Behavioral Studies (behavioral + studies)

Distribution by Scientific Domains


Selected Abstracts


Development of individually distinct recognition cues

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 7 2006
Jill M. Mateo
Abstract Despite extensive research on the functions of kin recognition, little is known about ontogenetic changes in the cues mediating such recognition. In Belding's ground squirrels, Spermophilus beldingi, secretions from oral glands are both individually distinct and kin distinct, and function in social recognition across many contexts. Behavioral studies of recognition and kin preferences suggest that these cues may change across development, particularly around the time of weaning and emergence from natal burrows (around 25 days of age). I used an habituation-discrimination task with captive S. beldingi, presenting subjects with odors collected from a pair of pups at several ages across early development. I found that at 21 days of age, but not at 7 or 14, young produce detectable odors. Odors are not individually distinct, however, until 28 days of age, after young have emerged from their burrows and begun foraging. In addition, an individual's odor continues to develop after emergence: odors produced by an individual at 20 and 40 days of age are perceived as dissimilar, yet odors produced at 28 and 40 days are treated as similar. Developmental changes in odors provide a proximate explanation for why S. beldingi littermate preferences are not consolidated until after natal emergence, and demonstrate that conspecifics must update their recognition templates as young develop. 2006 Wiley Periodicals, Inc. Dev Psychobiol 48: 508,519, 2006. [source]


Effects of sex chromosome aneuploidy on male sexual behavior

GENES, BRAIN AND BEHAVIOR, Issue 6 2008
J. H. Park
Incidence of sex chromosome aneuploidy in men is as high as 1:500. The predominant conditions are an additional Y chromosome (47,XYY) or an additional X chromosome (47,XXY). Behavioral studies using animal models of these conditions are rare. To assess the role of sex chromosome aneuploidy on sexual behavior, we used mice with a spontaneous mutation on the Y chromosome in which the testis-determining gene Sry is deleted (referred to as Y,) and insertion of a Sry transgene on an autosome. Dams were aneuploid (XXY,) and the sires had an inserted Sry transgene (XYSry). Litters contained six male genotypes, XY, XYY,, XXSry, XXY,Sry, XYSry and XYY,Sry. In order to eliminate possible differences in levels of testosterone, all of the subjects were castrated and received testosterone implants prior to tests for male sex behavior. Mice with an additional copy of the Y, chromosome (XYY,) had shorter latencies to intromit and achieve ejaculations than XY males. In a comparison of the four genotypes bearing the Sry transgene, males with two copies of the X chromosome (XXSry and XXY,Sry) had longer latencies to mount and thrust than males with only one copy of the X chromosome (XYSry and XYY,Sry) and decreased frequencies of mounts and intromissions as compared with XYSry males. The results implicate novel roles for sex chromosome genes in sexual behaviors. [source]


Sexual dimorphism of vocal control nuclei in budgerigars (Melopsittacus undulatus) revealed with Nissl and NADPH-d staining

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2005
Steven E. Brauth
Abstract Nissl staining and nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry were used to explore the existence of sexual dimorphism in vocal control nuclei of adult budgerigars (Melopsittacus undulatus), a parrot species capable of lifelong vocal learning. Behavioral studies indicate that adult males possess larger vocal repertoires than adult females and learn new calls more quickly. The results of the present study show that the volumes of all vocal nuclei, as measured using both Nissl-stained and NADPH-d-stained material, as well as the total numbers of NADPH-d neurons, were 35,110% greater in males. Furthermore, all vocal nuclei exhibit conspicuous NADPH-d staining compared to surrounding fields in both adult males and females. Nevertheless, there were no significant gender differences in either the intensity of neuropil staining or the densities of NADPH-d neurons in vocal nuclei. Moreover NADPH-d neuron somal shapes were similar in males and females. Diameters of NADPH-d neurons in vocal nuclei were 8.5,32% larger in males than in females. Greater size of NADPH-d neuronal somata in males may be a general property of this cell type in budgerigars because a similar gender difference was found in a visual nucleus, the entopallium, which is not directly associated with the vocal control system and does not exhibit sexual dimorphism in total volume or total NADPH-d neuron numbers. Taken together, the results of the present study favor the hypothesis that superior lifelong vocal learning ability in male budgerigars rests largely on larger volumes of vocal control nuclei in males rather than on sexual dimorphism in the internal composition of vocal nuclei. J. Comp. Neurol. 484:15,27, 2005. 2005 Wiley-Liss, Inc. [source]


The neurobiological profile of girls with ADHD

DEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 4 2008
E. Mark Mahone
Abstract Since boys are more commonly diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) than girls, the majority of theories and published research studies of ADHD have been based on samples comprised primarily (or exclusively) of boys. While psychosocial impairment in girls with ADHD is well established, the neuropsychological and neurobiological basis of these deficits is less consistently observed. There is growing evidence that boys' and girls' brains develop and mature at different rates, suggesting that the trajectory of early anomalous brain development in ADHD may also be sex-specific. It remains unclear, however, whether earlier brain maturation observed in girls with ADHD is protective. In this review, we outline the current theory and research findings that seek to establish a unique neurobiological profile of girls with ADHD, highlighting sex differences in typical brain development and among children with ADHD. The review highlights findings from neurological, neurocognitive, and behavioral studies. Future research directions are suggested, including the need for longitudinal neuroimaging and neurobehavioral investigation beginning as early as the preschool years, and continuing through adolescence and adulthood, with consideration of identified sex differences in the development of ADHD. 2008 Wiley-Liss, Inc. Dev Disabil Res Rev 2008;14:276,284. [source]


The neuroanatomy and neuroendocrinology of fragile X syndrome

DEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 1 2004
David Hessl
Abstract Fragile X syndrome (FXS), caused by a single gene mutation on the X chromosome, offers a unique opportunity for investigation of gene,brain,behavior relationships. Recent advances in molecular genetics, human brain imaging, and behavioral studies have started to unravel the complex pathways leading to the cognitive, psychiatric, and physical features that are unique to this syndrome. In this article, we summarize studies focused on the neuroanatomy and neuroendocrinology of FXS. A review of structural imaging studies of individuals with the full mutation shows that several brain regions are enlarged, including the hippocampus, amygdala, caudate nucleus, and thalamus, even after controlling for overall brain volume. These regions mediate several cognitive and behavioral functions known to be aberrant in FXS such as memory and learning, information and sensory processing, and social and emotional behavior. Two regions, the cerebellar vermis, important for a variety of cognitive tasks and regulation of motor behavior, and the superior temporal gyrus, involved in processing complex auditory stimuli, are reported to be reduced in size relative to controls. Functional imaging, typically limited to females, has emphasized that individuals with FXS do not adequately recruit brain regions that are normally utilized by unaffected individuals to carry out various cognitive tasks, such as arithmetic processing or visual memory tasks. Finally, we review a number of neuroendocrine studies implicating hypothalamic dysfunction in FXS, including abnormal activation of the hypothalamic,pituitary,adrenal (HPA) axis. These studies may help to explain the abnormal stress responses, sleep abnormalities, and physical growth patterns commonly seen in affected individuals. In the future, innovative longitudinal studies to investigate development of neurobiologic and behavioral features over time, and ultimately empirical testing of pharmacological, behavioral, and even molecular genetic interventions using MRI are likely to yield significant positive changes in the lives of persons with FXS, as well as increase our understanding of the development of psychiatric and learning problems in the general population. MRDD Research Reviews 2004;10:17,24. 2004 Wiley-Liss, Inc. [source]


The microstructure of ethanol drinking: genetic and behavioral factors in the control of drinking patterns

ADDICTION, Issue 8s2 2000
Herman H. Samson
The concept of craving can be examined in many different ways, depending upon the individual definition of the term. Using the concepts and procedures of regulatory behavior analysis, this review explores behavioral studies in rats that have some relationships to some of the possible processes that underlie the concept of craving in humans. Data are reviewed from studies employing both limited and continuous access to ethanol, examining the role of access availability, ethanol initiation, response cost, time since last access, composition of the ethanol containing solution and genetic selection. From this review, it is clear that rat models can implicate important variables involved in the control of human alcohol consumption. [source]


Semantic confusion regarding the development of multisensory integration: a practical solution

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2010
Barry E. Stein
Abstract There is now a good deal of data from neurophysiological studies in animals and behavioral studies in human infants regarding the development of multisensory processing capabilities. Although the conclusions drawn from these different datasets sometimes appear to conflict, many of the differences are due to the use of different terms to mean the same thing and, more problematic, the use of similar terms to mean different things. Semantic issues are pervasive in the field and complicate communication among groups using different methods to study similar issues. Achieving clarity of communication among different investigative groups is essential for each to make full use of the findings of others, and an important step in this direction is to identify areas of semantic confusion. In this way investigators can be encouraged to use terms whose meaning and underlying assumptions are unambiguous because they are commonly accepted. Although this issue is of obvious importance to the large and very rapidly growing number of researchers working on multisensory processes, it is perhaps even more important to the non-cognoscenti. Those who wish to benefit from the scholarship in this field but are unfamiliar with the issues identified here are most likely to be confused by semantic inconsistencies. The current discussion attempts to document some of the more problematic of these, begin a discussion about the nature of the confusion and suggest some possible solutions. [source]


Vasopressin modulates lateral septal network activity via two distinct electrophysiological mechanisms

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2007
G. Allaman-Exertier
Abstract The lateral septal area is rich in vasopressin V1A receptors and is densely innervated by vasopressinergic axons, originating mainly from the bed nucleus of the stria terminalis and the amygdala. Genetic and behavioral studies provide evidence that activation of vasopressin receptors in this area plays a determinant role in promoting social recognition. What could be the neuronal mechanism underlying this effect? Using rat brain slices and whole-cell recordings, we found that lateral septal neurons are under the influence of a basal GABAergic inhibitory input. Vasopressin, acting via V1A but not V1B receptors, greatly enhanced this input in nearly all neurons. The peptide had no effect on miniature inhibitory postsynaptic currents, indicating that it acted on receptors located in the somatodendritic membrane, rather than on axon terminals, of GABAergic interneurons. Cell-attached recordings showed that vasopressin can cause a direct excitation of a subpopulation of lateral septal neurons by acting via V1A but not V1B receptors. The presence in the lateral septum of V1A but not of V1B receptors was confirmed by competition binding studies using light microscopic autoradiography. In conclusion, vasopressin appears to act in the lateral septum in a dual mode: (i) by causing a direct excitation of a subpopulation of neurons, and (ii) by causing an indirect inhibition of virtually all lateral septal neurons. This modulation by vasopressin of the lateral septal circuitry may be part of the neuronal mechanism by which the peptide, acting via V1A receptors, promotes social recognition. [source]


A novel transverse push,pull microprobe: in vitro characterization and in vivo demonstration of the enzymatic production of adenosine in the spinal cord dorsal horn

JOURNAL OF NEUROCHEMISTRY, Issue 1 2001
Shawnna L. Patterson
Adenosine produces analgesia in the spinal cord and can be formed extracellularly through enzymatic conversion of adenine nucleotides. A transverse push,pull microprobe was developed and characterized to sample extracellular adenosine concentrations of the dorsal horn of the rat spinal cord. Samples collected via this sampling technique reveal that AMP is converted to adenosine in the dorsal horn. This conversion is decreased by the ecto-5,-nucleotidase inhibitor, ,,,-methylene ADP. Related behavioral studies demonstrate that AMP administered directly to the spinal cord can reverse the secondary mechanical hyperalgesia characteristic of the intradermal capsaicin model of inflammatory pain. The specific adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dimethylxanthine (CPT) inhibits the antihyperalgesia produced by AMP. This research introduces a novel microprobe that can be used as an adjunct sampling technique to microdialysis and push,pull cannulas. Furthermore, we conclude that AMP is converted to adenosine in the dorsal horn of the spinal cord by ecto-5,-nucleotidase and subsequently may be one source of adenosine, acting through adenosine A1 receptors in the dorsal horn of the spinal cord, which produce antihyperalgesia. [source]


Environmental enrichment stimulates progenitor cell proliferation in the amygdala

JOURNAL OF NEUROSCIENCE RESEARCH, Issue 16 2009
Hiroaki Okuda
Abstract Enriched environments enhance hippocampal neurogenesis, synaptic efficacy, and learning and memory functions. Recent studies have demonstrated that enriched environments can restore learning behavior and long-term memory after significant brain atrophy and neural loss. Emotional and anxiety-related behaviors were also improved by enriched stimuli, but the effect of enriched environments on the amygdala, one of the major emotion-related structures in the central nervous system, remains largely unknown. In this study, we have focused on the effects of an enriched environment on cell proliferation and differentiation in the murine amygdala. The enriched environment increased bromodeoxyuridine (BrdU)-positive (newborn) cell numbers in the amygdala, almost all of which, immediately after a 1-week period of enrichment, expressed the oligodendrocyte progenitor marker Olig2. Furthermore, enriched stimuli significantly suppressed cell death in the amygdala. Some of the BrdU-positive cells in mice exposed to the enriched environment, but none in animals housed in the standard environment, later differentiated into astrocytes. Our findings, taken together with previous behavioral studies, suggest that progenitor proliferation and differentiation in the amygdala may contribute to the beneficial aspects of environmental enrichment such as anxiolytic effects. 2009 Wiley-Liss, Inc. [source]


Effects of Prenatal Alcohol Exposure on Brain Activation During an Arithmetic Task: An fMRI Study

ALCOHOLISM, Issue 11 2009
Priya Santhanam
Background:, While behavioral studies have established that prenatal alcohol exposure (PAE) can result in diminished arithmetic processing capability, the underlying neural correlates of this deficit are still unclear. The aim of the present study was to use functional magnetic resonance imaging to determine the effect of PAE on neuronal activation during a subtraction task. Methods:, Participants were young adults from a low socio-economic status population who were identified prenatally; the sample consisted of healthy unexposed controls (n = 17) and PAE who were subdivided based on the presence (n = 19) or absence of physical dysmorphic signs (n = 18). Multiple regression analysis was used to determine extent of activation and percent signal change during arithmetic processing, using a letter-matching task as the baseline. Region of interest analysis of activation was performed in the native space and normalized for each individual to compensate for the considerable variability in head size observed in the alcohol-exposed population. Results:, An exposure-dependent response was observed in task performance and neuronal activation. Dysmorphic PAE individuals showed significantly lower task-related performance and activation in regions known to be associated with arithmetic processing, including left superior and right inferior parietal regions and medial frontal gyrus, while the nondysmorphic PAE group was generally intermediate but not significantly different from the control group in task performance and activation. Conclusions:, Results indicate that there is a range of effects of PAE on arithmetic processing and that the severity of this deficit may be dependent on degree of impairment demonstrated by the exposed individual. Evidence of physical dysmorphia may be indicative of functional damage to regions associated with arithmetic calculation, resulting in markedly impaired neuronal recruitment. [source]


Effective Methods to Improve Recruitment and Retention in School-Based Substance Use Prevention Studies

JOURNAL OF SCHOOL HEALTH, Issue 9 2009
Jean-Marie Bruzzese PhD
ABSTRACT BACKGROUND: Poor recruitment and high attrition may invalidate results of research studies. This paper describes successful recruitment and retention strategies in a school-based substance use prevention trial and explores factors associated with intervention attendance and retention. METHODS: A total of 384 parent-child dyads from 15 schools in the New York Metropolitan area participated in a control trial, testing the efficacy of parent-training to prevent youth substance use. Assessments were completed immediately post-intervention and 6-, 12-, and 24-month postintervention. Logistic regression analyses were used to determine which familial and study characteristics predicted attendance in the intervention and retention by parents and youth. RESULTS: 84% of intervention parents attended 4 of the 5 workshops; 83% of control parents attended their single workshop. Intervention attendance was predicted by parent job status, but this was not significant after controlling for other family factors. Retention rates ranged from 87% to 91% over the 2 years. No family characteristics predicted retention, but time since baseline and attendance at treatment workshops and the control workshop did. For children, age at baseline and ethnicity predicted retention, but this did not remain significant in the adjusted model. CONCLUSION: Intervention attendance was high and retention rates far exceeded the minimum standard of 70% retention in behavioral studies. Recruitment and retention strategies were effective for different family constellations. Efforts to maximize participation in both treatment and control interventions are critical to retention in longitudinal trials. [source]


Highlights of Programmatic, Interdisciplinary Research on Writing

LEARNING DISABILITIES RESEARCH & PRACTICE, Issue 2 2009
Virginia W. Berninger
An overview of research topics and findings from an interdisciplinary, programmatic line of research on writing over the past 25 years is presented. The cross-sectional assessment studies (grades 1 to 9) showed which measures uniquely explained variance in handwriting, spelling, and composing and thus validated their use in assessment. These and the longitudinal studies (grades 1 to 5 and 3 to 7) contributed to knowledge of the cognitive processes of writing, within a working memory architecture that orchestrates multiple component processes in time to achieve specific writing goals, especially the translation of ideas into words, syntax, and text, and transcription (handwriting and spelling) by pen and by keyboard. Combined brain imaging and behavioral studies of writing have provided converging evidence for brain,behavior relationships for handwriting, spelling, and composing and for the role of temporally coordinated working memory, including an orthographic loop with a graphic-motor envelope for word production. A series of instructional studies for at-risk writers, which was taught to all levels of language to overcome working memory inefficiencies, were organized according to the developmental steppingstones in writing acquisition and show that writing problems can be prevented. Other studies with older, struggling writers validated effective instructional approaches for helping struggling writers become reading-writers who integrate both written language skills in literacy learning. [source]


Mirror Neurons, the Motor System and Language: From the Motor Theory to Embodied Cognition and Beyond

LINGUISTICS & LANGUAGE COMPASS (ELECTRONIC), Issue 6 2009
Jonathan H. Venezia
The motor theory of speech perception states that phonetic segments in the acoustic speech stream activate stored motor commands in the brain that give rise to perception of discrete speech sounds. The motor theory fell out of favor when growing evidence from lesion and behavioral studies led aspects of the theory to appear untenable. However, with the recent discovery of mirror neurons and their potential role in action understanding, interest in the motor theory of speech perception is renewed. We review the function and properties of mirror neurons in monkeys, and briefly describe the current literature that focuses on the role of a putative human mirror system in cognition and language processing. Further, we describe proposed evidence for the involvement of the motor system in perceptive speech processing, and point out ambiguities in the literature that arise from the tight coupling of sensory and motor processes in speech comprehension. An alternative theory proposing that sensory representations in superior temporal cortex are mapped onto frontal production networks is offered. We cite evidence that confirms the failure of the motor theory to accurately describe perceptive processes in speech, and promote the conclusion that speech representations are fundamentally sensory in nature. [source]


Sensory functions in dystonia: Insights from behavioral studies,,

MOVEMENT DISORDERS, Issue 10 2009
Michele Tinazzi MD
Abstract The pathophysiology of primary dystonia is thought to involve dysfunction of the basal ganglia cortico-striatal-thalamo-cortical motor circuits. In the past, emphasis was placed on the role of the basal ganglia in controlling movements; in more recent times, however, it has also become clear that they play an important part in sensory as well as cognitive functions. Here, we review evidence for dysfunction of sensory processing in patients with dystonia, and speculate that this may lead to abnormalities in a crucial role of the basal ganglia that links sensory information to appropriate motor output. Sensory function, particularly in the somatosensory domain, has been shown to be compromised in patients with primary dystonia, both in adult onset focal dystonia and in genetically characterized DYT1 dystonia. Given that nonaffected DYT1 gene carriers may show similar abnormalities to clinically affected individuals, sensory deficits could constitute a subclinical endophenotypic trait of disease that precedes overt clinical manifestations. Whether they can trigger primary dystonia or are an epiphenomenon is an issue warranting further study, but the fact that a number of different neurorehabilitative approaches explicitly manipulate somatosensory inputs to improve motor function suggests there may be a causal link between them. We believe that in future, randomized, blind and controlled studies in large patient populations should address this issue, providing efficient strategies to aid functional recovery, particularly in focal hand dystonia, where the available medical treatments offer little benefit. 2009 Movement Disorder Society [source]


Brief communication: Locomotor limb preferences in captive chimpanzees (Pan troglodytes): Implications for morphological asymmetries in limb bones

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2008
William D. Hopkins
Abstract Understanding the evolutionary origins of hemispheric specialization remains a topic of considerable interest in a variety of scientific disciplines. Whether nonhuman primates exhibit population-level limb preferences continues to be a controversial topic. In this study, limb preferences for ascending and descending locomotion were assessed as a means of examining the hypothesis that asymmetries in forelimb bones might be attributed to asymmetries in posture. The results indicated that captive chimpanzees showed a population-level leftward asymmetry in descending locomotion but no group bias for ascending locomotion. The results are consistent with previous behavioral studies in captive chimpanzees as well as studies on skeletal asymmetries of the forelimbs of chimpanzees. Am J Phys Anthropol, 2008. 2008 Wiley-Liss, Inc. [source]


Sex, age, and family differences in the chemical composition of owl monkey (Aotus nancymaae) subcaudal scent secretions

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2008
Edith A. MacDonald
Abstract Numerous behavioral studies have shown that animals use olfactory cues as inbreeding avoidance or kin avoidance mechanisms, implying that scent is unique to families. However, few studies have analyzed the chemical profile of a scent and ascertained the messages that are conveyed in scent secretions. Owl monkeys (Aotus nancymaae) are socially monogamous primates that utilize scent when interacting with foreign conspecifics. This suggests there is a difference in the chemical composition of scent marks. We chemically analyzed sub-caudal gland samples from three families of captive owl monkeys (Aotus nancymaae). Samples were analyzed by capillary GC-MS and relative retention time and fragment pattern was compared with known standards. Gland samples were high in large plant-based shikikate metabolites and fatty ketones; alcohols, acids, and acetates were virtually absent. Gender, age, and family could be reliably classified using discriminant analysis (92.9, 100, and 100%, respectively). Female scent profiles were greater in concentration of aromatic plant metabolites, possibly the result of a different diet or physiological differences in female metabolism as compared to male. Offspring of adult age still living in their natal group showed a less complex chemical profile than their parents. Finally, each family had its own unique and complex chemical profile. The presence of family scent may play a role in mediating social interactions. Am. J. Primatol. 70:12,18, 2007. 2007 Wiley-Liss, Inc. [source]


The complete genome sequence of a dog: a perspective

BIOESSAYS, Issue 6 2006
Soohyun Lee
A complete, high-quality reference sequence of a dog genome was recently produced by a team of researchers led by the Broad Institute, achieving another major milestone in deciphering the genomic landscape of mammalian organisms. The genome sequence provides an indispensable resource for comparative analysis and novel insights into dog and human evolution and history. Together with the survey sequence of a poodle previously published in 2003, the two dog genome sequences allowed identification of more than 2.5 million single nucleotide polymorphisms within and between dog breeds, which can be used in evolutionary analysis, behavioral studies and disease gene mapping.1 2005 Wiley Periodicals, Inc. BioEssays 28: 569,573, 2006. 2006 Wiley Periodicals, Inc. [source]


Diversity of Interactions: A Metric for Studies of Biodiversity

BIOTROPICA, Issue 3 2010
Lee A. Dyer
ABSTRACT Multitrophic interactions play key roles in the origin and maintenance of species diversity, and the study of these interactions has contributed to important theoretical advances in ecology and evolutionary biology. Nevertheless, most biodiversity inventories focus on static species lists, and prominent theories of diversity still ignore trophic interactions. The lack of a simple interaction metric that is analogous to species richness is one reason why diversity of interactions is not examined as a response or predictor variable in diversity studies. Using plant,herbivore,enemy trophic chains as an example, we develop a simple metric of diversity in which richness, diversity indices (e.g., Simpson's 1/D), and rarefaction diversity are calculated with links as the basic unit rather than species. Interactions include all two-link (herbivore,plant and enemy,herbivore) and three-link (enemy,herbivore,plant) chains found in a study unit. This metric is different from other indices, such as traditional diversity measures, connectivity and interaction diversity in food-web studies, and the diversity of interaction index in behavioral studies, and it is easier to compute. Using this approach to studying diversity provides novel insight into debates about neutrality and correlations between diversity, stability, productivity, and ecosystem services. Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp [source]