, as nothing can substitute for the preservation of forest habitat. But in a region where ecotourism and birdwatchers are primary economic drivers (the Three-wattled Bellbird and Resplendent Quetzal are two prominent locals), this knowledge could help inform the land management decisions that are so crucial to birds and humans alike.

Related Posts:

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Citation: Hernandez SM, Mattsson BJ, Peters VE, Cooper RJ, Carroll CR (2013) Coffee Agroforests Remain Beneficial for Neotropical Bird Community Conservation across Seasons. PLoS ONE 8(9): e65101. doi:10.1371/journal.pone.0065101

Image 1: Coffee agroforest in Costa Rica from Wikipedia

Image 2: Image of a Resplendent Quetzal on Flickr by Frank Vassen

Image 3: Figure 1 of the manuscript

Heating up the Science Behind PLOS’ New Climate Change Collection

Satellite images of penguin colonies in the southern Ross Sea

From penguin colonies in Antarctica, to California birds and North Carolina bugs, this month PLOS ONE focuses on the far-reaching aspects of climate change. In conjunction with the annual meeting of the Ecological Society of America (ESA), PLOS ONE and PLOS Biology unrolled a new collection of 16 research articles, curated by PLOS ONE Academic Editor, Ben Bond-Lamberty. The collection, “Ecological Impact of Climate Change”, features many articles that made a splash in the media. Here are some of the highlights:

Spring flowers are blooming earlier now than they did in the past. In a recent study, researchers compared the average flowering time for native species in Massachusetts and Wisconsin to data recorded by notable American naturalists Henry David Thoreau and Aldo Leopold. These native species have shown remarkable flowering shifts, especially during recent years: In 1865, Thoreau observed the highbush blueberry flowering in mid-May; in 2012, researchers observed this species flowering six weeks earlier in early April. For more about this study, visit National Geographic, NPR, and MSNBC.

Like spring flowers, corals also react to increasing temperatures, but to a much more ghostly effect. When pressured by unusually warm or polluted waters, corals shed the algae that enliven them with color, becoming white.

Tioman Island, Malaysia, Acropora colony

New research suggests that this phenomenon, known as coral bleaching and often fatal for coral colonies, may not be as devastating as expected: Coral colonies that survived previous coral bleaching were much more likely to rebound successfully the next time it occurred. An astounding 95% of Acropora, a coral species highly susceptible to bleaching, survived at a research site in Singapore in 2010. Read more about these tough coral taxa, in the New York Times blog.

Summer days are heating up in the city, too, and urban, tree-dwelling insects are thriving as a result. A recent PLOS ONE article reports that scale insects like Parthenolecanium quercifex are 13 times more numerous in the hottest parts of Raleigh, North Carolina, than in cooler, neighboring rural areas.

Scale Bugs CCBY Aug blog

And these scaly squatters don’t stop once they settle down. Researchers also found that urban scale insects were four times more abundant when placed in hot greenhouse conditions than rural scale insects in the same conditions. The Atlantic Cities and Discovery News have more on this and other urban insects studies.

As temperatures continue to rise, researchers in this PLOS ONE study integrated climate change threats with traditional conservation concerns by comparing the vulnerability of California’s birds in relation to the predicted effects of climate change over the coming years. Of the 29 threatened-bird taxa considered in the state of California, these researchers determined 21 of those 29 (72%) are considered vulnerable to climate change. Lucky for us and the birds who call those most vulnerable coastal environments home, the findings of this study can be used as an assessment tool to foster future conservation efforts. For more local and international coverage, check out KQED News and the Huffington Post.

Read Ben Bond-Lamberty’s overview of the Collection, learn how climate change may impact coffee plants, or more from the PLOS Blogs network. View the entire Collection here. For more news on PLOS ONE papers headlining in August, dive into our Media Tracking Project.

Citations:

Ellwood ER, Temple SA, Primack RB, Bradley NL, Davis CC (2013) Record-Breaking Early Flowering in the Eastern United States. PLoS ONE 8(1): e53788. doi:10.1371/journal.pone.0053788

Guest JR, Baird AH, Maynard JA, Muttaqin E, Edwards AJ, et al. (2012) Contrasting Patterns of Coral Bleaching Susceptibility in 2010 Suggest an Adaptive Response to Thermal Stress. PLoS ONE 7(3): e33353. doi:10.1371/journal.pone.0033353

Meineke EK, Dunn RR, Sexton JO, Frank SD (2013) Urban Warming Drives Insect Pest Abundance on Street Trees. PLoS ONE 8(3): e59687. doi:10.1371/journal.pone.0059687

Gardali T, Seavy NE, DiGaudio RT, Comrack LA (2012) A Climate Change Vulnerability Assessment of California’s At-Risk Birds. PLoS ONE 7(3): e29507. doi:10.1371/journal.pone.0029507

Image 1: Satellite images of penguin colonies in the southern Ross Sea. doi:10.1371/journal.pone.0060568

Image 2: Tioman Island, Malaysia, Acropora colony. doi:10.1371/journal.pone.0033353

Image 3: Ants and sapsuckers by John Tann

 

Prowling Catfish Catch Pigeons on Land

Cats hunt birds, and sea-birds hunt fish.  And in some odd ecological pockets, catfish hunt pigeons.

In a study published today by researchers at the University of Toulouse, France, scientists have investigated this unusual predator-prey relationship between European catfish and pigeons in the Southwest region of France.

European catfish have been reported to capture the pigeons on land and drag them back into the water.  This surprising behavior has not been known to occur in the native range of the species; however this article discovers that in France, where the fish are an invasive species, they have adapted their natural behavior in order to feed on novel prey in their new environment.

The researchers completed this study along the Tarn River in Southwestern France.  European catfish originate from Europe, east of the Rhine River, but were introduced to the Tarn River in 1983.

From a bridge above a gravel island on the river, the researchers watched the fish from June through October 2011. Over that time they saw 54 pigeon hunting incidents, and in 28% of these cases, the catfish successfully captured their prey on land and dragged them back into the water to eat them. These attacks were nearly always triggered by active pigeons, as catfish never attacked motionless pigeons. This evidence suggests that the catfish used water vibrations to hunt their prey rather than visual cues.

The cause of this unusual predation behavior is still unknown. However, these new findings may bring us closer to understanding the implications of such novel behavior in a new ecosystem.

To view the fascinating catfish behavior described in this article, please see the video below:

Citation: Cucherousset J, Boulêtreau S, Azémar F, Compin A, Guillaume M, et al. (2012) “Freshwater Killer Whales”: Beaching Behavior of an Alien Fish to Hunt Land Birds. PLoS ONE 7(12): e50840. doi:10.1371/journal.pone.0050840

Spiders, Birds, and Snakes, Oh my!

To continue our spooktacular posts this October, we bring you a study which may have some arachnophobes rethinking their next vacation destination.

The island of Guam is home to one of the densest spider communities in the Pacific.  In a recent study published with PLOS ONE, researchers investigated this region to discover how the demise of insectivorous birds inhabiting the island has affected one of the most widely feared creepy crawlers.

The downfall of Guam’s native insect-eating birds began in the 1940’s when the infamous brown tree snake was introduced.  To investigate the effects this loss had on the landscape, the authors of the recent paper analyzed the spider population on several Pacific islands.

The team compared the neighboring islands of Rota, Tinian and Saipan, to Guam. These islands do not have any known snake populations, and also have similar native bird species to that of Guam.  The researchers were then able to assess whether the bird presence correlated with spider web numbers, in addition to what impact bird presence had per season.

What the authors found might send chills right down your spine: The spider web densities in Guam were 40 times higher than those of the other islands during the wet season. Guam had an average of 18.37 spider webs per 10 meters, as compared to the other islands, which only had 0.45 webs per 10 meters. In addition, the bird loss had even increased the web size for a certain spider species.

Whether you suffer from arachnophobia, ophidiophobia (fear of snakes) or ornithophobia (fear of birds), I think we can all agree this is a terrifying case showing the effects the removal of an essential predator can have to a landscape.

Citation: Rogers H, Hille Ris Lambers J, Miller R, Tewksbury JJ (2012) ‘Natural experiment’ Demonstrates Top-Down Control of Spiders by Birds on a Landscape Level. PLoS ONE 7(9): e43446. doi:10.1371/journal.pone.0043446

Image Credit: Anders B on Flickr CC-by license