Madhur Anand, Andrew Gonzalez, Frédéric Guichard, Jurek Kolasa and Lael Parrott
Article: Ecological Systems as Complex Systems: Challenges for an Emerging Science
Diversity 2010, 2(3), 395-410; doi:10.3390/d2030395 - published online 15 March 2010
Show/Hide AbstractAbstract: Complex systems science has contributed to our understanding of ecology in important areas such as food webs, patch dynamics and population fluctuations. This has been achieved through the use of simple measures that can capture the difference between order and disorder and simple models with local interactions that can generate surprising behaviour at larger scales. However, close examination reveals that commonly applied definitions of complexity fail to accommodate some key features of ecological systems, a fact that will limit the contribution of complex systems science to ecology. We highlight these features of ecological complexity—such as diversity, cross-scale interactions, memory and environmental variability—that continue to challenge classical complex systems science. Further advances in these areas will be necessary before complex systems science can be widely applied to understand the dynamics of ecological systems.

Hans-Rolf Gregorius
Article: Linking Diversity and Differentiation
Diversity 2010, 2(3), 370-394; doi:10.3390/d2030370 - published online 3 March 2010
Show/Hide AbstractAbstract: Generally speaking, the term differentiation refers to differences between collections for the distribution of specified traits of their members, while diversity deals with (effective) numbers of trait states (types). Counting numbers of types implies discrete traits such as alleles and genotypes in population genetics or species and taxa in ecology. Comparisons between the concepts of differentiation and diversity therefore primarily refer to discrete traits. Diversity is related to differentiation through the idea that the total diversity of a subdivided collection should be composed of the diversity within the subcollections and a complement called “diversity between subcollections”. The idea goes back to the perception that the mixing of differentiated collections increases diversity. Several existing concepts of “diversity between subcollections” are based on this idea. Among them, β-diversity and fixation (inadvertently called differentiation) are the most prominent in ecology and in population genetics, respectively. The pertaining measures are shown to quantify the effect of differentiation in terms of diversity components, though from a dual perspective: the classical perspective of differentiation between collections for their type compositions, and the reverse perspective of differentiation between types for their collection affiliations. A series of measures of diversity-oriented differentiation is presented that consider this dual perspective at two levels of diversity partitioning: the overall type or subcollection diversity and the joint type-subcollection diversity. It turns out that, in contrast with common notions, the measures of fixation (such as F_ST or G_ST ) refer to the perspective of type rather than subcollection differentiation. This unexpected observation strongly suggests that the popular interpretations of fixation measures must be reconsidered.

Janis B. Nuckolls
Article: The Sound-Symbolic Expression of Animacy in Amazonian Ecuador
Diversity 2010, 2(3), 353-369; doi:10.3390/d2030353 - published online 2 March 2010
Show/Hide AbstractAbstract: Several anthropologists of Amazonian societies in Ecuador have claimed that for Achuar [1] and Quichua speaking Runa [2-4] there is no fundamental distinction between humans on the one hand, and plants and animals on the other. A related observation is that Runa and Achuar people share an animistic cosmology whereby animals, plants, and even seemingly inert entities such as rocks and stones are believed to have a life force or essence with a subjectivity that can be expressed. This paper will focus on Quichua speaking Runa to seek linguistic evidence for animacy by examining the sound-symbolic properties of a class of expressions called ideophones. I argue that structural features of ideophones such as canonical length and diversity of sound segments as well as type of sound segments, help express the animism of the Runa lifeworld. Moreover, although these features are not indicative of any essential distinctions between plants and animals, they may be indicative of a scalar view of animacy, along the lines suggested by Descola who first proposed a continuum or ‘ladder of animacy’ for the Achuar [1, pp. 321-326]. Ideophones, then, may be understood as one set of linguistic tools for coming to terms with the diversity of their ecological setting, a setting which spans highly animate humans and animals, through less animate plants, trees, and rocks.

Stéphen Rostain
Article: Pre-Columbian Earthworks in Coastal Amazonia
Diversity 2010, 2(3), 331-352; doi:10.3390/d2030331 - published online 2 March 2010
Show/Hide AbstractAbstract: As in other parts of Amazonia, pre-Columbian Indians have profoundly modified the coast of the Guianas. Between 650 and 1650 AD, Arauquinoid people occupied a territory that was approximately 600 km long and used the raised field technique intensively before the European conquest. They erected thousands of raised fields of various shapes, dug canals, ditches, and pathways, and built artificial mounds to establish their villages. All these earthworks changed forever the face of the coastal flooded savannas and their ecology. Such labor was probably organized under the leadership of a central authority: it seems that Arauquinoid societies were organized in a chiefdom system. Statistical calculations, based on the known surface area of raised fields and on their estimated productivity, suggest a population density of 50 to 100 inhabitants per km². Pre-Columbian inhabitants of the Guianas coast carefully organized, managed and “anthropisized” their territory following a specific pattern.

Jacques Robert
Review: Emerging Ranaviral Infectious Diseases and Amphibian Decline
Diversity 2010, 2(3), 314-330; doi:10.3390/d2030314 - published online 26 February 2010
Show/Hide AbstractAbstract: Infectious diseases caused by ranaviruses (RV, family Iridoviridae) not only affect wild amphibian populations but also agriculture and international animal trade. Although, the prevalence of RV infections and die offs has markedly increased over the last decade, it is still unclear whether these viruses are direct causal agents of extinction or rather are the resulting (secondary) consequences of weakened health of amphibian populations leading to increased susceptibility to viral pathogens. In either case, it is important to understand the critical role of host immune defense in controlling RV infections, pathogenicity, and transmission; this is the focus of this review.

Andrew R. Blaustein, Susan C. Walls, Betsy A. Bancroft, Joshua J. Lawler, Catherine L. Searle and Stephanie S. Gervasi
Article: Direct and Indirect Effects of Climate Change on Amphibian Populations
Diversity 2010, 2(2), 281-313; doi:10.3390/d2020281 - published online 25 February 2010
Show/Hide AbstractAbstract: As part of an overall decline in biodiversity, populations of many organisms are declining and species are being lost at unprecedented rates around the world. This includes many populations and species of amphibians. Although numerous factors are affecting amphibian populations, we show potential direct and indirect effects of climate change on amphibians at the individual, population and community level. Shifts in amphibian ranges are predicted. Changes in climate may affect survival, growth, reproduction and dispersal capabilities. Moreover, climate change can alter amphibian habitats including vegetation, soil, and hydrology. Climate change can influence food availability, predator-prey relationships and competitive interactions which can alter community structure. Climate change can also alter pathogen-host dynamics and greatly influence how diseases are manifested. Changes in climate can interact with other stressors such as UV-B radiation and contaminants. The interactions among all these factors are complex and are probably driving some amphibian population declines and extinctions.