Tuesday, 29 November 2011

The different personalities of urban and rural song sparrows

Just as humans have particular traits that may indicate whether they hail from the city or the country, so, too, do some wildlife species. Compared to their rural counterparts, for instance, urban birds may be slightly larger, have lower levels of stress hormones, sing more during the middle of the night (because of artificial lighting), and sing higher-pitched songs (to avoid being "masked" by human noises). A recent study on song sparrows (Melospiza melodia) suggests that city birds may also have different personalities than their country cousins.

(Song sparrow, Melospiza melodia)

The research was conducted by collaborators from the College of Charleston and Western Carolina University. Their work followed up on a previous report that rural birds in Pennsylvania displayed different "behavioral syndromes" (or suites of related behaviors--what we might colloquially refer to as "personalities") than urban birds in North Carolina. The researchers wished to know whether this might represent widespread differences between city and country birds, or whether the result was merely driven by geographical differences between Pennsylvania and North Carolina animals. They hoped that the answer to this question might be useful in explaining why some species do so well in urban areas while others fail, and in predicting which animals might adjust to future introductions of human disturbance.

Rather than measuring all behaviors of the focal birds, the researchers examined just two: boldness and aggressiveness. The first is an indication of an animal's willingness to engage in risky behaviors such as exploration and approaching a foreign object--two activities that have obvious consequences in human environments that offer new and different stimuli relative to birds' natural habitats. The second characteristic is aggressiveness, which, in many animals, is correlated with boldness. Specifically, animals that are bolder often get themselves into sticky situations where it pays to also be more aggressive, else suffer the consequences of attacks by rivals or predators. Where species are expanding their ranges, it is common to see more aggressive individuals, indicating that this trait is advantageous in gaining a foothold in novel habitats--such as anthropogenic environments.

(Typical habitat in Crawford County, PA)

For the current study, the researchers measured both the boldness and aggressiveness of male song sparrows in Crawford County, Pennsylvania. "Rural" birds were those living on State Games Land, while "disturbed" birds were those living in two nearby towns (Linesville and Conneaut Lake). In order to quantify the birds' boldness, the researchers performed a "flight initiation distance" experiment. This consisted of having a pedestrian approach each male at a standard rate, then measuring how close the person got to the bird before it took flight; shorter distances indicate bolder males. In order to quantify aggressiveness, the researchers played each male a recording of another male's song, simulating a territorial intrusion. An observer then measured how close each male approached the speaker; more aggressive males were those who went nearer to the "intruder."

Urban males were both bolder and more aggressive than their country counterparts; further, males from Linesville and Conneaut Lake showed very similar responses, indicating that, to birds at least, there may not be significant differences between specific urban locations (even when, as here, the population size differs noticeably). Across all song sparrows in general--regardless of where they lived--aggression and boldness were positively correlated. However, when city and country birds were analyzed separately, this correlation only held true for the latter: In the country, males are generally as aggressive as they are bold; in the city, though, it is not uncommon to find males that are bold and passive or shy and aggressive. 

 (Song sparrow showing an aggressive response towards a speaker broadcasting another male's song)

Importantly, these patterns were not caused by reduced variation in one type of habitat; in both settings, the ranges of values observed for each trait were similar--the major difference was how those traits co-occurred, or formed personalities. So what is driving this "breakdown" in song sparrow behavioral syndromes in urban areas? One important factor may be predation--which may occur at different levels, or involve different types of predator, in urban and rural areas. One of the biggest costs of being too bold is accidentally exposing yourself as a potential snack, so variations in predator-related factors could determine whether it is helpful or harmful to be inquisitive and exploratory. Other major differences between urban and rural areas have to do with the habitat--in terms of how much there is, how it is structured, how many other individuals are packed into the same unit of distance, and whether there is supplemental food being provided by humans. These variations may favor different levels of aggressiveness, since birds that can utilize these different resources side by side with their neighbors, without getting into any arguments over what belongs to who, may be more successful.

Additional studies will be needed to determine the exact mechanisms of the patterns seen in this study. Long-term research will be useful in uncovering whether these different personalities indicate human-driven evolution (since these behavioral characteristics are genetic traits that can be passed from one generation to the next), or whether they are yet another example of the amazing behavioral flexibility of some species of wildlife. One of the most surprising outcomes of the study is that these strong inter-population differences were observed even when the "urban" birds lived in quite small towns (with populations of ~700 and ~1100). Thus, it is clear that even relatively minor levels of human influence can have a noticeable impact on animal behavior.

For supplementary images associated with this post, visit the Anthrophysis pin board at Pinterest.

Scales, J., Hyman, J., and Hughes, M. 2011. Behavioral syndromes break down in urban song sparrow populations. Ethology (117):887-895.

Thanks to the following websites for providing the images used in this post:

Monday, 28 November 2011

Anthropogenic noise prompts both short- and long-term changes in birdsong

As increasingly more bird species are found to alter their vocalizations in the presence of anthropogenic noise, researchers are developing more detailed questions about the process by which this behavioral modification occurs. One of these questions focuses on the time scale over which these noise adjustments happen: Do birds in noisy areas only vary their vocalizations during specific noisy events, or do noise-disturbed birds always sing different songs than their undisturbed counterparts? Results of a recent study by collaborators from the University of Ottawa and the University of Windsor suggest that, in one species at least, the answer is “both.”

That species is the red-winged blackbird, Agelaius phoeniceus, which is often found living in marshes alongside noisy roads. Singing male blackbirds produce songs across a 1-5 kHz frequency range, the lower end of which overlaps with the frequencies dominated by anthropogenic noise. Songs comprise a few introductory syllables and a broadband trill; the latter song element appears to be the most important part of the song, as it facilitates species recognition. In the current study, the researchers investigated whether, and how, anthropogenic noise influences the structure of these trills.

(A male red-winged blackbird, Agelaius phoeniceus)

The study involved two separate experiments. In the first, the researchers located males in marshes that are not exposed to human noises. After placing a set of speakers near each territorial male, the scientists then recorded songs produced against a background of no noise (a silent control treatment) and 89-dB, low-frequency white noise (approximating traffic). This allowed them to investigate whether individual birds were capable of “real-time” shifts in response to increasing levels of background noise. In the second experiment, the researchers compared songs produced by males in undisturbed, quiet marshes with those performed by roadside males singing in temporarily quiet periods. This part of the study was aimed at determining whether all blackbirds sing similar songs during quiet conditions, or whether long-term exposure to generally louder ambient noise environments leads disturbed birds to make permanent shifts in their vocalizations.

Previous studies have shown that birds may alter a variety of song parameters in response to noise. Thus, the authors of the current study measured several different variables associated with each recorded trill: duration, minimum frequency, maximum frequency, and energy distribution of the spectrum (in other words, which frequency the birds produce at the highest amplitude). They also performed two types of validation in order to make sure that their study techniques were sound. The first was a basic comparison of average environmental noise levels at roadside versus “undisturbed” marshes; the former were verified as louder than the latter (~65.8 dB compared to ~51.7 dB). The second validation investigated whether the experimental playback condition may have artificially influenced results because of the difficulty of accurately measuring birdsong against a background of white noise; the experimental setup again passed the test, as the results indicated that the patterns measured here were not merely an artifact of study design.

(Roadside marshes provide habitat for red-winged blackbirds--and may also provide considerable levels of background noise)

For the first experiment, the researchers analyzed 140 songs from 20 male blackbirds. Of all the song characteristics measured, only one was influenced by the introduction of experimental noise: entropy, which decreased in response to noise. This variable is a measure of song “randomness;” purer tones have a value close to 0, while white noise has a value closer to 1. This entropic shift resulted from the birds’ concentrating their spectral energy at lower frequencies. The second experiment, which analyzed 344 songs from 63 males, found very similar patterns as those observed in the first half of the study. The only variable associated with habitat type was trill entropy, as trills at roadside marshes were more tonal than trills at undisturbed sites, and, again, this was caused by a concentration of spectral energy at lower frequencies.

Taken together, the results of these two experiments indicate that red-winged blackbirds exposed to anthropogenic noise are capable of both short-term behavioral plasticity and maintenance of long-term behavioral differences, the latter of which may even be a sign of adaptation. Although this is the first report that tonality is influenced by human noise pollution, previous studies have shown that natural noise has similar effects (for instance, in large-billed leaf warblers, Phylloscopus magnirostris and several species of frog, all living near loud running water in the Himalayas).

(Large-billed leaf warbler, Phylloscopus magnirostris--another species that adjusts the tonality of its vocalizations in response to ambient noise)

Given all of the ways in which the blackbirds could have altered their songs, it is interesting to ponder why they focused only on entropy. Some possibilities are associated with the detectability of the signal: Higher frequencies attenuate more rapidly when transmitting through the environment, so the redistribution of spectral energy to the lower frequencies may enhance signal transmission. Additionally, narrow-band signals (such as pure tones) are easier to discriminate from background noise, making more tonal songs more receiver-friendly. Other possibilities are associated with the potential costs and constraints associated with non-entropy-related alternatives: Perhaps the birds’ morphologies prevent them from achieving some song qualities, or maybe it requires too much energy to produce certain types of songs. Of course, it is also possible that the manipulations measured here were merely a side effect of some other, unmeasured, variable.

Other important costs may be those associated with signal transmission and receiver discrimination. Even for the birds that manipulated their songs in the presence of noise, it is possible that these vocal acrobatics were not enough to prevent their songs from being masked by anthropogenic noise. If so, we might expect to see that males in noisier locations have more difficulty wooing females and/or producing successful broods. Depending on how the birds choose mates and habitats, it is feasible that noise could eventually drive the formation of different subspecies of blackbirds. All of these possibilities have serious conservation and management implications, causing the authors of the current research to recommend follow-up studies in the future.

Hanna, D., Blouin-Demers, G., Wilson, D.R., Mennill, D.J. 2011. Anthropogenic noise affects song structure in red-winged blackbirds (Agelaius phoeniceus). The Journal of Experimental Biology 214:3549-3556.

Thanks to the following websites for providing the images used in this post:

Sunday, 27 November 2011

Human-associated species dominate restroom bacterial communities

The results of a recent study characterizing microbial communities in public restrooms may be enough to change the ways of those who don't already wash their hands after using the toilet. The study found that restrooms are dominated by human-associated bacteria--particularly those from the skin, gut, and urinary tract. Although this is not particularly surprising, the "biogeography" of these species--or which surfaces they were most commonly found inhabiting--was a bit unexpected. While there were three distinct clusters of species (bacteria on or near toilets, those on the floor, and those on surfaces mostly touched by hands), there were also several groups of bacteria that were present on all surfaces. This includes gut and urine bacteria, which were found not only on the seats and handles of toilets, but also on sink faucet handles, soap dispensers, and even on the handles of doors leading out of the restroom--in other words, the areas touched after hand-washing has already been completed.

(Corynebacterium diphtheriae, an Actinobacteria)

The study, conducted by researchers from a variety of departments at the University of Colorado--Boulder, was not designed to produce results to frighten the squeamish, but to better understand the bacterial communities living inside human establishments. This has also been the goal of previous investigations, but those studies have generally relied on cultivation-based techniques that may fail to document the many bacterial species that cannot be grown in the lab. The current effort used a cultivation-independent technique known as barcoded pyrosequencing. This method was focused on 16 S rRNA, a highly conserved bacterial gene. Similar gene sequences from across the sampled communities can be clustered into "operational taxonomic units" (or OTUs, a bacterial equivalent of "species" that takes into account the unique way in which bacteria can share genes with each other) that can then be used to assign taxonomy and generate a phylogenetic tree.

In this case, the bacteria in question were sampled from 10 surfaces in each of 12 public restrooms (6 male and 6 female): door handles into and out of the restroom and restroom stall, faucet handles, soap dispensers, toilet seats, toilet flush handles, the floor around the toilet, and the floor around the sink. Bacteria in restroom communities were compared to those found in potential source locations, including the tap water flowing into the restrooms' sinks, soil that could be tracked in on shoes, and humans (from their skin, mouth, gut, and urine). The study also explored the similarity of bacterial communities on different surfaces within bathrooms in order to see whether certain types of bacteria typically cluster in particular areas.

(Streptococcus pneumoniae, a member of the phylum Firmicutes)

Although a total of 19 phyla were observed across all restroom surfaces, most samples were representatives from one of four phyla: Actinobacteria, Bacterioidetes, Firmicutes, and Proteobacteria. Interestingly, these were the same phyla identified by previous studies utilizing less powerful censusing techniques. Certain taxa were found on all surfaces. The most common of these were associated with human skin (Propionibacteriaceae, Corynebacteriaceae, Staphylococcaceae, and Streptococcaceae), which is not surprising given that they are known to be fairly hearty species that can survive for extended periods away from their preferred environment. More disturbing was the finding that some gut, mouth, and urine bacteria were also found on all surfaces--even on door handles leading out of the room.

The community-level analysis revealed that bacteria could be separated into three broad groups: those on the floor, those on toilet surfaces, and those on surfaces touched by hands. Floor surfaces had many low-abundance taxa and were the most diverse; these environments harbored an average of 229 OTUs, in comparison with 150 found in other areas. Occasionally, "floor species"--such as those typically found in soil--were also observed on toilet handles, indicating that some people were probably flushing with their feet in order to avoid touching germy surfaces. The most troubling observation was the "enrichment" of toilet seats with bacteria associated with the human gut; a high prevalence of these species could encourage outbreaks of intestinal illnesses.

Mouths (thankfully) were not major contributors to restroom bacteria. Neither was tap water running from the faucet. Ventilation systems and cleaning equipment were not sampled in the current study, and the authors admit that these could be important contributors to investigate in the future. Overwhelmingly, though, these results support previous findings that humans (in particular, our skin, gut, and urine) are the main source of bacteria in our environments. The patterns reported here also emphasize the importance of good hygiene in minimizing transmission of human pathogens: Even the cleanest person can pick up unfriendly bacteria by merely touching surfaces exposed to other individuals. Any readers feeling a bit disgusted about our species' cleanliness should take heart. While some of the bacteria may have been transferred directly to bathroom surfaces via contact with our skin, water splashing and aerosolization of particles during flushes are also likely culprits.

Flores, G.E., Bates, S.T., Knights, D., Lauber, C.L., Stombaugh, J., Knight, R., and Fierer, N. 2011. Microbial biogeography of public restroom surfaces. PLoS ONE: 6(11):e28132.

Thanks to the following websites for providing the images used in this post:

Saturday, 26 November 2011

Traditional farmland provides overwintering habitat for Spanish great bustards

We humans may be tempted to think that one farm is like any other, but at least one species of bird--the great bustard, Otis tarda--shows clear preferences for some agricultural areas over others. Specifically, overwintering female bustards seem to prefer traditional farmland habitat characterized by a mosaic of vineyards and olive groves, low human population densities, and minimal anthropogenic infrastructure. This preference differs from that shown during the breeding season, indicating that conservation plans drafted to protect this species--which is classified as "vulnerable" at national, European, and global levels--need to be more comprehensive than previously realized.

(A great bustard, Otis tarda)

These results were the product of a study performed by four collaborators from the Museo Nacional de Ciencias Naturales and the Universidad Complutense (both in Madrid). Spain, with more great bustards than any other country, contains approximately 60% of the global population of these birds. However, anthropogenic intensification in the Iberian Peninsula is a potential threat to this vulnerable species. Major worries include the construction of additional infrastructure, creation of agricultural monocultures, and replacement of traditional vineyards. Bustards are generally quite happy to live near humans during the breeding season, but, prior to the current study, little was known about their habitat preferences during the winter. Seasonal variation in habitat use might mean that current conservation plans do not adequately protect the species.

In order to evaluate great bustard habitat use, the researchers placed radio-transmitter backpacks on 68 females and tracked them for at least two years apiece. Females were sighted multiple times per season and GPS coordinates were collected for all locations where the females were present. These were used to determine each bird's breeding and wintering areas. Habitat surveys were then performed in order to characterize each area's topography (altitude, slope, surface undulation), climate (temperature, rainfall, amount of sunshine), land-use type (type and amount of farmland, pastureland, and/or vegetation), and human influence (distance to nearest road and urban area, road length, area of urban cover, human population density).

(A mosaic of Spanish vineyards and woodland)

Most females (77%) showed high fidelity to their wintering sites from one year to the next. Among those who migrated from a breeding site in one area to a wintering site somewhere else, 80% wound up in the same location: Mesa de Ocaña in North Toledo. Overwhelmingly, the birds chose wintering sites that were flatter, at higher altitudes, warmer, and less anthropogenically disturbed than their breeding sites. This final characteristic resulted from the sites' being farther from urban areas, containing lower human population densities and less human infrastructure, and possessing more mosaic (e.g., traditional) farmland.

The researchers also performed a wintering-ground-only analysis in which they compared habitat characteristics of settled areas to those of nearby unused areas. Although there were 9 traits that were significantly different between these two types of site, the most important predictors of bustard habitat choice were amount of vineyard and level of substrate diversity. Specifically, the birds preferred areas with more vineyard habitat and more uniform substrate--the latter of which was generally caused by a lack of trees.

(Great bustard displaying during the breeding season)

One of the most exciting results of the study was the identification of the North Toledo wintering site; this is not only the most important great bustard wintering site in Spain, but, with flock sizes exceeding 200 birds and with densities of 6.3 birds per square kilometer, the most important overwintering site for this species in the world. However, the birds' clear preference for a less disturbed wintering area is a bit worrying given the generally high rates of anthropogenic habitat alteration in the region. 

Female bustards appeared particularly enamored of traditional vineyard areas, where vines are shorter and more dispersed, and where there are fewer humans nearby. This type of agricultural area is increasingly being replaced with modern vineyards characterized by wire-supported vines where the plants are higher and more human workers are required to regulate irrigation equipment. The researchers report that nearly 44,000 hectares of traditional vineyards in the region have already been converted, with plans to convert another 100,000 hectares in the near future. This could reduce habitat not only for great bustards, but also for other endangered species such as the little bustard (Tetrax tetrax), black-bellied sandgrouse (Pterocles orientalis), and pin-tailed sandgrouse (Pterocles alchata).

(Little bustard, Tetrax tetrax)

Although it is heartening to see wildlife happily utilizing certain human-altered habitats, the authors of the study are worried about the efficacy of the Special Protection Areas (SPAs) created to provide protected habitat for endangered species like the great bustard. Specifically, the researchers state that regional authorities associated with the SPAs have actively supported agricultural transformation and infrastructure construction--two habitat modifications that are particularly likely to make sites less bustard-friendly. Thus, they hope that their new data on the birds' winter habitat preferences can be used to design more appropriate conservation and management plans that protect the birds and their homes year-round.

For supplementary images associated with this post, please visit the Anthrophysis pin board on Pinterest.

Palacín, C., Alonso, J.C., Martín, C.A., and Alonso, J.A. 2011. The importance of traditional farmland areas for steppe birds: a case study of migrant female great bustards Otis tarda in Spain. Ibis, online advance publication.
Thanks to the following websites for providing the images used in this post:

Friday, 25 November 2011

Fishing-related species declines impact provisioning of ecosystem services

As more and more studies find that human disturbance impacts some species more than others, ecologists are shifting their focus to the next logical research question: What is the consequence of this selective disruption of wildlife communities? By interacting with other species and with the habitat in general, many species have significant impacts on their environments; if their numbers are reduced, or if they are eradicated altogether, there could be widespread and/or long-term effects on the ecosystem.

This possibility was recently explored by collaborators from James Cook University and King Abdullah University of Science and Technology, who performed a large-scale study of parrotfish abundance, diversity, and ecological impacts at coral reefs in the Indian and Pacific Oceans. Parrotfishes are so named because of their parrot-like beaks, which they use to scrape algae off coral surfaces. This unique grazing mechanism often grinds off pieces of the corals themselves, in a process known as "bioerosion." One species of parrotfish even eats corals directly. While feeding, the fish ingest sediments that have collected on the reef, which they then spit out elsewhere. Cumulatively, these four activities--grazing, bioerosion, predation, and sediment removal--can have noticeable impacts on coral reef biodiversity and habitat structure. Different parrotfish species perform these ecosystem services at different levels and rates, and human activities (hunting, in particular) target some parrotfish species more than others. Thus, it seemed likely that anthropogenic disturbance might have ecosystem-level impacts by altering the balance of parrotfish species at coral reefs.

(Princess parrotfish, Scarus taeniopterus)

To investigate this possibility, the researchers collected data from 18 reefs, from Mauritius to Tahiti, across a disturbance gradient. Just over half the reefs continue to host local fishermen, while 2 have been closed to fishing for 18 years, and another 4 are partially protected. At each site, the researchers documented quantities and sizes of different species of parrotfishes. Since each species acts in predictable ways, in terms of which ecosystem services it performs and at what rate, the census data could be used to calculate the total amount of grazing, bioerosion, predation, and sediment removal performed at each reef. These values were related to 3 indices of human disturbance: population densities on the nearest adjacent landmass, regional per capita incomes, and extent of environmental management. In order to control for the possibility that some regions (e.g., near Tahiti) might naturally have different parrotfish populations than other regions (e.g., near Mauritius), the scientists also documented regional variations in biodiversity and richness; by included these variables in their analyses, the researchers were able to make comparisons of sites across the entire geographic range studied here.

The most heavily fished reefs had much lower numbers of large (>25 cm) parrotfishes than reefs with little or no fishing (3.6% vs. 43-67% of fish). The disparity between sites was even more obvious when the researchers considered biomass, rather than commonness: The most lightly fished reefs had ~50 times the biomass of large parrotfishes than that found at the more heavily fished reefs. Some parrotfish groups were particularly scarce at these highly fished sites; members of the genus Bolbometopon, as well as small species in the genus Chlorurus, were especially rare. However, some species were less affected by humans. Members of the Scarus and Hipposcarus genera were neutrally impacted by anthropogenic activities, while smaller species in the genus Chlorurus actually showed positive trends in areas where fishing was heaviest.

(Green humphead parrotfish, Bolbometopon muricatum)

At reefs where fishing was permitted, even small human population densities (16 people per square kilometer) on the nearest landmass were associated with nearly complete disappearance of large-parrotfish-related functional roles--predominantly bioerosion and coral predation--at the reefs. However, where heavy fishing has depleted larger species, smaller parrotfish appear to be doing quite well. When they feed, these animals simultaneously remove turf algae and the sediments they contain; thus, grazing and sediment removal services are generally intact even at the most disturbed sites. These activities, unlike bioerosion and coral predation, varied quite a bit even among sites that had similar human densities. This suggests that non-anthropogenic factors, such as local fluctuations in richness, are a more important predictor of the abundances and activities of the parrotfish that perform these services.

This is not the first study to document declines of large individuals in heavily fished areas. However, this is one of the first studies to demonstrate that this pattern can be seen not just within species, but also among them and, further, that this has significant effects on ecosystem processes. The ability of parrotfishes to perform bioerosion, coral predation, grazing, and sediment removal services depends not only on the abundances of particular species, but also on their morphologies--in particular, body and jaw size, which influence feeding biomechanics. Smaller fish are physically incapable of filling the gaps left when larger fish are wiped out, and this could ultimately lead to a reshaping of the local coral reef habitat, as algae and sediment accumulate, and formerly-predated species of corals begin to increase in number.

(Women cleaning parrotfish caught by local fishermen.)

During the study, the researchers also interviewed local fishermen, with a particular focus on those who have been active for several decades. Time and again, fishermen pointed to the 1960's and 1970's as a time when noticeable parrotfish declines occurred. This is the same period over which new fishing technology--goggles, masks, rubber-powered spearguns, underwater torches, and SCUBA equipment--became available for widespread use. Interestingly, although human population density--a proxy for how many people are likely to be fishing at a given reef--was the dominant anthropogenic factor influencing parrotfish abundances, the other two variables are likely also important: Intact ecosystem processes were only recorded when low population density was coupled with high income and more habitat protection.

The results of the study suggest that protecting or encouraging the growth of parrotfish populations might improve the long-term health of coral reef ecosystems. In areas where the largest species are particularly scarce, corals may be more vulnerable to "environmental stochasticity"--unpredictable events such as cyclones or bleaching. Another worry is algal blooms. Smaller parrotfish are physically unable to consume mature stands of macroalgae, which means that reefs without larger species may be particularly susceptible to algal invasions. These are not concerns that apply only to the 18 reefs investigated in the current study. The authors believe that the ecosystem dynamics recorded here probably reflect relationships among many species and species groups in a diverse array of environments. In order to investigate whether this is the case, additional researchers in a variety of habitats will need to shift their focus, measuring not just how anthropogenic activities may influence the numbers and types of species present, but also how this alters the ecosystem services that are performed in these areas.

For supplementary photos associated with this post, please visit the Anthrophysis pin board at Pinterest.

Bellwood, D.R., Hoey, A.S., Hughes, T.P. 2011. Human activity selectively impacts the ecosystem roles of parrotfishes on coral reefs. Proceedings of the Royal Society B: online advance publication.

Thanks to the following websites for providing the images used in this post:

Monday, 21 November 2011

A Buddhist leader's thoughts on conservation

Although the fundamental tenets of many religions may have some bearing on conservation activities, the relationship between spiritualism and environmentalism is perhaps most obvious in the case of Buddhism. The close ties between Buddhism and conservation-mindedness were recently described by His Holiness the 17th Gyalwang Karmapa, Ogyen Trinley Dorje, in an essay published in the 25th anniversary edition of Conservation Biology. The Karmapa is the head of the Karma Kagyu school of Tibetan Buddhism, and is regarded by his millions of followers as the 17th incarnation in a 900-year old lineage. In addition to his role as spiritual leader, the Karmapa is also an environmental activist. He traces his "love for nature and dedication to protect the environment" to being asked, as a child, to plant a sapling at the source of a spring that was drying up during a drought. Even then, he writes, he was "considered an unusual child," whose "daily joy consisted of exploring the nearby mountains" and seeing wild animals at close range. The growth of the sapling marked the sprouting of his interest in preserving the wilderness.

(H.H. 17th Gyalwang Karmapa, Ogyen Trinley Dorje)

The Karmapa writes that Buddhism, with its emphasis on diversity and the connectedness of animate and inanimate beings as two parts of one whole, is closely related to the environmental movement. The "essence of Buddhism," he says, "lies in the union of compassion and emptiness." "Compassion," in this case, is an understanding that each person benefits from the "hopes, dreams, and labor" of people we often never meet--those who grow our food, make our clothes, purify our water, and so on. It is the understanding that no one thing exists by itself alone, or can survive alone. "Emptiness," on the other hand, is a lack of "self-nature." The self is "empty," writes the Karmapa, because it is impermanent and intangible--"constantly moving, absorbing, and shedding." Rather, the self--whatever it feels and accomplishes--is part of a larger entity, a conglomeration of all phenomena everywhere.

According to Buddhism, ignorance of the "empty nature of the self," together with rejection of compassion, cause us to be egotistical; this, in turn, has led us to degrade the environment. In fact, we and the things that are most closely related to us are not any more valuable than anything else, the Karmapa writes. When we view the world as "me" and "other than me," we are denying a fundamental relationship to the Earth--a "shortsightedness" that "blinds us to the relation between our activities and their longer-term consequences." Although conservation and sustainability have especially poignant meanings in a religion that incorporates ideas of reincarnation, the Karmapa writes that this is not the only reason that Buddhism goes hand in hand with environmentalism. He equates conservation with the human rights movement. Not only did the latter cause a "revolution in our thinking" that reconfigured many societies within the space of just a single century, but it also arose from individual people who believed that they could make an example of themselves for everyone to follow. These Buddhist ideals--viewing all as equals and "being the change you wish to see" (to quote Gandhi) apply to wildlife and natural ecosystems as well as to humans.

(Representatives from the Khoryug monasteries working to clean the Bodh Gaya Main Temple and nearby streets)

The Karmapa advocates making connections between conservation challenges--deforestation, climate change, overharvesting--and individual choices made on a daily basis. If we see environmental issues as stemming from the multitude of activities that we engage in each day, we are more likely to feel that we can control them. His Holiness hopes that people can "accept that we are not isolated individuals but instead one whole made up of all life on Earth." This should prevent "[indifference] to the suffering and ills that occur here." However, he also acknowledges that this is not easy; most of us have other important decisions to make and worries to face on a daily basis, leaving us little time and energy to address issues that do not necessarily seem immediately pressing or important.

The Karmapa believes that our major goal should be "[empowering] everybody to protect the environment. This can be achieved by "[breaking] through barriers and [building] bridges"--a sentiment echoed in many of the essays in Conservation Biology's anniversary issue. Working together, perhaps we can minimize our energy intake, learn to live more simply and with less waste, and "reassess what we mean by success"--perhaps shifting emphasis from personal affluence and economic development to other values "such as sharing, compassion, and peace."

These goals, the Karmapa points out, are consistent with all major religions, which share the same founding principals: living simply, acting compassionately, and treating each other with kindness. No religion says that we should destroy the Earth, and, in fact, many religions include messages about the importance of stewardship of nature. The Karmapa has been trying not only to talk the talk, but also to walk the walk. In 2009, he founded KHORYUG (the Tibetan word for "environment"), a network of Tibetan Buddhist monasteries and nunneries that are focused on preserving the Himalayas. He considers these environmental efforts an "evolution" from "enlightened aspiration" to "enlightened activity"--a worthy progression not only for devout Buddhists, but for us all.

Dorje, Ogyen Trinley, H.H. 17th Gyalwang Karmapa. 2011. Walking the path of environmental Buddhism through compassion and emptiness. Conservation Biology 25(6):1094-1097.

Thanks to http://www.khoryug.com/ for providing the images used in this post.

Saturday, 19 November 2011

Land conservation is encouraged by childhood experiences in the outdoors

Conservationists are increasingly interested in finding out why people engage in environmental activities, and a growing body of literature suggests that pro-nature ideals among adults are fostered by activities that they engaged in during their childhoods. A recent study of Indiana landowners supports this theory and emphasizes the significance of unstructured outdoor play over more formal educational activities.

The research, conducted by collaborators from Earlham College and Indiana University, focused on a group of landowners who elected to participate in conservation easements (CEs) for portions of their property. CEs are legally binding agreements that maximize the conservation value of land by limiting particular activities, such as development and industrialization. Despite the importance of this conservation tool throughout the US, little is known about what--other than potential tax breaks--inspires people to participate in CEs. Thus, the current research was conducted in order to explore the conservation mindsets of CE landowners and to determine how their attitudes towards environmentalism were formed.

(Border of a conservation easement in Virginia, USA)

To do this, the researchers used a two-phase survey process to collect both quantitative and qualitative data. During the first phase, they conducted phone interviews with CE adopters in order to identify common themes associated with people who engaged in this particular conservation behavior. Within 16 interviews, the researchers noted a "saturation" of concepts, terms, and phrases; in other words, the interviewees had seemingly exhausted the list of potential reasons why someone might be interested in becoming involved in a conservation easement. Four main types of inspiration consistently emerged as "significant life experiences" (SLEs) that fostered an interest in land preservation: the impact of family and friends, unstructured time spent outdoors (during both play and exploration), exposure to the outdoors while on a farm, and structured activities led by non-relative adults.

Using these findings, the scientists developed a detailed, 8-page questionnaire exploring these themes in greater detail. Specifically, the questionnaire asked about the extent to which different activities influenced individuals' conservation ideals; there was also a final open-ended question asking participants to describe what single experience, if any, most influenced their feelings towards land conservation, and why. During the second phase of the survey, the questionnaire was distributed to 84 landowners, 64 of whom responded.

(Children climbing trees--one of many "unstructured outdoor activities" that can have impacts on the conservation mindsets that they will have as adults)

"Individual experiences in nature" was listed as the most important factor, followed by "free play outdoors," "planned outdoor experience" and "parents/guardians." There was a significant difference between the top two influences (individual experience and free play), as well as between the second and third (free play and planned experience). Other options (including, but not limited to, news media, summer camp, historic event, teachers, and 4-H) generally had similar impacts, though friends (6th most important on the list) were found to be significantly more important than news media (7th most important on the list). Answers to the open-ended question aligned with those given elsewhere during both phases of the experiment: Respondents cited things like individual experiences, farm experiences (free play, in particular), growing up in and around nature, and family members and activities.

Overwhelmingly, the results of the study indicate that early life activities are a vital element in the development of pro-environmental behaviors later in life. While similar patterns have previously been found in studies of environmental activists, this is the first study to show that "ordinary" citizens--who do not necessarily make conservation their life's work--are similarly impacted by the events of their childhoods. Particularly interesting was the finding that unstructured and informal childhood experiences are significantly different--and, seemingly, more important--than other types of outdoor activities. This is a pattern that has consistently been found regardless of nationality and geographical location.

These results emphasize the importance of having natural areas available for recreational activities. Given the extent of urbanization and the speed at which it is increasing, the authors express some worry that there could be a cycle of negative feedback reducing conservation activity in the future: Since the majority of the human population now lives in urban areas, many of today's children may not experience much nature during their formative years, causing a reduction in land preservation activity over the next couple decades, leading to even further decreases in natural experiences, and so on. Clearly, it is important to encourage parents to take their children to wilderness areas.

(A structured environmental education program. Though seemingly not as important as free time outside, activities like this do appear to play a role in fostering a conservation mindset.)

One question raised by the current study is how important formalized environmental programs really are. Although they were consistently listed within the top 4 activities influencing conservation attitudes, they always ranked beneath unstructured events such as play and exploration. It will be important to understand the impact of outreach activities and determine whether there are ways to improve their efficacy. Other follow-up research might seek to compare CE landowners and non-CE landowners in order to investigate whether, and which, early life experiences differ between the two groups. In addition to helping parents and educators foster stronger and better relationships between children and nature, an increased understanding of how the conservation mindset is developed will enable managers to better target those individuals who are likely to be most interested in assisting with environmental efforts. This could be particularly important in urban areas, where wilderness habitats, and the opportunities to utilize them, may be few and far between.

Farmer, J.R., Chancellor, C., Fischer, B.C. 2011. Space to romp and roam and how it may promote land conservation. Natural Areas Journal 31(4):340-348.

Thanks to the following websites for providing the images used in this post:

Friday, 18 November 2011

Conservation culture: shaping your feelings towards environmentalism?

What determines how people feel about important conservation issues such as the role and importance of wilderness areas, anthropogenic development, and the use of natural resources? According to conservationist Rebecca Hardin (University of Michigan School of Environment and Natural Resources), writing in Conservation Biology's recent 25th anniversary edition, it is the "conservation culture" to which we have been exposed, and to which we currently belong. She defines "conservation culture" as "a series of distinct aesthetic, technical, and ideological positions." Hardin argues that an awareness of the symbols and meanings in own conservation culture, as well as the others that surround us, is essential for developing practical conservation plans in the future.

If this sounds a bit more philosophical than the standard conservation plan, that's probably because Hardin is not just a conservationist, but also an anthropologist, a political scientist, and, most importantly, an introspective person. In her Conservation Biology essay, Hardin describes a series of contrasts and conflicts that have marked her experiences with nature throughout her life. As a girl in suburban Tennessee, she spent her weekdays in human-modified environments but then escaped into the idyllic Great Smoky Mountains National Park during weekends. "As an adolescent," she writes, "I was vaguely conscious of ways of life that had been displaced in favor of the settlements that matured into today's suburban riverbanks." Impacted groups included rural agrarians and, dating from an even earlier time, Native American tribes. Later, she became more interested in these and other "rural" and "primitive" cultures, but found that preliminary attempts by academics to capture "traditional" people in writing only ended up advancing the stereotype that "suburbia" and "wilderness" are completely distinct entities and attitudes. Hardin felt, however, that these were two extremes on a continuum, and that somewhere in the middle there must be some way for humans to exist in balance--utilizing resources in a sustainable way that preserved some amount of natural habitat.

(The Great Smoky Mountains, as viewed from Mount Le Conte)

The stereotypes that Hardin encountered in these academic texts also permeate popular culture. As examples, Hardin lists Lord of the Rings, Avatar, Erin Brokovitch, and Gasland, in which the villains destroy or poison the wilderness, while the heroes try to preserve and defend it. Likewise, she writes, conservationists also often portray their work in black and white, suggesting that there is no way for humans to coexist with nature without either destroying it or completely leaving it alone. Unfortunately, this leaves little room for reality--the need to farm for food and build structures for homes, or the desire to have access to wilderness areas for recreational purposes. Hardin calls this a "contradictory culture of conservation"--when our ideals pull us in different directions at the same time.

But where do these ideals come from in the first place? Hardin argues that some develop as a result of our own experiences, while others are influenced by social forces--education and religion, for instance. Different messages may come from different sectors, thus causing ideological conflict. Hardin reports feeling this conflict in her own life; she has done extensive conservation work in the field in remote locations, but then admits to thoroughly enjoying the luxuries of the city once she returns from the wild. She posits that many, if not most, people have probably felt similar personal conflicts at one time or another, and that these same conflicts are writ large within conservation institutions. This has been particularly true over the last couple decades, during which the field of conservation has shifted and expanded to make room for a variety of interests, people, techniques, and foci.

(Treebeard, from J.R.R. Tolkien's Lord of the Rings trilogy. Hardin points out that many modern stories feature villains like Saruman the White, who, in Tolkien's story, cuts down trees in order to promote industrial growth; he serves as a symbol of technology and development. He is thwarted by the ents, who, led by Treebeard and accompanied by Pippin and Merry, serve as hero-conservationists by flooding Saruman's domain and allowing nature to reclaim the land.)

One of the difficulties of conservation, Hardin writes, is that it is not about individual heroes--or even, much of the time, about individual villains (though of course, as the Deepwater Horizon scandal has shown, you can occasionally pinpoint a single guilty person or entity). Rather, it is a complex and widespread process that requires compromises between many individuals and organizations, and engagement of all those who are impacted by particular management techniques. Many join the field because of an interest in going outdoors and getting "muddy boots," but are ultimately forced to "[ascend] the administrative ladder from the field to the metropolis" in order to be most effective. This does not necessarily indicate shifting ideals or "selling out," but making personal sacrifices in order to achieve important goals.

Success will also stem from "[having] the intercultural tools to identify competing conservation cultures" in distinct places, yet also "consider links between them." Hardin's description of her native Tennessee provide good examples of these scenarios. Her parents were part of a movement to protect a historical tree at the cost of a historical building; in the ensuing battle between those for and against the project, natural history was pitted against human history. But it is not always the case that different groups of people lobby for different outcomes; right down the road, Appalachians of both European and Cherokee descent--nominally from two different worlds--share the same interest of gaining access to preserved land that they feel is an important part of their heritages. Conservationists will need to be able to evaluate circumstances like these and identify and understand the ways that nature can link disparate peoples, as well as pinpoint instances when wilderness preservation--or lack thereof--can drive a wedge between individuals or groups with uperficially similar goals and interests.

It sounds like a tough challenge, but Hardin suggests that we can start by looking within. There is, she says, a need to "actively [examine] our own desires, beliefs, and consumption practices" in order to "[avoid] outwardly focused cynicism about the organizations around us and [encourage] alternative formulations of future environmental politics." This advice is somewhat of a cross between two time-honored pieces of wisdom: "An unexamined life is not worth living" (Socrates) and "Let he who is without sin cast the first stone" (The King James Bible, John 8:2-11). Hardin points out that self-examination has not traditionally played an important role in mainstream conservation. However, since "grounded reflexivity considers how our own memories, sensations, and cultural symbols structure our actions and preclude some actions," being more in tune with both our own motivations and those of the people around us may eventually lead to greater innovations, improved outreach, and, ultimately, more valuable and effective conservation efforts.

Hardin, Rebecca. 2011. Competing cultures of conservation. Conservation Biology 25(6):1098-1102.

Thanks to the following websites for providing the images used in this post:

Thursday, 17 November 2011

Do urban habitats act as refuges from predators?

There have been many theories proposed to explain why some species do so well in human-disturbed areas. One of these is the "predator refuge hypothesis," which states that urban species thrive because they are released from predation pressures that they would ordinarily face in the wild. This may occur as a result of fewer predators, a different mixture of "strong" predators and those who only occasionally prey on particular species, or a shift in the diets of predators (which, for instance, might begin to prefer easily accessible human food left in dumpsters).

A recent study on northern mockingbirds (Mimus polyglottos) has utilized video cameras in an attempt to validate the predator refuge hypothesis and uncover the mechanisms that might drive it. Mockingbirds are considered to be "urban adaptors"--or, to use the new phrase suggested in the current study, "urban-positive." Previous work has suggested that nest predation rates are lower for this species in urban areas than at rural sites. Researcher Christine Stracey (from the University of Florida and Florida Museum of Natural History) placed video cameras at mockingbird nests across an urban-rural gradient in order to catch predators red-handed and evaluate which species pose the greatest threats to mockingbird breeding success. Further, she assessed whether abundances of these predators varied at urban and rural sites.These data allowed her to assess whether urban mockingbirds were, indeed, at lower risk of predation and, if so, why.

(Northern mockingbird, Mimus polyglottos)

Stracey's study was conducted in and around Gainesville, Florida, where she focused on mockingbirds nesting in 2 parking lots, 3 residential neighborhoods, 2 pastures, and 1 wildlife refuge. After locating active nests, Stracey visited them every 4 days to check whether or not depredation had occurred. This allowed her to calculate survival rates reflecting how likely it was for the nests to escape predation. Over the 3 years of the study, Stracey also placed cameras at a total of 144 nests and successfully recorded 58 predation events. By watching video of the predators in action, Stracey could identify which species were the most common culprits.

When calculating nest survival rates, Stracey investigated the influence of habitat type, nest stage, and date. Interestingly, survival was associated with different factors during each of the 3 years of the study. In 2007, survival was highest in both the laying and nestling stage at later dates in the season; in 2008, eggs survived at a higher rate than nestlings, and survival at both nestling and laying stages decreased throughout the season; in 2009, habitat type was very important, with nests in parking lots surviving better than those in other types of site. Clearly, mockingbird breeding success is determined by a complex interplay of many environmental variables that likely impact both the mockingbirds and the predators, as well as interactions between these two groups of species. However, there was less inter-year variation in urban areas, which may indicate that urban environments provide a constant supply of resources, while non-urban areas experience natural fluctuations from year to year. This flux (or lack thereof) could drive predators to be more or less interested in mockingbird nests as a source of food.

(A Cooper's hawk, Accipiter cooperii. This individual is sitting on a bird feeder--a common activity of small urban hawks, who often treat backyards like buffets.)

The results from the video analysis were a bit more straightforward. Eight different species or species groups were observed preying on active mockingbird nests: domestic cats (Felis cauts), American crows (Corvus brachyrhynchos), swallow-tailed kites (Elanoides forficatus), snakes, Cooper's hawks (Accipiter cooperii), flying squirrels, Virginia opossums (Didelphis virginiana), and raccoons (Procyon lotor). Urban mockingbirds could expect to face similar foes regardless of which residential area they settled in, and non-urban mockingbirds could expect the same predators whether they settled in a pasture or a wildlife reserve. However, there was a significant difference between the urban and non-urban sites. Specifically, domestic cats (Felis catus) were responsible for >70% (17/24) of predation events in urban areas, whereas Cooper's hawks (Accipiter cooperii) did the most damage in non-urban areas (45%, or 15/33 predation events).

Although urban mockingbirds were able to take refuge from particular predators--especially Cooper's Hawks--they were by no means living in a safe urban paradise. The most successful mockingbird predators--cats--were present only in urban areas. On the other hand, the predators that were found only in rural areas (including flying squirrels, raccoons, and opossums) were much less of a threat. Stracey feels that, "on a superficial level," her results indicate some prey switching in urban predators. For instance, she expected to find predation by common urban species such as fish crows (Corvus ossifragus), boat-tailed grackles (Quiscalus major), and common grackles, (Quiscalus quiscula), as well as by the deadly rural predator, the Cooper's hawk. However, in urban locations, these birds may be "distracted" away from mockingbirds by other sources of food.

(A northern mockingbird nest, hidden amongst the branches of a bush.)

It is more difficult to determine what the data have to say about the possibility of "incidental predation," when predators eat mockingbird nests that they happen to encounter while searching for other, preferred, food items. In the residential areas, several cats supplemented their diets with mockingbird chicks even though they were receiving food from humans; on the other hand, there was no evidence that predators had actually been attracted to mockingbird breeding areas by the presence of alternate food. Clearly, more information is needed about the diets of potential mockingbird predators, both within urban and non-urban areas individually, and across the entire rural-urban gradient. Though it may be time-consuming, a longitudinal analysis of what the predators are eating, how much they consume, and where they find it will be useful in understanding the specific role of mockingbird-related foods in their diets.

Another interesting follow-up study might focus on nest defense behaviors. Mockingbirds are known to be fiercely aggressive towards nearly all species that trespass too close to their nests. Here, the two strongest predators were those that were most difficult to deter by mobbing--and, in fact, posed threats not only to chicks but also to the territorial adults. For mockingbirds and other species, the effect of urban predators may be mitigated by the strength of the adults' nest defense display. In order to study this in greater detail, it will be important to focus on species of a variety of sizes and "boldnesses," as well as investigating those that utilize different styles and locations of nest (which may be more or less easily discovered by predators).

 (Northern mockingbird mobbing a red-tailed hawk.)

Despite the new questions raised by this study, it does provide pretty definitive proof of one thing: the deadliness of domestic cats. Because the majority of feline predation events occurred at night, Stracey recommends that cat owners keep their pets indoors overnight in order to minimize predation of wild birds; although this might be useful year-round, she places particular emphasis on the breeding season, when vulnerable eggs and chicks are abundant.

For supplementary images associated with this post, please visit the Anthrophysis pin board at Pinterest.

Stracey, Christine M. 2011. Resolving the urban nest predator paradox: the role of alternative foods for nest predators. Biological Conservation 144:1545-1552.

Thanks to the following websites for providing the images used in this post: