Species invasions are a principal component of global change, causing large losses in biodiversity as well as economic damage. Invasion theory attempts to understand and predict invasion success and patterns of spread. However, there is no consensus regarding which species or community attributes enhance invader success or explain spread dynamics. Experimental and theoretical studies suggest that regulation of spread dynamics is possible; however, the conditions for its existence have not yet been empirically demonstrated. If invasion spread is a regulated process, the structure that accounts for this regulation will be a main determinant of invasion dynamics. Here we explore the existence of regulation underlying changes in the rate of new site colonization. We employ concepts and analytical tools from the study of abundance dynamics and show that spread dynamics are, in fact, regulated processes and that the regulation structure is notably consistent among invasions occurring in widely different contexts. We base our conclusions on the analysis of the spread dynamics of 30 species invasions, including birds, amphibians, fish, invertebrates, plants, and a virus, all of which exhibited similar regulation structures. In contrast to current beliefs that species invasions are idiosyncratic phenomena, here we provide evidence that general patterns do indeed exist.conservation ͉ invasion ͉ population dynamics ͉ range expansion ͉ regulation

International audienceThe marine areas of South America (SA) include almost 30,000 km of coastline and encompass three different oceanic domains--the Caribbean, the Pacific, and the Atlantic--ranging in latitude from 12°N to 55°S. The 10 countries that border these coasts have different research capabilities and taxonomic traditions that affect taxonomic knowledge. This paper analyzes the status of knowledge of marine biodiversity in five subregions along the Atlantic and Pacific coasts of South America (SA): the Tropical East Pacific, the Humboldt Current, the Patagonian Shelf, the Brazilian Shelves, and the Tropical West Atlantic, and it provides a review of ecosystem threats and regional marine conservation strategies. South American marine biodiversity is least well known in the tropical subregions (with the exception of Costa Rica and Panama). Differences in total biodiversity were observed between the Atlantic and Pacific oceans at the same latitude. In the north of the continent, the Tropical East Pacific is richer in species than the Tropical West Atlantic, however, when standardized by coastal length, there is very little difference among them. In the south, the Humboldt Current system is much richer than the Patagonian Shelf. An analysis of endemism shows that 75% of the species are reported within only one of the SA regions, while about 22% of the species of SA are not reported elsewhere in the world. National and regional initiatives focusing on new exploration, especially to unknown areas and ecosystems, as well as collaboration among countries are fundamental to achieving the goal of completing inventories of species diversity and distribution. These inventories will allow accurate interpretation of the biogeography of its two oceanic coasts and latitudinal trends, and will also provide relevant information for science based policie

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Native and non-indigenous boring polychaetes in Chile: a threat to native and commercial mollusc species ABSTRACTBoring polychaetes infesting the shells of aquacultured molluscs affect host fitness and cause serious economic problems for the aquaculture industry. In Chile, knowledge of the native and non-indigenous polychaete fauna associated with mollusc hosts is limited, in spite of the fact that numerous native and nonindigenous mollusc species are actively harvested. We present the first complete list of boring polychaete species present in Chile, with a review of the information regarding each species' status as a native or nonindigenous species (NIS), together with information on native and introduced ranges, affected host species, likely vectors of introduction and donor areas. We recorded a total of nine boring polychaetes present along the Chilean coast including native and NIS. Within the NIS category we provide the first published report of the Sabellid Terebrasabella heterouncinata in South America. Boring polychaetes utilized both native and introduced host species. The finding of polychaete species which utilized multiple native and NIS hosts, indicates a potential risk for spread between aquaculture facilities and the natural environment. Our analysis suggests that aquaculture activities are probably the primary introduction vector for boring polychaete species to Chile and that this region does not differ in the magnitude of introduced boring polychaetes relative to other regions of the world. We discuss current laws and management regarding polychaete infestations and make recommendations for future management in Chile, which should contemplate a rational compromise between the socio-economic needs of the country and plans to protect and preserve the nation's biodiversity.

On the central coast of Chile, distribution of body size in Graus nigra varied with tidal pool height. With the objective of determining whether environmental temperature is one of the possible causes which explains the observed distribution pattern, two behavioural responses were analysed during an experimental period of increasing water temperature: number of opercular movements (an indirect measure of energy expenditure) and activity levels. The interactions of temperature time and body size time had a significant effect on the number of opercular movements. At low temperatures (13-15 C), large fish reached a maximum number of opercular movements, while small fish reached a maximum only at high temperatures (23-25 C). The interaction temperature time had a significant effect on activity levels of different body sizes. In general, large fish appeared to be less active than small fish, however, at very high temperatures (24-26 C) all individuals increased their activity levels. These data indicate that small fish are acclimatized to live in a wider range of temperatures (13-23 C), and, for fish of all body sizes, the highest temperatures (23-26 C) probably constitute a suboptimal microhabitat.

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Resumen.-Mastocarpus sp. es un alga roja nativa a la costa del Pacífico de Norteamérica, y también presente en Concepción, Chile (ca. 37°S), donde se ha propuesto como especie no indígena. Su establecimiento y expansión podrían verse favorecidos si láminas y papilas constituyeran propágulos. Las características de desprendimiento de estas dos estructuras apoyan esta interpretación. Láminas de Mastocarpus sp. requirieron menos fuerza para ser desprendidas desde las rocas que láminas de otras algas rojas comunes. Asimismo, un estimado mensual de 14,9% de las papilas con cistocarpos maduros se desprenden de láminas sometidas a turbulencia en laboratorio. Además, es común encontrar láminas y papilas a la deriva, y liberan esporas de pigmentación normal. La distribución de papilas a lo largo de las láminas, considerando su madurez, sugiere un patrón de desprendimiento predecible. Papilas nuevas fueron más abundantes en segmentos distales de láminas, y papilas viejas en segmentos centrales. La abundancia de cicatrices dejadas por papilas desprendidas fue mayor en segmentos basales, sugiriendo que las papilas que dejaron esas cicatrices portaban cistocarpos maduros. Concluimos que los puntos de adhesión de láminas y papilas se tornarían relativamente más débiles a medida que crecen, facilitando su desprendimiento. Esto no representa la abscisión de estructuras senescentes ya que en su interior crecen carpoesporofitos con esporas que pueden ser liberadas. Esto facilitaría el establecimiento de nuevos individuos a distancias y lugares diferentes de los que alcanzarían las esporas, pudiendo ser consideradas como estructuras alternativas de dispersión. Como tales, podrían afectar la dinámica poblacional y expansión de rango de Mastocarpus sp. en Chile.Palabras clave: Desprendimiento, especie no indígena, estrategia de dispersión, fragmentos a la deriva, Phyllophoraceae Abstract.-Mastocarpus sp. is a red macroalga native to the Pacific coast of North America, and present around Concepción, Chile (ca. 37°S), where it has been suggested as a non-indigenous species. Its establishment and expansion could be favored if blades and papillae function as propagules. The characteristics of the detachment of these two structures support this interpretation. Blades of Mastocarpus sp. become detached from rocks more readily than other common, bladed red seaweeds. In turn, a monthly estimate of up to 14.9% of papillae carrying mature cystocarps easily broke off from blades when experimentally subjected to turbulence in the laboratory. Additionally, blades and papillae are commonly found drifting, and release normally pigmented spores. The distribution of papillae along the blades, considering their maturity, suggests a predictable detachment pattern. New papillae were more abundant on distal segments, old papillae on middle segments, and scars of shed papillae on basal segments, suggesting that shed papillae carried mature cystocarps. We conclude that blades and papillae have attachment points that become relatively weaker as they grow a...