Dispatches

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Wild bees boost CA crops

Robin Meadows

A new study shows that wild bees do far more for California agriculture than expected, pollinating up to 40% of pollinator-dependent crops and thus providing up to $2.4 billion in ecosystem services. “We were surprised by how much native bees can provide”, says lead author Rebecca Chaplin-Kramer of the University of California, Berkeley. “It's much higher than other estimates.” Earlier work had put US crop pollination services from wild bees at only 15%.

Why the difference? The previous estimate assumed a fixed ratio of wild bees to European honeybees (Apis mellifera), rather than accounting for the fact that wild bee numbers vary greatly among habitat types. “There was a huge piece missing”, Chaplin-Kramer points out. “Where were pollinators coming from and were we really getting services?” In contrast, she and her colleagues mapped the types of wild-land habitats near farmlands. The researchers identified wild-bee-rich habitats based partly on their flowering plants, which supply nectar for bees. They had previously shown that the proportion of natural habitat around farms determines the pollination services from wild bees, and used this relationship to calculate these services statewide in their study, which appeared in the June issue of Rangelands (doi:10.2111/1551-501X-33.3.33).

Figure 1.

Osmia ribifloris, a bee native to California.

“Mapping can identify hotspots of natural habitat that will benefit farmers the most”, Chaplin-Kramer continues. Worldwide, about 75% of crop types depend on pollinators to some degree; melons and squash, for example, require pollinators, while crop yields of almonds, stone fruits, and most berries are enhanced by pollinators.

The researchers' close look at the wildlands around farms also revealed that most wild bee pollination services in California come from rangelands. “This was the other big surprise”, Chaplin-Kramer says. “Farmers are benefitting from rangelands and not just pristine ecosystems.” Rangelands include grasslands, meadows, savannas, and shrublands, and this diversity of habitats fosters a diversity of wild bees. Rangelands provide bees with nectar sources that bloom successively from spring through fall, as well as nest sites, including holes in the ground, hollow-stemmed grasses, and tree cavities.

These findings suggest that boosting rangeland conservation – and thus wild bee populations – could help to counteract the decline of the European honeybees, which many California farmers currently depend on for pollination. “It's good insurance to have wild bees in case the honeybees crash”, remarks Chaplin-Kramer.

Getting to the heart of wildfires and human health

Jane Bradbury

Exposure to smoke from peat-bog wildfires may increase the risk of cardiovascular problems in nearby residents, suggests a new study. Wayne Cascio of the US Environmental Protection Agency (Research Triangle Park, NC) and colleagues report that emergency room visits for symptoms associated with heart failure rose significantly among people exposed to smoke from a peat wildfire that occurred in June 2008 in eastern North Carolina. “As in previous studies, exposure to wildfire smoke increased emergency room visits for respiratory problems”, notes Cascio, “but the increase we saw in hospital visits for heart failure was surprising”. Cascio speculates that differences in the chemistry of the smoke produced by peat and forest wildfires could underlie this unexpected result.

Given that climate change might alter wildfire patterns by increasing temperatures in boreal regions and changing precipitation patterns elsewhere, understanding the effects that wildfire smoke exposure has on human health is increasingly important, says geographer Tatiana Loboda (University of Maryland, College Park, MD), who is studying the impact of wildfire emissions on human health under climate-change scenarios. “When we consider the combined effects of changing weather patterns, fuel buildup after years of fire suppression within the US, and the climate-induced increase in insect-pest-driven mortality of forests in North America, there's a good chance that the impact of fire, at least on respiratory health, will become a more prominent issue”, she continues.

Cascio and his colleagues used satellite-based imagery to identify counties in eastern North Carolina affected by smoke from the 2008 wildfire event. They analyzed data on emergency room visits recorded for people complaining of cardiac and respiratory ailments in exposed and neighboring unexposed counties during and shortly after high exposure days versus those during the following 6 weeks. In the exposed counties, there was a 37% increase in hospital visits for symptoms of heart failure during and immediately after the period of high levels of high smoke exposure (Environ Health Persp 2011; doi:10.1289/ehp.1003206).

Comments Loboda, “This research adds to the data about the impacts of wildfire emissions on human health and, importantly, provides more definitive evidence for a link between cardiopulmonary conditions and wildfire emissions than previously seen”.

Washington's Elwha River to run free

Noreen Parks

In early June, generators at a 1913 power plant on the Elwha River – a 45-mile-long river in Washington State's Olympic Peninsula – fell silent, setting the stage for the largest dam removal project in US history. Elimination of two dams will allow the river to once again flow freely through the old-growth forests of Olympic National Park and down to the Strait of Juan de Fuca, re-opening more than 70 miles of stream habitat for salmon and other anadromous fish. Prior to construction of the dams in the early 1900s, the Elwha fishery was the stuff of legend – reaching upwards of 300 000 salmon annually – but by 2005, catches had plummeted to less than 1% of that bounty.

While the impounded river once supplied considerable hydroelectricity for local development, the resulting decimation of the fisheries heavily impacted the Lower Elwha Klallam people and had widespread consequences for the entire Elwha ecosystem. By the 1980s, structural safety issues concerning the dams had also surfaced. Mounting public pressure to remove the dams finally prompted Congressional action in 1992, mandating complete restoration of the river.

Demolition of the 108- and 210-foot-high dams will begin in September and take up to 3 years to complete. An estimated 24 million cubic yards of sediments trapped behind the structures will be released in stages, the majority of it naturally redistributed within the river's historical floodplain. “We'll be closely studying the short-term effects of this massive influx of material into river and coastal marine waters, as well as the ecosystem's long-term response to a more natural sediment supply”, explains Jeffrey Duda, of the US Geological Survey (Seattle, WA).

Nearly 20 years' worth of scientific data – on the river corridor and on the effects of the dams on local natural processes – will provide a baseline for tracking ecosystem recovery. “One of the biggest questions is how recolonization by the five historically abundant salmon species will unfold”, Duda continues. Not only are salmon important prey for carnivores, but their decaying carcasses enrich streams and forests with marine-derived nutrients. “Whether the salmon will return in numbers sufficient to reinvigorate this ecosystem service and produce measurable changes remains to be seen”, he adds.

As dams continue to deteriorate nationwide, society will increasingly face the difficult choice between investment in rebuilding and upgrading or removing them entirely. The Elwha restoration project promises to provide an important case study to help inform those decisions.

Small farms reap conservation rewards in Kenya

Jen Fela

Through a Payment for Environmental Services (PES) scheme, piloted by WWF Kenya (Nairobi) and CARE Kenya (Nairobi), small-scale farmers in the Lake Naivasha basin are rewarded by the Lake Naivasha Growers Group for conservation practices that result in enhanced water quality for large-scale commercial flower growers around the lake. Lake Naivasha's horticulture industry – along with agriculture, tourism, and geothermal power production – supports the livelihoods of over half a million people living within its basin, according to the World Agroforestry Centre (Nairobi, Kenya). But poor land-use practices have caused deterioration in the quality of the region's water, threatening the health of the only freshwater lake in the Great Rift Valley in Kenya.

Under the PES scheme, upstream small-scale farmers are encouraged to implement soil and water conservation measures by terracing, planting income-generating and water-conserving tree species, and protecting the riparian zone, to improve the lake's water quality. In return, downstream water consumers pay a fee to the upstream farmers for their efforts.

Figure 2.

Farmer Joseph Mangara (left) discusses the conservation material Napier grass with CARE Economist Obadiah Ngigi (right).

Although this PES program began in 2007, the first opportunity for monitoring and evaluation of the scheme came earlier this year. According to the WWF International Report (2011) entitled Shared Risk and Opportunity in Water Resources: Seeking a Sustainable Future for Lake Naivasha, “Water users around the lake were able to influence the land-use practices of smallholder farmers in the upper catchment by sharing knowledge and promoting more sustainable agriculture practices that have led to tangible welfare increases”.

Robert Ndetei, WWF Project Coordinator (Naivasha), says that these “tangible welfare increases” include increased household income for small-scale farmers. “In addition”, says Ndetei, “the sellers have received extensive capacity building on soil and water conservation, as well as agribusiness. The capacity building is not limited to sellers only, but to all basin stakeholders. The incentives to the sellers have long-term benefits to business, livelihoods, and nature conservation.”

Ndetei continues, “The current scheme is the only one of its kind in sub-Saharan Africa. It links livelihoods to conservation and demonstrates watershed downstream–upstream linkages; those who benefit from conservation recognize and reward those who bear the conservation burden, and, in demonstrating natural resource conservation, the program secures economic investment”.

Faithful warm up to global warming

Alison Gillespie

Although the media often likes to portray church-goers as climate-change skeptics, a small green movement has taken hold in many houses of worship in the last few years. The Canon Reverend Sally Bingham, an Episcopalian from California, is perhaps one of the most visible leaders of this movement. She has called climate change “the greatest moral issue of our time”. Scientific research presented about the changing global environment inspired her to reach out to religious leaders of other faiths.

Believing that almost all religions have a “mandate to be good stewards of natural resources”, Bingham and clergy from around the country have started a non-profit organization to address the issue literally from the ground up. Working with leaders from all the mainstream religions in the US, including Jews, Hindus, Buddhists, and Muslims, as well as other Christian denominations, the “Regeneration Project” aims to help congregations “green their sanctuaries” and reduce their carbon footprints. To date, more than 10 000 houses of worship have signed on, and have received guidance about projects such as purchasing energy-efficient appliances, greening their grounds-keeping programs, and installing energy-efficient windows.

Figure 3.

Rev Jered Weber-Johnson blesses the solar panels at St Alban's, Washington, DC.

St Alban's, a large, historic church in Washington, DC, was one of those congregations; their installation of 76 rooftop solar panels last fall was so well-received that the rector of the church, Jered Weber-Johnson, proudly refers to them as a “new kind of stained-glass window”. He told reporters present at the panels' unveiling and blessing that he hoped the panels would both save energy and inspire people in a manner similar to the colorful windows inside the building.

Andrew Gunther, who oversees the Center for Ecosystem Management and Restoration in Oakland, CA, is one of many scientists who have acted as advisors for the Regeneration Project. He thinks that the effectiveness of religious leaders at disseminating climate-change information is astounding. “They have been very successful at bringing the topic to people for whom the IPCC reports don't seem to have the same level of motivation”, he concludes.

Afghanistan's war-torn wildlife

Virginia Gewin

Despite 30 years of armed conflict, increased hunting pressure, and deforestation, large mammals appear to be enduring in Afghanistan's province of Nuristan. The findings (Oryx 2011; doi:10.1017/S00306053 10000517) provide the region's first wildlife survey since 1977.

Given the security risk to foreigners in Nuristan, the scientific team – funded by the New York City-based Wildlife Conservation Society (WCS) – trained local community members to conduct transect and camera-trap surveys, as well as to collect scat samples for DNA analyses.

In addition to evidence of persistence by species known to inhabit the region – including the Asiatic black bear (Ursus thibetanus), gray wolf (Canis lupus), and red fox (Vulpes vulpes) – the survey also found evidence of the common palm civet (Paradoxurus hermaphroditus) in Afghanistan. Yet environmental degradation has taken a toll. “We found little to no evidence of the species that are of greatest conservation concern in the region – musk deer [Moschus cupreus], markhor [Capra falconeri], or snow leopard [Uncia uncia], for example”, says Kara Stevens, one of the authors of the study and now a graduate student at Michigan State University (East Lansing, MI). It was unclear, however, whether the lack of evidence for these species is due to dwindling populations or to the difficulty of traveling to remote areas of the province.

What is clear from satellite-based imagery is that Nuristan's forest cover has decreased dramatically in recent decades. “The big concern is that uncontrolled hunting and deforestation will drive species to local extinction – which can happen quickly”, warns Peter Zahler, WCS Deputy Regional Director for Asia.

Forests are among the first casualties in conflict-ridden areas, given the need for cooking fuel and building materials, explains Joseph Dudley, a wildlife ecologist with the University of Alaska at Fairbanks, who has studied the effects of war on wildlife. That any forest or large animals are left in Nuristan at all is somewhat surprising, he admits, adding that the type of data obtained in the WCS survey is crucial to establish short- and long-term conservation goals in Afghanistan.

Zahler notes that WCS has been working with local communities to manage resources properly. Adds study coauthor Alex Dehgan, Science and Technology Adviser (US Agency for International Development, Washington, DC), “Over 80% of the population is dependent on natural resources for survival; they are very supportive of conservation activities, given their innate connection to the natural world”. That support is crucial. “Conservation efforts not only protect wildlife, but improve governance and provide economic stability for local communities”, concludes Stevens.

E coli muddying issues of water quality and food safety

Alison Gillespie

This summer, as a large part of the US suffers through a serious drought, irrigation has once again been extensively used to water crops. To many, it seems like a modern miracle that crop management and technology have become so advanced. However, when some microbiologists look out over the huge metal frameworks spraying the land with water from ditches, rivers, streams, and ponds, they think about bacteria. Specifically, they worry about how little is known about the pathogen Escherichia coli, and about future food safety.

Recently, a team working with the US Department of Agriculture's Agricultural Research Service in Beltsville, MD, proved that E coli could overwinter in the bottom sediments of creeks and streams. Led by Yakov Pachepsky, the researchers also demonstrated that non-pathogenic strains of the bacteria lived longer when levels of organic carbon and fine sediment particles were relatively high. In addition, the team discovered that E coli's survival rate was less likely to be affected by water temperatures than was previously thought. “If we do have reservoirs of microbes in bio-films and slimes, and those waters are used in irrigation systems, then we need to evaluate them. Do they need monitoring? Is there a health risk?”, asks Pachepsky.

Ron Turco, a microbiologist from Purdue University (West Lafayette, IN), agrees. “The whole notion that these pathogens die is wrong. They hang around”, he says. If, for example, the water pulled from an irrigation ditch is used on a “soft crop”, such as berries, it could potentially mean that there's an undetermined food safety risk that isn't being assessed. What is also problematic, Turco continues, is that E coli's behavior in open-system environments is still very poorly understood. As more knowledge is gained, it could be that regulations based around die-off will need to be re-evaluated.

In addition to irrigation issues, any new information about the bacteria's ability to live in stream sediments could also have a major impact on urban and suburban water-quality management, given that rules governing sewage spills and runoff from agricultural areas rely heavily on measurements of E coli from aquatic samples. Not many people are interested in mud, but it could change our conception of water quality. “There may be mistakes in management because we are not taking into account these variables in sediment”, Pachepsky warns.

On the origin of (an invasive) species

Pete Mooreside

As the first exotic fishes known to have established breeding populations in the western Atlantic Ocean, two species of venomous Indo-Pacific lion-fish (Pterois volitans and Pterois miles) have achieved a notorious distinction. For more than a decade since their appearance along the Atlantic coast of Florida, these marine predators have dramatically expanded their non-native ranges (http://fl.biology.usgs.gov/lionfish_progression/lionfish_progression.html). Although it's tricky to tell the species apart at first glance, the unmistakable success of the lionfish as an invader is, however, likely due in part to its reproductive abilities; each mature female is capable of producing millions of viable eggs in a typical year, and spawning occurs frequently and regardless of season.

Given the widespread popularity of lionfish among saltwater aquarium enthusiasts, it is speculated that the initial Pterois introduction resulted from several deliberate releases of captive animals. But marine biologist Ricardo Betancur (George Washington University, Washington, DC) wanted to learn more about the invasion's backstory. “We were particularly interested in determining whether non-native lionfish populations – observed at locations as far south as northern South America – originated as a result of multiple independent introductions across the western Atlantic, or if they shared a common introduction origin with the invasive populations established off Florida over 10 years ago.”

Figure 4.

Invasive lionfish (Pterois volitans) at Santa Marta, Colombia, in the southern Caribbean Sea.

To that end, Betancur and colleagues analyzed mitochondrial DNA sequences obtained from 755 individuals collected at six locations in the Greater Caribbean and off Bermuda, including four previously unsampled areas (J Biogeogr 2011; doi:10.1111/j.1365-2699.2011.02496.x). Among other revelations, the authors found a striking absence of genetic differentiation in both lionfish species across the region, when compared with relatively greater variation in the allele frequencies observed in native Pterois populations. According to Betancur, this suggests that, while the origin of the invasion may be multiple aquarium releases, there's a single epicenter off Florida.

Ultimately, as the lionfish invasion escalates, so does the apprehension of scientists and resource managers, who are concerned about trophic-level effects and other consequences for native reef (including commercially valuable) species. Despite the negative ramifications of biological invasions, such events offer important opportunities for research. “They provide a natural experiment to study marine connectivity and dispersal patterns in real time”, Betancur explains.

Mammals pitch in to help pitcher plant

Anna Trochim

In the mountains of Malaysian Borneo, a unique relationship between a pitcher plant (Nepenthes rajah) and two mammals (the mountain tree shrew, Tupaia montana, and the summit rat, Rattus baluensis) was recently discovered by three Monash University scientists, Rohan Clarke and Melinda Greenwood (Victoria, Australia) and Charles Clarke (Selangor, Malaysia). These researchers have uncovered a mutualistic interaction among these three species, in which both mammals feed on the nectar produced by the pitcher plant, while in turn providing it with nutrients by defecating into the urn-shaped leaf organ also used to trap arthropods (PloS ONE 2011; doi:10.1371/journal.pone.0021114). According to Rohan Clarke, this relationship is “not only a highly specialized resource mutualism between mammals and a carnivorous plant, it is the only example of a mammal–pitcher-plant association that involves two different species of mammals”.

Figure 5.

A mountain tree shrew (Tupaia montana) feeding on the nectar of the giant Bornean pitcher plant (Nepenthes rajah).

The study site is not a typical tropical habitat. “Working in the ‘jungles of Borneo’ conjures up images of hot, humid, sticky conditions”, says Rohan Clarke, “with water constantly dripping from the canopy due to ever-present showers and storms”. Although this habitat is wet, the conditions are not suitable for supporting a rich array of biodiversity. “In montane habitats, resources are often lacking, due to lower abundance and diversity of arthropods and fruiting trees”, explains Charles Clarke, “so Nepenthes could represent an important resource for the mammals during periods when other sources of nutrition are scarce”. In return, the pitcher plant gains an around-the-clock supply of nutrients, from the scat of mountain tree shrews by day and summit rats at night. This differentiation in feeding time allows the two mammals to “display niche separation through their diurnal/nocturnal foraging strategies”, says Greenwood.

This discovery is important in understanding ecological interactions and evolutionary adaptations. “The relationship between tree shrews, rats, and Nepenthes species has enormous importance for scientists who are interested in the evolution of animal–plant mutualisms”, explains Charles Clarke. “Likewise, the subtle morphological changes in the plant – such as size, nectar production, and lid angles – were all that was required to convert an arthropod trap into a dining table and toilet for rats and tree shrews.”

Tracking the wildlife trade electronically

Jen Fela

During late June in Managua, Nicaragua, more than 30 representatives from Central and South American countries, including Brazil, Costa Rica, and Guatemala, met to discuss the replacement of paper permits with an electronic tracking system to help guarantee a “legal, sustainable, and traceable international wildlife trade”, according to a press release by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). The meeting was jointly organized by the CITES Secretariat (UN Environment Programme, Geneva, Switzerland) and the Central American Commission on Environment and Development (Antiguo Cuscatl, El Salvador), and supported financially by the US Department of the Interior's Technical Assistance Program (Washington, DC).

John Scanlon (CITES Secretary-General, Geneva, Switzerland) explains that the “import, export, re-export, and introduction” of approximately 34 000 species and derived products included on the CITES list of protected species must be monitored and conducted through the use of permits issued by the appropriate authorities. Currently, most of those permits are on paper. Scanlon says that the new goal is for users to complete the entire permitting process electronically, accessing the system remotely through a single entry point (such as a website) to fulfill all import, export, and transit-related regulatory requirements. Scanlon explains the advantages of an electronic system: “An e-permit is much more difficult to falsify. It is also much easier to trace back to the issuing authority to verify its authenticity.”

Additional benefits include ensuring sustainable trade and facilitating legal trade. Scanlon continues, “With paper permits, there can be a 2-year lag from the time the trade took place to when it is entered in the CITES Trade Database, which is used to ascertain levels of trade. If permits are electronic, it would be possible to register the data in the CITES Trade Database immediately, creating an up-to-date database that is much more valuable to decision makers. This is a major contribution toward efforts to conserve biodiversity and ensure that resources are used sustainably in support of local livelihoods”.

This move comes on the heels of major ivory seizures in China, Thailand, Vietnam, and Kenya in recent months, and a surge in rhinoceros poaching in South Africa during the first half of 2011, according to TRAFFIC International (Cambridge, UK) and WWF International (Gland, Switzerland). The CITES Secretariat hopes to establish similar e-permitting systems in Asia and Africa by next year.

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