Effects of Native and Non-Native Grassland Plant Communities on Breeding Passerine Birds: Implications for Restoration of Northwest Bunchgrass Prairie

One common problem encountered when restoring grasslands is the prominence of non-native plant species. It is unclear what effect non-native plants have on habitat quality of grassland passerines, which are among the most imperiled groups of birds. In 2004 and 2005, we compared patterns of avian reproduction and the mechanisms that might influence those patterns across a gradient of 13 grasslands in the Zumwalt Prairie in northeastern Oregon that vary in the degree of non-native plant cover (0.9–53.4%). We monitored the fate of 201 nests of all the breeding species in these pastures and found no association of percent non-native cover with nest densities, clutch size, productivity, nest survival, and nestling size. Regardless of the degree of non-native cover, birds primarily fed on Coleoptera, Orthoptera, and Araneae. But as percent non-native cover in the pastures increased, Orthoptera made up a greater proportion of diet and Coleoptera made up a smaller proportion. These diet switches were not the result of changes in terrestrial invertebrate abundance but may be related to decreases in percent bare ground associated with increasing cover of non-native vegetation. Measures of nest crypticity were not associated with cover of non-native vegetation, suggesting that predation risk may not increase with increased cover of non-native vegetation. Thus, the study results show that increased non-native cover is not associated with reduced food supplies or increased predation risk for nesting birds, supporting the growing body of evidence that grasslands with a mix of native and non-native vegetation can provide suitable habitat for native grassland breeding birds.     

Beyond the phenotypic gambit: molecular behavioural ecology and the evolution of genetic architecture

Most studies of behaviour examine traits whose proximate causes include sensory input and neural decision-making, but conflict and collaboration in biological systems began long before brains or sensory systems evolved. Many behaviours result from non-neural mechanisms such as direct physical contact between recognition proteins or modifications of development that coincide with altered behaviour. These simple molecular mechanisms form the basis of important biological functions and can enact organismal interactions that are as subtle, strategic and interesting as any. The genetic changes that underlie divergent molecular behaviours are often targets of selection, indicating that their functional variation has important fitness consequences. These behaviours evolve by discrete units of quantifiable phenotypic effect (amino acid and regulatory mutations, often by successive mutations of the same gene), so the role of selection in shaping evolutionary change can be evaluated on the scale at which heritable phenotypic variation originates. We describe experimental strategies for finding genes that underlie biochemical and developmental alterations of behaviour, survey the existing literature highlighting cases where the simplicity of molecular behaviours has allowed insight to the evolutionary process and discuss the utility of a genetic knowledge of the sources and spectrum of phenotypic variation for a deeper understanding of how genetic and phenotypic architectures evolve.     

African DNA Lineages in the Mitochondrial Gene Pool of Europeans

Mitochondrial DNA (mtDNA) nucleotide sequences of African origin are found in various European populations at a low frequency (on average, less than 1%). Data on mtDNA variation in Eurasian and African populations have been analyzed, and African mtDNA lineages have been found in Europeans. It has been demonstrated that, despite the high diversity of mtDNA haplotypes of African origin in Europeans, few monophyletic clusters of African lineages are characterized by long-term diversity formed in Europe. Only two such mtDNA clusters (from haplogroups L1b and L3b) have been found, their evolutionary age not exceeding 6500 years. European and African populations have been compared with respect to the frequency distributions of the alleles of autosomal microsatellite loci found in Russian carriers of African mtDNA haplotypes. It has been demonstrated that alleles typical of Europeans are characteristic of the autosomal genotypes of these Russian individuals.     

Local Adaptation and Effects of Grazing among Seedlings of Two Native California Bunchgrass Species: Implications for Restoration

Adaptation to environmental factors may influence the germination and establishment of focal species in ecological restoration. Reciprocal transplants remain one of the best methods to detect local adaptation, but long‐term studies are often not feasible. We conducted reciprocal transplants of the native California bunchgrasses Elymus glaucus and Bromus carinatus between two central California locations to seek evidence of adaptation to local environmental conditions in a single growing season. Experimental plots at one location included grazed and ungrazed sites. The combination of locations and grazing treatments allowed us to determine whether the ability to detect evidence for adaptation depended on grazing regime. In addition, we measured the direct effects of grazing on seedling growth and survival concurrent with our investigation of local adaptation. We detected a homesite advantage for seedling growth or survival in both species, but the factors contributing to adaptive differentiation were species specific. Evidence of local adaptation was detected for seedling biomass in Bromus and for survivorship in Elymus. The homesite advantage observed in both species was greatly reduced under grazed conditions and in Elymus was significant only in the ungrazed plots. Climate and soil analyses detected significant differences between locations in five soil attributes and two climate variables. In particular, differences in exchangeable magnesium indicated that one of the two transplant locations consisted of serpentine soil, which is widely known to drive adaptation in plant populations. Together, these results suggest that it is possible to investigate the scale and factors involved in local adaptation with short‐term transplant studies.     

Persons Versus Brains: Biological Intelligence in Human Organisms

I go deep into the biology of the human organism to argue that the psychological features and functions of persons are realized by cellular and molecular parallel distributed processing networks dispersed throughout the whole body. Persons supervene on the computational processes of nervous, endocrine, immune, and genetic networks. Persons do not go with brains.     

Defenders of the Truth: The Battle for Science in the Sociobiology Debate and Beyond

Defenders of the Truth: The Battle for Science in the Sociobiology Debate and Beyond. Ullica Segerstrile. New York: Oxford University Press, 2000.493 pp.     

The Semiglades: The Collision of Restoration,Social Values,and the Ecosystem Concept

Defining success targets in restoration and how social values affect them are two commonly discussed issues in restoration today. We believe that how success is commonly defined—with vague terms such as “healthy ecosystem” or cited as a return to a previous, historic state—needs to be reevaluated. With the increasing number of novel ecosystems, there is an increasing conflict between the ecosystem concept, social values, and restoration. This arises from the fact that ecosystems are defined by the values of the scientists describing them, necessarily constraining the ecosystem to a generally static concept. It is not directly the concept, but how it is perceived through our filter of social values that represses the creativity and innovation needed in restoration today. Within restoration, we feel that the ecosystem concept does a disservice by ignoring the increasing number of novel systems, and that hinders real progress in a time when hesitation can be costly. To best illustrate this, we offer the example of restoration of the Florida Everglades and how it has become a novel system in pattern and process. We suggest renaming the Everglades “The Semiglades” in hopes of opening a dialog to expose social/ecosystem biases and include novel landscapes in management and planning.     

Restoration of California Native Grasses and Clovers: The Roles of Clipping,Broadleaf Herbicide,and Native Grass Density

One of the major challenges confronting grassland restoration of highly invaded communities is increasing the diversity of native species. There is surprisingly little research investigating how reconstructed native grasslands respond to common management techniques and how these techniques influence the relative establishment of both native grasses and forbs. Despite the diversity and wide distribution of native clovers in California, few practitioners incorporate them into grassland restoration plans. Conversely, non‐native clovers have been seeded extensively onto California rangelands. This study addresses the following questions: (1) Using readily available management tools, is there a strategy that can benefit the growth of both planted native bunchgrasses and seeded clovers? (2) Do native bunchgrasses compete with establishing clovers and non‐native grasses? (3) Do native and non‐native clovers differ in their response to management treatments or in their productivity? Plots were established to test three factors in different combinations over 3 years: (1) early spring clipping, (2) initial broadleaf herbicide, and (3) native bunchgrass planting density. Native and non‐native clovers were seeded in years 2 and 3. Early spring clipping did not have a significant effect on native bunchgrass cover, yet it did result in greater growth of native and non‐native clovers. The direction of the response to broadleaf herbicide changed between years for native bunchgrasses and was consistently negative for native clovers. Plots with higher native grass densities did not adversely affect the seeded clovers, yet non‐native grass cover was reduced. Native and non‐native clovers exhibited similar responses to clipping and established at similar densities.     

Invasion by Non-Native Annual Grasses: The Importance of Species Biomass, Composition, and Time Among California Native Grasses of the Central Valley

The Central Valley of California is noted for its dearth of remnant native grass populations and for low native grass seedling establishment within grasslands now dominated by non‐native annual species. In contrast, remnant populations are common along the coast, and studies have shown an ability for seedlings and adults to compete with non‐native annual grasses. The invasibility of well‐established populations of native grasses in the Central Valley remains unclear. The objectives of this study were to compare the invasibility of native grasses differing in density and species composition and, given the species in this study, to assess the ability of mixes with greater species richness to resist invasion relative to their abilities in monoculture. In the Sacramento Valley of California, six species of native grasses were planted at three densities in monospecific and mixed‐species plots. Percent cover of native perennial and non‐native annual grasses was measured in years 2 and 3, and biomass was sampled in year 5. Native grass biomass and, to a lesser extent, species composition were important in explaining variation in non‐native grass invasibility in the fifth year. Species‐rich treatments did not experience less invasion than would be expected by the proportional invasibility of each species in monoculture. However, invasibility of plots consisting of slower growing, shorter statured species decreased over time, suggesting a successional benefit to diverse communities. This study demonstrates that established stands of native grasses in the Sacramento Valley can resist invasion by non‐native annual grasses and that stand biomass is a particularly important factor in determining invasibility.     

Refocusing the Neurocognitive Approach to Dreams: A Critique of the Hobson Versus Solms Debate.

This article examines the ongoing debate between activation-synthesis theorist J. Allan Hobson and psychoanalytic theorist Mark Solms about the nature of dreaming and dream content. After discussing their neurophysiological disagreements, it argues that they are more similar than different in some important ways, especially in talking about dreams in the same breath as psychosis and in drawing conclusions about dream content on the basis of their neurophysiological assumptions, without any reference to the systematic findings on the issue. Evidence from inside and outside the sleep laboratory on the coherent nature of most dreams is presented to demonstrate that neither theorist is on solid ground in his main assertions. Dreaming is usually a far more realistic and understandable enactment of interests and concerns than the 2 researchers assume. In addition, several of Hobson's and Solms's claims concerning the neural basis of dreaming are challenged on the basis of neurophysiological evidence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estuarine and Tidal Wetland Restoration in the United Kingdom: Policy Versus Practice

Restoration of reclaimed marshes in the United Kingdom, referred to as managed realignment, is both a scientific and a political issue. A cross‐party House of Commons report to Government stressed that provision of long‐term sustainable coastal defenses must start with the premise that “coasts need space” and that government must work to increase public awareness, scientific knowledge, and political will to facilitate such a retreat from the almost sacrosanct existing shoreline. Government, in turn, has agreed with the basis of the report but is aware of conflicting interests, not least the European legislation, which has designated large areas of reclaimed marshes as Special Areas of Conservation that cannot legally be restored to their former tidal processes. Against this background, it is essential that scientific research provides convincing arguments for the necessity for managed realignment, the location, extent, and type of marshlands that need to be restored to provide sustainable flood defenses, maintain and enhance conservation status, and ensure a healthy functioning estuarine system. We examine the political and scientific issues involved, discuss model predictions and field experiments into realignment techniques, and outline the preliminary results of such experiments showing the evolution of restored intertidal wetlands in the United Kingdom.     

Genetic Genealogy: The Woodson Family's Experience

In 1998, Foster and colleagues published the results of a genetic study intended to test whether Thomas Jefferson could have fathered any of Sally Hemings' children. They found that the Jefferson Y chromosome haplotype matched that of a descendant of Hemings' youngest child, but not that of the descendants of the eldest son, Thomas Woodson. The Woodson descendants were shocked by the study's finding, which disagreed with their family oral history. They were suspicious of the study conclusions because of the methods used in recruiting participants for the study and the manner in which they learned of the results. The Woodsons' experience as participants in one of the first examples of genetic genealogy illustrates several issues that both geneticists and amateur genetic genealogists will face in studies of this kind. Misperceptions about the relationship between biology and race, and group genetics in general, can make the interpretation of genetic data difficult. Continuing collaborations between the media and the scientific community will help the public to better understand the risks as well as the benefits of genetic genealogy. Researchers must decide prior to beginning their research what role the human subjects will play in the study and when they will be notified of the study's conclusions. Amateur genetic genealogists should anticipate unexpected outcomes, such as the identification of nonpaternity, to minimize any harmful effects to study participants. Although modern genetic methods provide a powerful new tool for genealogical study, they cannot resolve all genealogical issues, as this study shows, and can involve unanticipated risks to the participants.     

Isolation by distance within a river system: genetic population structuring of Atlantic salmon, Salmo salar, in tributaries of the Varzuga River in northwest Russia

An important issue for designing any conservation programme aimed at preserving genetic diversity is estimation of the scale at which genetic structuring occurs. Additional relevant factors include distinguishing whether or not population structuring is expected to be stable as predicted by the member-vagrant hypothesis, or alternatively, whether populations are more prone to local extinction-recolonization processes, as predicted by the metapopulation evolutionary model. In this study, the population genetic structure of Atlantic salmon from 11 locations within or nearby the Varzuga River tributary system was assessed using 17 microsatellites. Mantel tests and spatial autocorrelation analyses revealed a significant isolation-by-distance signal within the tributary system as well as a negative association between the level of genetic diversity and waterway distance from the river mouth, indicating that dispersal is less likely to occur to populations deep in the tributary system. Individual-level spatial autocorrelation analyses indicated that the majority of migration occurred between populations situated within 20 km of each other. The relatively high level of genetic structuring and significant isolation-by-distance signal observed in the Varzuga tributaries are concordant with the predictions of the member-vagrant evolutionary model. However, one subpopulation in particular revealed signs of instability which may be due to its location in the tidal zone, or due to the fact that it is more affected by human impacts. The results suggest that preservation of a number of spawning sites spaced throughout the tributary system is recommendable for ensuring sustainable fishing tourism in the river.     

The population ecology of contemporary adaptations: what empirical studies reveal about the conditions that promote adaptive evolution

Genetica - Under what conditions might organisms be capable of rapid adaptive evolution? We reviewed published studies documenting contemporary adaptations in natural populations and looked for...     

The seabird paradox: dispersal, genetic structure and population dynamics in a highly mobile, but philopatric albatross species

The philopatric behaviour of albatrosses has intrigued biologists due to the high mobility of these seabirds. It is unknown how albatrosses maintain a system of fragmented populations without frequent dispersal movements, in spite of the long-term temporal heterogeneity in resource distribution at sea. We used both genetic (amplified fragment length polymorphism) and capture-mark-recapture (CMR) data to identify explicitly which among several models of population dynamics best applies to the wandering albatross (Diomedea exulans) and to test for migration-drift equilibrium. We previously documented an extremely low genetic diversity in this species. Here, we show that populations exhibit little genetic differentiation across the species' range (Theta(B) < 0.05, where Theta(B) is an F(ST) analogue). Furthermore, there was no evidence of hierarchical structure or isolation-by-distance. Wright's F(ST) between pairs of colonies were low in general and the pattern was consistent with a nonequilibrium genetic model. In contrast, CMR data collected over the last decades indicated that about one bird per cohort has dispersed among islands. Overall, F(ST) values were not indicative of contemporary dispersal as inferred from CMR data. Moreover, all genotypes grouped together in a cluster analysis, indicating that current colonies may have derived from one ancestral source that had a low genetic diversity. A metapopulation dynamics model including a recent (postglacial) colonization of several islands seems consistent with both the very low levels of genetic diversity and structure within the wandering albatross. Yet, our data suggest that several other factors including ongoing gene flow, recurrent long-distance dispersal and source-sink dynamics have contributed to different extent in shaping the genetic signature observed in this species. Our results show that an absence of genetic structuring may in itself reveal little about the true population dynamics in seabirds, but can provide insights into important processes when a comparison with other information, such as demographic data, is possible.     

The Biology of Invasions: The Genetic Adaptation Paradox

One of the most relevant topics in the biology of invasion concerns the genetic changes that occur subsequent to a species invasion, an issue of particular focus among conservation biologists. Colonizing a novel environment presents a genetic challenge to invading species because such species surely have not experienced the selective pressures presented by the environment. Here we ask, by what mechanisms and processes do alien species genetically naïve to their new environment, become successful invaders? We attempt to resolve this paradox by considering the interplay between an invader’s ability to modify its new environment, and genetic modifications imposed by the new environment. We postulate that epigenetic adaptations, and adaptive mutations are likely play a role in enhancing invasion success.     

Beyond co-ethnicity: the politics of differentiating and integrating new immigrants in Singapore

This essay joins the ongoing debates about the role of co-ethnic ties in the making of diaspora identity by examining Singaporean Chinese perceptions of new immigrants from the mainland and the state's strategies in integrating the newcomers. The public discourses on new Chinese immigrants have produced three interlinked narratives: (1) newcomers are socially and culturally different from the mainstream and earlier immigrants; (2) newcomers have intensified the competition for scarce resources; and (3) newcomers are politically attached to China, whose rise as a global power only serves to reinforce such linkages. I argue that co-ethnicity and common cultural heritage play little role in shaping local Singaporeans' view of the new diaspora; instead, political pragmatism and new identity politics that prioritize the nation above ethnicity are the key factors influencing public attitudes and policy options regarding new immigrants. Furthermore, intra-diaspora differences/conflicts have reinforced interracial solidarity and contributed to the nation-building project.     

Population genetics of the black ant Formica lemani (Hymenoptera: Formicidae)

Colony kin structure and spatial population structure were studied in multiple populations of the ant Formica lemani , using allozymes and DNA microsatellites. Average genetic relatedness between nestmate workers varied little between populations ( r  = 0.51–0.76), indicating that the average colony kin structure was relatively simple. Worker genotypes could not be explained with a single breeding pair in all nests, however, and the distribution of relatedness estimates across nests was bimodal, suggesting that single- and multi-queen colonies co-occur. We studied spatial population structure in a successional boreal forest system, which is a mixture of different aged habitats. Newly clear-cut open habitat patches are quickly colonized by F. lemani , where it is able to persist for a limited number of generations. Newly-founded populations showed signs of a founder effect and spatial substructuring, whereas older populations were more homogenous. This suggests that new populations are founded by a limited number of colonizers arriving from more than one source. Genetic differentiation among local populations was minor, indicating strong migration between them. There were, however, indications of both isolation by distance and populations becoming more isolated as habitat patches grew older.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 247–258.